Terahertz (THz) waves have great potential applications in communication, imaging, and spectroscopy fields. Effective THz modulators are highly desired to realize those functionalities. Wherein, as a kind of artificial composite material, THz metamaterials can achieve extraordinary responses to the electromagnetic wave through the geometric structure design. Nevertheless, normal metamaterials have no tunability once they have been designed and fabricated. To overcome this issue, active medias have been explored to enable the expected modulation of metamaterials under the external stimuli. Among them, phase transition materials are often used in dynamically tunable THz devices due to their intriguing properties. Particularly, vanadium dioxide (VO2) has attracted attention owing to the reversible physical properties and can exhibit insulator-to-metal transition (IMT) behavior at near room temperature. Here, we explore the strength of the resonance response and the change of spectral lineshape caused by the size variation in the metamaterial unit cell. On this basis, adding VO2 thin film can realize broadband modulation during the IMT process. Furthermore, by incorporating the VO2 patches in the gold microstructure can further achieve the dual modulation of amplitude and frequency simultaneously. The design of VO2 hybrid metamaterial can break the single function limitation of traditional metamaterial modulators, reduce material loss, and open up a new path for the development of multifunctional THz modulators.
{"title":"Dual-modulation terahertz device based on amplitude and frequency in VO2 hybrid metamaterial","authors":"Longyu Shi, Huiwen Shi, Xuteng Zhang, Wanlin Liang, Suqi Zhang, Huijuan Sun, Qing-li Zhou, Cunlin Zhang","doi":"10.1117/12.2683141","DOIUrl":"https://doi.org/10.1117/12.2683141","url":null,"abstract":"Terahertz (THz) waves have great potential applications in communication, imaging, and spectroscopy fields. Effective THz modulators are highly desired to realize those functionalities. Wherein, as a kind of artificial composite material, THz metamaterials can achieve extraordinary responses to the electromagnetic wave through the geometric structure design. Nevertheless, normal metamaterials have no tunability once they have been designed and fabricated. To overcome this issue, active medias have been explored to enable the expected modulation of metamaterials under the external stimuli. Among them, phase transition materials are often used in dynamically tunable THz devices due to their intriguing properties. Particularly, vanadium dioxide (VO2) has attracted attention owing to the reversible physical properties and can exhibit insulator-to-metal transition (IMT) behavior at near room temperature. Here, we explore the strength of the resonance response and the change of spectral lineshape caused by the size variation in the metamaterial unit cell. On this basis, adding VO2 thin film can realize broadband modulation during the IMT process. Furthermore, by incorporating the VO2 patches in the gold microstructure can further achieve the dual modulation of amplitude and frequency simultaneously. The design of VO2 hybrid metamaterial can break the single function limitation of traditional metamaterial modulators, reduce material loss, and open up a new path for the development of multifunctional THz modulators.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121073946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rong Ye, Xiangwu Gao, Tingting Zeng, Xianyun Wu, Hongmei Li, Renxuan Liu
A novel spectrum reshaping approach of scanning amplitude limiting based on Optical Kerr effect is proposed to overcome the undesirable spectral gain narrowing and blueshift effect in chirped pulse amplification (CPA). The theoretical analysis of the scheme is demonstrated and the reshaping performance of F-P interference filtering device with built-in Optical Kerr medium are simulated and discussed. For the initial Gaussian spectrum of chirped pulse with ns magnitude of 800nm central wavelength and 20nm bandwidth, the "saddle shape" and "blue shift" spectrum are obtained by the proposed spectrum reshaping approach. The theoretical analysis and numerical simulation show that the spectrum of chirped laser pulses can be reshaped flexibly by the proposed scanning amplitude limiting method based on Optical Kerr effect. Furthermore, it is necessary to reduce the deviation of pump intensity as much as possible so as to match the reshaped spectrum with the desired spectrum.
