WorldWideScience

Sample records for monocular vision based

  1. A Monocular Vision Based Approach to Flocking

    Science.gov (United States)

    2006-03-01

    The bird represented with the green triangle desires to move away from its neighbors to avoid overcrowding . The bird reacts the most strongly to the... brightness gradients [35], neural networks [18, 19], and other vision-based methods [6, 26, 33]. For the purposes of this thesis effort, it is assumed that...Once started, however, maneuver waves spread through the flock at a mean speed of less than 15 milliseconds [43]. 2.5.3 Too Perfect. In nature, a bird

  2. Building a 3D scanner system based on monocular vision.

    Science.gov (United States)

    Zhang, Zhiyi; Yuan, Lin

    2012-04-10

    This paper proposes a three-dimensional scanner system, which is built by using an ingenious geometric construction method based on monocular vision. The system is simple, low cost, and easy to use, and the measurement results are very precise. To build it, one web camera, one handheld linear laser, and one background calibration board are required. The experimental results show that the system is robust and effective, and the scanning precision can be satisfied for normal users.

  3. Automatic gear sorting system based on monocular vision

    Directory of Open Access Journals (Sweden)

    Wenqi Wu

    2015-11-01

    Full Text Available An automatic gear sorting system based on monocular vision is proposed in this paper. A CCD camera fixed on the top of the sorting system is used to obtain the images of the gears on the conveyor belt. The gears׳ features including number of holes, number of teeth and color are extracted, which is used to categorize the gears. Photoelectric sensors are used to locate the gears׳ position and produce the trigger signals for pneumatic cylinders. The automatic gear sorting is achieved by using pneumatic actuators to push different gears into their corresponding storage boxes. The experimental results verify the validity and reliability of the proposed method and system.

  4. Stochastically optimized monocular vision-based navigation and guidance

    Science.gov (United States)

    Watanabe, Yoko

    The objective of this thesis is to design a relative navigation and guidance law for unmanned aerial vehicles, or UAVs, for vision-based control applications. The autonomous operation of UAVs has progressively developed in recent years. In particular, vision-based navigation, guidance and control has been one of the most focused on research topics for the automation of UAVs. This is because in nature, birds and insects use vision as the exclusive sensor for object detection and navigation. Furthermore, it is efficient to use a vision sensor since it is compact, light-weight and low cost. Therefore, this thesis studies the monocular vision-based navigation and guidance of UAVs. Since 2-D vision-based measurements are nonlinear with respect to the 3-D relative states, an extended Kalman filter (EKF) is applied in the navigation system design. The EKF-based navigation system is integrated with a real-time image processing algorithm and is tested in simulations and flight tests. The first closed-loop vision-based formation flight between two UAVs has been achieved, and the results are shown in this thesis to verify the estimation performance of the EKF. In addition, vision-based 3-D terrain recovery was performed in simulations to present a navigation design which has the capability of estimating states of multiple objects. In this problem, the statistical z-test is applied to solve the correspondence problem of relating measurements and estimation states. As a practical example of vision-based control applications for UAVs, a vision-based obstacle avoidance problem is specially addressed in this thesis. A navigation and guidance system is designed for a UAV to achieve a mission of waypoint tracking while avoiding unforeseen stationary obstacles by using vision information. An EKF is applied to estimate each obstacles' position from the vision-based information. A collision criteria is established by using a collision-cone approach and a time-to-go criterion. A minimum

  5. A monocular vision system based on cooperative targets detection for aircraft pose measurement

    Science.gov (United States)

    Wang, Zhenyu; Wang, Yanyun; Cheng, Wei; Chen, Tao; Zhou, Hui

    2017-08-01

    In this paper, a monocular vision measurement system based on cooperative targets detection is proposed, which can capture the three-dimensional information of objects by recognizing the checkerboard target and calculating of the feature points. The aircraft pose measurement is an important problem for aircraft’s monitoring and control. Monocular vision system has a good performance in the range of meter. This paper proposes an algorithm based on coplanar rectangular feature to determine the unique solution of distance and angle. A continuous frame detection method is presented to solve the problem of corners’ transition caused by symmetry of the targets. Besides, a displacement table test system based on three-dimensional precision and measurement system human-computer interaction software has been built. Experiment result shows that it has a precision of 2mm in the range of 300mm to 1000mm, which can meet the requirement of the position measurement in the aircraft cabin.

  6. A Novel Ship-Bridge Collision Avoidance System Based on Monocular Computer Vision

    Directory of Open Access Journals (Sweden)

    Yuanzhou Zheng

    2013-06-01

    Full Text Available The study aims to investigate the ship-bridge collision avoidance. A novel system for ship-bridge collision avoidance based on monocular computer vision is proposed in this study. In the new system, the moving ships are firstly captured by the video sequences. Then the detection and tracking of the moving objects have been done to identify the regions in the scene that correspond to the video sequences. Secondly, the quantity description of the dynamic states of the moving objects in the geographical coordinate system, including the location, velocity, orientation, etc, has been calculated based on the monocular vision geometry. Finally, the collision risk is evaluated and consequently the ship manipulation commands are suggested, aiming to avoid the potential collision. Both computer simulation and field experiments have been implemented to validate the proposed system. The analysis results have shown the effectiveness of the proposed system.

  7. Monocular Vision-Based Robot Localization and Target Tracking

    Directory of Open Access Journals (Sweden)

    Bing-Fei Wu

    2011-01-01

    Full Text Available This paper presents a vision-based technology for localizing targets in 3D environment. It is achieved by the combination of different types of sensors including optical wheel encoders, an electrical compass, and visual observations with a single camera. Based on the robot motion model and image sequences, extended Kalman filter is applied to estimate target locations and the robot pose simultaneously. The proposed localization system is applicable in practice because it is not necessary to have the initializing setting regarding starting the system from artificial landmarks of known size. The technique is especially suitable for navigation and target tracing for an indoor robot and has a high potential extension to surveillance and monitoring for Unmanned Aerial Vehicles with aerial odometry sensors. The experimental results present “cm” level accuracy of the localization of the targets in indoor environment under a high-speed robot movement.

  8. Monocular vision based navigation method of mobile robot

    Institute of Scientific and Technical Information of China (English)

    DONG Ji-wen; YANG Sen; LU Shou-yin

    2009-01-01

    A trajectory tracking method is presented for the visual navigation of the monocular mobile robot. The robot move along line trajectory drawn beforehand, recognized and stop on the stop-sign to finish special task. The robot uses a forward looking colorful digital camera to capture information in front of the robot, and by the use of HSI model partition the trajectory and the stop-sign out. Then the "sampling estimate" method was used to calculate the navigation parameters. The stop-sign is easily recognized and can identify 256 different signs. Tests indicate that the method can fit large-scale intensity of brightness and has more robustness and better real-time character.

  9. Measuring method for the object pose based on monocular vision technology

    Science.gov (United States)

    Sun, Changku; Zhang, Zimiao; Wang, Peng

    2010-11-01

    Position and orientation estimation of the object, which can be widely applied in the fields as robot navigation, surgery, electro-optic aiming system, etc, has an important value. The monocular vision positioning algorithm which is based on the point characteristics is studied and new measurement method is proposed in this paper. First, calculate the approximate coordinates of the five reference points which can be used as the initial value of iteration in the camera coordinate system according to weakp3p; Second, get the exact coordinates of the reference points in the camera coordinate system through iterative calculation with the constraints relationship of the reference points; Finally, get the position and orientation of the object. So the measurement model of monocular vision is constructed. In order to verify the accuracy of measurement model, a plane target using infrared LED as reference points is designed to finish the verification of the measurement method and the corresponding image processing algorithm is studied. And then The monocular vision experimental system is established. Experimental results show that the translational positioning accuracy reaches +/-0.05mm and rotary positioning accuracy reaches +/-0.2o .

  10. Mobile Target Tracking Based on Hybrid Open-Loop Monocular Vision Motion Control Strategy

    Directory of Open Access Journals (Sweden)

    Cao Yuan

    2015-01-01

    Full Text Available This paper proposes a new real-time target tracking method based on the open-loop monocular vision motion control. It uses the particle filter technique to predict the moving target’s position in an image. Due to the properties of the particle filter, the method can effectively master the motion behaviors of the linear and nonlinear. In addition, the method uses the simple mathematical operation to transfer the image information in the mobile target to its real coordinate information. Therefore, it requires few operating resources. Moreover, the method adopts the monocular vision approach, which is a single camera, to achieve its objective by using few hardware resources. Firstly, the method evaluates the next time’s position and size of the target in an image. Later, the real position of the objective corresponding to the obtained information is predicted. At last, the mobile robot should be controlled in the center of the camera’s vision. The paper conducts the tracking test to the L-type and the S-type and compares with the Kalman filtering method. The experimental results show that the method achieves a better tracking effect in the L-shape experiment, and its effect is superior to the Kalman filter technique in the L-type or S-type tracking experiment.

  11. Robust Range Estimation with a Monocular Camera for Vision-Based Forward Collision Warning System

    Directory of Open Access Journals (Sweden)

    Ki-Yeong Park

    2014-01-01

    Full Text Available We propose a range estimation method for vision-based forward collision warning systems with a monocular camera. To solve the problem of variation of camera pitch angle due to vehicle motion and road inclination, the proposed method estimates virtual horizon from size and position of vehicles in captured image at run-time. The proposed method provides robust results even when road inclination varies continuously on hilly roads or lane markings are not seen on crowded roads. For experiments, a vision-based forward collision warning system has been implemented and the proposed method is evaluated with video clips recorded in highway and urban traffic environments. Virtual horizons estimated by the proposed method are compared with horizons manually identified, and estimated ranges are compared with measured ranges. Experimental results confirm that the proposed method provides robust results both in highway and in urban traffic environments.

  12. Indoor Mobile Robot Navigation by Central Following Based on Monocular Vision

    Science.gov (United States)

    Saitoh, Takeshi; Tada, Naoya; Konishi, Ryosuke

    This paper develops the indoor mobile robot navigation by center following based on monocular vision. In our method, based on the frontal image, two boundary lines between the wall and baseboard are detected. Then, the appearance based obstacle detection is applied. When the obstacle exists, the avoidance or stop movement is worked according to the size and position of the obstacle, and when the obstacle does not exist, the robot moves at the center of the corridor. We developed the wheelchair based mobile robot. We estimated the accuracy of the boundary line detection, and obtained fast processing speed and high detection accuracy. We demonstrate the effectiveness of our mobile robot by the stopping experiments with various obstacles and moving experiments.

  13. Detection and Tracking Strategies for Autonomous Aerial Refuelling Tasks Based on Monocular Vision

    Directory of Open Access Journals (Sweden)

    Yingjie Yin

    2014-07-01

    Full Text Available Detection and tracking strategies based on monocular vision are proposed for autonomous aerial refuelling tasks. The drogue attached to the fuel tanker aircraft has two important features. The grey values of the drogue's inner part are different from the external umbrella ribs, as shown in the image. The shape of the drogue's inner dark part is nearly circular. According to crucial prior knowledge, the rough and fine positioning algorithms are designed to detect the drogue. Particle filter based on the drogue's shape is proposed to track the drogue. A strategy to switch between detection and tracking is proposed to improve the robustness of the algorithms. The inner dark part of the drogue is segmented precisely in the detecting and tracking process and the segmented circular part can be used to measure its spatial position. The experimental results show that the proposed method has good performance in real-time and satisfied robustness and positioning accuracy.

  14. Monocular Vision SLAM for Indoor Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Koray Çelik

    2013-01-01

    Full Text Available This paper presents a novel indoor navigation and ranging strategy via monocular camera. By exploiting the architectural orthogonality of the indoor environments, we introduce a new method to estimate range and vehicle states from a monocular camera for vision-based SLAM. The navigation strategy assumes an indoor or indoor-like manmade environment whose layout is previously unknown, GPS-denied, representable via energy based feature points, and straight architectural lines. We experimentally validate the proposed algorithms on a fully self-contained microaerial vehicle (MAV with sophisticated on-board image processing and SLAM capabilities. Building and enabling such a small aerial vehicle to fly in tight corridors is a significant technological challenge, especially in the absence of GPS signals and with limited sensing options. Experimental results show that the system is only limited by the capabilities of the camera and environmental entropy.

  15. A Monocular Vision Sensor-Based Obstacle Detection Algorithm for Autonomous Robots

    Science.gov (United States)

    Lee, Tae-Jae; Yi, Dong-Hoon; Cho, Dong-Il “Dan”

    2016-01-01

    This paper presents a monocular vision sensor-based obstacle detection algorithm for autonomous robots. Each individual image pixel at the bottom region of interest is labeled as belonging either to an obstacle or the floor. While conventional methods depend on point tracking for geometric cues for obstacle detection, the proposed algorithm uses the inverse perspective mapping (IPM) method. This method is much more advantageous when the camera is not high off the floor, which makes point tracking near the floor difficult. Markov random field-based obstacle segmentation is then performed using the IPM results and a floor appearance model. Next, the shortest distance between the robot and the obstacle is calculated. The algorithm is tested by applying it to 70 datasets, 20 of which include nonobstacle images where considerable changes in floor appearance occur. The obstacle segmentation accuracies and the distance estimation error are quantitatively analyzed. For obstacle datasets, the segmentation precision and the average distance estimation error of the proposed method are 81.4% and 1.6 cm, respectively, whereas those for a conventional method are 57.5% and 9.9 cm, respectively. For nonobstacle datasets, the proposed method gives 0.0% false positive rates, while the conventional method gives 17.6%. PMID:26938540

  16. 3D Reconstruction from a Single Still Image Based on Monocular Vision of an Uncalibrated Camera

    Directory of Open Access Journals (Sweden)

    Yu Tao

    2017-01-01

    Full Text Available we propose a framework of combining Machine Learning with Dynamic Optimization for reconstructing scene in 3D automatically from a single still image of unstructured outdoor environment based on monocular vision of an uncalibrated camera. After segmenting image first time, a kind of searching tree strategy based on Bayes rule is used to identify the hierarchy of all areas on occlusion. After superpixel segmenting image second time, the AdaBoost algorithm is applied in the integration detection to the depth of lighting, texture and material. Finally, all the factors above are optimized with constrained conditions, acquiring the whole depthmap of an image. Integrate the source image with its depthmap in point-cloud or bilinear interpolation styles, realizing 3D reconstruction. Experiment in comparisons with typical methods in associated database demonstrates our method improves the reasonability of estimation to the overall 3D architecture of image’s scene to a certain extent. And it does not need any manual assist and any camera model information.

  17. A Monocular Vision Sensor-Based Obstacle Detection Algorithm for Autonomous Robots

    Directory of Open Access Journals (Sweden)

    Tae-Jae Lee

    2016-03-01

    Full Text Available This paper presents a monocular vision sensor-based obstacle detection algorithm for autonomous robots. Each individual image pixel at the bottom region of interest is labeled as belonging either to an obstacle or the floor. While conventional methods depend on point tracking for geometric cues for obstacle detection, the proposed algorithm uses the inverse perspective mapping (IPM method. This method is much more advantageous when the camera is not high off the floor, which makes point tracking near the floor difficult. Markov random field-based obstacle segmentation is then performed using the IPM results and a floor appearance model. Next, the shortest distance between the robot and the obstacle is calculated. The algorithm is tested by applying it to 70 datasets, 20 of which include nonobstacle images where considerable changes in floor appearance occur. The obstacle segmentation accuracies and the distance estimation error are quantitatively analyzed. For obstacle datasets, the segmentation precision and the average distance estimation error of the proposed method are 81.4% and 1.6 cm, respectively, whereas those for a conventional method are 57.5% and 9.9 cm, respectively. For nonobstacle datasets, the proposed method gives 0.0% false positive rates, while the conventional method gives 17.6%.

  18. Real-time drogue recognition and 3D locating for UAV autonomous aerial refueling based on monocular machine vision

    Institute of Scientific and Technical Information of China (English)

    Wang Xufeng; Kong Xingwei; Zhi Jianhui; Chen Yong; Dong Xinmin

    2015-01-01

    Drogue recognition and 3D locating is a key problem during the docking phase of the autonomous aerial refueling (AAR). To solve this problem, a novel and effective method based on monocular vision is presented in this paper. Firstly, by employing computer vision with red-ring-shape feature, a drogue detection and recognition algorithm is proposed to guarantee safety and ensure the robustness to the drogue diversity and the changes in environmental condi-tions, without using a set of infrared light emitting diodes (LEDs) on the parachute part of the dro-gue. Secondly, considering camera lens distortion, a monocular vision measurement algorithm for drogue 3D locating is designed to ensure the accuracy and real-time performance of the system, with the drogue attitude provided. Finally, experiments are conducted to demonstrate the effective-ness of the proposed method. Experimental results show the performances of the entire system in contrast with other methods, which validates that the proposed method can recognize and locate the drogue three dimensionally, rapidly and precisely.

  19. Outdoor autonomous navigation using monocular vision

    OpenAIRE

    Royer, Eric; Bom, Jonathan; Dhome, Michel; Thuilot, Benoît; Lhuillier, Maxime; Marmoiton, Francois

    2005-01-01

    International audience; In this paper, a complete system for outdoor robot navigation is presented. It uses only monocular vision. The robot is first guided on a path by a human. During this learning step, the robot records a video sequence. From this sequence, a three dimensional map of the trajectory and the environment is built. When this map has been computed, the robot is able to follow the same trajectory by itself. Experimental results carried out with an urban electric vehicle are sho...

  20. A smart telerobotic system driven by monocular vision

    Science.gov (United States)

    Defigueiredo, R. J. P.; Maccato, A.; Wlczek, P.; Denney, B.; Scheerer, J.

    1994-01-01

    A robotic system that accepts autonomously generated motion and control commands is described. The system provides images from the monocular vision of a camera mounted on a robot's end effector, eliminating the need for traditional guidance targets that must be predetermined and specifically identified. The telerobotic vision system presents different views of the targeted object relative to the camera, based on a single camera image and knowledge of the target's solid geometry.

  1. RBF-Based Monocular Vision Navigation for Small Vehicles in Narrow Space below Maize Canopy

    Directory of Open Access Journals (Sweden)

    Lu Liu

    2016-06-01

    Full Text Available Maize is one of the major food crops in China. Traditionally, field operations are done by manual labor, where the farmers are threatened by the harsh environment and pesticides. On the other hand, it is difficult for large machinery to maneuver in the field due to limited space, particularly in the middle and late growth stage of maize. Unmanned, compact agricultural machines, therefore, are ideal for such field work. This paper describes a method of monocular visual recognition to navigate small vehicles between narrow crop rows. Edge detection and noise elimination were used for image segmentation to extract the stalks in the image. The stalk coordinates define passable boundaries, and a simplified radial basis function (RBF-based algorithm was adapted for path planning to improve the fault tolerance of stalk coordinate extraction. The average image processing time, including network latency, is 220 ms. The average time consumption for path planning is 30 ms. The fast processing ensures a top speed of 2 m/s for our prototype vehicle. When operating at the normal speed (0.7 m/s, the rate of collision with stalks is under 6.4%. Additional simulations and field tests further proved the feasibility and fault tolerance of our method.

  2. Autonomous Landing and Ingress of Micro-Air-Vehicles in Urban Environments Based on Monocular Vision

    Science.gov (United States)

    Brockers, Roland; Bouffard, Patrick; Ma, Jeremy; Matthies, Larry; Tomlin, Claire

    2011-01-01

    Unmanned micro air vehicles (MAVs) will play an important role in future reconnaissance and search and rescue applications. In order to conduct persistent surveillance and to conserve energy, MAVs need the ability to land, and they need the ability to enter (ingress) buildings and other structures to conduct reconnaissance. To be safe and practical under a wide range of environmental conditions, landing and ingress maneuvers must be autonomous, using real-time, onboard sensor feedback. To address these key behaviors, we present a novel method for vision-based autonomous MAV landing and ingress using a single camera for two urban scenarios: landing on an elevated surface, representative of a rooftop, and ingress through a rectangular opening, representative of a door or window. Real-world scenarios will not include special navigation markers, so we rely on tracking arbitrary scene features; however, we do currently exploit planarity of the scene. Our vision system uses a planar homography decomposition to detect navigation targets and to produce approach waypoints as inputs to the vehicle control algorithm. Scene perception, planning, and control run onboard in real-time; at present we obtain aircraft position knowledge from an external motion capture system, but we expect to replace this in the near future with a fully self-contained, onboard, vision-aided state estimation algorithm. We demonstrate autonomous vision-based landing and ingress target detection with two different quadrotor MAV platforms. To our knowledge, this is the first demonstration of onboard, vision-based autonomous landing and ingress algorithms that do not use special purpose scene markers to identify the destination.

  3. Dynamic object recognition and tracking of mobile robot by monocular vision

    Science.gov (United States)

    Liu, Lei; Wang, Yongji

    2007-11-01

    Monocular Vision is widely used in mobile robot's motion control for its simple structure and easy using. An integrated description to distinguish and tracking the specified color targets dynamically and precisely by the Monocular Vision based on the imaging principle is the major topic of the paper. The mainline is accordance with the mechanisms of visual processing strictly, including the pretreatment and recognition processes. Specially, the color models are utilized to decrease the influence of the illumination in the paper. Some applied algorithms based on the practical application are used for image segmentation and clustering. After recognizing the target, however the monocular camera can't get depth information directly, 3D Reconstruction Principle is used to calculate the distance and direction from robot to target. To emend monocular camera reading, the laser is used after vision measuring. At last, a vision servo system is designed to realize the robot's dynamic tracking to the moving target.

  4. Monocular vision for intelligent wheelchair indoor navigation based on natural landmark matching

    Science.gov (United States)

    Xu, Xiaodong; Luo, Yuan; Kong, Weixi

    2010-08-01

    This paper presents a real-time navigation system in a behavior-based manner. We show that autonomous navigation is possible in different rooms with the use of a single camera and natural landmarks. Firstly the intelligent wheelchair is manually guided on a path passing through different rooms and a video sequence is recorded with a front-facing camera. A 3D structure map is then gotten from this learning sequence by calculating the natural landmarks. Finally, the intelligent wheelchair uses this map to compute its localization and it follows the learning path or a slightly different path to achieve the real-time navigation. Experimental results indicate that this method is effective even when the viewpoint and scale is changed.

  5. Zero Calibration of Delta Robot Based on Monocular Vision%基于单目视觉的 Delta 机器人零点标定方法

    Institute of Scientific and Technical Information of China (English)

    孙月海; 王兰; 梅江平; 张文昌; 刘艺

    2013-01-01

    For the precision of high-speed pick-and-place parallel robot with lower-mobility in practical engineering, a fast calibration approach was proposed based on vision metrology in this paper. To specify this method,by means of system analysis and reasonable mechanism simplification of Delta robot,a zero error model was established. A zero error identification model using monocular vision was constructed in plane measurement. The zero error could be identified only measuring the positional error of end-effector in x axis and y axis by monocular vision,when the mo-bile platform was in horizontal motion. The error compensation was realized by modifying the ideal zero point position of the system. Calibration experiment results show that the method is simple,effective and strongly practical.%  针对实际工程应用中少自由度高速抓放并联机器人的精度问题,提出了一种基于视觉测量的快速标定方法。以 Delta 机器人为例,通过系统分析和机构合理简化,建立了零点误差模型。构造出基于单目视觉平面测量的零点误差辨识模型,借助单目视觉仅检测机器人动平台沿水平面运动时末端 x 、 y 向的位置误差,识别出零点误差,进而修改零点位置实现末端位置误差补偿。标定实验结果表明该方法简单、有效、实用性强。

  6. Disseminated neurocysticercosis presenting as isolated acute monocular painless vision loss

    Directory of Open Access Journals (Sweden)

    Gaurav M Kasundra

    2014-01-01

    Full Text Available Neurocysticercosis, the most common parasitic infection of the nervous system, is known to affect the brain, eyes, muscular tissues and subcutaneous tissues. However, it is very rare for patients with ocular cysts to have concomitant cerebral cysts. Also, the dominant clinical manifestation of patients with cerebral cysts is either seizures or headache. We report a patient who presented with acute monocular painless vision loss due to intraocular submacular cysticercosis, who on investigation had multiple cerebral parenchymal cysticercal cysts, but never had any seizures. Although such a vision loss after initiation of antiparasitic treatment has been mentioned previously, acute monocular vision loss as the presenting feature of ocular cysticercosis is rare. We present a brief review of literature along with this case report.

  7. Aerial vehicles collision avoidance using monocular vision

    Science.gov (United States)

    Balashov, Oleg; Muraviev, Vadim; Strotov, Valery

    2016-10-01

    In this paper image-based collision avoidance algorithm that provides detection of nearby aircraft and distance estimation is presented. The approach requires a vision system with a single moving camera and additional information about carrier's speed and orientation from onboard sensors. The main idea is to create a multi-step approach based on a preliminary detection, regions of interest (ROI) selection, contour segmentation, object matching and localization. The proposed algorithm is able to detect small targets but unlike many other approaches is designed to work with large-scale objects as well. To localize aerial vehicle position the system of equations relating object coordinates in space and observed image is solved. The system solution gives the current position and speed of the detected object in space. Using this information distance and time to collision can be estimated. Experimental research on real video sequences and modeled data is performed. Video database contained different types of aerial vehicles: aircrafts, helicopters, and UAVs. The presented algorithm is able to detect aerial vehicles from several kilometers under regular daylight conditions.

  8. Monocular Vision: Occupational Limitations and Current Standards

    Science.gov (United States)

    2011-03-01

    Kumagai, J. K., Williams, S., and Kline, D. (2005), Vision standards for aircrew: Visual acuity for pilots, (DRDC-TORONTO-CR-2005-142), Greenley ...Canadian Forces aircrew, (DRDC-TORONTO-CR-2006-255), Greenley and Associate Inc., Ottawa. Lövsund, P., Hedin, A., and Törnros, J. (1991), Effects...Williams, S., Casson, E., Brooks, J., Greenley , M., and Nadeau, J. (2003), Visual acuity standard for divers, Greenley & Associates Incorporated

  9. Design of the Surgical Navigation Based on Monocular Vision%单目视觉手术导航的系统设计

    Institute of Scientific and Technical Information of China (English)

    刘大鹏; 张巍; 徐子昂

    2016-01-01

    Objective: Existing orthopedic surgical navigation system makes surgery accurate and intraoperative X-ray exposure reduce to the traditional surgery, but the apparatus body is large and operation complicate, difficult to effectively shorten the operation time. This paper introduces a monocular vision navigation system to solve this problem. Methods: Monocular vision navigation using visible light image processing system, and set the overall hardware platform based on validated algorithms and designs used for knee replacement surgery procedures. Result & Conclusion: Relative to the previous method of non-contact dimensional localization, our system can keep the accuracy while reducing the hardware volume and simplifying the navigation process, also has features such as iterative development, low cost, particularly suitable for medium and small orthopaedics surgery.%目的:现有的骨科手术导航系统在提高手术精度和减少术中X线暴露方面具有传统手术无法比拟的优势,但设备体较大,操作繁琐,难以有效缩短手术时间。因此,介绍一种利用可见光的单目视觉导航系统解决此问题。方法:采用可见光的单目视觉作为手术导航的图像处理系统,并在此基础上设定整体硬件平台,验证相关算法,并设计了针对膝关节置换手术的使用操作流程。结果及结论:相对以往的非接触式立体定位方法,本系统在保证精度的同时减小设备体积,简化导航流程,兼具可重复开发、成本低廉等特性,适用于中小型骨科手术。

  10. 基于单目视觉的纵向车间距检测研究%Research on Detection of Longitudinal Vehicle Spacing Based on Monocular Vision

    Institute of Scientific and Technical Information of China (English)

    杨炜; 魏朗; 巩建强; 张倩

    2012-01-01

    提出了一种在结构化公路上基于单目视觉的纵向车间距的检测方法;利用Hough变换识别两侧车道标识线,确定前方车辆识别区域,检测并跟踪本车道内的前方车辆,在传统的静态单帧图像测距模型的基础上,建立了一种改进的静态单帧图像测距模型,并实现了纵向车间距的测量;实验结果表明,该方法能够实时识别跟踪前方车辆,准确检测纵向车间距,其测量值与真实测量值相比较,误差比较小,测量精度较为准确,完全能够满足实际测距要求,是一种非常有效的纵向车间距检测方法,具有较强的通用性.%A new detection method of longitudinal vehicle spacing based on monocular vision is proposed. Using Hough transform recognition on both sides of driveway logo lane, determine leading vehicle identification area, detection and tracking the front vehicle in the lane, on the basis of traditional static single frame image ranging model, establishing a modified static single frame image ranging model ?finished the detection of longitudinal vehicle spacing. The experimental results show that this method could real-time identification leading vehicle, accurately detection of longitudinal vehicle spacing, the measured value compared with the real value measurement, the error are small, measurement accuracy is more accurate, could meet the practical needs, is a kind of effective longitudinal vehicle spacing detection method, has strong generality.

  11. Development of a monocular vision system for robotic drilling

    Institute of Scientific and Technical Information of China (English)

    Wei-dong ZHU; Biao MEI; Guo-rui YAN; Ying-lin KE

    2014-01-01

    Robotic drilling for aerospace structures demands a high positioning accuracy of the robot, which is usually achieved through error measurement and compensation. In this paper, we report the development of a practical monocular vision system for measurement of the relative error between the drill tool center point (TCP) and the reference hole. First, the principle of relative error measurement with the vision system is explained, followed by a detailed discussion on the hardware components, software components, and system integration. The elliptical contour extraction algorithm is presented for accurate and robust reference hole detection. System calibration is of key importance to the measurement accuracy of a vision system. A new method is proposed for the simultaneous calibration of camera internal parameters and hand-eye relationship with a dedicated calibration board. Extensive measurement experiments have been performed on a robotic drilling system. Experimental results show that the measurement accuracy of the developed vision system is higher than 0.15 mm, which meets the requirement of robotic drilling for aircraft structures.

  12. Novel approach for mobile robot localization using monocular vision

    Science.gov (United States)

    Zhong, Zhiguang; Yi, Jianqiang; Zhao, Dongbin; Hong, Yiping

    2003-09-01

    This paper presents a novel approach for mobile robot localization using monocular vision. The proposed approach locates a robot relative to the target to which the robot moves. Two points are selected from the target as two feature points. Once the coordinates in an image of the two feature points are detected, the position and motion direction of the robot can be determined according to the detected coordinates. Unlike those reported geometry pose estimation or landmarks matching methods, this approach requires neither artificial landmarks nor an accurate map of indoor environment. It needs less computation and can simplify greatly the localization problem. The validity and flexibility of the proposed approach is demonstrated by experiments performed on real images. The results show that this new approach is not only simple and flexible but also has high localization precision.

  13. 基于单目视觉的微型空中机器人自主悬停控制%Autonomous hovering control based on monocular vision for micro aerial robot

    Institute of Scientific and Technical Information of China (English)

    张洪涛; 李隆球; 张广玉; 王武义

    2014-01-01

    针对微型空中机器人在室内环境下无法借助外部定位系统实现自主悬停的问题,提出一种基于单目视觉的自主悬停控制方法。采用一种四成分特征点描述符和一个多级筛选器进行特征点跟踪。根据单目视觉运动学估计机器人水平位置;根据低雷诺数下的空气阻力估计机器人飞行速度;结合位置和速度信息对机器人进行悬停控制。实验结果验证了该方法的有效性。%A hovering control method based on onboard monocular vision is proposed to hover a micro aerial robot autonomously, in which there is no external positioning system in indoor environments. A descriptor with four components and a multi-stage filter are used for feature tracking. Horizontal position is estimated according to monocular vision kinematics. Flight speed is estimated according to aerodynamic drag at low Reynolds number. Position and velocity informations are fused to hover the robot. Experimental results show the effectiveness of the proposed approach.

  14. Mobile Robot Hierarchical Simultaneous Localization and Mapping Using Monocular Vision

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A hierarchical mobile robot simultaneous localization and mapping (SLAM) method that allows us to obtain accurate maps was presented. The local map level is composed of a set of local metric feature maps that are guaranteed to be statistically independent. The global level is a topological graph whose arcs are labeled with the relative location between local maps. An estimation of these relative locations is maintained with local map alignment algorithm, and more accurate estimation is calculated through a global minimization procedure using the loop closure constraint. The local map is built with Rao-Blackwellised particle filter (RBPF), where the particle filter is used to extending the path posterior by sampling new poses. The landmark position estimation and update is implemented through extended Kalman filter (EKF). Monocular vision mounted on the robot tracks the 3D natural point landmarks, which are structured with matching scale invariant feature transform (SIFT) feature pairs. The matching for multi-dimension SIFT features is implemented with a KD-tree in the time cost of O(lbN). Experiment results on Pioneer mobile robot in a real indoor environment show the superior performance of our proposed method.

  15. MONOCULAR AND BINOCULAR VISION IN THE PERFORMANCE OF A COMPLEX SKILL

    Directory of Open Access Journals (Sweden)

    Thomas Heinen

    2011-09-01

    Full Text Available The goal of this study was to investigate the role of binocular and monocular vision in 16 gymnasts as they perform a handspring on vault. In particular we reasoned, if binocular visual information is eliminated while experts and apprentices perform a handspring on vault, and their performance level changes or is maintained, then such information must or must not be necessary for their best performance. If the elimination of binocular vision leads to differences in gaze behavior in either experts or apprentices, this would answer the question of an adaptive gaze behavior, and thus if this is a function of expertise level or not. Gaze behavior was measured using a portable and wireless eye-tracking system in combination with a movement-analysis system. Results revealed that gaze behavior differed between experts and apprentices in the binocular and monocular conditions. In particular, apprentices showed less fixations of longer duration in the monocular condition as compared to experts and the binocular condition. Apprentices showed longer blink duration than experts in both, the monocular and binocular conditions. Eliminating binocular vision led to a shorter repulsion phase and a longer second flight phase in apprentices. Experts exhibited no differences in phase durations between binocular and monocular conditions. Findings suggest, that experts may not rely on binocular vision when performing handsprings, and movement performance maybe influenced in apprentices when eliminating binocular vision. We conclude that knowledge about gaze-movement relationships may be beneficial for coaches when teaching the handspring on vault in gymnastics

  16. An appearance-based monocular vision approach for gaze estimation%基于表观特征的单目视觉算法实现的注视方向估计

    Institute of Scientific and Technical Information of China (English)

    张海秀; 葛宏志; 张晶

    2011-01-01

    As an important modality in Human - computer Interaction ( HCI),eye gaze provides rich information in communications.A Monocular Vision Approach (MVA) was proposed for gaze tracking under allowable head movement based on an appearance -based feature and Support Vector Regression (SVR).In MVA,only one commercial camera is used to capture a monocular face image as input,and the outputs are the head pose and gaze direction in sequence with respect to the camera coordinate system.This appearance -based feature employs a novel Directional Binary Pattern (DBP) to calculate the texture change relative to the pupil movement within the eye socket.In this method,the cropped two eye images are encoded into the high -dimensional DBP feature,which is fed into Support Vector Regression (SVR) to approximate the gaze mapping function.The 23 676 regression samples of 11 persons are clustered related to five head poses.Experimenta1 results show that this method can achieve the accuracy less than.%视线跟踪作为一种重要的人机接口模式,能够提供丰富的人机交互信息.提出了基于单目视觉的视线跟踪方法( Monocular Vision Approach,MVA).从眼部图像提取的表观特征,再经过支持向量回归( Support Vector Regression,SVR)计算实现可头部动作的注视方向估计.本方法仅用一个摄像机采集一副人脸图像作为输入数据,输出的计算结果是人的头部姿态和注视方向,以摄像机坐标系为参照系.采用的表观特征是基于方向二值模式( Directional Binary Pattern,DBP)算法,解析瞳孔在眼窝中运动引起的图像纹理变化.视线跟踪方法首先将双眼分割出来,并编码成高维的方向二值模式特征,最终通过支持向量回归作为匹配函数计算注视视角.共有11个人共23 676回归样本,按照姿态分成5个聚类集合.实验结果显示,基于本方法进行注视方向估计可以获得3°的测试误差.

  17. Depth measurement using monocular stereo vision system: aspect of spatial discretization

    Science.gov (United States)

    Xu, Zheng; Li, Chengjin; Zhao, Xunjie; Chen, Jiabo

    2010-11-01

    The monocular stereo vision system, consisting of single camera with controllable focal length, can be used in 3D reconstruction. Applying the system for 3D reconstruction, must consider effects caused by digital camera. There are two possible methods to make the monocular stereo vision system. First one the distance between the target object and the camera image plane is constant and lens moves. The second method assumes that the lens position is constant and the image plane moves in respect to the target. In this paper mathematical modeling of two approaches is presented. We focus on iso-disparity surfaces to define the discretization effect on the reconstructed space. These models are implemented and simulated on Matlab. The analysis is used to define application constrains and limitations of these methods. The results can be also used to enhance the accuracy of depth measurement.

  18. The design of a traffic environment prewarning system based on monocular vision%基于单目视觉的行车环境安全预警系统设计

    Institute of Scientific and Technical Information of China (English)

    邓筠; 沈文超; 徐建闽; 游峰

    2015-01-01

    This thesis aims to design a traffic environment prewarning system which is based on monocular vision and consists of three modules including CCD image acquisition module,driving environment detection module,and traffic environment danger alert module. The research focuses on new methods of traffic lane line extraction--preceding vehicle detection and traffic environment recognition,and also make description of the system hardware architecture and software process and algorithm,which can identify the highway traffic environment and warn drivers in case of dangerous situations. Experimental results show that the system can detect front lane and vehicles accurately to achieve the design effects.%文中设计了基于机器视觉的行车环境安全预警系统,采用包含视频图像采集、行车环境检测以及行车环境安全预警3个功能模块的系统结构,重点研究并提出了新的行车环境识别方法,包含车道线提取和前方车辆检测方法,并对系统硬件架构及软件流程和算法进行说明,实现高速公路行车环境的识别并进行危险警示。实验结果显示,系统能够准确地对前方车道线和车辆进行检测,实现设计效果。

  19. A Height Estimation Approach for Terrain Following Flights from Monocular Vision

    Directory of Open Access Journals (Sweden)

    Igor S. G. Campos

    2016-12-01

    Full Text Available In this paper, we present a monocular vision-based height estimation algorithm for terrain following flights. The impressive growth of Unmanned Aerial Vehicle (UAV usage, notably in mapping applications, will soon require the creation of new technologies to enable these systems to better perceive their surroundings. Specifically, we chose to tackle the terrain following problem, as it is still unresolved for consumer available systems. Virtually every mapping aircraft carries a camera; therefore, we chose to exploit this in order to use presently available hardware to extract the height information toward performing terrain following flights. The proposed methodology consists of using optical flow to track features from videos obtained by the UAV, as well as its motion information to estimate the flying height. To determine if the height estimation is reliable, we trained a decision tree that takes the optical flow information as input and classifies whether the output is trustworthy or not. The classifier achieved accuracies of 80 % for positives and 90 % for negatives, while the height estimation algorithm presented good accuracy.

  20. A Height Estimation Approach for Terrain Following Flights from Monocular Vision.

    Science.gov (United States)

    Campos, Igor S G; Nascimento, Erickson R; Freitas, Gustavo M; Chaimowicz, Luiz

    2016-12-06

    In this paper, we present a monocular vision-based height estimation algorithm for terrain following flights. The impressive growth of Unmanned Aerial Vehicle (UAV) usage, notably in mapping applications, will soon require the creation of new technologies to enable these systems to better perceive their surroundings. Specifically, we chose to tackle the terrain following problem, as it is still unresolved for consumer available systems. Virtually every mapping aircraft carries a camera; therefore, we chose to exploit this in order to use presently available hardware to extract the height information toward performing terrain following flights. The proposed methodology consists of using optical flow to track features from videos obtained by the UAV, as well as its motion information to estimate the flying height. To determine if the height estimation is reliable, we trained a decision tree that takes the optical flow information as input and classifies whether the output is trustworthy or not. The classifier achieved accuracies of 80 % for positives and 90 % for negatives, while the height estimation algorithm presented good accuracy.

  1. A Height Estimation Approach for Terrain Following Flights from Monocular Vision

    Science.gov (United States)

    Campos, Igor S. G.; Nascimento, Erickson R.; Freitas, Gustavo M.; Chaimowicz, Luiz

    2016-01-01

    In this paper, we present a monocular vision-based height estimation algorithm for terrain following flights. The impressive growth of Unmanned Aerial Vehicle (UAV) usage, notably in mapping applications, will soon require the creation of new technologies to enable these systems to better perceive their surroundings. Specifically, we chose to tackle the terrain following problem, as it is still unresolved for consumer available systems. Virtually every mapping aircraft carries a camera; therefore, we chose to exploit this in order to use presently available hardware to extract the height information toward performing terrain following flights. The proposed methodology consists of using optical flow to track features from videos obtained by the UAV, as well as its motion information to estimate the flying height. To determine if the height estimation is reliable, we trained a decision tree that takes the optical flow information as input and classifies whether the output is trustworthy or not. The classifier achieved accuracies of 80% for positives and 90% for negatives, while the height estimation algorithm presented good accuracy. PMID:27929424

  2. Cataract surgery: emotional reactions of patients with monocular versus binocular vision

    Directory of Open Access Journals (Sweden)

    Roberta Ferrari Marback

    2012-12-01

    Full Text Available PURPOSE: To analyze emotional reactions related to cataract surgery in two groups of patients (monocular vision - Group 1; binocular vision - Group 2. METHODS: A transversal comparative study was performed using a structured questionnaire from a previous exploratory study before cataract surgery. RESULTS: 206 patients were enrolled in the study, 96 individuals in Group 1 (69.3 ± 10.4 years and 110 in Group 2 (68.2 ± 10.2 years. Most patients in group 1 (40.6% and 22.7% of group 2, reported fear of surgery (p<0.001. The most important causes of fear were: possibility of blindness, ocular complications and death during surgery. The most prevalent feelings among the groups were doubts about good results and nervousness. CONCLUSION: Patients with monocular vision reported more fear and doubts related to surgical outcomes. Thus, it is necessary that phisycians considers such emotional reactions and invest more time than usual explaining the risks and the benefits of cataract surgery.Ouvir

  3. Monocular feature tracker for low-cost stereo vision control of an autonomous guided vehicle (AGV)

    Science.gov (United States)

    Pearson, Chris M.; Probert, Penelope J.

    1994-02-01

    We describe a monocular feature tracker (MFT), the first stage of a low cost stereoscopic vision system for use on an autonomous guided vehicle (AGV) in an indoor environment. The system does not require artificial markings or other beacons, but relies upon accurate knowledge of the AGV motion. Linear array cameras (LAC) are used to reduce the data and processing bandwidths. The limited information given by LAC require modelling of the expected features. We model an obstacle as a vertical line segment touching the floor, and can distinguish between these obstacles and most other clutter in an image sequence. Detection of these obstacles is sufficient information for local AGV navigation.

  4. 基于单目视觉的室内微型飞行器位姿估计与环境构建%Monocular Vision Based Motion Estimation of Indoor Micro Air Vehicles and Structure Recovery

    Institute of Scientific and Technical Information of China (English)

    郭力; 昂海松; 郑祥明

    2012-01-01

    Micro air vehicles (MAVs) need reliable attitude and position information in indoor environment. The measurements of onboard inertial measurement unit (IMU) sensors such as gyros and acce-larometers are corrupted by large accumulated errors, and GPS signal is unavailable in such situation. Therefore, a monocular vision based indoor MAV motion estimation and structure recovery method is presented. Firstly, the features are tracked by biological vision based matching algorithm through the image sequence, and the motion of camra is estimated by the five-point algorithm. In the indoor enviro-ment, the planar relationship is used to reduce the feature point dimentions from three to two. Then, these parameters are optimized by an local strategy to improve the motion estimation and structure recovery accuracy. The measurements of IMU sensors and vision module are fused with extended Kalman fileter. The attitude and position information of MAVs is estimated. The experiment shows that the method can reliably estimate the indoor motion of MAV in real-time, and the recovered enviroment information can be used for navigation of MAVs.%针对微型飞行嚣(Micro air vehicle,MAV)在室内飞行过程中无法获得GPS信号,而微型惯性单元(Inertial measurement unit,IMU)的陀螺仪和加速度计随机漂移误差较大,提出一种利用单目视觉估计微型飞行嚣位姿并构建室内环境的方法.在机载单目摄像机拍摄的序列图像中引入一种基于生物视觉的方法获得匹配特征点,并由五点算法获得帧间摄像机运动参数和特征点位置参数的初始解;利用平面关系将特征点的位置信息由三维降低到二维,给出一种局部优化方法求解摄像机运动参数和特征点位置参数的最大似然估计,提高位姿估计和环境构建的精度.最后通过扩展卡尔曼滤波方法融合IMU传感器和单目视觉测量信息解算出微型飞行器的位姿.实验结果表明,该方法能够实时可

  5. 基于单目视觉的跟驰车辆车距测量方法%Method of vehicle distance measurement for following car based on monocular vision

    Institute of Scientific and Technical Information of China (English)

    余厚云; 张为公

    2012-01-01

    为了解决结构化道路上跟驰车辆的防追尾碰撞问题,首先在对车辆制动模型进行分析的基础上得到了车辆制动距离的计算公式,进而计算出跟驰车辆与前方车辆之间的安全距离.然后,从针孔模型摄像机成像的基本原理出发,推导出基于图像中车道线消失点的车距测量公式.车距测量结果只与图像中的近视场点到摄像机的实际距离有关,无需对所有的摄像机参数进行标定,从而解决了单目视觉车距测量问题.最后,完成了不同距离处前方车辆的车距测量试验.试验结果表明,该方法的车距测量相对误差小于3%,具备了较高的检测精度,能够满足跟驰车辆防追尾碰撞的应用要求.%To solve the problem of rear collision avoidance for the following car on structural road, the formula of braking distance is obtained based on the analysis of the vehicle braking model, and the safety distance is then calculated accordingly. Then, using the basic theory of imaging of a pin-hole model camera, the formula of vehicle distance measurement is deduced based on the vanishing point of lane lines. The formula is related only to the actual distance between the camera and the point of near field of view without calibrating all of the camera parameters, and the vehicle distance measurement can be realized with monocular vision. Finally, experiments for the measurement are performed with the preceding vehicle at different positions. Experimental results demonstrate that the relative error of vehicle distance measurement is less than 3% and the precision can meet the application of collision avoidance for the following car.

  6. 基于单目视觉的障碍物定位和测量%Obstacle Detection and Measurement Based on Monocular Vision

    Institute of Scientific and Technical Information of China (English)

    王振; 王化明

    2015-01-01

    障碍物定位与测量是智能移动机器人自主运动的核心问题之一。研究了一种结合障碍物色彩属性和接触边缘属性的算法,通过单个视觉传感器实现平坦路面中障碍物的定位和测量。该算法以图像中已知路面范围的外观属性为基准对图像进行初步处理,依据障碍物和地面接触边缘属性对障碍物进行初步定位,在障碍物上选择区域,以该区域外观属性为基准对图像进行二次处理,得到障碍物在图像中占据范围,结合视觉传感器成像原理,对障碍物位置和尺寸进行标定和测量。以轮式移动机器人为实验平台,验证所提算法的可行性和精度,最终测得其定位误差为1.6%,测量误差为1.5%。%Obstacle detection and measurement is one of the key problems for the autonomous movement of intel igent mobile robot. This paper presents an algorithm based on the combination of the appearance and the contact edge which is used to detect and measure the obstacle on the flat surface using single visual sensor. In the algorithm the image is primary handled according to the ap ̄pearance property of known ground surface and the obstacle position defected according to the edge property of the contact area be ̄tween obstacle and ground, then the reference area on the obstacle is seleted and the image is handled again according to the ap ̄pearance property of the obstacle to get the position of the obstacle in the image,final y the obstacle detection and measurement are finished according to the principle of visual sensor. The effectiveness and accuracy of the algorithm is tested and verified on a wheeled mobile robot,the error of detection algorithm is about 5 %,while the error of measurement algorithm is about 1.89 %.

  7. Cataract surgery: emotional reactions of patients with monocular versus binocular vision Cirurgia de catarata: aspectos emocionais de pacientes com visão monocular versus binocular

    Directory of Open Access Journals (Sweden)

    Roberta Ferrari Marback

    2012-12-01

    Full Text Available PURPOSE: To analyze emotional reactions related to cataract surgery in two groups of patients (monocular vision - Group 1; binocular vision - Group 2. METHODS: A transversal comparative study was performed using a structured questionnaire from a previous exploratory study before cataract surgery. RESULTS: 206 patients were enrolled in the study, 96 individuals in Group 1 (69.3 ± 10.4 years and 110 in Group 2 (68.2 ± 10.2 years. Most patients in group 1 (40.6% and 22.7% of group 2, reported fear of surgery (pOBJETIVO: Verificar reações emocionais relacionadas à cirurgia de catarata entre pacientes com visão monocular (Grupo 1 e binocular (Grupo 2. MÉTODOS: Foi realizado um estudo tranversal, comparativo por meio de um questionário estruturado respondido por pacientes antes da cirurgia de catarata. RESULTADOS: A amostra foi composta de 96 pacientes no Grupo 1 (69.3 ± 10.4 anos e 110 no Grupo 2 (68.2 ± 10.2 anos. Consideravam apresentar medo da cirugia 40.6% do Grupo 1 e 22.7% do Grupo 2 (p<0.001 e entre as principais causas do medo, a possibilidade de perda da visão, complicações cirúrgicas e a morte durante o procedimento foram apontadas. Os sentimentos mais comuns entre os dois grupos foram dúvidas a cerca dos resultados da cirurgia e o nervosismo diante do procedimento. CONCLUSÃO: Pacientes com visão monocular apresentaram mais medo e dúvidas relacionadas à cirurgia de catarata comparados com aqueles com visão binocular. Portanto, é necessário que os médicos considerem estas reações emocionais e invistam mais tempo para esclarecer os riscos e benefícios da cirurgia de catarata.

  8. Monocular Vision System for Fixed Altitude Flight of Unmanned Aerial Vehicles.

    Science.gov (United States)

    Huang, Kuo-Lung; Chiu, Chung-Cheng; Chiu, Sheng-Yi; Teng, Yao-Jen; Hao, Shu-Sheng

    2015-07-13

    The fastest and most economical method of acquiring terrain images is aerial photography. The use of unmanned aerial vehicles (UAVs) has been investigated for this task. However, UAVs present a range of challenges such as flight altitude maintenance. This paper reports a method that combines skyline detection with a stereo vision algorithm to enable the flight altitude of UAVs to be maintained. A monocular camera is mounted on the downside of the aircraft's nose to collect continuous ground images, and the relative altitude is obtained via a stereo vision algorithm from the velocity of the UAV. Image detection is used to obtain terrain images, and to measure the relative altitude from the ground to the UAV. The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images. A forward-looking camera is mounted on the upside of the aircraft's nose. In combination with the skyline detection algorithm, this helps the aircraft to maintain a stable flight pattern. Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path.

  9. Monocular Vision System for Fixed Altitude Flight of Unmanned Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Kuo-Lung Huang

    2015-07-01

    Full Text Available The fastest and most economical method of acquiring terrain images is aerial photography. The use of unmanned aerial vehicles (UAVs has been investigated for this task. However, UAVs present a range of challenges such as flight altitude maintenance. This paper reports a method that combines skyline detection with a stereo vision algorithm to enable the flight altitude of UAVs to be maintained. A monocular camera is mounted on the downside of the aircraft’s nose to collect continuous ground images, and the relative altitude is obtained via a stereo vision algorithm from the velocity of the UAV. Image detection is used to obtain terrain images, and to measure the relative altitude from the ground to the UAV. The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images. A forward-looking camera is mounted on the upside of the aircraft’s nose. In combination with the skyline detection algorithm, this helps the aircraft to maintain a stable flight pattern. Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path.

  10. Indoor monocular mobile robot navigation based on color landmarks

    Institute of Scientific and Technical Information of China (English)

    LUO Yuan; ZHANG Bai-sheng; ZHANG Yi; LI Ling

    2009-01-01

    A robot landmark navigation system based on monocular camera was researched theoretically and experimentally. First the landmark setting and its data structure in programming was given; then the coordinates of them getting by robot and global localization of the robot was described; finally experiments based on Pioneer III mobile robot show that this system can work well at different topographic situation without lose of signposts.

  11. Visual system plasticity in mammals: the story of monocular enucleation-induced vision loss.

    Science.gov (United States)

    Nys, Julie; Scheyltjens, Isabelle; Arckens, Lutgarde

    2015-01-01

    The groundbreaking work of Hubel and Wiesel in the 1960's on ocular dominance plasticity instigated many studies of the visual system of mammals, enriching our understanding of how the development of its structure and function depends on high quality visual input through both eyes. These studies have mainly employed lid suturing, dark rearing and eye patching applied to different species to reduce or impair visual input, and have created extensive knowledge on binocular vision. However, not all aspects and types of plasticity in the visual cortex have been covered in full detail. In that regard, a more drastic deprivation method like enucleation, leading to complete vision loss appears useful as it has more widespread effects on the afferent visual pathway and even on non-visual brain regions. One-eyed vision due to monocular enucleation (ME) profoundly affects the contralateral retinorecipient subcortical and cortical structures thereby creating a powerful means to investigate cortical plasticity phenomena in which binocular competition has no vote.In this review, we will present current knowledge about the specific application of ME as an experimental tool to study visual and cross-modal brain plasticity and compare early postnatal stages up into adulthood. The structural and physiological consequences of this type of extensive sensory loss as documented and studied in several animal species and human patients will be discussed. We will summarize how ME studies have been instrumental to our current understanding of the differentiation of sensory systems and how the structure and function of cortical circuits in mammals are shaped in response to such an extensive alteration in experience. In conclusion, we will highlight future perspectives and the clinical relevance of adding ME to the list of more longstanding deprivation models in visual system research.

  12. Acute Myeloid Leukemia Relapse Presenting as Complete Monocular Vision Loss due to Optic Nerve Involvement

    Directory of Open Access Journals (Sweden)

    Shyam A. Patel

    2016-01-01

    Full Text Available Acute myeloid leukemia (AML involvement of the central nervous system is relatively rare, and detection of leptomeningeal disease typically occurs only after a patient presents with neurological symptoms. The case herein describes a 48-year-old man with relapsed/refractory AML of the mixed lineage leukemia rearrangement subtype, who presents with monocular vision loss due to leukemic eye infiltration. MRI revealed right optic nerve sheath enhancement and restricted diffusion concerning for nerve ischemia and infarct from hypercellularity. Cerebrospinal fluid (CSF analysis showed a total WBC count of 81/mcl with 96% AML blasts. The onset and progression of visual loss were in concordance with rise in peripheral blood blast count. A low threshold for diagnosis of CSF involvement should be maintained in patients with hyperleukocytosis and high-risk cytogenetics so that prompt treatment with whole brain radiation and intrathecal chemotherapy can be delivered. This case suggests that the eye, as an immunoprivileged site, may serve as a sanctuary from which leukemic cells can resurge and contribute to relapsed disease in patients with high-risk cytogenetics.

  13. TTC Calculation and Characteristic Parameters Study Based on Monocular Vision%基于单目视觉的车间TTC计算及追尾危险工况特征参数研究

    Institute of Scientific and Technical Information of China (English)

    许宇能; 朱西产; 李霖; 马志雄

    2014-01-01

    In order to study the characteristic parameters of the cases of near -crash, this paper focus on data extraction and evaluation of rear -end near-crash cases which were collected in the last five years .First, Time to Collistion(TTC) during the cases was calculated using merely information from monocular vision .Then, statistical analysis was conducted for the parameters including TTC of normal state of following vehicles , TTC and velocity of emergency braking , TTC of the most dangerous moment .Experiment results show that 95 percent of rear-end near-crashes happen below 45 km/h, and the average of braking deceleration is 0.51g, the TTC of normal following, start-braking moment and most dangerous moment are 2.9s, 2.0s, 1.0s respectively.%为了研究车辆追尾危险工况的特征参数,本文针对最近五年来采集到的追尾危险工况数据进行特征参数提取和分析.首先利用单目图像信息,计算危险发生过程中车辆间的碰撞时间( TTC),然后对车辆正常跟车状态下TTC值、开始紧急制动时的速度、TTC值、制动减速度和最危险时刻TTC值等参数进行统计分析.实验结果显示,有95%的追尾危险发生在45 km/h以下,驾驶员制动时产生的制动减速度均值为0.51g,驾驶员正常跟车时、开始制动时、最危险时的TTC值分别为2.9s,2.0s,1.0s.

  14. Mobile Robot Simultaneous Localization and Mapping Based on a Monocular Camera

    Directory of Open Access Journals (Sweden)

    Songmin Jia

    2016-01-01

    Full Text Available This paper proposes a novel monocular vision-based SLAM (Simultaneous Localization and Mapping algorithm for mobile robot. In this proposed method, the tracking and mapping procedures are split into two separate tasks and performed in parallel threads. In the tracking thread, a ground feature-based pose estimation method is employed to initialize the algorithm for the constraint moving of the mobile robot. And an initial map is built by triangulating the matched features for further tracking procedure. In the mapping thread, an epipolar searching procedure is utilized for finding the matching features. A homography-based outlier rejection method is adopted for rejecting the mismatched features. The indoor experimental results demonstrate that the proposed algorithm has a great performance on map building and verify the feasibility and effectiveness of the proposed algorithm.

  15. Effects of brief daily periods of unrestricted vision during early monocular form deprivation on development of visual area 2.

    Science.gov (United States)

    Zhang, Bin; Tao, Xiaofeng; Wensveen, Janice M; Harwerth, Ronald S; Smith, Earl L; Chino, Yuzo M

    2011-09-14

    Providing brief daily periods of unrestricted vision during early monocular form deprivation reduces the depth of amblyopia. To gain insights into the neural basis of the beneficial effects of this treatment, the binocular and monocular response properties of neurons were quantitatively analyzed in visual area 2 (V2) of form-deprived macaque monkeys. Beginning at 3 weeks of age, infant monkeys were deprived of clear vision in one eye for 12 hours every day until 21 weeks of age. They received daily periods of unrestricted vision for 0, 1, 2, or 4 hours during the form-deprivation period. After behavioral testing to measure the depth of the resulting amblyopia, microelectrode-recording experiments were conducted in V2. The ocular dominance imbalance away from the affected eye was reduced in the experimental monkeys and was generally proportional to the reduction in the depth of amblyopia in individual monkeys. There were no interocular differences in the spatial properties of V2 neurons in any subject group. However, the binocular disparity sensitivity of V2 neurons was significantly higher and binocular suppression was lower in monkeys that had unrestricted vision. The decrease in ocular dominance imbalance in V2 was the neuronal change most closely associated with the observed reduction in the depth of amblyopia. The results suggest that the degree to which extrastriate neurons can maintain functional connections with the deprived eye (i.e., reducing undersampling for the affected eye) is the most significant factor associated with the beneficial effects of brief periods of unrestricted vision.

  16. Implementation of vision based 2-DOF underwater Manipulator

    Directory of Open Access Journals (Sweden)

    Geng Jinpeng

    2015-01-01

    Full Text Available Manipulator is of vital importance to the remotely operated vehicle (ROV, especially when it works in the nuclear reactor pool. Two degrees of freedom (2-DOF underwater manipulator is designed to the ROV, which is composed of control cabinet, buoyancy module, propellers, depth gauge, sonar, a monocular camera and other attitude sensors. The manipulator can be used to salvage small parts like bolts and nuts to accelerate the progress of the overhaul. It can move in the vertical direction alone through the control of the second joint, and can grab object using its unique designed gripper. A monocular vision based localization algorithm is applied to help the manipulator work independently and intelligently. Eventually, field experiment is conducted in the swimming pool to verify the effectiveness of the manipulator and the monocular vision based algorithm.

  17. A low cost PSD-based monocular motion capture system

    Science.gov (United States)

    Ryu, Young Kee; Oh, Choonsuk

    2007-10-01

    This paper describes a monocular PSD-based motion capture sensor to employ with commercial video game systems such as Microsoft's XBOX and Sony's Playstation II. The system is compact, low-cost, and only requires a one-time calibration at the factory. The system includes a PSD(Position Sensitive Detector) and active infrared (IR) LED markers that are placed on the object to be tracked. The PSD sensor is placed in the focal plane of a wide-angle lens. The micro-controller calculates the 3D position of the markers using only the measured intensity and the 2D position on the PSD. A series of experiments were performed to evaluate the performance of our prototype system. From the experimental results we see that the proposed system has the advantages of the compact size, the low cost, the easy installation, and the high frame rates to be suitable for high speed motion tracking in games.

