AIM:To investigate the frequency and associated factors of accommodation and non-strabismic binocular vision dysfunction among medical university students.METHODS:Totally 158 student volunteers underwent routine visio...AIM:To investigate the frequency and associated factors of accommodation and non-strabismic binocular vision dysfunction among medical university students.METHODS:Totally 158 student volunteers underwent routine vision examination in the optometry clinic of Guangxi Medical University.Their data were used to identify the different types of accommodation and nonstrabismic binocular vision dysfunction and to determine their frequency.Correlation analysis and logistic regression were used to examine the factors associated with these abnormalities.RESULTS:The results showed that 36.71%of the subjects had accommodation and non-strabismic binocular vision issues,with 8.86%being attributed to accommodation dysfunction and 27.85%to binocular abnormalities.Convergence insufficiency(CI)was the most common abnormality,accounting for 13.29%.Those with these abnormalities experienced higher levels of eyestrain(χ2=69.518,P<0.001).The linear correlations were observed between the difference of binocular spherical equivalent(SE)and the index of horizontal esotropia at a distance(r=0.231,P=0.004)and the asthenopia survey scale(ASS)score(r=0.346,P<0.001).Furthermore,the right eye's SE was inversely correlated with the convergence of positive and negative fusion images at close range(r=-0.321,P<0.001),the convergence of negative fusion images at close range(r=-0.294,P<0.001),the vergence facility(VF;r=-0.234,P=0.003),and the set of negative fusion images at far range(r=-0.237,P=0.003).Logistic regression analysis indicated that gender,age,and the difference in right and binocular SE did not influence the emergence of these abnormalities.CONCLUSION:Binocular vision abnormalities are more prevalent than accommodation dysfunction,with CI being the most frequent type.Greater binocular refractive disparity leads to more severe eyestrain symptoms.展开更多
In nowadays society,the safety of the elderly population is becoming a pressing concern,especially for those who live alone.There might be daily risks such as accidental falling or treatment attack on them.Aiming at t...In nowadays society,the safety of the elderly population is becoming a pressing concern,especially for those who live alone.There might be daily risks such as accidental falling or treatment attack on them.Aiming at these problems,indoor positioning could be a critical way to monitor their states.With the rapidly development of the imaging techniques,wearable and portable cameras are very popular,which could be set on human individual.And in view of the advantages of the visual positioning,the authors propose a binocular visual positioning algorithm to real-timely locate the elderly indoor.In this paper,the imaging model has been established with the corrected image data from the binocular camera;then feature extraction has been completed to provide reference to adjacent image matching based on the binary robust independent elementary feature(BRIEF)descriptor,finally the camera movement and the states of the elderly have been estimated to distinguish their falling risk.In the experiments,the real-sense D435i sensors were adopted as the binocular cameras to obtain indoor images,and three experimental scenarios have been carried out to test the proposed method.The results show that the proposed algorithm can effectively locate the elderly indoor and improve the real-time monitoring capability.展开更多
AIM: To determine the association between the binocular vision and an abnormal head posture(AHP)when watching television(TV) in children 7-14 y of age.·METHODS: Fifty normal children in the normal group and 52 ch...AIM: To determine the association between the binocular vision and an abnormal head posture(AHP)when watching television(TV) in children 7-14 y of age.·METHODS: Fifty normal children in the normal group and 52 children with an AHP when watching TV in the AHP group were tested for spherical equivalents, far and near fusional convergence(FC) and fusional divergence(FD) amplitudes, near point of convergence, far and near heterophoria, accommodative convergence/accommodation ratio and stereoacuity. The values of these tests were compared between the two groups. The independent t test was applied at a confidence level of95%.·RESULTS: The far and near FC amplitudes and far FD amplitudes were lower in the AHP group(the far FC amplitudes: break point 13.6±5.4~△, recovery point 8.7±5.4~△.The near FC amplitudes: break point 14.5 ±7.3~△, recovery point 10. 3 ± 5. 1~△. The far FD amplitudes : break point3.9±2.7~△, recovery point 2.6±2.3~△) compared with those in the normal group(the far FC amplitudes: break point19.1 ±6.2△, recovery point 12.4 ±4.5~△. The near FC amplitudes: break point 22.3 ±8.0~△, recovery point 16.1 ±5.7~△. The far FD amplitudes: break point 7.0 ±2.1~△,recovery point 4.6 ±1.9~△). Other tests presented no statistically significant differences.·CONCLUSION: An association between the reduced FC and FD amplitudes and the AHP in children when watching TV is proposed in the study. This kind of AHP is considered to be an anomalous manifestation which appears in a part of puerile patients of fusional vergence dysfunction.展开更多
