The plenoptic camera is a single lens stereo camera which can retrieve the direction of light rays while detecting their intensity distribution. In this paper, to reveal more truths of plenoptic camera imaging, we pre...The plenoptic camera is a single lens stereo camera which can retrieve the direction of light rays while detecting their intensity distribution. In this paper, to reveal more truths of plenoptic camera imaging, we present the wavefront analysis for the plenoptic camera imaging from the angle of physical optics but not from the ray tracing model of geometric optics. Specifically, the wavefront imaging model of a plenoptic camera is analyzed and simulated by scalar diffraction theory and the depth estimation is redescribed based on physical optics. We simulate a set of raw plenoptic images of an object scene, thereby validating the analysis and derivations and the difference between the imaging analysis methods based on geometric optics and physical optics are also shown in simulations.展开更多
A numerical simulation model of plenoptic sensor aberration wavefront detection is established to simulate and analyze the detection performance of plenoptic sensor aberration wavefront for different turbulence intens...A numerical simulation model of plenoptic sensor aberration wavefront detection is established to simulate and analyze the detection performance of plenoptic sensor aberration wavefront for different turbulence intensities.The results show that the plenoptic sensor can achieve better distortion wavefront detection,and its wavefront detection accuracy improves with turbulence intensity.The unique optical structure design of the plenoptic sensor makes it more suitable for aberration wavefront detection in strong turbulent conditions.The wavefront detection performance of the plenoptic sensor is not only related to its wavefront reconstruction algorithm but also closely related to its structural parameter settings.The influence of structural parameters on the wavefront detection accuracy of plenoptic sensors under different turbulence intensities is simulated and analyzed.The variation law of wavefront detection accuracy and structural parameters under different turbulence intensities is summarized to provide a reference for the structural design and parameter optimization of plenoptic sensors.展开更多
The plenoptic imaging technique provides a promising approach to the non-invasive three-dimensional measurement, especially for the high-temperature combustion diagnosis. We establish a light-field convolution imaging...The plenoptic imaging technique provides a promising approach to the non-invasive three-dimensional measurement, especially for the high-temperature combustion diagnosis. We establish a light-field convolution imaging model for diffusion flame in this work, considering the radiation transfer process inside the diffusion flame and the light transfer process inside the focused plenoptic camera together. The radiation transfer process is described by the radiation transfer equation and solved by the generalized source multi-flux method. Wave optics theory is adopted to describe the light transfer process, combining Fresnel diffraction and the phase conversion of the lens. The flame light-field image is obtained by the light-field convolution imaging model and adopted as the measurement signal to reconstruct three-dimensional temperature field. The inverse problem of temperature reconstruction is solved by the least square QR decomposition method. The simulative temperature reconstruction work is conducted, including the inverse analysis, the uncertainty analysis, and the measurement noise influence. All the results show that the proposed measurement method is available to reconstruct three-dimensional temperature with satisfactory accuracy and acceptable uncertainty. Both symmetric and asymmetric distributed temperature fields are investigated, and the reconstructed results prove the validity and universality of the measurement method.展开更多
The ability of light gathering of plenoptic camera opens up new opportunities for a wide range of computer vision applications. An efficient and accurate method to calibrate plenoptic camera is crucial for its develop...The ability of light gathering of plenoptic camera opens up new opportunities for a wide range of computer vision applications. An efficient and accurate method to calibrate plenoptic camera is crucial for its development. This paper describes a 10-intrinsic-parameter model for focused plenoptic camera with misalignment. By exploiting the relationship between the raw image features and the depth–scale information in the scene, we propose to estimate the intrinsic parameters from raw images directly,with a parallel biplanar board which provides depth prior. The proposed method enables an accurate decoding of light field on both angular and positional information, and guarantees a unique solution for the 10 intrinsic parameters in geometry. Experiments on both simulation and real scene data validate the performance of the proposed calibration method.展开更多