  18. Loop Closure Detection Algorithm Based on Monocular Vision Using Visual Dictionary%基于视觉词典的单目视觉闭环检测算法

    Institute of Scientific and Technical Information of China (English)

    梁志伟; 陈燕燕; 朱松豪; 高翔; 徐国政

    2013-01-01

    Aiming at the problem of loop closure detection in monocular simultaneous localization and mapping for mobile robots,a detection algorithm based on visual dictionary (VD) is presented.Firstly,feature extraction is performed for each required image using SURF methods.Subsequently,a fuzzy K-means algorithm is employed to cluster these visual feature vectors into visual words based on VD which is constructed online.To precisely represent the similarities between each visual word and corresponding local visual features,Gaussian mixture model is proposed to learn the probability model of every visual word in bags of visual words.Consequently,every image can be denoted as a probabilistic vector of VD,and thus the similarities between any two images can be computed based on vector inner product.To guarantee the continuity of the closed-loop detection,a Bayesian filter method is applied to fuse historical closed-loop detection information and the obtained similarities to calculate the posterior probability distribution of closed-loop hypothesis.Furthermore,two memory management mechanisms,shallow memory and deep memory,are introduced to improve the process speed of the proposed algorithm.The experimental results demonstrate the validity of the proposed approach.%针对移动机器人单目视觉同步定位与地图构建中的闭环检测问题,文中设计一种基于视觉词典的闭环检测算法.算法对采集的每帧图像通过SURF进行特征提取,应用模糊K均值算法对检测的视觉特征向量进行分类,在线构建表征图像的视觉词典.为精确表征局部视觉特征与视觉单词间的相似关联,利用混合高斯模型建立视觉词典中的每一视觉单词的概率模型,实现图像基于视觉词典的概率向量表示,通过向量的内积来计算图像间的相似度.为保证闭环检测的成功率,应用贝叶斯滤波融合历史闭环检测与相似度信息来计算闭环假设的后验概率分布.另外,引入浅层

  19. Monocular zones in stereoscopic scenes: A useful source of information for human binocular vision?

    Science.gov (United States)

    Harris, Julie M.

    2010-02-01

    When an object is closer to an observer than the background, the small differences between right and left eye views are interpreted by the human brain as depth. This basic ability of the human visual system, called stereopsis, lies at the core of all binocular three-dimensional (3-D) perception and related technological display development. To achieve stereopsis, it is traditionally assumed that corresponding locations in the right and left eye's views must first be matched, then the relative differences between right and left eye locations are used to calculate depth. But this is not the whole story. At every object-background boundary, there are regions of the background that only one eye can see because, in the other eye's view, the foreground object occludes that region of background. Such monocular zones do not have a corresponding match in the other eye's view and can thus cause problems for depth extraction algorithms. In this paper I will discuss evidence, from our knowledge of human visual perception, illustrating that monocular zones do not pose problems for our human visual systems, rather, our visual systems can extract depth from such zones. I review the relevant human perception literature in this area, and show some recent data aimed at quantifying the perception of depth from monocular zones. The paper finishes with a discussion of the potential importance of considering monocular zones, for stereo display technology and depth compression algorithms.

  20. Moving target geolocation for micro air vehicles based on monocular vision%基于单目视觉的微型飞行器移动目标定位方法

    Institute of Scientific and Technical Information of China (English)

    郭力; 昂海松; 郑祥明

    2012-01-01

    针对目标在地形高度未知环境中移动的情况,给出一种利用微型飞行器机载单目摄像机进行目标定位的方法.首先,借助光流直方图从当前图像帧中提取出移动目标局部区域内的背景特征点;然后,结合机载微机电系统(micro electro mechanical system,MEMS)/全球定位系统(global positioning system,GPS)传感器测量的飞行器位姿和空间平面点成像的单应变换关系,在期望值最大化算法中将背景特征点分类为辅助平面点和非辅助平面点,并估计辅助平面到摄像机光心的距离参数和法矢量参数,从而确定移动目标所处辅助平面的空间平面方程;最后,联立求解目标视线方程和辅助平面方程获得交点坐标,转换到惯性系下完成移动目标的地理定位.实验结果表明,当微型飞行器飞行高度为100 m时,操作人员单次点击移动目标的定位误差在15 m以内.%Aiming at the movement of the targets in unknown altitude terrain, a monocular camera based target geolocation method for micro air vehicles (MAV) is presented. Firstly, the optical flow histgram algorithm extracts background features in the target's local region. Secondly, these features are clustered into two possible classes including aided plane features and non-aided plane features by the expectation maximization algorithm, in which the homography relationship between MAV's flight status measured by onboard micro electro mechanical systems (MEMS)/ global positioning system (GPS) sensors and planar is used. Meanwile, the normal vector of aided plane and the distance between the camera and the plane are estimated. Then the aided plane equation can be establised. Finally, the moving taregt can be geolocated by calculating the intersection of target's sight line and aided plane in inertial frame. Experimental results show that this method can instantaneously geolocate the moving target by operator's single click and the error can reach less than

  1. Vision Based SLAM in Dynamic Scenes

    Science.gov (United States)

    2012-12-20

    understanding [20), or to improve the system accu- racy and robustness, such as ’ loop closure’ [16), ’re- localization’ [36), and dense depth map...to combine the advantages of omnidirection vision [37] and monocular vision. Castle et al. [5] used multiple cameras distributed freely in a...T. Drummond. Scalable monocular SlAM. In IEEE Proc. of CVPR, volume 1, pages 469-476, 2006. (13) G. Golub. Nume rical methods for solving linea r

  2. Autocalibrating vision guided navigation of unmanned air vehicles via tactical monocular cameras in GPS denied environments

    Science.gov (United States)

    Celik, Koray

    This thesis presents a novel robotic navigation strategy by using a conventional tactical monocular camera, proving the feasibility of using a monocular camera as the sole proximity sensing, object avoidance, mapping, and path-planning mechanism to fly and navigate small to medium scale unmanned rotary-wing aircraft in an autonomous manner. The range measurement strategy is scalable, self-calibrating, indoor-outdoor capable, and has been biologically inspired by the key adaptive mechanisms for depth perception and pattern recognition found in humans and intelligent animals (particularly bats), designed to assume operations in previously unknown, GPS-denied environments. It proposes novel electronics, aircraft, aircraft systems, systems, and procedures and algorithms that come together to form airborne systems which measure absolute ranges from a monocular camera via passive photometry, mimicking that of a human-pilot like judgement. The research is intended to bridge the gap between practical GPS coverage and precision localization and mapping problem in a small aircraft. In the context of this study, several robotic platforms, airborne and ground alike, have been developed, some of which have been integrated in real-life field trials, for experimental validation. Albeit the emphasis on miniature robotic aircraft this research has been tested and found compatible with tactical vests and helmets, and it can be used to augment the reliability of many other types of proximity sensors.

  3. Visual-tracking-based robot vision system

    Science.gov (United States)

    Deng, Keqiang; Wilson, Joseph N.; Ritter, Gerhard X.

    1992-11-01

    There are two kinds of depth perception for robot vision systems: quantitative and qualitative. The first one can be used to reconstruct the visible surfaces numerically while the second to describe the visible surfaces qualitatively. In this paper, we present a qualitative vision system suitable for intelligent robots. The goal of such a system is to perceive depth information qualitatively using monocular 2-D images. We first establish a set of propositions relating depth information, such as 3-D orientation and distance, to the changes of image region caused by camera motion. We then introduce an approximation-based visual tracking system. Given an object, the tracking system tracks its image while moving the camera in a way dependent upon the particular depth property to be perceived. Checking the data generated by the tracking system with our propositions provides us the depth information about the object. The visual tracking system can track image regions in real-time even as implemented on a PC AT clone machine, and mobile robots can naturally provide the inputs to our visual tracking system, therefore, we are able to construct a real-time, cost effective, monocular, qualitative and 3-dimensional robot vision system. To verify our idea, we present examples of perception of planar surface orientation, distance, size, dimensionality and convexity/concavity.

  4. A method of real-time detection for distant moving obstacles by monocular vision

    Science.gov (United States)

    Jia, Bao-zhi; Zhu, Ming

    2013-12-01

    In this paper, we propose an approach for detection of distant moving obstacles like cars and bicycles by a monocular camera to cooperate with ultrasonic sensors in low-cost condition. We are aiming at detecting distant obstacles that move toward our autonomous navigation car in order to give alarm and keep away from them. Method of frame differencing is applied to find obstacles after compensation of camera's ego-motion. Meanwhile, each obstacle is separated from others in an independent area and given a confidence level to indicate whether it is coming closer. The results on an open dataset and our own autonomous navigation car have proved that the method is effective for detection of distant moving obstacles in real-time.

  5. Vision-based interaction

    CERN Document Server

    Turk, Matthew

    2013-01-01

    In its early years, the field of computer vision was largely motivated by researchers seeking computational models of biological vision and solutions to practical problems in manufacturing, defense, and medicine. For the past two decades or so, there has been an increasing interest in computer vision as an input modality in the context of human-computer interaction. Such vision-based interaction can endow interactive systems with visual capabilities similar to those important to human-human interaction, in order to perceive non-verbal cues and incorporate this information in applications such

  6. Toward 3D Reconstruction of Outdoor Scenes Using an MMW Radar and a Monocular Vision Sensor

    Directory of Open Access Journals (Sweden)

    Ghina El Natour

    2015-10-01

    Full Text Available In this paper, we introduce a geometric method for 3D reconstruction of the exterior environment using a panoramic microwave radar and a camera. We rely on the complementarity of these two sensors considering the robustness to the environmental conditions and depth detection ability of the radar, on the one hand, and the high spatial resolution of a vision sensor, on the other. Firstly, geometric modeling of each sensor and of the entire system is presented. Secondly, we address the global calibration problem, which consists of finding the exact transformation between the sensors’ coordinate systems. Two implementation methods are proposed and compared, based on the optimization of a non-linear criterion obtained from a set of radar-to-image target correspondences. Unlike existing methods, no special configuration of the 3D points is required for calibration. This makes the methods flexible and easy to use by a non-expert operator. Finally, we present a very simple, yet robust 3D reconstruction method based on the sensors’ geometry. This method enables one to reconstruct observed features in 3D using one acquisition (static sensor, which is not always met in the state of the art for outdoor scene reconstruction. The proposed methods have been validated with synthetic and real data.

  7. Monocular and binocular development in children with albinism, infantile nystagmus syndrome and normal vision

    NARCIS (Netherlands)

    Huurneman, B.; Boonstra, F.N.

    2013-01-01

    Background/aims: To compare interocular acuity differences, crowding ratios, and binocular summation ratios in 4- to 8-year-old children with albinism (nn=n16), children with infantile nystagmus syndrome (nn=n10), and children with normal vision (nn=n72). Methods: Interocular acuity differences and

  8. Monocular and binocular development in children with albinism, infantile nystagmus syndrome, and normal vision

    NARCIS (Netherlands)

    Huurneman, B.; Boonstra, F.N.

    2013-01-01

    Abstract Background/aims: To compare interocular acuity differences, crowding ratios, and binocular summation ratios in 4- to 8-year-old children with albinism (n = 16), children with infantile nystagmus syndrome (n = 10), and children with normal vision (n = 72). Methods: Interocular acuity differe

  9. Monocular and binocular development in children with albinism, infantile nystagmus syndrome and normal vision

    NARCIS (Netherlands)

    Huurneman, B.; Boonstra, F.N.

    2013-01-01

    Background/aims: To compare interocular acuity differences, crowding ratios, and binocular summation ratios in 4- to 8-year-old children with albinism (nn=n16), children with infantile nystagmus syndrome (nn=n10), and children with normal vision (nn=n72). Methods: Interocular acuity differences and

  10. Monocular and binocular development in children with albinism, infantile nystagmus syndrome, and normal vision

    NARCIS (Netherlands)

    Huurneman, B.; Boonstra, F.N.

    2013-01-01

    Abstract Background/aims: To compare interocular acuity differences, crowding ratios, and binocular summation ratios in 4- to 8-year-old children with albinism (n = 16), children with infantile nystagmus syndrome (n = 10), and children with normal vision (n = 72). Methods: Interocular acuity

  11. A Re-Evaluation of Achromatic Spatiotemporal Vision: Nonoriented Filters are Monocular, they Adapt and Can be Used for Decision-Making at High Flicker Speeds

    Directory of Open Access Journals (Sweden)

    Tim S. Meese

    2011-05-01

    Full Text Available Masking, adaptation, and summation paradigms have been used to investigate the characteristics of early spatiotemporal vision. Each has been taken to provide evidence for (i oriented and (ii nonoriented spatial filtering mechanisms. However, subsequent findings suggest that the evidence for nonoriented mechanisms has been misinterpreted: possibly, those experiments revealed the characteristics of suppression (e.g., gain control not excitation, or merely the isotropic subunits of the oriented detecting-mechanisms. To shed light on this, we used all three paradigms to focus on the “high-speed” corner of spatiotemporal vision (low spatial frequency, high temporal frequency where cross-oriented achromatic effects are greatest. We used flickering Gabor patches as targets and a 2IFC procedure for monocular, binocular and dichoptic stimulus presentations. To account for our results we devised a simple model involving an isotropic monocular filter-stage feeding orientation-tuned binocular filters. Both filter stages are adaptable and their outputs are available to the decision-stage following nonlinear contrast transduction. However, the monocular isotropic filters adapt only to high-speed stimuli—consistent with a magnocellular sub-cortical substrate—and benefit decision making only for high-speed stimuli. According to this model, the visual processes revealed by masking, adaptation and summation are related but not identical.

  12. 基于单目视觉的并联机器人末端位姿检测%Position and Orientation Measurement of Parallel Robot Based on Monocular Vision

    Institute of Scientific and Technical Information of China (English)

    丁雅斌; 梅江平; 张文昌; 刘晓利

    2014-01-01

    高效、准确地检测机器人末端位姿误差是实现运动学标定的关键环节。提出一种基于单目摄像机拍摄立体靶标序列图像信息的末端执行器6维位姿误差辨识方法,构造具有平行四边形几何约束的四个空间特征点,并以平行四边形的两个消隐点为约束,建立空间刚体位姿与其二维图像映射关系模型,实现末端位姿的精确定位,然后以Delta高速并联机器人为对象,进行了运动学标定试验,验证该方法的有效性,为这类机器人低成本、快速、在线运动学标定提供重要的理论与技术基础。%The robot pose errors detection is a key step to realize the kinematic calibration. The six-dimensional geometrical errors detection using a single CCD camera and elaborately designed targets is proposed. A model of rigid body displacement and its 2D image mapping, which is constructed based on 4 spatial features and 2 vanishing points of a parallelogram geometric constraint, can be used to achieve precise positioning of the position and pose of the end-effector. By taking a Delta robot as a demonstrator, experiments of kinematic calibration will be carried out to verify the validity and effectiveness of the proposed approach. The outcomes will lay a solid theoretical foundation for the low-cost and fast kinematic calibration of the robot.

  13. A comparison of low-cost monocular vision techniques for pothole distance estimation

    CSIR Research Space (South Africa)

    Nienaber, S

    2015-12-01

    Full Text Available to these obstacles in the range of 5 m to 30 m. We provide an empirical evaluation of the accuracy of these approaches under various conditions, and make recommendations for when each approach is most suitable. The approaches are based on the pinhole camera model...

  14. Amodal completion with background determines depth from monocular gap stereopsis.

    Science.gov (United States)

    Grove, Philip M; Ben Sachtler, W L; Gillam, Barbara J

    2006-10-01

    Grove, Gillam, and Ono [Grove, P. M., Gillam, B. J., & Ono, H. (2002). Content and context of monocular regions determine perceived depth in random dot, unpaired background and phantom stereograms. Vision Research, 42, 1859-1870] reported that perceived depth in monocular gap stereograms [Gillam, B. J., Blackburn, S., & Nakayama, K. (1999). Stereopsis based on monocular gaps: Metrical encoding of depth and slant without matching contours. Vision Research, 39, 493-502] was attenuated when the color/texture in the monocular gap did not match the background. It appears that continuation of the gap with the background constitutes an important component of the stimulus conditions that allow a monocular gap in an otherwise binocular surface to be responded to as a depth step. In this report we tested this view using the conventional monocular gap stimulus of two identical grey rectangles separated by a gap in one eye but abutting to form a solid grey rectangle in the other. We compared depth seen at the gap for this stimulus with stimuli that were identical except for two additional small black squares placed at the ends of the gap. If the squares were placed stereoscopically behind the rectangle/gap configuration (appearing on the background) they interfered with the perceived depth at the gap. However when they were placed in front of the configuration this attenuation disappeared. The gap and the background were able under these conditions to complete amodally.

  15. Vision Based Geo Navigation Information Retreival

    Directory of Open Access Journals (Sweden)

    Asif Khan

    2016-01-01

    Full Text Available In order to derive the three-dimensional camera position from the monocular camera vision, a geo-reference database is needed. Floor plan is a ubiquitous geo-reference database that every building refers to it during construction and facility maintenance. Comparing with other popular geo-reference database such as geo-tagged photos, the generation, update and maintenance of floor plan database does not require costly and time consuming survey tasks. In vision based methods, the camera needs special attention. In contrast to other sensors, vision sensors typically yield vast information that needs complex strategies to permit use in real-time and on computationally con-strained platforms. This research work show that map-based visual odometer strategy derived from a state-of-the-art structure-from-motion framework is particularly suitable for locally stable, pose controlled flight. Issues concerning drifts and robustness are analyzed and discussed with respect to the original framework. Additionally, various usage of localization algorithm in view of vision has been proposed here. Though, a noteworthy downside with vision-based algorithms is the absence of robustness. The greater parts of the methodologies are delicate to scene varieties (like season or environment changes because of the way that they utilize the Sum of Squared Differences (SSD. To stop that, we utilize the Mutual Information which is exceptionally vigorous toward global and local scene varieties. On the other hand, dense methodologies are frequently identified with drift drawbacks. Here, attempt to take care of this issue by utilizing geo-referenced pictures. The algorithm of localization has been executed and experimental results are available. Vision sensors possess the potential to extract information about the surrounding environment and determine the locations of features or points of interest. Having mapped out landmarks in an unknown environment, subsequent observations

  16. Capturing age-related changes in functional contrast sensitivity with decreasing light levels in monocular and binocular vision

    OpenAIRE

    Gillespie-Gallery, H.; Konstantakopoulou, E.; HARLOW, J.A.; Barbur, J. L.

    2013-01-01

    Purpose: It is challenging to separate the effects of normal aging of the retina and visual pathways independently from optical factors, decreased retinal illuminance and early stage disease. This study determined limits to describe the effect of light level on normal, age-related changes in monocular and binocular functional contrast sensitivity. Methods: 95 participants aged 20 to 85 were recruited. Contrast thresholds for correct orientation discrimination of the gap in a Landolt C opt...

  17. Neural correlates of monocular and binocular depth cues based on natural images: a LORETA analysis.

    Science.gov (United States)

    Fischmeister, Florian Ph S; Bauer, Herbert

    2006-10-01

    Functional imaging studies investigating perception of depth rely solely on one type of depth cue based on non-natural stimulus material. To overcome these limitations and to provide a more realistic and complete set of depth cues natural stereoscopic images were used in this study. Using slow cortical potentials and source localization we aimed to identify the neural correlates of monocular and binocular depth cues. This study confirms and extends functional imaging studies, showing that natural images provide a good, reliable, and more realistic alternative to artificial stimuli, and demonstrates the possibility to separate the processing of different depth cues.

  18. Spatial Testing of Dynamic Process and Analysis Technique of Intelligent AC Contactors Based on the Monocular Vision Technology%基于单目视觉技术的智能交流接触器三维动态测试与分析技术

    Institute of Scientific and Technical Information of China (English)

    陈德为; 庄煜祺; 张培铭; 严俊奇

    2014-01-01

    Based on the intelligent AC contactor control system and the auxiliary plane mirror imaging system, a special dynamic process of intelligent AC contactor testing method is proposed by collecting sequence images of the dynamic process of AC contactors with a monocular high-speed camera. By detecting and identifying feature points on moving targets of AC contactors from the image sequence, and dynamically tracking feature point position changes, the action mechanism with dynamic process of intelligent AC contactors is comprehensively tested and analyzed. The measuring technique and the analysis method have far-reaching significance for intelligent control and prototypeoptimization design of AC contactors.%在智能交流接触器智能控制系统和平面镜辅助成像技术的基础上,提出了基于单目高速摄像机采集智能交流接触器动态过程的序列图像,进行智能交流接触器三维动态特性测试的方法。从图像序列中检测识别智能交流接触器运动部件的特征标记点,动态跟踪特征标记点的位姿,从而对智能交流接触器动作机构动态过程进行全方位的测试与分析。该测试技术与分析方法对智能交流接触器运动的智能控制、样机优化设计的研究意义重大。

  19. A Robust Approach for a Filter-Based Monocular Simultaneous Localization and Mapping (SLAM System

    Directory of Open Access Journals (Sweden)

    Antoni Grau

    2013-07-01

    Full Text Available Simultaneous localization and mapping (SLAM is an important problem to solve in robotics theory in order to build truly autonomous mobile robots. This work presents a novel method for implementing a SLAM system based on a single camera sensor. The SLAM with a single camera, or monocular SLAM, is probably one of the most complex SLAM variants. In this case, a single camera, which is freely moving through its environment, represents the sole sensor input to the system. The sensors have a large impact on the algorithm used for SLAM. Cameras are used more frequently, because they provide a lot of information and are well adapted for embedded systems: they are light, cheap and power-saving. Nevertheless, and unlike range sensors, which provide range and angular information, a camera is a projective sensor providing only angular measurements of image features. Therefore, depth information (range cannot be obtained in a single step. In this case, special techniques for feature system-initialization are needed in order to enable the use of angular sensors (as cameras in SLAM systems. The main contribution of this work is to present a novel and robust scheme for incorporating and measuring visual features in filtering-based monocular SLAM systems. The proposed method is based in a two-step technique, which is intended to exploit all the information available in angular measurements. Unlike previous schemes, the values of parameters used by the initialization technique are derived directly from the sensor characteristics, thus simplifying the tuning of the system. The experimental results show that the proposed method surpasses the performance of previous schemes.

  20. A robust approach for a filter-based monocular simultaneous localization and mapping (SLAM) system.

    Science.gov (United States)

    Munguía, Rodrigo; Castillo-Toledo, Bernardino; Grau, Antoni

    2013-07-03

    Simultaneous localization and mapping (SLAM) is an important problem to solve in robotics theory in order to build truly autonomous mobile robots. This work presents a novel method for implementing a SLAM system based on a single camera sensor. The SLAM with a single camera, or monocular SLAM, is probably one of the most complex SLAM variants. In this case, a single camera, which is freely moving through its environment, represents the sole sensor input to the system. The sensors have a large impact on the algorithm used for SLAM. Cameras are used more frequently, because they provide a lot of information and are well adapted for embedded systems: they are light, cheap and power-saving. Nevertheless, and unlike range sensors, which provide range and angular information, a camera is a projective sensor providing only angular measurements of image features. Therefore, depth information (range) cannot be obtained in a single step. In this case, special techniques for feature system-initialization are needed in order to enable the use of angular sensors (as cameras) in SLAM systems. The main contribution of this work is to present a novel and robust scheme for incorporating and measuring visual features in filtering-based monocular SLAM systems. The proposed method is based in a two-step technique, which is intended to exploit all the information available in angular measurements. Unlike previous schemes, the values of parameters used by the initialization technique are derived directly from the sensor characteristics, thus simplifying the tuning of the system. The experimental results show that the proposed method surpasses the performance of previous schemes.

  1. Vision-based Vehicle Detection Survey

    Directory of Open Access Journals (Sweden)

    Alex David S

    2016-03-01

    Full Text Available Nowadays thousands of drivers and passengers were losing their lives every year on road accident, due to deadly crashes between more than one vehicle. There are number of many research focuses were dedicated to the development of intellectual driver assistance systems and autonomous vehicles over the past decade, which reduces the danger by monitoring the on-road environment. In particular, researchers attracted towards the on-road detection of vehicles in recent years. Different parameters have been analyzed in this paper which includes camera placement and the various applications of monocular vehicle detection, common features and common classification methods, motion- based approaches and nighttime vehicle detection and monocular pose estimation. Previous works on the vehicle detection listed based on camera poisons, feature based detection and motion based detection works and night time detection.

  2. Monocular indoor localization techniques for smartphones

    Directory of Open Access Journals (Sweden)

    Hollósi Gergely

    2016-12-01

    Full Text Available In the last decade huge research work has been put to the indoor visual localization of personal smartphones. Considering the available sensor capabilities monocular odometry provides promising solution, even reecting requirements of augmented reality applications. This paper is aimed to give an overview of state-of-the-art results regarding monocular visual localization. For this purpose essential basics of computer vision are presented and the most promising solutions are reviewed.

  3. A Hybrid Architecture for Vision-Based Obstacle Avoidance

    Directory of Open Access Journals (Sweden)

    Mehmet Serdar Güzel

    2013-01-01

    Full Text Available This paper proposes a new obstacle avoidance method using a single monocular vision camera as the only sensor which is called as Hybrid Architecture. This architecture integrates a high performance appearance-based obstacle detection method into an optical flow-based navigation system. The hybrid architecture was designed and implemented to run both methods simultaneously and is able to combine the results of each method using a novel arbitration mechanism. The proposed strategy successfully fused two different vision-based obstacle avoidance methods using this arbitration mechanism in order to permit a safer obstacle avoidance system. Accordingly, to establish the adequacy of the design of the obstacle avoidance system, a series of experiments were conducted. The results demonstrate the characteristics of the proposed architecture, and the results prove that its performance is somewhat better than the conventional optical flow-based architecture. Especially, the robot employing Hybrid Architecture avoids lateral obstacles in a more smooth and robust manner than when using the conventional optical flow-based technique.

  4. Monocular distance estimation with optical flow maneuvers and efference copies: a stability-based strategy.

    Science.gov (United States)

    de Croon, Guido C H E

    2016-01-07

    The visual cue of optical flow plays an important role in the navigation of flying insects, and is increasingly studied for use by small flying robots as well. A major problem is that successful optical flow control seems to require distance estimates, while optical flow is known to provide only the ratio of velocity to distance. In this article, a novel, stability-based strategy is proposed for monocular distance estimation, relying on optical flow maneuvers and knowledge of the control inputs (efference copies). It is shown analytically that given a fixed control gain, the stability of a constant divergence control loop only depends on the distance to the approached surface. At close distances, the control loop starts to exhibit self-induced oscillations. The robot can detect these oscillations and hence be aware of the distance to the surface. The proposed stability-based strategy for estimating distances has two main attractive characteristics. First, self-induced oscillations can be detected robustly by the robot and are hardly influenced by wind. Second, the distance can be estimated during a zero divergence maneuver, i.e., around hover. The stability-based strategy is implemented and tested both in simulation and on board a Parrot AR drone 2.0. It is shown that the strategy can be used to: (1) trigger a final approach response during a constant divergence landing with fixed gain, (2) estimate the distance in hover, and (3) estimate distances during an entire landing if the robot uses adaptive gain control to continuously stay on the 'edge of oscillation.'

  5. Vision-Based People Detection System for Heavy Machine Applications

    Directory of Open Access Journals (Sweden)

    Vincent Fremont

    2016-01-01

    Full Text Available This paper presents a vision-based people detection system for improving safety in heavy machines. We propose a perception system composed of a monocular fisheye camera and a LiDAR. Fisheye cameras have the advantage of a wide field-of-view, but the strong distortions that they create must be handled at the detection stage. Since people detection in fisheye images has not been well studied, we focus on investigating and quantifying the impact that strong radial distortions have on the appearance of people, and we propose approaches for handling this specificity, adapted from state-of-the-art people detection approaches. These adaptive approaches nevertheless have the drawback of high computational cost and complexity. Consequently, we also present a framework for harnessing the LiDAR modality in order to enhance the detection algorithm for different camera positions. A sequential LiDAR-based fusion architecture is used, which addresses directly the problem of reducing false detections and computational cost in an exclusively vision-based system. A heavy machine dataset was built, and different experiments were carried out to evaluate the performance of the system. The results are promising, in terms of both processing speed and performance.

  6. Obstacle Detection and Avoidance System Based on Monocular Camera and Size Expansion Algorithm for UAVs

    Science.gov (United States)

    Al-Kaff, Abdulla; García, Fernando; Martín, David; De La Escalera, Arturo; Armingol, José María

    2017-01-01

    One of the most challenging problems in the domain of autonomous aerial vehicles is the designing of a robust real-time obstacle detection and avoidance system. This problem is complex, especially for the micro and small aerial vehicles, that is due to the Size, Weight and Power (SWaP) constraints. Therefore, using lightweight sensors (i.e., Digital camera) can be the best choice comparing with other sensors; such as laser or radar.For real-time applications, different works are based on stereo cameras in order to obtain a 3D model of the obstacles, or to estimate their depth. Instead, in this paper, a method that mimics the human behavior of detecting the collision state of the approaching obstacles using monocular camera is proposed. The key of the proposed algorithm is to analyze the size changes of the detected feature points, combined with the expansion ratios of the convex hull constructed around the detected feature points from consecutive frames. During the Aerial Vehicle (UAV) motion, the detection algorithm estimates the changes in the size of the area of the approaching obstacles. First, the method detects the feature points of the obstacles, then extracts the obstacles that have the probability of getting close toward the UAV. Secondly, by comparing the area ratio of the obstacle and the position of the UAV, the method decides if the detected obstacle may cause a collision. Finally, by estimating the obstacle 2D position in the image and combining with the tracked waypoints, the UAV performs the avoidance maneuver. The proposed algorithm was evaluated by performing real indoor and outdoor flights, and the obtained results show the accuracy of the proposed algorithm compared with other related works. PMID:28481277

  7. Obstacle Detection and Avoidance System Based on Monocular Camera and Size Expansion Algorithm for UAVs.

    Science.gov (United States)

    Al-Kaff, Abdulla; García, Fernando; Martín, David; De La Escalera, Arturo; Armingol, José María

    2017-05-07

    One of the most challenging problems in the domain of autonomous aerial vehicles is the designing of a robust real-time obstacle detection and avoidance system. This problem is complex, especially for the micro and small aerial vehicles, that is due to the Size, Weight and Power (SWaP) constraints. Therefore, using lightweight sensors (i.e., Digital camera) can be the best choice comparing with other sensors; such as laser or radar.For real-time applications, different works are based on stereo cameras in order to obtain a 3D model of the obstacles, or to estimate their depth. Instead, in this paper, a method that mimics the human behavior of detecting the collision state of the approaching obstacles using monocular camera is proposed. The key of the proposed algorithm is to analyze the size changes of the detected feature points, combined with the expansion ratios of the convex hull constructed around the detected feature points from consecutive frames. During the Aerial Vehicle (UAV) motion, the detection algorithm estimates the changes in the size of the area of the approaching obstacles. First, the method detects the feature points of the obstacles, then extracts the obstacles that have the probability of getting close toward the UAV. Secondly, by comparing the area ratio of the obstacle and the position of the UAV, the method decides if the detected obstacle may cause a collision. Finally, by estimating the obstacle 2D position in the image and combining with the tracked waypoints, the UAV performs the avoidance maneuver. The proposed algorithm was evaluated by performing real indoor and outdoor flights, and the obtained results show the accuracy of the proposed algorithm compared with other related works.

  8. Vision-Based SLAM System for Unmanned Aerial Vehicles.

    Science.gov (United States)

    Munguía, Rodrigo; Urzua, Sarquis; Bolea, Yolanda; Grau, Antoni

    2016-03-15

    The present paper describes a vision-based simultaneous localization and mapping system to be applied to Unmanned Aerial Vehicles (UAVs). The main contribution of this work is to propose a novel estimator relying on an Extended Kalman Filter. The estimator is designed in order to fuse the measurements obtained from: (i) an orientation sensor (AHRS); (ii) a position sensor (GPS); and (iii) a monocular camera. The estimated state consists of the full state of the vehicle: position and orientation and their first derivatives, as well as the location of the landmarks observed by the camera. The position sensor will be used only during the initialization period in order to recover the metric scale of the world. Afterwards, the estimated map of landmarks will be used to perform a fully vision-based navigation when the position sensor is not available. Experimental results obtained with simulations and real data show the benefits of the inclusion of camera measurements into the system. In this sense the estimation of the trajectory of the vehicle is considerably improved, compared with the estimates obtained using only the measurements from the position sensor, which are commonly low-rated and highly noisy.

  9. Vision-Based SLAM System for Unmanned Aerial Vehicles

    Science.gov (United States)

    Munguía, Rodrigo; Urzua, Sarquis; Bolea, Yolanda; Grau, Antoni

    2016-01-01

    The present paper describes a vision-based simultaneous localization and mapping system to be applied to Unmanned Aerial Vehicles (UAVs). The main contribution of this work is to propose a novel estimator relying on an Extended Kalman Filter. The estimator is designed in order to fuse the measurements obtained from: (i) an orientation sensor (AHRS); (ii) a position sensor (GPS); and (iii) a monocular camera. The estimated state consists of the full state of the vehicle: position and orientation and their first derivatives, as well as the location of the landmarks observed by the camera. The position sensor will be used only during the initialization period in order to recover the metric scale of the world. Afterwards, the estimated map of landmarks will be used to perform a fully vision-based navigation when the position sensor is not available. Experimental results obtained with simulations and real data show the benefits of the inclusion of camera measurements into the system. In this sense the estimation of the trajectory of the vehicle is considerably improved, compared with the estimates obtained using only the measurements from the position sensor, which are commonly low-rated and highly noisy. PMID:26999131

  10. Vision-Based SLAM System for Unmanned Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Rodrigo Munguía

    2016-03-01

    Full Text Available The present paper describes a vision-based simultaneous localization and mapping system to be applied to Unmanned Aerial Vehicles (UAVs. The main contribution of this work is to propose a novel estimator relying on an Extended Kalman Filter. The estimator is designed in order to fuse the measurements obtained from: (i an orientation sensor (AHRS; (ii a position sensor (GPS; and (iii a monocular camera. The estimated state consists of the full state of the vehicle: position and orientation and their first derivatives, as well as the location of the landmarks observed by the camera. The position sensor will be used only during the initialization period in order to recover the metric scale of the world. Afterwards, the estimated map of landmarks will be used to perform a fully vision-based navigation when the position sensor is not available. Experimental results obtained with simulations and real data show the benefits of the inclusion of camera measurements into the system. In this sense the estimation of the trajectory of the vehicle is considerably improved, compared with the estimates obtained using only the measurements from the position sensor, which are commonly low-rated and highly noisy.

  11. Sensor Fusion of Monocular Cameras and Laser Rangefinders for Line-Based Simultaneous Localization and Mapping (SLAM Tasks in Autonomous Mobile Robots

    Directory of Open Access Journals (Sweden)

    Xinzheng Zhang

    2012-01-01

    Full Text Available This paper presents a sensor fusion strategy applied for Simultaneous Localization and Mapping (SLAM in dynamic environments. The designed approach consists of two features: (i the first one is a fusion module which synthesizes line segments obtained from laser rangefinder and line features extracted from monocular camera. This policy eliminates any pseudo segments that appear from any momentary pause of dynamic objects in laser data. (ii The second characteristic is a modified multi-sensor point estimation fusion SLAM (MPEF-SLAM that incorporates two individual Extended Kalman Filter (EKF based SLAM algorithms: monocular and laser SLAM. The error of the localization in fused SLAM is reduced compared with those of individual SLAM. Additionally, a new data association technique based on the homography transformation matrix is developed for monocular SLAM. This data association method relaxes the pleonastic computation. The experimental results validate the performance of the proposed sensor fusion and data association method.

  12. Sensor fusion of monocular cameras and laser rangefinders for line-based Simultaneous Localization and Mapping (SLAM) tasks in autonomous mobile robots.

    Science.gov (United States)

    Zhang, Xinzheng; Rad, Ahmad B; Wong, Yiu-Kwong

    2012-01-01

    This paper presents a sensor fusion strategy applied for Simultaneous Localization and Mapping (SLAM) in dynamic environments. The designed approach consists of two features: (i) the first one is a fusion module which synthesizes line segments obtained from laser rangefinder and line features extracted from monocular camera. This policy eliminates any pseudo segments that appear from any momentary pause of dynamic objects in laser data. (ii) The second characteristic is a modified multi-sensor point estimation fusion SLAM (MPEF-SLAM) that incorporates two individual Extended Kalman Filter (EKF) based SLAM algorithms: monocular and laser SLAM. The error of the localization in fused SLAM is reduced compared with those of individual SLAM. Additionally, a new data association technique based on the homography transformation matrix is developed for monocular SLAM. This data association method relaxes the pleonastic computation. The experimental results validate the performance of the proposed sensor fusion and data association method.

  13. A Behaviour-Based Architecture for Mapless Navigation Using Vision

    Directory of Open Access Journals (Sweden)

    Mehmet Serdar Guzel

    2012-04-01

    Full Text Available Autonomous robots operating in an unknown and uncertain environment must be able to cope with dynamic changes to that environment. For a mobile robot in a cluttered environment to navigate successfully to a goal while avoiding obstacles is a challenging problem. This paper presents a new behaviour-based architecture design for mapless navigation. The architecture is composed of several modules and each module generates behaviours. A novel method, inspired from a visual homing strategy, is adapted to a monocular vision-based system to overcome goal-based navigation problems. A neural network-based obstacle avoidance strategy is designed using a 2-D scanning laser. To evaluate the performance of the proposed architecture, the system has been tested using Microsoft Robotics Studio (MRS, which is a very powerful 3D simulation environment. In addition, real experiments to guide a Pioneer 3-DX mobile robot, equipped with a pan-tilt-zoom camera in a cluttered environment are presented. The analysis of the results allows us to validate the proposed behaviour-based navigation strategy.

  14. VEP-based acuity assessment in low vision.

    Science.gov (United States)

    Hoffmann, Michael B; Brands, Jan; Behrens-Baumann, Wolfgang; Bach, Michael

    2017-10-04

    Objective assessment of visual acuity (VA) is possible with VEP methodology, but established with sufficient precision only for vision better than about 1.0 logMAR. We here explore whether this can be extended down to 2.0 logMAR, highly desirable for low-vision evaluations. Based on the stepwise sweep algorithm (Bach et al. in Br J Ophthalmol 92:396-403, 2008) VEPs to monocular steady-state brief onset pattern stimulation (7.5-Hz checkerboards, 40% contrast, 40 ms on, 93 ms off) were recorded for eight different check sizes, from 0.5° to 9.0°, for two runs with three occipital electrodes in a Laplace-approximating montage. We examined 22 visually normal participants where acuity was reduced to ≈ 2.0 logMAR with frosted transparencies. With the established heuristic algorithm the "VEP acuity" was extracted and compared to psychophysical VA, both obtained at 57 cm distance. In 20 of the 22 participants with artificially reduced acuity the automatic analysis indicated a valid result (1.80 logMAR on average) in at least one of the two runs. 95% test-retest limits of agreement on average were ± 0.09 logMAR for psychophysical, and ± 0.21 logMAR for VEP-derived acuity. For 15 participants we obtained results in both runs and averaged them. In 12 of these 15 the low-acuity results stayed within the 95% confidence interval (± 0.3 logMAR) as established by Bach et al. (2008). The fully automated analysis yielded good agreement of psychophysical and electrophysiological VAs in 12 of 15 cases (80%) in the low-vision range down to 2.0 logMAR. This encourages us to further pursue this methodology and assess its value in patients.

  15. Monocular Blindness: Is It a Handicap?

    Science.gov (United States)

    Knoth, Sharon

    1995-01-01

    Students with monocular vision may be in need of special assistance and should be evaluated by a multidisciplinary team to determine whether the visual loss is affecting educational performance. This article discusses the student's eligibility for special services, difficulty in performing depth perception tasks, difficulties in specific classroom…

  16. A trajectory and orientation reconstruction method for moving objects based on a moving monocular camera.

    Science.gov (United States)

    Zhou, Jian; Shang, Yang; Zhang, Xiaohu; Yu, Wenxian

    2015-03-09

    We propose a monocular trajectory intersection method to solve the problem that a monocular moving camera cannot be used for three-dimensional reconstruction of a moving object point. The necessary and sufficient condition of when this method has the unique solution is provided. An extended application of the method is to not only achieve the reconstruction of the 3D trajectory, but also to capture the orientation of the moving object, which would not be obtained by PnP problem methods due to lack of features. It is a breakthrough improvement that develops the intersection measurement from the traditional "point intersection" to "trajectory intersection" in videometrics. The trajectory of the object point can be obtained by using only linear equations without any initial value or iteration; the orientation of the object with poor conditions can also be calculated. The required condition for the existence of definite solution of this method is derived from equivalence relations of the orders of the moving trajectory equations of the object, which specifies the applicable conditions of the method. Simulation and experimental results show that it not only applies to objects moving along a straight line, or a conic and another simple trajectory, but also provides good result for more complicated trajectories, making it widely applicable.

  17. A Probabilistic Feature Map-Based Localization System Using a Monocular Camera

    Directory of Open Access Journals (Sweden)

    Hyungjin Kim

    2015-08-01

    Full Text Available Image-based localization is one of the most widely researched localization techniques in the robotics and computer vision communities. As enormous image data sets are provided through the Internet, many studies on estimating a location with a pre-built image-based 3D map have been conducted. Most research groups use numerous image data sets that contain sufficient features. In contrast, this paper focuses on image-based localization in the case of insufficient images and features. A more accurate localization method is proposed based on a probabilistic map using 3D-to-2D matching correspondences between a map and a query image. The probabilistic feature map is generated in advance by probabilistic modeling of the sensor system as well as the uncertainties of camera poses. Using the conventional PnP algorithm, an initial camera pose is estimated on the probabilistic feature map. The proposed algorithm is optimized from the initial pose by minimizing Mahalanobis distance errors between features from the query image and the map to improve accuracy. To verify that the localization accuracy is improved, the proposed algorithm is compared with the conventional algorithm in a simulation and realenvironments

  18. Monocular visual ranging

    Science.gov (United States)

    Witus, Gary; Hunt, Shawn

    2008-04-01

    The vision system of a mobile robot for checkpoint and perimeter security inspection performs multiple functions: providing surveillance video, providing high resolution still images, and providing video for semi-autonomous visual navigation. Mid-priced commercial digital cameras support the primary inspection functions. Semi-autonomous visual navigation is a tertiary function whose purpose is to reduce the burden of teleoperation and free the security personnel for their primary functions. Approaches to robot visual navigation require some form of depth perception for speed control to prevent the robot from colliding with objects. In this paper present the initial results of an exploration of the capabilities and limitations of using a single monocular commercial digital camera for depth perception. Our approach combines complementary methods in alternating stationary and moving behaviors. When the platform is stationary, it computes a range image from differential blur in the image stack collected at multiple focus settings. When the robot is moving, it extracts an estimate of range from the camera auto-focus function, and combines this with an estimate derived from angular expansion of a constellation of visual tracking points.

  19. Vision based systems for UAV applications

    CERN Document Server

    Kuś, Zygmunt

    2013-01-01

    This monograph is motivated by a significant number of vision based algorithms for Unmanned Aerial Vehicles (UAV) that were developed during research and development projects. Vision information is utilized in various applications like visual surveillance, aim systems, recognition systems, collision-avoidance systems and navigation. This book presents practical applications, examples and recent challenges in these mentioned application fields. The aim of the book is to create a valuable source of information for researchers and constructors of solutions utilizing vision from UAV. Scientists, researchers and graduate students involved in computer vision, image processing, data fusion, control algorithms, mechanics, data mining, navigation and IC can find many valuable, useful and practical suggestions and solutions. The latest challenges for vision based systems are also presented.

  20. Depth scaling in phantom and monocular gap stereograms using absolute distance information.

    Science.gov (United States)

    Kuroki, Daiichiro; Nakamizo, Sachio

    2006-11-01

    The present study aimed to investigate whether the visual system scales apparent depth from binocularly unmatched features by using absolute distance information. In Experiment 1 we examined the effect of convergence on perceived depth in phantom stereograms [Gillam, B., & Nakayama, K. (1999). Quantitative depth for a phantom surface can be based on cyclopean occlusion cues alone. Vision Research, 39, 109-112.], monocular gap stereograms [Pianta, M. J., & Gillam, B. J. (2003a). Monocular gap stereopsis: manipulation of the outer edge disparity and the shape of the gap. Vision Research, 43, 1937-1950.] and random dot stereograms. In Experiments 2 and 3 we examined the effective range of viewing distances for scaling the apparent depths in these stereograms. The results showed that: (a) the magnitudes of perceived depths increased in all stereograms as the estimate of the viewing distance increased while keeping proximal and/or distal sizes of the stimuli constant, and (b) the effective range of viewing distances was significantly shorter in monocular gap stereograms. The first result indicates that the visual system scales apparent depth from unmatched features as well as that from horizontal disparity, while the second suggests that, at far distances, the strength of the depth signal from an unmatched feature in monocular gap stereograms is relatively weaker than that from horizontal disparity.

  1. A novel virtual four-ocular stereo vision system based on single camera for measuring insect motion parameters

    Institute of Scientific and Technical Information of China (English)

    Ying Wang; Guangjun Zhang; Dazhi Chen

    2005-01-01

    A novel virtual four-ocular stereo measurement system based on single high speed camera is proposed for measuring double beating wings of a high speed flapping insect. The principle of virtual monocular system consisting of a few planar mirrors and a single high speed camera is introduced. The stereo vision measurement principle based on optic triangulation is explained. The wing kinematics parameters are measured. Results show that this virtual stereo system not only decreases system cost extremely but also is effective to insect motion measurement.

  2. Automatic Human Facial Expression Recognition Based on Integrated Classifier From Monocular Video with Uncalibrated Camera

    Directory of Open Access Journals (Sweden)

    Yu Tao

    2017-01-01

    Full Text Available An automatic recognition framework for human facial expressions from a monocular video with an uncalibrated camera is proposed. The expression characteristics are first acquired from a kind of deformable template, similar to a facial muscle distribution. After associated regularization, the time sequences from the trait changes in space-time under complete expressional production are then arranged line by line in a matrix. Next, the matrix dimensionality is reduced by a method of manifold learning of neighborhood-preserving embedding. Finally, the refined matrix containing the expression trait information is recognized by a classifier that integrates the hidden conditional random field (HCRF and support vector machine (SVM. In an experiment using the Cohn–Kanade database, the proposed method showed a comparatively higher recognition rate than the individual HCRF or SVM methods in direct recognition from two-dimensional human face traits. Moreover, the proposed method was shown to be more robust than the typical Kotsia method because the former contains more structural characteristics of the data to be classified in space-time

  3. Cross-Covariance Estimation for Ekf-Based Inertial Aided Monocular Slam

    Science.gov (United States)

    Kleinert, M.; Stilla, U.

    2011-04-01

    Repeated observation of several characteristically textured surface elements allows the reconstruction of the camera trajectory and a sparse point cloud which is often referred to as "map". The extended Kalman filter (EKF) is a popular method to address this problem, especially if real-time constraints have to be met. Inertial measurements as well as a parameterization of the state vector that conforms better to the linearity assumptions made by the EKF may be employed to reduce the impact of linearization errors. Therefore, we adopt an inertial-aided monocular SLAM approach where landmarks are parameterized in inverse depth w.r.t. the coordinate system in which they were observed for the first time. In this work we present a method to estimate the cross-covariances between landmarks which are introduced in the EKF state vector for the first time and the old filter state that can be applied in the special case at hand where each landmark is parameterized w.r.t. an individual coordinate system.

  4. Gain-scheduling control of a monocular vision-based human-following robot

    CSIR Research Space (South Africa)

    Burke, Michael G

    2011-08-01

    Full Text Available -to-point controller, which is less prone to losing a faster moving target, is preferred. The platform?s angular velocity input is then generated by the weighted sum ?(k) = ( |?(k)| ?max ) ?1(k) + ( 1? |?(k)| ?max ) ?2(k), (7) with ?max the maximum... be further refined through the use of a Kalman filter. We select the measurement uncertainty as one third of the typical pose variation in straight line motion, weighted by a factor w = 1 ? ni/nt. Here ni indicates the number of inliers returned...

  5. Monocular 3D display unit using soft actuator for parallax image shift

    Science.gov (United States)

    Sakamoto, Kunio; Kodama, Yuuki

    2010-11-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth. This vision unit needs an image shift optics for generating monocular parallax images. But conventional image shift mechanism is heavy because of its linear actuator system. To improve this problem, we developed a light-weight 3D vision unit for presenting monocular stereoscopic images using a soft linear actuator made of a polypyrrole film.

  6. Light-weight monocular display unit for 3D display using polypyrrole film actuator

    Science.gov (United States)

    Sakamoto, Kunio; Ohmori, Koji

    2010-10-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth. This vision unit needs an image shift optics for generating monocular parallax images. But conventional image shift mechanism is heavy because of its linear actuator system. To improve this problem, we developed a light-weight 3D vision unit for presenting monocular stereoscopic images using a polypyrrole linear actuator.

  7. Validation of Data Association for Monocular SLAM

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2013-01-01

    Full Text Available Simultaneous Mapping and Localization (SLAM is a multidisciplinary problem with ramifications within several fields. One of the key aspects for its popularity and success is the data fusion produced by SLAM techniques, providing strong and robust sensory systems even with simple devices, such as webcams in Monocular SLAM. This work studies a novel batch validation algorithm, the highest order hypothesis compatibility test (HOHCT, against one of the most popular approaches, the JCCB. The HOHCT approach has been developed as a way to improve performance of the delayed inverse-depth initialization monocular SLAM, a previously developed monocular SLAM algorithm based on parallax estimation. Both HOHCT and JCCB are extensively tested and compared within a delayed inverse-depth initialization monocular SLAM framework, showing the strengths and costs of this proposal.

  8. Monocular 3D display system for presenting correct depth

    Science.gov (United States)

    Sakamoto, Kunio; Hosomi, Takashi

    2009-10-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth.

  9. Pattern adaptation of relay cells in the lateral geniculate nucleus of binocular and monocular vision-deprived cats%双眼和单眼视觉剥夺猫外膝体细胞的图形适应

    Institute of Scientific and Technical Information of China (English)

    王伟; 寿天德

    2000-01-01

    为测定丘脑外膝体细胞的图形适应是否依赖于早期视觉经验, 在细胞外记录了双眼和单眼缝合的猫外膝体中继细胞对长时间运动光栅刺激的反应. 在双眼剥夺猫,占68%的记录到的细胞在30 s内反应下降到稳定值,其平均反应值下降33%,适应程度较正常猫显著.在单眼剥夺猫,记录到的剥夺眼驱动的和非剥夺眼驱动的细胞中,分别有占53%和44%的细胞显示图形适应, 两者差别不大.研究表明, 早期视剥夺能增强或保持图形适应, 提示图形适应是外膝体细胞常见的固有性质,可能主要由遗传因素所决定.%To test whether the pattern adaptation in thalamus is dependent upon postnatal visual experience during early life, the responses of relay cells to prolonged drifting grating stimulation were recorded extracellularly from the dorsal lateral geniculate nucleus (dLGN) of cats reared with binocular and monocular lid suture. In binocular vision-deprived cats, 68% of cells recorded showed significant adaptation to prolonged grating stimuli within 30 s, with a mean response decrease of 33%, and then stabilized gradually. This adaptation was stronger than that of relay cells in normal cats. In monocular vision-deprived cats, 53% of the cells driven by the deprived eye showed similar adaptation as did 44% of the cells driven by the non-deprived eye. These results indicate that pattern adaptation could be maintained or even enhanced after visual deprivation in early life. It is suggested that pattern adaptation is a general and intrinsic property of the dLGN cells, which may be mainly determined by genetic factors.

  10. A 3D Human Skeletonization Algorithm for a Single Monocular Camera Based on Spatial–Temporal Discrete Shadow Integration

    Directory of Open Access Journals (Sweden)

    Jie Hou

    2017-07-01

    Full Text Available Three-dimensional (3D human skeleton extraction is a powerful tool for activity acquirement and analyses, spawning a variety of applications on somatosensory control, virtual reality and many prospering fields. However, the 3D human skeletonization relies heavily on RGB-Depth (RGB-D cameras, expensive wearable sensors and specific lightening conditions, resulting in great limitation of its outdoor applications. This paper presents a novel 3D human skeleton extraction method designed for the monocular camera large scale outdoor scenarios. The proposed algorithm aggregates spatial–temporal discrete joint positions extracted from human shadow on the ground. Firstly, the projected silhouette information is recovered from human shadow on the ground for each frame, followed by the extraction of two-dimensional (2D joint projected positions. Then extracted 2D joint positions are categorized into different sets according to activity silhouette categories. Finally, spatial–temporal integration of same-category 2D joint positions is carried out to generate 3D human skeletons. The proposed method proves accurate and efficient in outdoor human skeletonization application based on several comparisons with the traditional RGB-D method. Finally, the application of the proposed method to RGB-D skeletonization enhancement is discussed.

  11. Bringing Vision-Based Measurements into our Daily Life: A Grand Challenge for Computer Vision Systems

    OpenAIRE

    Scharcanski, Jacob

    2016-01-01

    Bringing computer vision into our daily life has been challenging researchers in industry and in academia over the past decades. However, the continuous development of cameras and computing systems turned computer vision-based measurements into a viable option, allowing new solutions to known problems. In this context, computer vision is a generic tool that can be used to measure and monitor phenomena in wide range of fields. The idea of using vision-based measurements is appealing, since the...

  12. Large-scale monocular FastSLAM2.0 acceleration on an embedded heterogeneous architecture

    Science.gov (United States)

    Abouzahir, Mohamed; Elouardi, Abdelhafid; Bouaziz, Samir; Latif, Rachid; Tajer, Abdelouahed

    2016-12-01

    Simultaneous localization and mapping (SLAM) is widely used in many robotic applications and autonomous navigation. This paper presents a study of FastSLAM2.0 computational complexity based on a monocular vision system. The algorithm is intended to operate with many particles in a large-scale environment. FastSLAM2.0 was partitioned into functional blocks allowing a hardware software matching on a CPU-GPGPU-based SoC architecture. Performances in terms of processing time and localization accuracy were evaluated using a real indoor dataset. Results demonstrate that an optimized and efficient CPU-GPGPU partitioning allows performing accurate localization results and high-speed execution of a monocular FastSLAM2.0-based embedded system operating under real-time constraints.

  13. Human Pose Estimation from Monocular Images: A Comprehensive Survey

    Directory of Open Access Journals (Sweden)

    Wenjuan Gong

    2016-11-01

    Full Text Available Human pose estimation refers to the estimation of the location of body parts and how they are connected in an image. Human pose estimation from monocular images has wide applications (e.g., image indexing. Several surveys on human pose estimation can be found in the literature, but they focus on a certain category; for example, model-based approaches or human motion analysis, etc. As far as we know, an overall review of this problem domain has yet to be provided. Furthermore, recent advancements based on deep learning have brought novel algorithms for this problem. In this paper, a comprehensive survey of human pose estimation from monocular images is carried out including milestone works and recent advancements. Based on one standard pipeline for the solution of computer vision problems, this survey splits the problem into several modules: feature extraction and description, human body models, and modeling methods. Problem modeling methods are approached based on two means of categorization in this survey. One way to categorize includes top-down and bottom-up methods, and another way includes generative and discriminative methods. Considering the fact that one direct application of human pose estimation is to provide initialization for automatic video surveillance, there are additional sections for motion-related methods in all modules: motion features, motion models, and motion-based methods. Finally, the paper also collects 26 publicly available data sets for validation and provides error measurement methods that are frequently used.

  14. 3D Perception of Biomimetic Eye Based on Motion Vision and Stereo Vision%仿生眼运动视觉与立体视觉3维感知

    Institute of Scientific and Technical Information of China (English)

    王庆滨; 邹伟; 徐德; 张峰

    2015-01-01

    In order to overcome the narrow visual field of binocular vision and the low precision of monocular vision, a binocular biomimetic eye platform with 4 rotational degrees of freedom is designed based on the structural characteristics of human eyes, so that the robot can achieve human-like environment perception with binocular stereo vision and monoc-ular motion vision. Initial location and parameters calibration of the biomimetic eye platform are accomplished based on the vision alignment strategy and hand-eye calibration. The methods of binocular stereo perception and monocular motion stereo perception are given based on the dynamically changing external parameters. The former perceives the 3D information through the two images obtained by two cameras in real-time and their relative posture, and the latter perceives the 3D infor-mation by synthesize multiple images obtained by one camera and its corresponding postures at multiple adjacent moments. Experimental results shows that the relative perception accuracy of binocular vision is 0.38% and the relative perception accuracy of monocular motion vision is 0.82%. In conclusion, the method proposed can broaden the field of binocular vision, and ensure the accuracy of binocular perception and monocular motion perception.%为使机器人同时具备双目立体视觉和单目运动视觉的仿人化环境感知能力,克服双目视场狭窄、单目深度感知精度低的缺陷,本文基于人眼结构特点,设计了一个具有4个旋转自由度的双目仿生眼平台,并分别基于视觉对准策略和手眼标定技术实现了该平台的初始定位和参数标定.给出了基于外部参数动态变化的双目立体感知方法和单目运动立体感知方法,前者通过两架摄像机实时获取的图像信息以及摄像机相对位姿信息进行3维感知,后者综合利用单个摄像机在多个相邻时刻获取的多个图像及其对应姿态进行3维感知.实验结果中的双目

  15. Research on Solution Geometric Space for Monocular Vision Measurement Method%单目视觉测量方法的求解几何空间研究

    Institute of Scientific and Technical Information of China (English)

    秦丽娟

    2013-01-01

    A new method of solution is proposed for vision measurement method with spatial straight lines intersecting at two points. This method has advantage of fast calculation and can guarantee the uniqueness of solution. The precondition of application of this method is to satisfy monotony. The geometric space is found to satisfy monotony, which ensures vision measurement method to converge to the correct solution and gives the detailed proof. Research on solving geometric space can provide a theoretical basis for application of iterative method and guide vision measurement algorithm.%针对交于两点空间直线视觉测量方法提出一种新的求解方法,这种求解方法计算速度快同时能够保证解的唯一性.应用该求解方法的前提条件是满足单调性,找到能够使得求解方法满足单调性的几何空间,从而保证视觉测量方法收敛到正确解.研究了能够使得求解方法满足单调性的几何空间并给出了详细的证明过程.求解几何空间的研究能够为迭代求解方法的应用提供理论基础,指导视觉测量算法的应用.

  16. Stereo vision based SLAM using Rao-Blackwellised particle filter

    Institute of Scientific and Technical Information of China (English)

    Er-yong WU; Gong-yan LI; Zhi-yu XIANG; Ji-lin LIU

    2008-01-01

    We present an algorithm which can realize 3D stereo vision simultaneous localization and mapping (SLAM) for mobile robot in unknown outdoor environments, which means the 6-DOF motion and a sparse but persistent map of natural landmarks be constructed online only with a stereo camera. In mobile robotics research, we extend FastSLAM 2.0 like stereo vision SLAM with "pure vision" domain to outdoor environments. Unlike popular stochastic motion model used in conventional monocular vision SLAM, we utilize the ideas of structure from motion (SFM) for initial motion estimation, which is more suitable for the robot moving in large-scale outdoor, and textured environments. SIFT features are used as natural landmarks, and its 3D positions are constructed directly through triangulation. Considering the computational complexity and memory consumption,Bkd-tree and Best-Bin-First (BBF) search strategy are utilized for SIFT feature descriptor matching. Results show high accuracy of our algorithm, even in the circumstance of large translation and large rotation movements.

  17. Monocular transparency generates quantitative depth.

    Science.gov (United States)

    Howard, Ian P; Duke, Philip A

    2003-11-01

    Monocular zones adjacent to depth steps can create an impression of depth in the absence of binocular disparity. However, the magnitude of depth is not specified. We designed a stereogram that provides information about depth magnitude but which has no disparity. The effect depends on transparency rather than occlusion. For most subjects, depth magnitude produced by monocular transparency was similar to that created by a disparity-defined depth probe. Addition of disparity to monocular transparency did not improve the accuracy of depth settings. The magnitude of depth created by monocular occlusion fell short of that created by monocular transparency.

  18. Vision based behaviors for a legged robot

    OpenAIRE

    Ruiz, Juan V.; Montero, Pablo; Martín Rico, Francisco; Matellán Olivera, Vicente

    2005-01-01

    This article describes two vision-based behaviors designed for an autonomous legged robot. These behaviors have been designed in a modular way in order to be able to integrate them in an architecture named DSH (Dynamic Schema Hierarchies), which is also briefly described. These behaviors have been tested in office indoor environments and experiments carried out are also described in this paper. The platform used in these experiments carried out are also described in theis paper. The platform ...

