Four-dimensional trajectory based operation(4D-TBO)is believed to enhance the planning and execution of efficient flights,reduce potential conflicts and resolve upcoming tremendous flight demand.Most of the 4D traject...Four-dimensional trajectory based operation(4D-TBO)is believed to enhance the planning and execution of efficient flights,reduce potential conflicts and resolve upcoming tremendous flight demand.Most of the 4D trajectory planning related studies have focused on manned aircraft instead of unmanned aerial vehicles(UAVs).This paper focuses on planning conflict-free 4D trajectories for fixed-wing UAVs before the departure or during the flight planning.A 4D trajectory generation technique based on Tau theory is developed,which can incorporate the time constraints over the waypoint sequence in the flight plan.Then the 4D trajectory is optimized by the particle swarm optimization(PSO)algorithm.Further simulations are performed to demonstrate the effectiveness of the proposed method,which would offer a good chance for integrating UAV into civil airspace in the future.展开更多
In three-dimensional displays,large vertical parallax in parallax images is disadvantageous to stereo vision due to the presence of visual fatigue.Based on the principle that homologous points in different parallax im...In three-dimensional displays,large vertical parallax in parallax images is disadvantageous to stereo vision due to the presence of visual fatigue.Based on the principle that homologous points in different parallax images correspond to the same object point,a method is proposed to eliminate the vertical parallax in multi-view parallax images.The coordinate mapping relationship between a standard parallax image and an awaiting rectification parallax image is established according to the coordinates of the image points of the rectangular calibration board vertices.Experiments are conducted,and results prove that the proposed method is reliable.展开更多
A method to reduce crosstalk in multi-view autostereoscopic three-dimensional （3D） displays based on the lenticular sheet is proposed. Correcting the luminance values of each parallax image displayed on the display ...A method to reduce crosstalk in multi-view autostereoscopic three-dimensional （3D） displays based on the lenticular sheet is proposed. Correcting the luminance values of each parallax image displayed on the display screen is employed. We analyze the causes of crosstalk. We deduce the formulas of crosstalk reduction according to the relationship between crosstalk coefficients of each parallax image observed through the lenticular sheet, luminance values of each parallax image displayed on the display screen, and luminance values of each parallax image observed through the lenticular sheet at each viewing position. Experimental results verify the effectiveness of the proposed method.展开更多
We propose a method of generating orthoscopic elemental image array from a sparse camera array.A parallax image array obtained by a sparse camera array provides different perspectives of a real three-dimensional（3D）...We propose a method of generating orthoscopic elemental image array from a sparse camera array.A parallax image array obtained by a sparse camera array provides different perspectives of a real three-dimensional（3D） scene,and has all the information the elemental image array needs.In-depth analysis of the generation method and the relationships between the sparse camera array and the elemental image array are presented.The experimental results demonstrate the correctness of the proposed method.展开更多
A crosstalk-free integral imaging display consisting of a display panel and double piano-convex micro-lens array is proposed. The double piano-convex micro-lens array includes two micro-lens arrays, A and B. Micro-len...A crosstalk-free integral imaging display consisting of a display panel and double piano-convex micro-lens array is proposed. The double piano-convex micro-lens array includes two micro-lens arrays, A and B. Micro-lens array A is used to eliminate crosstalk by completely reflecting crosstalk lights. Micro-lens array B, located near microqens array A, is used to display three-dimensional images. Computer simulations based on ray-tracing are conducted. Crosstalk-free reconstruction images may be clearly observed from the simulation results.展开更多
We propose an autostereoscopic three-dimensional （3D） projection display. The display consists of four projectors, a projection screen, and two lenticular sheets. The operation principle and calculation equations ar...We propose an autostereoscopic three-dimensional （3D） projection display. The display consists of four projectors, a projection screen, and two lenticular sheets. The operation principle and calculation equations are described in detail and the parallax images are corrected by means of homography. A 50-inch autostereoscopic 3D projection display prototype is developed. The normalized luminance distributions of viewing zones from the simulation and the measurement are given. Results agree well with the designed values. The proposed prototype presents full-resolution 3D images similar to the conventional prototype based on two parallax barriers. Moreover, the proposed prototype shows considerably higher brightness and efficiency of light utilization.展开更多