Plenoptic imaging(PI)systems can flexibly record both spatial and angular information on flame radiation,enabling volumetric reconstruction of complex flames.The accuracy and efficiency of the reconstruction are signi...Plenoptic imaging(PI)systems can flexibly record both spatial and angular information on flame radiation,enabling volumetric reconstruction of complex flames.The accuracy and efficiency of the reconstruction are significantly affected by the orientation parameters of the microlens array(MLA)in the system.To investigate the influence of potential parameter errors on flame light fields,we establish a typical orientation error model and employ ray-splitting-based Monte Carlo method to simulate the entire and sectioned PI for the three-dimensional flame under four error conditions,in which different radiative properties of flame(extinction coefficient,scattering albedo,and scattering phase function)are considered.Through the proposed uncertainty evaluation scheme,the flame image characteristics,intensity,structure deviations,and their local distribution for four error types are analyzed.The results show that the extinction coefficient and the MLA error type determine the flame PI uncertainty features,while the scattering properties only change the deviation levels.The major impact of the extinction coefficient on the transfer and accumulation of uncertainty in flame-sectioned PI is also revealed.展开更多
All endoscopic imaging system using a plenoptic technique to reconstruct 3-D information is demonstrated and analyzed in this Letter. The proposed setup integrates a clinical surgical endoscope with a plenoptic camera...All endoscopic imaging system using a plenoptic technique to reconstruct 3-D information is demonstrated and analyzed in this Letter. The proposed setup integrates a clinical surgical endoscope with a plenoptic camera to achieve a depth accuracy error of about 1 mm and a precision error of about 2 mm, within a 25 mm×25 mm field of view, operating at 11 frames per second.展开更多
Light field imaging is an emerging technology in computational photography areas. Based on innovative designs of the imaging model and the optical path, light field cameras not only record the spatial intensity of thr...Light field imaging is an emerging technology in computational photography areas. Based on innovative designs of the imaging model and the optical path, light field cameras not only record the spatial intensity of three- dimensional （3D） objects, but also capture the angular information of the physical world, which provides new ways to address various problems in computer vision, such as 3D reconstruction, saliency detection, and object recognition. In this paper, three key aspects of light field cameras, i.e., model, calibration, and reconstruction, are reviewed extensively. Furthermore, light field based applications on informatics, physics, medicine, and biology are exhibited. Finally, open issues in light field imaging and long-term application prospects in other natural sciences are discussed.展开更多
Standard plenoptic camera can be used to capture multi-dimensional radiation information of high temperature luminous flame to reconstruct the temperature distribution. In this study, a novel method for reconstructing...Standard plenoptic camera can be used to capture multi-dimensional radiation information of high temperature luminous flame to reconstruct the temperature distribution. In this study, a novel method for reconstructing three-dimensional temperature field is proposed. This method is based on the optical tomography combined with standard plenoptic camera. The flame projection information from different planes is contained in one radiation image. In this model, we introduced the effective concept of the nearest neighbor method in the frequency domain to strip the interference of redundant information in the projection and to realize three-dimensional deconvolution. The flame emission intensity received by the pixels on the charge-coupled device sensor can be obtained according to the optical tomographic model. The temperature distributions of the axisymmetric and nonaxisymmetric flames can be reconstructed by solving the mathematical model with the nearest neighbor method. The numerical results show that three-dimensional temperature fields of high temperature luminous flames can be retrieved, proving the validity of the proposed method.展开更多
Light field rendering is an image-based rendering method that does not use 3 D models but only images of the scene as input to render new views.Light field approximation,represented as a set of images,suffers from so-...Light field rendering is an image-based rendering method that does not use 3 D models but only images of the scene as input to render new views.Light field approximation,represented as a set of images,suffers from so-called refocusing artifacts due to different depth values of the pixels in the scene.Without information about depths in the scene,proper focusing of the light field scene is limited to a single focusing distance.The correct focusing method is addressed in this work and a real-time solution is proposed for focusing of light field scenes,based on statistical analysis of the pixel values contributing to the final image.Unlike existing techniques,this method does not need precomputed or acquired depth information.Memory requirements and streaming bandwidth are reduced and real-time rendering is possible even for high resolution light field data,yielding visually satisfactory results.Experimental evaluation of the proposed method,implemented on a GPU,is presented in this paper.展开更多
基金supported by the Innovation Fund of Chinese Academy of Sciences(Grant No.CXJJ-6M208)
文摘The plenoptic camera is a single lens stereo camera which can retrieve the direction of light rays while detecting their intensity distribution. In this paper, to reveal more truths of plenoptic camera imaging, we present the wavefront analysis for the plenoptic camera imaging from the angle of physical optics but not from the ray tracing model of geometric optics. Specifically, the wavefront imaging model of a plenoptic camera is analyzed and simulated by scalar diffraction theory and the depth estimation is redescribed based on physical optics. We simulate a set of raw plenoptic images of an object scene, thereby validating the analysis and derivations and the difference between the imaging analysis methods based on geometric optics and physical optics are also shown in simulations.