  19. Fiducial-based monocular 3D displacement measurement of breakwater armour unit models.

    CSIR Research Space (South Africa)

    Vieira, R

    2008-11-01

    Full Text Available This paper presents a fiducial-based approach to monitoring the movement of breakwater armour units in a model hall environment. Target symbols with known dimensions are attached to the physical models, allowing the recovery of three...

  20. The role of monocularly visible regions in depth and surface perception.

    Science.gov (United States)

    Harris, Julie M; Wilcox, Laurie M

    2009-11-01

    The mainstream of binocular vision research has long been focused on understanding how binocular disparity is used for depth perception. In recent years, researchers have begun to explore how monocular regions in binocularly viewed scenes contribute to our perception of the three-dimensional world. Here we review the field as it currently stands, with a focus on understanding the extent to which the role of monocular regions in depth perception can be understood using extant theories of binocular vision.

  1. A New Feature Points Reconstruction Method in Spacecraft Vision Navigation

    Directory of Open Access Journals (Sweden)

    Bing Hua

    2015-01-01

    Full Text Available The important applications of monocular vision navigation in aerospace are spacecraft ground calibration tests and spacecraft relative navigation. Regardless of the attitude calibration for ground turntable or the relative navigation between two spacecraft, it usually requires four noncollinear feature points to achieve attitude estimation. In this paper, a vision navigation system based on the least feature points is designed to deal with fault or unidentifiable feature points. An iterative algorithm based on the feature point reconstruction is proposed for the system. Simulation results show that the attitude calculation of the designed vision navigation system could converge quickly, which improves the robustness of the vision navigation of spacecraft.

  2. Monocular SLAM for Visual Odometry: A Full Approach to the Delayed Inverse-Depth Feature Initialization Method

    Directory of Open Access Journals (Sweden)

    Rodrigo Munguía

    2012-01-01

    Full Text Available This paper describes in a detailed manner a method to implement a simultaneous localization and mapping (SLAM system based on monocular vision for applications of visual odometry, appearance-based sensing, and emulation of range-bearing measurements. SLAM techniques are required to operate mobile robots in a priori unknown environments using only on-board sensors to simultaneously build a map of their surroundings; this map will be needed for the robot to track its position. In this context, the 6-DOF (degree of freedom monocular camera case (monocular SLAM possibly represents the harder variant of SLAM. In monocular SLAM, a single camera, which is freely moving through its environment, represents the sole sensory input to the system. The method proposed in this paper is based on a technique called delayed inverse-depth feature initialization, which is intended to initialize new visual features on the system. In this work, detailed formulation, extended discussions, and experiments with real data are presented in order to validate and to show the performance of the proposal.

  3. Inexpensive Monocular Pico-Projector-based Augmented Reality Display for Surgical Microscope.

    Science.gov (United States)

    Shi, Chen; Becker, Brian C; Riviere, Cameron N

    2012-01-01

    This paper describes an inexpensive pico-projector-based augmented reality (AR) display for a surgical microscope. The system is designed for use with Micron, an active handheld surgical tool that cancels hand tremor of surgeons to improve microsurgical accuracy. Using the AR display, virtual cues can be injected into the microscope view to track the movement of the tip of Micron, show the desired position, and indicate the position error. Cues can be used to maintain high performance by helping the surgeon to avoid drifting out of the workspace of the instrument. Also, boundary information such as the view range of the cameras that record surgical procedures can be displayed to tell surgeons the operation area. Furthermore, numerical, textual, or graphical information can be displayed, showing such things as tool tip depth in the work space and on/off status of the canceling function of Micron.

  4. Vision based flight procedure stereo display system

    Science.gov (United States)

    Shen, Xiaoyun; Wan, Di; Ma, Lan; He, Yuncheng

    2008-03-01

    A virtual reality flight procedure vision system is introduced in this paper. The digital flight map database is established based on the Geographic Information System (GIS) and high definitions satellite remote sensing photos. The flight approaching area database is established through computer 3D modeling system and GIS. The area texture is generated from the remote sensing photos and aerial photographs in various level of detail. According to the flight approaching procedure, the flight navigation information is linked to the database. The flight approaching area vision can be dynamic displayed according to the designed flight procedure. The flight approaching area images are rendered in 2 channels, one for left eye images and the others for right eye images. Through the polarized stereoscopic projection system, the pilots and aircrew can get the vivid 3D vision of the flight destination approaching area. Take the use of this system in pilots preflight preparation procedure, the aircrew can get more vivid information along the flight destination approaching area. This system can improve the aviator's self-confidence before he carries out the flight mission, accordingly, the flight safety is improved. This system is also useful in validate the visual flight procedure design, and it helps to the flight procedure design.

  5. Method for SLAM Based on Omnidirectional Vision: A Delayed-EKF Approach

    Directory of Open Access Journals (Sweden)

    Rodrigo Munguía

    2017-01-01

    Full Text Available This work presents a method for implementing a visual-based simultaneous localization and mapping (SLAM system using omnidirectional vision data, with application to autonomous mobile robots. In SLAM, a mobile robot operates in an unknown environment using only on-board sensors to simultaneously build a map of its surroundings, which it uses to track its position. The SLAM is perhaps one of the most fundamental problems to solve in robotics to build mobile robots truly autonomous. The visual sensor used in this work is an omnidirectional vision sensor; this sensor provides a wide field of view which is advantageous in a mobile robot in an autonomous navigation task. Since the visual sensor used in this work is monocular, a method to recover the depth of the features is required. To estimate the unknown depth we propose a novel stochastic triangulation technique. The system proposed in this work can be applied to indoor or cluttered environments for performing visual-based navigation when GPS signal is not available. Experiments with synthetic and real data are presented in order to validate the proposal.

  6. Monocular Road Detection Using Structured Random Forest

    Directory of Open Access Journals (Sweden)

    Liang Xiao

    2016-05-01

    Full Text Available Road detection is a key task for autonomous land vehicles. Monocular vision-based road detection algorithms are mostly based on machine learning approaches and are usually cast as classification problems. However, the pixel-wise classifiers are faced with the ambiguity caused by changes in road appearance, illumination and weather. An effective way to reduce the ambiguity is to model the contextual information with structured learning and prediction. Currently, the widely used structured prediction model in road detection is the Markov random field or conditional random field. However, the random field-based methods require additional complex optimization after pixel-wise classification, making them unsuitable for real-time applications. In this paper, we present a structured random forest-based road-detection algorithm which is capable of modelling the contextual information efficiently. By mapping the structured label space to a discrete label space, the test function of each split node can be trained in a similar way to that of the classical random forests. Structured random forests make use of the contextual information of image patches as well as the structural information of the labels to get more consistent results. Besides this benefit, by predicting a batch of pixels in a single classification, the structured random forest-based road detection can be much more efficient than the conventional pixel-wise random forest. Experimental results tested on the KITTI-ROAD dataset and data collected in typical unstructured environments show that structured random forest-based road detection outperforms the classical pixel-wise random forest both in accuracy and efficiency.

  7. Vision-Based System of AUV for An Underwater Pipeline Tracker

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tie-dong; ZENG Wen-jing; WAN Lei; QIN Zai-bai

    2012-01-01

    This paper describes a new framework for detection and tracking of underwater pipeline,which includes software system and hardware system.It is designed for vision system of AUV based on monocular CCD camera.First,the real-time data flow from image capture card is pre-processed and pipeline features are extracted for navigation.The region saturation degree is advanced to remove false edge point group after Sobel operation.An appropriate way is proposed to clear the disturbance around the peak point in the process of Hough transform.Second,the continuity of pipeline layout is taken into account to improve the efficiency of line extraction.Once the line information has been obtained,the reference zone is predicted by Kalman filter.It denotes the possible appearance position of the pipeline in the image.Kalman filter is used to estimate this position in next frame so that the information of pipeline of each frame can be known in advance.Results obtained on real optic vision data in tank experiment are displayed and discussed.They show that the proposed system can detect and track the underwater pipeline online,and is effective and feasible.

  8. Vision-Based Steering Control, Speed Assistance and Localization for Inner-City Vehicles.

    Science.gov (United States)

    Olivares-Mendez, Miguel Angel; Sanchez-Lopez, Jose Luis; Jimenez, Felipe; Campoy, Pascual; Sajadi-Alamdari, Seyed Amin; Voos, Holger

    2016-03-11

    Autonomous route following with road vehicles has gained popularity in the last few decades. In order to provide highly automated driver assistance systems, different types and combinations of sensors have been presented in the literature. However, most of these approaches apply quite sophisticated and expensive sensors, and hence, the development of a cost-efficient solution still remains a challenging problem. This work proposes the use of a single monocular camera sensor for an automatic steering control, speed assistance for the driver and localization of the vehicle on a road. Herein, we assume that the vehicle is mainly traveling along a predefined path, such as in public transport. A computer vision approach is presented to detect a line painted on the road, which defines the path to follow. Visual markers with a special design painted on the road provide information to localize the vehicle and to assist in its speed control. Furthermore, a vision-based control system, which keeps the vehicle on the predefined path under inner-city speed constraints, is also presented. Real driving tests with a commercial car on a closed circuit finally prove the applicability of the derived approach. In these tests, the car reached a maximum speed of 48 km/h and successfully traveled a distance of 7 km without the intervention of a human driver and any interruption.

  9. Vision-Based Steering Control, Speed Assistance and Localization for Inner-City Vehicles

    Directory of Open Access Journals (Sweden)

    Miguel Angel Olivares-Mendez

    2016-03-01

    Full Text Available Autonomous route following with road vehicles has gained popularity in the last few decades. In order to provide highly automated driver assistance systems, different types and combinations of sensors have been presented in the literature. However, most of these approaches apply quite sophisticated and expensive sensors, and hence, the development of a cost-efficient solution still remains a challenging problem. This work proposes the use of a single monocular camera sensor for an automatic steering control, speed assistance for the driver and localization of the vehicle on a road. Herein, we assume that the vehicle is mainly traveling along a predefined path, such as in public transport. A computer vision approach is presented to detect a line painted on the road, which defines the path to follow. Visual markers with a special design painted on the road provide information to localize the vehicle and to assist in its speed control. Furthermore, a vision-based control system, which keeps the vehicle on the predefined path under inner-city speed constraints, is also presented. Real driving tests with a commercial car on a closed circuit finally prove the applicability of the derived approach. In these tests, the car reached a maximum speed of 48 km/h and successfully traveled a distance of 7 km without the intervention of a human driver and any interruption.

  10. Vision-Based Steering Control, Speed Assistance and Localization for Inner-City Vehicles

    Science.gov (United States)

    Olivares-Mendez, Miguel Angel; Sanchez-Lopez, Jose Luis; Jimenez, Felipe; Campoy, Pascual; Sajadi-Alamdari, Seyed Amin; Voos, Holger

    2016-01-01

    Autonomous route following with road vehicles has gained popularity in the last few decades. In order to provide highly automated driver assistance systems, different types and combinations of sensors have been presented in the literature. However, most of these approaches apply quite sophisticated and expensive sensors, and hence, the development of a cost-efficient solution still remains a challenging problem. This work proposes the use of a single monocular camera sensor for an automatic steering control, speed assistance for the driver and localization of the vehicle on a road. Herein, we assume that the vehicle is mainly traveling along a predefined path, such as in public transport. A computer vision approach is presented to detect a line painted on the road, which defines the path to follow. Visual markers with a special design painted on the road provide information to localize the vehicle and to assist in its speed control. Furthermore, a vision-based control system, which keeps the vehicle on the predefined path under inner-city speed constraints, is also presented. Real driving tests with a commercial car on a closed circuit finally prove the applicability of the derived approach. In these tests, the car reached a maximum speed of 48 km/h and successfully traveled a distance of 7 km without the intervention of a human driver and any interruption. PMID:26978365

  11. Vision-based measurement of microassembly forces

    Science.gov (United States)

    Anis, Y. H.; Mills, J. K.; Cleghorn, W. L.

    2006-08-01

    This work describes a vision-based force sensing method for measuring microforces acting upon the jaws of passive, compliant microgrippers, used to construct 3D microstructures. The importance of jaw force measurement during microassembly is to confirm that the microgripper-micropart makes a successful grasp and to protect the microparts and microgripper from excessive forces which may lead to damage during the assembly process. Finite-element analysis of the microgripper is performed to determine the relation between the displacement and the resultant forces of its jaw. The resulting nearly linear force-displacement relationship is fitted to a first-degree equation. A mathematical model of the microgripper system validated this force-displacement relation. The proposed vision-based gripper force measurement techniques determine the deflections of the microgripper jaws during the microassembly process. The deflections in the gripper jaws are measured during the microassembly processes through computation of the relative displacements of the right and left microgripper jaws with respect to the microgripper base. Two approaches are proposed. The first approach uses pattern identification to measure these relative displacements. Two-dimensional pattern identification is performed using normalized cross-correlation to estimate the degree to which the image and pattern are correlated. The second approach uses object recognition and image processing methods, such as zero-crossing Laplacian of Gaussian edge detection and region filling. Experiments performed confirm the success of both approaches in measuring the microgripper jaw deflections and therefore the assembly forces.

  12. Disparity biasing in depth from monocular occlusions.

    Science.gov (United States)

    Tsirlin, Inna; Wilcox, Laurie M; Allison, Robert S

    2011-07-15

    Monocular occlusions have been shown to play an important role in stereopsis. Among other contributions to binocular depth perception, monocular occlusions can create percepts of illusory occluding surfaces. It has been argued that the precise location in depth of these illusory occluders is based on the constraints imposed by occlusion geometry. Tsirlin et al. (2010) proposed that when these constraints are weak, the depth of the illusory occluder can be biased by a neighboring disparity-defined feature. In the present work we test this hypothesis using a variety of stimuli. We show that when monocular occlusions provide only partial constraints on the magnitude of depth of the illusory occluders, the perceived depth of the occluders can be biased by disparity-defined features in the direction unrestricted by the occlusion geometry. Using this disparity bias phenomenon we also show that in illusory occluder stimuli where disparity information is present, but weak, most observers rely on disparity while some use occlusion information instead to specify the depth of the illusory occluder. Taken together our experiments demonstrate that in binocular depth perception disparity and monocular occlusion cues interact in complex ways to resolve perceptual ambiguity. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Monocular blur alters the tuning characteristics of stereopsis for spatial frequency and size.

    Science.gov (United States)

    Li, Roger W; So, Kayee; Wu, Thomas H; Craven, Ashley P; Tran, Truyet T; Gustafson, Kevin M; Levi, Dennis M

    2016-09-01

    Our sense of depth perception is mediated by spatial filters at different scales in the visual brain; low spatial frequency channels provide the basis for coarse stereopsis, whereas high spatial frequency channels provide for fine stereopsis. It is well established that monocular blurring of vision results in decreased stereoacuity. However, previous studies have used tests that are broadband in their spatial frequency content. It is not yet entirely clear how the processing of stereopsis in different spatial frequency channels is altered in response to binocular input imbalance. Here, we applied a new stereoacuity test based on narrow-band Gabor stimuli. By manipulating the carrier spatial frequency, we were able to reveal the spatial frequency tuning of stereopsis, spanning from coarse to fine, under blurred conditions. Our findings show that increasing monocular blur elevates stereoacuity thresholds 'selectively' at high spatial frequencies, gradually shifting the optimum frequency to lower spatial frequencies. Surprisingly, stereopsis for low frequency targets was only mildly affected even with an acuity difference of eight lines on a standard letter chart. Furthermore, we examined the effect of monocular blur on the size tuning function of stereopsis. The clinical implications of these findings are discussed.

  14. Bayesian depth estimation from monocular natural images.

    Science.gov (United States)

    Su, Che-Chun; Cormack, Lawrence K; Bovik, Alan C

    2017-05-01

    Estimating an accurate and naturalistic dense depth map from a single monocular photographic image is a difficult problem. Nevertheless, human observers have little difficulty understanding the depth structure implied by photographs. Two-dimensional (2D) images of the real-world environment contain significant statistical information regarding the three-dimensional (3D) structure of the world that the vision system likely exploits to compute perceived depth, monocularly as well as binocularly. Toward understanding how this might be accomplished, we propose a Bayesian model of monocular depth computation that recovers detailed 3D scene structures by extracting reliable, robust, depth-sensitive statistical features from single natural images. These features are derived using well-accepted univariate natural scene statistics (NSS) models and recent bivariate/correlation NSS models that describe the relationships between 2D photographic images and their associated depth maps. This is accomplished by building a dictionary of canonical local depth patterns from which NSS features are extracted as prior information. The dictionary is used to create a multivariate Gaussian mixture (MGM) likelihood model that associates local image features with depth patterns. A simple Bayesian predictor is then used to form spatial depth estimates. The depth results produced by the model, despite its simplicity, correlate well with ground-truth depths measured by a current-generation terrestrial light detection and ranging (LIDAR) scanner. Such a strong form of statistical depth information could be used by the visual system when creating overall estimated depth maps incorporating stereopsis, accommodation, and other conditions. Indeed, even in isolation, the Bayesian predictor delivers depth estimates that are competitive with state-of-the-art "computer vision" methods that utilize highly engineered image features and sophisticated machine learning algorithms.

  15. Optical stimulator for vision-based sensors

    DEFF Research Database (Denmark)

    Rössler, Dirk; Pedersen, David Arge Klevang; Benn, Mathias

    2014-01-01

    We have developed an optical stimulator system for vision-based sensors. The stimulator is an efficient tool for stimulating a camera during on-ground testing with scenes representative of spacecraft flights. Such scenes include starry sky, planetary objects, and other spacecraft. The optical...... precision and long-term stability. The system can be continuously used over several days. By facilitating a full camera including optics in the loop, the stimulator enables the more realistic simulation of flight maneuvers based on navigation cameras than pure computer simulations or camera stimulations...... stimulator is used as a test bench to simulate high-precision navigation by different types of camera systems that are used onboard spacecraft, planetary rovers, and for spacecraft rendezvous and proximity maneuvers. Careful hardware design and preoperational calibration of the stimulator result in high...

  16. Machine-vision based optofluidic cell sorting

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Bañas, Andrew

    In contemporary life science there is an increasing emphasis on sorting rare disease-indicating cells within small dilute quantities such as in the confines of optofluidic lab-on-chip devices. Our approach to this is based on the use of optical forces to isolate red blood cells detected by advanc...... the available light and creating 2D or 3D beam distributions aimed at the positions of the detected cells. Furthermore, the beam shaping freedom provided by GPC can allow optimizations in the beam’s propagation and its interaction with the laser catapulted and sorted cells....... machine vision1. This approach is gentler, less invasive and more economical compared to conventional FACS-systems. As cells are less responsive to plastic or glass objects commonly used in the optical manipulation literature2, and since laser safety would be an issue in clinical use, we develop efficient...

  17. Vision based condition assessment of structures

    Energy Technology Data Exchange (ETDEWEB)

    Uhl, Tadeusz; Kohut, Piotr; Holak, Krzysztof; Krupinski, Krzysztof, E-mail: tuhl@agh.edu.pl, E-mail: pko@agh.edu.pl, E-mail: holak@agh.edu.pl, E-mail: krzysiek.krupinski@wp.pl [Department of Robotics and Mechatronics, AGH-University of Science and Technology, Al.Mickiewicza 30, 30-059 Cracow (Poland)

    2011-07-19

    In this paper, a vision-based method for measuring a civil engineering construction's in-plane deflection curves is presented. The displacement field of the analyzed object which results from loads was computed by means of a digital image correlation coefficient. Image registration techniques were introduced to increase the flexibility of the method. The application of homography mapping enabled the deflection field to be computed from two images of the structure, acquired from two different points in space. An automatic shape filter and a corner detector were implemented to calculate the homography mapping between the two views. The developed methodology, created architecture and the capabilities of software tools, as well as experimental results obtained from tests made on a lab set-up and civil engineering constructions, are discussed.

  18. Model-based vision for car following

    Science.gov (United States)

    Schneiderman, Henry; Nashman, Marilyn; Lumia, Ronald

    1993-08-01

    This paper describes a vision processing algorithm that supports autonomous car following. The algorithm visually tracks the position of a `lead vehicle' from the vantage of a pursuing `chase vehicle.' The algorithm requires a 2-D model of the back of the lead vehicle. This model is composed of line segments corresponding to features that give rise to strong edges. There are seven sequential stages of computation: (1) Extracting edge points; (2) Associating extracted edge points with the model features; (3) Determining the position of each model feature; (4) Determining the model position; (5) Updating the motion model of the object; (6) Predicting the position of the object in next image; (7) Predicting the location of all object features from prediction of object position. All processing is confined to the 2-D image plane. The 2-D model location computed in this processing is used to determine the position of the lead vehicle with respect to a 3-D coordinate frame affixed to the chase vehicle. This algorithm has been used as part of a complete system to drive an autonomous vehicle, a High Mobility Multipurpose Wheeled Vehicle (HMMWV) such that it follows a lead vehicle at speeds up to 35 km/hr. The algorithm runs at an update rate of 15 Hertz and has a worst case computational delay of 128 ms. The algorithm is implemented under the NASA/NBS Standard Reference Model for Telerobotic Control System Architecture (NASREM) and runs on a dedicated vision processing engine and a VME-based multiprocessor system.

  19. Vision-based control of the Manus using SIFT

    NARCIS (Netherlands)

    Liefhebber, F.; Sijs, J.

    2007-01-01

    The rehabilitation robot Manus is an assistive device for severely motor handicapped users. The executing of all day living tasks with the Manus, can be very complex and a vision-based controller can simplify this. The lack of existing vision-based controlled systems, is the poor reliability of the

  20. Vision Based Autonomous Robot Navigation Algorithms and Implementations

    CERN Document Server

    Chatterjee, Amitava; Nirmal Singh, N

    2013-01-01

    This book is devoted to the theory and development of autonomous navigation of mobile robots using computer vision based sensing mechanism. The conventional robot navigation systems, utilizing traditional sensors like ultrasonic, IR, GPS, laser sensors etc., suffer several drawbacks related to either the physical limitations of the sensor or incur high cost. Vision sensing has emerged as a popular alternative where cameras can be used to reduce the overall cost, maintaining high degree of intelligence, flexibility and robustness. This book includes a detailed description of several new approaches for real life vision based autonomous navigation algorithms and SLAM. It presents the concept of how subgoal based goal-driven navigation can be carried out using vision sensing. The development concept of vision based robots for path/line tracking using fuzzy logic is presented, as well as how a low-cost robot can be indigenously developed in the laboratory with microcontroller based sensor systems. The book descri...

  1. Operational Based Vision Assessment Automated Vision Test Collection User Guide

    Science.gov (United States)

    2017-05-15

    in previous research ( Bach , Schmitt, Kromeier, & Kommerell, 2001). Providing an opportunity to practice is recommended to achieve more stable results...to another computer-based stereo acuity test described in previous research ( Bach , Schmitt, Kromeier, & Kommerell, 2001). Providing an opportunity...Distribution is unlimited. Cleared, 88PA, Case # 2017-2802, 6 Jun 2017. 8.0 REFERENCES Bach M, Schmitt C, Kromeier M, Kommerell G. The

  2. Exploiting Attitude Sensing in Vision-Based Navigation for an Airship

    Directory of Open Access Journals (Sweden)

    Luiz G. B. Mirisola

    2009-01-01

    Full Text Available An Attitude Heading Reference System (AHRS is used to compensate for rotational motion, facilitating vision-based navigation above smooth terrain by generating virtual images to simulate pure translation movement. The AHRS combines inertial and earth field magnetic sensors to provide absolute orientation measurements, and our recently developed calibration routine determines the rotation between the frames of reference of the AHRS and the monocular camera. In this way, the rotation is compensated, and the remaining translational motion is recovered by directly finding a rigid transformation to register corresponding scene coordinates. With a horizontal ground plane, the pure translation model performs more accurately than image-only approaches, and this is evidenced by recovering the trajectory of our airship UAV and comparing with GPS data. Visual odometry is also fused with the GPS, and ground plane maps are generated from the estimated vehicle poses and used to evaluate the results. Finally, loop closure is detected by looking for a previous image of the same area, and an open source SLAM package based in 3D graph optimization is employed to correct the visual odometry drift. The accuracy of the height estimation is also evaluated against ground truth in a controlled environment.

  3. Monocular 3D scene reconstruction at absolute scale

    Science.gov (United States)

    Wöhler, Christian; d'Angelo, Pablo; Krüger, Lars; Kuhl, Annika; Groß, Horst-Michael

    In this article we propose a method for combining geometric and real-aperture methods for monocular three-dimensional (3D) reconstruction of static scenes at absolute scale. Our algorithm relies on a sequence of images of the object acquired by a monocular camera of fixed focal setting from different viewpoints. Object features are tracked over a range of distances from the camera with a small depth of field, leading to a varying degree of defocus for each feature. Information on absolute depth is obtained based on a Depth-from-Defocus approach. The parameters of the point spread functions estimated by Depth-from-Defocus are used as a regularisation term for Structure-from-Motion. The reprojection error obtained from bundle adjustment and the absolute depth error obtained from Depth-from-Defocus are simultaneously minimised for all tracked object features. The proposed method yields absolutely scaled 3D coordinates of the scene points without any prior knowledge about scene structure and camera motion. We describe the implementation of the proposed method both as an offline and as an online algorithm. Evaluating the algorithm on real-world data, we demonstrate that it yields typical relative scale errors of a few per cent. We examine the influence of random effects, i.e. the noise of the pixel grey values, and systematic effects, caused by thermal expansion of the optical system or by inclusion of strongly blurred images, on the accuracy of the 3D reconstruction result. Possible applications of our approach are in the field of industrial quality inspection; in particular, it is preferable to stereo cameras in industrial vision systems with space limitations or where strong vibrations occur.

  4. Research on robot navigation vision sensor based on grating projection stereo vision

    Science.gov (United States)

    Zhang, Xiaoling; Luo, Yinsheng; Lin, Yuchi; Zhu, Lei

    2016-10-01

    A novel visual navigation method based on grating projection stereo vision for mobile robot in dark environment is proposed. This method is combining with grating projection profilometry of plane structured light and stereo vision technology. It can be employed to realize obstacle detection, SLAM (Simultaneous Localization and Mapping) and vision odometry for mobile robot navigation in dark environment without the image match in stereo vision technology and without phase unwrapping in the grating projection profilometry. First, we research the new vision sensor theoretical, and build geometric and mathematical model of the grating projection stereo vision system. Second, the computational method of 3D coordinates of space obstacle in the robot's visual field is studied, and then the obstacles in the field is located accurately. The result of simulation experiment and analysis shows that this research is useful to break the current autonomous navigation problem of mobile robot in dark environment, and to provide the theoretical basis and exploration direction for further study on navigation of space exploring robot in the dark and without GPS environment.

  5. Tundish Cover Flux Thickness Measurement Method and Instrumentation Based on Computer Vision in Continuous Casting Tundish

    Directory of Open Access Journals (Sweden)

    Meng Lu

    2013-01-01

    Full Text Available Thickness of tundish cover flux (TCF plays an important role in continuous casting (CC steelmaking process. Traditional measurement method of TCF thickness is single/double wire methods, which have several problems such as personal security, easily affected by operators, and poor repeatability. To solve all these problems, in this paper, we specifically designed and built an instrumentation and presented a novel method to measure the TCF thickness. The instrumentation was composed of a measurement bar, a mechanical device, a high-definition industrial camera, a Siemens S7-200 programmable logic controller (PLC, and a computer. Our measurement method was based on the computer vision algorithms, including image denoising method, monocular range measurement method, scale invariant feature transform (SIFT, and image gray gradient detection method. Using the present instrumentation and method, images in the CC tundish can be collected by camera and transferred to computer to do imaging processing. Experiments showed that our instrumentation and method worked well at scene of steel plants, can accurately measure the thickness of TCF, and overcome the disadvantages of traditional measurement methods, or even replace the traditional ones.

  6. Quantification and recognition of parkinsonian gait from monocular video imaging using kernel-based principal component analysis

    Directory of Open Access Journals (Sweden)

    Chen Shih-Wei

    2011-11-01

    Full Text Available Abstract Background The computer-aided identification of specific gait patterns is an important issue in the assessment of Parkinson's disease (PD. In this study, a computer vision-based gait analysis approach is developed to assist the clinical assessments of PD with kernel-based principal component analysis (KPCA. Method Twelve PD patients and twelve healthy adults with no neurological history or motor disorders within the past six months were recruited and separated according to their "Non-PD", "Drug-On", and "Drug-Off" states. The participants were asked to wear light-colored clothing and perform three walking trials through a corridor decorated with a navy curtain at their natural pace. The participants' gait performance during the steady-state walking period was captured by a digital camera for gait analysis. The collected walking image frames were then transformed into binary silhouettes for noise reduction and compression. Using the developed KPCA-based method, the features within the binary silhouettes can be extracted to quantitatively determine the gait cycle time, stride length, walking velocity, and cadence. Results and Discussion The KPCA-based method uses a feature-extraction approach, which was verified to be more effective than traditional image area and principal component analysis (PCA approaches in classifying "Non-PD" controls and "Drug-Off/On" PD patients. Encouragingly, this method has a high accuracy rate, 80.51%, for recognizing different gaits. Quantitative gait parameters are obtained, and the power spectrums of the patients' gaits are analyzed. We show that that the slow and irregular actions of PD patients during walking tend to transfer some of the power from the main lobe frequency to a lower frequency band. Our results indicate the feasibility of using gait performance to evaluate the motor function of patients with PD. Conclusion This KPCA-based method requires only a digital camera and a decorated corridor setup

  7. Vision-Based Leader Vehicle Trajectory Tracking for Multiple Agricultural Vehicles.

    Science.gov (United States)

    Zhang, Linhuan; Ahamed, Tofael; Zhang, Yan; Gao, Pengbo; Takigawa, Tomohiro

    2016-04-22

    The aim of this study was to design a navigation system composed of a human-controlled leader vehicle and a follower vehicle. The follower vehicle automatically tracks the leader vehicle. With such a system, a human driver can control two vehicles efficiently in agricultural operations. The tracking system was developed for the leader and the follower vehicle, and control of the follower was performed using a camera vision system. A stable and accurate monocular vision-based sensing system was designed, consisting of a camera and rectangular markers. Noise in the data acquisition was reduced by using the least-squares method. A feedback control algorithm was used to allow the follower vehicle to track the trajectory of the leader vehicle. A proportional-integral-derivative (PID) controller was introduced to maintain the required distance between the leader and the follower vehicle. Field experiments were conducted to evaluate the sensing and tracking performances of the leader-follower system while the leader vehicle was driven at an average speed of 0.3 m/s. In the case of linear trajectory tracking, the RMS errors were 6.5 cm, 8.9 cm and 16.4 cm for straight, turning and zigzag paths, respectively. Again, for parallel trajectory tracking, the root mean square (RMS) errors were found to be 7.1 cm, 14.6 cm and 14.0 cm for straight, turning and zigzag paths, respectively. The navigation performances indicated that the autonomous follower vehicle was able to follow the leader vehicle, and the tracking accuracy was found to be satisfactory. Therefore, the developed leader-follower system can be implemented for the harvesting of grains, using a combine as the leader and an unloader as the autonomous follower vehicle.

  8. Scene recognition for mine rescue robot localization based on vision

    Institute of Scientific and Technical Information of China (English)

    CUI Yi-an; CAI Zi-xing; WANG Lu

    2008-01-01

    A new scene recognition system was presented based on fuzzy logic and hidden Markov model(HMM) that can be applied in mine rescue robot localization during emergencies. The system uses monocular camera to acquire omni-directional images of the mine environment where the robot locates. By adopting center-surround difference method, the salient local image regions are extracted from the images as natural landmarks. These landmarks are organized by using HMM to represent the scene where the robot is, and fuzzy logic strategy is used to match the scene and landmark. By this way, the localization problem, which is the scene recognition problem in the system, can be converted into the evaluation problem of HMM. The contributions of these skills make the system have the ability to deal with changes in scale, 2D rotation and viewpoint. The results of experiments also prove that the system has higher ratio of recognition and localization in both static and dynamic mine environments.

  9. Reversible monocular cataract simulating amaurosis fugax.

    Science.gov (United States)

    Paylor, R R; Selhorst, J B; Weinberg, R S

    1985-07-01

    In a patient having brittle, juvenile-onset diabetes, transient monocular visual loss occurred repeatedly whenever there were wide fluctuations in serum glucose. Amaurosis fugax was suspected. The visual loss differed, however, in that it persisted over a period of hours to several days. Direct observation eventually revealed that the relatively sudden change in vision of one eye was associated with opacification of the lens and was not accompanied by an afferent pupillary defect. Presumably, a hyperosmotic gradient had developed with the accumulation of glucose and sorbitol within the lens. Water was drawn inward, altering the composition of the lens fibers and thereby lowering the refractive index, forming a reversible cataract. Hypoglycemia is also hypothesized to have played a role in the formation of a higher osmotic gradient. The unilaterality of the cataract is attributed to variation in the permeability of asymmetric posterior subcapsular cataracts.

  10. Gait disorder rehabilitation using vision and non-vision based sensors: a systematic review.

    Science.gov (United States)

    Ali, Asraf; Sundaraj, Kenneth; Ahmad, Badlishah; Ahamed, Nizam; Islam, Anamul

    2012-08-01

    Even though the amount of rehabilitation guidelines has never been greater, uncertainty continues to arise regarding the efficiency and effectiveness of the rehabilitation of gait disorders. This question has been hindered by the lack of information on accurate measurements of gait disorders. Thus, this article reviews the rehabilitation systems for gait disorder using vision and non-vision sensor technologies, as well as the combination of these. All papers published in the English language between 1990 and June, 2012 that had the phrases "gait disorder", "rehabilitation", "vision sensor", or "non vision sensor" in the title, abstract, or keywords were identified from the SpringerLink, ELSEVIER, PubMed, and IEEE databases. Some synonyms of these phrases and the logical words "and", "or", and "not" were also used in the article searching procedure. Out of the 91 published articles found, this review identified 84 articles that described the rehabilitation of gait disorders using different types of sensor technologies. This literature set presented strong evidence for the development of rehabilitation systems using a markerless vision-based sensor technology. We therefore believe that the information contained in this review paper will assist the progress of the development of rehabilitation systems for human gait disorders.

  11. Monocular Video Guided Garment Simulation

    Institute of Scientific and Technical Information of China (English)

    Fa-Ming Li; Xiao-Wu Chen∗; Bin Zhou; Fei-Xiang Lu; Kan Guo; Qiang Fu

    2015-01-01

    We present a prototype to generate a garment-shape sequence guided by a monocular video sequence. It is a combination of a physically-based simulation and a boundary-based modification. Given a garment in the video worn on a mannequin, the simulation generates a garment initial shape by exploiting the mannequin shapes estimated from the video. The modification then deforms the simulated 3D shape into such a shape that matches the garment 2D boundary extracted from the video. According to the matching correspondences between the vertices on the shape and the points on the boundary, the modification is implemented by attracting the matched vertices and their neighboring vertices. For best-matching correspondences and efficient performance, three criteria are introduced to select the candidate vertices for matching. Since modifying each garment shape independently may cause inter-frame oscillations, changes by the modification are also propagated from one frame to the next frame. As a result, the generated garment 3D shape sequence is stable and similar to the garment video sequence. We demonstrate the effectiveness of our prototype with a number of examples.

  12. Graph Structure-Based Simultaneous Localization and Mapping Using a Hybrid Method of 2D Laser Scan and Monocular Camera Image in Environments with Laser Scan Ambiguity.

    Science.gov (United States)

    Oh, Taekjun; Lee, Donghwa; Kim, Hyungjin; Myung, Hyun

    2015-07-03

    Localization is an essential issue for robot navigation, allowing the robot to perform tasks autonomously. However, in environments with laser scan ambiguity, such as long corridors, the conventional SLAM (simultaneous localization and mapping) algorithms exploiting a laser scanner may not estimate the robot pose robustly. To resolve this problem, we propose a novel localization approach based on a hybrid method incorporating a 2D laser scanner and a monocular camera in the framework of a graph structure-based SLAM. 3D coordinates of image feature points are acquired through the hybrid method, with the assumption that the wall is normal to the ground and vertically flat. However, this assumption can be relieved, because the subsequent feature matching process rejects the outliers on an inclined or non-flat wall. Through graph optimization with constraints generated by the hybrid method, the final robot pose is estimated. To verify the effectiveness of the proposed method, real experiments were conducted in an indoor environment with a long corridor. The experimental results were compared with those of the conventional GMappingapproach. The results demonstrate that it is possible to localize the robot in environments with laser scan ambiguity in real time, and the performance of the proposed method is superior to that of the conventional approach.

  13. Graph Structure-Based Simultaneous Localization and Mapping Using a Hybrid Method of 2D Laser Scan and Monocular Camera Image in Environments with Laser Scan Ambiguity

    Science.gov (United States)

    Oh, Taekjun; Lee, Donghwa; Kim, Hyungjin; Myung, Hyun

    2015-01-01

    Localization is an essential issue for robot navigation, allowing the robot to perform tasks autonomously. However, in environments with laser scan ambiguity, such as long corridors, the conventional SLAM (simultaneous localization and mapping) algorithms exploiting a laser scanner may not estimate the robot pose robustly. To resolve this problem, we propose a novel localization approach based on a hybrid method incorporating a 2D laser scanner and a monocular camera in the framework of a graph structure-based SLAM. 3D coordinates of image feature points are acquired through the hybrid method, with the assumption that the wall is normal to the ground and vertically flat. However, this assumption can be relieved, because the subsequent feature matching process rejects the outliers on an inclined or non-flat wall. Through graph optimization with constraints generated by the hybrid method, the final robot pose is estimated. To verify the effectiveness of the proposed method, real experiments were conducted in an indoor environment with a long corridor. The experimental results were compared with those of the conventional GMappingapproach. The results demonstrate that it is possible to localize the robot in environments with laser scan ambiguity in real time, and the performance of the proposed method is superior to that of the conventional approach. PMID:26151203

  14. Graph Structure-Based Simultaneous Localization and Mapping Using a Hybrid Method of 2D Laser Scan and Monocular Camera Image in Environments with Laser Scan Ambiguity

    Directory of Open Access Journals (Sweden)

    Taekjun Oh

    2015-07-01

    Full Text Available Localization is an essential issue for robot navigation, allowing the robot to perform tasks autonomously. However, in environments with laser scan ambiguity, such as long corridors, the conventional SLAM (simultaneous localization and mapping algorithms exploiting a laser scanner may not estimate the robot pose robustly. To resolve this problem, we propose a novel localization approach based on a hybrid method incorporating a 2D laser scanner and a monocular camera in the framework of a graph structure-based SLAM. 3D coordinates of image feature points are acquired through the hybrid method, with the assumption that the wall is normal to the ground and vertically flat. However, this assumption can be relieved, because the subsequent feature matching process rejects the outliers on an inclined or non-flat wall. Through graph optimization with constraints generated by the hybrid method, the final robot pose is estimated. To verify the effectiveness of the proposed method, real experiments were conducted in an indoor environment with a long corridor. The experimental results were compared with those of the conventional GMappingapproach. The results demonstrate that it is possible to localize the robot in environments with laser scan ambiguity in real time, and the performance of the proposed method is superior to that of the conventional approach.

  15. Is binocular vision worth considering in people with low vision?

    Science.gov (United States)

    Uzdrowska, Marta; Crossland, Michael; Broniarczyk-Loba, Anna

    2014-01-01

    In someone with good vision, binocular vision provides benefits which could not be obtained by monocular viewing only. People with visual impairment often have abnormal binocularity. However, they often use both eyes simultaneously in their everyday activities. Much remains to be known about binocular vision in people with visual impairment. As the binocular status of people with low vision strongly influences their treatment and rehabilitation, it should be evaluated and considered before diagnosis and further recommendations.

  16. Vision-based coaching: Optimizing resources for leader development

    Directory of Open Access Journals (Sweden)

    Angela M. Passarelli

    2015-04-01

    Full Text Available Leaders develop in the direction of their dreams, not in the direction of their deficits. Yet many coaching interactions intended to promote a leader’s development fail to leverage the developmental benefits of the individual’s personal vision. Drawing on Intentional Change Theory, this article postulates that coaching interactions that emphasize a leader’s personal vision (future aspirations and core identity evoke a psychophysiological state characterized by positive emotions, cognitive openness, and optimal neurobiological functioning for complex goal pursuit. Vision-based coaching, via this psychophysiological state, generates a host of relational and motivational resources critical to the developmental process. These resources include: formation of a positive coaching relationship, expansion of the leader’s identity, increased vitality, activation of learning goals, and a promotion-orientation. Organizational outcomes as well as limitations to vision-based coaching are discussed.

  17. Vision-based coaching: optimizing resources for leader development.

    Science.gov (United States)

    Passarelli, Angela M

    2015-01-01

    Leaders develop in the direction of their dreams, not in the direction of their deficits. Yet many coaching interactions intended to promote a leader's development fail to leverage the benefits of the individual's personal vision. Drawing on intentional change theory, this article postulates that coaching interactions that emphasize a leader's personal vision (future aspirations and core identity) evoke a psychophysiological state characterized by positive emotions, cognitive openness, and optimal neurobiological functioning for complex goal pursuit. Vision-based coaching, via this psychophysiological state, generates a host of relational and motivational resources critical to the developmental process. These resources include: formation of a positive coaching relationship, expansion of the leader's identity, increased vitality, activation of learning goals, and a promotion-orientation. Organizational outcomes as well as limitations to vision-based coaching are discussed.

  18. Surgical outcome in monocular elevation deficit: A retrospective interventional study

    Directory of Open Access Journals (Sweden)

    Bandyopadhyay Rakhi

    2008-01-01

    Full Text Available Background and Aim: Monocular elevation deficiency (MED is characterized by a unilateral defect in elevation, caused by paretic, restrictive or combined etiology. Treatment of this multifactorial entity is therefore varied. In this study, we performed different surgical procedures in patients of MED and evaluated their outcome, based on ocular alignment, improvement in elevation and binocular functions. Study Design: Retrospective interventional study. Materials and Methods: Twenty-eight patients were included in this study, from June 2003 to August 2006. Five patients underwent Knapp procedure, with or without horizontal squint surgery, 17 patients had inferior rectus recession, with or without horizontal squint surgery, three patients had combined inferior rectus recession and Knapp procedure and three patients had inferior rectus recession combined with contralateral superior rectus or inferior oblique surgery. The choice of procedure was based on the results of forced duction test (FDT. Results: Forced duction test was positive in 23 cases (82%. Twenty-four of 28 patients (86% were aligned to within 10 prism diopters. Elevation improved in 10 patients (36% from no elevation above primary position (-4 to only slight limitation of elevation (-1. Five patients had preoperative binocular vision and none gained it postoperatively. No significant postoperative complications or duction abnormalities were observed during the follow-up period. Conclusion: Management of MED depends upon selection of the correct surgical technique based on employing the results of FDT, for a satisfactory outcome.

  19. A new benchmark for stereo-based pedestrian detection

    NARCIS (Netherlands)

    C.G. Keller; M. Enzweiler; D.M. Gavrila

    2011-01-01

    Pedestrian detection is a rapidly evolving area in the intelligent vehicles domain. Stereo vision is an attractive sensor for this purpose. But unlike for monocular vision, there are no realistic, large scale benchmarks available for stereo-based pedestrian detection, to provide a common point of re

  20. A Behaviour-Based Architecture for Mapless Navigation Using Vision

    Directory of Open Access Journals (Sweden)

    Mehmet Serdar Guzel

    2012-04-01

    Full Text Available Autonomous robots operating in an unknown and uncertain environment must be able to cope with dynamic changes to that environment. For a mobile robot in a cluttered environment to navigate successfully to a goal while avoiding obstacles is a challenging problem. This paper presents a new behaviour based architecture design for mapless navigation. The architecture is composed of several modules and each module generates behaviours. A novel method, inspired from a visual homing strategy, is adapted to a monocular vision‐based system to overcome goal‐based navigation problems. A neural network‐based obstacle avoidance strategy is designed using a 2‐D scanning laser. To evaluate the performance of the proposed architecture, the system has been tested using Microsoft Robotics Studio (MRS, which is a very powerful 3D simulation environment. In addition, real experiments to guide a Pioneer 3‐DX mobile robot, equipped with a pan‐tilt‐zoom camera in a cluttered environment are presented. The analysis of the results allows us to validate the proposed behaviour‐ based navigation strategy.

  1. Learning Depth from Single Monocular Images Using Deep Convolutional Neural Fields.

    Science.gov (United States)

    Liu, Fayao; Shen, Chunhua; Lin, Guosheng; Reid, Ian

    2016-10-01

    In this article, we tackle the problem of depth estimation from single monocular images. Compared with depth estimation using multiple images such as stereo depth perception, depth from monocular images is much more challenging. Prior work typically focuses on exploiting geometric priors or additional sources of information, most using hand-crafted features. Recently, there is mounting evidence that features from deep convolutional neural networks (CNN) set new records for various vision applications. On the other hand, considering the continuous characteristic of the depth values, depth estimation can be naturally formulated as a continuous conditional random field (CRF) learning problem. Therefore, here we present a deep convolutional neural field model for estimating depths from single monocular images, aiming to jointly explore the capacity of deep CNN and continuous CRF. In particular, we propose a deep structured learning scheme which learns the unary and pairwise potentials of continuous CRF in a unified deep CNN framework. We then further propose an equally effective model based on fully convolutional networks and a novel superpixel pooling method, which is about 10 times faster, to speedup the patch-wise convolutions in the deep model. With this more efficient model, we are able to design deeper networks to pursue better performance. Our proposed method can be used for depth estimation of general scenes with no geometric priors nor any extra information injected. In our case, the integral of the partition function can be calculated in a closed form such that we can exactly solve the log-likelihood maximization. Moreover, solving the inference problem for predicting depths of a test image is highly efficient as closed-form solutions exist. Experiments on both indoor and outdoor scene datasets demonstrate that the proposed method outperforms state-of-the-art depth estimation approaches.

  2. A new combination of monocular and stereo cues for dense disparity estimation

    Science.gov (United States)

    Mao, Miao; Qin, Kaihuai

    2013-07-01

    Disparity estimation is a popular and important topic in computer vision and robotics. Stereo vision is commonly done to complete the task, but most existing methods fail in textureless regions and utilize numerical methods to interpolate into these regions. Monocular features are usually ignored, which may contain helpful depth information. We proposed a novel method combining monocular and stereo cues to compute dense disparities from a pair of images. The whole image regions are categorized into reliable regions (textured and unoccluded) and unreliable regions (textureless or occluded). Stable and accurate disparities can be gained at reliable regions. Then for unreliable regions, we utilize k-means to find the most similar reliable regions in terms of monocular cues. Our method is simple and effective. Experiments show that our method can generate a more accurate disparity map than existing methods from images with large textureless regions, e.g. snow, icebergs.

  3. 基于单目视觉的移动机器人伺服镇定控制%Monocular camera-based mobile robot visual servo regulation control

    Institute of Scientific and Technical Information of China (English)

    刘阳; 王忠立; 蔡伯根; 闻映红

    2016-01-01

    To solve the monocular camera‐based mobile robot regulation problem ,the kinematic model in camera coordinate was proposed under the condition of unknown range information ,unknown translation parameter between robot and camera frames ,camera with certain dip angle .A robust and adaptive controller was proposed based on the assumptions above .The controller guaranteed exponen‐tial convergence of the system .The performance of the controller was validated by simulation and ex‐periment result ,showing that the controller could guarantees the robot rapidly and smoothly regulate to desired pose .T he controller is also robust to unknow n parameter .%针对轮式移动机器人的单目视觉伺服镇定问题,在深度信息、机器人坐标系与摄像机坐标系间平移参量未知、摄像头光轴具有固定倾角的情况下,建立了移动机器人在摄像机坐标系下的运动模型。针对该模型提出了一种基于平面单应矩阵分解的鲁棒自适应控制方法,保证了误差的全局指数收敛。仿真和实验结果表明:所设计的控制器可以保证移动机器人指数收敛到期望的位姿,同时所设计的鲁棒自适应控制器对参数不确定性具有一定的鲁棒性。

  4. A Research on Monocular Visual SLAM Based on SURF Feature%基于SURF特征的单目视觉SLAM方法研究∗

    Institute of Scientific and Technical Information of China (English)

    胡衡; 梁岚珍

    2015-01-01

    Because the visual information is easily affected by external environment factors, therefore the selected feature points of mobile robot based on visual simultaneous localization and map building requires high stability and good robustness. For the problem of monocular visual mobile robot SLAM(Simultaneous Localization and Mapping),a kind of mono-SLAM algorithm based on Extended kalman filter is proposed by using SURF(Speed Up Robust Features) feature points and the inverse depth method. The process of SLAM is completed by fusing the information of SURF features and robot information with EKF. The result of simulation experiment indicates that the proposed algorithm is feasible, and with high localization precision in indoor structured environment.%由于视觉信息很容易受到外界环境因素的影响,因此基于视觉的移动机器人同步定位与地图构建问题所选取的特征点要求具有较高的精确度和良好的鲁棒性。针对单目SLAM问题,提出一种基于扩展卡尔曼滤波器的单目视觉SLAM算法。该算法采用SURF特征点,结合反向深度估计法,应用扩展卡尔曼滤波器融合SURF特征信息与机器人位姿信息完成SLAM过程。仿真实验结果表明,在未知室内结构化环境下,该算法运行可靠,定位精度高。

  5. Signal- and Symbol-based Representations in Computer Vision

    DEFF Research Database (Denmark)

    Krüger, Norbert; Felsberg, Michael

    We discuss problems of signal-- and symbol based representations in terms of three dilemmas which are faced in the design of each vision system. Signal- and symbol-based representations are opposite ends of a spectrum of conceivable design decisions caught at opposite sides of the dilemmas. We make...

  6. The prevalence and causes of decreased visual acuity – a study based on vision screening conducted at Enukweni and Mzuzu Foundation Primary Schools, Malawi

    Directory of Open Access Journals (Sweden)

    Thom L

    2016-12-01

    Full Text Available Leaveson Thom,1 Sanchia Jogessar,1,2 Sara L McGowan,1 Fiona Lawless,1,2 1Department of Optometry, Mzuzu University, Mzuzu, Malawi; 2Brienholden Vision Institute, Durban, South Africa Aim: To determine the prevalence and causes of decreased visual acuity (VA among pupils recruited in two primary schools in Mzimba district, northern region of Malawi.Materials and methods: The study was based on the vision screening which was conducted by optometrists at Enukweni and Mzuzu Foundation Primary Schools. The measurements during the screening included unaided distance monocular VA by using Low Vision Resource Center and Snellen chart, pinhole VA on any subject with VA of less than 6/6, refraction, pupil evaluations, ocular movements, ocular health, and shadow test.Results: The prevalence of decreased VA was found to be low in school-going population (4%, n=594. Even though Enukweni Primary School had few participants than Mzuzu Foundation Primary School, it had high prevalence of decreased VA (5.8%, n=275 than Mzuzu Foundation Primary School (1.8%, n=319. The principal causes of decreased VA in this study were found to be amblyopia and uncorrected refractive errors, with myopia being the main cause than hyperopia.Conclusion: Based on the low prevalence of decreased VA due to myopia or hyperopia, it should not be concluded that refractive errors are an insignificant contributor to visual disability in Malawi. More vision screenings are required at a large scale on school-aged population to reflect the real situation on the ground. Cost-effective strategies are needed to address this easily treatable cause of vision impairment. Keywords: vision screening, refractive errors, visual acuity, Enukweni, Mzuzu foundation

  7. Direction Identification System of Garlic Clove Based on Machine Vision

    Directory of Open Access Journals (Sweden)

    Gao Chi

    2013-05-01

    Full Text Available In order to fulfill the requirements of seeding direction of garlic cloves, the paper proposed a research method of garlic clove direction identification based on machine vision, it expounded the theory of garlic clove direction identification, stated the arithmetic of it, designed the direction identification device of it, then developed the control system of garlic clove direction identification based on machine vision, at last tested the garlic clove direction identification, and the result of the experiment certificated that the rate of garlic clove direction identification could reach to more than 97%, and it demonstrated that the research is of high feasibility and technological values.

  8. ERROR DETECTION BY ANTICIPATION FOR VISION-BASED CONTROL

    Directory of Open Access Journals (Sweden)

    A ZAATRI

    2001-06-01

    Full Text Available A vision-based control system has been developed.  It enables a human operator to remotely direct a robot, equipped with a camera, towards targets in 3D space by simply pointing on their images with a pointing device. This paper presents an anticipatory system, which has been designed for improving the safety and the effectiveness of the vision-based commands. It simulates these commands in a virtual environment. It attempts to detect hard contacts that may occur between the robot and its environment, which can be caused by machine errors or operator errors as well.

  9. A Laser-Based Vision System for Weld Quality Inspection

    Science.gov (United States)

    Huang, Wei; Kovacevic, Radovan

    2011-01-01

    Welding is a very complex process in which the final weld quality can be affected by many process parameters. In order to inspect the weld quality and detect the presence of various weld defects, different methods and systems are studied and developed. In this paper, a laser-based vision system is developed for non-destructive weld quality inspection. The vision sensor is designed based on the principle of laser triangulation. By processing the images acquired from the vision sensor, the geometrical features of the weld can be obtained. Through the visual analysis of the acquired 3D profiles of the weld, the presences as well as the positions and sizes of the weld defects can be accurately identified and therefore, the non-destructive weld quality inspection can be achieved. PMID:22344308

  10. Visual Peoplemeter: A Vision-based Television Audience Measurement System

    Directory of Open Access Journals (Sweden)

    SKELIN, A. K.

    2014-11-01

    Full Text Available Visual peoplemeter is a vision-based measurement system that objectively evaluates the attentive behavior for TV audience rating, thus offering solution to some of drawbacks of current manual logging peoplemeters. In this paper, some limitations of current audience measurement system are reviewed and a novel vision-based system aiming at passive metering of viewers is prototyped. The system uses camera mounted on a television as a sensing modality and applies advanced computer vision algorithms to detect and track a person, and to recognize attentional states. Feasibility of the system is evaluated on a secondary dataset. The results show that the proposed system can analyze viewer's attentive behavior, therefore enabling passive estimates of relevant audience measurement categories.

  11. Pose Estimation of a Mobile Robot Based on Fusion of IMU Data and Vision Data Using an Extended Kalman Filter.

    Science.gov (United States)

    Alatise, Mary B; Hancke, Gerhard P

    2017-09-21

    Using a single sensor to determine the pose estimation of a device cannot give accurate results. This paper presents a fusion of an inertial sensor of six degrees of freedom (6-DoF) which comprises the 3-axis of an accelerometer and the 3-axis of a gyroscope, and a vision to determine a low-cost and accurate position for an autonomous mobile robot. For vision, a monocular vision-based object detection algorithm speeded-up robust feature (SURF) and random sample consensus (RANSAC) algorithms were integrated and used to recognize a sample object in several images taken. As against the conventional method that depend on point-tracking, RANSAC uses an iterative method to estimate the parameters of a mathematical model from a set of captured data which contains outliers. With SURF and RANSAC, improved accuracy is certain; this is because of their ability to find interest points (features) under different viewing conditions using a Hessain matrix. This approach is proposed because of its simple implementation, low cost, and improved accuracy. With an extended Kalman filter (EKF), data from inertial sensors and a camera were fused to estimate the position and orientation of the mobile robot. All these sensors were mounted on the mobile robot to obtain an accurate localization. An indoor experiment was carried out to validate and evaluate the performance. Experimental results show that the proposed method is fast in computation, reliable and robust, and can be considered for practical applications. The performance of the experiments was verified by the ground truth data and root mean square errors (RMSEs).

  12. A Case of Functional (Psychogenic Monocular Hemianopia Analyzed by Measurement of Hemifield Visual Evoked Potentials

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Yoneda

    2013-12-01

    Full Text Available Purpose: Functional monocular hemianopia is an extremely rare condition, for which measurement of hemifield visual evoked potentials (VEPs has not been previously described. Methods: A 14-year-old boy with functional monocular hemianopia was followed up with Goldmann perimetry and measurement of hemifield and full-field VEPs. Results: The patient had a history of monocular temporal hemianopia of the right eye following headache, nausea and ague. There was no relative afferent pupillary defect, and a color perception test was normal. Goldmann perimetry revealed a vertical monocular temporal hemianopia of the right eye; the hemianopia on the right was also detected with a binocular visual field test. Computed tomography, magnetic resonance imaging (MRI and MR angiography of the brain including the optic chiasm as well as orbital MRI revealed no abnormalities. On the basis of these results, we diagnosed the patient's condition as functional monocular hemianopia. Pattern VEPs according to the International Society for Clinical Electrophysiology of Vision (ISCEV standard were within the normal range. The hemifield pattern VEPs for the right eye showed a symmetrical latency and amplitude for nasal and temporal hemifield stimulation. One month later, the visual field defect of the patient spontaneously disappeared. Conclusions: The latency and amplitude of hemifield VEPs for a patient with functional monocular hemianopia were normal. Measurement of hemifield VEPs may thus provide an objective tool for distinguishing functional hemianopia from hemifield loss caused by an organic lesion.

  13. On the Recognition-by-Components Approach Applied to Computer Vision

    Science.gov (United States)

    Baessmann, Henning; Besslich, Philipp W.

    1990-03-01

    The human visual system is usually able to recognize objects as well as their spatial relations without the support of depth information like stereo vision. For this reason we can easily understand cartoons, photographs and movies. It is the aim of our current research to exploit this aspect of human perception in the context of computer vision. From a monocular TV image we obtain information about the type of an object observed in the scene and its position relative to the camera (viewpoint). This paper deals with the theory of human image understanding as far as used in this system and describes the realization of a vision system based on these principles.

  14. Enhanced monocular visual odometry integrated with laser distance meter for astronaut navigation.

    Science.gov (United States)

    Wu, Kai; Di, Kaichang; Sun, Xun; Wan, Wenhui; Liu, Zhaoqin

    2014-03-11

    Visual odometry provides astronauts with accurate knowledge of their position and orientation. Wearable astronaut navigation systems should be simple and compact. Therefore, monocular vision methods are preferred over stereo vision systems, commonly used in mobile robots. However, the projective nature of monocular visual odometry causes a scale ambiguity problem. In this paper, we focus on the integration of a monocular camera with a laser distance meter to solve this problem. The most remarkable advantage of the system is its ability to recover a global trajectory for monocular image sequences by incorporating direct distance measurements. First, we propose a robust and easy-to-use extrinsic calibration method between camera and laser distance meter. Second, we present a navigation scheme that fuses distance measurements with monocular sequences to correct the scale drift. In particular, we explain in detail how to match the projection of the invisible laser pointer on other frames. Our proposed integration architecture is examined using a live dataset collected in a simulated lunar surface environment. The experimental results demonstrate the feasibility and effectiveness of the proposed method.

  15. Rapid matching of stereo vision based on fringe projection profilometry

    Science.gov (United States)

    Zhang, Ruihua; Xiao, Yi; Cao, Jian; Guo, Hongwei

    2016-09-01

    As the most important core part of stereo vision, there are still many problems to solve in stereo matching technology. For smooth surfaces on which feature points are not easy to extract, this paper adds a projector into stereo vision measurement system based on fringe projection techniques, according to the corresponding point phases which extracted from the left and right camera images are the same, to realize rapid matching of stereo vision. And the mathematical model of measurement system is established and the three-dimensional (3D) surface of the measured object is reconstructed. This measurement method can not only broaden application fields of optical 3D measurement technology, and enrich knowledge achievements in the field of optical 3D measurement, but also provide potential possibility for the commercialized measurement system in practical projects, which has very important scientific research significance and economic value.

  16. Current state of the art of vision based SLAM

    Science.gov (United States)

    Muhammad, Naveed; Fofi, David; Ainouz, Samia

    2009-02-01

    The ability of a robot to localise itself and simultaneously build a map of its environment (Simultaneous Localisation and Mapping or SLAM) is a fundamental characteristic required for autonomous operation of the robot. Vision Sensors are very attractive for application in SLAM because of their rich sensory output and cost effectiveness. Different issues are involved in the problem of vision based SLAM and many different approaches exist in order to solve these issues. This paper gives a classification of state-of-the-art vision based SLAM techniques in terms of (i) imaging systems used for performing SLAM which include single cameras, stereo pairs, multiple camera rigs and catadioptric sensors, (ii) features extracted from the environment in order to perform SLAM which include point features and line/edge features, (iii) initialisation of landmarks which can either be delayed or undelayed, (iv) SLAM techniques used which include Extended Kalman Filtering, Particle Filtering, biologically inspired techniques like RatSLAM, and other techniques like Local Bundle Adjustment, and (v) use of wheel odometry information. The paper also presents the implementation and analysis of stereo pair based EKF SLAM for synthetic data. Results prove the technique to work successfully in the presence of considerable amounts of sensor noise. We believe that state of the art presented in the paper can serve as a basis for future research in the area of vision based SLAM. It will permit further research in the area to be carried out in an efficient and application specific way.