In order to improve the low positioning accuracy and execution efficiency of the robot binocular vision,a binocular vision positioning method based on coarse-fine stereo matching is proposed to achieve object position...In order to improve the low positioning accuracy and execution efficiency of the robot binocular vision,a binocular vision positioning method based on coarse-fine stereo matching is proposed to achieve object positioning.The random fern is used in the coarse matching to identify objects in the left and right images,and the pixel coordinates of the object center points in the two images are calculated to complete the center matching.In the fine matching,the right center point is viewed as an estimated value to set the search range of the right image,in which the region matching is implemented to find the best matched point of the left center point.Then,the similar triangle principle of the binocular vision model is used to calculate the 3D coordinates of the center point,achieving fast and accurate object positioning.Finally,the proposed method is applied to the object scene images and the robotic arm grasping platform.The experimental results show that the average absolute positioning error and average relative positioning error of the proposed method are 8.22 mm and 1.96%respectively when the object's depth distance is within 600 mm,the time consumption is less than 1.029s.The method can meet the needs of the robot grasping system,and has better accuracy and robustness.展开更多
In the process of field operation management,determining how to accurately realize crop row identification and path tracking control is an essential part of tractor automatic navigation.According to the linear operati...In the process of field operation management,determining how to accurately realize crop row identification and path tracking control is an essential part of tractor automatic navigation.According to the linear operation in the process of cotton field management,the tractor path tracking control system was designed based on binocular vision and the pure pursuit model.A new crop row detection method based on the Census transform and the PID control algorithm with dead zone were used.First,the upper computer software was developed by C++with the functions of parameter setting and image acquisition and processing.Second,an automatic steering controller was developed based on microprocessor MC9S12XS128 of Freescale.The control program was developed based on modular design using CodeWarrior during development of the PID-based automatic steering control strategy.Finally,a field experiment platform of tractor path tracking control was built,and field experiments under the actual cotton were conducted.The optimal visibility distance was determined by several previous experiments.When the tractor tracks the path with the optimal visibility distance in the growth environment of actual cotton crops,the mean absolute deviation of course angle was 0.95°,and the standard deviation was 1.26°;the mean absolute deviation of lateral position was 4.00 cm,and the standard deviation was 4.97 cm;the mean absolute deviation of front wheel angle was 2.99°,and the standard deviation was 3.67°.The experimental results show that(1)the crop row detection method based on Census transform can identify the crop line and plan the navigation path well,and(2)the tractor path tracking control system based on binocular vision has good stability and high control precision;thus,the control systemcan realize the automatic path tracking control of cotton line operation and meets the agricultural requirements of cotton field operation management.展开更多
Aiming at achieving complex moving targets perception,this paper designs a novel fusion-information detection and tracking system for moving targets.The system includes three modules:target detection,target tracking a...Aiming at achieving complex moving targets perception,this paper designs a novel fusion-information detection and tracking system for moving targets.The system includes three modules:target detection,target tracking and trajectory prediction.The target detection module can detect fast moving objects which can be used as a template.The target tracking module tracks the object and records its historical position.Finally,the trajectory prediction module can predict the trajectory of the moving object based on the historical position.After verification by the table tennis detection tracking and prediction binocular vision system,the system has high accuracy and speed in detection and tracking,and can basically meet the actual application needs.展开更多