基金the National Natural Science Foundation of China(No.61605223)the Strategic Priority Research Program of Chinese Academy of Sciences(No.614A010717)the Director Fund of Advanced Laser Technology Laboratory of Anhui Province(No.AHL2021ZR06)。
文摘A numerical simulation model of plenoptic sensor aberration wavefront detection is established to simulate and analyze the detection performance of plenoptic sensor aberration wavefront for different turbulence intensities.The results show that the plenoptic sensor can achieve better distortion wavefront detection,and its wavefront detection accuracy improves with turbulence intensity.The unique optical structure design of the plenoptic sensor makes it more suitable for aberration wavefront detection in strong turbulent conditions.The wavefront detection performance of the plenoptic sensor is not only related to its wavefront reconstruction algorithm but also closely related to its structural parameter settings.The influence of structural parameters on the wavefront detection accuracy of plenoptic sensors under different turbulence intensities is simulated and analyzed.The variation law of wavefront detection accuracy and structural parameters under different turbulence intensities is summarized to provide a reference for the structural design and parameter optimization of plenoptic sensors.
基金supported by the National Natural Science Foundation of China(Grant No.51976044)the National Science and Technology Major Project(Grant No.2017-V-0016-0069)the Foundation for Heilongjiang Touyan Innovation Team Program。
文摘The plenoptic imaging technique provides a promising approach to the non-invasive three-dimensional measurement, especially for the high-temperature combustion diagnosis. We establish a light-field convolution imaging model for diffusion flame in this work, considering the radiation transfer process inside the diffusion flame and the light transfer process inside the focused plenoptic camera together. The radiation transfer process is described by the radiation transfer equation and solved by the generalized source multi-flux method. Wave optics theory is adopted to describe the light transfer process, combining Fresnel diffraction and the phase conversion of the lens. The flame light-field image is obtained by the light-field convolution imaging model and adopted as the measurement signal to reconstruct three-dimensional temperature field. The inverse problem of temperature reconstruction is solved by the least square QR decomposition method. The simulative temperature reconstruction work is conducted, including the inverse analysis, the uncertainty analysis, and the measurement noise influence. All the results show that the proposed measurement method is available to reconstruct three-dimensional temperature with satisfactory accuracy and acceptable uncertainty. Both symmetric and asymmetric distributed temperature fields are investigated, and the reconstructed results prove the validity and universality of the measurement method.
基金supported by the National Natural Science Foundation of China (Nos. 61272287 and 61531014)the research grant of State Key Laboratory of Virtual Reality Technology and Systems (No. BUAAVR-15KF-10)
文摘The ability of light gathering of plenoptic camera opens up new opportunities for a wide range of computer vision applications. An efficient and accurate method to calibrate plenoptic camera is crucial for its development. This paper describes a 10-intrinsic-parameter model for focused plenoptic camera with misalignment. By exploiting the relationship between the raw image features and the depth–scale information in the scene, we propose to estimate the intrinsic parameters from raw images directly,with a parallel biplanar board which provides depth prior. The proposed method enables an accurate decoding of light field on both angular and positional information, and guarantees a unique solution for the 10 intrinsic parameters in geometry. Experiments on both simulation and real scene data validate the performance of the proposed calibration method.