  17. Vision communications based on LED array and imaging sensor

    Science.gov (United States)

    Yoo, Jong-Ho; Jung, Sung-Yoon

    2012-11-01

    In this paper, we propose a brand new communication concept, called as "vision communication" based on LED array and image sensor. This system consists of LED array as a transmitter and digital device which include image sensor such as CCD and CMOS as receiver. In order to transmit data, the proposed communication scheme simultaneously uses the digital image processing and optical wireless communication scheme. Therefore, the cognitive communication scheme is possible with the help of recognition techniques used in vision system. By increasing data rate, our scheme can use LED array consisting of several multi-spectral LEDs. Because arranged each LED can emit multi-spectral optical signal such as visible, infrared and ultraviolet light, the increase of data rate is possible similar to WDM and MIMO skills used in traditional optical and wireless communications. In addition, this multi-spectral capability also makes it possible to avoid the optical noises in communication environment. In our vision communication scheme, the data packet is composed of Sync. data and information data. Sync. data is used to detect the transmitter area and calibrate the distorted image snapshots obtained by image sensor. By making the optical rate of LED array be same with the frame rate (frames per second) of image sensor, we can decode the information data included in each image snapshot based on image processing and optical wireless communication techniques. Through experiment based on practical test bed system, we confirm the feasibility of the proposed vision communications based on LED array and image sensor.

  18. Vision Based Navigation Sensors for Spacecraft Rendezvous and Docking

    DEFF Research Database (Denmark)

    Benn, Mathias

    is a technological demonstration mission, where all aspects of space rendezvous and docking to both a cooperative and a non-cooperative target is researched, with the use of novel methods, instruments and technologies. Amongst other equipment, DTU has delivered a vision based sensor package to the Main spacecraft...

  19. Surface formation and depth in monocular scene perception.

    Science.gov (United States)

    Albert, M K

    1999-01-01

    The visual perception of monocular stimuli perceived as 3-D objects has received considerable attention from researchers in human and machine vision. However, most previous research has focused on how individual 3-D objects are perceived. Here this is extended to a study of how the structure of 3-D scenes containing multiple, possibly disconnected objects and features is perceived. Da Vinci stereopsis, stereo capture, and other surface formation and interpolation phenomena in stereopsis and structure-from-motion suggest that small features having ambiguous depth may be assigned depth by interpolation with features having unambiguous depth. I investigated whether vision may use similar mechanisms to assign relative depth to multiple objects and features in sparse monocular images, such as line drawings, especially when other depth cues are absent. I propose that vision tends to organize disconnected objects and features into common surfaces to construct 3-D-scene interpretations. Interpolations that are too weak to generate a visible surface percept may still be strong enough to assign relative depth to objects within a scene. When there exists more than one possible surface interpolation in a scene, the visual system's preference for one interpolation over another seems to be influenced by a number of factors, including: (i) proximity, (ii) smoothness, (iii) a preference for roughly frontoparallel surfaces and 'ground' surfaces, (iv) attention and fixation, and (v) higher-level factors. I present a variety of demonstrations and an experiment to support this surface-formation hypothesis.

  20. Parallax error in the monocular head-mounted eye trackers

    DEFF Research Database (Denmark)

    Mardanbeigi, Diako; Witzner Hansen, Dan

    2012-01-01

    This paper investigates the parallax error, which is a common problem of many video-based monocular mobile gaze trackers. The parallax error is defined and described using the epipolar geometry in a stereo camera setup. The main parameters that change the error are introduced and it is shown how...

  1. Water-based Tourism - A Strategic Vision for Galway

    OpenAIRE

    Institute, Marine

    2002-01-01

    Water-based Tourism – A Strategic Vision for Galway is a report commissioned by a consortium of Agencies in collaboration with Ireland West Tourism. The terms of reference were to undertake a study which would: - evaluate the potential to develop the water-based tourism and leisure resource in Galway City and County; - identify the potential and provide a development strategy for at least six pilot water-based tourism and leisure initiatives in selected geographic locations throughout Galway;...

  2. A Multistep Framework for Vision Based Vehicle Detection

    Directory of Open Access Journals (Sweden)

    Hai Wang

    2014-01-01

    Full Text Available Vision based vehicle detection is a critical technology that plays an important role in not only vehicle active safety but also road video surveillance application. In this work, a multistep framework for vision based vehicle detection is proposed. In the first step, for vehicle candidate generation, a novel geometrical and coarse depth information based method is proposed. In the second step, for candidate verification, a deep architecture of deep belief network (DBN for vehicle classification is trained. In the last step, a temporal analysis method based on the complexity and spatial information is used to further reduce miss and false detection. Experiments demonstrate that this framework is with high true positive (TP rate as well as low false positive (FP rate. On road experimental results demonstrate that the algorithm performs better than state-of-the-art vehicle detection algorithm in testing data sets.

  3. Automatic building detection based on Purposive FastICA (PFICA) algorithm using monocular high resolution Google Earth images

    Science.gov (United States)

    Ghaffarian, Saman; Ghaffarian, Salar

    2014-11-01

    This paper proposes an improved FastICA model named as Purposive FastICA (PFICA) with initializing by a simple color space transformation and a novel masking approach to automatically detect buildings from high resolution Google Earth imagery. ICA and FastICA algorithms are defined as Blind Source Separation (BSS) techniques for unmixing source signals using the reference data sets. In order to overcome the limitations of the ICA and FastICA algorithms and make them purposeful, we developed a novel method involving three main steps: 1-Improving the FastICA algorithm using Moore-Penrose pseudo inverse matrix model, 2-Automated seeding of the PFICA algorithm based on LUV color space and proposed simple rules to split image into three regions; shadow + vegetation, baresoil + roads and buildings, respectively, 3-Masking out the final building detection results from PFICA outputs utilizing the K-means clustering algorithm with two number of clusters and conducting simple morphological operations to remove noises. Evaluation of the results illustrates that buildings detected from dense and suburban districts with divers characteristics and color combinations using our proposed method have 88.6% and 85.5% overall pixel-based and object-based precision performances, respectively.

  4. Monocular SLAM for Autonomous Robots with Enhanced Features Initialization

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2014-04-01

    Full Text Available This work presents a variant approach to the monocular SLAM problem focused in exploiting the advantages of a human-robot interaction (HRI framework. Based upon the delayed inverse-depth feature initialization SLAM (DI-D SLAM, a known monocular technique, several but crucial modifications are introduced taking advantage of data from a secondary monocular sensor, assuming that this second camera is worn by a human. The human explores an unknown environment with the robot, and when their fields of view coincide, the cameras are considered a pseudo-calibrated stereo rig to produce estimations for depth through parallax. These depth estimations are used to solve a related problem with DI-D monocular SLAM, namely, the requirement of a metric scale initialization through known artificial landmarks. The same process is used to improve the performance of the technique when introducing new landmarks into the map. The convenience of the approach taken to the stereo estimation, based on SURF features matching, is discussed. Experimental validation is provided through results from real data with results showing the improvements in terms of more features correctly initialized, with reduced uncertainty, thus reducing scale and orientation drift. Additional discussion in terms of how a real-time implementation could take advantage of this approach is provided.

  5. Monocular SLAM for autonomous robots with enhanced features initialization.

    Science.gov (United States)

    Guerra, Edmundo; Munguia, Rodrigo; Grau, Antoni

    2014-04-02

    This work presents a variant approach to the monocular SLAM problem focused in exploiting the advantages of a human-robot interaction (HRI) framework. Based upon the delayed inverse-depth feature initialization SLAM (DI-D SLAM), a known monocular technique, several but crucial modifications are introduced taking advantage of data from a secondary monocular sensor, assuming that this second camera is worn by a human. The human explores an unknown environment with the robot, and when their fields of view coincide, the cameras are considered a pseudo-calibrated stereo rig to produce estimations for depth through parallax. These depth estimations are used to solve a related problem with DI-D monocular SLAM, namely, the requirement of a metric scale initialization through known artificial landmarks. The same process is used to improve the performance of the technique when introducing new landmarks into the map. The convenience of the approach taken to the stereo estimation, based on SURF features matching, is discussed. Experimental validation is provided through results from real data with results showing the improvements in terms of more features correctly initialized, with reduced uncertainty, thus reducing scale and orientation drift. Additional discussion in terms of how a real-time implementation could take advantage of this approach is provided.

  6. Signal- and Symbol-based Representations in Computer Vision

    DEFF Research Database (Denmark)

    Krüger, Norbert; Felsberg, Michael

    We discuss problems of signal-- and symbol based representations in terms of three dilemmas which are faced in the design of each vision system. Signal- and symbol-based representations are opposite ends of a spectrum of conceivable design decisions caught at opposite sides of the dilemmas. We make...... inherent problems explicit and describe potential design decisions for artificial visual systems to deal with the dilemmas....

  7. Teleoperation of a Team of Robots with Vision

    Science.gov (United States)

    2010-11-01

    of five to fifty monocular mobile robots that are jointly controlled by a single user with a joystick. Each robot communicates with nearby robots...effort, we focused on the image sensing opportunities provided by such a team of monocular mobile robots and the computer vision capabilities required to

  8. Rehabilitation regimes based upon psychophysical studies of prosthetic vision

    Science.gov (United States)

    Chen, S. C.; Suaning, G. J.; Morley, J. W.; Lovell, N. H.

    2009-06-01

    Human trials of prototype visual prostheses have successfully elicited visual percepts (phosphenes) in the visual field of implant recipients blinded through retinitis pigmentosa and age-related macular degeneration. Researchers are progressing rapidly towards a device that utilizes individual phosphenes as the elementary building blocks to compose a visual scene. This form of prosthetic vision is expected, in the near term, to have low resolution, large inter-phosphene gaps, distorted spatial distribution of phosphenes, restricted field of view, an eccentrically located phosphene field and limited number of expressible luminance levels. In order to fully realize the potential of these devices, there needs to be a training and rehabilitation program which aims to assist the prosthesis recipients to understand what they are seeing, and also to adapt their viewing habits to optimize the performance of the device. Based on the literature of psychophysical studies in simulated and real prosthetic vision, this paper proposes a comprehensive, theoretical training regime for a prosthesis recipient: visual search, visual acuity, reading, face/object recognition, hand-eye coordination and navigation. The aim of these tasks is to train the recipients to conduct visual scanning, eccentric viewing and reading, discerning low-contrast visual information, and coordinating bodily actions for visual-guided tasks under prosthetic vision. These skills have been identified as playing an important role in making prosthetic vision functional for the daily activities of their recipients.

  9. Vision-based vehicle detection and tracking algorithm design

    Science.gov (United States)

    Hwang, Junyeon; Huh, Kunsoo; Lee, Donghwi

    2009-12-01

    The vision-based vehicle detection in front of an ego-vehicle is regarded as promising for driver assistance as well as for autonomous vehicle guidance. The feasibility of vehicle detection in a passenger car requires accurate and robust sensing performance. A multivehicle detection system based on stereo vision has been developed for better accuracy and robustness. This system utilizes morphological filter, feature detector, template matching, and epipolar constraint techniques in order to detect the corresponding pairs of vehicles. After the initial detection, the system executes the tracking algorithm for the vehicles. The proposed system can detect front vehicles such as the leading vehicle and side-lane vehicles. The position parameters of the vehicles located in front are obtained based on the detection information. The proposed vehicle detection system is implemented on a passenger car, and its performance is verified experimentally.

  10. Model-based vision using geometric hashing

    Science.gov (United States)

    Akerman, Alexander, III; Patton, Ronald

    1991-04-01

    The Geometric Hashing technique developed by the NYU Courant Institute has been applied to various automatic target recognition applications. In particular, I-MATH has extended the hashing algorithm to perform automatic target recognition ofsynthetic aperture radar (SAR) imagery. For this application, the hashing is performed upon the geometric locations of dominant scatterers. In addition to being a robust model-based matching algorithm -- invariant under translation, scale, and 3D rotations of the target -- hashing is of particular utility because it can still perform effective matching when the target is partially obscured. Moreover, hashing is very amenable to a SIMD parallel processing architecture, and thus potentially realtime implementable.

  11. Evaluation of Sift and Surf for Vision Based Localization

    Science.gov (United States)

    Qu, Xiaozhi; Soheilian, Bahman; Habets, Emmanuel; Paparoditis, Nicolas

    2016-06-01

    Vision based localization is widely investigated for the autonomous navigation and robotics. One of the basic steps of vision based localization is the extraction of interest points in images that are captured by the embedded camera. In this paper, SIFT and SURF extractors were chosen to evaluate their performance in localization. Four street view image sequences captured by a mobile mapping system, were used for the evaluation and both SIFT and SURF were tested on different image scales. Besides, the impact of the interest point distribution was also studied. We evaluated the performances from for aspects: repeatability, precision, accuracy and runtime. The local bundle adjustment method was applied to refine the pose parameters and the 3D coordinates of tie points. According to the results of our experiments, SIFT was more reliable than SURF. Apart from this, both the accuracy and the efficiency of localization can be improved if the distribution of feature points are well constrained for SIFT.

  12. Practical vision based degraded text recognition system

    Science.gov (United States)

    Mohammad, Khader; Agaian, Sos; Saleh, Hani

    2011-02-01

    Rapid growth and progress in the medical, industrial, security and technology fields means more and more consideration for the use of camera based optical character recognition (OCR) Applying OCR to scanned documents is quite mature, and there are many commercial and research products available on this topic. These products achieve acceptable recognition accuracy and reasonable processing times especially with trained software, and constrained text characteristics. Even though the application space for OCR is huge, it is quite challenging to design a single system that is capable of performing automatic OCR for text embedded in an image irrespective of the application. Challenges for OCR systems include; images are taken under natural real world conditions, Surface curvature, text orientation, font, size, lighting conditions, and noise. These and many other conditions make it extremely difficult to achieve reasonable character recognition. Performance for conventional OCR systems drops dramatically as the degradation level of the text image quality increases. In this paper, a new recognition method is proposed to recognize solid or dotted line degraded characters. The degraded text string is localized and segmented using a new algorithm. The new method was implemented and tested using a development framework system that is capable of performing OCR on camera captured images. The framework allows parameter tuning of the image-processing algorithm based on a training set of camera-captured text images. Novel methods were used for enhancement, text localization and the segmentation algorithm which enables building a custom system that is capable of performing automatic OCR which can be used for different applications. The developed framework system includes: new image enhancement, filtering, and segmentation techniques which enabled higher recognition accuracies, faster processing time, and lower energy consumption, compared with the best state of the art published

  13. An autonomous vision-based mobile robot

    Science.gov (United States)

    Baumgartner, Eric Thomas

    This dissertation describes estimation and control methods for use in the development of an autonomous mobile robot for structured environments. The navigation of the mobile robot is based on precise estimates of the position and orientation of the robot within its environment. The extended Kalman filter algorithm is used to combine information from the robot's drive wheels with periodic observations of small, wall-mounted, visual cues to produce the precise position and orientation estimates. The visual cues are reliably detected by at least one video camera mounted on the mobile robot. Typical position estimates are accurate to within one inch. A path tracking algorithm is also developed to follow desired reference paths which are taught by a human operator. Because of the time-independence of the tracking algorithm, the speed that the vehicle travels along the reference path is specified independent from the tracking algorithm. The estimation and control methods have been applied successfully to two experimental vehicle systems. Finally, an analysis of the linearized closed-loop control system is performed to study the behavior and the stability of the system as a function of various control parameters.

  14. A real time vehicles detection algorithm for vision based sensors

    CERN Document Server

    Płaczek, Bartłomiej

    2011-01-01

    A vehicle detection plays an important role in the traffic control at signalised intersections. This paper introduces a vision-based algorithm for vehicles presence recognition in detection zones. The algorithm uses linguistic variables to evaluate local attributes of an input image. The image attributes are categorised as vehicle, background or unknown features. Experimental results on complex traffic scenes show that the proposed algorithm is effective for a real-time vehicles detection.

  15. Vision-based formation control of mobile robots

    Institute of Scientific and Technical Information of China (English)

    Shicai LIU; Dalong TAN; Guangjun LIU

    2005-01-01

    In this paper,a formation control algorithm and an obstacle avoidance control algorithm for mobile robots are developed based on a relative motion sensory system such as a pan/tilt camera vision system,without the need for global sensing and communication between robots.This is achieved by employing the velocity variation,instead of actual velocities,as the control inputs.Simulation and experimental results have demonstrated the effectiveness of the proposed control methods.

  16. Computer vision based nacre thickness measurement of Tahitian pearls

    Science.gov (United States)

    Loesdau, Martin; Chabrier, Sébastien; Gabillon, Alban

    2017-03-01

    The Tahitian Pearl is the most valuable export product of French Polynesia contributing with over 61 million Euros to more than 50% of the total export income. To maintain its excellent reputation on the international market, an obligatory quality control for every pearl deemed for exportation has been established by the local government. One of the controlled quality parameters is the pearls nacre thickness. The evaluation is currently done manually by experts that are visually analyzing X-ray images of the pearls. In this article, a computer vision based approach to automate this procedure is presented. Even though computer vision based approaches for pearl nacre thickness measurement exist in the literature, the very specific features of the Tahitian pearl, namely the large shape variety and the occurrence of cavities, have so far not been considered. The presented work closes the. Our method consists of segmenting the pearl from X-ray images with a model-based approach, segmenting the pearls nucleus with an own developed heuristic circle detection and segmenting possible cavities with region growing. Out of the obtained boundaries, the 2-dimensional nacre thickness profile can be calculated. A certainty measurement to consider imaging and segmentation imprecisions is included in the procedure. The proposed algorithms are tested on 298 manually evaluated Tahitian pearls, showing that it is generally possible to automatically evaluate the nacre thickness of Tahitian pearls with computer vision. Furthermore the results show that the automatic measurement is more precise and faster than the manual one.

  17. Laser vision sensing based on adaptive welding for aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhixiang; SONG Yonglun; ZHANG Jun; ZHANG Wanchun; JIANG Li; XIA Xuxin

    2007-01-01

    A laser vision sensing based on the adaptive tungsten inert gas(TIG)welding system for large-scale aluminum alloy components was established to fit various weld groove conditions.A new type of laser vision sensor was used to precisely measure the weld groove.The joint geometry data,such as the bevel angle,the gap,the area,and the mismatch,etc.,aided in assembling large-scale aerospace components before welding.They were also applied for automatic seam tracking,such as automatic torch transverse alignment and torch height adjustment in welding.An adaptive welding process was realized by automatically adjusting the wire feeding speed and the welding current according to the groove conditions.The process results in a good weld formation and high welding quality,which meet the requirements of related standards.

  18. Vision-based method for tracking meat cuts in slaughterhouses

    DEFF Research Database (Denmark)

    Larsen, Anders Boesen Lindbo; Hviid, Marchen Sonja; Engbo Jørgensen, Mikkel

    2014-01-01

    Meat traceability is important for linking process and quality parameters from the individual meat cuts back to the production data from the farmer that produced the animal. Current tracking systems rely on physical tagging, which is too intrusive for individual meat cuts in a slaughterhouse...... environment. In this article, we demonstrate a computer vision system for recognizing meat cuts at different points along a slaughterhouse production line. More specifically, we show that 211 pig loins can be identified correctly between two photo sessions. The pig loins undergo various perturbation scenarios...... (hanging, rough treatment and incorrect trimming) and our method is able to handle these perturbations gracefully. This study shows that the suggested vision-based approach to tracking is a promising alternative to the more intrusive methods currently available....

  19. Vision Sensor-Based Road Detection for Field Robot Navigation.

    Science.gov (United States)

    Lu, Keyu; Li, Jian; An, Xiangjing; He, Hangen

    2015-11-24

    Road detection is an essential component of field robot navigation systems. Vision sensors play an important role in road detection for their great potential in environmental perception. In this paper, we propose a hierarchical vision sensor-based method for robust road detection in challenging road scenes. More specifically, for a given road image captured by an on-board vision sensor, we introduce a multiple population genetic algorithm (MPGA)-based approach for efficient road vanishing point detection. Superpixel-level seeds are then selected in an unsupervised way using a clustering strategy. Then, according to the GrowCut framework, the seeds proliferate and iteratively try to occupy their neighbors. After convergence, the initial road segment is obtained. Finally, in order to achieve a globally-consistent road segment, the initial road segment is refined using the conditional random field (CRF) framework, which integrates high-level information into road detection. We perform several experiments to evaluate the common performance, scale sensitivity and noise sensitivity of the proposed method. The experimental results demonstrate that the proposed method exhibits high robustness compared to the state of the art.

  20. Vision Sensor-Based Road Detection for Field Robot Navigation

    Directory of Open Access Journals (Sweden)

    Keyu Lu

    2015-11-01

    Full Text Available Road detection is an essential component of field robot navigation systems. Vision sensors play an important role in road detection for their great potential in environmental perception. In this paper, we propose a hierarchical vision sensor-based method for robust road detection in challenging road scenes. More specifically, for a given road image captured by an on-board vision sensor, we introduce a multiple population genetic algorithm (MPGA-based approach for efficient road vanishing point detection. Superpixel-level seeds are then selected in an unsupervised way using a clustering strategy. Then, according to the GrowCut framework, the seeds proliferate and iteratively try to occupy their neighbors. After convergence, the initial road segment is obtained. Finally, in order to achieve a globally-consistent road segment, the initial road segment is refined using the conditional random field (CRF framework, which integrates high-level information into road detection. We perform several experiments to evaluate the common performance, scale sensitivity and noise sensitivity of the proposed method. The experimental results demonstrate that the proposed method exhibits high robustness compared to the state of the art.

  1. An egocentric vision based assistive co-robot.

    Science.gov (United States)

    Zhang, Jingzhe; Zhuang, Lishuo; Wang, Yang; Zhou, Yameng; Meng, Yan; Hua, Gang

    2013-06-01

    We present the prototype of an egocentric vision based assistive co-robot system. In this co-robot system, the user is wearing a pair of glasses with a forward looking camera, and is actively engaged in the control loop of the robot in navigational tasks. The egocentric vision glasses serve for two purposes. First, it serves as a source of visual input to request the robot to find a certain object in the environment. Second, the motion patterns computed from the egocentric video associated with a specific set of head movements are exploited to guide the robot to find the object. These are especially helpful for quadriplegic individuals who do not have needed hand functionality for interaction and control with other modalities (e.g., joystick). In our co-robot system, when the robot does not fulfill the object finding task in a pre-specified time window, it would actively solicit user controls for guidance. Then the users can use the egocentric vision based gesture interface to orient the robot towards the direction of the object. After that the robot will automatically navigate towards the object until it finds it. Our experiments validated the efficacy of the closed-loop design to engage the human in the loop.

  2. Sphere-based calibration method for trinocular vision sensor

    Science.gov (United States)

    Lu, Rui; Shao, Mingwei

    2017-03-01

    A new method to calibrate a trinocular vision sensor is proposed and two main tasks are finished in this paper, i.e. to determine the transformation matrix between each two cameras and the trifocal tensor of the trinocular vision sensor. A flexible sphere target with several spherical circles is designed. As the isotropy of a sphere, trifocal tensor of the three cameras can be determined exactly from the feature on the sphere target. Then the fundamental matrix between each two cameras can be obtained. Easily, compatible rotation matrix and translation matrix can be deduced base on the singular value decomposition of the fundamental matrix. In our proposed calibration method, image points are not requested one-to-one correspondence. When image points locates in the same feature are obtained, the transformation matrix between each two cameras with the trifocal tensor of trinocular vision sensor can be determined. Experiment results show that the proposed calibration method can obtain precise results, including measurement and matching results. The root mean square error of distance is 0.026 mm with regard to the view field of about 200×200 mm and the feature matching of three images is strict. As a sphere projection is not concerned with its orientation, the calibration method is robust and with an easy operation. Moreover, our calibration method also provides a new approach to obtain the trifocal tensor.

  3. Trinocular stereo vision method based on mesh candidates

    Science.gov (United States)

    Liu, Bin; Xu, Gang; Li, Haibin

    2010-10-01

    One of the most interesting goals of machine vision is 3D structure recovery of the scenes. This recovery has many applications, such as object recognition, reverse engineering, automatic cartography, autonomous robot navigation, etc. To meet the demand of measuring the complex prototypes in reverse engineering, a trinocular stereo vision method based on mesh candidates was proposed. After calibration of the cameras, the joint field of view can be defined in the world coordinate system. Mesh grid is established along the coordinate axes, and the mesh nodes are considered as potential depth data of the object surface. By similarity measure of the correspondence pairs which are projected from a certain group of candidates, the depth data can be obtained readily. With mesh nodes optimization, the interval between the neighboring nodes in depth direction could be designed reasonably. The potential ambiguity can be eliminated efficiently in correspondence matching with the constraint of a third camera. The cameras can be treated as two independent pairs, left-right and left-centre. Due to multiple peaks of the correlation values, the binocular method may not satisfy the accuracy of the measurement. Another image pair is involved if the confidence coefficient is less than the preset threshold. The depth is determined by the highest sum of correlation of both camera pairs. The measurement system was simulated using 3DS MAX and Matlab software for reconstructing the surface of the object. The experimental result proved that the trinocular vision system has good performance in depth measurement.

  4. Simulation Platform for Vision Aided Inertial Navigation

    Science.gov (United States)

    2014-09-18

    canyons, indoors or underground. It is also possible for a GPS signal to be jammed. This weakness motivates the development of alternate navigation ...Johnson, E. N., Magree, D., Wu, A., & Shein, A. (2013). "GPS‐Denied Indoor and Outdoor Monocular Vision Aided Navigation and Control of Unmanned...SIMULATION PLATFORM FOR VISION AIDED INERTIAL NAVIGATION THESIS SEPTEMBER 2014 Jason Gek

  5. Object-oriented vision for a behavior-based robot

    Science.gov (United States)

    Bischoff, Rainer; Graefe, Volker; Wershofen, Klaus P.

    1996-10-01

    As one realization out of the class of behavior-based robot architectures a specific concept of situation-oriented behavior-based navigation has been proposed. Its main characteristic is that the selection of the behaviors to be executed in each moment is based on a continuous recognition and evaluation of the dynamically changing situation in which the robot is finding itself. An important prerequisite for such as approach is a timely and comprehensive perception of the robot's dynamically changing environment. Object-oriented vision as proposed and successfully applied, e.g., in freeway traffic scenes is a particularly well suited sensing modality for robot control. Our work concentrated on modeling the physical objects which are relevant for indoor navigation, i.e. walls, intersections of corridors, and landmarks. In the interest of efficiency these models include only those necessary features for allowing the robot to reliably recognize different situations in real time. According to the concept of object- oriented vision recognizing such objects is largely reduced to a knowledge-based verification of objects or features that may be expected to be visible in the current situation. The following results have been achieved: 1) By using its vision system and a knowledge base in the form of an attributed topological map the robot could orient itself and navigate autonomously in a known environment. 2) In an unknown environment the robot was able to build, by means of supervised learning, an attributed topological map as a basis for subsequent autonomous navigation. 3) The experiments could be performed both under unmodified artificial light and under natural light shining through the glass walls of the building.

  6. P2-1: Visual Short-Term Memory Lacks Sensitivity to Stereoscopic Depth Changes but is Much Sensitive to Monocular Depth Changes

    Directory of Open Access Journals (Sweden)

    Hae-In Kang

    2012-10-01

    Full Text Available Depth from both binocular disparity and monocular depth cues presumably is one of most salient features that would characterize a variety of visual objects in our daily life. Therefore it is plausible to expect that human vision should be good at perceiving objects' depth change arising from binocular disparities and monocular pictorial cues. However, what if the estimated depth needs to be remembered in visual short-term memory (VSTM rather than just perceived? In a series of experiments, we asked participants to remember depth of items in an array at the beginning of each trial. A set of test items followed after the memory array, and the participants were asked to report if one of the items in the test array have changed its depth from the remembered items or not. The items would differ from each other in three different depth conditions: (1 stereoscopic depth under binocular disparity manipulations, (2 monocular depth under pictorial cue manipulations, and (3 both stereoscopic and monocular depth. The accuracy of detecting depth change was substantially higher in the monocular condition than in the binocular condition, and the accuracy in the both-depth condition was moderately improved compared to the monocular condition. These results indicate that VSTM benefits more from monocular depth than stereoscopic depth, and further suggests that storage of depth information into VSTM would require both binocular and monocular information for its optimal memory performance.

  7. A Vision-based Approach to Fire Detection

    Directory of Open Access Journals (Sweden)

    Pedro Gomes

    2014-09-01

    Full Text Available This paper presents a vision-based method for fire detection from fixed surveillance smart cameras. The method integrates several well-known techniques properly adapted to cope with the challenges related to the actual deployment of the vision system. Concretely, background subtraction is performed with a context-based learning mechanism so as to attain higher accuracy and robustness. The computational cost of a frequency analysis of potential fire regions is reduced by means of focusing its operation with an attentive mechanism. For fast discrimination between fire regions and fire-coloured moving objects, a new colour-based model of fire’s appearance and a new wavelet-based model of fire’s frequency signature are proposed. To reduce the false alarm rate due to the presence of fire-coloured moving objects, the category and behaviour of each moving object is taken into account in the decision-making. To estimate the expected object’s size in the image plane and to generate geo-referenced alarms, the camera-world mapping is approximated with a GPS-based calibration process. Experimental results demonstrate the ability of the proposed method to detect fires with an average success rate of 93.1 % at a processing rate of 10 Hz, which is often sufficient for real-life applications.

  8. A Vision-Based Approach to Fire Detection

    Directory of Open Access Journals (Sweden)

    Pedro Gomes

    2014-09-01

    Full Text Available This paper presents a vision-based method for fire detection from fixed surveillance smart cameras. The method integrates several well-known techniques properly adapted to cope with the challenges related to the actual deployment of the vision system. Concretely, background subtraction is performed with a context-based learning mechanism so as to attain higher accuracy and robustness. The computational cost of a frequency analysis of potential fire regions is reduced by means of focusing its operation with an attentive mechanism. For fast discrimination between fire regions and fire-coloured moving objects, a new colour-based model of fire's appearance and a new wavelet-based model of fire's frequency signature are proposed. To reduce the false alarm rate due to the presence of fire-coloured moving objects, the category and behaviour of each moving object is taken into account in the decision-making. To estimate the expected object's size in the image plane and to generate geo-referenced alarms, the camera-world mapping is approximated with a GPS-based calibration process. Experimental results demonstrate the ability of the proposed method to detect fires with an average success rate of 93.1% at a processing rate of 10 Hz, which is often sufficient for real-life applications.

  9. Reference Sphere Positioning Measurement Based on Line-Structured Light Vision Sensor

    OpenAIRE

    2013-01-01

    The line-structured light vision sensor has been used widely in industrial vision measuring fields due to its simple structure, small volume, light weight, low cost, convenient calibration, and high accuracy of measurement. To locate the reference sphere precisely with line-structured light vision sensor, a mathematical model based on the measuring principle of line-structured light vision sensor is established in the paper. Then, the positioning measurement error is analyzed in detail. The e...

  10. Blobs versus bars: psychophysical evidence supports two types of orientation response in human color vision.

    Science.gov (United States)

    Gheiratmand, Mina; Meese, Tim S; Mullen, Kathy T

    2013-01-02

    The classic hypothesis of Livingstone and Hubel (1984, 1987) proposed two types of color pathways in primate visual cortex based on recordings from single cells: a segregated, modular pathway that signals color but provides little information about shape or form and a second pathway that signals color differences and so defines forms without the need to specify their colors. A major problem has been to reconcile this neurophysiological hypothesis with the behavioral data. A wealth of psychophysical studies has demonstrated that color vision has orientation-tuned responses and little impairment on form related tasks, but these have not revealed any direct evidence for nonoriented mechanisms. Here we use a psychophysical method of subthreshold summation across orthogonal orientations for isoluminant red-green gratings in monocular and dichoptic viewing conditions to differentiate between nonoriented and orientation-tuned responses to color contrast. We reveal nonoriented color responses at low spatial frequencies (0.25-0.375 c/deg) under monocular conditions changing to orientation-tuned responses at higher spatial frequencies (1.5 c/deg) and under binocular conditions. We suggest that two distinct pathways coexist in color vision at the behavioral level, revealed at different spatial scales: one is isotropic, monocular, and best equipped for the representation of surface color, and the other is orientation-tuned, binocular, and selective for shape and form. This advances our understanding of the organization of the neural pathways involved in human color vision and provides a strong link between neurophysiological and behavioral data.

  11. Vision-based recursive estimation of rotorcraft obstacle locations

    Science.gov (United States)

    Leblanc, D. J.; Mcclamroch, N. H.

    1992-01-01

    The authors address vision-based passive ranging during nap-of-the-earth (NOE) rotorcraft flight. They consider the problem of estimating the relative location of identifiable features on nearby obstacles, assuming a sequence of noisy camera images and imperfect measurements of the camera's translation and rotation. An iterated extended Kalman filter is used to provide recursive range estimation. The correspondence problem is simplified by predicting and tracking each feature's image within the Kalman filter framework. Simulation results are presented which show convergent estimates and generally successful feature point tracking. Estimation performance degrades for features near the optical axis and for accelerating motions. Image tracking is also sensitive to angular rate.

  12. EyeScreen: A Vision-Based Gesture Interaction System

    Institute of Scientific and Technical Information of China (English)

    LI Shan-qing; XU Yi-hua; JIA Yun-de

    2007-01-01

    EyeScreen is a vision-based interaction system which provides a natural gesture interface for human-computer interaction (HCI) by tracking human fingers and recognizing gestures. Multi-view video images are captured by two cameras facing a computer screen, which can be used to detect clicking actions of a fingertip and improve the recognition rate. The system enables users to directly interact with rendered objects on the screen. Robustness of the system has been verified by extensive experiments with different user scenarios. EyeScreen can be used in many applications such as intelligent interaction and digital entertainment.

  13. Vision-based Human Gender Recognition: A Survey

    CERN Document Server

    Ng, Choon Boon; Goi, Bok Min

    2012-01-01

    Gender is an important demographic attribute of people. This paper provides a survey of human gender recognition in computer vision. A review of approaches exploiting information from face and whole body (either from a still image or gait sequence) is presented. We highlight the challenges faced and survey the representative methods of these approaches. Based on the results, good performance have been achieved for datasets captured under controlled environments, but there is still much work that can be done to improve the robustness of gender recognition under real-life environments.

  14. Machine Learning for Vision-Based Motion Analysis

    CERN Document Server

    Wang, Liang; Cheng, Li; Pietikainen, Matti

    2011-01-01

    Techniques of vision-based motion analysis aim to detect, track, identify, and generally understand the behavior of objects in image sequences. With the growth of video data in a wide range of applications from visual surveillance to human-machine interfaces, the ability to automatically analyze and understand object motions from video footage is of increasing importance. Among the latest developments in this field is the application of statistical machine learning algorithms for object tracking, activity modeling, and recognition. Developed from expert contributions to the first and second In

  15. Design of vision-based soccer robot using DSP

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new design of vision-based soccer robot using the type TMS320F240 of DSPs for MiroSot series is presented. The DSP used enables cost-effective control of DC motor, and features fewer external components, lower system cost and better performances than traditional microcontroller. The hardware architecture of robot is firstly presented in detail, and then the software design is briefly discussed. The control structure of decision making subsystem is illuminated also in this paper. The conclusion and prospect are given at last.

  16. Accurate measurement method for tube's endpoints based on machine vision

    Science.gov (United States)

    Liu, Shaoli; Jin, Peng; Liu, Jianhua; Wang, Xiao; Sun, Peng

    2017-01-01

    Tubes are used widely in aerospace vehicles, and their accurate assembly can directly affect the assembling reliability and the quality of products. It is important to measure the processed tube's endpoints and then fix any geometric errors correspondingly. However, the traditional tube inspection method is time-consuming and complex operations. Therefore, a new measurement method for a tube's endpoints based on machine vision is proposed. First, reflected light on tube's surface can be removed by using photometric linearization. Then, based on the optimization model for the tube's endpoint measurements and the principle of stereo matching, the global coordinates and the relative distance of the tube's endpoint are obtained. To confirm the feasibility, 11 tubes are processed to remove the reflected light and then the endpoint's positions of tubes are measured. The experiment results show that the measurement repeatability accuracy is 0.167 mm, and the absolute accuracy is 0.328 mm. The measurement takes less than 1 min. The proposed method based on machine vision can measure the tube's endpoints without any surface treatment or any tools and can realize on line measurement.

  17. Accurate Measurement Method for Tube's Endpoints Based on Machine Vision

    Institute of Scientific and Technical Information of China (English)

    LIU Shaoli; JIN Peng; LIU Jianhua; WANG Xiao; SUN Peng

    2017-01-01

    Tubes are used widely in aerospace vehicles,and their accurate assembly can directly affect the assembling reliability and the quality of products.It is important to measure the processed tube's endpoints and then fix any geometric errors correspondingly.However,the traditional tube inspection method is time-consuming and complex operations.Therefore,a new measurement method for a tube's endpoints based on machine vision is proposed.First,reflected light on tube's surface can be removed by using photometric linearization.Then,based on the optimization model for the tube's endpoint measurements and the principle of stereo matching,the global coordinates and the relative distance of the tube's endpoint are obtained.To confirm the feasibility,11 tubes are processed to remove the reflected light and then the endpoint's positions of tubes are measured.The experiment results show that the measurement repeatability accuracy is 0.167 mm,and the absolute accuracy is 0.328 mm.The measurement takes less than 1 min.The proposed method based on machine vision can measure the tube's endpoints without any surface treatment or any tools and can realize on line measurement.

  18. Accurate measurement method for tube's endpoints based on machine vision

    Science.gov (United States)

    Liu, Shaoli; Jin, Peng; Liu, Jianhua; Wang, Xiao; Sun, Peng

    2016-08-01

    Tubes are used widely in aerospace vehicles, and their accurate assembly can directly affect the assembling reliability and the quality of products. It is important to measure the processed tube's endpoints and then fix any geometric errors correspondingly. However, the traditional tube inspection method is time-consuming and complex operations. Therefore, a new measurement method for a tube's endpoints based on machine vision is proposed. First, reflected light on tube's surface can be removed by using photometric linearization. Then, based on the optimization model for the tube's endpoint measurements and the principle of stereo matching, the global coordinates and the relative distance of the tube's endpoint are obtained. To confirm the feasibility, 11 tubes are processed to remove the reflected light and then the endpoint's positions of tubes are measured. The experiment results show that the measurement repeatability accuracy is 0.167 mm, and the absolute accuracy is 0.328 mm. The measurement takes less than 1 min. The proposed method based on machine vision can measure the tube's endpoints without any surface treatment or any tools and can realize on line measurement.

  19. Research into the Architecture of CAD Based Robot Vision Systems

    Science.gov (United States)

    1988-02-09

    Vision 󈨚 and "Automatic Generation of Recognition Features for Com- puter Vision," Mudge, Turney and Volz, published in Robotica (1987). All of the...Occluded Parts," (T.N. Mudge, J.L. Turney, and R.A. Volz), Robotica , vol. 5, 1987, pp. 117-127. 5. "Vision Algorithms for Hypercube Machines," (T.N. Mudge

  20. 单目视觉同步定位与地图创建方法综述%A survey of monocular simultaneous localization and mapping

    Institute of Scientific and Technical Information of China (English)

    顾照鹏; 刘宏

    2015-01-01

    随着计算机视觉技术的发展,基于单目视觉的同步定位与地图创建( monocular SLAM)逐渐成为计算机视觉领域的热点问题之一。介绍了单目视觉SLAM方法的分类,从视觉特征检测与匹配、数据关联的优化、特征点深度的获取、地图的尺度控制几个方面阐述了单目视觉SLAM研究的发展现状。最后,介绍了常见的单目视觉与其他传感器结合的SLAM方法,并探讨了单目视觉SLAM未来的研究方向。%With the development of computer vision technology, monocular simultaneous localization and mapping ( monocular SLAM) has gradually become one of the hot issues in the field of computer vision.This paper intro-duces the monocular vision SLAM classification that relates to the present status of research in monocular SLAM methods from several aspects, including visual feature detection and matching, optimization of data association, depth acquisition of feature points, and map scale control.Monocular SLAM methods combining with other sensors are reviewed and significant issues needing further study are discussed.

  1. Dataflow-Based Mapping of Computer Vision Algorithms onto FPGAs

    Directory of Open Access Journals (Sweden)

    Schlessman Jason

    2007-01-01

    Full Text Available We develop a design methodology for mapping computer vision algorithms onto an FPGA through the use of coarse-grain reconfigurable dataflow graphs as a representation to guide the designer. We first describe a new dataflow modeling technique called homogeneous parameterized dataflow (HPDF, which effectively captures the structure of an important class of computer vision applications. This form of dynamic dataflow takes advantage of the property that in a large number of image processing applications, data production and consumption rates can vary, but are equal across dataflow graph edges for any particular application iteration. After motivating and defining the HPDF model of computation, we develop an HPDF-based design methodology that offers useful properties in terms of verifying correctness and exposing performance-enhancing transformations; we discuss and address various challenges in efficiently mapping an HPDF-based application representation into target-specific HDL code; and we present experimental results pertaining to the mapping of a gesture recognition application onto the Xilinx Virtex II FPGA.

  2. Improving Car Navigation with a Vision-Based System

    Science.gov (United States)

    Kim, H.; Choi, K.; Lee, I.

    2015-08-01

    The real-time acquisition of the accurate positions is very important for the proper operations of driver assistance systems or autonomous vehicles. Since the current systems mostly depend on a GPS and map-matching technique, they show poor and unreliable performance in blockage and weak areas of GPS signals. In this study, we propose a vision oriented car navigation method based on sensor fusion with a GPS and in-vehicle sensors. We employed a single photo resection process to derive the position and attitude of the camera and thus those of the car. This image georeferencing results are combined with other sensory data under the sensor fusion framework for more accurate estimation of the positions using an extended Kalman filter. The proposed system estimated the positions with an accuracy of 15 m although GPS signals are not available at all during the entire test drive of 15 minutes. The proposed vision based system can be effectively utilized for the low-cost but high-accurate and reliable navigation systems required for intelligent or autonomous vehicles.

  3. Improving CAR Navigation with a Vision-Based System

    Science.gov (United States)

    Kim, H.; Choi, K.; Lee, I.

    2015-08-01

    The real-time acquisition of the accurate positions is very important for the proper operations of driver assistance systems or autonomous vehicles. Since the current systems mostly depend on a GPS and map-matching technique, they show poor and unreliable performance in blockage and weak areas of GPS signals. In this study, we propose a vision oriented car navigation method based on sensor fusion with a GPS and in-vehicle sensors. We employed a single photo resection process to derive the position and attitude of the camera and thus those of the car. This image georeferencing results are combined with other sensory data under the sensor fusion framework for more accurate estimation of the positions using an extended Kalman filter. The proposed system estimated the positions with an accuracy of 15 m although GPS signals are not available at all during the entire test drive of 15 minutes. The proposed vision based system can be effectively utilized for the low-cost but high-accurate and reliable navigation systems required for intelligent or autonomous vehicles.

  4. IMPROVING CAR NAVIGATION WITH A VISION-BASED SYSTEM

    Directory of Open Access Journals (Sweden)

    H. Kim

    2015-08-01

    Full Text Available The real-time acquisition of the accurate positions is very important for the proper operations of driver assistance systems or autonomous vehicles. Since the current systems mostly depend on a GPS and map-matching technique, they show poor and unreliable performance in blockage and weak areas of GPS signals. In this study, we propose a vision oriented car navigation method based on sensor fusion with a GPS and in-vehicle sensors. We employed a single photo resection process to derive the position and attitude of the camera and thus those of the car. This image georeferencing results are combined with other sensory data under the sensor fusion framework for more accurate estimation of the positions using an extended Kalman filter. The proposed system estimated the positions with an accuracy of 15 m although GPS signals are not available at all during the entire test drive of 15 minutes. The proposed vision based system can be effectively utilized for the low-cost but high-accurate and reliable navigation systems required for intelligent or autonomous vehicles.

  5. A Highest Order Hypothesis Compatibility Test for Monocular SLAM

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2013-08-01

    Full Text Available Simultaneous Location and Mapping (SLAM is a key problem to solve in order to build truly autonomous mobile robots. SLAM with a unique camera, or monocular SLAM, is probably one of the most complex SLAM variants, based entirely on a bearing-only sensor working over six DOF. The monocular SLAM method developed in this work is based on the Delayed Inverse-Depth (DI-D Feature Initialization, with the contribution of a new data association batch validation technique, the Highest Order Hypothesis Compatibility Test, HOHCT. The Delayed Inverse-Depth technique is used to initialize new features in the system and defines a single hypothesis for the initial depth of features with the use of a stochastic technique of triangulation. The introduced HOHCT method is based on the evaluation of statistically compatible hypotheses and a search algorithm designed to exploit the strengths of the Delayed Inverse- Depth technique to achieve good performance results. This work presents the HOHCT with a detailed formulation of the monocular DI-D SLAM problem. The performance of the proposed HOHCT is validated with experimental results, in both indoor and outdoor environments, while its costs are compared with other popular approaches.

  6. A Highest Order Hypothesis Compatibility Test for Monocular SLAM

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2013-08-01

    Full Text Available Simultaneous Location and Mapping (SLAM is a key problem to solve in order to build truly autonomous mobile robots. SLAM with a unique camera, or monocular SLAM, is probably one of the most complex SLAM variants, based entirely on a bearing-only sensor working over six DOF. The monocular SLAM method developed in this work is based on the Delayed Inverse-Depth (DI-D Feature Initialization, with the contribution of a new data association batch validation technique, the Highest Order Hypothesis Compatibility Test, HOHCT. The Delayed Inverse-Depth technique is used to initialize new features in the system and defines a single hypothesis for the initial depth of features with the use of a stochastic technique of triangulation. The introduced HOHCT method is based on the evaluation of statistically compatible hypotheses and a search algorithm designed to exploit the strengths of the Delayed Inverse-Depth technique to achieve good performance results. This work presents the HOHCT with a detailed formulation of the monocular DI-D SLAM problem. The performance of the proposed HOHCT is validated with experimental results, in both indoor and outdoor environments, while its costs are compared with other popular approaches.

  7. A stereo vision-based obstacle detection system in vehicles

    Science.gov (United States)

    Huh, Kunsoo; Park, Jaehak; Hwang, Junyeon; Hong, Daegun

    2008-02-01

    Obstacle detection is a crucial issue for driver assistance systems as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision with the front vehicle. The vision-based obstacle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, an obstacle detection system using stereo vision sensors is developed. This system utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs. After the initial detection, the system executes the tracking algorithm for the obstacles. The proposed system can detect a front obstacle, a leading vehicle and a vehicle cutting into the lane. Then, the position parameters of the obstacles and leading vehicles can be obtained. The proposed obstacle detection system is implemented on a passenger car and its performance is verified experimentally.

  8. Vision-based multiple vehicle detection and tracking at nighttime

    Science.gov (United States)

    Xu, Wencong; Liu, Hai

    2011-08-01

    In this paper, we develop a robust vision-based approach for real-time traffic data collection at nighttime. The proposed algorithm detects and tracks vehicles through detection and location of vehicle headlights. First, we extract headlights candidates by an adaptive image segmentation algorithm. Then we group headlights candidates that belong to the same vehicle by spatial clustering and generate vehicle hypotheses by rule-based reasoning. The potential vehicles are then tracked over frames by region search and pattern analysis methods. The spatial and temporal continuity extracted from tracking process is used to confirm vehicle's presence. To handle problem of occlusions, we apply Kalman Filter to motion estimation. We test the algorithm on the video clips of nighttime traffic under different conditions. The experimental results show that real-time vehicle counting and tacking for multi-lanes are achieved and the total detection rate is above 96%.

  9. The role of vision in perching and grasping for MAVs

    Science.gov (United States)

    Thomas, Justin; Loianno, Giuseppe; Daniilidis, Kostas; Kumar, Vijay

    2016-05-01

    In this work, we provide an overview of vision-based control for perching and grasping for Micro Aerial Vehicles. We investigate perching on at, inclined, or vertical surfaces as well as visual servoing techniques for quadrotors to enable autonomous perching by hanging from cylindrical structures using only a monocular camera and an appropriate gripper. The challenges of visual servoing are discussed, and we focus on the problems of relative pose estimation, control, and trajectory planning for maneuvering a robot with respect to an object of interest. Finally, we discuss future challenges to achieve fully autonomous perching and grasping in more realistic scenarios.

  10. Vision-based level control for beverage-filling processes

    Science.gov (United States)

    Ley, Dietmar; Braune, Ingolf

    1994-11-01

    This paper presents a vision-based on-line level control system which is used in beverage filling machines. Motivation for the development of this sensor system was the need for an intelligent filling valve, which can provide constant filling levels for all container/product combinations (i.e. juice, milk, beer, water, etc. in glass or PET bottles with various transparency and shape) by using a non-tactile and completely sterile measurement method. The sensor concept being presented in this paper is based on several CCD-cameras imaging the moving containers from the outside. The stationary lighting system illuminating the bottles is located within the filler circle. The field of view covers between 5 and 8 bottles depending on the bottle diameter and the filler partitioning. Each filling element's number is identified by the signals of an angular encoder. The electro-pneumatic filling valves can be opened and closed by computer control The cameras continuously monitor the final stages of the filling process, i.e. after the filling height has reached the upper half of the bottle. The sensor system measures the current filling height and derives the filling speed. Based on static a priori- knowledge and dynamic process knowledge the sensor system generates a best estimate of the particular time when the single valve is to be closed. After every new level measurement the system updates the closing time. The measurement process continues until the result of the next level calculation would be available after the estimated closing time would have been passed. The vision-based filling valve control enables the filling machine to adapt the filling time of each valve to the individual bottle shape. Herewith a standard deviation between 2 and 4 mm (depending on the slew rate in the bottle neck) can be accomplished, even at filling speed > 70.000 bottles per hour. 0

  11. High Accuracy Monocular SFM and Scale Correction for Autonomous Driving.

    Science.gov (United States)

    Song, Shiyu; Chandraker, Manmohan; Guest, Clark C

    2016-04-01

    We present a real-time monocular visual odometry system that achieves high accuracy in real-world autonomous driving applications. First, we demonstrate robust monocular SFM that exploits multithreading to handle driving scenes with large motions and rapidly changing imagery. To correct for scale drift, we use known height of the camera from the ground plane. Our second contribution is a novel data-driven mechanism for cue combination that allows highly accurate ground plane estimation by adapting observation covariances of multiple cues, such as sparse feature matching and dense inter-frame stereo, based on their relative confidences inferred from visual data on a per-frame basis. Finally, we demonstrate extensive benchmark performance and comparisons on the challenging KITTI dataset, achieving accuracy comparable to stereo and exceeding prior monocular systems. Our SFM system is optimized to output pose within 50 ms in the worst case, while average case operation is over 30 fps. Our framework also significantly boosts the accuracy of applications like object localization that rely on the ground plane.

  12. Robotic Arm Control Algorithm Based on Stereo Vision Using RoboRealm Vision

    Directory of Open Access Journals (Sweden)

    SZABO, R.

    2015-05-01

    Full Text Available The goal of this paper is to present a stereo computer vision algorithm intended to control a robotic arm. Specific points on the robot joints are marked and recognized in the software. Using a dedicated set of mathematic equations, the movement of the robot is continuously computed and monitored with webcams. Positioning error is finally analyzed.

  13. A Solar Position Sensor Based on Image Vision

    Science.gov (United States)

    Ruelas, Adolfo; Velázquez, Nicolás; Villa-Angulo, Carlos; Rosales, Pedro; Suastegui, José

    2017-01-01

    Solar collector technologies operate with better performance when the Sun beam direction is normal to the capturing surface, and for that to happen despite the relative movement of the Sun, solar tracking systems are used, therefore, there are rules and standards that need minimum accuracy for these tracking systems to be used in solar collectors’ evaluation. Obtaining accuracy is not an easy job, hence in this document the design, construction and characterization of a sensor based on a visual system that finds the relative azimuth error and height of the solar surface of interest, is presented. With these characteristics, the sensor can be used as a reference in control systems and their evaluation. The proposed sensor is based on a microcontroller with a real-time clock, inertial measurement sensors, geolocation and a vision sensor, that obtains the angle of incidence from the sunrays’ direction as well as the tilt and sensor position. The sensor’s characterization proved how a measurement of a focus error or a Sun position can be made, with an accuracy of 0.0426° and an uncertainty of 0.986%, which can be modified to reach an accuracy under 0.01°. The validation of this sensor was determined showing the focus error on one of the best commercial solar tracking systems, a Kipp & Zonen SOLYS 2. To conclude, the solar tracking sensor based on a vision system meets the Sun detection requirements and components that meet the accuracy conditions to be used in solar tracking systems and their evaluation or, as a tracking and orientation tool, on photovoltaic installations and solar collectors. PMID:28758935

  14. Bilateral symmetry in vision and influence of ocular surgical procedures on binocular vision: A topical review.

    Science.gov (United States)

    Arba Mosquera, Samuel; Verma, Shwetabh

    2016-01-01

    We analyze the role of bilateral symmetry in enhancing binocular visual ability in human eyes, and further explore how efficiently bilateral symmetry is preserved in different ocular surgical procedures. The inclusion criterion for this review was strict relevance to the clinical questions under research. Enantiomorphism has been reported in lower order aberrations, higher order aberrations and cone directionality. When contrast differs in the two eyes, binocular acuity is better than monocular acuity of the eye that receives higher contrast. Anisometropia has an uncommon occurrence in large populations. Anisometropia seen in infancy and childhood is transitory and of little consequence for the visual acuity. Binocular summation of contrast signals declines with age, independent of inter-ocular differences. The symmetric associations between the right and left eye could be explained by the symmetry in pupil offset and visual axis which is always nasal in both eyes. Binocular summation mitigates poor visual performance under low luminance conditions and strong inter-ocular disparity detrimentally affects binocular summation. Considerable symmetry of response exists in fellow eyes of patients undergoing myopic PRK and LASIK, however the method to determine whether or not symmetry is maintained consist of comparing individual terms in a variety of ad hoc ways both before and after the refractive surgery, ignoring the fact that retinal image quality for any individual is based on the sum of all terms. The analysis of bilateral symmetry should be related to the patients' binocular vision status. The role of aberrations in monocular and binocular vision needs further investigation.

  15. A Vision-Based Wireless Charging System for Robot Trophallaxis

    Directory of Open Access Journals (Sweden)

    Jae-O Kim

    2015-12-01

    Full Text Available The need to recharge the batteries of a mobile robot has presented an important challenge for a long time. In this paper, a vision-based wireless charging method for robot energy trophallaxis between two robots is presented. Even though wireless power transmission allows more positional error between receiver-transmitter coils than with a contact-type charging system, both coils have to be aligned as accurately as possible for efficient power transfer. To align the coils, a transmitter robot recognizes the coarse pose of a receiver robot via a camera image and the ambiguity of the estimated pose is removed with a Bayesian estimator. The precise pose of the receiver coil is calculated using a marker image attached to a receiver robot. Experiments with several types of receiver robots have been conducted to verify the proposed method.

  16. A novel vision-based PET bottle recycling facility

    Science.gov (United States)

    He, Xiangyu; He, Zaixing; Zhang, Shuyou; Zhao, Xinyue

    2017-02-01

    Post-consumer PET bottle recycling is attracting increasing attention due to its value as an energy conservation and environmental protection measure. Sorting by color is a common method in bottle recycling; however, manual operations are unstable and time consuming. In this paper, we design a vision-based facility to perform high-speed bottle sorting. The proposed facility consists mainly of electric and mechanical hardware and image processing software. To solve the recognition problem of isolated and overlapped bottles, we propose a new shape descriptor and utilize the support vector data description classifier. We use color names to represent the colors in the real world in order to avoid problems introduced by colors that are similar. The facility is evaluated by the target error, outlier error and total error. The experimental results demonstrate that the facility we developed is capable of recycling various PET bottles.

  17. Low Cost Vision Based Personal Mobile Mapping System

    Directory of Open Access Journals (Sweden)

    M. M. Amami

    2014-03-01

    Full Text Available Mobile mapping systems (MMS can be used for several purposes, such as transportation, highway infrastructure mapping and GIS data collecting. However, the acceptance of these systems is not wide spread and their use is still limited due the high cost and dependency on the Global Navigation Satellite System (GNSS. A low cost vision based personal MMS has been produced with an aim to overcome these limitations. The system has been designed to depend mainly on cameras and use of low cost GNSS and inertial sensors to provide a bundle adjustment solution with initial values. The system has the potential to be used indoor and outdoor. The system has been tested indoors and outdoors with different GPS coverage, surrounded features, and narrow and curvy paths. Tests show that the system is able to work in such environments providing 3D coordinates of better than 10 cm accuracy.

  18. Laser vision based adaptive fill control system for TIG welding

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The variation of joint groove size during tungsten inert gas (TIG) welding will result in the non-uniform fill of deposited metal. To solve this problem, an adaptive fill control system was developed based on laser vision sensing. The system hardware consists of a modular development kit (MDK) as the real-time image capturing system, a computer as the controller, a D/A conversion card as the interface of controlled variable output, and a DC TIG welding system as the controlled device. The system software is developed and the developed feature extraction algorithm and control strategy are of good accuracy and robustness. Experimental results show that the system can implement adaptive fill of melting metal with high stability, reliability and accuracy. The groove is filled well and the quality of the weld formation satisfies the relevant industry criteria.

  19. Computer Vision-Based Image Analysis of Bacteria.

    Science.gov (United States)

    Danielsen, Jonas; Nordenfelt, Pontus

    2017-01-01

    Microscopy is an essential tool for studying bacteria, but is today mostly used in a qualitative or possibly semi-quantitative manner often involving time-consuming manual analysis. It also makes it difficult to assess the importance of individual bacterial phenotypes, especially when there are only subtle differences in features such as shape, size, or signal intensity, which is typically very difficult for the human eye to discern. With computer vision-based image analysis - where computer algorithms interpret image data - it is possible to achieve an objective and reproducible quantification of images in an automated fashion. Besides being a much more efficient and consistent way to analyze images, this can also reveal important information that was previously hard to extract with traditional methods. Here, we present basic concepts of automated image processing, segmentation and analysis that can be relatively easy implemented for use with bacterial research.

  20. Brake Pedal Displacement Measuring System based on Machine Vision

    Directory of Open Access Journals (Sweden)

    Chang Wang

    2013-10-01

    Full Text Available Displacement of brake pedal was an important characteristic of driving behavior. This paper proposed a displacement measure algorithm based on machine vision. Image of brake pedal was captured by camera from left side, and images were processed in industry computer. Firstly, average smooth algorithm and wavelet transform algorithm were used to smooth the original image consecutively. Then, edge extracting method which combined Roberts’s operator with wavelet analysis was used to identify the edge of brake pedal. At last, least square method was adopted to recognize the characteristic line of brake pedal’s displacement. The experimental results demonstrated that the proposed method takes the advantages of Roberts’s operator and wavelet transform, it can obtain better measurement result as well as linear displacement sensors

  1. Machine vision inspection of rice seed based on Hough transform

    Institute of Scientific and Technical Information of China (English)

    成芳; 应义斌

    2004-01-01

    A machine vision system was developed to inspect the quality of rice seeds. Five varieties of Jinyou402, Shanyou10, Zhongyou207, Jiayou and IIyou were evaluated. The images of both sides of rice seed with black background and white background were acquired with the image processing system for identifying external features of rice seeds. Five image sets consisting of 600 original images each were obtained. Then a digital image processing algorithm based on Hough transform was developed to inspect the rice seeds with incompletely closed glumes. The algorithm was implemented with all image sets using a Matlab 6.5 procedure. The results showed that the algorithm achieved an average accuracy of 96% for normal seeds, 92% for seeds with fine fissure and 87% for seeds with incompletely closed glumes. The algorithm was proved to be applicable to different seed varieties and insensitive to the color of the background.

  2. Machine vision inspection of rice seed based on Hough transform

    Institute of Scientific and Technical Information of China (English)

    成芳; 应义斌

    2004-01-01

    A machine vision system was developed to inspect the quality of rice seeds. Five varieties of Jinyou402,Shanyou 10, Zhongyou207, Jiayou and Ilyou were evaluated. The images of both sides of rice seed with black background and white background were acquired with the image processing system for identifying external features of rice seeds. Five image sets consisting of 600 original images each were obtained. Then a digital image processing algorithm based on Hough transform was developed to inspect the rice seeds with incompletely closed glumes. The algorithm was implemented with all image sets using a Matlab 6.5 procedure. The results showed that the algorithm achieved an average accuracy of 96% for normal seeds, 92% for seeds with fine fissure and 87% for seeds with incompletely closed glumes. The algorithm was proved to be applicable to different seed varieties and insensitive to the color of the background.

