The radial distortion of projector magnetic lenses with field distributions in the form of inverse law has been theoretically studied using analytical method. The radial distortion coefficient can be expressed explici...The radial distortion of projector magnetic lenses with field distributions in the form of inverse law has been theoretically studied using analytical method. The radial distortion coefficient can be expressed explicitly in term of Bessel function of fraction order Therefore, analytical formulae for radial distortion coefficient of each projector magnetic lenses in this article have derived to computation these coefficients. Also, the dimensionless quality factors for radial distortion are calculated to estimate the performance of image in electron microscope. The results of calculations show that the increasing of order of multipole （n） leads to increase the radial distortion coefficient.展开更多
Tabletop integral imaging display with a more realistic and immersive experience has always been a hot spot in three-dimensional imaging technology,widely used in biomedical imaging and visualization to enhance medica...Tabletop integral imaging display with a more realistic and immersive experience has always been a hot spot in three-dimensional imaging technology,widely used in biomedical imaging and visualization to enhance medical diagnosis.However,the traditional structural characteristics of integral imaging display inevitably introduce the flipping effect outside the effective viewing angle.Here,a full-parallax tabletop integral imaging display without the flipping effect based on space-multiplexed voxel screen and compound lens array is demonstrated,and two holographic functional screens with different parameters are optically designed and fabricated.To eliminate the flipping effect in the reconstruction process,the space-multiplexed voxel screen consisting of a projector array and the holographic functional screen is presented to constrain light beams passing through the corresponding lens.To greatly promote imaging quality within the viewing area,the aspherical structure of the compound lens is optimized to balance the aberrations.It cooperates with the holographic functional screen to modulate the light field spatial distribution.Compared with the simulation results,the distortion rate of the imaging display is reduced to less than 9%from more than 30%.In the experiment,the floating high-quality reconstructed three-dimensional image without the flipping effect can be observed with the correct 3D perception at 96°×96°viewing angle,where 44,100 viewpoints are employed.展开更多
The acquisition of images with a fish-eye lens can cause serious image distortion because of the short focal length of the lens.As a result,it is difficult to use the obtained image information.To make use of the effe...The acquisition of images with a fish-eye lens can cause serious image distortion because of the short focal length of the lens.As a result,it is difficult to use the obtained image information.To make use of the effective information in the image,these distorted imagesmust first be corrected into the perspective of projection images in accordance with the human eye’s observation abilities.To solve this problem,this study presents an adaptive classification fitting method for fish-eye image correction.The degree of distortion in the image is represented by the difference value of the distances fromthe distorted point and undistorted point to the center of the image.The target points selected in the image are classified by the difference value.In the areas classified by different distortion differences,different parameter curves were used for fitting and correction.The algorithm was verified through experiments.The results showed that this method has a substantial correction effect on fish-eye images taken by different fish-eye lenses.展开更多
文摘The radial distortion of projector magnetic lenses with field distributions in the form of inverse law has been theoretically studied using analytical method. The radial distortion coefficient can be expressed explicitly in term of Bessel function of fraction order Therefore, analytical formulae for radial distortion coefficient of each projector magnetic lenses in this article have derived to computation these coefficients. Also, the dimensionless quality factors for radial distortion are calculated to estimate the performance of image in electron microscope. The results of calculations show that the increasing of order of multipole （n） leads to increase the radial distortion coefficient.
基金The Basic Research Fund of Central-Level Nonprofit Scientific Research Institutes(No.TKS20220304)The Key Research and Development Projects of Guangxi Science and Technology Department(No.2021AB05087).
文摘Tabletop integral imaging display with a more realistic and immersive experience has always been a hot spot in three-dimensional imaging technology,widely used in biomedical imaging and visualization to enhance medical diagnosis.However,the traditional structural characteristics of integral imaging display inevitably introduce the flipping effect outside the effective viewing angle.Here,a full-parallax tabletop integral imaging display without the flipping effect based on space-multiplexed voxel screen and compound lens array is demonstrated,and two holographic functional screens with different parameters are optically designed and fabricated.To eliminate the flipping effect in the reconstruction process,the space-multiplexed voxel screen consisting of a projector array and the holographic functional screen is presented to constrain light beams passing through the corresponding lens.To greatly promote imaging quality within the viewing area,the aspherical structure of the compound lens is optimized to balance the aberrations.It cooperates with the holographic functional screen to modulate the light field spatial distribution.Compared with the simulation results,the distortion rate of the imaging display is reduced to less than 9%from more than 30%.In the experiment,the floating high-quality reconstructed three-dimensional image without the flipping effect can be observed with the correct 3D perception at 96°×96°viewing angle,where 44,100 viewpoints are employed.
基金supported by the National Natural Science Foundation of China(Grant No.51775390)the Open Research Fund Program of Hubei Provincial Key Laboratory of Chemical Equipment Intensification and Intrinsic Safety(Grant Nos.2016KA02 and 2018KA01).
文摘The acquisition of images with a fish-eye lens can cause serious image distortion because of the short focal length of the lens.As a result,it is difficult to use the obtained image information.To make use of the effective information in the image,these distorted imagesmust first be corrected into the perspective of projection images in accordance with the human eye’s observation abilities.To solve this problem,this study presents an adaptive classification fitting method for fish-eye image correction.The degree of distortion in the image is represented by the difference value of the distances fromthe distorted point and undistorted point to the center of the image.The target points selected in the image are classified by the difference value.In the areas classified by different distortion differences,different parameter curves were used for fitting and correction.The algorithm was verified through experiments.The results showed that this method has a substantial correction effect on fish-eye images taken by different fish-eye lenses.