In this paper,we consider eyes from the human binocular system,that simultaneously gaze on stationary point targets in space,while optimalal skipping from one target to the next,by rotaing their individual gaze drecto...In this paper,we consider eyes from the human binocular system,that simultaneously gaze on stationary point targets in space,while optimalal skipping from one target to the next,by rotaing their individual gaze drecton.The head is assume fixed on the torso and the rotaing gaze direction of the two eyes are assumed restricted to pass through a point in the visual space.It is further assumed that,individullly the rotations of the two eyes satisfy the well known Listing's law.We formulate and study acombined optimal gaze rotation for the two eyes,by constructing a single Riemanmian metric,on the asociaced parameter space.The goal is to optimally rotate so that the convergent gaze changes between two pre-specified target points in a finite time interval[0,1].The cost function we choose is the total energy,measured by the L2?norm,of the six extenal torques on the binocular system.The torque functions are synthesized by solving an associated*two-point boundary value problem.The paper demonstrates,via simulation,the shape of the optimal gaze trajectory of the focused point of the bin-ocular system.The Euclidean distance between the initial and the final point is compared to the arc:length of the optimal trajectory.The consumed energy.is computed for diferent eye movement chores and discussed in the paper.Via simulation we observe that certain eye movement maneuvers are energy fficicnt and demonstrate that the optimal external torque is a linear function in time.We also explore and conclude that spitting an arbitry opimal eye movement into optimal vergence and version components is not energy fficient although this is how the human oculomotor control seems to operate.Opimal gaze tajectories and opimal extermal torque functions reported in this paper is new.展开更多
Driver attention distraction(DAD)is a typical artificial factor traffic accident,and DAD monitoring can improve driving security.In this study,a method was developed for accurate DAD monitoring based on binocular visi...Driver attention distraction(DAD)is a typical artificial factor traffic accident,and DAD monitoring can improve driving security.In this study,a method was developed for accurate DAD monitoring based on binocular vision.A binocular vision system was built,and camera parameters of the system were calibrated based on Open CV.In the method,the driver’s facial image is obtained by using active infrared imaging technology and preprocessed to locate the eye positions.The connected component labeling algorithm for binary images is used to pinpoint the eye locations.The characteristic information of the eye pupils is extracted with the least-squares ellipse fitting algorithm,and the characteristic information of the Purkinje image is obtained with the Harris corner detection algorithm.A DAD warning model based on the binocular vision system was established to evaluate the attention state of the driver.展开更多
BACKGROUND Medical robot is a promising surgical tool,but no specific one has been designed for interventional treatment of chronic pain.We developed a computed tomography-image based navigation robot using a new regi...BACKGROUND Medical robot is a promising surgical tool,but no specific one has been designed for interventional treatment of chronic pain.We developed a computed tomography-image based navigation robot using a new registration method with binocular vision.This kind of robot is appropriate for minimal invasive interventional procedures and easy to operate.The feasibility,accuracy and stability of this new robot need to be tested.AIM To assess quantitatively the feasibility,accuracy and stability of the binocularstereo-vision-based navigation robot for minimally invasive interventional procedures.METHODS A box model was designed for assessing the accuracy for targets at different distances.Nine(three sets)lead spheres were embedded in the model as puncture goals.The entry-to-target distances were set 50 mm(short-distance),100 mm(medium-distance)and 150 mm(long-distance).Puncture procedure was repeated three times for each goal.The Euclidian error of each puncture was calculated and statistically analyzed.Three head phantoms were used to explore the clinical feasibility and stability.Three independent operators conducted foramen ovale placement on head phantoms(both sides)by freehand or under the guidance of robot(18 punctures with each method).The operation time,adjustment time and one-time success rate were recorded,and the two guidancemethods were compared.RESULTS On the box model,the mean puncture errors of navigation robot were 1.7±0.9 mm for the short-distance target,2.4±1.0 mm for the moderate target and 4.4±1.4 mm for the long-distance target.On the head phantom,no obvious differences in operation time and adjustment time were found among the three performers(P>0.05).The median adjustment time was significantly less under the guidance of the robot than under free hand.The one-time success rate was significantly higher with the robot(P<0.05).There was no obvious difference in operation time between the two methods(P>0.05).CONCLUSION In the laboratory environment,accuracy of binocular-stereo-vision-based navigation robot is acceptable for target at 100 mm depth or less.Compared with freehand,foramen ovale placement accuracy can be improved with robot guidance.展开更多
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 detecti...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.展开更多