  3. A Vision-based Wireless Charging System for Robot Trophallaxis

    Directory of Open Access Journals (Sweden)

    Jae-O Kim

    2015-12-01

    Full Text Available The need to recharge the batteries of a mobile robot has presented an important challenge for a long time. In this paper, a vision-based wireless charging method for robot energy trophallaxis between two robots is presented. Even though wireless power transmission allows more positional error between receiver-transmitter coils than with a contact-type charging system, both coils have to be aligned as accurately as possible for efficient power transfer. To align the coils, a transmitter robot recognizes the coarse pose of a receiver robot via a camera image and the ambiguity of the estimated pose is removed with a Bayesian estimator. The precise pose of the receiver coil is calculated using a marker image attached to a receiver robot. Experiments with several types of receiver robots have been conducted to verify the proposed method.

  4. A shape representation for computer vision based on differential topology.

    Science.gov (United States)

    Blicher, A P

    1995-01-01

    We describe a shape representation for use in computer vision, after a brief review of shape representation and object recognition in general. Our shape representation is based on graph structures derived from level sets whose characteristics are understood from differential topology, particularly singularity theory. This leads to a representation which is both stable and whose changes under deformation are simple. The latter allows smoothing in the representation domain ('symbolic smoothing'), which in turn can be used for coarse-to-fine strategies, or as a discrete analog of scale space. Essentially the same representation applies to an object embedded in 3-dimensional space as to one in the plane, and likewise for a 3D object and its silhouette. We suggest how this can be used for recognition.

  5. Bionic Vision-Based Intelligent Power Line Inspection System.

    Science.gov (United States)

    Li, Qingwu; Ma, Yunpeng; He, Feijia; Xi, Shuya; Xu, Jinxin

    2017-01-01

    Detecting the threats of the external obstacles to the power lines can ensure the stability of the power system. Inspired by the attention mechanism and binocular vision of human visual system, an intelligent power line inspection system is presented in this paper. Human visual attention mechanism in this intelligent inspection system is used to detect and track power lines in image sequences according to the shape information of power lines, and the binocular visual model is used to calculate the 3D coordinate information of obstacles and power lines. In order to improve the real time and accuracy of the system, we propose a new matching strategy based on the traditional SURF algorithm. The experimental results show that the system is able to accurately locate the position of the obstacles around power lines automatically, and the designed power line inspection system is effective in complex backgrounds, and there are no missing detection instances under different conditions.

  6. A Novel Solar Tracker Based on Omnidirectional Computer Vision

    Directory of Open Access Journals (Sweden)

    Zakaria El Kadmiri

    2015-01-01

    Full Text Available This paper presents a novel solar tracker system based on omnidirectional vision technology. The analysis of acquired images with a catadioptric camera allows extracting accurate information about the sun position toward both elevation and azimuth. The main advantages of this system are its wide field of tracking of 360° horizontally and 200° vertically. The system has the ability to track the sun in real time independently of the spatiotemporal coordinates of the site. The extracted information is used to control the two DC motors of the dual-axis mechanism to achieve the optimal orientation of the photovoltaic panels with the aim of increasing the power generation. Several experimental studies have been conducted and the obtained results confirm the power generation efficiency of the proposed solar tracker.

  7. Efficient Learning of VAM-Based Representation of 3D Targets and its Active Vision Applications.

    Science.gov (United States)

    Sharma, Rajeev; Srinivasa, Narayan

    1998-01-01

    There has been a considerable interest in using active vision for various applications. This interest is primarily because active vision can enhance machine vision capabilities by dynamically changing the camera parameters based on the content of the scene. An important issue in active vision is that of representing 3D targets in a manner that is invariant to changing camera configurations. This paper addresses this representation issue for a robotic active vision system. An efficient Vector Associative Map (VAM)-based learning scheme is proposed to learn a joint-based representation. Computer simulations and experiments are first performed to evaluate the effectiveness of this scheme using the University of Illinois Active Vision System (UIAVS). The invariance property of the learned representation is then exploited to develop several robotic applications. These include, detecting moving targets, saccade control, planning saccade sequences and controlling a robot manipulator.

  8. Effect of Vision Therapy on Accommodation in Myopic Chinese Children

    Directory of Open Access Journals (Sweden)

    Martin Ming-Leung Ma

    2016-01-01

    Full Text Available Introduction. We evaluated the effectiveness of office-based accommodative/vergence therapy (OBAVT with home reinforcement to improve accommodative function in myopic children with poor accommodative response. Methods. This was a prospective unmasked pilot study. 14 Chinese myopic children aged 8 to 12 years with at least 1 D of lag of accommodation were enrolled. All subjects received 12 weeks of 60-minute office-based accommodative/vergence therapy (OBAVT with home reinforcement. Primary outcome measure was the change in monocular lag of accommodation from baseline visit to 12-week visit measured by Shinnipon open-field autorefractor. Secondary outcome measures were the changes in accommodative amplitude and monocular accommodative facility. Results. All participants completed the study. The lag of accommodation at baseline visit was 1.29 ± 0.21 D and it was reduced to 0.84 ± 0.19 D at 12-week visit. This difference (−0.46 ± 0.22 D; 95% confidence interval: −0.33 to −0.58 D is statistically significant (p<0.0001. OBAVT also increased the amplitude and facility by 3.66 ± 3.36 D (p=0.0013; 95% confidence interval: 1.72 to 5.60 D and 10.9 ± 4.8 cpm (p<0.0001; 95% confidence interval: 8.1 to 13.6 cpm, respectively. Conclusion. Standardized 12 weeks of OBAVT with home reinforcement is able to significantly reduce monocular lag of accommodation and increase monocular accommodative amplitude and facility. A randomized clinical trial designed to investigate the effect of vision therapy on myopia progression is warranted.

  9. Vision-Based Faint Vibration Extraction Using Singular Value Decomposition

    Directory of Open Access Journals (Sweden)

    Xiujun Lei

    2015-01-01

    Full Text Available Vibration measurement is important for understanding the behavior of engineering structures. Unlike conventional contact-type measurements, vision-based methodologies have attracted a great deal of attention because of the advantages of remote measurement, nonintrusive characteristic, and no mass introduction. It is a new type of displacement sensor which is convenient and reliable. This study introduces the singular value decomposition (SVD methods for video image processing and presents a vibration-extracted algorithm. The algorithms can successfully realize noncontact displacement measurements without undesirable influence to the structure behavior. SVD-based algorithm decomposes a matrix combined with the former frames to obtain a set of orthonormal image bases while the projections of all video frames on the basis describe the vibration information. By means of simulation, the parameters selection of SVD-based algorithm is discussed in detail. To validate the algorithm performance in practice, sinusoidal motion tests are performed. Results indicate that the proposed technique can provide fairly accurate displacement measurement. Moreover, a sound barrier experiment showing how the high-speed rail trains affect the sound barrier nearby is carried out. It is for the first time to be realized at home and abroad due to the challenge of measuring environment.

  10. Vision-based traffic surveys in urban environments

    Science.gov (United States)

    Chen, Zezhi; Ellis, Tim; Velastin, Sergio A.

    2016-09-01

    This paper presents a state-of-the-art, vision-based vehicle detection and type classification to perform traffic surveys from a roadside closed-circuit television camera. Vehicles are detected using background subtraction based on a Gaussian mixture model that can cope with vehicles that become stationary over a significant period of time. Vehicle silhouettes are described using a combination of shape and appearance features using an intensity-based pyramid histogram of orientation gradients (HOG). Classification is performed using a support vector machine, which is trained on a small set of hand-labeled silhouette exemplars. These exemplars are identified using a model-based preclassifier that utilizes calibrated images mapped by Google Earth to provide accurately surveyed scene geometry matched to visible image landmarks. Kalman filters track the vehicles to enable classification by majority voting over several consecutive frames. The system counts vehicles and separates them into four categories: car, van, bus, and motorcycle (including bicycles). Experiments with real-world data have been undertaken to evaluate system performance and vehicle detection rates of 96.45% and classification accuracy of 95.70% have been achieved on this data.

  11. Vision-based control in driving assistance of agricultural vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Khadraoui, D.; Martinet, P.; Bonton, P.; Gallice, J. [Univ. Blaise Pascal, Aubiere (France). Lab. des Sciences et Materiaux pour l`Electronique et d`Automatique; Debain, C. [Inst. de Recherche pour l`Ingenierie de l`Agriculture et de l`Environment, Montoldre (France). Div. Techniques du Machinisme Agricole; Rouveure, R. [Inst. de Recherche pour l`Ingenierie de l`Agriculture et de l`Environment, Antony (France). Div. Electronique et Intelligence Artificielle

    1998-10-01

    This article presents a real-time control system for an agricultural mobile machine (vehicle) based on an on-board vision system using a single camera. This system has been designed to help humans in repetitive and difficult tasks in the agricultural domain. The aim of the robotics application concerns the control of the vehicle with regard to the reap limit detected in image space. The perception aspect in relation to the application has been described in previous work, and here the authors deal with the control aspect. They integrate image features issues from the modeling of the scene in the control loop to perform an image-based servoing technique. The vehicle behavior described here concerns bicycle and neural models, and three control laws are then synthesized. The first and the second are modeling approaches and use an interaction between the scene and the image space. They are based on the regulation of a task function. The third is a black-box modeling technique, and is based on a neural network. Finally, experimental results obtained with these different control laws in different conditions are presented and discussed.

  12. Proceedings of the First International Workshop on Generative-Model-Based Vision

    DEFF Research Database (Denmark)

    In the last decade, there has been a convergence of statistical and model-based approaches to computational vision. This is an ongoing process, leading to the emerging paradigm of generative-model-based (GMB) vision. This workshop/special issue aims to bring together researchers working on differ...

  13. Proceedinsg of the Second International workshop on Generative-Model Based Vision

    DEFF Research Database (Denmark)

    In the last decade, there has been a convergence of statistical and model-based approaches to computational vision. This is an ongoing process, leading to the emerging paradigm of generative-model-based (GMB) vision. This workshop/special issue aims to bring together researchers working on differ...

  14. CT Image Sequence Analysis for Object Recognition - A Rule-Based 3-D Computer Vision System

    Science.gov (United States)

    Dongping Zhu; Richard W. Conners; Daniel L. Schmoldt; Philip A. Araman

    1991-01-01

    Research is now underway to create a vision system for hardwood log inspection using a knowledge-based approach. In this paper, we present a rule-based, 3-D vision system for locating and identifying wood defects using topological, geometric, and statistical attributes. A number of different features can be derived from the 3-D input scenes. These features and evidence...

  15. Visual Behaviour Based Bio-Inspired Polarization Techniques in Computer Vision and Robotics

    OpenAIRE

    Shabayek, Abd El Rahman; Morel, Olivier; Fofi, David

    2012-01-01

    For long time, it was thought that the sensing of polarization by animals is invariably related to their behavior, such as navigation and orientation. Recently, it was found that polarization can be part of a high-level visual perception, permitting a wide area of vision applications. Polarization vision can be used for most tasks of color vision including object recognition, contrast enhancement, camouflage breaking, and signal detection and discrimination. The polarization based visual beha...

  16. Research progress of depth detection in vision measurement: a novel project of bifocal imaging system for 3D measurement

    Science.gov (United States)

    Li, Anhu; Ding, Ye; Wang, Wei; Zhu, Yongjian; Li, Zhizhong

    2013-09-01

    The paper reviews the recent research progresses of vision measurement. The general methods of the depth detection used in the monocular stereo vision are compared with each other. As a result, a novel bifocal imaging measurement system based on the zoom method is proposed to solve the problem of the online 3D measurement. This system consists of a primary lens and a secondary one with the different focal length matching to meet the large-range and high-resolution imaging requirements without time delay and imaging errors, which has an important significance for the industry application.

  17. 3-D measuring of engine camshaft based on machine vision

    Science.gov (United States)

    Qiu, Jianxin; Tan, Liang; Xu, Xiaodong

    2008-12-01

    The non-touch 3D measuring based on machine vision is introduced into camshaft precise measuring. Currently, because CCD 3-dimensional measuring can't meet requirements for camshaft's measuring precision, it's necessary to improve its measuring precision. In this paper, we put forward a method to improve the measuring method. A Multi-Character Match method based on the Polygonal Non-regular model is advanced with the theory of Corner Extraction and Corner Matching .This method has solved the problem of the matching difficulty and a low precision. In the measuring process, the use of the Coded marked Point method and Self-Character Match method can bring on this problem. The 3D measuring experiment on camshaft, which based on the Multi-Character Match method of the Polygonal Non-regular model, proves that the normal average measuring precision is increased to a new level less than 0.04mm in the point-clouds photo merge. This measuring method can effectively increase the 3D measuring precision of the binocular CCD.

  18. Fast vision-based catheter 3D reconstruction

    Science.gov (United States)

    Moradi Dalvand, Mohsen; Nahavandi, Saeid; Howe, Robert D.

    2016-07-01

    Continuum robots offer better maneuverability and inherent compliance and are well-suited for surgical applications as catheters, where gentle interaction with the environment is desired. However, sensing their shape and tip position is a challenge as traditional sensors can not be employed in the way they are in rigid robotic manipulators. In this paper, a high speed vision-based shape sensing algorithm for real-time 3D reconstruction of continuum robots based on the views of two arbitrary positioned cameras is presented. The algorithm is based on the closed-form analytical solution of the reconstruction of quadratic curves in 3D space from two arbitrary perspective projections. High-speed image processing algorithms are developed for the segmentation and feature extraction from the images. The proposed algorithms are experimentally validated for accuracy by measuring the tip position, length and bending and orientation angles for known circular and elliptical catheter shaped tubes. Sensitivity analysis is also carried out to evaluate the robustness of the algorithm. Experimental results demonstrate good accuracy (maximum errors of  ±0.6 mm and  ±0.5 deg), performance (200 Hz), and robustness (maximum absolute error of 1.74 mm, 3.64 deg for the added noises) of the proposed high speed algorithms.

  19. Binocular stereo vision system based on phase matching

    Science.gov (United States)

    Liu, Huixian; Huang, Shujun; Gao, Nan; Zhang, Zonghua

    2016-11-01

    Binocular stereo vision is an efficient way for three dimensional (3D) profile measurement and has broad applications. Image acquisition, camera calibration, stereo matching, and 3D reconstruction are four main steps. Among them, stereo matching is the most important step that has a significant impact on the final result. In this paper, a new stereo matching technique is proposed to combine the absolute fringe order and the unwrapped phase of every pixel. Different from traditional phase matching method, sinusoidal fringe in two perpendicular directions are projected. It can be realized through the following three steps. Firstly, colored sinusoidal fringe in both horizontal (red fringe) and vertical (blue fringe) are projected on the object to be measured, and captured by two cameras synchronously. The absolute fringe order and the unwrapped phase of each pixel along the two directions are calculated based on the optimum three-fringe numbers selection method. Then, based on the absolute fringe order of the left and right phase maps, stereo matching method is presented. In this process, the same absolute fringe orders in both horizontal and vertical directions are searched to find the corresponding point. Based on this technique, as many as possible pairs of homologous points between two cameras are found to improve the precision of the measurement result. Finally, a 3D measuring system is set up and the 3D reconstruction results are shown. The experimental results show that the proposed method can meet the requirements of high precision for industrial measurements.

  20. Recovering stereo vision by squashing virtual bugs in a virtual reality environment.

    Science.gov (United States)

    Vedamurthy, Indu; Knill, David C; Huang, Samuel J; Yung, Amanda; Ding, Jian; Kwon, Oh-Sang; Bavelier, Daphne; Levi, Dennis M

    2016-06-19

    Stereopsis is the rich impression of three-dimensionality, based on binocular disparity-the differences between the two retinal images of the same world. However, a substantial proportion of the population is stereo-deficient, and relies mostly on monocular cues to judge the relative depth or distance of objects in the environment. Here we trained adults who were stereo blind or stereo-deficient owing to strabismus and/or amblyopia in a natural visuomotor task-a 'bug squashing' game-in a virtual reality environment. The subjects' task was to squash a virtual dichoptic bug on a slanted surface, by hitting it with a physical cylinder they held in their hand. The perceived surface slant was determined by monocular texture and stereoscopic cues, with these cues being either consistent or in conflict, allowing us to track the relative weighting of monocular versus stereoscopic cues as training in the task progressed. Following training most participants showed greater reliance on stereoscopic cues, reduced suppression and improved stereoacuity. Importantly, the training-induced changes in relative stereo weights were significant predictors of the improvements in stereoacuity. We conclude that some adults deprived of normal binocular vision and insensitive to the disparity information can, with appropriate experience, recover access to more reliable stereoscopic information.This article is part of the themed issue 'Vision in our three-dimensional world'.

  1. A computer vision based candidate for functional balance test.

    Science.gov (United States)

    Nalci, Alican; Khodamoradi, Alireza; Balkan, Ozgur; Nahab, Fatta; Garudadri, Harinath

    2015-08-01

    Balance in humans is a motor skill based on complex multimodal sensing, processing and control. Ability to maintain balance in activities of daily living (ADL) is compromised due to aging, diseases, injuries and environmental factors. Center for Disease Control and Prevention (CDC) estimate of the costs of falls among older adults was $34 billion in 2013 and is expected to reach $54.9 billion in 2020. In this paper, we present a brief review of balance impairments followed by subjective and objective tools currently used in clinical settings for human balance assessment. We propose a novel computer vision (CV) based approach as a candidate for functional balance test. The test will take less than a minute to administer and expected to be objective, repeatable and highly discriminative in quantifying ability to maintain posture and balance. We present an informal study with preliminary data from 10 healthy volunteers, and compare performance with a balance assessment system called BTrackS Balance Assessment Board. Our results show high degree of correlation with BTrackS. The proposed system promises to be a good candidate for objective functional balance tests and warrants further investigations to assess validity in clinical settings, including acute care, long term care and assisted living care facilities. Our long term goals include non-intrusive approaches to assess balance competence during ADL in independent living environments.

  2. Design Fabrication & Real Time Vision Based Control of Gaming Board

    Directory of Open Access Journals (Sweden)

    Muhammad Nauman Mubarak

    2012-01-01

    Full Text Available This paper presents design, fabrication and real time vision based control of a two degree of freedom (d.o.f robot capable of playing a carom board game. The system consists of three main components: (a a high resolution digital camera (b a main processing and controlling unit (c a robot with two servo motors and striking mechanism. The camera captures the image of arena and transmits it to central processing unit. CPU processes the image and congregate useful information using adaptive histogram technique. Congregated information about the coordinates of the object is then sent to the RISC architecture based microcontroller by serial interface. Microcontroller implements inverse kinematics algorithms and PID control on motors with feedback from high resolution quadrature encoders to reach at the desired coordinates and angles. The striking unit exerts a controlled force on the striker when it is in-line with the disk and carom hole (or, pocket. The striker strikes with the disk and pots (to hit (a ball into a pocket it in the pocket. The objective is to develop an intelligent, cost effective and user friendly system that fulfil the idea of technology for entertainment.

  3. Computer Vision-Based Portable System for Nitroaromatics Discrimination

    Directory of Open Access Journals (Sweden)

    Nuria López-Ruiz

    2016-01-01

    Full Text Available A computer vision-based portable measurement system is presented in this report. The system is based on a compact reader unit composed of a microcamera and a Raspberry Pi board as control unit. This reader can acquire and process images of a sensor array formed by four nonselective sensing chemistries. Processing these array images it is possible to identify and quantify eight different nitroaromatic compounds (both explosives and related compounds by using chromatic coordinates of a color space. The system is also capable of sending the obtained information after the processing by a WiFi link to a smartphone in order to present the analysis result to the final user. The identification and quantification algorithm programmed in the Raspberry board is easy and quick enough to allow real time analysis. Nitroaromatic compounds analyzed in the range of mg/L were picric acid, 2,4-dinitrotoluene (2,4-DNT, 1,3-dinitrobenzene (1,3-DNB, 3,5-dinitrobenzonitrile (3,5-DNBN, 2-chloro-3,5-dinitrobenzotrifluoride (2-C-3,5-DNBF, 1,3,5-trinitrobenzene (TNB, 2,4,6-trinitrotoluene (TNT, and tetryl (TT.

  4. VIP - A Framework-Based Approach to Robot Vision

    Directory of Open Access Journals (Sweden)

    Gerd Mayer

    2008-11-01

    Full Text Available For robot perception, video cameras are very valuable sensors, but the computer vision methods applied to extract information from camera images are usually computationally expensive. Integrating computer vision methods into a robot control architecture requires to balance exploitation of camera images with the need to preserve reactivity and robustness. We claim that better software support is needed in order to facilitate and simplify the application of computer vision and image processing methods on autonomous mobile robots. In particular, such support must address a simplified specification of image processing architectures, control and synchronization issues of image processing steps, and the integration of the image processing machinery into the overall robot control architecture. This paper introduces the video image processing (VIP framework, a software framework for multithreaded control flow modeling in robot vision.

  5. Vision-based coaching: Optimizing resources for leader development

    OpenAIRE

    Passarelli, Angela M.

    2015-01-01

    Leaders develop in the direction of their dreams, not in the direction of their deficits. Yet many coaching interactions intended to promote a leader’s development fail to leverage the developmental benefits of the individual’s personal vision. Drawing on Intentional Change Theory, this article postulates that coaching interactions that emphasize a leader’s personal vision (future aspirations and core identity) evoke a psychophysiological state characterized by positive emotions, cognitive op...

  6. Vision-based coaching: optimizing resources for leader development

    OpenAIRE

    Passarelli, Angela M.

    2015-01-01

    Leaders develop in the direction of their dreams, not in the direction of their deficits. Yet many coaching interactions intended to promote a leader’s development fail to leverage the benefits of the individual’s personal vision. Drawing on intentional change theory, this article postulates that coaching interactions that emphasize a leader’s personal vision (future aspirations and core identity) evoke a psychophysiological state characterized by positive emotions, cognitive openness, and op...

  7. Vision-aided Navigation for Autonomous Aircraft Based on Unscented Kalman Filter

    Directory of Open Access Journals (Sweden)

    Junwei Yu

    2013-02-01

    Full Text Available A vision-aided navigation system for autonomous aircraft is described in this paper. The vision navigation of the aircraft to the known scence is performed with a camera fixed on the aircraft. The location and pose of the aircraft are estimated with the corresponding control points which can be detected in the images captured. The control points are selected according their saliency and are tracked in sequential images based on Fourier-Melline transform. The simulation model of the aircraft dynamics and vision-aided navigation system based on Matlab/Simulink is built.The unscented Kalman filter is used to fuse the aircraft state information provided by the vision system and the inertial navigation system. Simulation results show that the vision-based navigation system provides satisfactory results of both accuracy and reliability.

  8. Rapid license plate location algorithm based on monocular vision%基于单目视觉的车牌快速定位方法

    Institute of Scientific and Technical Information of China (English)

    杨先勇; 王会岩; 周晓莉; 刘东基; 宋盼盼

    2012-01-01

    This paper presents a combination of theory and morphology of the color space. Firstly, image color space is conversed, and the required features of the color region detection to is extracted, Then, the color characteristics of the regional are tested, the gray level statistics on the edge is done, and is filtered by a certain percentage. By using characteristics of the changes of the vehicle location on the front, the coarse positioning of the possible license plate region for the next time is finished, which is benefit of a more rapid positioning for the next time. 100 license plate image are used, for positioning in this which is benefit of algorithm, the positioning accuracy rate is 90%, the speed is in 0.1 s.%提出了一种基于颜色空间理论和形态学结合的方法。首先对图像进行颜色空间转换,按要求提取出需要的特征颜色区域,再对颜色特征区域进行检测,对边缘进行灰度统计,按一定的比例进行筛选,并利用前方车辆位置变化的特点,对下一次车牌可能出现的区域进行粗定位,利于下一次更快速的定位。应用该算法对100幅车牌图像进行定位,定位准确率达90%,速度均在0.1s内。

  9. 基于opencv的单目视觉测量系统的研究%Research on Monocular Vision Measurement System Based on OpenCV

    Institute of Scientific and Technical Information of China (English)

    马晓东; 蒋明; 柯善浩; 曾晓雁; 胡乾午

    2015-01-01

    介绍一种基于机器视觉的测量工件宽度的新方法,在开源计算机视觉库OpenCV的支持下,设计并实现一种对工件宽度进行动态实时测量的系统;为了降低其它光的影响,在CCD镜头下面固定一块红光滤光片,系统通过采集经红光线激光器投射的工件图像,对图像进行二值化、截取感兴趣区域、轮廓提取等处理,最后实现工件宽度的自动测量;对不同尺寸的工件进行了自动测量实验,实验结果表明,采用的测量方法在实际工件测量中是可用的,整个测量过程用时在100 ms左右,最大相对误差不超过1.5%.

  10. Monocular trajectory intersection method for 3D motion measurement of a point target

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This article proposes a monocular trajectory intersection method,a videometrics measurement with a mature theoretical system to solve the 3D motion parameters of a point target.It determines the target’s motion parameters including its 3D trajectory and velocity by intersecting the parametric trajectory of a motion target and series of sight-rays by which a motion camera observes the target,in contrast with the regular intersection method for 3D measurement by which the sight-rays intersect at one point.The method offers an approach to overcome the technical failure of traditional monocular measurements for the 3D motion of a point target and thus extends the application fields of photogrammetry and computer vision.Wide application is expected in passive observations of motion targets on various mobile beds.

  11. Monocular trajectory intersection method for 3D motion measurement of a point target

    Institute of Scientific and Technical Information of China (English)

    YU QiFeng; SHANG Yang; ZHOU Jian; ZHANG XiaoHu; LI LiChun

    2009-01-01

    This article proposes a monocular trajectory intersection method,a videometrics measurement with a mature theoretical system to solve the 3D motion parameters of a point target.It determines the target's motion parameters including its 3D trajectory and velocity by intersecting the parametric trajectory of a motion target and series of sight-rays by which a motion camera observes the target,in contrast with the regular intersection method for 3D measurement by which the sight-rays intersect at one point.The method offers an approach to overcome the technical failure of traditional monocular measurements for the 3D motion of a point target and thus extends the application fields of photogrammetry and computer vision.Wide application is expected in passive observations of motion targets on various mobile beds.

  12. Environmentally Conscious Polishing System Based on Robotics and Artificial Vision

    Directory of Open Access Journals (Sweden)

    J. A. Dieste

    2015-02-01

    Full Text Available Polishing process is one of the manufacturing issues that are essential in the production flow, but it generates the major amount of defects on parts. Finishing tasks in which polishing is included are performed in the final steps of the manufacturing sequence. Any defect in these steps impliesrejection of the part, generating a big amount of scrap and generating a huge amount of energy consumption, emission, and time to manufacture and replace the rejected part. Traditionally polishing process has not evolved during the last 30 years, while other manufacturing processes have been automated and technologically improved. Finishing processes (grinding and polishing, are still manually performed, especially in freeform surface parts, but to be sustainable some development and automation have to be introduced. This research proposes a novel polishing system based on robotics and artificial vision. The application of this novel system has allowed reducing the failed parts due to finishing process down to zero percent from 28% of rejected parts with manual polishing process. The reduction in process time consumption, and amount of scrapped parts, has reduced the energy consumption up to 30% in finishing process and 20% in whole manufacturing process for an injection moulded aluminium part for automotive industry with high production volumes.

  13. Vision-Based Georeferencing of GPR in Urban Areas

    Directory of Open Access Journals (Sweden)

    Riccardo Barzaghi

    2016-01-01

    Full Text Available Ground Penetrating Radar (GPR surveying is widely used to gather accurate knowledge about the geometry and position of underground utilities. The sensor arrays need to be coupled to an accurate positioning system, like a geodetic-grade Global Navigation Satellite System (GNSS device. However, in urban areas this approach is not always feasible because GNSS accuracy can be substantially degraded due to the presence of buildings, trees, tunnels, etc. In this work, a photogrammetric (vision-based method for GPR georeferencing is presented. The method can be summarized in three main steps: tie point extraction from the images acquired during the survey, computation of approximate camera extrinsic parameters and finally a refinement of the parameter estimation using a rigorous implementation of the collinearity equations. A test under operational conditions is described, where accuracy of a few centimeters has been achieved. The results demonstrate that the solution was robust enough for recovering vehicle trajectories even in critical situations, such as poorly textured framed surfaces, short baselines, and low intersection angles.

  14. Prolog-based prototyping software for machine vision

    Science.gov (United States)

    Batchelor, Bruce G.; Hack, Ralf; Jones, Andrew C.

    1996-10-01

    Prolog image processing (PIP) is a multi-media prototyping tool, intended to assist designers of intelligent industrial machine vision systems. This is the latest in a series of prolog-based systems that have been implemented at Cardiff, specifically for this purpose. The software package provides fully integrated facilities for both interactive and programmed image processing, 'smart' documentation, guidance about which lighting/viewing set-up to use, speech/natural language input and speech output. It can also be used to control a range of electro-mechanical devices, such as lamps, cameras, lenses, pneumatic positioning mechanisms, robots, etc., via a low-cost hardware interfacing module. The software runs on a standard computer, with no predecessors in that the image processing is carried out entirely in software. This article concentrates on the design and implementation of the PIP system, and presents programs for two demonstration applications: (a) recognizing a non-picture playing card; (b) recognizing a well laid table place setting.

  15. Research on Manufacturing Technology Based on Machine Vision

    Institute of Scientific and Technical Information of China (English)

    HU Zhanqi; ZHENG Kuijing

    2006-01-01

    The concept of machine vision based manufacturing technology is proposed first, and the key algorithms used in two-dimensional and three-dimensional machining are discussed in detail. Machining information can be derived from the binary images and gray picture after processing and transforming the picture. Contour and the parallel cutting method about two-dimensional machining are proposed. Polygon approximating algorithm is used to cutting the profile of the workpiece. Fill Scanning algorithm used to machining inner part of a pocket. The improved Shape From Shading method with adaptive pre-processing is adopted to reconstruct the three-dimensional model. Layer cutting method is adopted for three-dimensional machining. The tool path is then gotten from the model, and NC code is formed subsequently. The model can be machined conveniently by the lathe, milling machine or engraver. Some examples are given to demonstrate the results of ImageCAM system, which is developed by the author to implement the algorithms previously mentioned.

  16. Vision Based Obstacle Detection mechanism of a Fixed Wing UAV

    Directory of Open Access Journals (Sweden)

    S.N. Omkar

    2014-03-01

    Full Text Available In this paper we have developed a vision based navigation and obstacle detection mechanism for unmanned aerial vehicles (UAVs which can be used effectively in GPS denied regions as well as in regions where remote controlled UAV navigation is impossible thus making the UAV more versatile and fully autonomous. We used a fixed single onboard video camera on the UAV that extracts images of the environment of a UAV. These images are then processed and detect an obstacle in the path if any. This method is effective in detecting dark as well as light coloured obstacles in the vicinity of the UAV. We developed two algorithms. The first one is to detect the horizon and land in the images extracted from the camera and to detect an obstacle in its path. The second one is specifically to detect a light coloured obstacle in the environment thus making our method more precise. The time taken for processing of the images and generating a result is very small thus this algorithm is also fit to be used in real time applications. These Algorithms are more effective than previously developed in this field because this algorithm does the detection of any obstacle without knowing the size of it beforehand. This algorithm is also capable of detecting light coloured obstacles in the sky which otherwise might be missed by an UAV or even a human pilot sometimes. Thus it makes the navigation more precise.

  17. KNOWLEDGE-BASED ROBOT VISION SYSTEM FOR AUTOMATED PART HANDLING

    Directory of Open Access Journals (Sweden)

    J. Wang

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: This paper discusses an algorithm incorporating a knowledge-based vision system into an industrial robot system for handling parts intelligently. A continuous fuzzy controller was employed to extract boundary information in a computationally efficient way. The developed algorithm for on-line part recognition using fuzzy logic is shown to be an effective solution to extract the geometric features of objects. The proposed edge vector representation method provides enough geometric information and facilitates the object geometric reconstruction for gripping planning. Furthermore, a part-handling model was created by extracting the grasp features from the geometric features.

    AFRIKAANSE OPSOMMING: Hierdie artikel beskryf ‘n kennis-gebaseerde visiesisteemalgoritme wat in ’n industriёle robotsisteem ingesluit word om sodoende intelligente komponenthantering te bewerkstellig. ’n Kontinue wasige beheerder is gebruik om allerlei objekinligting deur middel van ’n effektiewe berekeningsmetode te bepaal. Die ontwikkelde algoritme vir aan-lyn komponentherkenning maak gebruik van wasige logika en word bewys as ’n effektiewe metode om geometriese inligting van objekte te bepaal. Die voorgestelde grensvektormetode verskaf voldoende inligting en maak geometriese rekonstruksie van die objek moontlik om greepbeplanning te kan doen. Voorts is ’n komponenthanteringsmodel ontwikkel deur die grypkenmerke af te lei uit die geometriese eienskappe.

  18. A vision-based method for planar position measurement

    Science.gov (United States)

    Chen, Zong-Hao; Huang, Peisen S.

    2016-12-01

    In this paper, a vision-based method is proposed for three-degree-of-freedom (3-DOF) planar position (XY{θZ} ) measurement. This method uses a single camera to capture the image of a 2D periodic pattern and then uses the 2D discrete Fourier transform (2D DFT) method to estimate the phase of its fundamental frequency component for position measurement. To improve position measurement accuracy, the phase estimation error of 2D DFT is analyzed and a phase estimation method is proposed. Different simulations are done to verify the feasibility of this method and study the factors that influence the accuracy and precision of phase estimation. To demonstrate the performance of the proposed method for position measurement, a prototype encoder consisting of a black-and-white industrial camera with VGA resolution (480  ×  640 pixels) and an iPhone 4s has been developed. Experimental results show the peak-to-peak resolutions to be 3.5 nm in X axis, 8 nm in Y axis and 4 μ \\text{rad} in {θZ} axis. The corresponding RMS resolutions are 0.52 nm, 1.06 nm, and 0.60 μ \\text{rad} respectively.

  19. Vision-Based Georeferencing of GPR in Urban Areas

    Science.gov (United States)

    Barzaghi, Riccardo; Cazzaniga, Noemi Emanuela; Pagliari, Diana; Pinto, Livio

    2016-01-01

    Ground Penetrating Radar (GPR) surveying is widely used to gather accurate knowledge about the geometry and position of underground utilities. The sensor arrays need to be coupled to an accurate positioning system, like a geodetic-grade Global Navigation Satellite System (GNSS) device. However, in urban areas this approach is not always feasible because GNSS accuracy can be substantially degraded due to the presence of buildings, trees, tunnels, etc. In this work, a photogrammetric (vision-based) method for GPR georeferencing is presented. The method can be summarized in three main steps: tie point extraction from the images acquired during the survey, computation of approximate camera extrinsic parameters and finally a refinement of the parameter estimation using a rigorous implementation of the collinearity equations. A test under operational conditions is described, where accuracy of a few centimeters has been achieved. The results demonstrate that the solution was robust enough for recovering vehicle trajectories even in critical situations, such as poorly textured framed surfaces, short baselines, and low intersection angles. PMID:26805842

  20. Insect vision based collision avoidance system for Remotely Piloted Aircraft

    Science.gov (United States)

    Jaenisch, Holger; Handley, James; Bevilacqua, Andrew

    2012-06-01

    Remotely Piloted Aircraft (RPA) are designed to operate in many of the same areas as manned aircraft; however, the limited instantaneous field of regard (FOR) that RPA pilots have limits their ability to react quickly to nearby objects. This increases the danger of mid-air collisions and limits the ability of RPA's to operate in environments such as terminals or other high-traffic environments. We present an approach based on insect vision that increases awareness while keeping size, weight, and power consumption at a minimum. Insect eyes are not designed to gather the same level of information that human eyes do. We present a novel Data Model and dynamically updated look-up-table approach to interpret non-imaging direction sensing only detectors observing a higher resolution video image of the aerial field of regard. Our technique is a composite hybrid method combining a small cluster of low resolution cameras multiplexed into a single composite air picture which is re-imaged by an insect eye to provide real-time scene understanding and collision avoidance cues. We provide smart camera application examples from parachute deployment testing and micro unmanned aerial vehicle (UAV) full motion video (FMV).

  1. Does monocular visual space contain planes?

    NARCIS (Netherlands)

    Koenderink, J.J.; Albertazzi, L.; Doorn, A.J. van; Ee, R. van; Grind, W.A. van de; Kappers, A.M.L.; Lappin, J.S.; Norman, J.F.; Oomes, A.H.J.; Pas, S.F. te; Phillips, F.; Pont, S.C.; Richards, W.A.; Todd, J.T.; Verstraten, F.A.J.; Vries, S.C. de

    2010-01-01

    The issue of the existence of planes—understood as the carriers of a nexus of straight lines—in the monocular visual space of a stationary human observer has never been addressed. The most recent empirical data apply to binocular visual space and date from the 1960s (Foley, 1964). This appears to be

  2. A Stereo-Vision Based Hazard-Detection Algorithm for Future Planetary Landers

    Science.gov (United States)

    Woicke, S.; Mooij, E.

    2014-06-01

    A hazard detection algorithm based on the stereo-vision principle is presented. A sensitivity analysis concerning the minimum baseline and the maximum altitude is discussed, based on which the limitations of this algorithm are investigated.

  3. Recovery of neurofilament following early monocular deprivation

    Directory of Open Access Journals (Sweden)

    Timothy P O'Leary

    2012-04-01

    Full Text Available A brief period of monocular deprivation in early postnatal life can alter the structure of neurons within deprived-eye-receiving layers of the dorsal lateral geniculate nucleus. The modification of structure is accompanied by a marked reduction in labeling for neurofilament, a protein that composes the stable cytoskeleton and that supports neuron structure. This study examined the extent of neurofilament recovery in monocularly deprived cats that either had their deprived eye opened (binocular recovery, or had the deprivation reversed to the fellow eye (reverse occlusion. The degree to which recovery was dependent on visually-driven activity was examined by placing monocularly deprived animals in complete darkness (dark rearing. The loss of neurofilament and the reduction of soma size caused by monocular deprivation were both ameliorated equally following either binocular recovery or reverse occlusion for 8 days. Though monocularly deprived animals placed in complete darkness showed recovery of soma size, there was a generalized loss of neurofilament labeling that extended to originally non-deprived layers. Overall, these results indicate that recovery of soma size is achieved by removal of the competitive disadvantage of the deprived eye, and occurred even in the absence of visually-driven activity. Recovery of neurofilament occurred when the competitive disadvantage of the deprived eye was removed, but unlike the recovery of soma size, was dependent upon visually-driven activity. The role of neurofilament in providing stable neural structure raises the intriguing possibility that dark rearing, which reduced overall neurofilament levels, could be used to reset the deprived visual system so as to make it more ameliorable with treatment by experiential manipulations.

  4. Vision-based methodology for collaborative management of qualitative criteria in design

    DEFF Research Database (Denmark)

    Tollestrup, Christian

    2006-01-01

    A Vision-based methodology is proposed as part of the management of qualitative criteria for design in early phases of the product development process for team based organisations. Focusing on abstract values and qualities for the product establishes a shared vision for the product amongst team...... members. Two anchor points are used for representing these values and qualities, the Value Mission and the Interaction Vision. Qualifying the meaning of these words trough triangulation of methods develops a shared mental model within the team. The composition of keywords within the Vision and Mission...... establishes a field of tension that summarises the abstract criteria and pinpoints the desired uniqueness of the product. The Interaction Vision allows the team members to design the behaviour of the product without deciding on physical features, thus focusing on the cognitive aspects of the product...

  5. Deformable Surface 3D Reconstruction from Monocular Images

    CERN Document Server

    Salzmann, Matthieu

    2010-01-01

    Being able to recover the shape of 3D deformable surfaces from a single video stream would make it possible to field reconstruction systems that run on widely available hardware without requiring specialized devices. However, because many different 3D shapes can have virtually the same projection, such monocular shape recovery is inherently ambiguous. In this survey, we will review the two main classes of techniques that have proved most effective so far: The template-based methods that rely on establishing correspondences with a reference image in which the shape is already known, and non-rig

  6. Vision Based Autonomous Robotic Control for Advanced Inspection and Repair

    Science.gov (United States)

    Wehner, Walter S.

    2014-01-01

    The advanced inspection system is an autonomous control and analysis system that improves the inspection and remediation operations for ground and surface systems. It uses optical imaging technology with intelligent computer vision algorithms to analyze physical features of the real-world environment to make decisions and learn from experience. The advanced inspection system plans to control a robotic manipulator arm, an unmanned ground vehicle and cameras remotely, automatically and autonomously. There are many computer vision, image processing and machine learning techniques available as open source for using vision as a sensory feedback in decision-making and autonomous robotic movement. My responsibilities for the advanced inspection system are to create a software architecture that integrates and provides a framework for all the different subsystem components; identify open-source algorithms and techniques; and integrate robot hardware.

  7. CAD-model-based vision for space applications

    Science.gov (United States)

    Shapiro, Linda G.

    1988-01-01

    A pose acquisition system operating in space must be able to perform well in a variety of different applications including automated guidance and inspections tasks with many different, but known objects. Since the space station is being designed with automation in mind, there will be CAD models of all the objects, including the station itself. The construction of vision models and procedures directly from the CAD models is the goal of this project. The system that is being designed and implementing must convert CAD models to vision models, predict visible features from a given view point from the vision models, construct view classes representing views of the objects, and use the view class model thus derived to rapidly determine the pose of the object from single images and/or stereo pairs.

  8. Intelligent Vision System for Door Sensing Mobile Robot

    Directory of Open Access Journals (Sweden)

    Jharna Majumdar

    2012-08-01

    Full Text Available Wheeled Mobile Robots find numerous applications in the Indoor man made structured environments. In order to operate effectively, the robots must be capable of sensing its surroundings. Computer Vision is one of the prime research areas directed towards achieving these sensing capabilities. In this paper, we present a Door Sensing Mobile Robot capable of navigating in the indoor environment. A robust and inexpensive approach for recognition and classification of the door, based on monocular vision system helps the mobile robot in decision making. To prove the efficacy of the algorithm we have designed and developed a ‘Differentially’ Driven Mobile Robot. A wall following behavior using Ultra Sonic range sensors is employed by the mobile robot for navigation in the corridors.  Field Programmable Gate Arrays (FPGA have been used for the implementation of PD Controller for wall following and PID Controller to control the speed of the Geared DC Motor.

  9. Laser Vision-Based Plant Geometries Computation in Greenhouses

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2014-04-01

    Full Text Available Plant growth statuses are important parameters in the greenhouse environment control system. It is time-consumed and less accuracy that measuring the plant geometries manually in greenhouses. To find a portable method to measure the growth parameters of plants portably and automatically, a laser vision-based measurement system was developed in this paper, consisting of a camera and a laser sheet that scanned the plant vertically. All equipments were mounted on a metal shelf in size of 30cm*40cm*100cm. The 3D point cloud was obtained with the laser sheet scanning the plant vertically, while the camera videoing the laser lines which projected on the plant. The calibration was conducted by a two solid boards standing together in an angle of 90. The camera’s internal and external parameters were calibrated by Image toolbox in MatLab®. It is useful to take a reference image without laser light and to use difference images to obtain the laser line. Laser line centers were extracted by improved centroid method. Thus, we obtained the 3D point cloud structure of the sample plant. For leaf length measurement, iteration method for point clouds was used to extract the axis of the leaf point cloud set. Start point was selected at the end of the leaf point cloud set as the first point of the leaf axis. The points in a radian of certain distance around the start point were chosen as the subset. The centroid of the subset of points was calculated and taken as the next axis point. Iteration was continued until all points in the leaf point cloud set were selected. Leaf length was calculated by curve fitting on these axis points. In order to increase the accuracy of curve fitting, bi-directional start point selection was useful. For leaf area estimation, exponential regression model was used to describe the grown leaves for sampled plant (water spinach in this paper. To evaluate the method in a sample of 18 water spinaches, planted in the greenhouse (length 16

  10. Autonomous Vision-Based Tethered-Assisted Rover Docking

    Science.gov (United States)

    Tsai, Dorian; Nesnas, Issa A.D.; Zarzhitsky, Dimitri

    2013-01-01

    Many intriguing science discoveries on planetary surfaces, such as the seasonal flows on crater walls and skylight entrances to lava tubes, are at sites that are currently inaccessible to state-of-the-art rovers. The in situ exploration of such sites is likely to require a tethered platform both for mechanical support and for providing power and communication. Mother/daughter architectures have been investigated where a mother deploys a tethered daughter into extreme terrains. Deploying and retracting a tethered daughter requires undocking and re-docking of the daughter to the mother, with the latter being the challenging part. In this paper, we describe a vision-based tether-assisted algorithm for the autonomous re-docking of a daughter to its mother following an extreme terrain excursion. The algorithm uses fiducials mounted on the mother to improve the reliability and accuracy of estimating the pose of the mother relative to the daughter. The tether that is anchored by the mother helps the docking process and increases the system's tolerance to pose uncertainties by mechanically aligning the mating parts in the final docking phase. A preliminary version of the algorithm was developed and field-tested on the Axel rover in the JPL Mars Yard. The algorithm achieved an 80% success rate in 40 experiments in both firm and loose soils and starting from up to 6 m away at up to 40 deg radial angle and 20 deg relative heading. The algorithm does not rely on an initial estimate of the relative pose. The preliminary results are promising and help retire the risk associated with the autonomous docking process enabling consideration in future martian and lunar missions.

  11. END-TO-END DEPTH FROM MOTION WITH STABILIZED MONOCULAR VIDEOS

    Directory of Open Access Journals (Sweden)

    C. Pinard

    2017-08-01

    Full Text Available We propose a depth map inference system from monocular videos based on a novel dataset for navigation that mimics aerial footage from gimbal stabilized monocular camera in rigid scenes. Unlike most navigation datasets, the lack of rotation implies an easier structure from motion problem which can be leveraged for different kinds of tasks such as depth inference and obstacle avoidance. We also propose an architecture for end-to-end depth inference with a fully convolutional network. Results show that although tied to camera inner parameters, the problem is locally solvable and leads to good quality depth prediction.

  12. Vision screening for children 36 to practices.

    Science.gov (United States)

    Cotter, Susan A; Cyert, Lynn A; Miller, Joseph M; Quinn, Graham E

    2015-01-01

    This article provides recommendations for screening children aged 36 to younger than 72 months for eye and visual system disorders. The recommendations were developed by the National Expert Panel to the National Center for Children's Vision and Eye Health, sponsored by Prevent Blindness, and funded by the Maternal and Child Health Bureau of the Health Resources and Services Administration, United States Department of Health and Human Services. The recommendations describe both best and acceptable practice standards. Targeted vision disorders for screening are primarily amblyopia, strabismus, significant refractive error, and associated risk factors. The recommended screening tests are intended for use by lay screeners, nurses, and other personnel who screen children in educational, community, public health, or primary health care settings. Characteristics of children who should be examined by an optometrist or ophthalmologist rather than undergo vision screening are also described. There are two current best practice vision screening methods for children aged 36 to younger than 72 months: (1) monocular visual acuity testing using single HOTV letters or LEA Symbols surrounded by crowding bars at a 5-ft (1.5 m) test distance, with the child responding by either matching or naming, or (2) instrument-based testing using the Retinomax autorefractor or the SureSight Vision Screener with the Vision in Preschoolers Study data software installed (version 2.24 or 2.25 set to minus cylinder form). Using the Plusoptix Photoscreener is acceptable practice, as is adding stereoacuity testing using the PASS (Preschool Assessment of Stereopsis with a Smile) stereotest as a supplemental procedure to visual acuity testing or autorefraction. The National Expert Panel recommends that children aged 36 to younger than 72 months be screened annually (best practice) or at least once (accepted minimum standard) using one of the best practice approaches. Technological updates will be

  13. Monocular and binocular depth discrimination thresholds.

    Science.gov (United States)

    Kaye, S B; Siddiqui, A; Ward, A; Noonan, C; Fisher, A C; Green, J R; Brown, M C; Wareing, P A; Watt, P

    1999-11-01

    Measurement of stereoacuity at varying distances, by real or simulated depth stereoacuity tests, is helpful in the evaluation of patients with binocular imbalance or strabismus. Although the cue of binocular disparity underpins stereoacuity tests, there may be variable amounts of other binocular and monocular cues inherent in a stereoacuity test. In such circumstances, a combined monocular and binocular threshold of depth discrimination may be measured--stereoacuity conventionally referring to the situation where binocular disparity giving rise to retinal disparity is the only cue present. A child-friendly variable distance stereoacuity test (VDS) was developed, with a method for determining the binocular depth threshold from the combined monocular and binocular threshold of depth of discrimination (CT). Subjects with normal binocular function, reduced binocular function, and apparently absent binocularity were included. To measure the threshold of depth discrimination, subjects were required by means of a hand control to align two electronically controlled spheres at viewing distances of 1, 3, and 6m. Stereoacuity was also measured using the TNO, Frisby, and Titmus stereoacuity tests. BTs were calculated according to the function BT= arctan (1/tan alphaC - 1/tan alphaM)(-1), where alphaC and alphaM are the angles subtended at the nodal points by objects situated at the monocular threshold (alphaM) and the combined monocular-binocular threshold (alphaC) of discrimination. In subjects with good binocularity, BTs were similar to their combined thresholds, whereas subjects with reduced and apparently absent binocularity had binocular thresholds 4 and 10 times higher than their combined thresholds (CT). The VDS binocular thresholds showed significantly higher correlation and agreement with the TNO test and the binocular thresholds of the Frisby and Titmus tests, than the corresponding combined thresholds (p = 0.0019). The VDS was found to be an easy to use real depth

  14. Night vision devices. Citations from the NTIS data base

    Science.gov (United States)

    Habercom, G. E., Jr.

    1980-08-01

    This bibliography contains 323 citations in which various types of night vision devices are investigated. Most were developed for military applications but they can readily be adapted for civil usage, as for example, law enforcement. Abstracts on display screens, equipment design and effectiveness, electronic components, spurious noise reduction, and test methods are cited.

  15. Zero Accident Vision based strategies in organisations: Innovative perspectives

    NARCIS (Netherlands)

    Zwetsloot, G.I.J.M.; Kines, P.; Wybo, J.L.; Ruotsala, R.; Drupsteen, L.; Bezemer, R.A.

    2017-01-01

    The Zero Accident Vision (ZAV) is a promising approach developed in industry, but not so much addressed by the safety science research community. In a discussion paper in Safety Science (2013) a call was made for more research in this area. Three years later is a good time to take status of developm

  16. Insect-Based Vision for Autonomous Vehicles: A Feasibility Study

    Science.gov (United States)

    Srinivasan, Mandyam V.

    1999-01-01

    The aims of the project were to use a high-speed digital video camera to pursue two questions: (1) To explore the influence of temporal imaging constraints on the performance of vision systems for autonomous mobile robots; (2) To study the fine structure of insect flight trajectories in order to better understand the characteristics of flight control, orientation and navigation.

  17. 3D VISION-BASED DIETARY INSPECTION FOR THE CENTRAL KITCHEN AUTOMATION

    National Research Council Canada - National Science Library

    Yue-Min Jiang; Ho-Hsin Lee; Cheng-Chang Lien; Chun-Feng Tai; PiChun Chu; Ting-Wei Yang

    2014-01-01

    .... In the proposed system, firstly, the meal box can be detected and located automatically with the vision-based method and then all the food ingredients can be identified by using the color and LBP-HF texture features...

  18. Differential processing of binocular and monocular gloss cues in human visual cortex

    Science.gov (United States)

    Di Luca, Massimiliano; Ban, Hiroshi; Muryy, Alexander; Fleming, Roland W.

    2016-01-01

    The visual impression of an object's surface reflectance (“gloss”) relies on a range of visual cues, both monocular and binocular. Whereas previous imaging work has identified processing within ventral visual areas as important for monocular cues, little is known about cortical areas involved in processing binocular cues. Here, we used human functional MRI (fMRI) to test for brain areas selectively involved in the processing of binocular cues. We manipulated stereoscopic information to create four conditions that differed in their disparity structure and in the impression of surface gloss that they evoked. We performed multivoxel pattern analysis to find areas whose fMRI responses allow classes of stimuli to be distinguished based on their depth structure vs. material appearance. We show that higher dorsal areas play a role in processing binocular gloss information, in addition to known ventral areas involved in material processing, with ventral area lateral occipital responding to both object shape and surface material properties. Moreover, we tested for similarities between the representation of gloss from binocular cues and monocular cues. Specifically, we tested for transfer in the decoding performance of an algorithm trained on glossy vs. matte objects defined by either binocular or by monocular cues. We found transfer effects from monocular to binocular cues in dorsal visual area V3B/kinetic occipital (KO), suggesting a shared representation of the two cues in this area. These results indicate the involvement of mid- to high-level visual circuitry in the estimation of surface material properties, with V3B/KO potentially playing a role in integrating monocular and binocular cues. PMID:26912596

  19. Differential processing of binocular and monocular gloss cues in human visual cortex.

    Science.gov (United States)

    Sun, Hua-Chun; Di Luca, Massimiliano; Ban, Hiroshi; Muryy, Alexander; Fleming, Roland W; Welchman, Andrew E

    2016-06-01

    The visual impression of an object's surface reflectance ("gloss") relies on a range of visual cues, both monocular and binocular. Whereas previous imaging work has identified processing within ventral visual areas as important for monocular cues, little is known about cortical areas involved in processing binocular cues. Here, we used human functional MRI (fMRI) to test for brain areas selectively involved in the processing of binocular cues. We manipulated stereoscopic information to create four conditions that differed in their disparity structure and in the impression of surface gloss that they evoked. We performed multivoxel pattern analysis to find areas whose fMRI responses allow classes of stimuli to be distinguished based on their depth structure vs. material appearance. We show that higher dorsal areas play a role in processing binocular gloss information, in addition to known ventral areas involved in material processing, with ventral area lateral occipital responding to both object shape and surface material properties. Moreover, we tested for similarities between the representation of gloss from binocular cues and monocular cues. Specifically, we tested for transfer in the decoding performance of an algorithm trained on glossy vs. matte objects defined by either binocular or by monocular cues. We found transfer effects from monocular to binocular cues in dorsal visual area V3B/kinetic occipital (KO), suggesting a shared representation of the two cues in this area. These results indicate the involvement of mid- to high-level visual circuitry in the estimation of surface material properties, with V3B/KO potentially playing a role in integrating monocular and binocular cues. Copyright © 2016 the American Physiological Society.

  20. Vision-Based Leader/Follower Tracking for Nonholonomic Mobile Robots

    Science.gov (United States)

    2006-01-01

    06/#1 Title: Vision-based Leader/Follower Tracking for Nonholonomic Mobile Robots Authors: Hariprasad Kannan, Vilas. K. Chitrakaran, Darren. M...for Nonholonomic Mobile Robots 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER...298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Vision-Based Leader/Follower Tracking for Nonholonomic Mobile Robots Hariprasad Kannan, Vilas K

  1. Quantitative perceived depth from sequential monocular decamouflage.

    Science.gov (United States)

    Brooks, K R; Gillam, B J

    2006-03-01

    We present a novel binocular stimulus without conventional disparity cues whose presence and depth are revealed by sequential monocular stimulation (delay > or = 80 ms). Vertical white lines were occluded as they passed behind an otherwise camouflaged black rectangular target. The location (and instant) of the occlusion event, decamouflaging the target's edges, differed in the two eyes. Probe settings to match the depth of the black rectangular target showed a monotonic increase with simulated depth. Control tests discounted the possibility of subjects integrating retinal disparities over an extended temporal window or using temporal disparity. Sequential monocular decamouflage was found to be as precise and accurate as conventional simultaneous stereopsis with equivalent depths and exposure durations.

  2. Monocular depth effects on perceptual fading.

    Science.gov (United States)

    Hsu, Li-Chuan; Kramer, Peter; Yeh, Su-Ling

    2010-08-06

    After prolonged viewing, a static target among moving non-targets is perceived to repeatedly disappear and reappear. An uncrossed stereoscopic disparity of the target facilitates this Motion-Induced Blindness (MIB). Here we test whether monocular depth cues can affect MIB too, and whether they can also affect perceptual fading in static displays. Experiment 1 reveals an effect of interposition: more MIB when the target appears partially covered by, than when it appears to cover, its surroundings. Experiment 2 shows that the effect is indeed due to interposition and not to the target's contours. Experiment 3 induces depth with the watercolor illusion and replicates Experiment 1. Experiments 4 and 5 replicate Experiments 1 and 3 without the use of motion. Since almost any stimulus contains a monocular depth cue, we conclude that perceived depth affects perceptual fading in almost any stimulus, whether dynamic or static. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. Monocular discs in the occlusion zones of binocular surfaces do not have quantitative depth--a comparison with Panum's limiting case.

    Science.gov (United States)

    Gillam, Barbara; Cook, Michael; Blackburn, Shane

    2003-01-01

    Da Vinci stereopsis is defined as apparent depth seen in a monocular object laterally adjacent to a binocular surface in a position consistent with its occlusion by the other eye. It is widely regarded as a new form of quantitative stereopsis because the depth seen is quantitatively related to the lateral separation of the monocular element and the binocular surface (Nakayama and Shimojo 1990 Vision Research 30 1811-1825). This can be predicted on the basis that the more separated the monocular element is from the surface the greater its minimum depth behind the surface would have to be to account for its monocular occlusion. Supporting evidence, however, has used narrow bars as the monocular elements, raising the possibility that quantitative depth as a function of separation could be attributable to Panum's limiting case (double fusion) rather than to a new form of stereopsis. We compared the depth performance of monocular objects fusible with the edge of the surface in the contralateral eye (lines) and non-fusible objects (disks) and found that, although the fusible objects showed highly quantitative depth, the disks did not, appearing behind the surface to the same degree at all separations from it. These findings indicate that, although there is a crude sense of depth for discrete monocular objects placed in a valid position for uniocular occlusion, depth is not quantitative. They also indicate that Panum's limiting case is not, as has sometimes been claimed, itself a case of da Vinci stereopsis since fusibility is a critical factor for seeing quantitative depth in discrete monocular objects relative to a binocular surface.

  4. Vision-based navigation in a dynamic environment for virtual human

    Science.gov (United States)

    Liu, Yan; Sun, Ji-Zhou; Zhang, Jia-Wan; Li, Ming-Chu

    2004-06-01

    Intelligent virtual human is widely required in computer games, ergonomics software, virtual environment and so on. We present a vision-based behavior modeling method to realize smart navigation in a dynamic environment. This behavior model can be divided into three modules: vision, global planning and local planning. Vision is the only channel for smart virtual actor to get information from the outside world. Then, the global and local planning module use A* and D* algorithm to find a way for virtual human in a dynamic environment. Finally, the experiments on our test platform (Smart Human System) verify the feasibility of this behavior model.

  5. Monocular alignment in different depth planes.

    Science.gov (United States)

    Shimono, Koichi; Wade, Nicholas J

    2002-04-01

    We examined (a) whether vertical lines at different physical horizontal positions in the same eye can appear to be aligned, and (b), if so, whether the difference between the horizontal positions of the aligned vertical lines can vary with the perceived depth between them. In two experiments, each of two vertical monocular lines was presented (in its respective rectangular area) in one field of a random-dot stereopair with binocular disparity. In Experiment 1, 15 observers were asked to align a line in an upper area with a line in a lower area. The results indicated that when the lines appeared aligned, their horizontal physical positions could differ and the direction of the difference coincided with the type of disparity of the rectangular areas; this is not consistent with the law of the visual direction of monocular stimuli. In Experiment 2, 11 observers were asked to report relative depth between the two lines and to align them. The results indicated that the difference of the horizontal position did not covary with their perceived relative depth, suggesting that the visual direction and perceived depth of the monocular line are mediated via different mechanisms.