{"title":"Spectrum reshaping of chirped laser pulse by scanning amplitude limiting based on optical Kerr effect","authors":"Rong Ye, Xiangwu Gao, Tingting Zeng, Xianyun Wu, Hongmei Li, Renxuan Liu","doi":"10.1117/12.2682965","DOIUrl":"https://doi.org/10.1117/12.2682965","url":null,"abstract":"A novel spectrum reshaping approach of scanning amplitude limiting based on Optical Kerr effect is proposed to overcome the undesirable spectral gain narrowing and blueshift effect in chirped pulse amplification (CPA). The theoretical analysis of the scheme is demonstrated and the reshaping performance of F-P interference filtering device with built-in Optical Kerr medium are simulated and discussed. For the initial Gaussian spectrum of chirped pulse with ns magnitude of 800nm central wavelength and 20nm bandwidth, the \"saddle shape\" and \"blue shift\" spectrum are obtained by the proposed spectrum reshaping approach. The theoretical analysis and numerical simulation show that the spectrum of chirped laser pulses can be reshaped flexibly by the proposed scanning amplitude limiting method based on Optical Kerr effect. Furthermore, it is necessary to reduce the deviation of pump intensity as much as possible so as to match the reshaped spectrum with the desired spectrum.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131238999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phase technology is widely utilized in the field of optics. By applying phase technology, the required pattern can be obtained by remodeling the light field in the focal area of the objective lens, which has significant value in laser manufacturing, biomedicine and optical imaging. Gerchberg-Saxton algorithm is commonly used in imaging systems to restructure the light field, which is achieved by converting light intensity distribution of the Fourier plane optical field into the phase distribution on the focal plane through the inverse Fourier transform. Nevertheless, for a high numerical aperture objective lens, the accuracy of the relationship between the phase and the intensity of the light field may be compromised by depolarization effects, which causes the Fourier transform unable to accurately generate the required lattice pattern from the known light intensity distribution. To obtain the intensity of the light field and phase information during the optical transmission process from the rear focal plane to the front focal plane of the objective lens, we utilize the Debye diffraction in place of the Fourier transform in the Gerchberg-Saxton algorithm. Image skeletonization is a morphology-based image processing technology used to extract the backbone structure and shape information in the image, which extracts the main structure of the image and generates a more simplified representation by eliminating redundant information in the image. Image skeletonization technology has applications in many fields, including computer vision and medical image processing, among others. In this paper, we demonstrated the generation of lattice patterns from arbitrary images in the strong focusing of light field using Debye diffraction theory and image skeletonization technology.
{"title":"Generation of arbitrary lattice pattern in the strong focusing of light field via image skeletonization and Debye diffraction","authors":"Hao Wu, Zhipeng Zhang, Qianxiang Wan, Hongyu Zhang, Zihao Li, Haoran Chen, Xianlin Song","doi":"10.1117/12.2685439","DOIUrl":"https://doi.org/10.1117/12.2685439","url":null,"abstract":"Phase technology is widely utilized in the field of optics. By applying phase technology, the required pattern can be obtained by remodeling the light field in the focal area of the objective lens, which has significant value in laser manufacturing, biomedicine and optical imaging. Gerchberg-Saxton algorithm is commonly used in imaging systems to restructure the light field, which is achieved by converting light intensity distribution of the Fourier plane optical field into the phase distribution on the focal plane through the inverse Fourier transform. Nevertheless, for a high numerical aperture objective lens, the accuracy of the relationship between the phase and the intensity of the light field may be compromised by depolarization effects, which causes the Fourier transform unable to accurately generate the required lattice pattern from the known light intensity distribution. To obtain the intensity of the light field and phase information during the optical transmission process from the rear focal plane to the front focal plane of the objective lens, we utilize the Debye diffraction in place of the Fourier transform in the Gerchberg-Saxton algorithm. Image skeletonization is a morphology-based image processing technology used to extract the backbone structure and shape information in the image, which extracts the main structure of the image and generates a more simplified representation by eliminating redundant information in the image. Image skeletonization technology has applications in many fields, including computer vision and medical image processing, among others. In this paper, we demonstrated the generation of lattice patterns from arbitrary images in the strong focusing of light field using Debye diffraction theory and image skeletonization technology.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"12711 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131345840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Visible light communication (VLC) has attracted attention due to its promising future. However, the low bandwidth of the light source leads to the relatively low communication rate. In this work, a measurement platform mainly consisted of signal source and oscilloscope is established to measure the 3-dB modulation bandwidth of LED. Experiments are conducted to investigate the influences of the LED’s working current, distribution of LED array, and LED’s driving circuit on the working bandwidth of the VLC system. When the LED driving current increases from 22 mA to 32 mA, the corresponding 3-Db bandwidth of the blue LED is improved from 1.8 MHz to 2.3 MHz. Designing blue LED array with the controlled internal distance between the neighboring LEDs aimed at improving the overall working bandwidth of the commercial light sources. The 3-Db bandwidth of a single blue LED is 1.8 M under the working current of 20 mA. The 3- dB bandwidth of the 2×2 blue LED array in series is 2.9 M under the working current of 20 mA with the optimized internal distance of 10 mm. Under the same measurement conditions, the 3-Db bandwidth of 1×2 blue LEDs in parallel is improved from 1.8 M to 2.9 M after adding the as-designed LED driving circuit.