This paper deals with a binocular 3-D computer vision system based on the hierarchicalmatching of edge features, Frei and Chen operator is used to extract the edge. The averagegradients of an image obtained by two iso...This paper deals with a binocular 3-D computer vision system based on the hierarchicalmatching of edge features, Frei and Chen operator is used to extract the edge. The averagegradients of an image obtained by two isotropic operators are non-equal quantized andthresholded in an angle, Edge features are extracted after passing a preemphasis transferfunction which can equalize, the noise affection. Binary edge images are decomposed into apyramid structure which is stored and searched using llliffe’s location method. Corre-sponding points are used to determine the range data using triangulation based on an improvedTrivedi’s formula. In calibration the authors set the optical axes of the two cameras parallelto simplify the calculation, A 3 rd order Householder transform is used to solve the compati-ble coupled equations.展开更多
The head mounted display (HMD) is widely used in virtual reality technology. In common HMD, however,the binocular disparity is set to an equal fixed value in the entire range of view. Such HMD systems have several sho...The head mounted display (HMD) is widely used in virtual reality technology. In common HMD, however,the binocular disparity is set to an equal fixed value in the entire range of view. Such HMD systems have several shortcomings when used for wide views. In this study, in order to realize a natural stereo sensation of HMD with wide view, we measure the characteristics of binocular stereo perception and binocular light perception. Results show that both the stereoacuity and light sensitivity decrease as the retina's eccentricity increases from fovea to pe riphery. However, the decrease of the stereoacuity is more rapid than that of the light sensitivity. These results suggest that the binocular disparity at the peripheral field should be small, otherwise double images would be observed instead of a stereo view. Based on the results we develop a relative binocular stereoacuity model which can be applied {or the design of HMD systems with wide view.展开更多
The binocular stereo vision is the lowest cost sensor for obtaining 3D information.Considering the weakness of long‐distance measurement and stability,the improvement of accuracy and stability of stereo vision is urg...The binocular stereo vision is the lowest cost sensor for obtaining 3D information.Considering the weakness of long‐distance measurement and stability,the improvement of accuracy and stability of stereo vision is urgently required for application of precision agriculture.To address the challenges of stereo vision long‐distance measurement and stable perception without hardware upgrade,inspired by hawk eyes,higher resolution perception and the adaptive HDR(High Dynamic Range)were introduced in this paper.Simulating the function from physiological structure of‘deep fovea’and‘shallow fovea’of hawk eye,the higher resolution reconstruction method in this paper was aimed at ac-curacy improving.Inspired by adjustment of pupils,the adaptive HDR method was proposed for high dynamic range optimisation and stable perception.In various light conditions,compared with default stereo vision,the accuracy of proposed algorithm was improved by 28.0%evaluated by error ratio,and the stability was improved by 26.56%by disparity accuracy.For fixed distance measurement,the maximum improvement was 78.6%by standard deviation.Based on the hawk‐eye‐inspired perception algorithm,the point cloud of orchard was improved both in quality and quantity.The hawk‐eye‐inspired perception algorithm contributed great advance in binocular 3D point cloud recon-struction in orchard navigation map.展开更多
AIM:To compare the vergence mechanisms between good and poor sleepers in university students.METHODS:A total of 64 university students were recruited in this study.The validated Malay version of Pittsburgh Sleep Quali...AIM:To compare the vergence mechanisms between good and poor sleepers in university students.METHODS:A total of 64 university students were recruited in this study.The validated Malay version of Pittsburgh Sleep Quality Index questionnaire(PSQI-M)was used to measure the participants’sleep quality over the past month.Participants were categorized as good sleepers(n=32)and poor sleepers(n=32)based on the PSQI-M scores.Heterophoria and fusional vergences were measured at distance and near.Mann-Whitney U test was used to compare heterophoria,negative fusional vergence(NFV),and positive fusional vergence(PFV)at distance and near between good and poor sleepers.Spearman correlation analysis was used to study the relationship between PSQI-M score and PFV at distance.RESULTS:Both distance and near heterophorias were not significantly different between good and poor sleepers(P>0.05).There was a difference in distance PFV(P<0.05)between good and poor sleepers,but not in distance NFV,near NFV,and near PFV(P>0.05).Distance PFV was negatively correlated with PSQI-M score(rs=-0.33,P<0.05).CONCLUSION:University students with poor sleep quality demonstrates a reduced ability to maintain fusion with increasing convergence demand at distance.Sleep quality assessment during binocular vision examination in university students is recommended.展开更多
基金Supported by the Innovat ion and Entrepreneurship Project for College Students of the First Affiliated Hospital of Guangxi Medical University in 2022 and the Development and Application of Appropriate Medical and Health Technologies in Guangxi(No.S2021093).