  6. Visual SLAM for Handheld Monocular Endoscope.

    Science.gov (United States)

    Grasa, Óscar G; Bernal, Ernesto; Casado, Santiago; Gil, Ismael; Montiel, J M M

    2014-01-01

    Simultaneous localization and mapping (SLAM) methods provide real-time estimation of 3-D models from the sole input of a handheld camera, routinely in mobile robotics scenarios. Medical endoscopic sequences mimic a robotic scenario in which a handheld camera (monocular endoscope) moves along an unknown trajectory while observing an unknown cavity. However, the feasibility and accuracy of SLAM methods have not been extensively validated with human in vivo image sequences. In this work, we propose a monocular visual SLAM algorithm tailored to deal with medical image sequences in order to provide an up-to-scale 3-D map of the observed cavity and the endoscope trajectory at frame rate. The algorithm is validated over synthetic data and human in vivo sequences corresponding to 15 laparoscopic hernioplasties where accurate ground-truth distances are available. It can be concluded that the proposed procedure is: 1) noninvasive, because only a standard monocular endoscope and a surgical tool are used; 2) convenient, because only a hand-controlled exploratory motion is needed; 3) fast, because the algorithm provides the 3-D map and the trajectory in real time; 4) accurate, because it has been validated with respect to ground-truth; and 5) robust to inter-patient variability, because it has performed successfully over the validation sequences.

  7. Extending Driving Vision Based on Image Mosaic Technique

    Directory of Open Access Journals (Sweden)

    Chen Deng

    2017-01-01

    Full Text Available Car cameras have been used extensively to assist driving by make driving visible. However, due to the limitation of the Angle of View (AoV, the dead zone still exists, which is a primary origin of car accidents. In this paper, we introduce a system to extend the vision of drivers to 360 degrees. Our system consists of four wide-angle cameras, which are mounted at different sides of a car. Although the AoV of each camera is within 180 degrees, relying on the image mosaic technique, our system can seamlessly integrate 4-channel videos into a panorama video. The panorama video enable drivers to observe everywhere around a car as far as three meters from a top view. We performed experiments in a laboratory environment. Preliminary results show that our system can eliminate vision dead zone completely. Additionally, the real-time performance of our system can satisfy requirements for practical use.

  8. An Analytical Measuring Rectification Algorithm of Monocular Systems in Dynamic Environment

    Directory of Open Access Journals (Sweden)

    Deshi Li

    2016-01-01

    Full Text Available Range estimation is crucial for maintaining a safe distance, in particular for vision navigation and localization. Monocular autonomous vehicles are appropriate for outdoor environment due to their mobility and operability. However, accurate range estimation using vision system is challenging because of the nonholonomic dynamics and susceptibility of vehicles. In this paper, a measuring rectification algorithm for range estimation under shaking conditions is designed. The proposed method focuses on how to estimate range using monocular vision when a shake occurs and the algorithm only requires the pose variations of the camera to be acquired. Simultaneously, it solves the problem of how to assimilate results from different kinds of sensors. To eliminate measuring errors by shakes, we establish a pose-range variation model. Afterwards, the algebraic relation between distance increment and a camera’s poses variation is formulated. The pose variations are presented in the form of roll, pitch, and yaw angle changes to evaluate the pixel coordinate incensement. To demonstrate the superiority of our proposed algorithm, the approach is validated in a laboratory environment using Pioneer 3-DX robots. The experimental results demonstrate that the proposed approach improves in the range accuracy significantly.

  9. Visions and visioning in foresight activities

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard; Grosu, Dan

    2007-01-01

    The paper discusses the roles of visioning processes and visions in foresight activities and in societal discourses and changes parallel to or following foresight activities. The overall topic can be characterised as the dynamics and mechanisms that make visions and visioning processes work...... or not work. The theoretical part of the paper presents an actor-network theory approach to the analyses of visions and visioning processes, where the shaping of the visions and the visioning and what has made them work or not work is analysed. The empirical part is based on analyses of the roles of visions...... and visioning processes in a number of foresight processes from different societal contexts. The analyses have been carried out as part of the work in the COST A22 network on foresight. A vision is here understood as a description of a desirable or preferable future, compared to a scenario which is understood...

  10. Micro Vision

    OpenAIRE

    Ohba, Kohtaro; OHARA, Kenichi

    2007-01-01

    In the field of the micro vision, there are few researches compared with macro environment. However, applying to the study result for macro computer vision technique, you can measure and observe the micro environment. Moreover, based on the effects of micro environment, it is possible to discovery the new theories and new techniques.

  11. Depth of Monocular Elements in a Binocular Scene: The Conditions for da Vinci Stereopsis

    Science.gov (United States)

    Cook, Michael; Gillam, Barbara

    2004-01-01

    Quantitative depth based on binocular resolution of visibility constraints is demonstrated in a novel stereogram representing an object, visible to 1 eye only, and seen through an aperture or camouflaged against a background. The monocular region in the display is attached to the binocular region, so that the stereogram represents an object which…

  12. Depth of Monocular Elements in a Binocular Scene: The Conditions for da Vinci Stereopsis

    Science.gov (United States)

    Cook, Michael; Gillam, Barbara

    2004-01-01

    Quantitative depth based on binocular resolution of visibility constraints is demonstrated in a novel stereogram representing an object, visible to 1 eye only, and seen through an aperture or camouflaged against a background. The monocular region in the display is attached to the binocular region, so that the stereogram represents an object which…

  13. Proceedings of the First International Workshop on Generative-Model-Based Vision

    DEFF Research Database (Denmark)

    In the last decade, there has been a convergence of statistical and model-based approaches to computational vision. This is an ongoing process, leading to the emerging paradigm of generative-model-based (GMB) vision. This workshop/special issue aims to bring together researchers working...... on different problems within computational vision, who are interested in this paradigm. For the purposes of the workshop/special issue, GMB vision is a methodology which prescribes * the formulation of a parameterized probabilistic model of image generation; * estimation and/or maximization of the posterior...... probability (given an image or image sequence) of model parameters (state variables). Often, the generative model is used not only by the software developer in the formulation of the algorithm, but also by the algorithm itself as a component of an iterative estimation process. The state variables are whatever...

  14. Proceedinsg of the Second International workshop on Generative-Model Based Vision

    DEFF Research Database (Denmark)

    In the last decade, there has been a convergence of statistical and model-based approaches to computational vision. This is an ongoing process, leading to the emerging paradigm of generative-model-based (GMB) vision. This workshop/special issue aims to bring together researchers working...... on different problems within computational vision, who are interested in this paradigm. For the purposes of the workshop/special issue, GMB vision is a methodology which prescribes * the formulation of a parameterized probabilistic model of image generation; * estimation and/or maximization of the posterior...... probability (given an image or image sequence) of model parameters (state variables). Often, the generative model is used not only by the software developer in the formulation of the algorithm, but also by the algorithm itself as a component of an iterative estimation process. The state variables are whatever...

  15. Effect of ophthalmic filter thickness on predicted monocular dichromatic luminance and chromaticity discrimination.

    Science.gov (United States)

    Richer, S P; Little, A C; Adams, A J

    1984-11-01

    The majority of ophthalmic filters, whether they be in the form of spectacles or contact lenses, are absorbance type filters. Although color vision researchers routinely provide spectrophotometric transmission profiles of filters, filter thickness is rarely specified. In this paper, colorimetric tools and volume color theory are used to show that the color of a filter as well as its physical properties are altered dramatically by changes in thickness. The effect of changes in X-Chrom filter thickness on predicted monocular dichromatic luminance and chromaticity discrimination is presented.

  16. Three-dimensional microscope vision system based on micro laser line scanning and adaptive genetic algorithms

    Science.gov (United States)

    Apolinar, J.; Rodríguez, Muñoz

    2017-02-01

    A microscope vision system to retrieve small metallic surface via micro laser line scanning and genetic algorithms is presented. In this technique, a 36 μm laser line is projected on the metallic surface through a laser diode head, which is placed to a small distance away from the target. The micro laser line is captured by a CCD camera, which is attached to the microscope. The surface topography is computed by triangulation by means of the line position and microscope vision parameters. The calibration of the microscope vision system is carried out by an adaptive genetic algorithm based on the line position. In this algorithm, an objective function is constructed from the microscope geometry to determine the microscope vision parameters. Also, the genetic algorithm provides the search space to calculate the microscope vision parameters with high accuracy in fast form. This procedure avoids errors produced by the missing of references and physical measurements, which are employed by the traditional microscope vision systems. The contribution of the proposed system is corroborated by an evaluation via accuracy and speed of the traditional microscope vision systems, which retrieve micro-scale surface topography.

  17. A Novel Metric Online Monocular SLAM Approach for Indoor Applications

    Directory of Open Access Journals (Sweden)

    Yongfei Li

    2016-01-01

    Full Text Available Monocular SLAM has attracted more attention recently due to its flexibility and being economic. In this paper, a novel metric online direct monocular SLAM approach is proposed, which can obtain the metric reconstruction of the scene. In the proposed approach, a chessboard is utilized to provide initial depth map and scale correction information during the SLAM process. The involved chessboard provides the absolute scale of scene, and it is seen as a bridge between the camera visual coordinate and the world coordinate. The scene is reconstructed as a series of key frames with their poses and correlative semidense depth maps, using a highly accurate pose estimation achieved by direct grid point-based alignment. The estimated pose is coupled with depth map estimation calculated by filtering over a large number of pixelwise small-baseline stereo comparisons. In addition, this paper formulates the scale-drift model among key frames and the calibration chessboard is used to correct the accumulated pose error. At the end of this paper, several indoor experiments are conducted. The results suggest that the proposed approach is able to achieve higher reconstruction accuracy when compared with the traditional LSD-SLAM approach. And the approach can also run in real time on a commonly used computer.

  18. Robotics Vision-based Heuristic Reasoning for Underwater Target Tracking and Navigation

    OpenAIRE

    Chua Kia; Mohd. Rizal Arshad

    2005-01-01

    This paper presents a robotics vision-based heuristic reasoning system for underwater target tracking and navigation. This system is introduced to improve the level of automation of underwater Remote Operated Vehicles (ROVs) operations. A prototype which combines computer vision with an underwater robotics system is successfully designed and developed to perform target tracking and intelligent navigation. This study focuses on developing image processing algorithms and fuzzy inference system ...

  19. Development of a Vision-Based Robotic Follower Vehicle

    Science.gov (United States)

    2009-02-01

    système prédécesseur / suiveur à vision artificielle. Le but est d’aboutir éventuellement à des systèmes d’escorte autonome en matière de logistique ...2009-026 ; R & D pour la défense Canada – Suffield ; février 2009. Contexte : Les véhicules logistiques et leurs chauffeurs sont beaucoup plus...l’implémentant sur des véhicules de logistique militaire. . DRDC Suffield TR 2009-026 v This page intentionally left blank. vi DRDC Suffield TR 2009-026

  20. Vision-based pedestrian protection systems for intelligent vehicles

    CERN Document Server

    Geronimo, David

    2013-01-01

    Pedestrian Protection Systems (PPSs) are on-board systems aimed at detecting and tracking people in the surroundings of a vehicle in order to avoid potentially dangerous situations. These systems, together with other Advanced Driver Assistance Systems (ADAS) such as lane departure warning or adaptive cruise control, are one of the most promising ways to improve traffic safety. By the use of computer vision, cameras working either in the visible or infra-red spectra have been demonstrated as a reliable sensor to perform this task. Nevertheless, the variability of human's appearance, not only in

  1. Personal and organisational vision supporting leadership in a team-based transport environment

    Directory of Open Access Journals (Sweden)

    Theuns F.J. Oosthuizen

    2012-11-01

    Full Text Available Leadership in an operational environment requires operational employees to take on responsibility as leaders. This leadership role could vary from self-leadership to team leadership with personal and organisational vision as key drivers for operational leadership performance. The research population included operational employees working in a transport environment who attended a leadership development seminar. A census was conducted using a questionnaire-based empirical research approach. Data analysis was conducted using SPSS, and the results were analysed. Responses indicate the development of an awareness of the importance of values and vision in order to establish effective leadership practices through the leadership development programme. Research confirmed the importance of vision as a key driver in operational leadership in this context. Further skill development is required on how to align personal values and vision with that of the organisation (department within which operational employees function.

  2. Obstacle avoidance using predictive vision based on a dynamic 3D world model

    Science.gov (United States)

    Benjamin, D. Paul; Lyons, Damian; Achtemichuk, Tom

    2006-10-01

    We have designed and implemented a fast predictive vision system for a mobile robot based on the principles of active vision. This vision system is part of a larger project to design a comprehensive cognitive architecture for mobile robotics. The vision system represents the robot's environment with a dynamic 3D world model based on a 3D gaming platform (Ogre3D). This world model contains a virtual copy of the robot and its environment, and outputs graphics showing what the virtual robot "sees" in the virtual world; this is what the real robot expects to see in the real world. The vision system compares this output in real time with the visual data. Any large discrepancies are flagged and sent to the robot's cognitive system, which constructs a plan for focusing on the discrepancies and resolving them, e.g. by updating the position of an object or by recognizing a new object. An object is recognized only once; thereafter its observed data are monitored for consistency with the predictions, greatly reducing the cost of scene understanding. We describe the implementation of this vision system and how the robot uses it to locate and avoid obstacles.

  3. An Active Stereo Vision System Based on Neural Pathways of Human Binocular Motor System

    Institute of Scientific and Technical Information of China (English)

    Yu-zhang Gu; Makoto Sato; Xiao-lin Zhang

    2007-01-01

    An active stereo vision system based on a model of neural pathways of human binocular motor system is proposed. With this model, it is guaranteed that the two cameras of the active stereo vision system can keep their lines of sight fixed on the same target object during smooth pursuit. This feature is very important for active stereo vision systems, since not only 3D reconstruction needs the two cameras have an overlapping field of vision, but also it can facilitate the 3D reconstruction algorithm. To evaluate the effectiveness of the proposed method, some software simulations are done to demonstrate the same target tracking characteristic in a virtual environment apt to mistracking easily. Here, mistracking means two eyes track two different objects separately. Then the proposed method is implemented in our active stereo vision system to perform real tracking task in a laboratory scene where several persons walk self-determining. Before the proposed model is implemented in the system, mistracking occurred frequently. After it is enabled, mistracking never occurred. The result shows that the vision system based on neural pathways of human binocular motor system can reliably avoid mistracking.

  4. Monocular Elevation Deficiency - Double Elevator Palsy

    Science.gov (United States)

    ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ...

  5. Human vision is determined based on information theory.

    Science.gov (United States)

    Delgado-Bonal, Alfonso; Martín-Torres, Javier

    2016-11-03

    It is commonly accepted that the evolution of the human eye has been driven by the maximum intensity of the radiation emitted by the Sun. However, the interpretation of the surrounding environment is constrained not only by the amount of energy received but also by the information content of the radiation. Information is related to entropy rather than energy. The human brain follows Bayesian statistical inference for the interpretation of visual space. The maximization of information occurs in the process of maximizing the entropy. Here, we show that the photopic and scotopic vision absorption peaks in humans are determined not only by the intensity but also by the entropy of radiation. We suggest that through the course of evolution, the human eye has not adapted only to the maximum intensity or to the maximum information but to the optimal wavelength for obtaining information. On Earth, the optimal wavelengths for photopic and scotopic vision are 555 nm and 508 nm, respectively, as inferred experimentally. These optimal wavelengths are determined by the temperature of the star (in this case, the Sun) and by the atmospheric composition.

  6. Human vision is determined based on information theory

    Science.gov (United States)

    Delgado-Bonal, Alfonso; Martín-Torres, Javier

    2016-11-01

    It is commonly accepted that the evolution of the human eye has been driven by the maximum intensity of the radiation emitted by the Sun. However, the interpretation of the surrounding environment is constrained not only by the amount of energy received but also by the information content of the radiation. Information is related to entropy rather than energy. The human brain follows Bayesian statistical inference for the interpretation of visual space. The maximization of information occurs in the process of maximizing the entropy. Here, we show that the photopic and scotopic vision absorption peaks in humans are determined not only by the intensity but also by the entropy of radiation. We suggest that through the course of evolution, the human eye has not adapted only to the maximum intensity or to the maximum information but to the optimal wavelength for obtaining information. On Earth, the optimal wavelengths for photopic and scotopic vision are 555 nm and 508 nm, respectively, as inferred experimentally. These optimal wavelengths are determined by the temperature of the star (in this case, the Sun) and by the atmospheric composition.

  7. Deep monocular 3D reconstruction for assisted navigation in bronchoscopy.

    Science.gov (United States)

    Visentini-Scarzanella, Marco; Sugiura, Takamasa; Kaneko, Toshimitsu; Koto, Shinichiro

    2017-07-01

    In bronchoschopy, computer vision systems for navigation assistance are an attractive low-cost solution to guide the endoscopist to target peripheral lesions for biopsy and histological analysis. We propose a decoupled deep learning architecture that projects input frames onto the domain of CT renderings, thus allowing offline training from patient-specific CT data. A fully convolutional network architecture is implemented on GPU and tested on a phantom dataset involving 32 video sequences and [Formula: see text]60k frames with aligned ground truth and renderings, which is made available as the first public dataset for bronchoscopy navigation. An average estimated depth accuracy of 1.5 mm was obtained, outperforming conventional direct depth estimation from input frames by 60%, and with a computational time of [Formula: see text]30 ms on modern GPUs. Qualitatively, the estimated depth and renderings closely resemble the ground truth. The proposed method shows a novel architecture to perform real-time monocular depth estimation without losing patient specificity in bronchoscopy. Future work will include integration within SLAM systems and collection of in vivo datasets.

  8. Monocular visual scene understanding: understanding multi-object traffic scenes.

    Science.gov (United States)

    Wojek, Christian; Walk, Stefan; Roth, Stefan; Schindler, Konrad; Schiele, Bernt

    2013-04-01

    Following recent advances in detection, context modeling, and tracking, scene understanding has been the focus of renewed interest in computer vision research. This paper presents a novel probabilistic 3D scene model that integrates state-of-the-art multiclass object detection, object tracking and scene labeling together with geometric 3D reasoning. Our model is able to represent complex object interactions such as inter-object occlusion, physical exclusion between objects, and geometric context. Inference in this model allows us to jointly recover the 3D scene context and perform 3D multi-object tracking from a mobile observer, for objects of multiple categories, using only monocular video as input. Contrary to many other approaches, our system performs explicit occlusion reasoning and is therefore capable of tracking objects that are partially occluded for extended periods of time, or objects that have never been observed to their full extent. In addition, we show that a joint scene tracklet model for the evidence collected over multiple frames substantially improves performance. The approach is evaluated for different types of challenging onboard sequences. We first show a substantial improvement to the state of the art in 3D multipeople tracking. Moreover, a similar performance gain is achieved for multiclass 3D tracking of cars and trucks on a challenging dataset.

  9. Patterns of non-embolic transient monocular visual field loss.

    Science.gov (United States)

    Petzold, Axel; Islam, Niaz; Plant, G T

    2013-07-01

    The aim of this study was to systematically describe the semiology of non-embolic transient monocular visual field loss (neTMVL). We conducted a retrospective case note analysis of patients from Moorfields Eye Hospital (1995-2007). The variables analysed were age, age of onset, gender, past medical history or family history of migraine, eye affected, onset, duration and offset, perception (pattern, positive and negative symptoms), associated headache and autonomic symptoms, attack frequency, and treatment response to nifedipine. We identified 77 patients (28 male and 49 female). Mean age of onset was 37 years (range 14-77 years). The neTMVL was limited to the right eye in 36 % to the left in 47 % and occurred independently in either eye in 5 % of cases. A past medical history of migraine was present in 12 % and a family history in 8 %. Headache followed neTMVL in 14 % and was associated with autonomic features in 3 %. The neTMB was perceived as grey in 35 %, white in 21 %, black in 16 % and as phosphenes in 9 %. Most frequently neTMVL was patchy 20 %. Recovery of vision frequently resembled attack onset in reverse. In 3 patients without associated headache the loss of vision was permanent. Treatment with nifedipine was initiated in 13 patients with an attack frequency of more than one per week and reduced the attack frequency in all. In conclusion, this large series of patients with neTMVL permits classification into five types of reversible visual field loss (grey, white, black, phosphenes, patchy). Treatment response to nifidipine suggests some attacks to be caused by vasospasm.

  10. Reference Sphere Positioning Measurement Based on Line-Structured Light Vision Sensor

    Directory of Open Access Journals (Sweden)

    Bin Wu

    2013-01-01

    Full Text Available The line-structured light vision sensor has been used widely in industrial vision measuring fields due to its simple structure, small volume, light weight, low cost, convenient calibration, and high accuracy of measurement. To locate the reference sphere precisely with line-structured light vision sensor, a mathematical model based on the measuring principle of line-structured light vision sensor is established in the paper. Then, the positioning measurement error is analyzed in detail. The experimental results show that the method is valid and correct. In addition, an accurate measurement area which is from R0 × sin 45° to R0 × sin 75° away from the center of reference sphere is delimited through the statistical analysis of the experimental data. For the robot temperature compensation and calibration of flexible vision measurement system, this method effectively solves the positioning measurement problems about reference sphere with line-structured light vision sensor and has been applied in the industrial flexible online measurement systems successfully.

  11. Human skeleton proportions from monocular data

    Institute of Scientific and Technical Information of China (English)

    PENG En; LI Ling

    2006-01-01

    This paper introduces a novel method for estimating the skeleton proportions ofa human figure from monocular data.The proposed system will first automatically extract the key frames and recover the perspective camera model from the 2D data.The human skeleton proportions are then estimated from the key frames using the recovered camera model without posture reconstruction. The proposed method is tested to be simple, fast and produce satisfactory results for the input data. The human model with estimated proportions can be used in future research involving human body modeling or human motion reconstruction.

  12. The effect of a monocular helmet-mounted display on aircrew health: a 10-year prospective cohort study of Apache AH MK 1 pilots: study midpoint update

    Science.gov (United States)

    Hiatt, Keith L.; Rash, Clarence E.; Watters, Raymond W.; Adams, Mark S.

    2009-05-01

    A collaborative occupational health study has been undertaken by Headquarters Army Aviation, Middle Wallop, UK, and the U.S. Army Aeromedical Research Laboratory, Fort Rucker, Alabama, to determine if the use of the Integrated Helmet and Display Sighting System (IHADSS) monocular helmet-mounted display (HMD) in the Apache AH Mk 1 attack helicopter has any long-term (10-year) effect on visual performance. The test methodology consists primarily of a detailed questionnaire and an annual battery of vision tests selected to capture changes in visual performance of Apache aviators over their flight career (with an emphasis on binocular visual function). Pilots using binocular night vision goggles serve as controls and undergo the same methodology. Currently, at the midpoint of the study, with the exception of a possible colour discrimination effect, there are no data indicating that the long-term use of the IHADSS monocular HMD results in negative effects on vision.

  13. Vision based object pose estimation for mobile robots

    Science.gov (United States)

    Wu, Annie; Bidlack, Clint; Katkere, Arun; Feague, Roy; Weymouth, Terry

    1994-01-01

    Mobile robot navigation using visual sensors requires that a robot be able to detect landmarks and obtain pose information from a camera image. This paper presents a vision system for finding man-made markers of known size and calculating the pose of these markers. The algorithm detects and identifies the markers using a weighted pattern matching template. Geometric constraints are then used to calculate the position of the markers relative to the robot. The selection of geometric constraints comes from the typical pose of most man-made signs, such as the sign standing vertical and the dimensions of known size. This system has been tested successfully on a wide range of real images. Marker detection is reliable, even in cluttered environments, and under certain marker orientations, estimation of the orientation has proven accurate to within 2 degrees, and distance estimation to within 0.3 meters.

  14. Episodic Reasoning for Vision-Based Human Action Recognition

    Directory of Open Access Journals (Sweden)

    Maria J. Santofimia

    2014-01-01

    Full Text Available Smart Spaces, Ambient Intelligence, and Ambient Assisted Living are environmental paradigms that strongly depend on their capability to recognize human actions. While most solutions rest on sensor value interpretations and video analysis applications, few have realized the importance of incorporating common-sense capabilities to support the recognition process. Unfortunately, human action recognition cannot be successfully accomplished by only analyzing body postures. On the contrary, this task should be supported by profound knowledge of human agency nature and its tight connection to the reasons and motivations that explain it. The combination of this knowledge and the knowledge about how the world works is essential for recognizing and understanding human actions without committing common-senseless mistakes. This work demonstrates the impact that episodic reasoning has in improving the accuracy of a computer vision system for human action recognition. This work also presents formalization, implementation, and evaluation details of the knowledge model that supports the episodic reasoning.

  15. GPU-based real-time trinocular stereo vision

    Science.gov (United States)

    Yao, Yuanbin; Linton, R. J.; Padir, Taskin

    2013-01-01

    Most stereovision applications are binocular which uses information from a 2-camera array to perform stereo matching and compute the depth image. Trinocular stereovision with a 3-camera array has been proved to provide higher accuracy in stereo matching which could benefit applications like distance finding, object recognition, and detection. This paper presents a real-time stereovision algorithm implemented on a GPGPU (General-purpose graphics processing unit) using a trinocular stereovision camera array. Algorithm employs a winner-take-all method applied to perform fusion of disparities in different directions following various image processing techniques to obtain the depth information. The goal of the algorithm is to achieve real-time processing speed with the help of a GPGPU involving the use of Open Source Computer Vision Library (OpenCV) in C++ and NVidia CUDA GPGPU Solution. The results are compared in accuracy and speed to verify the improvement.

  16. State-Estimation Algorithm Based on Computer Vision

    Science.gov (United States)

    Bayard, David; Brugarolas, Paul

    2007-01-01

    An algorithm and software to implement the algorithm are being developed as means to estimate the state (that is, the position and velocity) of an autonomous vehicle, relative to a visible nearby target object, to provide guidance for maneuvering the vehicle. In the original intended application, the autonomous vehicle would be a spacecraft and the nearby object would be a small astronomical body (typically, a comet or asteroid) to be explored by the spacecraft. The algorithm could also be used on Earth in analogous applications -- for example, for guiding underwater robots near such objects of interest as sunken ships, mineral deposits, or submerged mines. It is assumed that the robot would be equipped with a vision system that would include one or more electronic cameras, image-digitizing circuitry, and an imagedata- processing computer that would generate feature-recognition data products.

  17. More clinical observations on migraine associated with monocular visual symptoms in an Indian population

    Directory of Open Access Journals (Sweden)

    Vishal Jogi

    2016-01-01

    Full Text Available Context: Retinal migraine (RM is considered as one of the rare causes of transient monocular visual loss (TMVL and has not been studied in Indian population. Objectives: The study aims to analyze the clinical and investigational profile of patients with RM. Materials and Methods: This is an observational prospective analysis of 12 cases of TMVL fulfilling the International Classification of Headache Disorders-2nd edition (ICHD-II criteria of RM examined in Neurology and Ophthalmology Outpatient Department (OPD of Postgraduate Institute of Medical Education and Research (PGIMER, Chandigarh from July 2011 to October 2012. Results: Most patients presented in 3 rd and 4 th decade with equal sex distribution. Seventy-five percent had antecedent migraine without aura (MoA and 25% had migraine with Aura (MA. Headache was ipsilateral to visual symptoms in 67% and bilateral in 33%. TMVL preceded headache onset in 58% and occurred during headache episode in 42%. Visual symptoms were predominantly negative except in one patient who had positive followed by negative symptoms. Duration of visual symptoms was variable ranging from 30 s to 45 min. None of the patient had permanent monocular vision loss. Three patients had episodes of TMVL without headache in addition to the symptom constellation defining RM. Most of the tests done to rule out alternative causes were normal. Magnetic resonance imaging (MRI brain showed nonspecific white matter changes in one patient. Visual-evoked potential (VEP showed prolonged P100 latencies in two cases. Patent foramen ovale was detected in one patient. Conclusions: RM is a definite subtype of migraine and should remain in the ICHD classification. It should be kept as one of the differential diagnosis of transient monocular vision loss. We propose existence of "acephalgic RM" which may respond to migraine prophylaxis.

  18. Monocular Obstacle Detection for Real-World Environments

    Science.gov (United States)

    Einhorn, Erik; Schroeter, Christof; Gross, Horst-Michael

    In this paper, we present a feature based approach for monocular scene reconstruction based on extended Kaiman filters (EKF). Our method processes a sequence of images taken by a single camera mounted in front of a mobile robot. Using various techniques we are able to produce a precise reconstruction that is almost free from outliers and therefore can be used for reliable obstacle detection and avoidance. In real-world field tests we show that the presented approach is able to detect obstacles that can not be seen by other sensors, such as laser range finders. Furthermore, we show that visual obstacle detection combined with a laser range finder can increase the detection rate of obstacles considerably, allowing the autonomous use of mobile robots in complex public and home environments.

  19. Vision-Based Unmanned Aerial Vehicle Navigation Using Geo-Referenced Information

    Science.gov (United States)

    Conte, Gianpaolo; Doherty, Patrick

    2009-12-01

    This paper investigates the possibility of augmenting an Unmanned Aerial Vehicle (UAV) navigation system with a passive video camera in order to cope with long-term GPS outages. The paper proposes a vision-based navigation architecture which combines inertial sensors, visual odometry, and registration of the on-board video to a geo-referenced aerial image. The vision-aided navigation system developed is capable of providing high-rate and drift-free state estimation for UAV autonomous navigation without the GPS system. Due to the use of image-to-map registration for absolute position calculation, drift-free position performance depends on the structural characteristics of the terrain. Experimental evaluation of the approach based on offline flight data is provided. In addition the architecture proposed has been implemented on-board an experimental UAV helicopter platform and tested during vision-based autonomous flights.

  20. Vision-Based Unmanned Aerial Vehicle Navigation Using Geo-Referenced Information

    Directory of Open Access Journals (Sweden)

    Gianpaolo Conte

    2009-01-01

    Full Text Available This paper investigates the possibility of augmenting an Unmanned Aerial Vehicle (UAV navigation system with a passive video camera in order to cope with long-term GPS outages. The paper proposes a vision-based navigation architecture which combines inertial sensors, visual odometry, and registration of the on-board video to a geo-referenced aerial image. The vision-aided navigation system developed is capable of providing high-rate and drift-free state estimation for UAV autonomous navigation without the GPS system. Due to the use of image-to-map registration for absolute position calculation, drift-free position performance depends on the structural characteristics of the terrain. Experimental evaluation of the approach based on offline flight data is provided. In addition the architecture proposed has been implemented on-board an experimental UAV helicopter platform and tested during vision-based autonomous flights.

  1. Multi-Purpose Avionic Architecture for Vision Based Navigation Systems for EDL and Surface Mobility Scenarios

    Science.gov (United States)

    Tramutola, A.; Paltro, D.; Cabalo Perucha, M. P.; Paar, G.; Steiner, J.; Barrio, A. M.

    2015-09-01

    Vision Based Navigation (VBNAV) has been identified as a valid technology to support space exploration because it can improve autonomy and safety of space missions. Several mission scenarios can benefit from the VBNAV: Rendezvous & Docking, Fly-Bys, Interplanetary cruise, Entry Descent and Landing (EDL) and Planetary Surface exploration. For some of them VBNAV can improve the accuracy in state estimation as additional relative navigation sensor or as absolute navigation sensor. For some others, like surface mobility and terrain exploration for path identification and planning, VBNAV is mandatory. This paper presents the general avionic architecture of a Vision Based System as defined in the frame of the ESA R&T study “Multi-purpose Vision-based Navigation System Engineering Model - part 1 (VisNav-EM-1)” with special focus on the surface mobility application.

  2. Research on Extraction of Bottom of Shoe Pattern Based on Binocular Stereo Vision

    Institute of Scientific and Technical Information of China (English)

    MA Xin-wu; GAN Yi; SUN Fu-jia

    2016-01-01

    In order to quickly and efficiently get the information of the bottom of the shoe pattern and spraying trajectory, the paper proposes a method based on binocular stereo vision .After acquiring target image , edge detection based on the canny algorithm , the paper begins stereo matching based on area and characteristics of algorithm.To eliminate false matching points , the paper uses the principle of polar geometry in computer vision . For the purpose of gaining the 3D point cloud of spraying curve , the paper adopts the principle of binocular stereo vision 3D measurement , and then carries on cubic spline curve fitting .By HALCON image processing software programming , it proves the feasibility and effectiveness of the method .

  3. Research and application of visual location technology for solder paste printing based on machine vision

    Institute of Scientific and Technical Information of China (English)

    Luosi WEI; Zongxia JIAO

    2009-01-01

    A location system is very important for solder paste printing in the process of surface mount technology (SMT). Using machine vision technology to complete the location mission is new and very efficient. This paper presents an integrated visual location system for solder paste printing based on machine vision. The working principle of solder paste printing is introduced and then the design and implementation of the visual location system are described. In the system, two key techniques are completed by secondary development based on VisionPro.One is accurate image location solved by the pattern-based location algorithms of PatMax. The other one is camera calibration that is achieved by image warping technology through the checkerboard plate. Moreover, the system can provide good performances such as high image locating accuracy with 1/40 sub-pixels, high anti-jamming, and high-speed location of objects whose appearance is rotated, scaled, and/or stretched.

  4. Monocular tool control, eye dominance, and laterality in New Caledonian crows.

    Science.gov (United States)

    Martinho, Antone; Burns, Zackory T; von Bayern, Auguste M P; Kacelnik, Alex

    2014-12-15

    Tool use, though rare, is taxonomically widespread, but morphological adaptations for tool use are virtually unknown. We focus on the New Caledonian crow (NCC, Corvus moneduloides), which displays some of the most innovative tool-related behavior among nonhumans. One of their major food sources is larvae extracted from burrows with sticks held diagonally in the bill, oriented with individual, but not species-wide, laterality. Among possible behavioral and anatomical adaptations for tool use, NCCs possess unusually wide binocular visual fields (up to 60°), suggesting that extreme binocular vision may facilitate tool use. Here, we establish that during natural extractions, tool tips can only be viewed by the contralateral eye. Thus, maintaining binocular view of tool tips is unlikely to have selected for wide binocular fields; the selective factor is more likely to have been to allow each eye to see far enough across the midsagittal line to view the tool's tip monocularly. Consequently, we tested the hypothesis that tool side preference follows eye preference and found that eye dominance does predict tool laterality across individuals. This contrasts with humans' species-wide motor laterality and uncorrelated motor-visual laterality, possibly because bill-held tools are viewed monocularly and move in concert with eyes, whereas hand-held tools are visible to both eyes and allow independent combinations of eye preference and handedness. This difference may affect other models of coordination between vision and mechanical control, not necessarily involving tools. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. 78 FR 68475 - Certain Vision-Based Driver Assistance System Cameras and Components Thereof; Institution of...

    Science.gov (United States)

    2013-11-14

    ... COMMISSION Certain Vision-Based Driver Assistance System Cameras and Components Thereof; Institution of...-based driver assistance system cameras and components thereof by reason of infringement of certain... assistance system cameras and components thereof by reason of infringement of one or more of claims 1, 2,...

  6. Affordance estimation for vision-based object replacement on a humanoid robot

    DEFF Research Database (Denmark)

    Mustafa, Wail; Wächter, Mirko; Szedmak, Sandor

    2016-01-01

    In this paper, we address the problem of finding replacements of missing objects, involved in the execution of manipulation tasks. Our approach is based on estimating functional affordances for the unknown objects in order to propose replacements. We use a vision-based affordance estimation syste...

  7. Design of a vision-based sensor for autonomous pighouse cleaning

    DEFF Research Database (Denmark)

    Braithwaite, Ian David; Blanke, Mogens; Zhang, Guo-Quiang

    2005-01-01

    of designing a vision-based system to locate dirty areas and subsequently direct a cleaning robot to remove dirt. Novel results include the characterisation of the spectral properties of real surfaces and dirt in a pig house and the design of illumination to obtain discrimination of clean from dirty areas...... with a low probability of misclassification. A Bayesian discriminator is shown to be efficient in this context and implementation of a prototype tool demonstrates the feasibility of designing a low-cost vision-based sensor for autonomous cleaning....

  8. Design of a vision-based sensor for autonomous pighouse cleaning

    DEFF Research Database (Denmark)

    Braithwaite, Ian David; Blanke, Mogens; Zhang, Guo-Quiang;

    2005-01-01

    of designing a vision-based system to locate dirty areas and subsequently direct a cleaning robot to remove dirt. Novel results include the characterisation of the spectral properties of real surfaces and dirt in a pig house and the design of illumination to obtain discrimination of clean from dirty areas...... with a low probability of misclassification. A Bayesian discriminator is shown to be efficient in this context and implementation of a prototype tool demonstrates the feasibility of designing a low-cost vision-based sensor for autonomous cleaning....

  9. Simulated Prosthetic Vision: The Benefits of Computer-Based Object Recognition and Localization.

    Science.gov (United States)

    Macé, Marc J-M; Guivarch, Valérian; Denis, Grégoire; Jouffrais, Christophe

    2015-07-01

    Clinical trials with blind patients implanted with a visual neuroprosthesis showed that even the simplest tasks were difficult to perform with the limited vision restored with current implants. Simulated prosthetic vision (SPV) is a powerful tool to investigate the putative functions of the upcoming generations of visual neuroprostheses. Recent studies based on SPV showed that several generations of implants will be required before usable vision is restored. However, none of these studies relied on advanced image processing. High-level image processing could significantly reduce the amount of information required to perform visual tasks and help restore visuomotor behaviors, even with current low-resolution implants. In this study, we simulated a prosthetic vision device based on object localization in the scene. We evaluated the usability of this device for object recognition, localization, and reaching. We showed that a very low number of electrodes (e.g., nine) are sufficient to restore visually guided reaching movements with fair timing (10 s) and high accuracy. In addition, performance, both in terms of accuracy and speed, was comparable with 9 and 100 electrodes. Extraction of high level information (object recognition and localization) from video images could drastically enhance the usability of current visual neuroprosthesis. We suggest that this method-that is, localization of targets of interest in the scene-may restore various visuomotor behaviors. This method could prove functional on current low-resolution implants. The main limitation resides in the reliability of the vision algorithms, which are improving rapidly.

  10. Vision-based obstacle recognition system for automated lawn mower robot development

    Science.gov (United States)

    Mohd Zin, Zalhan; Ibrahim, Ratnawati

    2011-06-01

    Digital image processing techniques (DIP) have been widely used in various types of application recently. Classification and recognition of a specific object using vision system require some challenging tasks in the field of image processing and artificial intelligence. The ability and efficiency of vision system to capture and process the images is very important for any intelligent system such as autonomous robot. This paper gives attention to the development of a vision system that could contribute to the development of an automated vision based lawn mower robot. The works involve on the implementation of DIP techniques to detect and recognize three different types of obstacles that usually exist on a football field. The focus was given on the study on different types and sizes of obstacles, the development of vision based obstacle recognition system and the evaluation of the system's performance. Image processing techniques such as image filtering, segmentation, enhancement and edge detection have been applied in the system. The results have shown that the developed system is able to detect and recognize various types of obstacles on a football field with recognition rate of more 80%.

  11. Robotic applications of VAM-based invariant representation for active vision

    Science.gov (United States)

    Srinivasa, Narayan; Sharma, Rajeev

    1996-03-01

    Active vision refers to a purposeful change in the camera setup to aid the processing of visual information. An important issue in using active vision is the need to represent the 3D environment in a manner that is invariant to changing camera configurations. Conventional methods require precise knowledge of various camera parameters in order to build this representation. However, these parameters are prone to calibration errors. This motivates us to explore a neural network based approach using Vector Associative Map to learn the invariant representation of 3D point targets for active vision. An efficient learning scheme is developed that is suitable for robotic implementation. The representation thus learned is also independent of the intrinsic parameters of the imaging system, making it immune to systematic calibration errors. To evaluate the effectiveness of this scheme, computer simulations were first performed using a detailed model of the University of Illinois Active Vision System (UIAVS). This is followed by an experimental verification on the actual UIAVS. Several robotic applications are then explored that utilize the invariance property of the learned representation. These applications include motion detection, active vision based robot control, robot motion planning, and saccade sequence planning.

  12. Three-dimensional profile reconstruction based on infrared multi-view vision

    Science.gov (United States)

    Zhao, Shuqi; Zhang, Zhimin; Wan, Xiong

    2016-09-01

    Multi-view vision technology is use of multiple images to reconstruct three-dimensional (3D) information of the research object, and the images were captured with more than two cameras from different angles. This technology has the advantages of high efficiency, simple structure and low cast. It is very suitable for on line noncontact product test and quality control. The existent multi-view vision technology is focus on the visible information, thus it is easy to be influenced by the testing environment (weather, background, light etc.), so it's application field has some limitations. However, in the field of medical diagnostic technology, infrared vision technology reflects its advantages, like determining whether the tissue lesions by observe certain parts temperature distribution of the body. This paper is studied on infrared Multi-vision which is based on visible binocular vision theory. Firstly, obtained the intrinsic parameter and external parameter of each infrared thermal imager by Zhang's calibration method; Secondly, taken infrared images from different angles, then combined the infrared images two by two to do feature point detecting and matching in order to find the points to be reconstructed; Finally, reconstructing 3D profile information based on calculating point clouds of the spatial coordinates.

  13. Incremental inverse kinematics based vision servo for autonomous robotic capture of non-cooperative space debris

    Science.gov (United States)

    Dong, Gangqi; Zhu, Z. H.

    2016-04-01

    This paper proposed a new incremental inverse kinematics based vision servo approach for robotic manipulators to capture a non-cooperative target autonomously. The target's pose and motion are estimated by a vision system using integrated photogrammetry and EKF algorithm. Based on the estimated pose and motion of the target, the instantaneous desired position of the end-effector is predicted by inverse kinematics and the robotic manipulator is moved incrementally from its current configuration subject to the joint speed limits. This approach effectively eliminates the multiple solutions in the inverse kinematics and increases the robustness of the control algorithm. The proposed approach is validated by a hardware-in-the-loop simulation, where the pose and motion of the non-cooperative target is estimated by a real vision system. The simulation results demonstrate the effectiveness and robustness of the proposed estimation approach for the target and the incremental control strategy for the robotic manipulator.

  14. Implementation of Water Quality Management by Fish School Detection Based on Computer Vision Technology

    Directory of Open Access Journals (Sweden)

    Yan Hou

    2015-08-01

    Full Text Available To solve the detection of abnormal water quality, this study proposed a biological water abnormity detection method based on computer vision technology combined with Support Vector Machine (SVM. First, computer vision is used to acquire the parameters of fish school motion feature which can reflect the water quality and then these parameters were preprocessed. Next, the sample set is established and the water quality abnormity monitoring model based on computer vision technology combined with SVM is acquired. At last, the model is used to analyze and evaluate the motion characteristic parameters of fish school under unknown water, in order to indirectly monitor the situation of water quality. In view of great influence of kernel function and parameter optimization to the model, this study compared different kinds of kernel function and then made optimization selection using Particle Swarm Optimization (PSO, Genetic Algorithm (GA and grid search. The results obtained demonstrate that, that method is effective for monitoring water quality abnormity.

  15. Vision-based flight control in the hawkmoth Hyles lineata.

    Science.gov (United States)

    Windsor, Shane P; Bomphrey, Richard J; Taylor, Graham K

    2014-02-06

    Vision is a key sensory modality for flying insects, playing an important role in guidance, navigation and control. Here, we use a virtual-reality flight simulator to measure the optomotor responses of the hawkmoth Hyles lineata, and use a published linear-time invariant model of the flight dynamics to interpret the function of the measured responses in flight stabilization and control. We recorded the forces and moments produced during oscillation of the visual field in roll, pitch and yaw, varying the temporal frequency, amplitude or spatial frequency of the stimulus. The moths' responses were strongly dependent upon contrast frequency, as expected if the optomotor system uses correlation-type motion detectors to sense self-motion. The flight dynamics model predicts that roll angle feedback is needed to stabilize the lateral dynamics, and that a combination of pitch angle and pitch rate feedback is most effective in stabilizing the longitudinal dynamics. The moths' responses to roll and pitch stimuli coincided qualitatively with these functional predictions. The moths produced coupled roll and yaw moments in response to yaw stimuli, which could help to reduce the energetic cost of correcting heading. Our results emphasize the close relationship between physics and physiology in the stabilization of insect flight.

  16. The Conformal Camera in Modeling Active Binocular Vision

    Directory of Open Access Journals (Sweden)

    Jacek Turski

    2016-08-01

    Full Text Available Primate vision is an active process that constructs a stable internal representation of the 3D world based on 2D sensory inputs that are inherently unstable due to incessant eye movements. We present here a mathematical framework for processing visual information for a biologically-mediated active vision stereo system with asymmetric conformal cameras. This model utilizes the geometric analysis on the Riemann sphere developed in the group-theoretic framework of the conformal camera, thus far only applicable in modeling monocular vision. The asymmetric conformal camera model constructed here includes the fovea’s asymmetric displacement on the retina and the eye’s natural crystalline lens tilt and decentration, as observed in ophthalmological diagnostics. We extend the group-theoretic framework underlying the conformal camera to the stereo system with asymmetric conformal cameras. Our numerical simulation shows that the theoretical horopter curves in this stereo system are conics that well approximate the empirical longitudinal horopters of the primate vision system.

  17. Binocular vision in amblyopia: structure, suppression and plasticity.

    Science.gov (United States)

    Hess, Robert F; Thompson, Benjamin; Baker, Daniel H

    2014-03-01

    The amblyopic visual system was once considered to be structurally monocular. However, it now evident that the capacity for binocular vision is present in many observers with amblyopia. This has led to new techniques for quantifying suppression that have provided insights into the relationship between suppression and the monocular and binocular visual deficits experienced by amblyopes. Furthermore, new treatments are emerging that directly target suppressive interactions within the visual cortex and, on the basis of initial data, appear to improve both binocular and monocular visual function, even in adults with amblyopia. The aim of this review is to provide an overview of recent studies that have investigated the structure, measurement and treatment of binocular vision in observers with strabismic, anisometropic and mixed amblyopia.

  18. Control system for solar tracking based on artificial vision; Sistema de control para seguimiento solar basado en vision artificial

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco Ramirez, Jesus Horacio; Anaya Perez, Maria Elena; Benitez Baltazar, Victor Hugo [Universidad de onora, Hermosillo, Sonora (Mexico)]. E-mail: jpacheco@industrial.uson.mx; meanaya@industrial.uson.mx; vbenitez@industrial.uson.mx

    2010-11-15

    This work shows how artificial vision feedback can be applied to control systems. The control is applied to a solar panel in order to track the sun position. The algorithms to calculate the position of the sun and the image processing are developed in LabView. The responses obtained from the control show that it is possible to use vision for a control scheme in closed loop. [Spanish] El presente trabajo muestra la manera en la cual un sistema de control puede ser retroalimentado mediante vision artificial. El control es aplicado en un panel solar para realizar el seguimiento del sol a lo largo del dia. Los algoritmos para calcular la posicion del sol y para el tratamiento de la imagen fueron desarrollados en LabView. Las respuestas obtenidas del control muestran que es posible utilizar vision para un esquema de control en lazo cerrado.

  19. Low Vision

    Science.gov (United States)

    ... HHS USAJobs Home > Statistics and Data > Low Vision Low Vision Low Vision Defined: Low Vision is defined as the ... Ethnicity 2010 U.S. Age-Specific Prevalence Rates for Low Vision by Age, and Race/Ethnicity Table for ...

  20. Function-based design process for an intelligent ground vehicle vision system

    Science.gov (United States)

    Nagel, Robert L.; Perry, Kenneth L.; Stone, Robert B.; McAdams, Daniel A.

    2010-10-01

    An engineering design framework for an autonomous ground vehicle vision system is discussed. We present both the conceptual and physical design by following the design process, development and testing of an intelligent ground vehicle vision system constructed for the 2008 Intelligent Ground Vehicle Competition. During conceptual design, the requirements for the vision system are explored via functional and process analysis considering the flows into the vehicle and the transformations of those flows. The conceptual design phase concludes with a vision system design that is modular in both hardware and software and is based on a laser range finder and camera for visual perception. During physical design, prototypes are developed and tested independently, following the modular interfaces identified during conceptual design. Prototype models, once functional, are implemented into the final design. The final vision system design uses a ray-casting algorithm to process camera and laser range finder data and identify potential paths. The ray-casting algorithm is a single thread of the robot's multithreaded application. Other threads control motion, provide feedback, and process sensory data. Once integrated, both hardware and software testing are performed on the robot. We discuss the robot's performance and the lessons learned.

  1. A Vision-Based Method for Autonomous Landing of a Rotor-Craft Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Z. Yuan

    2006-01-01

    Full Text Available This article introduces a real-time vision-based method for guided autonomous landing of a rotor-craft unmanned aerial vehicle. In the process of designing the pattern of landing target, we have fully considered how to make this easier for simplified identification and calibration. A linear algorithm was also applied using a three-dimensional structure estimation in real time. In addition, multiple-view vision technology is utilized to calibrate intrinsic parameters of camera online, so calibration prior to flight is unnecessary and the focus of camera can be changed freely in flight, thus upgrading the flexibility and practicality of the method.

  2. Machine vision based on the concept of contrast sensitivity of the human eye

    Science.gov (United States)

    Bezzubik, Vitali; Belashenkov, Nikolai; Vdovin, Gleb

    2014-09-01

    The model of contrast sensitivity function (CSF) of machine vision system, based on the CSF of the human visual system is proposed. By analogy with the human eye, we employ the concept of ganglion cell receptive field to the artificial light-sensitive elements. By further following this concept, we introduced quantative metrics of local and global contrast of digital image. We suggested that the contrast sensitivity threshold forms an iso-line in the parameter space contrast - spatial frequency. The model, implemented in a computer vision system, has been compared to the results of contrast sensitivity research, conducted directly with the human visual system, and demonstrated a good match.

  3. Autonomous navigation vehicle system based on robot vision and multi-sensor fusion

    Science.gov (United States)

    Wu, Lihong; Chen, Yingsong; Cui, Zhouping

    2011-12-01

    The architecture of autonomous navigation vehicle based on robot vision and multi-sensor fusion technology is expatiated in this paper. In order to acquire more intelligence and robustness, accurate real-time collection and processing of information are realized by using this technology. The method to achieve robot vision and multi-sensor fusion is discussed in detail. The results simulated in several operating modes show that this intelligent vehicle has better effects in barrier identification and avoidance and path planning. And this can provide higher reliability during vehicle running.

  4. Rehabilitation of patients with motor disabilities using computer vision based techniques

    Directory of Open Access Journals (Sweden)

    Alejandro Reyes-Amaro

    2012-05-01

    Full Text Available In this paper we present details about the implementation of computer vision based applications for the rehabilitation of patients with motor disabilities. The applications are conceived as serious games, where the computer-patient interaction during playing contributes to the development of different motor skills. The use of computer vision methods allows the automatic guidance of the patient’s movements making constant specialized supervision unnecessary. The hardware requirements are limited to low-cost devices like usual webcams and Netbooks.

  5. An assembly system based on industrial robot with binocular stereo vision

    Science.gov (United States)

    Tang, Hong; Xiao, Nanfeng

    2017-01-01

    This paper proposes an electronic part and component assembly system based on an industrial robot with binocular stereo vision. Firstly, binocular stereo vision with a visual attention mechanism model is used to get quickly the image regions which contain the electronic parts and components. Secondly, a deep neural network is adopted to recognize the features of the electronic parts and components. Thirdly, in order to control the end-effector of the industrial robot to grasp the electronic parts and components, a genetic algorithm (GA) is proposed to compute the transition matrix and the inverse kinematics of the industrial robot (end-effector), which plays a key role in bridging the binocular stereo vision and the industrial robot. Finally, the proposed assembly system is tested in LED component assembly experiments, and the results denote that it has high efficiency and good applicability.

  6. Camera calibration method of binocular stereo vision based on OpenCV

    Science.gov (United States)

    Zhong, Wanzhen; Dong, Xiaona

    2015-10-01

    Camera calibration, an important part of the binocular stereo vision research, is the essential foundation of 3D reconstruction of the spatial object. In this paper, the camera calibration method based on OpenCV (open source computer vision library) is submitted to make the process better as a result of obtaining higher precision and efficiency. First, the camera model in OpenCV and an algorithm of camera calibration are presented, especially considering the influence of camera lens radial distortion and decentering distortion. Then, camera calibration procedure is designed to compute those parameters of camera and calculate calibration errors. High-accurate profile extraction algorithm and a checkboard with 48 corners have also been used in this part. Finally, results of calibration program are presented, demonstrating the high efficiency and accuracy of the proposed approach. The results can reach the requirement of robot binocular stereo vision.

  7. High speed vision processor with reconfigurable processing element array based on full-custom distributed memory

    Science.gov (United States)

    Chen, Zhe; Yang, Jie; Shi, Cong; Qin, Qi; Liu, Liyuan; Wu, Nanjian

    2016-04-01

    In this paper, a hybrid vision processor based on a compact full-custom distributed memory for near-sensor high-speed image processing is proposed. The proposed processor consists of a reconfigurable processing element (PE) array, a row processor (RP) array, and a dual-core microprocessor. The PE array includes two-dimensional processing elements with a compact full-custom distributed memory. It supports real-time reconfiguration between the PE array and the self-organized map (SOM) neural network. The vision processor is fabricated using a 0.18 µm CMOS technology. The circuit area of the distributed memory is reduced markedly into 1/3 of that of the conventional memory so that the circuit area of the vision processor is reduced by 44.2%. Experimental results demonstrate that the proposed design achieves correct functions.

  8. Vision-Based Semantic Unscented FastSLAM for Indoor Service Robot

    Directory of Open Access Journals (Sweden)

    Xiaorui Zhu

    2015-01-01

    Full Text Available This paper proposes a vision-based Semantic Unscented FastSLAM (UFastSLAM algorithm for mobile service robot combining the semantic relationship and the Unscented FastSLAM. The landmark positions and the semantic relationships among landmarks are detected by a binocular vision. Then the semantic observation model can be created by transforming the semantic relationships into the semantic metric map. Semantic Unscented FastSLAM can be used to update the locations of the landmarks and robot pose even when the encoder inherits large cumulative errors that may not be corrected by the loop closure detection of the vision system. Experiments have been carried out to demonstrate that the Semantic Unscented FastSLAM algorithm can achieve much better performance in indoor autonomous surveillance than Unscented FastSLAM.

  9. Machine vision-based high-resolution weed mapping and patch-sprayer performance simulation

    NARCIS (Netherlands)

    Tang, L.; Tian, L.F.; Steward, B.L.

    1999-01-01

    An experimental machine vision-based patch-sprayer was developed. This sprayer was primarily designed to do real-time weed density estimation and variable herbicide application rate control. However, the sprayer also had the capability to do high-resolution weed mapping if proper mapping techniques

  10. Rationale, Design and Implementation of a Computer Vision-Based Interactive E-Learning System

    Science.gov (United States)

    Xu, Richard Y. D.; Jin, Jesse S.

    2007-01-01

    This article presents a schematic application of computer vision technologies to e-learning that is synchronous, peer-to-peer-based, and supports an instructor's interaction with non-computer teaching equipments. The article first discusses the importance of these focused e-learning areas, where the properties include accurate bidirectional…

  11. Advancement of vision-based SLAM from static to dynamic environments

    CSIR Research Space (South Africa)

    Pancham, A

    2012-11-01

    Full Text Available be not be included in the SLAM map as they may lead to localization errors and reduce map quality. Recent years, have seen the advancement of vision-based SLAM from static to dynamic environments, where SLAM coupled with Detection And Tracking of Moving Objects...

  12. Real-time vision-based detection of Rumex obtusifolius in grassland

    NARCIS (Netherlands)

    Evert, van F.K.; Polder, G.; Heijden, van der G.W.A.M.; Kempenaar, C.; Lotz, L.A.P.

    2009-01-01

    Rumex obtusifolius is a common grassland weed that is hard to control in a non-chemical way. The objective of our research was to automate the detection of R. obtusifolius as a step towards fully automated mechanical control of the weed. We have developed a vision-based system that uses textural ana

  13. A Corpus-Based Discourse Analysis of the Vision and Mission Statements of Universities in Turkey

    Science.gov (United States)

    Efe, Ibrahim; Ozer, Omer

    2015-01-01

    This article presents findings from a corpus-assisted discourse analysis of mission and vision statements of 105 state and 66 private/foundation universities in Turkey. The paper combines a corpus-based approach with critical discourse analysis to interpret the data in relation to its institutional as well as socio-political context. It argues…

  14. Real-time vision-based detection of Rumex obtusifolius in grassland

    NARCIS (Netherlands)

    Evert, van F.K.; Polder, G.; Heijden, van der G.W.A.M.; Kempenaar, C.; Lotz, L.A.P.

    2009-01-01

    Rumex obtusifolius is a common grassland weed that is hard to control in a non-chemical way. The objective of our research was to automate the detection of R. obtusifolius as a step towards fully automated mechanical control of the weed. We have developed a vision-based system that uses textural ana

  15. Rationale, Design and Implementation of a Computer Vision-Based Interactive E-Learning System

    Science.gov (United States)

    Xu, Richard Y. D.; Jin, Jesse S.

    2007-01-01

    This article presents a schematic application of computer vision technologies to e-learning that is synchronous, peer-to-peer-based, and supports an instructor's interaction with non-computer teaching equipments. The article first discusses the importance of these focused e-learning areas, where the properties include accurate bidirectional…

  16. Robotics Vision-based Heuristic Reasoning for Underwater Target Tracking and Navigation

    Directory of Open Access Journals (Sweden)

    Chua Kia

    2008-11-01

    Full Text Available This paper presents a robotics vision-based heuristic reasoning system for underwater target tracking and navigation. This system is introduced to improve the level of automation of underwater Remote Operated Vehicles (ROVs operations. A prototype which combines computer vision with an underwater robotics system is successfully designed and developed to perform target tracking and intelligent navigation. This study focuses on developing image processing algorithms and fuzzy inference system for the analysis of the terrain. The vision system developed is capable of interpreting underwater scene by extracting subjective uncertainties of the object of interest. Subjective uncertainties are further processed as multiple inputs of a fuzzy inference system that is capable of making crisp decisions concerning where to navigate. The important part of the image analysis is morphological filtering. The applications focus on binary images with the extension of gray-level concepts. An open-loop fuzzy control system is developed for classifying the traverse of terrain. The great achievement is the system's capability to recognize and perform target tracking of the object of interest (pipeline in perspective view based on perceived condition. The effectiveness of this approach is demonstrated by computer and prototype simulations. This work is originated from the desire to develop robotics vision system with the ability to mimic the human expert's judgement and reasoning when maneuvering ROV in the traverse of the underwater terrain.

  17. Novel compact panomorph lens based vision system for monitoring around a vehicle

    Science.gov (United States)

    Thibault, Simon

    2008-04-01

    Automotive applications are one of the largest vision-sensor market segments and one of the fastest growing ones. The trend to use increasingly more sensors in cars is driven both by legislation and consumer demands for higher safety and better driving experiences. Awareness of what directly surrounds a vehicle affects safe driving and manoeuvring of a vehicle. Consequently, panoramic 360° Field of View imaging can contributes most to the perception of the world around the driver than any other sensors. However, to obtain a complete vision around the car, several sensor systems are necessary. To solve this issue, a customized imaging system based on a panomorph lens will provide the maximum information for the drivers with a reduced number of sensors. A panomorph lens is a hemispheric wide angle anamorphic lens with enhanced resolution in predefined zone of interest. Because panomorph lenses are optimized to a custom angle-to-pixel relationship, vision systems provide ideal image coverage that reduces and optimizes the processing. We present various scenarios which may benefit from the use of a custom panoramic sensor. We also discuss the technical requirements of such vision system. Finally we demonstrate how the panomorph based visual sensor is probably one of the most promising ways to fuse many sensors in one. For example, a single panoramic sensor on the front of a vehicle could provide all necessary information for assistance in crash avoidance, lane tracking, early warning, park aids, road sign detection, and various video monitoring views.

  18. Novel applications of hyperstereo vision

    Science.gov (United States)

    Watkins, Wendell R.; Jordan, Jay B.; Trivedi, Mohan M.

    1997-09-01

    Recent stereo vision experiments show potential in enhancing vehicular navigation, target acquisition, and optical turbulence mitigation. The experiments involved the use of stereo vision headsets connected to visible and 8-12 micrometers IR imagers. The imagers were separated by up to 50 m and equipped with telescopes for viewing at ranges of tens of meters up to 4 km. The important findings were: (1) human viewers were able to discern terrain undulations for obstacle avoidance, (2) human viewers were able to detect depth features within the scenes that enhanced the target acquisition process over using monocular viewing,and (3) human viewers noted appreciable reduction in the distortion effects of optical turbulence over that observed through a single monocular channel. For navigation, stereo goggles were developed for headset display and simultaneous direct vision for vehicular navigation enhancement. For detection, the depth cues can be used to detect even salient target features. For optical turbulence, the human mechanisms of fusing two views into a single perceived scene can be used to provide nearly undistorted perception. These experiments show significant improvement for many applications.

