Structural colors based on metasurfaces have very promising applications in areas such as optical image encryption and color printing.Herein,we propose a deep learning-enabled reverse design of polarization-selective ...Structural colors based on metasurfaces have very promising applications in areas such as optical image encryption and color printing.Herein,we propose a deep learning-enabled reverse design of polarization-selective structural color based on coding metasurface.In this study,the long short-term memory(LSTM)neural network is presented to enable the forward and inverse mapping between coding metasurface structure and corresponding color.The results show that the method can achieve 98%accuracy for the forward prediction of color and 93%accuracy for the inverse design of the structure.Moreover,a cascaded architecture is adopted to train the inverse neural network model,which can solve the nonuniqueness problem of the polarization-selective color reverse design.This study provides a new path for the application and development of structural colors.展开更多
Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface ho...Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface holography can only realize static manipulation.In this study,we propose and demonstrate a multiplexing metasurface technique combined with multiwavelength code-division multiplexing(CDM)to realize dynamic manipulation.Multicolor code references are utilized to record information within a single metasurface and increase the information capacity and security for anticracks.A total of 48 monochrome images consisting of pure color characters and multilevel color video frames were reconstructed in dual polarization channels of the birefringent metasurface to exhibit high information density,and a video was displayed via sequential illumination of the corresponding code patterns to verify the ability of dynamic manipulation.Our approach demonstrates significant application potential in optical data storage,optical encryption,multiwavelengthversatile diffractive optical elements,and stimulated emission depletion microscopy.展开更多
We propose a new full color ghost imaging scheme using both time and code division multiplexing technologies.In the scheme,the speckle patterns of three colors(red,green and blue)are modulated with different time slot...We propose a new full color ghost imaging scheme using both time and code division multiplexing technologies.In the scheme,the speckle patterns of three colors(red,green and blue)are modulated with different time slots and codes.The light intensity is sampled by one bucket detector.Then based on the modulated time slots and codes,we can effectively and simultaneously extract three detection component signals corresponding to three color components of objects from the sampling signal of the bucket detector.Finally,three component images resulting from the three component detection signals can be synthesized into a full color image.The experimental results verify the feasibility of our scheme under the limit of the number of time slots and codes.Moreover,our scheme reduces the number of bucket detectors and can realize high quality imaging even in a noisy environment.展开更多
A novel color compensation method for multi-view video coding (MVC) is proposed, which efficiently exploits the inter-view dependencies between views with the existence of color mismatch caused by the diversity of cam...A novel color compensation method for multi-view video coding (MVC) is proposed, which efficiently exploits the inter-view dependencies between views with the existence of color mismatch caused by the diversity of cameras. A color compensation model is developed in RGB channels and then extended to YCbCr channels for practical use. A modified inter-view reference picture is constructed based on the color compensation model, which is more similar to the coding picture than the original inter-view reference picture. Moreover, the color compensation factors can be derived in both encoder and decoder, therefore no additional data need to be transmitted to the decoder. The experimental results show that the proposed method improves the coding efficiency of MVC and maintains good subjective quality.展开更多
In this paper,a new type of edge coloring of graphs together with an algorithm for such an edge coloring is presented to construct some columnweight three low-density parity-check(LDPC)codes whose Tanner graphs are fr...In this paper,a new type of edge coloring of graphs together with an algorithm for such an edge coloring is presented to construct some columnweight three low-density parity-check(LDPC)codes whose Tanner graphs are free of 4-cycles.This kind of edge coloring is applied on some well-known classes of graphs such as complete graphs and complete bipartite graphs to generate some column-weight 3 LDPC codes having flexibility in terms of code length and rate.Interestingly,the constructed(3;k)-regular codes with regularities k=4;5;:::;22 have lengths n=12;20;26,35;48;57;70;88;104;117;140;155;176;204;228;247;280;301;330;having minimum block length compared to the best known similar codes in the literature.In addition to linear complexity of generating such parity-check matrices,they can be considered as the base matrices of some quasi-cyclic(QC)LDPC codes with maximum achievable girth 18,which inherit the low-complexity encoder implementations of QC-LDPC codes.Simulation results show that the QC-LDPC codes with large girth lifted from the constructed base matrices have good performances and outperform random codes,progressive edge growth LDPC codes,some finite fields and group rings based QC-LDPC codes and also have a close competition to the standard IEEE 802.16e(WiMAX)code.展开更多