{"title":"An investigation on the application solution of light emitting diodes for improving the working bandwidth in visible light communication","authors":"Li Jiang, Junxuan Tu, Guoyang Cao, Shaolong Wu","doi":"10.1117/12.2683917","DOIUrl":"https://doi.org/10.1117/12.2683917","url":null,"abstract":"Visible light communication (VLC) has attracted attention due to its promising future. However, the low bandwidth of the light source leads to the relatively low communication rate. In this work, a measurement platform mainly consisted of signal source and oscilloscope is established to measure the 3-dB modulation bandwidth of LED. Experiments are conducted to investigate the influences of the LED’s working current, distribution of LED array, and LED’s driving circuit on the working bandwidth of the VLC system. When the LED driving current increases from 22 mA to 32 mA, the corresponding 3-Db bandwidth of the blue LED is improved from 1.8 MHz to 2.3 MHz. Designing blue LED array with the controlled internal distance between the neighboring LEDs aimed at improving the overall working bandwidth of the commercial light sources. The 3-Db bandwidth of a single blue LED is 1.8 M under the working current of 20 mA. The 3- dB bandwidth of the 2×2 blue LED array in series is 2.9 M under the working current of 20 mA with the optimized internal distance of 10 mm. Under the same measurement conditions, the 3-Db bandwidth of 1×2 blue LEDs in parallel is improved from 1.8 M to 2.9 M after adding the as-designed LED driving circuit.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124750787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Spintronic terahertz emitters (STEs) with the feature of high performance and low cost have been a hot spot in the field of terahertz sources. However, little attention has been paid to the control and modulation of the THz waves generated by the STE. In this paper, we propose a unidirectional spintronic terahertz emitter (USTE) integrated a common STE with a metal grating. The dyadic Green’s function method and finite element method are adopted to survey the characteristics of the USTE. Simulation results show that the metal grating has a transmission larger than 97% in the optical band. Meanwhile it also has a higher reflectivity larger than 99% in the THz band. As a result, the USTE has a unidirectional THz emission along the direction of the pump beam with a larger than 4-fold enhancement in intensity. Besides, the USTE has the capability of tuning the central frequency. We think that this USTE can be used in THz wireless communications and holographic imaging, especially in the field of THz bio-sensing, which needs some resonance frequencies to sense.