文摘AIM:To investigate the frequency and associated factors of accommodation and non-strabismic binocular vision dysfunction among medical university students.METHODS:Totally 158 student volunteers underwent routine vision examination in the optometry clinic of Guangxi Medical University.Their data were used to identify the different types of accommodation and nonstrabismic binocular vision dysfunction and to determine their frequency.Correlation analysis and logistic regression were used to examine the factors associated with these abnormalities.RESULTS:The results showed that 36.71%of the subjects had accommodation and non-strabismic binocular vision issues,with 8.86%being attributed to accommodation dysfunction and 27.85%to binocular abnormalities.Convergence insufficiency(CI)was the most common abnormality,accounting for 13.29%.Those with these abnormalities experienced higher levels of eyestrain(χ2=69.518,P<0.001).The linear correlations were observed between the difference of binocular spherical equivalent(SE)and the index of horizontal esotropia at a distance(r=0.231,P=0.004)and the asthenopia survey scale(ASS)score(r=0.346,P<0.001).Furthermore,the right eye's SE was inversely correlated with the convergence of positive and negative fusion images at close range(r=-0.321,P<0.001),the convergence of negative fusion images at close range(r=-0.294,P<0.001),the vergence facility(VF;r=-0.234,P=0.003),and the set of negative fusion images at far range(r=-0.237,P=0.003).Logistic regression analysis indicated that gender,age,and the difference in right and binocular SE did not influence the emergence of these abnormalities.CONCLUSION:Binocular vision abnormalities are more prevalent than accommodation dysfunction,with CI being the most frequent type.Greater binocular refractive disparity leads to more severe eyestrain symptoms.
基金This work was supported by the National Natural Science Foundation of China(No.61803203).
文摘In nowadays society,the safety of the elderly population is becoming a pressing concern,especially for those who live alone.There might be daily risks such as accidental falling or treatment attack on them.Aiming at these problems,indoor positioning could be a critical way to monitor their states.With the rapidly development of the imaging techniques,wearable and portable cameras are very popular,which could be set on human individual.And in view of the advantages of the visual positioning,the authors propose a binocular visual positioning algorithm to real-timely locate the elderly indoor.In this paper,the imaging model has been established with the corrected image data from the binocular camera;then feature extraction has been completed to provide reference to adjacent image matching based on the binary robust independent elementary feature(BRIEF)descriptor,finally the camera movement and the states of the elderly have been estimated to distinguish their falling risk.In the experiments,the real-sense D435i sensors were adopted as the binocular cameras to obtain indoor images,and three experimental scenarios have been carried out to test the proposed method.The results show that the proposed algorithm can effectively locate the elderly indoor and improve the real-time monitoring capability.
基金Supported by the Scientific and Technological Project of Henan Scientific Committee(No.112102310193No.122102310132+2 种基金No.132102310132)the Key Scientific Research Project of Education Department of HenanProvince(No.12A320068)the Medical Science Research Project of Henan Province(No.201003112)
文摘AIM: To determine the association between the binocular vision and an abnormal head posture(AHP)when watching television(TV) in children 7-14 y of age.·METHODS: Fifty normal children in the normal group and 52 children with an AHP when watching TV in the AHP group were tested for spherical equivalents, far and near fusional convergence(FC) and fusional divergence(FD) amplitudes, near point of convergence, far and near heterophoria, accommodative convergence/accommodation ratio and stereoacuity. The values of these tests were compared between the two groups. The independent t test was applied at a confidence level of95%.·RESULTS: The far and near FC amplitudes and far FD amplitudes were lower in the AHP group(the far FC amplitudes: break point 13.6±5.4~△, recovery point 8.7±5.4~△.The near FC amplitudes: break point 14.5 ±7.3~△, recovery point 10. 3 ± 5. 1~△. The far FD amplitudes : break point3.9±2.7~△, recovery point 2.6±2.3~△) compared with those in the normal group(the far FC amplitudes: break point19.1 ±6.2△, recovery point 12.4 ±4.5~△. The near FC amplitudes: break point 22.3 ±8.0~△, recovery point 16.1 ±5.7~△. The far FD amplitudes: break point 7.0 ±2.1~△,recovery point 4.6 ±1.9~△). Other tests presented no statistically significant differences.·CONCLUSION: An association between the reduced FC and FD amplitudes and the AHP in children when watching TV is proposed in the study. This kind of AHP is considered to be an anomalous manifestation which appears in a part of puerile patients of fusional vergence dysfunction.