  19. Effect of monocular deprivation on rabbit neural retinal cell densities

    Directory of Open Access Journals (Sweden)

    Philip Maseghe Mwachaka

    2015-01-01

    Conclusion: In this rabbit model, monocular deprivation resulted in activity-dependent changes in cell densities of the neural retina in favour of the non-deprived eye along with reduced cell densities in the deprived eye.

  20. Computationally Efficient Iterative Pose Estimation for Space Robot Based on Vision

    Directory of Open Access Journals (Sweden)

    Xiang Wu

    2013-01-01

    Full Text Available In postestimation problem for space robot, photogrammetry has been used to determine the relative pose between an object and a camera. The calculation of the projection from two-dimensional measured data to three-dimensional models is of utmost importance in this vision-based estimation however, this process is usually time consuming, especially in the outer space environment with limited performance of hardware. This paper proposes a computationally efficient iterative algorithm for pose estimation based on vision technology. In this method, an error function is designed to estimate the object-space collinearity error, and the error is minimized iteratively for rotation matrix based on the absolute orientation information. Experimental result shows that this approach achieves comparable accuracy with the SVD-based methods; however, the computational time has been greatly reduced due to the use of the absolute orientation method.

  1. Motion Detection in the Far Peripheral Vision Field

    Science.gov (United States)

    2007-12-01

    responsible for the human ability to appreciate spatial detail (visual acuity), discriminate color, stereopsis , and other fine discrimina- tions, and...Visual-vestibular interactions: I. Influence of peripheral vision on suppression of the vestibulo-ocular reflex and visual acuity. Aviat Space...2403–2411. 45, Kochhar, D. S.; Fraser, T. M. Monocular peripheral vision as a factor in flight safety aviation . Space, and Environmental Medicine

  2. Should Family and Friends Be Involved in Group-Based Rehabilitation Programs for Adults with Low Vision?

    Science.gov (United States)

    Rees, G.; Saw, C.; Larizza, M.; Lamoureux, E.; Keeffe, J.

    2007-01-01

    This qualitative study investigates the views of clients with low vision and vision rehabilitation professionals on the involvement of family and friends in group-based rehabilitation programs. Both groups outlined advantages and disadvantages to involving significant others, and it is essential that clients are given the choice. Future work is…

  3. Optical study on the vision correction and supernormal vision based on the wave-front aberrations of human eye

    Institute of Scientific and Technical Information of China (English)

    MU GuoGuang; WANG ZhaoQi; LIU YongJi; QUAN Wei; WANG Yang; WANG Wei

    2007-01-01

    In this paper we present the recent research results in the field of vision correction and supernormal vision according to the actual measurements of the wave-front aberrations and the corneal surface topography, the clinical detection of the visual function and the laser corneal refractive surgery, and the optimization of the optical system. These include the features of the aberrations of human eye with different pupil sizes, different fields of view and temporal accommodation, the influence of the polychromatic illumination of the visible wavelength on the supernormal vision,and the effect of the existing laser corneal refractive surgery on the wave-front aberrations of the eye. It is shown that the wave-front aberration of human eye is of temporal variation and of synthesis with multi impact factors. To achieve supernormal vision, an optimum engineering data for the customized laser corneal surgery should be firstly acquired, which may involve the dynamic free-form optical surface. Although the myopia can be corrected by the laser in situ keratomileusis (LASlK) in a certain degree, it brings about negative effects under scotopic conditions.

  4. Optical study on the vision correction and supernormal vision based on the wave-front aberrations of human eye

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper we present the recent research results in the field of vision correction and supernormal vision according to the actual measurements of the wave-front aberrations and the corneal surface topography,the clinical detection of the visual function and the laser corneal refractive surgery,and the optimization of the optical system. These include the features of the aberrations of human eye with different pupil sizes,different fields of view and temporal accommodation,the influence of the polychromatic illumination of the visible wavelength on the supernormal vision,and the effect of the existing laser corneal refractive surgery on the wave-front ab-errations of the eye. It is shown that the wave-front aberration of human eye is of temporal variation and of synthesis with multi impact factors. To achieve super-normal vision,an optimum engineering data for the customized laser corneal sur-gery should be firstly acquired,which may involve the dynamic free-form optical surface. Although the myopia can be corrected by the laser in situ keratomileusis(LASIK) in a certain degree,it brings about negative effects under scotopic condi-tions.

  5. Pose Self-Measurement of Noncooperative Spacecraft Based on Solar Panel Triangle Structure

    OpenAIRE

    Jingzhou Song; Caixiu Cao

    2015-01-01

    Aiming at the recognition and location of noncooperative spacecraft, this paper presents a monocular vision pose measurement method based on solar triangle structure. First of all, an autonomous recognition algorithm of feature structure based on sliding window Hough transformation (SWHT) and inscribed circle of a triangle is proposed, and the image coordinates of feature points on the triangle can be obtained relying on this algorithm, combined with the P4P algorithm and the structure of spa...

  6. Vision-based localization for on-orbit servicing of a partially cooperative satellite

    Science.gov (United States)

    Oumer, Nassir W.; Panin, Giorgio; Mülbauer, Quirin; Tseneklidou, Anastasia

    2015-12-01

    This paper proposes ground-in-the-loop, model-based visual localization system based on transmitted images to ground, to aid rendezvous and docking maneuvers between a servicer and a target satellite. In particular, we assume to deal with a partially cooperative target, i.e. passive and without fiducial markers, but supposed at least to keep a controlled attitude, up to small fluctuations, so that the approach mainly involves translational motion. For the purpose of localization, video cameras provide an effective and relatively inexpensive solution, working at a wide range of distances with an increasing accuracy and robustness during the approach. However, illumination conditions in space are especially challenging, due to the direct sunlight exposure and to the glossy surface of a satellite, that creates strong reflections and saturations and therefore a high level of background clutter and missing detections. We employ a monocular camera for mid-range tracking (20 - 5 m) and stereo camera at close-range (5 - 0.5 m), with the respective detection and tracking methods, both using intensity edges and robustly dealing with the above issues. Our tracking system has been extensively verified at the facility of the European Proximity Operations Simulator (EPOS) of DLR, which is a very realistic ground simulation able to reproduce sunlight conditions through a high power floodlight source, satellite surface properties using multilayer insulation foils, as well as orbital motion trajectories with ground-truth data, by means of two 6 DOF industrial robots. Results from this large dataset show the effectiveness and robustness of our method against the above difficulties.

  7. Localization of monocular stimuli in different depth planes.

    Science.gov (United States)

    Shimono, Koichi; Tam, Wa James; Asakura, Nobuhiko; Ohmi, Masao

    2005-09-01

    We examined the phenomenon in which two physically aligned monocular stimuli appear to be non-collinear when each of them is located in binocular regions that are at different depth planes. Using monocular bars embedded in binocular random-dot areas that are at different depths, we manipulated properties of the binocular areas and examined their effect on the perceived direction and depth of the monocular stimuli. Results showed that (1) the relative visual direction and perceived depth of the monocular bars depended on the binocular disparity and the dot density of the binocular areas, and (2) the visual direction, but not the depth, depended on the width of the binocular regions. These results are consistent with the hypothesis that monocular stimuli are treated by the visual system as binocular stimuli that have acquired the properties of their binocular surrounds. Moreover, partial correlation analysis suggests that the visual system utilizes both the disparity information of the binocular areas and the perceived depth of the monocular bars in determining the relative visual direction of the bars.

  8. A Vision-Based Approach for Estimating Contact Forces: Applications to Robot-Assisted Surgery

    Directory of Open Access Journals (Sweden)

    C. W. Kennedy

    2005-01-01

    Full Text Available The primary goal of this paper is to provide force feedback to the user using vision-based techniques. The approach presented in this paper can be used to provide force feedback to the surgeon for robot-assisted procedures. As proof of concept, we have developed a linear elastic finite element model (FEM of a rubber membrane whereby the nodal displacements of the membrane points are measured using vision. These nodal displacements are the input into our finite element model. In the first experiment, we track the deformation of the membrane in real-time through stereovision and compare it with the actual deformation computed through forward kinematics of the robot arm. On the basis of accurate deformation estimation through vision, we test the physical model of a membrane developed through finite element techniques. The FEM model accurately reflects the interaction forces on the user console when the interaction forces of the robot arm with the membrane are compared with those experienced by the surgeon on the console through the force feedback device. In the second experiment, the PHANToM haptic interface device is used to control the Mitsubishi PA-10 robot arm and interact with the membrane in real-time. Image data obtained through vision of the deformation of the membrane is used as the displacement input for the FEM model to compute the local interaction forces which are then displayed on the user console for providing force feedback and hence closing the loop.

  9. Intelligent Machine Vision Based Modeling and Positioning System in Sand Casting Process

    Directory of Open Access Journals (Sweden)

    Shahid Ikramullah Butt

    2017-01-01

    Full Text Available Advanced vision solutions enable manufacturers in the technology sector to reconcile both competitive and regulatory concerns and address the need for immaculate fault detection and quality assurance. The modern manufacturing has completely shifted from the manual inspections to the machine assisted vision inspection methodology. Furthermore, the research outcomes in industrial automation have revolutionized the whole product development strategy. The purpose of this research paper is to introduce a new scheme of automation in the sand casting process by means of machine vision based technology for mold positioning. Automation has been achieved by developing a novel system in which casting molds of different sizes, having different pouring cup location and radius, position themselves in front of the induction furnace such that the center of pouring cup comes directly beneath the pouring point of furnace. The coordinates of the center of pouring cup are found by using computer vision algorithms. The output is then transferred to a microcontroller which controls the alignment mechanism on which the mold is placed at the optimum location.

  10. Flexible Wing Base Micro Aerial Vehicles: Towards Flight Autonomy: Vision-Based Horizon Detection for Micro Air Vehicles

    Science.gov (United States)

    Nechyba, Michael C.; Ettinger, Scott M.; Ifju, Peter G.; Wazak, Martin

    2002-01-01

    Recently substantial progress has been made towards design building and testifying remotely piloted Micro Air Vehicles (MAVs). This progress in overcoming the aerodynamic obstacles to flight at very small scales has, unfortunately, not been matched by similar progress in autonomous MAV flight. Thus, we propose a robust, vision-based horizon detection algorithm as the first step towards autonomous MAVs. In this paper, we first motivate the use of computer vision for the horizon detection task by examining the flight of birds (biological MAVs) and considering other practical factors. We then describe our vision-based horizon detection algorithm, which has been demonstrated at 30 Hz with over 99.9% correct horizon identification, over terrain that includes roads, buildings large and small, meadows, wooded areas, and a lake. We conclude with some sample horizon detection results and preview a companion paper, where the work discussed here forms the core of a complete autonomous flight stability system.

  11. Vision-based Recognition of Activities by a Humanoid Robot

    Directory of Open Access Journals (Sweden)

    Mounîm A. El-Yacoubi

    2015-12-01

    Full Text Available We present an autonomous assistive robotic system for human activity recognition from video sequences. Due to the large variability inherent to video capture from a non-fixed robot (as opposed to a fixed camera, as well as the robot’s limited computing resources, implementation has been guided by robustness to this variability and by memory and computing speed efficiency. To accommodate motion speed variability across users, we encode motion using dense interest point trajectories. Our recognition model harnesses the dense interest point bag-of-words representation through an intersection kernel-based SVM that better accommodates the large intra-class variability stemming from a robot operating in different locations and conditions. To contextually assess the engine as implemented in the robot, we compare it with the most recent approaches of human action recognition performed on public datasets (non-robot-based, including a novel approach of our own that is based on a two-layer SVM-hidden conditional random field sequential recognition model. The latter’s performance is among the best within the recent state of the art. We show that our robot-based recognition engine, while less accurate than the sequential model, nonetheless shows good performances, especially given the adverse test conditions of the robot, relative to those of a fixed camera.

  12. The use of computer vision techniques to augment home based sensorised environments.

    Science.gov (United States)

    Uhríková, Zdenka; Nugent, Chris D; Hlavác, Václav

    2008-01-01

    Technology within the home environment is becoming widely accepted as a means to facilitate independent living. Nevertheless, practical issues of detecting different tasks between multiple persons within the same environment along with managing instances of uncertainty associated with recorded sensor data are two key challenges yet to be fully solved. This work presents details of how computer vision techniques can be used as both alternative and complementary means in the assessment of behaviour in home based sensorised environments. Within our work we assessed the ability of vision processing techniques in conjunction with sensor based data to deal with instances of multiple occupancy. Our Results indicate that the inclusion of the video data improved the overall process of task identification by detecting and recognizing multiple people in the environment using color based tracking algorithm.

  13. Region Based Route Planning: Multi-Abstraction Route Planning Based On Intermediate Level Vision Processing

    Science.gov (United States)

    Doshi, Rajkumar S.; Lam, Raymond; White, James E.

    1989-01-01

    The Region Based Route Planner performs intermediate-level and high-level processing on vision data to organize the image into more meaningful higher-level topological representations. A variety of representations are employed at appropriate stages in the route plan-ning process. A variety of abstractions are used for the purposes of problem reduction and application of multiple criteria at different phases during the navigation planning process. The Region Based Route Planner operates in terrain scenarios where some or most of the terrain is occluded. The Region Based Route Planner operates without any priori maps. The route planner uses two dimensional representations and utilizes gradient and roughness information. The implementation described here is being tested on the JPL Robotic Vehicle. The Region Based Route Planner operates in two phases. In the first phase, the terrain map is segmented to derive global information about various features in it. The next phase is the actual route planning phase. The route is planned with increasing amounts of detail by successive refinement. This phase has three abstrac-tions. In the first abstraction, the planner analyses high level information and so a coarse, region-to-region plan is produced. The second abstraction produces a list of pairs of entry and exit waypoints for only these selected regions. In the last abstraction, for every pair of these waypoints, a local route planner is invoked. This planner finds a detailed point-to-point path by searching only within the boundaries of these relatively small regions.

  14. Linear filtering of images based on properties of vision.

    Science.gov (United States)

    Algazi, V R; Ford, G E; Chen, H

    1995-01-01

    The design of linear image filters based on properties of human visual perception has been shown to require the minimization of criterion functions in both the spatial and frequency domains. We extend this approach to continuous filters of infinite support. For lowpass filters, this leads to the concept of an ideal lowpass image filter that provides a response that is superior perceptually to that of the classical ideal lowpass filter.

  15. Vision-based reinforcement learning using approximate policy iteration

    OpenAIRE

    2009-01-01

    A major issue for reinforcement learning (RL) applied to robotics is the time required to learn a new skill. While RL has been used to learn mobile robot control in many simulated domains, applications involving learning on real robots are still relatively rare. In this paper, the Least-Squares Policy Iteration (LSPI) reinforcement learning algorithm and a new model-based algorithm Least-Squares Policy Iteration with Prioritized Sweeping (LSPI+), are implemented on a mobile robot to acquir...

  16. Robust object tracking techniques for vision-based 3D motion analysis applications

    Science.gov (United States)

    Knyaz, Vladimir A.; Zheltov, Sergey Y.; Vishnyakov, Boris V.

    2016-04-01

    Automated and accurate spatial motion capturing of an object is necessary for a wide variety of applications including industry and science, virtual reality and movie, medicine and sports. For the most part of applications a reliability and an accuracy of the data obtained as well as convenience for a user are the main characteristics defining the quality of the motion capture system. Among the existing systems for 3D data acquisition, based on different physical principles (accelerometry, magnetometry, time-of-flight, vision-based), optical motion capture systems have a set of advantages such as high speed of acquisition, potential for high accuracy and automation based on advanced image processing algorithms. For vision-based motion capture accurate and robust object features detecting and tracking through the video sequence are the key elements along with a level of automation of capturing process. So for providing high accuracy of obtained spatial data the developed vision-based motion capture system "Mosca" is based on photogrammetric principles of 3D measurements and supports high speed image acquisition in synchronized mode. It includes from 2 to 4 technical vision cameras for capturing video sequences of object motion. The original camera calibration and external orientation procedures provide the basis for high accuracy of 3D measurements. A set of algorithms as for detecting, identifying and tracking of similar targets, so for marker-less object motion capture is developed and tested. The results of algorithms' evaluation show high robustness and high reliability for various motion analysis tasks in technical and biomechanics applications.

  17. Fast vision through frameless event-based sensing and convolutional processing: application to texture recognition.

    Science.gov (United States)

    Perez-Carrasco, Jose Antonio; Acha, Begona; Serrano, Carmen; Camunas-Mesa, Luis; Serrano-Gotarredona, Teresa; Linares-Barranco, Bernabe

    2010-04-01

    Address-event representation (AER) is an emergent hardware technology which shows a high potential for providing in the near future a solid technological substrate for emulating brain-like processing structures. When used for vision, AER sensors and processors are not restricted to capturing and processing still image frames, as in commercial frame-based video technology, but sense and process visual information in a pixel-level event-based frameless manner. As a result, vision processing is practically simultaneous to vision sensing, since there is no need to wait for sensing full frames. Also, only meaningful information is sensed, communicated, and processed. Of special interest for brain-like vision processing are some already reported AER convolutional chips, which have revealed a very high computational throughput as well as the possibility of assembling large convolutional neural networks in a modular fashion. It is expected that in a near future we may witness the appearance of large scale convolutional neural networks with hundreds or thousands of individual modules. In the meantime, some research is needed to investigate how to assemble and configure such large scale convolutional networks for specific applications. In this paper, we analyze AER spiking convolutional neural networks for texture recognition hardware applications. Based on the performance figures of already available individual AER convolution chips, we emulate large scale networks using a custom made event-based behavioral simulator. We have developed a new event-based processing architecture that emulates with AER hardware Manjunath's frame-based feature recognition software algorithm, and have analyzed its performance using our behavioral simulator. Recognition rate performance is not degraded. However, regarding speed, we show that recognition can be achieved before an equivalent frame is fully sensed and transmitted.

  18. Vision-based adaptive cruise control using pattern matching

    CSIR Research Space (South Africa)

    Kanjee, R

    2013-10-01

    Full Text Available -vehicle system was modelled and tested. All vehicle parameters were estimated based on actual physical characteristics and performance of the University of Johannesburg’s hybrid electric vehicle. A. Modelling the Vehicle The vehicle model used is derived from... input generated by the control system does not directly induce a traction force on the car tires. In an electric vehicle, the throttle position is processed by the engine controller and is mapped proportionally to the motor’s angular velocity. For our...

  19. A vision-based approach for tramway rail extraction

    Science.gov (United States)

    Zwemer, Matthijs H.; van de Wouw, Dennis W. J. M.; Jaspers, Egbert; Zinger, Sveta; de With, Peter H. N.

    2015-03-01

    The growing traffic density in cities fuels the desire for collision assessment systems on public transportation. For this application, video analysis is broadly accepted as a cornerstone. For trams, the localization of tramway tracks is an essential ingredient of such a system, in order to estimate a safety margin for crossing traffic participants. Tramway-track detection is a challenging task due to the urban environment with clutter, sharp curves and occlusions of the track. In this paper, we present a novel and generic system to detect the tramway track in advance of the tram position. The system incorporates an inverse perspective mapping and a-priori geometry knowledge of the rails to find possible track segments. The contribution of this paper involves the creation of a new track reconstruction algorithm which is based on graph theory. To this end, we define track segments as vertices in a graph, in which edges represent feasible connections. This graph is then converted to a max-cost arborescence graph, and the best path is selected according to its location and additional temporal information based on a maximum a-posteriori estimate. The proposed system clearly outperforms a railway-track detector. Furthermore, the system performance is validated on 3,600 manually annotated frames. The obtained results are promising, where straight tracks are found in more than 90% of the images and complete curves are still detected in 35% of the cases.

  20. The Obstacle Detection and Measurement Based on Machine Vision

    Directory of Open Access Journals (Sweden)

    Xitao Zheng

    2010-12-01

    Full Text Available To develop a quick obstacle detection and measurement algorithm for the image-based autonomous vehicle (AV or computer assisted driving system, this paper utilize the previous work of object detection to get the position of an obstacle and refocus windows on the selected target. Further calculation based on single camera will give the detailed measurement of the object, like the height, the distance to the vehicle, and possibly the width. It adopts a two camera system with different pitch angles, which can perform real-time monitoring for the front area of the vehicle with different coverage. This paper assumes that the vehicle will move at an even speed on a flat road, cameras will sample images at a given rate and the images will be analyzed simultaneously. Focus will be on the virtual window area of the image which is proved to be related to the distance to the object and speed of the vehicle. Counting of the blackened virtual sub-area can quickly find the existence of an obstacle and the obstacle area will be cut to get the interested parameter measurements for the object evaluation.

  1. Improvements in clinical and functional vision and perceived visual disability after first and second eye cataract surgery

    OpenAIRE

    Elliott, D; Patla, A.; Bullimore, M.

    1997-01-01

    AIMS—To determine the improvements in clinical and functional vision and perceived visual disability after first and second eye cataract surgery.
METHODS—Clinical vision (monocular and binocular high and low contrast visual acuity, contrast sensitivity, and disability glare), functional vision (face identity and expression recognition, reading speed, word acuity, and mobility orientation), and perceived visual disability (Activities of Daily Vision Scale) were measured in 25 subjects before a...

  2. Machine Vision-Based Measurement Systems for Fruit and Vegetable Quality Control in Postharvest.

    Science.gov (United States)

    Blasco, José; Munera, Sandra; Aleixos, Nuria; Cubero, Sergio; Molto, Enrique

    2017-03-14

    Individual items of any agricultural commodity are different from each other in terms of colour, shape or size. Furthermore, as they are living thing, they change their quality attributes over time, thereby making the development of accurate automatic inspection machines a challenging task. Machine vision-based systems and new optical technologies make it feasible to create non-destructive control and monitoring tools for quality assessment to ensure adequate accomplishment of food standards. Such systems are much faster than any manual non-destructive examination of fruit and vegetable quality, thus allowing the whole production to be inspected with objective and repeatable criteria. Moreover, current technology makes it possible to inspect the fruit in spectral ranges beyond the sensibility of the human eye, for instance in the ultraviolet and near-infrared regions. Machine vision-based applications require the use of multiple technologies and knowledge, ranging from those related to image acquisition (illumination, cameras, etc.) to the development of algorithms for spectral image analysis. Machine vision-based systems for inspecting fruit and vegetables are targeted towards different purposes, from in-line sorting into commercial categories to the detection of contaminants or the distribution of specific chemical compounds on the product's surface. This chapter summarises the current state of the art in these techniques, starting with systems based on colour images for the inspection of conventional colour, shape or external defects and then goes on to consider recent developments in spectral image analysis for internal quality assessment or contaminant detection.

  3. A vision-free brain-computer interface (BCI) paradigm based on auditory selective attention.

    Science.gov (United States)

    Kim, Do-Won; Cho, Jae-Hyun; Hwang, Han-Jeong; Lim, Jeong-Hwan; Im, Chang-Hwan

    2011-01-01

    Majority of the recently developed brain computer interface (BCI) systems have been using visual stimuli or visual feedbacks. However, the BCI paradigms based on visual perception might not be applicable to severe locked-in patients who have lost their ability to control their eye movement or even their vision. In the present study, we investigated the feasibility of a vision-free BCI paradigm based on auditory selective attention. We used the power difference of auditory steady-state responses (ASSRs) when the participant modulates his/her attention to the target auditory stimulus. The auditory stimuli were constructed as two pure-tone burst trains with different beat frequencies (37 and 43 Hz) which were generated simultaneously from two speakers located at different positions (left and right). Our experimental results showed high classification accuracies (64.67%, 30 commands/min, information transfer rate (ITR) = 1.89 bits/min; 74.00%, 12 commands/min, ITR = 2.08 bits/min; 82.00%, 6 commands/min, ITR = 1.92 bits/min; 84.33%, 3 commands/min, ITR = 1.12 bits/min; without any artifact rejection, inter-trial interval = 6 sec), enough to be used for a binary decision. Based on the suggested paradigm, we implemented a first online ASSR-based BCI system that demonstrated the possibility of materializing a totally vision-free BCI system.

  4. Computer vision-based limestone rock-type classification using probabilistic neural network

    Institute of Scientific and Technical Information of China (English)

    Ashok Kumar Patel; Snehamoy Chatterjee

    2016-01-01

    Proper quality planning of limestone raw materials is an essential job of maintaining desired feed in cement plant. Rock-type identification is an integrated part of quality planning for limestone mine. In this paper, a computer vision-based rock-type classification algorithm is proposed for fast and reliable identification without human intervention. A laboratory scale vision-based model was developed using probabilistic neural network (PNN) where color histogram features are used as input. The color image histogram-based features that include weighted mean, skewness and kurtosis features are extracted for all three color space red, green, and blue. A total nine features are used as input for the PNN classification model. The smoothing parameter for PNN model is selected judicially to develop an optimal or close to the optimum classification model. The developed PPN is validated using the test data set and results reveal that the proposed vision-based model can perform satisfactorily for classifying limestone rock-types. Overall the error of mis-classification is below 6%. When compared with other three classifica-tion algorithms, it is observed that the proposed method performs substantially better than all three classification algorithms.

  5. Computer vision-based limestone rock-type classification using probabilistic neural network

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Patel

    2016-01-01

    Full Text Available Proper quality planning of limestone raw materials is an essential job of maintaining desired feed in cement plant. Rock-type identification is an integrated part of quality planning for limestone mine. In this paper, a computer vision-based rock-type classification algorithm is proposed for fast and reliable identification without human intervention. A laboratory scale vision-based model was developed using probabilistic neural network (PNN where color histogram features are used as input. The color image histogram-based features that include weighted mean, skewness and kurtosis features are extracted for all three color space red, green, and blue. A total nine features are used as input for the PNN classification model. The smoothing parameter for PNN model is selected judicially to develop an optimal or close to the optimum classification model. The developed PPN is validated using the test data set and results reveal that the proposed vision-based model can perform satisfactorily for classifying limestone rock-types. Overall the error of mis-classification is below 6%. When compared with other three classification algorithms, it is observed that the proposed method performs substantially better than all three classification algorithms.

  6. A Vision-Based Emergency Response System with a Paramedic Mobile Robot

    Science.gov (United States)

    Jeong, Il-Woong; Choi, Jin; Cho, Kyusung; Seo, Yong-Ho; Yang, Hyun Seung

    Detecting emergency situation is very important to a surveillance system for people like elderly live alone. A vision-based emergency response system with a paramedic mobile robot is presented in this paper. The proposed system is consisted of a vision-based emergency detection system and a mobile robot as a paramedic. A vision-based emergency detection system detects emergency by tracking people and detecting their actions from image sequences acquired by single surveillance camera. In order to recognize human actions, interest regions are segmented from the background using blob extraction method and tracked continuously using generic model. Then a MHI (Motion History Image) for a tracked person is constructed by silhouette information of region blobs and model actions. Emergency situation is finally detected by applying these information to neural network. When an emergency is detected, a mobile robot can help to diagnose the status of the person in the situation. To send the mobile robot to the proper position, we implement mobile robot navigation algorithm based on the distance between the person and a mobile robot. We validate our system by showing emergency detection rate and emergency response demonstration using the mobile robot.

  7. Bio-Inspired Vision-Based Leader-Follower Formation Flying in the Presence of Delays

    Directory of Open Access Journals (Sweden)

    John Oyekan

    2016-08-01

    Full Text Available Flocking starlings at dusk are known for the mesmerizing and intricate shapes they generate, as well as how fluid these shapes change. They seem to do this effortlessly. Real-life vision-based flocking has not been achieved in micro-UAVs (micro Unmanned Aerial Vehicles to date. Towards this goal, we make three contributions in this paper: (i we used a computational approach to develop a bio-inspired architecture for vision-based Leader-Follower formation flying on two micro-UAVs. We believe that the minimal computational cost of the resulting algorithm makes it suitable for object detection and tracking during high-speed flocking; (ii we show that provided delays in the control loop of a micro-UAV are below a critical value, Kalman filter-based estimation algorithms are not required to achieve Leader-Follower formation flying; (iii unlike previous approaches, we do not use external observers, such as GPS signals or synchronized communication with flock members. These three contributions could be useful in achieving vision-based flocking in GPS-denied environments on computationally-limited agents.

  8. Indoor scene classification of robot vision based on cloud computing

    Science.gov (United States)

    Hu, Tao; Qi, Yuxiao; Li, Shipeng

    2016-07-01

    For intelligent service robots, indoor scene classification is an important issue. To overcome the weak real-time performance of conventional algorithms, a new method based on Cloud computing is proposed for global image features in indoor scene classification. With MapReduce method, global PHOG feature of indoor scene image is extracted in parallel. And, feature eigenvector is used to train the decision classifier through SVM concurrently. Then, the indoor scene is validly classified by decision classifier. To verify the algorithm performance, we carried out an experiment with 350 typical indoor scene images from MIT LabelMe image library. Experimental results show that the proposed algorithm can attain better real-time performance. Generally, it is 1.4 2.1 times faster than traditional classification methods which rely on single computation, while keeping stable classification correct rate as 70%.

  9. Realtime Vision-Based Surface Defect Inspection of Steel Balls

    Institute of Scientific and Technical Information of China (English)

    Wang Zhong; Xing Qian; Fu Luhua; Sun Hong

    2015-01-01

    In the proposed system for online inspection of steel balls, a diffuse illumination is developed to enhance defect appearances and produce high quality images. To fully view the entire sphere, a novel unfolding method is put forward based on geometrical analysis, which only requires one-dimensional movement of the balls and a pair of cam-eras to capture images from different directions. Moreover, a realtime inspection algorithm is customized to improve both accuracy and efficiency. The precision and recall of the sample set were 87.7% and 98%, respectively. The aver-age time cost on image processing and analysis for a steel ballwas 47 ms, and the total time cost was less than 200 ms plus the cost of image acquisition and balls’ movement. The system can sort 18 000 balls per hour with a spatial reso-lution higher than 0.01 mm.

  10. RESEARCH ON SEGMENTATION OF WEED IMAGES BASED ON COMPUTER VISION

    Institute of Scientific and Technical Information of China (English)

    Liu Yajing; Yang Fan; Yang Ruixia; Jia Kejin; Zhang Hongtao

    2007-01-01

    In this letter, a segment algorithm based on color feature of images is proposed. The algorithm separates the weed area from soil background according to the color eigenvalue, which is obtained by analyzing the color difference between the weeds and background in three color spaces RGB, rgb and HSI. The results of the experiment show that it can get notable effect in segmentation according to the color feature, and the possibility of successful segmentation is 87%-93%. This method can also be widely used in other fields which are complicated in the background of the image and facilely influenced in illumination, such as weed identification, tree species discrimination, fruit picking and so on.

  11. Vision based error detection for 3D printing processes

    Directory of Open Access Journals (Sweden)

    Baumann Felix

    2016-01-01

    Full Text Available 3D printers became more popular in the last decade, partly because of the expiration of key patents and the supply of affordable machines. The origin is located in rapid prototyping. With Additive Manufacturing (AM it is possible to create physical objects from 3D model data by layer wise addition of material. Besides professional use for prototyping and low volume manufacturing they are becoming widespread amongst end users starting with the so called Maker Movement. The most prevalent type of consumer grade 3D printers is Fused Deposition Modelling (FDM, also Fused Filament Fabrication FFF. This work focuses on FDM machinery because of their widespread occurrence and large number of open problems like precision and failure. These 3D printers can fail to print objects at a statistical rate depending on the manufacturer and model of the printer. Failures can occur due to misalignment of the print-bed, the print-head, slippage of the motors, warping of the printed material, lack of adhesion or other reasons. The goal of this research is to provide an environment in which these failures can be detected automatically. Direct supervision is inhibited by the recommended placement of FDM printers in separate rooms away from the user due to ventilation issues. The inability to oversee the printing process leads to late or omitted detection of failures. Rejects effect material waste and wasted time thus lowering the utilization of printing resources. Our approach consists of a camera based error detection mechanism that provides a web based interface for remote supervision and early failure detection. Early failure detection can lead to reduced time spent on broken prints, less material wasted and in some cases salvaged objects.

  12. Vision-Based Robot Following Using PID Control

    Directory of Open Access Journals (Sweden)

    Chandra Sekhar Pati

    2017-06-01

    Full Text Available Applications like robots which are employed for shopping, porter services, assistive robotics, etc., require a robot to continuously follow a human or another robot. This paper presents a mobile robot following another tele-operated mobile robot based on a PID (Proportional–Integral-Differential controller. Here, we use two differential wheel drive robots; one is a master robot and the other is a follower robot. The master robot is manually controlled and the follower robot is programmed to follow the master robot. For the master robot, a Bluetooth module receives the user’s command from an android application which is processed by the master robot’s controller, which is used to move the robot. The follower robot receives the image from the Kinect sensor mounted on it and recognizes the master robot. The follower robot identifies the x, y positions by employing the camera and the depth by using the Kinect depth sensor. By identifying the x, y, and z locations of the master robot, the follower robot finds the angle and distance between the master and follower robot, which is given as the error term of a PID controller. Using this, the follower robot follows the master robot. A PID controller is based on feedback and tries to minimize the error. Experiments are conducted for two indigenously developed robots; one depicting a humanoid and the other a small mobile robot. It was observed that the follower robot was easily able to follow the master robot using well-tuned PID parameters.

  13. Visual Enhancement for Sports Entertainment by Vision-Based Augmented Reality

    Directory of Open Access Journals (Sweden)

    Hideo Saito

    2008-09-01

    Full Text Available This paper presents visually enhanced sports entertainment applications: AR Baseball Presentation System and Interactive AR Bowling System. We utilize vision-based augmented reality for getting immersive feeling. First application is an observation system of a virtual baseball game on the tabletop. 3D virtual players are playing a game on a real baseball field model, so that users can observe the game from favorite view points through a handheld monitor with a web camera. Second application is a bowling system which allows users to roll a real ball down a real bowling lane model on the tabletop and knock down virtual pins. The users watch the virtual pins through the monitor. The lane and the ball are also tracked by vision-based tracking. In those applications, we utilize multiple 2D markers distributed at arbitrary positions and directions. Even though the geometrical relationship among the markers is unknown, we can track the camera in very wide area.

  14. Vision based assistive technology for people with dementia performing activities of daily living (ADLs): an overview

    Science.gov (United States)

    As'ari, M. A.; Sheikh, U. U.

    2012-04-01

    The rapid development of intelligent assistive technology for replacing a human caregiver in assisting people with dementia performing activities of daily living (ADLs) promises in the reduction of care cost especially in training and hiring human caregiver. The main problem however, is the various kinds of sensing agents used in such system and is dependent on the intent (types of ADLs) and environment where the activity is performed. In this paper on overview of the potential of computer vision based sensing agent in assistive system and how it can be generalized and be invariant to various kind of ADLs and environment. We find that there exists a gap from the existing vision based human action recognition method in designing such system due to cognitive and physical impairment of people with dementia.

  15. Computer vision-based classification of hand grip variations in neurorehabilitation.

    Science.gov (United States)

    Zariffa, José; Steeves, John D

    2011-01-01

    The complexity of hand function is such that most existing upper limb rehabilitation robotic devices use only simplified hand interfaces. This is in contrast to the importance of the hand in regaining function after neurological injury. Computer vision technology has been used to identify hand posture in the field of Human Computer Interaction, but this approach has not been translated to the rehabilitation context. We describe a computer vision-based classifier that can be used to discriminate rehabilitation-relevant hand postures, and could be integrated into a virtual reality-based upper limb rehabilitation system. The proposed system was tested on a set of video recordings from able-bodied individuals performing cylindrical grasps, lateral key grips, and tip-to-tip pinches. The overall classification success rate was 91.2%, and was above 98% for 6 out of the 10 subjects. © 2011 IEEE

  16. Vision Based Navigation for a Mobile Robot with Different Field of Views

    CERN Document Server

    Khan, Rizwan A; Saeed, Saqib

    2009-01-01

    The basic idea behind evolutionary robotics is to evolve a set of neural controllers for a particular task at hand. It involves use of various input parameters such as infrared sensors, light sensors and vision based methods. This paper aims to explore the evolution of vision based navigation in a mobile robot. It discusses in detail the effect of different field of views for a mobile robot. The individuals have been evolved using different FOV values and the results have been recorded and analyzed.The optimum values for FOV have been proposed after evaluating more than 100 different values. It has been observed that the optimum FOV value requires lesser number of generations for evolution and the mobile robot trained with that particular value is able to navigate well in the environment.

  17. Optic flow-based vision system for autonomous 3D localization and control of small aerial vehicles

    OpenAIRE

    Kendoul, Farid; Fantoni, Isabelle; Nonami, Kenzo

    2009-01-01

    International audience; The problem considered in this paper involves the design of a vision-based autopilot for small and micro Unmanned Aerial Vehicles (UAVs). The proposed autopilot is based on an optic flow-based vision system for autonomous localization and scene mapping, and a nonlinear control system for flight control and guidance. This paper focusses on the development of a real-time 3D vision algorithm for estimating optic flow, aircraft self-motion and depth map, using a low-resolu...

  18. Quad Rotorcraft Control Vision-Based Hovering and Navigation

    CERN Document Server

    García Carrillo, Luis Rodolfo; Lozano, Rogelio; Pégard, Claude

    2013-01-01

    Quad-Rotor Control develops original control methods for the navigation and hovering flight of an autonomous mini-quad-rotor robotic helicopter. These methods use an imaging system and a combination of inertial and altitude sensors to localize and guide the movement of the unmanned aerial vehicle relative to its immediate environment. The history, classification and applications of UAVs are introduced, followed by a description of modelling techniques for quad-rotors and the experimental platform itself. A control strategy for the improvement of attitude stabilization in quad-rotors is then proposed and tested in real-time experiments. The strategy, based on the use of low-cost components and with experimentally-established robustness, avoids drift in the UAV’s angular position by the addition of an internal control loop to each electronic speed controller ensuring that, during hovering flight, all four motors turn at almost the same speed. The quad-rotor’s Euler angles being very close to the origin, oth...

  19. Online tomato sorting based on shape, maturity, size, and surface defects using machine vision

    OpenAIRE

    ARJENAKI, Omid Omidi; MOGHADDAM, Parviz Ahmadi; MOTLAGH, Asad Moddares

    2013-01-01

    Online sorting of tomatoes according to their features is an important postharvest procedure. The purpose of this research was to develop an efficient machine vision-based experimental sorting system for tomatoes. Relevant sorting parameters included shape (oblong and circular), size (small and large), maturity (color), and defects. The variables defining shape, maturity, and size of the tomatoes were eccentricity, average of color components, and 2-D pixel area, respectively. Tomato defects ...

  20. A Survey of Advances in Vision-Based Human Motion Capture and Analysis

    DEFF Research Database (Denmark)

    Moeslund, Thomas B.; Hilton, Adrian; Krüger, Volker

    2006-01-01

    This survey reviews advances in human motion capture and analysis from 2000 to 2006, following a previous survey of papers up to 2000 Human motion capture continues to be an increasingly active research area in computer vision with over 350 publications over this period. A number of significant r...... actions and behavior. This survey reviews recent trends in video based human capture and analysis, as well as discussing open problems for future research to achieve automatic visual analysis of human movement....

  1. 3D Vision Based Landing Control of a Small Scale Autonomous Helicopter

    OpenAIRE

    Zhenyu Yu; Kenzo Nonami; Jinok Shin; Demian Celestino

    2007-01-01

    Autonomous landing is a challenging but important task for Unmanned Aerial Vehicles (UAV) to achieve high level of autonomy. The fundamental requirement for landing is the knowledge of the height above the ground, and a properly designed controller to govern the process. This paper presents our research results in the study of landing an autonomous helicopter. The abovetheground height sensing is based on a 3D vision system. We have designed a simple planefitting method for e...

  2. Vision-based landing of a simulated unmanned aerial vehicle with fast reinforcement learning

    OpenAIRE

    2010-01-01

    Landing is one of the difficult challenges for an unmanned aerial vehicle (UAV). In this paper, we propose a vision-based landing approach for an autonomous UAV using reinforcement learning (RL). The autonomous UAV learns the landing skill from scratch by interacting with the environment. The reinforcement learning algorithm explored and extended in this study is Least-Squares Policy Iteration (LSPI) to gain a fast learning process and a smooth landing trajectory. The proposed approach has...

  3. A Low Cost Vision Based Hybrid Fiducial Mark Tracking Technique for Mobile Industrial Robots

    OpenAIRE

    Mohammed Y Aalsalem; Wazir Zada Khan; Quratul Ain Arshad

    2012-01-01

    The field of robotic vision is developing rapidly. Robots can react intelligently and provide assistance to user activities through sentient computing. Since industrial applications pose complex requirements that cannot be handled by humans, an efficient low cost and robust technique is required for the tracking of mobile industrial robots. The existing sensor based techniques for mobile robot tracking are expensive and complex to deploy, configure and maintain. Also some of them demand dedic...

  4. Using an FPGA-Based Processing Platform in an Industrial Machine Vision System

    OpenAIRE

    King, William E

    1998-01-01

    This thesis describes the development of a commercial machine vision system as a case study for utilizing the Modular Reprogrammable Real-time Processing Hardware (MORRPH) board. The commercial system described in this thesis is based on a prototype system that was developed as a test-bed for developing the necessary concepts and algorithms. The prototype system utilized color linescan cameras, custom framegrabbers, and standard PCs to color-sort red oak parts (staves). When a furniture ma...

  5. Vision-based Nano Robotic System for High-throughput Non-embedded Cell Cutting

    OpenAIRE

    Wanfeng Shang; Haojian Lu; Wenfeng Wan; Toshio Fukuda; Yajing Shen

    2016-01-01

    Cell cutting is a significant task in biology study, but the highly productive non-embedded cell cutting is still a big challenge for current techniques. This paper proposes a vision-based nano robotic system and then realizes automatic non-embedded cell cutting with this system. First, the nano robotic system is developed and integrated with a nanoknife inside an environmental scanning electron microscopy (ESEM). Then, the positions of the nanoknife and the single cell are recognized, and th...

  6. A vision-based path planner/follower for an assistive robotics project

    OpenAIRE

    Cherubini, Andrea; Oriolo, Giuseppe; Macri, Francesco; Aloise, Fabio; Cincotti, Febo; Mattia, Donatella

    2007-01-01

    International audience; Assistive technology is an emerging area where robots can be used to help individuals with motor disabilities achieve independence in daily living activities. Mobile robots should be able to autonomously and safely move in the environment (e.g. the user apartment), by accurately solving the self-localization problem and planning ef paths to the target destination speciied by the user. This paper presents a vision-based navigation scheme designed for Sony AIBO, in ASPIC...

  7. Vision-based threat detection in dynamic environments.

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Jeffrey J.

    2007-08-01

    This report addresses the development of automated video-screening technology to assist security forces in protecting our homeland against terrorist threats. A prevailing threat is the covert placement of bombs inside crowded public facilities. Although video-surveillance systems are increasingly common, current systems cannot detect the placement of bombs. It is also unlikely that security personnel could detect a bomb or its placement by observing video from surveillance cameras. The problems lie in the large number of cameras required to monitor large areas, the limited number of security personnel employed to protect these areas, and the intense diligence required to effectively screen live video from even a single camera. Different from existing video-detection systems designed to operate in nearly static environments, we are developing technology to detect changes in the background of dynamic environments: environments where motion and human activities are persistent over long periods. Our goal is to quickly detect background changes, even if the background is visible to the camera less than 5 percent of the time and possibly never free from foreground activity. Our approach employs statistical scene models based on mixture densities. We hypothesized that the background component of the mixture has a small variance compared to foreground components. Experiments demonstrate this hypothesis is true under a wide variety of operating conditions. A major focus involved the development of robust background estimation techniques that exploit this property. We desire estimation algorithms that can rapidly produce accurate background estimates and detection algorithms that can reliably detect background changes with minimal nuisance alarms. Another goal is to recognize unusual activities or foreground conditions that could signal an attack (e.g., large numbers of running people, people falling to the floor, etc.). Detection of background changes and/or unusual

  8. Robotics Vision-Based System of Autonomous Underwater Vehicle for an Underwater Pipeline Tracker%自主式水下机器人的光视觉管道探测跟踪系统

    Institute of Scientific and Technical Information of China (English)

    曾文静; 徐玉如; 万磊; 张铁栋

    2012-01-01

    The detection and tracking of underwater pipeline based on monocular vision system of AUV(autonomous underwater vehicle) were addressed.An integrated vision system including software and hardware structure was designed.The feature of underwater pipeline image was analyzed and according to that,corresponding pre-processing method was proposed.An improved Hough transforming was advanced to obtain pipeline contour.Pipeline reference zone was estimated to increase the accuracy and decrease the time cost of pipeline tracking.Finally,the system was validated to be effective and feasible through the tank experiments.%研究了自主式水下机器人(AUV)利用单目光视觉系统对水下管道的检测跟踪问题,对实现该方法的各个过程从硬件组成和软件体系结构两方面进行了阐述,从而完成了一整套水下光视觉系统的软、硬件设计.分析了水下管道图像的特点,结合该特点阐述了图像预处理过程,提出了一种改进的Hough变换方法,改善了管道边界的提取效果.同时采用管道参考区域预测方法,提高了管道的检测率以及实时性,并利用水池试验对系统的可行性和有效性进行了验证.

  9. A review of vision-based motion analysis in sport.

    Science.gov (United States)

    Barris, Sian; Button, Chris

    2008-01-01

    Efforts at player motion tracking have traditionally involved a range of data collection techniques from live observation to post-event video analysis where player movement patterns are manually recorded and categorized to determine performance effectiveness. Due to the considerable time required to manually collect and analyse such data, research has tended to focus only on small numbers of players within predefined playing areas. Whilst notational analysis is a convenient, practical and typically inexpensive technique, the validity and reliability of the process can vary depending on a number of factors, including how many observers are used, their experience, and the quality of their viewing perspective. Undoubtedly the application of automated tracking technology to team sports has been hampered because of inadequate video and computational facilities available at sports venues. However, the complex nature of movement inherent to many physical activities also represents a significant hurdle to overcome. Athletes tend to exhibit quick and agile movements, with many unpredictable changes in direction and also frequent collisions with other players. Each of these characteristics of player behaviour violate the assumptions of smooth movement on which computer tracking algorithms are typically based. Systems such as TRAKUS, SoccerMan, TRAKPERFORMANCE, Pfinder and Prozone all provide extrinsic feedback information to coaches and athletes. However, commercial tracking systems still require a fair amount of operator intervention to process the data after capture and are often limited by the restricted capture environments that can be used and the necessity for individuals to wear tracking devices. Whilst some online tracking systems alleviate the requirements of manual tracking, to our knowledge a completely automated system suitable for sports performance is not yet commercially available. Automatic motion tracking has been used successfully in other domains outside

  10. A vision-based system for fast and accurate laser scanning in robot-assisted phonomicrosurgery.

    Science.gov (United States)

    Dagnino, Giulio; Mattos, Leonardo S; Caldwell, Darwin G

    2015-02-01

    Surgical quality in phonomicrosurgery can be improved by open-loop laser control (e.g., high-speed scanning capabilities) with a robust and accurate closed-loop visual servoing systems. A new vision-based system for laser scanning control during robot-assisted phonomicrosurgery was developed and tested. Laser scanning was accomplished with a dual control strategy, which adds a vision-based trajectory correction phase to a fast open-loop laser controller. The system is designed to eliminate open-loop aiming errors caused by system calibration limitations and by the unpredictable topology of real targets. Evaluation of the new system was performed using CO(2) laser cutting trials on artificial targets and ex-vivo tissue. This system produced accuracy values corresponding to pixel resolution even when smoke created by the laser-target interaction clutters the camera view. In realistic test scenarios, trajectory following RMS errors were reduced by almost 80 % with respect to open-loop system performances, reaching mean error values around 30 μ m and maximum observed errors in the order of 60 μ m. A new vision-based laser microsurgical control system was shown to be effective and promising with significant positive potential impact on the safety and quality of laser microsurgeries.

  11. Computer-based and web-based applications for night vision goggle training

    Science.gov (United States)

    Ruffner, John W.; Woodward, Kim G.

    2001-08-01

    Night vision goggles (NVGs) can enhance military and civilian operations at night. With this increased capability comes the requirement to provide suitable training. Results from field experience and accident analyses suggest that problems experienced by NVG users can be attributed to a limited understanding of NVG limitations and to perceptual problems. In addition, there is evidence that NVG skills are perishable and require frequent practice. Format training is available to help users obtain the required knowledge and skills. However, there often is insufficient opportunity to obtain and practice perceptual skills prior to using NVGs in the operational environment. NVG users need early and continued exposure to the night environment across a broad range of visual and operational conditions to develop and maintain the necessary knowledge and perceptual skills. NVG training has consisted of classroom instruction, hands-on training, and simulator training. Advances in computer-based training (CBT) and web-based training (WBT) have made these technologies very appealing as additions to the NVG training mix. This paper discusses our efforts to develop NVG training using multimedia, interactive CBT and WBT for NVG training. We discuss how NVG CBT and WBT can be extended to military and civilian ground, maritime, and aviation NVG training.

  12. Crossing the divide between computer vision and data bases in search of image data bases

    NARCIS (Netherlands)

    M. Worring; A.W.M. Smeulders

    1998-01-01

    Image databases call upon the combined effort of computing vision and database technology to advance beyond exemplary systems. In this paper we charter several areas for mutually beneficial research activities and provide an architectural design to accommodate it.

  13. Short-term monocular deprivation strengthens the patched eye's contribution to binocular combination.

    Science.gov (United States)

    Zhou, Jiawei; Clavagnier, Simon; Hess, Robert F

    2013-04-18

    Binocularity is a fundamental property of primate vision. Ocular dominance describes the perceptual weight given to the inputs from the two eyes in their binocular combination. There is a distribution of sensory dominance within the normal binocular population with most subjects having balanced inputs while some are dominated by the left eye and some by the right eye. Using short-term monocular deprivation, the sensory dominance can be modulated as, under these conditions, the patched eye's contribution is strengthened. We address two questions: Is this strengthening a general effect such that it is seen for different types of sensory processing? And is the strengthening specific to pattern deprivation, or does it also occur for light deprivation? Our results show that the strengthening effect is a general finding involving a number of sensory functions, and it occurs as a result of both pattern and light deprivation.

  14. A review of RGB-LED based mixed-color illumination system for machine vision and microscopy

    Science.gov (United States)

    Hou, Lexin; Wang, Hexin; Xu, Min

    2016-09-01

    The theory and application of RGB-LED based mixed-color illumination system for use in machine vision and optical microscopy systems are presented. For machine vision system, relationship of various color sources and output image sharpness is discussed. From the viewpoint of gray scale images, evaluation and optimization methods of optimal illumination for machine vision are concluded. The image quality under monochromatic and mixed color illumination is compared. For optical microscopy system, demand of light source is introduced and design thoughts of RGB-LED based mixed-color illumination system are concluded. The problems need to be solved in this field are pointed out.

  15. 3D Vision Based Landing Control of a Small Scale Autonomous Helicopter

    Directory of Open Access Journals (Sweden)

    Zhenyu Yu

    2008-11-01

    Full Text Available Autonomous landing is a challenging but important task for Unmanned Aerial Vehicles (UAV to achieve high level of autonomy. The fundamental requirement for landing is the knowledge of the height above the ground, and a properly designed controller to govern the process. This paper presents our research results in the study of landing an autonomous helicopter. The abovetheground height sensing is based on a 3D vision system. We have designed a simple planefitting method for estimating the height over the ground. The method enables vibration free measurement with the camera rigidly attached on the helicopter without using complicated gimbal or active vision mechanism. The estimated height is used by the landing control loop. Considering the ground effect during landing, we have proposed a twostage landing procedure. Two controllers are designed for the two landing stages respectively. The sensing approach and control strategy has been verified in field flight test and has demonstrated satisfactory performance.

  16. Design and Implementation of a Fully Autonomous UAV's Navigator Based on Omni-directional Vision System

    Directory of Open Access Journals (Sweden)

    Seyed Mohammadreza Kasaei

    2011-12-01

    Full Text Available Unmanned Aerial Vehicles (UAVs are the subject of an increasing interest in many applications . UAVs are seeing more widespread use in military, scenic, and civilian sectors in recent years. Autonomy is one of the major advantages of these vehicles. It is then necessary to develop particular sensor in order to provide efficient navigation functions. The helicopter has been stabilized with visual information through the control loop. Omni directional vision can be a useful sensor for this propose. It can be used as the only sensor or as complementary sensor. In this paper , we propose a novel method for path planning on an UAV based on electrical potential .We are using an omni directional vision system for navigating and path planning.

  17. A 3D terrain reconstruction method of stereo vision based quadruped robot navigation system

    Science.gov (United States)

    Ge, Zhuo; Zhu, Ying; Liang, Guanhao

    2017-01-01

    To provide 3D environment information for the quadruped robot autonomous navigation system during walking through rough terrain, based on the stereo vision, a novel 3D terrain reconstruction method is presented. In order to solve the problem that images collected by stereo sensors have large regions with similar grayscale and the problem that image matching is poor at real-time performance, watershed algorithm and fuzzy c-means clustering algorithm are combined for contour extraction. Aiming at the problem of error matching, duel constraint with region matching and pixel matching is established for matching optimization. Using the stereo matching edge pixel pairs, the 3D coordinate algorithm is estimated according to the binocular stereo vision imaging model. Experimental results show that the proposed method can yield high stereo matching ratio and reconstruct 3D scene quickly and efficiently.

  18. An adaptive fuzzy-sliding lateral control strategy of automated vehicles based on vision navigation

    Science.gov (United States)

    Guo, Jinghua; Li, Linhui; Li, Keqiang; Wang, Rongben

    2013-10-01

    Lateral control is considered to be one of the toughest challenges in the development of automated vehicles due to their features of nonlinearities, parametric uncertainties and external disturbances. In order to overcome these difficulties, an adaptive fuzzy-sliding mode control strategy used for lateral control of vision-based automated vehicles is proposed in this paper. First, a vision algorithm is designed to provide accurate location information of vehicle relative to reference path. Then, an adaptive fuzzy-sliding mode lateral controller is proposed to counteract parametric uncertainties and strong nonlinearities, and the asymptotic stability of the closed-loop lateral control system is proven by the Lyapunov theory. Finally, experimental results indicate that the proposed algorithm can achieve favourable tracking performance, and it has strong robustness.

  19. Computer Vision Based Methods for Detection and Measurement of Psychophysiological Indicators

    DEFF Research Database (Denmark)

    Irani, Ramin

    2017-01-01

    expressions show that present facial expression recognition systems are not reliable for recognizing patients’ emotional states especially when they have difficulties with controlling their facial muscles. Regarding future research, the authors believe that the approaches proposed in this thesis may......Recently, computer vision technologies have been used for analysis of human facial video in order to provide a remotely indicator of some crucial psychophysiological parameters such as fatigue, pain, stress and hearthbeat rate. Available contact-based technologies are inconvenient for monitoring...... patients’ physiological signals due to irritating skin and require huge amount of wires to collect and transmitting the signals. While contact-free computer vision techniques not only can be an easy and economical way to overcome this issue, they provide an automatic recognition of the patients’ emotions...

  20. FPGA-Based Multimodal Embedded Sensor System Integrating Low- and Mid-Level Vision

    Directory of Open Access Journals (Sweden)

    Uwe Meyer-Baese

    2011-08-01

    Full Text Available Motion estimation is a low-level vision task that is especially relevant due to its wide range of applications in the real world. Many of the best motion estimation algorithms include some of the features that are found in mammalians, which would demand huge computational resources and therefore are not usually available in real-time. In this paper we present a novel bioinspired sensor based on the synergy between optical flow and orthogonal variant moments. The bioinspired sensor has been designed for Very Large Scale Integration (VLSI using properties of the mammalian cortical motion pathway. This sensor combines low-level primitives (optical flow and image moments in order to produce a mid-level vision abstraction layer. The results are described trough experiments showing the validity of the proposed system and an analysis of the computational resources and performance of the applied algorithms.

  1. Intelligent Storage and Retrieval Systems Based on RFID and Vision in Automated Warehouse

    Directory of Open Access Journals (Sweden)

    Yinghua Xue

    2012-02-01

    Full Text Available The automated warehouse is widely used in different kinds of corporations aiming to improve the storage and retrieval efficiency. In this paper, the robot system with RFID and vision was applied into the design of warehouses. Firstly, the RFID system is used to localize the target roughly and obtain the attributes of the target. Then the onboard vision system is used to recognize and locate the target precisely. Finally, the robot control scheme is designed based on the results of image processing, and the teaching mode and remote mode are used flexibly to assist robot to grasp the target. The combination of these two modes can not only reduce the complexity of robot control, but also can make full use of the results of image processing. Experiments demonstrate the feasibility of the proposed system.

  2. Enhanced Machine Vision System for Ripe Fruit Detection Based on Robotic Harvesting

    Directory of Open Access Journals (Sweden)

    R. Thendral

    2015-04-01

    Full Text Available The proposed work intends to provide an efficient algorithm for the instruction of an automatic robot arm to choose the ripe fruits on the tree. Steps involved in this study are recognizing and locating the ripe fruits from the leaf and branch portions by using an efficient machine vision algorithm. Initially, discrete wavelet transform is used for better preserving of edges and fine details in the given input image. Then RGB, HSV, L*a*b* and YIQ color spaces were studied to segment the ripe fruits from the surrounding objects. Finally, the results showed that ‘I’ component of the YIQ color space has the best criterion for recognizing the fruit from the foliage. The fruit segmentation based on machine vision has an occlusion problem. In this proposed method these problems are also examined.

  3. Gesture recognition based on computer vision and glove sensor for remote working environments

    Energy Technology Data Exchange (ETDEWEB)

    Chien, Sung Il; Kim, In Chul; Baek, Yung Mok; Kim, Dong Su; Jeong, Jee Won; Shin, Kug [Kyungpook National University, Taegu (Korea)

    1998-04-01

    In this research, we defined a gesture set needed for remote monitoring and control of a manless system in atomic power station environments. Here, we define a command as the loci of a gesture. We aim at the development of an algorithm using a vision sensor and glove sensors in order to implement the gesture recognition system. The gesture recognition system based on computer vision tracks a hand by using cross correlation of PDOE image. To recognize the gesture word, the 8 direction code is employed as the input symbol for discrete HMM. Another gesture recognition based on sensor has introduced Pinch glove and Polhemus sensor as an input device. The extracted feature through preprocessing now acts as an input signal of the recognizer. For recognition 3D loci of Polhemus sensor, discrete HMM is also adopted. The alternative approach of two foregoing recognition systems uses the vision and and glove sensors together. The extracted mesh feature and 8 direction code from the locus tracking are introduced for further enhancing recognition performance. MLP trained by backpropagation is introduced here and its performance is compared to that of discrete HMM. (author). 32 refs., 44 figs., 21 tabs.

  4. Improving Mobility Performance in Low Vision With a Distance-Based Representation of the Visual Scene.

    Science.gov (United States)

    van Rheede, Joram J; Wilson, Iain R; Qian, Rose I; Downes, Susan M; Kennard, Christopher; Hicks, Stephen L

    2015-07-01

    Severe visual impairment can have a profound impact on personal independence through its effect on mobility. We investigated whether the mobility of people with vision low enough to be registered as blind could be improved by presenting the visual environment in a distance-based manner for easier detection of obstacles. We accomplished this by developing a pair of "residual vision glasses" (RVGs) that use a head-mounted depth camera and displays to present information about the distance of obstacles to the wearer as brightness, such that obstacles closer to the wearer are represented more brightly. We assessed the impact of the RVGs on the mobility performance of visually impaired participants during the completion of a set of obstacle courses. Participant position was monitored continuously, which enabled us to capture the temporal dynamics of mobility performance. This allowed us to find correlates of obstacle detection and hesitations in walking behavior, in addition to the more commonly used measures of trial completion time and number of collisions. All participants were able to use the smart glasses to navigate the course, and mobility performance improved for those visually impaired participants with the worst prior mobility performance. However, walking speed was slower and hesitations increased with the altered visual representation. A depth-based representation of the visual environment may offer low vision patients improvements in independent mobility. It is important for further work to explore whether practice can overcome the reductions in speed and increased hesitation that were observed in our trial.

  5. SAD-based stereo vision machine on a System-on-Programmable-Chip (SoPC).

    Science.gov (United States)

    Zhang, Xiang; Chen, Zhangwei

    2013-03-04

    This paper, proposes a novel solution for a stereo vision machine based on the System-on-Programmable-Chip (SoPC) architecture. The SOPC technology provides great convenience for accessing many hardware devices such as DDRII, SSRAM, Flash, etc., by IP reuse. The system hardware is implemented in a single FPGA chip involving a 32-bit Nios II microprocessor, which is a configurable soft IP core in charge of managing the image buffer and users' configuration data. The Sum of Absolute Differences (SAD) algorithm is used for dense disparity map computation. The circuits of the algorithmic module are modeled by the Matlab-based DSP Builder. With a set of configuration interfaces, the machine can process many different sizes of stereo pair images. The maximum image size is up to 512 K pixels. This machine is designed to focus on real time stereo vision applications. The stereo vision machine offers good performance and high efficiency in real time. Considering a hardware FPGA clock of 90 MHz, 23 frames of 640 × 480 disparity maps can be obtained in one second with 5 × 5 matching window and maximum 64 disparity pixels.