One-dimensional （ID） integral imaging based on parallax images＇ virtual reconstruction is proposed. The 1D integral imaging contains parallax images＇ capture process, parallax images＇ virtual reconstruction proce...One-dimensional （ID） integral imaging based on parallax images＇ virtual reconstruction is proposed. The 1D integral imaging contains parallax images＇ capture process, parallax images＇ virtual reconstruction process, and ID elemental image array＇s generation process. A pixel mapping algorithm is deduced to implement the last two processes; a ID elemental image array is generated by the mapping of pixels on the parallax images obtained using a ID camera array. The proposed ID integral imaging can capture the ID elemental image array of a real three-dimensional （3D） scene.展开更多
Accurate head poses are useful for many face-related tasks such as face recognition, gaze estimation,and emotion analysis. Most existing methods estimate head poses that are included in the training data(i.e.,previous...Accurate head poses are useful for many face-related tasks such as face recognition, gaze estimation,and emotion analysis. Most existing methods estimate head poses that are included in the training data(i.e.,previously seen head poses). To predict head poses that are not seen in the training data, some regression-based methods have been proposed. However, they focus on estimating continuous head pose angles, and thus do not systematically evaluate the performance on predicting unseen head poses. In this paper, we use a dense multivariate label distribution(MLD) to represent the pose angle of a face image. By incorporating both seen and unseen pose angles into MLD, the head pose predictor can estimate unseen head poses with an accuracy comparable to that of estimating seen head poses. On the Pointing'04 database, the mean absolute errors of results for yaw and pitch are 4.01?and 2.13?, respectively. In addition, experiments on the CAS-PEAL and CMU Multi-PIE databases show that the proposed dense MLD-based head pose estimation method can obtain the state-of-the-art performance when compared to some existing methods.展开更多
In this letter, we propose a voltage-controlled optical filter based on electrowetting. The device is made of a transparent cubic cell filled with two immiscible liquids having three indium tin oxide electrodes fabric...In this letter, we propose a voltage-controlled optical filter based on electrowetting. The device is made of a transparent cubic cell filled with two immiscible liquids having three indium tin oxide electrodes fabricated on the bottom substrate of the cell. A conductive droplet carrying a color filter is placed on the ITO electrode and the surrounding liquid is density-matched silicone oil. Under zero bias, the droplet is placed in the middle of tile substrate and white light passes through the filter and we can see red light on the screen. When a voltage is applied to the device, the filter moves with the liquid based on electrowetting effect, we can see the white light on the screen. Due to the movement of the liqnid, our device functions as an optical switcher. The switch trine of the device is -70 ms. The proposed device has a wide application in optical communication. electronic display, and optical switch.展开更多
Integral imaging is a true,three-dimensional（3D） display technology that captures and reconstructs 3D scenes using two-dimensional（2D） micro-lens arrays.The manufacturing technique of micro-lens arrays is complica...Integral imaging is a true,three-dimensional（3D） display technology that captures and reconstructs 3D scenes using two-dimensional（2D） micro-lens arrays.The manufacturing technique of micro-lens arrays is complicated and expensive,thus limiting the application of the technology.An imitating micro-lens array for integral imaging is presented in this letter.Imitating micro-lens array is composed of a cheap lenticular lens and a parallax barrier.The relationship of the parameters of the imitating micro-lens array is analyzed and the parameter formulae are deduced.The arrangement of pixels under a cell of the imitating micro-lens array is presented.The imitating micro-lens array is simulated using ASAP software,and the results prove that the designed imitating micro-lens array is effective.A 3D scene is reconstructed on a 3D display that consists of the imitating micro-lens array and a 17-inch flat panel display.展开更多
A polymer-stabilized blue phase liquid crystal display （BPLCD） with slanted wall-shaped electrodes is proposed. Compared with the traditional BPLCD with wall-shaped electrodes, the electrodes of the proposed BPLCD a...A polymer-stabilized blue phase liquid crystal display （BPLCD） with slanted wall-shaped electrodes is proposed. Compared with the traditional BPLCD with wall-shaped electrodes, the electrodes of the proposed BPLCD are slightly angled to obtain phase retardation in the entire cell even at the position of electrodes. The proposed BPLCD demonstrates a relatively higher average transmittance and overall brightness than the traditional BPLCD.展开更多
文摘Four-dimensional trajectory based operation(4D-TBO)is believed to enhance the planning and execution of efficient flights,reduce potential conflicts and resolve upcoming tremendous flight demand.Most of the 4D trajectory planning related studies have focused on manned aircraft instead of unmanned aerial vehicles(UAVs).This paper focuses on planning conflict-free 4D trajectories for fixed-wing UAVs before the departure or during the flight planning.A 4D trajectory generation technique based on Tau theory is developed,which can incorporate the time constraints over the waypoint sequence in the flight plan.Then the 4D trajectory is optimized by the particle swarm optimization(PSO)algorithm.Further simulations are performed to demonstrate the effectiveness of the proposed method,which would offer a good chance for integrating UAV into civil airspace in the future.