基金supported by National Natural Science Foundation of China(No.61125101)。
文摘In order to improve the low positioning accuracy and execution efficiency of the robot binocular vision,a binocular vision positioning method based on coarse-fine stereo matching is proposed to achieve object positioning.The random fern is used in the coarse matching to identify objects in the left and right images,and the pixel coordinates of the object center points in the two images are calculated to complete the center matching.In the fine matching,the right center point is viewed as an estimated value to set the search range of the right image,in which the region matching is implemented to find the best matched point of the left center point.Then,the similar triangle principle of the binocular vision model is used to calculate the 3D coordinates of the center point,achieving fast and accurate object positioning.Finally,the proposed method is applied to the object scene images and the robotic arm grasping platform.The experimental results show that the average absolute positioning error and average relative positioning error of the proposed method are 8.22 mm and 1.96%respectively when the object's depth distance is within 600 mm,the time consumption is less than 1.029s.The method can meet the needs of the robot grasping system,and has better accuracy and robustness.
基金supported by the National Key Research and Development Program(No.2017YFD0700400-2017YFD0700403).
文摘In the process of field operation management,determining how to accurately realize crop row identification and path tracking control is an essential part of tractor automatic navigation.According to the linear operation in the process of cotton field management,the tractor path tracking control system was designed based on binocular vision and the pure pursuit model.A new crop row detection method based on the Census transform and the PID control algorithm with dead zone were used.First,the upper computer software was developed by C++with the functions of parameter setting and image acquisition and processing.Second,an automatic steering controller was developed based on microprocessor MC9S12XS128 of Freescale.The control program was developed based on modular design using CodeWarrior during development of the PID-based automatic steering control strategy.Finally,a field experiment platform of tractor path tracking control was built,and field experiments under the actual cotton were conducted.The optimal visibility distance was determined by several previous experiments.When the tractor tracks the path with the optimal visibility distance in the growth environment of actual cotton crops,the mean absolute deviation of course angle was 0.95°,and the standard deviation was 1.26°;the mean absolute deviation of lateral position was 4.00 cm,and the standard deviation was 4.97 cm;the mean absolute deviation of front wheel angle was 2.99°,and the standard deviation was 3.67°.The experimental results show that(1)the crop row detection method based on Census transform can identify the crop line and plan the navigation path well,and(2)the tractor path tracking control system based on binocular vision has good stability and high control precision;thus,the control systemcan realize the automatic path tracking control of cotton line operation and meets the agricultural requirements of cotton field operation management.
基金the National Key Research and Development Program of China(2018YFB1305001)。
文摘Aiming at achieving complex moving targets perception,this paper designs a novel fusion-information detection and tracking system for moving targets.The system includes three modules:target detection,target tracking and trajectory prediction.The target detection module can detect fast moving objects which can be used as a template.The target tracking module tracks the object and records its historical position.Finally,the trajectory prediction module can predict the trajectory of the moving object based on the historical position.After verification by the table tennis detection tracking and prediction binocular vision system,the system has high accuracy and speed in detection and tracking,and can basically meet the actual application needs.