基金supported by the National Natural Science Foundation of China(Grant No.51776051)。
文摘Plenoptic imaging(PI)systems can flexibly record both spatial and angular information on flame radiation,enabling volumetric reconstruction of complex flames.The accuracy and efficiency of the reconstruction are significantly affected by the orientation parameters of the microlens array(MLA)in the system.To investigate the influence of potential parameter errors on flame light fields,we establish a typical orientation error model and employ ray-splitting-based Monte Carlo method to simulate the entire and sectioned PI for the three-dimensional flame under four error conditions,in which different radiative properties of flame(extinction coefficient,scattering albedo,and scattering phase function)are considered.Through the proposed uncertainty evaluation scheme,the flame image characteristics,intensity,structure deviations,and their local distribution for four error types are analyzed.The results show that the extinction coefficient and the MLA error type determine the flame PI uncertainty features,while the scattering properties only change the deviation levels.The major impact of the extinction coefficient on the transfer and accumulation of uncertainty in flame-sectioned PI is also revealed.
基金supported by the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under Grant no.1R01EB020610
文摘All endoscopic imaging system using a plenoptic technique to reconstruct 3-D information is demonstrated and analyzed in this Letter. The proposed setup integrates a clinical surgical endoscope with a plenoptic camera to achieve a depth accuracy error of about 1 mm and a precision error of about 2 mm, within a 25 mm×25 mm field of view, operating at 11 frames per second.
基金Project supported by the National Natural Science Foundation of China （Nos. 61531014 and 61272287）
文摘Light field imaging is an emerging technology in computational photography areas. Based on innovative designs of the imaging model and the optical path, light field cameras not only record the spatial intensity of three- dimensional （3D） objects, but also capture the angular information of the physical world, which provides new ways to address various problems in computer vision, such as 3D reconstruction, saliency detection, and object recognition. In this paper, three key aspects of light field cameras, i.e., model, calibration, and reconstruction, are reviewed extensively. Furthermore, light field based applications on informatics, physics, medicine, and biology are exhibited. Finally, open issues in light field imaging and long-term application prospects in other natural sciences are discussed.
基金supported by the National Natural Science Foundation of China (Grant No. 51976044)the National Science and Technology Major Project (Grant No. 2017-V-0016-0069)the Foundation of Heilongjiang Touyan Innovation Team Program。
文摘Standard plenoptic camera can be used to capture multi-dimensional radiation information of high temperature luminous flame to reconstruct the temperature distribution. In this study, a novel method for reconstructing three-dimensional temperature field is proposed. This method is based on the optical tomography combined with standard plenoptic camera. The flame projection information from different planes is contained in one radiation image. In this model, we introduced the effective concept of the nearest neighbor method in the frequency domain to strip the interference of redundant information in the projection and to realize three-dimensional deconvolution. The flame emission intensity received by the pixels on the charge-coupled device sensor can be obtained according to the optical tomographic model. The temperature distributions of the axisymmetric and nonaxisymmetric flames can be reconstructed by solving the mathematical model with the nearest neighbor method. The numerical results show that three-dimensional temperature fields of high temperature luminous flames can be retrieved, proving the validity of the proposed method.
基金supported by The Ministry of Education,Youth and Sports from the National Programme of Sustainability(NPU II)project IT4Innovations excellence in science,LQ1602。
文摘Light field rendering is an image-based rendering method that does not use 3 D models but only images of the scene as input to render new views.Light field approximation,represented as a set of images,suffers from so-called refocusing artifacts due to different depth values of the pixels in the scene.Without information about depths in the scene,proper focusing of the light field scene is limited to a single focusing distance.The correct focusing method is addressed in this work and a real-time solution is proposed for focusing of light field scenes,based on statistical analysis of the pixel values contributing to the final image.Unlike existing techniques,this method does not need precomputed or acquired depth information.Memory requirements and streaming bandwidth are reduced and real-time rendering is possible even for high resolution light field data,yielding visually satisfactory results.Experimental evaluation of the proposed method,implemented on a GPU,is presented in this paper.