Color inconsistency between views is an important problem to be solved in multi-view video applications, such as free viewpoint television and other three-dimensional video systems. In this paper, by combining with mu...Color inconsistency between views is an important problem to be solved in multi-view video applications, such as free viewpoint television and other three-dimensional video systems. In this paper, by combining with multi-view video coding, a coding-oriented multi-view video color correction method is proposed. We first separate foreground and background in first Group Of Pictures （GOP） by using SKIP coding mode. Then by transferring means and standard deviations in backgrounds, color correction is performed for each frame in GOP, and multi-view video coding is performed and used to renew the backgrounds. Experimental results ances in color correction and multi-view video show the proposed method can obtain better performcoding.展开更多
In this paper,hyperbolic geometry is used to constructing new quantum color codes.We use hyperbolic tessellations and hyperbolic polygons to obtain them by pairing the edges on compact surfaces.These codes have minimu...In this paper,hyperbolic geometry is used to constructing new quantum color codes.We use hyperbolic tessellations and hyperbolic polygons to obtain them by pairing the edges on compact surfaces.These codes have minimum distance of at least 4 and the encoding rate near to 1,which are not mentioned in other literature.Finally,a comparison table with quantum codes recently proposed by the authors is provided.展开更多
A new 3D surface contouring and ranging system based on digital fringe projection and phase shifting technique is presented. Using the phase-shift technique, points cloud with high spatial resolution and limited accur...A new 3D surface contouring and ranging system based on digital fringe projection and phase shifting technique is presented. Using the phase-shift technique, points cloud with high spatial resolution and limited accuracy can be generated. Stereo-pair images obtained from two cameras can be used to compute 3D world coordinates of a point using traditional active triangulation approach, yet the camera calibration is crucial. Neural network is a well-known approach to approximate a nonlinear system without an explicit physical model, in this work it is used to train the stereo vision application system to calculating 3D world coordinates such that the camera calibration can be bypassed. The training set for neural network consists of a variety of stereo-pair images and the corresponding 3D world coordinates. The picture elements correspondence problem is solved by using projected color-coded fringes with different orientations. Color imbalance is completely eliminated by the new color-coded method. Once the high accuracy correspondence of 2D images with 3D points is acquired, high precision 3D points cloud can be recognized by the well trained net. The obvious advantage of this approach is that high spatial resolution can be obtained by the phase-shifting technique and high accuracy 3D object point coordinates are achieved by the well trained net which is independent of the camera model works for any type of camera. Some experiments verified the performance of the method.展开更多
Supplemental lighting has emerged as a widely adopted technique in greenhouse cultivation to enhance product visibility andimprove theflavor characteristics ofChinese bayberry(Myrica rubra)in the internationalmarket.W...Supplemental lighting has emerged as a widely adopted technique in greenhouse cultivation to enhance product visibility andimprove theflavor characteristics ofChinese bayberry(Myrica rubra)in the internationalmarket.While studies on lighting have predominantly focused on colorimetry,limited research has addressed the precise control of chromatic parameters and their effect on fruit quality.This study examined the effects of varying lighting conditions,specifically correlated color temperatures and illuminance,on the growth and quality of Chinese bayberry varieties“Black Charcoal”and“Dongkui”using a precision control system.The bayberry plants were exposed to a constant illuminance of 155μmol·m^(-2)·s^(-1) with chromatic levels ranging from 2250 to 6000 K.Black Charcoal demonstrated substantial improvements under different chromatic parameters,with fruit weight and size increasing by 40%and 14%,respectively.Furthermore,soluble solids content increased by 4% and vitamin C content rose by 142%,while organic acid content decreased by 30%.Dongkui,however,showed more modest responses under identical conditions,with fruit weight increasing by 2% and fruit size decreasing by 1%.Soluble solids and vitamin C contents showed minimal increases of 2% and 2.5%,respectively,while organic acid content decreased by 8%.The findings demonstrate that supplemental LED lighting significantly enhances both yield and quality parameters in Black Charcoal compared with Dongkui.These results provide valuable insights for optimizing Chinese bayberry cultivation,and the precise control methodology developed can be used to improve supplemental lighting strategies in other fruit and plant species.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.62375137 and 62175114).