文摘In this paper,we consider eyes from the human binocular system,that simultaneously gaze on stationary point targets in space,while optimalal skipping from one target to the next,by rotaing their individual gaze drecton.The head is assume fixed on the torso and the rotaing gaze direction of the two eyes are assumed restricted to pass through a point in the visual space.It is further assumed that,individullly the rotations of the two eyes satisfy the well known Listing's law.We formulate and study acombined optimal gaze rotation for the two eyes,by constructing a single Riemanmian metric,on the asociaced parameter space.The goal is to optimally rotate so that the convergent gaze changes between two pre-specified target points in a finite time interval[0,1].The cost function we choose is the total energy,measured by the L2?norm,of the six extenal torques on the binocular system.The torque functions are synthesized by solving an associated*two-point boundary value problem.The paper demonstrates,via simulation,the shape of the optimal gaze trajectory of the focused point of the bin-ocular system.The Euclidean distance between the initial and the final point is compared to the arc:length of the optimal trajectory.The consumed energy.is computed for diferent eye movement chores and discussed in the paper.Via simulation we observe that certain eye movement maneuvers are energy fficicnt and demonstrate that the optimal external torque is a linear function in time.We also explore and conclude that spitting an arbitry opimal eye movement into optimal vergence and version components is not energy fficient although this is how the human oculomotor control seems to operate.Opimal gaze tajectories and opimal extermal torque functions reported in this paper is new.
基金This work is supported by the National Natural Science Foundation of China(51605215)Research Foundation of Nanjing Institute of Technology(QKJ201707)Qing Lan Project。
文摘Driver attention distraction(DAD)is a typical artificial factor traffic accident,and DAD monitoring can improve driving security.In this study,a method was developed for accurate DAD monitoring based on binocular vision.A binocular vision system was built,and camera parameters of the system were calibrated based on Open CV.In the method,the driver’s facial image is obtained by using active infrared imaging technology and preprocessed to locate the eye positions.The connected component labeling algorithm for binary images is used to pinpoint the eye locations.The characteristic information of the eye pupils is extracted with the least-squares ellipse fitting algorithm,and the characteristic information of the Purkinje image is obtained with the Harris corner detection algorithm.A DAD warning model based on the binocular vision system was established to evaluate the attention state of the driver.
基金Supported by Jiangsu Provincial Department of Science and Technology,No.BE2017603 and No.BE2017675。
文摘BACKGROUND Medical robot is a promising surgical tool,but no specific one has been designed for interventional treatment of chronic pain.We developed a computed tomography-image based navigation robot using a new registration method with binocular vision.This kind of robot is appropriate for minimal invasive interventional procedures and easy to operate.The feasibility,accuracy and stability of this new robot need to be tested.AIM To assess quantitatively the feasibility,accuracy and stability of the binocularstereo-vision-based navigation robot for minimally invasive interventional procedures.METHODS A box model was designed for assessing the accuracy for targets at different distances.Nine(three sets)lead spheres were embedded in the model as puncture goals.The entry-to-target distances were set 50 mm(short-distance),100 mm(medium-distance)and 150 mm(long-distance).Puncture procedure was repeated three times for each goal.The Euclidian error of each puncture was calculated and statistically analyzed.Three head phantoms were used to explore the clinical feasibility and stability.Three independent operators conducted foramen ovale placement on head phantoms(both sides)by freehand or under the guidance of robot(18 punctures with each method).The operation time,adjustment time and one-time success rate were recorded,and the two guidancemethods were compared.RESULTS On the box model,the mean puncture errors of navigation robot were 1.7±0.9 mm for the short-distance target,2.4±1.0 mm for the moderate target and 4.4±1.4 mm for the long-distance target.On the head phantom,no obvious differences in operation time and adjustment time were found among the three performers(P>0.05).The median adjustment time was significantly less under the guidance of the robot than under free hand.The one-time success rate was significantly higher with the robot(P<0.05).There was no obvious difference in operation time between the two methods(P>0.05).CONCLUSION In the laboratory environment,accuracy of binocular-stereo-vision-based navigation robot is acceptable for target at 100 mm depth or less.Compared with freehand,foramen ovale placement accuracy can be improved with robot guidance.
文摘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.
文摘This paper deals with a binocular 3-D computer vision system based on the hierarchicalmatching of edge features, Frei and Chen operator is used to extract the edge. The averagegradients of an image obtained by two isotropic operators are non-equal quantized andthresholded in an angle, Edge features are extracted after passing a preemphasis transferfunction which can equalize, the noise affection. Binary edge images are decomposed into apyramid structure which is stored and searched using llliffe’s location method. Corre-sponding points are used to determine the range data using triangulation based on an improvedTrivedi’s formula. In calibration the authors set the optical axes of the two cameras parallelto simplify the calculation, A 3 rd order Householder transform is used to solve the compati-ble coupled equations.