{"title":"Spintronic terahertz emitters with unidirectional radiation","authors":"Xiaoqiang Zhang, Yunqing Jiang, Yong Xu, Fengguagn Liu, Weisheng Zhao","doi":"10.1117/12.2683875","DOIUrl":"https://doi.org/10.1117/12.2683875","url":null,"abstract":"Spintronic terahertz emitters (STEs) with the feature of high performance and low cost have been a hot spot in the field of terahertz sources. However, little attention has been paid to the control and modulation of the THz waves generated by the STE. In this paper, we propose a unidirectional spintronic terahertz emitter (USTE) integrated a common STE with a metal grating. The dyadic Green’s function method and finite element method are adopted to survey the characteristics of the USTE. Simulation results show that the metal grating has a transmission larger than 97% in the optical band. Meanwhile it also has a higher reflectivity larger than 99% in the THz band. As a result, the USTE has a unidirectional THz emission along the direction of the pump beam with a larger than 4-fold enhancement in intensity. Besides, the USTE has the capability of tuning the central frequency. We think that this USTE can be used in THz wireless communications and holographic imaging, especially in the field of THz bio-sensing, which needs some resonance frequencies to sense.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127747122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The tunability of optical transmittance spectra can be available by mounting one of the mirrors of the Fabry-Perrot cavity on a movable structure. The F-P filter prepared by adopting MEMS process can realize the advantages of miniaturization, array, and high output. The size of the MEMS F-P filter can be reduced to a few hundred micrometers. This feature introduces a new problem for the characterization of optical performance, that is, the incident light needs to be focused onto the mirror with a size of a few hundred micrometers. However, in the actual test, the incident light with a hundred-micron spot is usually a convergent beam with a certain cone angle. It is found that through theoretical analysis, compared to parallel incident light, the convergent light beam passed through the F-P cavity leads to the decrease at peak transmittance and the broadening of full width at half maximum. The reason for that was the converging light with a cone angle passing through the F-P cavity had different incident angles and caused diverse optical path difference. As a result, the light emitting from the cavity with various wavelength would appear in the transmission spectra. In summary, the test results under the converging light could not truly reflect the performance of the F-P cavity and the influence of the cone angle of incident light beam on the performance characterization of MEMS F-P filter was analyzed by theoretical arithmetic and simulation.
{"title":"Effect of the cone angle of incident light beam on the performance characterization of MEMS F-P filter","authors":"Meng Zhang, Chengao Yang, Weiping Wang, Jing Cao, Songyi Liu, Xiaoyan Hu","doi":"10.1117/12.2684221","DOIUrl":"https://doi.org/10.1117/12.2684221","url":null,"abstract":"The tunability of optical transmittance spectra can be available by mounting one of the mirrors of the Fabry-Perrot cavity on a movable structure. The F-P filter prepared by adopting MEMS process can realize the advantages of miniaturization, array, and high output. The size of the MEMS F-P filter can be reduced to a few hundred micrometers. This feature introduces a new problem for the characterization of optical performance, that is, the incident light needs to be focused onto the mirror with a size of a few hundred micrometers. However, in the actual test, the incident light with a hundred-micron spot is usually a convergent beam with a certain cone angle. It is found that through theoretical analysis, compared to parallel incident light, the convergent light beam passed through the F-P cavity leads to the decrease at peak transmittance and the broadening of full width at half maximum. The reason for that was the converging light with a cone angle passing through the F-P cavity had different incident angles and caused diverse optical path difference. As a result, the light emitting from the cavity with various wavelength would appear in the transmission spectra. In summary, the test results under the converging light could not truly reflect the performance of the F-P cavity and the influence of the cone angle of incident light beam on the performance characterization of MEMS F-P filter was analyzed by theoretical arithmetic and simulation.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122488773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiaqing Dong, Zilong Li, Xuan Liu, Wenhua Zhong, Guijun Wang, Qiegen Liu, Xianlin Song
In recent years, three-dimensional (3D) display technology has developed rapidly, and it is widely used in education, medical, military and other fields. 3D holographic display is regarded as the ultimate solution of 3D display. However, the lack of 3D content is one of the challenges that has been faced by 3D holographic display. The traditional method uses light-field camera and RGB-D camera to obtain 3D information of real scene, which has the problems of high-system complexity and long-time consumption. Here, we proposed a 3D scene acquisition and reconstruction system based on optical axial scanning. First an electrically tunable lens (ETL) was used for high-speed focus shift (up to 2.5 ms). A CCD camera was synchronized with the ETL to acquire multi-focused image sequence of real scene. Then, Tenengrad operator was used to obtain the focusing area of each multi-focused image, and the 3D image were obtained. Finally, the Computer-generated Hologram (CGH) can be obtained by the layer-based diffraction algorithm. The CGH was loaded onto the space light modulator to reconstruct the 3D holographic image. The experimental results verify the feasibility of the system. This method will expand the application of 3D holographic display in the field of education, advertising, entertainment, and other fields.