文摘Structural colors based on metasurfaces have very promising applications in areas such as optical image encryption and color printing.Herein,we propose a deep learning-enabled reverse design of polarization-selective structural color based on coding metasurface.In this study,the long short-term memory(LSTM)neural network is presented to enable the forward and inverse mapping between coding metasurface structure and corresponding color.The results show that the method can achieve 98%accuracy for the forward prediction of color and 93%accuracy for the inverse design of the structure.Moreover,a cascaded architecture is adopted to train the inverse neural network model,which can solve the nonuniqueness problem of the polarization-selective color reverse design.This study provides a new path for the application and development of structural colors.
基金the National Key R&D Program of China(2021YFA1401200)Beijing Outstanding Young Scientist Program(BJJWZYJH01201910007022)+2 种基金National Natural Science Foundation of China(No.U21A20140,No.92050117)Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z211100004821009)X.Li acknowledges the support from Beijing Institute of Technology Research Fund Program for Young Scholars(XSQD-201904005).
文摘Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface holography can only realize static manipulation.In this study,we propose and demonstrate a multiplexing metasurface technique combined with multiwavelength code-division multiplexing(CDM)to realize dynamic manipulation.Multicolor code references are utilized to record information within a single metasurface and increase the information capacity and security for anticracks.A total of 48 monochrome images consisting of pure color characters and multilevel color video frames were reconstructed in dual polarization channels of the birefringent metasurface to exhibit high information density,and a video was displayed via sequential illumination of the corresponding code patterns to verify the ability of dynamic manipulation.Our approach demonstrates significant application potential in optical data storage,optical encryption,multiwavelengthversatile diffractive optical elements,and stimulated emission depletion microscopy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62001249 and 61871234)the NUPTSF(Grant No.NY220004)the Scientific Research Project of College of Information Engineering,Fuyang Normal University(Grant No.FXG2021ZZ02)。
文摘We propose a new full color ghost imaging scheme using both time and code division multiplexing technologies.In the scheme,the speckle patterns of three colors(red,green and blue)are modulated with different time slots and codes.The light intensity is sampled by one bucket detector.Then based on the modulated time slots and codes,we can effectively and simultaneously extract three detection component signals corresponding to three color components of objects from the sampling signal of the bucket detector.Finally,three component images resulting from the three component detection signals can be synthesized into a full color image.The experimental results verify the feasibility of our scheme under the limit of the number of time slots and codes.Moreover,our scheme reduces the number of bucket detectors and can realize high quality imaging even in a noisy environment.
基金Project supported by the National Natural Science Foundation of China (No. 60772134)the Innovation Foundation of Xidian University,China (No. Chuang 05018)
文摘A novel color compensation method for multi-view video coding (MVC) is proposed, which efficiently exploits the inter-view dependencies between views with the existence of color mismatch caused by the diversity of cameras. A color compensation model is developed in RGB channels and then extended to YCbCr channels for practical use. A modified inter-view reference picture is constructed based on the color compensation model, which is more similar to the coding picture than the original inter-view reference picture. Moreover, the color compensation factors can be derived in both encoder and decoder, therefore no additional data need to be transmitted to the decoder. The experimental results show that the proposed method improves the coding efficiency of MVC and maintains good subjective quality.
基金The authors would like to thank anonymous referees for their valuable comments enabled us to greatly improve the quality of the paper.The research of the first author is partially supported by Shahrekord University grant No.97GRN1M1465.
文摘In this paper,a new type of edge coloring of graphs together with an algorithm for such an edge coloring is presented to construct some columnweight three low-density parity-check(LDPC)codes whose Tanner graphs are free of 4-cycles.This kind of edge coloring is applied on some well-known classes of graphs such as complete graphs and complete bipartite graphs to generate some column-weight 3 LDPC codes having flexibility in terms of code length and rate.Interestingly,the constructed(3;k)-regular codes with regularities k=4;5;:::;22 have lengths n=12;20;26,35;48;57;70;88;104;117;140;155;176;204;228;247;280;301;330;having minimum block length compared to the best known similar codes in the literature.In addition to linear complexity of generating such parity-check matrices,they can be considered as the base matrices of some quasi-cyclic(QC)LDPC codes with maximum achievable girth 18,which inherit the low-complexity encoder implementations of QC-LDPC codes.Simulation results show that the QC-LDPC codes with large girth lifted from the constructed base matrices have good performances and outperform random codes,progressive edge growth LDPC codes,some finite fields and group rings based QC-LDPC codes and also have a close competition to the standard IEEE 802.16e(WiMAX)code.