文摘The head mounted display (HMD) is widely used in virtual reality technology. In common HMD, however,the binocular disparity is set to an equal fixed value in the entire range of view. Such HMD systems have several shortcomings when used for wide views. In this study, in order to realize a natural stereo sensation of HMD with wide view, we measure the characteristics of binocular stereo perception and binocular light perception. Results show that both the stereoacuity and light sensitivity decrease as the retina's eccentricity increases from fovea to pe riphery. However, the decrease of the stereoacuity is more rapid than that of the light sensitivity. These results suggest that the binocular disparity at the peripheral field should be small, otherwise double images would be observed instead of a stereo view. Based on the results we develop a relative binocular stereoacuity model which can be applied {or the design of HMD systems with wide view.
基金funded by the National Natural Science Foundation of China(No.51979275)Key Laboratory of Spatial‐temporal Big Data Analysis and Application of Nat-ural Resources in Megacities,MNR(No.KFKT‐2022‐05)+3 种基金Open Fund of Key Laboratory of Urban Land Resources Monitoring and Simulation,Ministry of Natural Resources(No.KF‐2021‐06‐115)Open Project Program of State Key Laboratory of Virtual Reality Technology and Systems,Bei-hang University(No.VRLAB2022C10)Jiangsu Province and Education Ministry Co‐sponsored Synergistic Innovation Center of Modern Agricultural Equipment(No.XTCX2002)2115 Talent Development Program of China Agricultural University and Chinese Universities Scientific Fund(No.2021TC105).
文摘The binocular stereo vision is the lowest cost sensor for obtaining 3D information.Considering the weakness of long‐distance measurement and stability,the improvement of accuracy and stability of stereo vision is urgently required for application of precision agriculture.To address the challenges of stereo vision long‐distance measurement and stable perception without hardware upgrade,inspired by hawk eyes,higher resolution perception and the adaptive HDR(High Dynamic Range)were introduced in this paper.Simulating the function from physiological structure of‘deep fovea’and‘shallow fovea’of hawk eye,the higher resolution reconstruction method in this paper was aimed at ac-curacy improving.Inspired by adjustment of pupils,the adaptive HDR method was proposed for high dynamic range optimisation and stable perception.In various light conditions,compared with default stereo vision,the accuracy of proposed algorithm was improved by 28.0%evaluated by error ratio,and the stability was improved by 26.56%by disparity accuracy.For fixed distance measurement,the maximum improvement was 78.6%by standard deviation.Based on the hawk‐eye‐inspired perception algorithm,the point cloud of orchard was improved both in quality and quantity.The hawk‐eye‐inspired perception algorithm contributed great advance in binocular 3D point cloud recon-struction in orchard navigation map.
文摘AIM:To compare the vergence mechanisms between good and poor sleepers in university students.METHODS:A total of 64 university students were recruited in this study.The validated Malay version of Pittsburgh Sleep Quality Index questionnaire(PSQI-M)was used to measure the participants’sleep quality over the past month.Participants were categorized as good sleepers(n=32)and poor sleepers(n=32)based on the PSQI-M scores.Heterophoria and fusional vergences were measured at distance and near.Mann-Whitney U test was used to compare heterophoria,negative fusional vergence(NFV),and positive fusional vergence(PFV)at distance and near between good and poor sleepers.Spearman correlation analysis was used to study the relationship between PSQI-M score and PFV at distance.RESULTS:Both distance and near heterophorias were not significantly different between good and poor sleepers(P>0.05).There was a difference in distance PFV(P<0.05)between good and poor sleepers,but not in distance NFV,near NFV,and near PFV(P>0.05).Distance PFV was negatively correlated with PSQI-M score(rs=-0.33,P<0.05).CONCLUSION:University students with poor sleep quality demonstrates a reduced ability to maintain fusion with increasing convergence demand at distance.Sleep quality assessment during binocular vision examination in university students is recommended.