基金supported by the National Natural Science Foundation of China under Grant No. 60877004
文摘In three-dimensional displays,large vertical parallax in parallax images is disadvantageous to stereo vision due to the presence of visual fatigue.Based on the principle that homologous points in different parallax images correspond to the same object point,a method is proposed to eliminate the vertical parallax in multi-view parallax images.The coordinate mapping relationship between a standard parallax image and an awaiting rectification parallax image is established according to the coordinates of the image points of the rectangular calibration board vertices.Experiments are conducted,and results prove that the proposed method is reliable.
基金supported by the National Natural Science Foundation of China under Grant No. 60877004
文摘A method to reduce crosstalk in multi-view autostereoscopic three-dimensional （3D） displays based on the lenticular sheet is proposed. Correcting the luminance values of each parallax image displayed on the display screen is employed. We analyze the causes of crosstalk. We deduce the formulas of crosstalk reduction according to the relationship between crosstalk coefficients of each parallax image observed through the lenticular sheet, luminance values of each parallax image displayed on the display screen, and luminance values of each parallax image observed through the lenticular sheet at each viewing position. Experimental results verify the effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China under Grant No. 61036008
文摘We propose a method of generating orthoscopic elemental image array from a sparse camera array.A parallax image array obtained by a sparse camera array provides different perspectives of a real three-dimensional（3D） scene,and has all the information the elemental image array needs.In-depth analysis of the generation method and the relationships between the sparse camera array and the elemental image array are presented.The experimental results demonstrate the correctness of the proposed method.
基金supported by the National "973" Program of China (No. 2013CB328802)the National Natural Science Foundation of China (Nos. 61036008 and61225022)the National "863" Program of China(No. 2012AA011901)
文摘A crosstalk-free integral imaging display consisting of a display panel and double piano-convex micro-lens array is proposed. The double piano-convex micro-lens array includes two micro-lens arrays, A and B. Micro-lens array A is used to eliminate crosstalk by completely reflecting crosstalk lights. Micro-lens array B, located near microqens array A, is used to display three-dimensional images. Computer simulations based on ray-tracing are conducted. Crosstalk-free reconstruction images may be clearly observed from the simulation results.
基金supported by the National Natural Science Foundation of China under Grant Nos.60877004and 61036008
文摘We propose an autostereoscopic three-dimensional （3D） projection display. The display consists of four projectors, a projection screen, and two lenticular sheets. The operation principle and calculation equations are described in detail and the parallax images are corrected by means of homography. A 50-inch autostereoscopic 3D projection display prototype is developed. The normalized luminance distributions of viewing zones from the simulation and the measurement are given. Results agree well with the designed values. The proposed prototype presents full-resolution 3D images similar to the conventional prototype based on two parallax barriers. Moreover, the proposed prototype shows considerably higher brightness and efficiency of light utilization.