{"title":"A 3D scene acquisition and reconstruction system via optical axial scanning","authors":"Jiaqing Dong, Zilong Li, Xuan Liu, Wenhua Zhong, Guijun Wang, Qiegen Liu, Xianlin Song","doi":"10.1117/12.2685016","DOIUrl":"https://doi.org/10.1117/12.2685016","url":null,"abstract":"In recent years, three-dimensional (3D) display technology has developed rapidly, and it is widely used in education, medical, military and other fields. 3D holographic display is regarded as the ultimate solution of 3D display. However, the lack of 3D content is one of the challenges that has been faced by 3D holographic display. The traditional method uses light-field camera and RGB-D camera to obtain 3D information of real scene, which has the problems of high-system complexity and long-time consumption. Here, we proposed a 3D scene acquisition and reconstruction system based on optical axial scanning. First an electrically tunable lens (ETL) was used for high-speed focus shift (up to 2.5 ms). A CCD camera was synchronized with the ETL to acquire multi-focused image sequence of real scene. Then, Tenengrad operator was used to obtain the focusing area of each multi-focused image, and the 3D image were obtained. Finally, the Computer-generated Hologram (CGH) can be obtained by the layer-based diffraction algorithm. The CGH was loaded onto the space light modulator to reconstruct the 3D holographic image. The experimental results verify the feasibility of the system. This method will expand the application of 3D holographic display in the field of education, advertising, entertainment, and other fields.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128156583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Xing, J. Xiong, P. Zhao, Jiuchang Deng, Z. Cui, Fanchao Meng, Lingqiang Meng, J. Jia
A domestic space-borne transportable FP cavity is designed. The cavity length is 100 mm with the shape of a cube. Spacer is made of ultra-low expansion glass. This cavity is four-point mounting and heat insulated from external environmental fluctuation. To judge the performance of this cavity, an ultra-stable laser based on this cavity was constructed, the frequency noise of which is below 30Hz/√ Hz, which can fulfill the requirements of the Taiji-2 mission.
{"title":"Development of space-borne transportable high-finesse Fabry–Pérot cavity and its performance in ultra-stable laser","authors":"C. Xing, J. Xiong, P. Zhao, Jiuchang Deng, Z. Cui, Fanchao Meng, Lingqiang Meng, J. Jia","doi":"10.1117/12.2683956","DOIUrl":"https://doi.org/10.1117/12.2683956","url":null,"abstract":"A domestic space-borne transportable FP cavity is designed. The cavity length is 100 mm with the shape of a cube. Spacer is made of ultra-low expansion glass. This cavity is four-point mounting and heat insulated from external environmental fluctuation. To judge the performance of this cavity, an ultra-stable laser based on this cavity was constructed, the frequency noise of which is below 30Hz/√ Hz, which can fulfill the requirements of the Taiji-2 mission.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114993312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the traditional Fourier single-pixel imaging (FSPI), compressed sampling is often used to improve the acquisition speed. However, the reconstructed image after compressed sampling often has a lower resolution and the quality is difficult to meet the imaging requirements of practical applications. To address this issue, we proposed a novel imaging method that combines deep learning and single-pixel imaging, which can reconstruct high-resolution images with only a small-scale sampling. In the training phase of the network, we attempted to incorporate the physical process of FSPI into the training process. To achieve this objective, a large number of natural images were selected to simulate Fourier single-pixel compressed sampling and reconstruction. The compressed reconstructed samples were subsequently employed for network training. In the testing phase of the network, the compressed reconstruction samples of the test dataset were input into the network for optimization. The experimental results showed that compared with traditional compressed reconstruction methods, this method effectively improved the quality of reconstructed images.