基金the National Natural Science Foundation of China (No.60672073, No.60872094)the Program for New Century Excellent Talents in University (NCET-06-0537)+2 种基金the Key Project of Chinese Ministry of Education (No. 206059)Scientific Research Fund of Zhejiang Provincial Education Department (No.20070962)the Natural Science Foundation of Ningbo (No.2008A610016).
文摘Color inconsistency between views is an important problem to be solved in multi-view video applications, such as free viewpoint television and other three-dimensional video systems. In this paper, by combining with multi-view video coding, a coding-oriented multi-view video color correction method is proposed. We first separate foreground and background in first Group Of Pictures （GOP） by using SKIP coding mode. Then by transferring means and standard deviations in backgrounds, color correction is performed for each frame in GOP, and multi-view video coding is performed and used to renew the backgrounds. Experimental results ances in color correction and multi-view video show the proposed method can obtain better performcoding.
文摘In this paper,hyperbolic geometry is used to constructing new quantum color codes.We use hyperbolic tessellations and hyperbolic polygons to obtain them by pairing the edges on compact surfaces.These codes have minimum distance of at least 4 and the encoding rate near to 1,which are not mentioned in other literature.Finally,a comparison table with quantum codes recently proposed by the authors is provided.
基金Supported by the Eleventh Five-Year Pre-research Project of China.
文摘A new 3D surface contouring and ranging system based on digital fringe projection and phase shifting technique is presented. Using the phase-shift technique, points cloud with high spatial resolution and limited accuracy can be generated. Stereo-pair images obtained from two cameras can be used to compute 3D world coordinates of a point using traditional active triangulation approach, yet the camera calibration is crucial. Neural network is a well-known approach to approximate a nonlinear system without an explicit physical model, in this work it is used to train the stereo vision application system to calculating 3D world coordinates such that the camera calibration can be bypassed. The training set for neural network consists of a variety of stereo-pair images and the corresponding 3D world coordinates. The picture elements correspondence problem is solved by using projected color-coded fringes with different orientations. Color imbalance is completely eliminated by the new color-coded method. Once the high accuracy correspondence of 2D images with 3D points is acquired, high precision 3D points cloud can be recognized by the well trained net. The obvious advantage of this approach is that high spatial resolution can be obtained by the phase-shifting technique and high accuracy 3D object point coordinates are achieved by the well trained net which is independent of the camera model works for any type of camera. Some experiments verified the performance of the method.
基金funded by the Doctor Foundation of Southwest University of Science and Technology,grant number:24zx7116.
文摘Supplemental lighting has emerged as a widely adopted technique in greenhouse cultivation to enhance product visibility andimprove theflavor characteristics ofChinese bayberry(Myrica rubra)in the internationalmarket.While studies on lighting have predominantly focused on colorimetry,limited research has addressed the precise control of chromatic parameters and their effect on fruit quality.This study examined the effects of varying lighting conditions,specifically correlated color temperatures and illuminance,on the growth and quality of Chinese bayberry varieties“Black Charcoal”and“Dongkui”using a precision control system.The bayberry plants were exposed to a constant illuminance of 155μmol·m^(-2)·s^(-1) with chromatic levels ranging from 2250 to 6000 K.Black Charcoal demonstrated substantial improvements under different chromatic parameters,with fruit weight and size increasing by 40%and 14%,respectively.Furthermore,soluble solids content increased by 4% and vitamin C content rose by 142%,while organic acid content decreased by 30%.Dongkui,however,showed more modest responses under identical conditions,with fruit weight increasing by 2% and fruit size decreasing by 1%.Soluble solids and vitamin C contents showed minimal increases of 2% and 2.5%,respectively,while organic acid content decreased by 8%.The findings demonstrate that supplemental LED lighting significantly enhances both yield and quality parameters in Black Charcoal compared with Dongkui.These results provide valuable insights for optimizing Chinese bayberry cultivation,and the precise control methodology developed can be used to improve supplemental lighting strategies in other fruit and plant species.