基金supported by the National Natural Science Foundation of China(No.61036008)the National "863" Program of China(No.2012AA011901)the International Science and Technology Cooperation Program of China(No.2012DFG11610)
文摘One-dimensional （ID） integral imaging based on parallax images＇ virtual reconstruction is proposed. The 1D integral imaging contains parallax images＇ capture process, parallax images＇ virtual reconstruction process, and ID elemental image array＇s generation process. A pixel mapping algorithm is deduced to implement the last two processes; a ID elemental image array is generated by the mapping of pixels on the parallax images obtained using a ID camera array. The proposed ID integral imaging can capture the ID elemental image array of a real three-dimensional （3D） scene.
基金supported by the National Key Scientific Instrument and Equipment Development Project of China(No.2013YQ49087903)the National Natural Science Foundation of China(No.61202160)
文摘Accurate head poses are useful for many face-related tasks such as face recognition, gaze estimation,and emotion analysis. Most existing methods estimate head poses that are included in the training data(i.e.,previously seen head poses). To predict head poses that are not seen in the training data, some regression-based methods have been proposed. However, they focus on estimating continuous head pose angles, and thus do not systematically evaluate the performance on predicting unseen head poses. In this paper, we use a dense multivariate label distribution(MLD) to represent the pose angle of a face image. By incorporating both seen and unseen pose angles into MLD, the head pose predictor can estimate unseen head poses with an accuracy comparable to that of estimating seen head poses. On the Pointing'04 database, the mean absolute errors of results for yaw and pitch are 4.01?and 2.13?, respectively. In addition, experiments on the CAS-PEAL and CMU Multi-PIE databases show that the proposed dense MLD-based head pose estimation method can obtain the state-of-the-art performance when compared to some existing methods.
基金supported by the National Natural Science Foundation of China(Nos.61225022 and 61320106015)the National "973" Program of China(No.2013CB328802)+1 种基金the National "863" Program of China(No.2012AA011901)the Research Program of Sichuan Province,China(No.2013TD0002)
文摘In this letter, we propose a voltage-controlled optical filter based on electrowetting. The device is made of a transparent cubic cell filled with two immiscible liquids having three indium tin oxide electrodes fabricated on the bottom substrate of the cell. A conductive droplet carrying a color filter is placed on the ITO electrode and the surrounding liquid is density-matched silicone oil. Under zero bias, the droplet is placed in the middle of tile substrate and white light passes through the filter and we can see red light on the screen. When a voltage is applied to the device, the filter moves with the liquid based on electrowetting effect, we can see the white light on the screen. Due to the movement of the liqnid, our device functions as an optical switcher. The switch trine of the device is -70 ms. The proposed device has a wide application in optical communication. electronic display, and optical switch.
基金supported by the National Natural Science Foundation of China under Grant No.60877004.
文摘Integral imaging is a true,three-dimensional（3D） display technology that captures and reconstructs 3D scenes using two-dimensional（2D） micro-lens arrays.The manufacturing technique of micro-lens arrays is complicated and expensive,thus limiting the application of the technology.An imitating micro-lens array for integral imaging is presented in this letter.Imitating micro-lens array is composed of a cheap lenticular lens and a parallax barrier.The relationship of the parameters of the imitating micro-lens array is analyzed and the parameter formulae are deduced.The arrangement of pixels under a cell of the imitating micro-lens array is presented.The imitating micro-lens array is simulated using ASAP software,and the results prove that the designed imitating micro-lens array is effective.A 3D scene is reconstructed on a 3D display that consists of the imitating micro-lens array and a 17-inch flat panel display.
基金supported by the National Natural Science Foundation of China under Nos. 60877004 and 61036008
文摘A polymer-stabilized blue phase liquid crystal display （BPLCD） with slanted wall-shaped electrodes is proposed. Compared with the traditional BPLCD with wall-shaped electrodes, the electrodes of the proposed BPLCD are slightly angled to obtain phase retardation in the entire cell even at the position of electrodes. The proposed BPLCD demonstrates a relatively higher average transmittance and overall brightness than the traditional BPLCD.