{"title":"Fast high-resolution imaging combining deep learning and single-pixel imaging","authors":"X. Liu, Zilong Li, Jiaqing Dong, Guijun Wang, Wenhua Zhong, Qiegen Liu, Xianlin Song","doi":"10.1117/12.2684974","DOIUrl":"https://doi.org/10.1117/12.2684974","url":null,"abstract":"In the traditional Fourier single-pixel imaging (FSPI), compressed sampling is often used to improve the acquisition speed. However, the reconstructed image after compressed sampling often has a lower resolution and the quality is difficult to meet the imaging requirements of practical applications. To address this issue, we proposed a novel imaging method that combines deep learning and single-pixel imaging, which can reconstruct high-resolution images with only a small-scale sampling. In the training phase of the network, we attempted to incorporate the physical process of FSPI into the training process. To achieve this objective, a large number of natural images were selected to simulate Fourier single-pixel compressed sampling and reconstruction. The compressed reconstructed samples were subsequently employed for network training. In the testing phase of the network, the compressed reconstruction samples of the test dataset were input into the network for optimization. The experimental results showed that compared with traditional compressed reconstruction methods, this method effectively improved the quality of reconstructed images.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114321105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Color cameras are widely used in many fields such as printing industry, graphic arts, medical treatment, and environment. On the premise of saving cost, in order to ensure that the color rendering effect of the camera is as close as possible to the imaging of the human eye, a method of using color filters to correct the total spectral response curve of the color camera is proposed. The principle of correction is to make the total spectral response of the system meet the Luther condition. By adding such a filter, the adjusted camera sensitivity function can be very close to a certain linear transformation of the color matching function of the human visual system. Due to the manufacturing process, the transmittance of the produced filter can only be a smooth curve. Starting from the factors that affect the accuracy of the filter simulation, we express the transmittance of the filter as a certain smoothness in the calculation process combination of basis functions. Different basis functions will lead to different results. Here we use discrete cosine transform basis functions, polynomial basis functions, Fourier basis functions and radial basis functions to conduct experiments. Under the condition of each basis function, a corresponding optimal spectral transmittance curve will be obtained. Taking the 14 standard test colors recommended by the International Commission of Illumination as a reference, the CIE1976 color difference formula is used to calculate the theoretical color difference of the corrected camera under the condition of different basis functions. Finally, the performance of the basis function is evaluated from three indicators: Vora-Value, NRMSE and color difference.
{"title":"Camera filter design based on optimized basis functions","authors":"Chenyu Zhang","doi":"10.1117/12.2682999","DOIUrl":"https://doi.org/10.1117/12.2682999","url":null,"abstract":"Color cameras are widely used in many fields such as printing industry, graphic arts, medical treatment, and environment. On the premise of saving cost, in order to ensure that the color rendering effect of the camera is as close as possible to the imaging of the human eye, a method of using color filters to correct the total spectral response curve of the color camera is proposed. The principle of correction is to make the total spectral response of the system meet the Luther condition. By adding such a filter, the adjusted camera sensitivity function can be very close to a certain linear transformation of the color matching function of the human visual system. Due to the manufacturing process, the transmittance of the produced filter can only be a smooth curve. Starting from the factors that affect the accuracy of the filter simulation, we express the transmittance of the filter as a certain smoothness in the calculation process combination of basis functions. Different basis functions will lead to different results. Here we use discrete cosine transform basis functions, polynomial basis functions, Fourier basis functions and radial basis functions to conduct experiments. Under the condition of each basis function, a corresponding optimal spectral transmittance curve will be obtained. Taking the 14 standard test colors recommended by the International Commission of Illumination as a reference, the CIE1976 color difference formula is used to calculate the theoretical color difference of the corrected camera under the condition of different basis functions. Finally, the performance of the basis function is evaluated from three indicators: Vora-Value, NRMSE and color difference.","PeriodicalId":184319,"journal":{"name":"Optical Frontiers","volume":"399 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122995961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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