  6. SAD-Based Stereo Vision Machine on a System-on-Programmable-Chip (SoPC

    Directory of Open Access Journals (Sweden)

    Zhangwei Chen

    2013-03-01

    Full Text Available This paper, proposes a novel solution for a stereo vision machine based on the System-on-Programmable-Chip (SoPC architecture. The SOPC technology provides great convenience for accessing many hardware devices such as DDRII, SSRAM, Flash, etc., by IP reuse. The system hardware is implemented in a single FPGA chip involving a 32-bit Nios II microprocessor, which is a configurable soft IP core in charge of managing the image buffer and users’ configuration data. The Sum of Absolute Differences (SAD algorithm is used for dense disparity map computation. The circuits of the algorithmic module are modeled by the Matlab-based DSP Builder. With a set of configuration interfaces, the machine can process many different sizes of stereo pair images. The maximum image size is up to 512 K pixels. This machine is designed to focus on real time stereo vision applications. The stereo vision machine offers good performance and high efficiency in real time. Considering a hardware FPGA clock of 90 MHz, 23 frames of 640 × 480 disparity maps can be obtained in one second with 5 × 5 matching window and maximum 64 disparity pixels.

  7. Adaptive estimation and control with application to vision-based autonomous formation flight

    Science.gov (United States)

    Sattigeri, Ramachandra

    2007-05-01

    Modern Unmanned Aerial Vehicles (UAVs) are equipped with vision sensors because of their light-weight, low-cost characteristics and also their ability to provide a rich variety of information of the environment in which the UAVs are navigating in. The problem of vision based autonomous flight is very difficult and challenging since it requires bringing together concepts from image processing and computer vision, target tracking and state estimation, and flight guidance and control. This thesis focuses on the adaptive state estimation, guidance and control problems involved in vision-based formation flight. Specifically, the thesis presents a composite adaptation approach to the partial state estimation of a class of nonlinear systems with unmodeled dynamics. In this approach, a linear time-varying Kalman filter is the nominal state estimator which is augmented by the output of an adaptive neural network (NN) that is trained with two error signals. The benefit of the proposed approach is in its faster and more accurate adaptation to the modeling errors over a conventional approach. The thesis also presents two approaches to the design of adaptive guidance and control (G&C) laws for line-of-sight formation flight. In the first approach, the guidance and autopilot systems are designed separately and then combined together by assuming time-scale separation. The second approach is based on integrating the guidance and autopilot design process. The developed G&C laws using both approaches are adaptive to unmodeled leader aircraft acceleration and to own aircraft aerodynamic uncertainties. The thesis also presents theoretical justification based on Lyapunov-like stability analysis for integrating the adaptive state estimation and adaptive G&C designs. All the developed designs are validated in nonlinear, 6DOF fixed-wing aircraft simulations. Finally, the thesis presents a decentralized coordination strategy for vision-based multiple-aircraft formation control. In this

  8. Towards Domain Ontology Creation Based on a Taxonomy Structure in Computer Vision

    Directory of Open Access Journals (Sweden)

    Sadgal mohamed

    2016-02-01

    Full Text Available In computer vision to create a knowledge base usable by information systems, we need a data structure facilitating the information access. Artificial intelligence community uses the ontologies to structure and represent the domain knowledge. This information structure can be used as a database of many geographic information systems (GIS or information systems treating real objects for example road scenes, besides it can be utilized by other systems. For this, we provide a process to create a taxonomy structure based on new hierarchical image clustering method. The hierarchical relation is based on visual object features and contributes to build domain ontology.

  9. Separating monocular and binocular neural mechanisms mediating chromatic contextual interactions.

    Science.gov (United States)

    D'Antona, Anthony D; Christiansen, Jens H; Shevell, Steven K

    2014-04-17

    When seen in isolation, a light that varies in chromaticity over time is perceived to oscillate in color. Perception of that same time-varying light may be altered by a surrounding light that is also temporally varying in chromaticity. The neural mechanisms that mediate these contextual interactions are the focus of this article. Observers viewed a central test stimulus that varied in chromaticity over time within a larger surround that also varied in chromaticity at the same temporal frequency. Center and surround were presented either to the same eye (monocular condition) or to opposite eyes (dichoptic condition) at the same frequency (3.125, 6.25, or 9.375 Hz). Relative phase between center and surround modulation was varied. In both the monocular and dichoptic conditions, the perceived modulation depth of the central light depended on the relative phase of the surround. A simple model implementing a linear combination of center and surround modulation fit the measurements well. At the lowest temporal frequency (3.125 Hz), the surround's influence was virtually identical for monocular and dichoptic conditions, suggesting that at this frequency, the surround's influence is mediated primarily by a binocular neural mechanism. At higher frequencies, the surround's influence was greater for the monocular condition than for the dichoptic condition, and this difference increased with temporal frequency. Our findings show that two separate neural mechanisms mediate chromatic contextual interactions: one binocular and dominant at lower temporal frequencies and the other monocular and dominant at higher frequencies (6-10 Hz).

  10. The effect of contrast on monocular versus binocular reading performance.

    Science.gov (United States)

    Johansson, Jan; Pansell, Tony; Ygge, Jan; Seimyr, Gustaf Öqvist

    2014-05-14

    The binocular advantage in reading performance is typically small. On the other hand research shows binocular reading to be remarkably robust to degraded stimulus properties. We hypothesized that this robustness may stem from an increasing binocular contribution. The main objective was to compare monocular and binocular performance at different stimulus contrasts and assess the level of binocular superiority. A secondary objective was to assess any asymmetry in performance related to ocular dominance. In a balanced repeated measures experiment 18 subjects read texts at three levels of contrast monocularly and binocularly while their eye movements were recorded. The binocular advantage increased with reduced contrast producing a 7% slower monocular reading at 40% contrast, 9% slower at 20% contrast, and 21% slower at 10% contrast. A statistically significant interaction effect was found in fixation duration displaying a more adverse effect in the monocular condition at lowest contrast. No significant effects of ocular dominance were observed. The outcome suggests that binocularity contributes increasingly to reading performance as stimulus contrast decreases. The strongest difference between monocular and binocular performance was due to fixation duration. The findings may pose a clinical point that it may be necessary to consider tests at different contrast levels when estimating reading performance. © 2014 ARVO.

  11. A spiking neural network model of 3D perception for event-based neuromorphic stereo vision systems

    Science.gov (United States)

    Osswald, Marc; Ieng, Sio-Hoi; Benosman, Ryad; Indiveri, Giacomo

    2017-01-01

    Stereo vision is an important feature that enables machine vision systems to perceive their environment in 3D. While machine vision has spawned a variety of software algorithms to solve the stereo-correspondence problem, their implementation and integration in small, fast, and efficient hardware vision systems remains a difficult challenge. Recent advances made in neuromorphic engineering offer a possible solution to this problem, with the use of a new class of event-based vision sensors and neural processing devices inspired by the organizing principles of the brain. Here we propose a radically novel model that solves the stereo-correspondence problem with a spiking neural network that can be directly implemented with massively parallel, compact, low-latency and low-power neuromorphic engineering devices. We validate the model with experimental results, highlighting features that are in agreement with both computational neuroscience stereo vision theories and experimental findings. We demonstrate its features with a prototype neuromorphic hardware system and provide testable predictions on the role of spike-based representations and temporal dynamics in biological stereo vision processing systems. PMID:28079187

  12. A spiking neural network model of 3D perception for event-based neuromorphic stereo vision systems

    Science.gov (United States)

    Osswald, Marc; Ieng, Sio-Hoi; Benosman, Ryad; Indiveri, Giacomo

    2017-01-01

    Stereo vision is an important feature that enables machine vision systems to perceive their environment in 3D. While machine vision has spawned a variety of software algorithms to solve the stereo-correspondence problem, their implementation and integration in small, fast, and efficient hardware vision systems remains a difficult challenge. Recent advances made in neuromorphic engineering offer a possible solution to this problem, with the use of a new class of event-based vision sensors and neural processing devices inspired by the organizing principles of the brain. Here we propose a radically novel model that solves the stereo-correspondence problem with a spiking neural network that can be directly implemented with massively parallel, compact, low-latency and low-power neuromorphic engineering devices. We validate the model with experimental results, highlighting features that are in agreement with both computational neuroscience stereo vision theories and experimental findings. We demonstrate its features with a prototype neuromorphic hardware system and provide testable predictions on the role of spike-based representations and temporal dynamics in biological stereo vision processing systems.

  13. Hazard detection with a monocular bioptic telescope.

    Science.gov (United States)

    Doherty, Amy L; Peli, Eli; Luo, Gang

    2015-09-01

    The safety of bioptic telescopes for driving remains controversial. The ring scotoma, an area to the telescope eye due to the telescope magnification, has been the main cause of concern. This study evaluates whether bioptic users can use the fellow eye to detect in hazards driving videos that fall in the ring scotoma area. Twelve visually impaired bioptic users watched a series of driving hazard perception training videos and responded as soon as they detected a hazard while reading aloud letters presented on the screen. The letters were placed such that when reading them through the telescope the hazard fell in the ring scotoma area. Four conditions were tested: no bioptic and no reading, reading without bioptic, reading with a bioptic that did not occlude the fellow eye (non-occluding bioptic), and reading with a bioptic that partially-occluded the fellow eye. Eight normally sighted subjects performed the same task with the partially occluding bioptic detecting lateral hazards (blocked by the device scotoma) and vertical hazards (outside the scotoma) to further determine the cause-and-effect relationship between hazard detection and the fellow eye. There were significant differences in performance between conditions: 83% of hazards were detected with no reading task, dropping to 67% in the reading task with no bioptic, to 50% while reading with the non-occluding bioptic, and 34% while reading with the partially occluding bioptic. For normally sighted, detection of vertical hazards (53%) was significantly higher than lateral hazards (38%) with the partially occluding bioptic. Detection of driving hazards is impaired by the addition of a secondary reading like task. Detection is further impaired when reading through a monocular telescope. The effect of the partially-occluding bioptic supports the role of the non-occluded fellow eye in compensating for the ring scotoma. © 2015 The Authors Ophthalmic & Physiological Optics © 2015 The College of Optometrists.

  14. Measuring perceived depth in natural images and study of its relation with monocular and binocular depth cues

    Science.gov (United States)

    Lebreton, Pierre; Raake, Alexander; Barkowsky, Marcus; Le Callet, Patrick

    2014-03-01

    The perception of depth in images and video sequences is based on different depth cues. Studies have considered depth perception threshold as a function of viewing distance (Cutting and Vishton, 1995), the combination of different monocular depth cues and their quantitative relation with binocular depth cues and their different possible type of interactions (Landy, l995). But these studies only consider artificial stimuli and none of them attempts to provide a quantitative contribution of monocular and binocular depth cues compared to each other in the specific context of natural images. This study targets this particular application case. The evaluation of the strength of different depth cues compared to each other using a carefully designed image database to cover as much as possible different combinations of monocular (linear perspective, texture gradient, relative size and defocus blur) and binocular depth cues. The 200 images were evaluated in two distinct subjective experiments to evaluate separately perceived depth and different monocular depth cues. The methodology and the description of the definition of the different scales will be detailed. The image database (DC3Dimg) is also released for the scientific community.

  15. On-line welding quality inspection system for steel pipe based on machine vision

    Science.gov (United States)

    Yang, Yang

    2017-05-01

    In recent years, high frequency welding has been widely used in production because of its advantages of simplicity, reliability and high quality. In the production process, how to effectively control the weld penetration welding, ensure full penetration, weld uniform, so as to ensure the welding quality is to solve the problem of the present stage, it is an important research field in the field of welding technology. In this paper, based on the study of some methods of welding inspection, a set of on-line welding quality inspection system based on machine vision is designed.

  16. Affordance estimation for vision-based object replacement on a humanoid robot

    DEFF Research Database (Denmark)

    Mustafa, Wail; Wächter, Mirko; Szedmak, Sandor

    2016-01-01

    In this paper, we address the problem of finding replacements of missing objects, involved in the execution of manipulation tasks. Our approach is based on estimating functional affordances for the unknown objects in order to propose replacements. We use a vision-based affordance estimation system...... large-scale datasets. The results indicate that the system is able to successfully predict the affordances of novel objects. We also implement our system on a humanoid robot and demonstrate the affordance estimation in a real scene....

  17. Enhanced depth perception using hyperstereo vision

    Science.gov (United States)

    Watkins, Wendell R.

    1997-06-01

    Recent stereo vision experiments demonstrated the enhancement of depth perception over single line of sight vision for improved vehicular navigation and target acquisition processes. The experiments involves the use of stereo vision headsets connected to visible and 8 - 12 micrometers IR imagers. The imagers were separated by up to 50 m (i.e., wider platform separation than human vision, or hyperstereo) and equipped with telescopes for viewing at ranges of tens of meters up to 4 km. The important findings were: (1) human viewers were able to discern terrain undulations for obstacle avoidance for vehicular navigation, and (2) human viewers were able to detect depth features within the scenes that enhanced the target acquisition process over using monocular or single line of sight viewing. For vehicular navigation improvement, stereo goggles were developed for headset display and simultaneous see through instrumentation viewing for vehicular navigation enhancement. For detection, the depth cues can be used to detect even salient target features.

  18. Global localization from monocular SLAM on a mobile phone.

    Science.gov (United States)

    Ventura, Jonathan; Arth, Clemens; Reitmayr, Gerhard; Schmalstieg, Dieter

    2014-04-01

    We propose the combination of a keyframe-based monocular SLAM system and a global localization method. The SLAM system runs locally on a camera-equipped mobile client and provides continuous, relative 6DoF pose estimation as well as keyframe images with computed camera locations. As the local map expands, a server process localizes the keyframes with a pre-made, globally-registered map and returns the global registration correction to the mobile client. The localization result is updated each time a keyframe is added, and observations of global anchor points are added to the client-side bundle adjustment process to further refine the SLAM map registration and limit drift. The end result is a 6DoF tracking and mapping system which provides globally registered tracking in real-time on a mobile device, overcomes the difficulties of localization with a narrow field-of-view mobile phone camera, and is not limited to tracking only in areas covered by the offline reconstruction.

  19. 3D environment capture from monocular video and inertial data

    Science.gov (United States)

    Clark, R. Robert; Lin, Michael H.; Taylor, Colin J.

    2006-02-01

    This paper presents experimental methods and results for 3D environment reconstruction from monocular video augmented with inertial data. One application targets sparsely furnished room interiors, using high quality handheld video with a normal field of view, and linear accelerations and angular velocities from an attached inertial measurement unit. A second application targets natural terrain with manmade structures, using heavily compressed aerial video with a narrow field of view, and position and orientation data from the aircraft navigation system. In both applications, the translational and rotational offsets between the camera and inertial reference frames are initially unknown, and only a small fraction of the scene is visible in any one video frame. We start by estimating sparse structure and motion from 2D feature tracks using a Kalman filter and/or repeated, partial bundle adjustments requiring bounded time per video frame. The first application additionally incorporates a weak assumption of bounding perpendicular planes to minimize a tendency of the motion estimation to drift, while the second application requires tight integration of the navigational data to alleviate the poor conditioning caused by the narrow field of view. This is followed by dense structure recovery via graph-cut-based multi-view stereo, meshing, and optional mesh simplification. Finally, input images are texture-mapped onto the 3D surface for rendering. We show sample results from multiple, novel viewpoints.

  20. Eyegaze Detection from Monocular Camera Image for Eyegaze Communication System

    Science.gov (United States)

    Ohtera, Ryo; Horiuchi, Takahiko; Kotera, Hiroaki

    An eyegaze interface is one of the key technologies as an input device in the ubiquitous-computing society. In particular, an eyegaze communication system is very important and useful for severely handicapped users such as quadriplegic patients. Most of the conventional eyegaze tracking algorithms require specific light sources, equipment and devices. In this study, a simple eyegaze detection algorithm is proposed using a single monocular video camera. The proposed algorithm works under the condition of fixed head pose, but slight movement of the face is accepted. In our system, we assume that all users have the same eyeball size based on physiological eyeball models. However, we succeed to calibrate the physiologic movement of the eyeball center depending on the gazing direction by approximating it as a change in the eyeball radius. In the gaze detection stage, the iris is extracted from a captured face frame by using the Hough transform. Then, the eyegaze angle is derived by calculating the Euclidean distance of the iris centers between the extracted frame and a reference frame captured in the calibration process. We apply our system to an eyegaze communication interface, and verified the performance through key typing experiments with a visual keyboard on display.

  1. Ernst Mach and the episode of the monocular depth sensations.

    Science.gov (United States)

    Banks, E C

    2001-01-01

    Although Ernst Mach is widely recognized in psychology for his discovery of the effects of lateral inhibition in the retina ("Mach Bands"), his contributions to the theory of depth perception are not as well known. Mach proposed that steady luminance gradients triggered sensations of depth. He also expanded on Ewald Hering's hypothesis of "monocular depth sensations," arguing that they were subject to the same principle of lateral inhibition as light sensations were. Even after Hermann von Helmholtz's attack on Hering in 1866, Mach continued to develop theories involving the monocular depth sensations, proposing an explanation of perspective drawings in which the mutually inhibiting depth sensations scaled to a mean depth. Mach also contemplated a theory of stereopsis in which monocular depth perception played the primary role. Copyright 2001 John Wiley & Sons, Inc.

  2. A Comparison of Monocular and Binocular Depth Perception in 5- and 7-Month-Old Infants.

    Science.gov (United States)

    Granrud, Carl E.; And Others

    1984-01-01

    Compares monocular depth perception with binocular depth perception in five- to seven-month-old infants. Reaching preferences (dependent measure) observed in the monocular condition indicated sensitivity to monocular depth information. Binocular viewing resulted in a far more consistent tendency to reach for the nearer object. (Author)

  3. Stereo-vision-based cooperative-vehicle positioning using OCC and neural networks

    Science.gov (United States)

    Ifthekhar, Md. Shareef; Saha, Nirzhar; Jang, Yeong Min

    2015-10-01

    Vehicle positioning has been subjected to extensive research regarding driving safety measures and assistance as well as autonomous navigation. The most common positioning technique used in automotive positioning is the global positioning system (GPS). However, GPS is not reliably accurate because of signal blockage caused by high-rise buildings. In addition, GPS is error prone when a vehicle is inside a tunnel. Moreover, GPS and other radio-frequency-based approaches cannot provide orientation information or the position of neighboring vehicles. In this study, we propose a cooperative-vehicle positioning (CVP) technique by using the newly developed optical camera communications (OCC). The OCC technique utilizes image sensors and cameras to receive and decode light-modulated information from light-emitting diodes (LEDs). A vehicle equipped with an OCC transceiver can receive positioning and other information such as speed, lane change, driver's condition, etc., through optical wireless links of neighboring vehicles. Thus, the target vehicle position that is too far away to establish an OCC link can be determined by a computer-vision-based technique combined with the cooperation of neighboring vehicles. In addition, we have devised a back-propagation (BP) neural-network learning method for positioning and range estimation for CVP. The proposed neural-network-based technique can estimate target vehicle position from only two image points of target vehicles using stereo vision. For this, we use rear LEDs on target vehicles as image points. We show from simulation results that our neural-network-based method achieves better accuracy than that of the computer-vision method.

  4. Visual control of wheeled mobile robots unifying vision and control in generic approaches

    CERN Document Server

    Becerra, Héctor M

    2014-01-01

    Vision-based control of wheeled mobile robots is an interesting field of research from a scientific and even social point of view due to its potential applicability. This book presents a formal treatment of some aspects of control theory applied to the problem of vision-based pose regulation of wheeled mobile robots. In this problem, the robot has to reach a desired position and orientation, which are specified by a target image. It is faced in such a way that vision and control are unified to achieve stability of the closed loop, a large region of convergence, without local minima, and good robustness against parametric uncertainty. Three different control schemes that rely on monocular vision as unique sensor are presented and evaluated experimentally. A common benefit of these approaches is that they are valid for imaging systems obeying approximately a central projection model, e.g., conventional cameras, catadioptric systems and some fisheye cameras. Thus, the presented control schemes are generic approa...

  5. Extreme Learning Machine and Moving Least Square Regression Based Solar Panel Vision Inspection

    Directory of Open Access Journals (Sweden)

    Heng Liu

    2017-01-01

    Full Text Available In recent years, learning based machine intelligence has aroused a lot of attention across science and engineering. Particularly in the field of automatic industry inspection, the machine learning based vision inspection plays a more and more important role in defect identification and feature extraction. Through learning from image samples, many features of industry objects, such as shapes, positions, and orientations angles, can be obtained and then can be well utilized to determine whether there is defect or not. However, the robustness and the quickness are not easily achieved in such inspection way. In this work, for solar panel vision inspection, we present an extreme learning machine (ELM and moving least square regression based approach to identify solder joint defect and detect the panel position. Firstly, histogram peaks distribution (HPD and fractional calculus are applied for image preprocessing. Then an ELM-based defective solder joints identification is discussed in detail. Finally, moving least square regression (MLSR algorithm is introduced for solar panel position determination. Experimental results and comparisons show that the proposed ELM and MLSR based inspection method is efficient not only in detection accuracy but also in processing speed.

  6. A Review of Machine-Vision-Based Analysis of Wireless Capsule Endoscopy Video

    Directory of Open Access Journals (Sweden)

    Yingju Chen

    2012-01-01

    Full Text Available Wireless capsule endoscopy (WCE enables a physician to diagnose a patient's digestive system without surgical procedures. However, it takes 1-2 hours for a gastroenterologist to examine the video. To speed up the review process, a number of analysis techniques based on machine vision have been proposed by computer science researchers. In order to train a machine to understand the semantics of an image, the image contents need to be translated into numerical form first. The numerical form of the image is known as image abstraction. The process of selecting relevant image features is often determined by the modality of medical images and the nature of the diagnoses. For example, there are radiographic projection-based images (e.g., X-rays and PET scans, tomography-based images (e.g., MRT and CT scans, and photography-based images (e.g., endoscopy, dermatology, and microscopic histology. Each modality imposes unique image-dependent restrictions for automatic and medically meaningful image abstraction processes. In this paper, we review the current development of machine-vision-based analysis of WCE video, focusing on the research that identifies specific gastrointestinal (GI pathology and methods of shot boundary detection.

  7. Vision-based markerless registration using stereo vision and an augmented reality surgical navigation system: a pilot study.

    Science.gov (United States)

    Suenaga, Hideyuki; Tran, Huy Hoang; Liao, Hongen; Masamune, Ken; Dohi, Takeyoshi; Hoshi, Kazuto; Takato, Tsuyoshi

    2015-11-02

    This study evaluated the use of an augmented reality navigation system that provides a markerless registration system using stereo vision in oral and maxillofacial surgery. A feasibility study was performed on a subject, wherein a stereo camera was used for tracking and markerless registration. The computed tomography data obtained from the volunteer was used to create an integral videography image and a 3-dimensional rapid prototype model of the jaw. The overlay of the subject's anatomic site and its 3D-IV image were displayed in real space using a 3D-AR display. Extraction of characteristic points and teeth matching were done using parallax images from two stereo cameras for patient-image registration. Accurate registration of the volunteer's anatomy with IV stereoscopic images via image matching was done using the fully automated markerless system, which recognized the incisal edges of the teeth and captured information pertaining to their position with an average target registration error of < 1 mm. These 3D-CT images were then displayed in real space with high accuracy using AR. Even when the viewing position was changed, the 3D images could be observed as if they were floating in real space without using special glasses. Teeth were successfully used for registration via 3D image (contour) matching. This system, without using references or fiducial markers, displayed 3D-CT images in real space with high accuracy. The system provided real-time markerless registration and 3D image matching via stereo vision, which, combined with AR, could have significant clinical applications.

  8. Computer vision-based apple grading for golden delicious apples based on surface features

    Directory of Open Access Journals (Sweden)

    Payman Moallem

    2017-03-01

    Full Text Available In this paper, a computer vision-based algorithm for golden delicious apple grading is proposed which works in six steps. Non-apple pixels as background are firstly removed from input images. Then, stem end is detected by combination of morphological methods and Mahalanobis distant classifier. Calyx region is also detected by applying K-means clustering on the Cb component in YCbCr color space. After that, defects segmentation is achieved using Multi-Layer Perceptron (MLP neural network. In the next step, stem end and calyx regions are removed from defected regions to refine and improve apple grading process. Then, statistical, textural and geometric features from refined defected regions are extracted. Finally, for apple grading, a comparison between performance of Support Vector Machine (SVM, MLP and K-Nearest Neighbor (KNN classifiers is done. Classification is done in two manners which in the first one, an input apple is classified into two categories of healthy and defected. In the second manner, the input apple is classified into three categories of first rank, second rank and rejected ones. In both grading steps, SVM classifier works as the best one with recognition rate of 92.5% and 89.2% for two categories (healthy and defected and three quality categories (first rank, second rank and rejected ones, among 120 different golden delicious apple images, respectively, considering K-folding with K = 5. Moreover, the accuracy of the proposed segmentation algorithms including stem end detection and calyx detection are evaluated for two different apple image databases.

  9. Vision Examination Protocol for Archery Athletes Along With an Introduction to Sports Vision

    Directory of Open Access Journals (Sweden)

    Mohammadi

    2016-03-01

    Full Text Available Introduction Visual skills are one of the main pillars of intangible faculties of athletes that can influence their performance. Great number of vision tests used to assess the visual skills and it will be irrational to perform all vision tests for every sport. Objectives The purpose of this protocol article is to present a relatively comprehensive battery of tests and assessments on static and dynamic aspects of sight which seems relevant to sports vision and introduce the most useful ones for archery. Materials and Methods Through extensive review of the literature, visual skills and respective tests were listed; such as ‘visual acuity, ‘contrast sensitivity’, ‘stereo-acuity’, ‘ocular alignment’, and ‘eye dominance’. Athletes were defined as “elite” and “non-elite” category based on their past performance. Dominance was considered for eye and hand; binocular or monocular aiming was planned to be recorded. Illumination condition was defined as to simulate the real archery condition to the extent possible. The full cycle of examinations and their order for each athlete was sketched (and estimated to take 40 minutes. Protocol was piloted in an eye hospital. Female and male archers aged 18 - 38 years who practiced compound and recurve archery with a history of more than 6 months were included. Conclusions We managed to select and design a customized examination protocol for archery (a sight-intensive and aiming type of sports, serving skill assessment and research purposes. Our definition for elite and non-elite athletes can help to define sports talent and devise skill development methods as we compare the performance of these two groups. In our pilot, we identified 8 “archery figures” (by hand dominance, eye dominance and binocularity and highlighted the concept “congruence” (dominant hand and eye in the same side in archery performance.

  10. Vision Examination Protocol for Archery Athletes Along With an Introduction to Sports Vision.

    Science.gov (United States)

    Mohammadi, Seyed Farzad; Aghazade Amiri, Mohammad; Naderifar, Homa; Rakhshi, Elham; Vakilian, Banafsheh; Ashrafi, Elham; Behesht-Nejad, Amir-Houshang

    2016-03-01

    Visual skills are one of the main pillars of intangible faculties of athletes that can influence their performance. Great number of vision tests used to assess the visual skills and it will be irrational to perform all vision tests for every sport. The purpose of this protocol article is to present a relatively comprehensive battery of tests and assessments on static and dynamic aspects of sight which seems relevant to sports vision and introduce the most useful ones for archery. Through extensive review of the literature, visual skills and respective tests were listed; such as 'visual acuity, 'contrast sensitivity', 'stereo-acuity', 'ocular alignment', and 'eye dominance'. Athletes were defined as "elite" and "non-elite" category based on their past performance. Dominance was considered for eye and hand; binocular or monocular aiming was planned to be recorded. Illumination condition was defined as to simulate the real archery condition to the extent possible. The full cycle of examinations and their order for each athlete was sketched (and estimated to take 40 minutes). Protocol was piloted in an eye hospital. Female and male archers aged 18 - 38 years who practiced compound and recurve archery with a history of more than 6 months were included. We managed to select and design a customized examination protocol for archery (a sight-intensive and aiming type of sports), serving skill assessment and research purposes. Our definition for elite and non-elite athletes can help to define sports talent and devise skill development methods as we compare the performance of these two groups. In our pilot, we identified 8 "archery figures" (by hand dominance, eye dominance and binocularity) and highlighted the concept "congruence" (dominant hand and eye in the same side) in archery performance.

  11. Fractal coding of wavelet image based on human vision contrast-masking effect

    Science.gov (United States)

    Wei, Hai; Shen, Lansun

    2000-06-01

    In this paper, a fractal-based compression approach of wavelet image is presented. The scheme tries to make full use of the sensitivity features of the human visual system. With the wavelet-based multi-resolution representation of image, detail vectors of each high frequency sub-image are constructed in accordance with its spatial orientation in order to grasp the edge information to which human observer is sensitive. Then a multi-level selection algorithm based on human vision's contrast masking effect is proposed to make the decision whether a detail vector is coded or not. Those vectors below the contrast threshold are discarded without introducing visual artifacts because of the ignorance of human vision. As for the redundancy of the retained vectors, different fractal- based methods are employed to decrease the correlation in single sub-image and between the different resolution sub- images with the same orientation. Experimental results suggest the efficiency of the proposed scheme. With the standard test image, our approach outperforms the EZW algorithm and the JPEG method.

  12. Vision-Based Perception and Classification of Mosquitoes Using Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Masataka Fuchida

    2017-01-01

    Full Text Available The need for a novel automated mosquito perception and classification method is becoming increasingly essential in recent years, with steeply increasing number of mosquito-borne diseases and associated casualties. There exist remote sensing and GIS-based methods for mapping potential mosquito inhabitants and locations that are prone to mosquito-borne diseases, but these methods generally do not account for species-wise identification of mosquitoes in closed-perimeter regions. Traditional methods for mosquito classification involve highly manual processes requiring tedious sample collection and supervised laboratory analysis. In this research work, we present the design and experimental validation of an automated vision-based mosquito classification module that can deploy in closed-perimeter mosquito inhabitants. The module is capable of identifying mosquitoes from other bugs such as bees and flies by extracting the morphological features, followed by support vector machine-based classification. In addition, this paper presents the results of three variants of support vector machine classifier in the context of mosquito classification problem. This vision-based approach to the mosquito classification problem presents an efficient alternative to the conventional methods for mosquito surveillance, mapping and sample image collection. Experimental results involving classification between mosquitoes and a predefined set of other bugs using multiple classification strategies demonstrate the efficacy and validity of the proposed approach with a maximum recall of 98%.

  13. ABHIVYAKTI: A Vision Based Intelligent System for Elder and Sick Persons

    CERN Document Server

    Chaudhary, Ankit

    2011-01-01

    This paper describes an intelligent system ABHIVYAKTI, which would be pervasive in nature and based on the Computer Vision. It would be very easy in use and deployment. Elder and sick people who are not able to talk or walk, they are dependent on other human beings and need continuous monitoring, while our system provides flexibility to the sick or elder person to announce his or her need to their caretaker by just showing a particular gesture with the developed system, if the caretaker is not nearby. This system will use fingertip detection techniques for acquiring gesture and Artificial Neural Networks (ANNs) will be used for gesture recognition.

  14. Road Interpretation for Driver Assistance Based on an Early Cognitive Vision System

    DEFF Research Database (Denmark)

    Baseski, Emre; Jensen, Lars Baunegaard With; Pugeault, Nicolas

    2009-01-01

    scale maps of the road. We make use of temporal and spatial disambiguation mechanisms to increase the reliability of visually extracted 2D and 3D information. This information is then used to interpret the layout of the road by using lane markers that are detected via Bayesian reasoning. We also......In this work, we address the problem of road interpretation for driver assistance based on an early cognitive vision system. The structure of a road and the relevant traffic are interpreted in terms of ego-motion estimation of the car, independently moving objects on the road, lane markers and large...

  15. Navigation control for mobile robot based on vision and ultrasonic sensors

    Science.gov (United States)

    Takahashi, Satoru; Nara, Shunsuke

    2007-10-01

    This paper treats the navigation problem of a mobile robot based on vision information and ultrasonic data. In our method, by calculating the optical flow on the images, the mobile robot can detect obstacles which exist ahead of it, further avoiding the area of obstacles, it can make the optimal trajectory to the final goal. Then, in order to generate the optimal trajectory, the distance between a mobile robot and obstacle is needed and then is obtained by evaluating a function with ultrasonic information. Through some experiments, we show how our proposed method is effective.

  16. Deforming analysis of sheet metal based on stereo vision and coordinate grid

    Institute of Scientific and Technical Information of China (English)

    Hongqin Wei; Dehong Yu; Xueyu Ruan; Youqing Wang

    2004-01-01

    A new approach based on stereo vision technology is introduced to analyze sheet metal deformation. By measuring the deformed circle grids that are printed on the sheet surface before forming, the strain distribution of the workpiece is obtained. The measurement and analysis results can be used to verify numerical simulation results and guide production. To get good accuracy,some new techniques are employed: camera calibration based on genetic algorithm, feature abstraction based on self-adaptive technology, image matching based on structure feature and camera modeling pre-constrains, and parameter calculation based on curve and surface optimization. The experimental values show that the approach proposed is rational and practical, which can provide better measurement accuracy with less time than the conventional method.

  17. Colorimetric evaluation of iPhone apps for colour vision tests based on the Ishihara test

    National Research Council Canada - National Science Library

    Dain, Stephen J; AlMerdef, Ali

    2016-01-01

    ...) providing colour vision testing would appear as an option. In this study, the colorimetric characteristics of five available iPhone apps for colour vision testing are assessed as a prequel to possible clinical evaluation...

  18. The Influence of Monocular Spatial Cues on Vergence Eye Movements in Monocular and Binocular Viewing of 3-D and 2-D Stimuli.

    Science.gov (United States)

    Batvinionak, Anton A; Gracheva, Maria A; Bolshakov, Andrey S; Rozhkova, Galina I

    2015-01-01

    The influence of monocular spatial cues on the vergence eye movements was studied in two series of experiments: (I) the subjects were viewing a 3-D video and also its 2-D version-binocularly and monocularly; and (II) in binocular and monocular viewing conditions, the subjects were presented with stationary 2-D stimuli containing or not containing some monocular indications of spatial arrangement. The results of the series (I) showed that, in binocular viewing conditions, the vergence eye movements were only present in the case of 3-D but not 2-D video, while in the course of monocular viewing of 2-D video, some regular vergence eye movements could be revealed, suggesting that the occluded eye position could be influenced by the spatial organization of the scene reconstructed on the basis of the monocular depth information provided by the viewing eye. The data obtained in series (II), in general, seem to support this hypothesis. © The Author(s) 2015.

  19. Vision Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The Vision Lab personnel perform research, development, testing and evaluation of eye protection and vision performance. The lab maintains and continues to develop...

  20. Vision Screening

    Science.gov (United States)

    ... of Prematurity Strabismus Stye (defined) Vision Screening Vision Screening Recommendations Loading... Most Common Searches Adult Strabismus Amblyopia Cataract Conjunctivitis Corneal Abrasions Dilating Eye ...

  1. Deep learning-based artificial vision for grasp classification in myoelectric hands

    Science.gov (United States)

    Ghazaei, Ghazal; Alameer, Ali; Degenaar, Patrick; Morgan, Graham; Nazarpour, Kianoush

    2017-06-01

    Objective. Computer vision-based assistive technology solutions can revolutionise the quality of care for people with sensorimotor disorders. The goal of this work was to enable trans-radial amputees to use a simple, yet efficient, computer vision system to grasp and move common household objects with a two-channel myoelectric prosthetic hand. Approach. We developed a deep learning-based artificial vision system to augment the grasp functionality of a commercial prosthesis. Our main conceptual novelty is that we classify objects with regards to the grasp pattern without explicitly identifying them or measuring their dimensions. A convolutional neural network (CNN) structure was trained with images of over 500 graspable objects. For each object, 72 images, at {{5}\\circ} intervals, were available. Objects were categorised into four grasp classes, namely: pinch, tripod, palmar wrist neutral and palmar wrist pronated. The CNN setting was first tuned and tested offline and then in realtime with objects or object views that were not included in the training set. Main results. The classification accuracy in the offline tests reached 85 % for the seen and 75 % for the novel objects; reflecting the generalisability of grasp classification. We then implemented the proposed framework in realtime on a standard laptop computer and achieved an overall score of 84 % in classifying a set of novel as well as seen but randomly-rotated objects. Finally, the system was tested with two trans-radial amputee volunteers controlling an i-limb UltraTM prosthetic hand and a motion controlTM prosthetic wrist; augmented with a webcam. After training, subjects successfully picked up and moved the target objects with an overall success of up to 88 % . In addition, we show that with training, subjects’ performance improved in terms of time required to accomplish a block of 24 trials despite a decreasing level of visual feedback. Significance. The proposed design constitutes a substantial

  2. Performance Analysis of Vision-Based Deep Web Data Extraction for Web Document Clustering

    Directory of Open Access Journals (Sweden)

    M. Lavanya

    2013-01-01

    Full Text Available Web Data Extraction is a critical task by applying various scientific tools and in a broad range of application domains. To extract data from multiple web sites are becoming more obscure, as well to design of web information extraction systems becomes more complex and time-consuming. We also present in this paper so far various risks in web data extraction. Identifying data region from web is a noteworthy crisis for information extraction from the web page. In this paper, performance of vision-based deep web data extraction for web document clustering is presented with experimental result. The proposed approach comprises of two phases: 1 Vision-based web data extraction, where output of phase I is given to second phase and 2 web document clustering. In phase 1, the web page information is segmented into various chunks. From which, surplus noise and duplicate chunks are removed using three parameters, such as hyperlink percentage, noise score and cosine similarity. To identify the relevant chunk, three parameters such as Title word Relevancy, Keyword frequency-based chunk selection, Position features are used and then, a set of keywords are extracted from those main chunks. Finally, the extracted keywords are subjected to web document clustering using Fuzzy c-means clustering (FCM. The experimentation has been performed on two different datasets and the results showed that the proposed VDEC method can achieve stable and good results of about 99.2% and 99.1% precision value in both datasets.

  3. Design of jitter compensation algorithm for robot vision based on optical flow and Kalman filter.

    Science.gov (United States)

    Wang, B R; Jin, Y L; Shao, D L; Xu, Y

    2014-01-01

    Image jitters occur in the video of the autonomous robot moving on bricks road, which will reduce robot operation precision based on vision. In order to compensate the image jitters, the affine transformation kinematics were established for obtaining the six image motion parameters. The feature point pair detecting method was designed based on Eigen-value of the feature windows gradient matrix, and the motion parameters equation was solved using the least square method and the matching point pairs got based on the optical flow. The condition number of coefficient matrix was proposed to quantificationally analyse the effect of matching errors on parameters solving errors. Kalman filter was adopted to smooth image motion parameters. Computing cases show that more point pairs are beneficial for getting more precise motion parameters. The integrated jitters compensation software was developed with feature points detecting in subwindow. And practical experiments were conducted on two mobile robots. Results show that the compensation costing time is less than frame sample time and Kalman filter is valid for robot vision jitters compensation.

  4. Vision-based system identification technique for building structures using a motion capture system

    Science.gov (United States)

    Oh, Byung Kwan; Hwang, Jin Woo; Kim, Yousok; Cho, Tongjun; Park, Hyo Seon

    2015-11-01

    This paper presents a new vision-based system identification (SI) technique for building structures by using a motion capture system (MCS). The MCS with outstanding capabilities for dynamic response measurements can provide gage-free measurements of vibrations through the convenient installation of multiple markers. In this technique, from the dynamic displacement responses measured by MCS, the dynamic characteristics (natural frequency, mode shape, and damping ratio) of building structures are extracted after the processes of converting the displacement from MCS to acceleration and conducting SI by frequency domain decomposition. A free vibration experiment on a three-story shear frame was conducted to validate the proposed technique. The SI results from the conventional accelerometer-based method were compared with those from the proposed technique and showed good agreement, which confirms the validity and applicability of the proposed vision-based SI technique for building structures. Furthermore, SI directly employing MCS measured displacements to FDD was performed and showed identical results to those of conventional SI method.

  5. Image Processing Strategies Based on a Visual Saliency Model for Object Recognition Under Simulated Prosthetic Vision.

    Science.gov (United States)

    Wang, Jing; Li, Heng; Fu, Weizhen; Chen, Yao; Li, Liming; Lyu, Qing; Han, Tingting; Chai, Xinyu

    2016-01-01

    Retinal prostheses have the potential to restore partial vision. Object recognition in scenes of daily life is one of the essential tasks for implant wearers. Still limited by the low-resolution visual percepts provided by retinal prostheses, it is important to investigate and apply image processing methods to convey more useful visual information to the wearers. We proposed two image processing strategies based on Itti's visual saliency map, region of interest (ROI) extraction, and image segmentation. Itti's saliency model generated a saliency map from the original image, in which salient regions were grouped into ROI by the fuzzy c-means clustering. Then Grabcut generated a proto-object from the ROI labeled image which was recombined with background and enhanced in two ways--8-4 separated pixelization (8-4 SP) and background edge extraction (BEE). Results showed that both 8-4 SP and BEE had significantly higher recognition accuracy in comparison with direct pixelization (DP). Each saliency-based image processing strategy was subject to the performance of image segmentation. Under good and perfect segmentation conditions, BEE and 8-4 SP obtained noticeably higher recognition accuracy than DP, and under bad segmentation condition, only BEE boosted the performance. The application of saliency-based image processing strategies was verified to be beneficial to object recognition in daily scenes under simulated prosthetic vision. They are hoped to help the development of the image processing module for future retinal prostheses, and thus provide more benefit for the patients.

  6. Design of Jitter Compensation Algorithm for Robot Vision Based on Optical Flow and Kalman Filter

    Directory of Open Access Journals (Sweden)

    B. R. Wang

    2014-01-01

    Full Text Available Image jitters occur in the video of the autonomous robot moving on bricks road, which will reduce robot operation precision based on vision. In order to compensate the image jitters, the affine transformation kinematics were established for obtaining the six image motion parameters. The feature point pair detecting method was designed based on Eigen-value of the feature windows gradient matrix, and the motion parameters equation was solved using the least square method and the matching point pairs got based on the optical flow. The condition number of coefficient matrix was proposed to quantificationally analyse the effect of matching errors on parameters solving errors. Kalman filter was adopted to smooth image motion parameters. Computing cases show that more point pairs are beneficial for getting more precise motion parameters. The integrated jitters compensation software was developed with feature points detecting in subwindow. And practical experiments were conducted on two mobile robots. Results show that the compensation costing time is less than frame sample time and Kalman filter is valid for robot vision jitters compensation.

  7. Computer vision-based method for classification of wheat grains using artificial neural network.

    Science.gov (United States)

    Sabanci, Kadir; Kayabasi, Ahmet; Toktas, Abdurrahim

    2017-06-01

    A simplified computer vision-based application using artificial neural network (ANN) depending on multilayer perceptron (MLP) for accurately classifying wheat grains into bread or durum is presented. The images of 100 bread and 100 durum wheat grains are taken via a high-resolution camera and subjected to pre-processing. The main visual features of four dimensions, three colors and five textures are acquired using image-processing techniques (IPTs). A total of 21 visual features are reproduced from the 12 main features to diversify the input population for training and testing the ANN model. The data sets of visual features are considered as input parameters of the ANN model. The ANN with four different input data subsets is modelled to classify the wheat grains into bread or durum. The ANN model is trained with 180 grains and its accuracy tested with 20 grains from a total of 200 wheat grains. Seven input parameters that are most effective on the classifying results are determined using the correlation-based CfsSubsetEval algorithm to simplify the ANN model. The results of the ANN model are compared in terms of accuracy rate. The best result is achieved with a mean absolute error (MAE) of 9.8 × 10(-6) by the simplified ANN model. This shows that the proposed classifier based on computer vision can be successfully exploited to automatically classify a variety of grains. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  8. Stereo vision-based pedestrian detection using multiple features for automotive application

    Science.gov (United States)

    Lee, Chung-Hee; Kim, Dongyoung

    2015-12-01

    In this paper, we propose a stereo vision-based pedestrian detection using multiple features for automotive application. The disparity map from stereo vision system and multiple features are utilized to enhance the pedestrian detection performance. Because the disparity map offers us 3D information, which enable to detect obstacles easily and reduce the overall detection time by removing unnecessary backgrounds. The road feature is extracted from the v-disparity map calculated by the disparity map. The road feature is a decision criterion to determine the presence or absence of obstacles on the road. The obstacle detection is performed by comparing the road feature with all columns in the disparity. The result of obstacle detection is segmented by the bird's-eye-view mapping to separate the obstacle area which has multiple objects into single obstacle area. The histogram-based clustering is performed in the bird's-eye-view map. Each segmented result is verified by the classifier with the training model. To enhance the pedestrian recognition performance, multiple features such as HOG, CSS, symmetry features are utilized. In particular, the symmetry feature is proper to represent the pedestrian standing or walking. The block-based symmetry feature is utilized to minimize the type of image and the best feature among the three symmetry features of H-S-V image is selected as the symmetry feature in each pixel. ETH database is utilized to verify our pedestrian detection algorithm.

  9. Estimating 3D positions and velocities of projectiles from monocular views.

    Science.gov (United States)

    Ribnick, Evan; Atev, Stefan; Papanikolopoulos, Nikolaos P

    2009-05-01

    In this paper, we consider the problem of localizing a projectile in 3D based on its apparent motion in a stationary monocular view. A thorough theoretical analysis is developed, from which we establish the minimum conditions for the existence of a unique solution. The theoretical results obtained have important implications for applications involving projectile motion. A robust, nonlinear optimization-based formulation is proposed, and the use of a local optimization method is justified by detailed examination of the local convexity structure of the cost function. The potential of this approach is validated by experimental results.

  10. Industrial vision

    DEFF Research Database (Denmark)

    Knudsen, Ole

    1998-01-01

    of an implementation in real production environments. The theory for projection of world points into images is concentrated upon the direct linear transformation (DLT), also called the Extended Pinhole model, and the stability of this method. A complete list of formulas for calculating all parameters in the model...... is present ed, and the variability of the parameters is examined and described. The concept of using CAD together with vision information is based on the fact that all items processed at OSS have an associated complete 3D CAD model that is accessible at all production states. This concept gives numerous...... possibilities for using vision in applications which otherwise would be very difficult to automate. The requirement for low tolerances in production is, despite the huge dimensions of the items involved, extreme. This fact makes great demands on the ability to do robust sub pixel estimation. A new method based...

  11. Danish Rural Eye Study: the association of preschool vision screening with the prevalence of amblyopia.

    Science.gov (United States)

    Høeg, Tracy B; Moldow, Birgitte; Ellervik, Christina; Klemp, Kristian; Erngaard, Ditte; la Cour, Morten; Buch, Helena

    2015-06-01

    To determine the prevalence of amblyopia in Denmark before and after the initiation of the Danish national preschool vision screening programme. In a population-based cross-sectional study, 3826 participants of the Danish General Suburban Population Study (GESUS) aged 20 years and older from a Danish rural municipality received a complete general health examination and an ophthalmological interview and examination. This study included a comprehensive ophthalmologic interview, measurement of best corrected visual acuity (BCVA) in each eye, Hirschberg's test for strabismus and two 45-degree retinal fundus photographs of each eye. A complete ophthalmologic examination was performed when indicated. The prevalence of monocular visual impairment (MVI) was 4.26% (95% CI, 3.66-4.95, n = 163). Amblyopia was the most common cause, accounting for 33%. The prevalence of amblyopia was 1.44% (95% CI, 1.01-1.81, n = 55), being higher among non-preschool vision screened persons compared to those who were offered (estimated 95% attendance) preschool vision screening (1.78%, n = 41, 95% CI 1.24-2.33 versus 0.44%, n = 2, 95% CI, 0.12-1.60, p = 0.024). The leading cause of amblyopia was anisometropia (45.5%, 25/55). Amblyopia was the most common cause of MVI. Following the initiation of the Danish national preschool vision screening programme, which has an approximate attendance rate of 95%, the prevalence of amblyopia decreased by fourfold. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  12. Short-Term Monocular Deprivation Enhances Physiological Pupillary Oscillations.

    Science.gov (United States)

    Binda, Paola; Lunghi, Claudia

    2017-01-01

    Short-term monocular deprivation alters visual perception in adult humans, increasing the dominance of the deprived eye, for example, as measured with binocular rivalry. This form of plasticity may depend upon the inhibition/excitation balance in the visual cortex. Recent work suggests that cortical excitability is reliably tracked by dilations and constrictions of the pupils of the eyes. Here, we ask whether monocular deprivation produces a systematic change of pupil behavior, as measured at rest, that is independent of the change of visual perception. During periods of minimal sensory stimulation (in the dark) and task requirements (minimizing body and gaze movements), slow pupil oscillations, "hippus," spontaneously appear. We find that hippus amplitude increases after monocular deprivation, with larger hippus changes in participants showing larger ocular dominance changes (measured by binocular rivalry). This tight correlation suggests that a single latent variable explains both the change of ocular dominance and hippus. We speculate that the neurotransmitter norepinephrine may be implicated in this phenomenon, given its important role in both plasticity and pupil control. On the practical side, our results indicate that measuring the pupil hippus (a simple and short procedure) provides a sensitive index of the change of ocular dominance induced by short-term monocular deprivation, hence a proxy for plasticity.

  13. Short-Term Monocular Deprivation Enhances Physiological Pupillary Oscillations

    Directory of Open Access Journals (Sweden)

    Paola Binda

    2017-01-01

    Full Text Available Short-term monocular deprivation alters visual perception in adult humans, increasing the dominance of the deprived eye, for example, as measured with binocular rivalry. This form of plasticity may depend upon the inhibition/excitation balance in the visual cortex. Recent work suggests that cortical excitability is reliably tracked by dilations and constrictions of the pupils of the eyes. Here, we ask whether monocular deprivation produces a systematic change of pupil behavior, as measured at rest, that is independent of the change of visual perception. During periods of minimal sensory stimulation (in the dark and task requirements (minimizing body and gaze movements, slow pupil oscillations, “hippus,” spontaneously appear. We find that hippus amplitude increases after monocular deprivation, with larger hippus changes in participants showing larger ocular dominance changes (measured by binocular rivalry. This tight correlation suggests that a single latent variable explains both the change of ocular dominance and hippus. We speculate that the neurotransmitter norepinephrine may be implicated in this phenomenon, given its important role in both plasticity and pupil control. On the practical side, our results indicate that measuring the pupil hippus (a simple and short procedure provides a sensitive index of the change of ocular dominance induced by short-term monocular deprivation, hence a proxy for plasticity.

  14. Artificial vision.

    Science.gov (United States)

    Zarbin, M; Montemagno, C; Leary, J; Ritch, R

    2011-09-01

    A number treatment options are emerging for patients with retinal degenerative disease, including gene therapy, trophic factor therapy, visual cycle inhibitors (e.g., for patients with Stargardt disease and allied conditions), and cell transplantation. A radically different approach, which will augment but not replace these options, is termed neural prosthetics ("artificial vision"). Although rewiring of inner retinal circuits and inner retinal neuronal degeneration occur in association with photoreceptor degeneration in retinitis pigmentosa (RP), it is possible to create visually useful percepts by stimulating retinal ganglion cells electrically. This fact has lead to the development of techniques to induce photosensitivity in cells that are not light sensitive normally as well as to the development of the bionic retina. Advances in artificial vision continue at a robust pace. These advances are based on the use of molecular engineering and nanotechnology to render cells light-sensitive, to target ion channels to the appropriate cell type (e.g., bipolar cell) and/or cell region (e.g., dendritic tree vs. soma), and on sophisticated image processing algorithms that take advantage of our knowledge of signal processing in the retina. Combined with advances in gene therapy, pathway-based therapy, and cell-based therapy, "artificial vision" technologies create a powerful armamentarium with which ophthalmologists will be able to treat blindness in patients who have a variety of degenerative retinal diseases.

  15. The Energy Spectrum of Ultra-High-Energy Cosmic Rays Measured by the Telescope Array FADC Fluorescence Detectors in Monocular Mode

    CERN Document Server

    Abu-Zayyad, T; Allen, M; Anderson, R; Azuma, R; Barcikowski, E; Belz, J W; Bergman, D R; Blake, S A; Cady, R; Cheon, B G; Chiba, J; Chikawa, M; Cho, E J; Cho, W R; Fujii, H; Fujii, T; Fukuda, T; Fukushima, M; Hanlon, W; Hayashi, K; Hayashi, Y; Hayashida, N; Hibino, K; Hiyama, K; Honda, K; Iguchi, T; Ikeda, D; Ikuta, K; Inoue, N; Ishii, T; Ishimori, R; Ito, H; Ivanov, D; Iwamoto, S; Jui, C C H; Kadota, K; Kakimoto, F; Kalashev, O; Kanbe, T; Kasahara, K; Kawai, H; Kawakami, S; Kawana, S; Kido, E; Kim, H B; Kim, H K; Kim, J H; Kitamoto, K; Kitamura, S; Kitamura, Y; Kobayashi, K; Kobayashi, Y; Kondo, Y; Kuramoto, K; Kuzmin, V; Kwon, Y J; Lan, J; Lim, S I; Lundquist, J P; Machida, S; Martens, K; Matsuda, T; Matsuura, T; Matsuyama, T; Matthews, J N; Myers, I; Minamino, M; Miyata, K; Murano, Y; Nagataki, S; Nakamura, T; Nam, S W; Nonaka, T; Ogio, S; Ogura, J; Ohnishi, M; Ohoka, H; Oki, K; Oku, D; Okuda, T; Ono, M; Oshima, A; Ozawa, S; Park, I H; Pshirkov, M S; Rodriguez, D C; Roh, S Y; Rubtsov, G; Ryu, D; Sagawa, H; Sakurai, N; Sampson, A L; Scott, L M; Shah, P D; Shibata, F; Shibata, T; Shimodaira, H; Shin, B K; Shin, J I; Shirahama, T; Smith, J D; Sokolsky, P; Sonley, T J; Springer, R W; Stokes, B T; Stratton, S R; Stroman, T A; Suzuki, S; Takahashi, Y; Takeda, M; Taketa, A; Takita, M; Tameda, Y; Tanaka, H; Tanaka, K; Tanaka, M; Thomas, S B; Thomson, G B; Tinyakov, P; Tkachev, I; Tokuno, H; Tomida, T; Troitsky, S; Tsunesada, Y; Tsutsumi, K; Tsuyuguchi, Y; Uchihori, Y; Udo, S; Ukai, H; Vasiloff, G; Wada, Y; Wong, T; Yamakawa, Y; Yamane, R; Yamaoka, H; Yamazaki, K; Yang, J; Yoneda, Y; Yoshida, S; Yoshii, H; Zollinger, R; Zundel, Z

    2013-01-01

    We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array's third fluorescence detector (Abu-Zayyad {\\it et al.}, {Astropart. Phys.} 39 (2012), 109). This combined spectrum corroborates the recently published Telescope Array surface detector spectrum (Abu-Zayyad {\\it et al.}, ...

  16. A Vision-Based System for Intelligent Monitoring: Human Behaviour Analysis and Privacy by Context

    Directory of Open Access Journals (Sweden)

    Alexandros Andre Chaaraoui

    2014-05-01

    Full Text Available Due to progress and demographic change, society is facing a crucial challenge related to increased life expectancy and a higher number of people in situations of dependency. As a consequence, there exists a significant demand for support systems for personal autonomy. This article outlines the vision@home project, whose goal is to extend independent living at home for elderly and impaired people, providing care and safety services by means of vision-based monitoring. Different kinds of ambient-assisted living services are supported, from the detection of home accidents, to telecare services. In this contribution, the specification of the system is presented, and novel contributions are made regarding human behaviour analysis and privacy protection. By means of a multi-view setup of cameras, people’s behaviour is recognised based on human action recognition. For this purpose, a weighted feature fusion scheme is proposed to learn from multiple views. In order to protect the right to privacy of the inhabitants when a remote connection occurs, a privacy-by-context method is proposed. The experimental results of the behaviour recognition method show an outstanding performance, as well as support for multi-view scenarios and real-time execution, which are required in order to provide the proposed services.

  17. Object Detection and Tracking Method of AUV Based on Acoustic Vision

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tie-dong; WAN Lei; ZENG Wen-jing; XU Yu-ru

    2012-01-01

    This paper describes a new framework for object detection and tracking of AUV including underwater acoustic data interpolation,underwater acoustic images segmentation and underwater objects tracking.This framework is applied to the design of vision-based method for AUV based on the forward looking sonar sensor.First,the real-time data flow (underwater acoustic images) is pre-processed to form the whole underwater acoustic image,and the relevant position information of objects is extracted and determined.An improved method of double threshold segmentation is proposed to resolve the problem that the threshold cannot be adjusted adaptively in the traditional method.Second,a representation of region information is created in light of the Gaussian particle filter.The weighted integration strategy combining the area and invariant moment is proposed to perfect the weight of particles and to enhance the tracking robustness.Results obtained on the real acoustic vision platform of AUV during sea trials are displayed and discussed.They show that the proposed method can detect and track the moving objects underwater online,and it is effective and robust.

  18. Endoscopic vision-based tracking of multiple surgical instruments during robot-assisted surgery.

    Science.gov (United States)

    Ryu, Jiwon; Choi, Jaesoon; Kim, Hee Chan

    2013-01-01

    Robot-assisted minimally invasive surgery is effective for operations in limited space. Enhancing safety based on automatic tracking of surgical instrument position to prevent inadvertent harmful events such as tissue perforation or instrument collisions could be a meaningful augmentation to current robotic surgical systems. A vision-based instrument tracking scheme as a core algorithm to implement such functions was developed in this study. An automatic tracking scheme is proposed as a chain of computer vision techniques, including classification of metallic properties using k-means clustering and instrument movement tracking using similarity measures, Euclidean distance calculations, and a Kalman filter algorithm. The implemented system showed satisfactory performance in tests using actual robot-assisted surgery videos. Trajectory comparisons of automatically detected data and ground truth data obtained by manually locating the center of mass of each instrument were used to quantitatively validate the system. Instruments and collisions could be well tracked through the proposed methods. The developed collision warning system could provide valuable information to clinicians for safer procedures.

  19. Vision correction for computer users based on image pre-compensation with changing pupil size.

    Science.gov (United States)

    Huang, Jian; Barreto, Armando; Alonso, Miguel; Adjouadi, Malek

    2011-01-01

    Many computer users suffer varying degrees of visual impairment, which hinder their interaction with computers. In contrast with available methods of vision correction (spectacles, contact lenses, LASIK, etc.), this paper proposes a vision correction method for computer users based on image pre-compensation. The blurring caused by visual aberration is counteracted through the pre-compensation performed on images displayed on the computer screen. The pre-compensation model used is based on the visual aberration of the user's eye, which can be measured by a wavefront analyzer. However, the aberration measured is associated with one specific pupil size. If the pupil has a different size during viewing of the pre-compensated images, the pre-compensation model should also be modified to sustain appropriate performance. In order to solve this problem, an adjustment of the wavefront function used for pre-compensation is implemented to match the viewing pupil size. The efficiency of these adjustments is evaluated with an "artificial eye" (high resolution camera). Results indicate that the adjustment used is successful and significantly improves the images perceived and recorded by the artificial eye.

  20. Object detection and tracking method of AUV based on acoustic vision

    Science.gov (United States)

    Zhang, Tie-dong; Wan, Lei; Zeng, Wen-jing; Xu, Yu-ru

    2012-12-01

    This paper describes a new framework for object detection and tracking of AUV including underwater acoustic data interpolation, underwater acoustic images segmentation and underwater objects tracking. This framework is applied to the design of vision-based method for AUV based on the forward looking sonar sensor. First, the real-time data flow (underwater acoustic images) is pre-processed to form the whole underwater acoustic image, and the relevant position information of objects is extracted and determined. An improved method of double threshold segmentation is proposed to resolve the problem that the threshold cannot be adjusted adaptively in the traditional method. Second, a representation of region information is created in light of the Gaussian particle filter. The weighted integration strategy combining the area and invariant moment is proposed to perfect the weight of particles and to enhance the tracking robustness. Results obtained on the real acoustic vision platform of AUV during sea trials are displayed and discussed. They show that the proposed method can detect and track the moving objects underwater online, and it is effective and robust.