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Modulation transfer function (MTF) measurement is a major means to evaluate the imaging quality of a space camera. The influence caused by the spectral characteristic of light source on the MTF results is not negligible, because the transmittance and color aberration of optical systems, and quantum efficiency of the space camera detectors are all spectrally related. Thus, MTF results tested by different light sources are different from each other. To address this problem, we propose a method to analyze the influence of spectral characteristics of light sources on measuring the MTF of space cameras. In addition, the devices and methods are designed to calibrate the spectral response and monochrome point spread function (PSF) of space camera. A Sigma lens (focal length: 1000mm, F number: 5.6) and a Cannon EOS 5DSR camera (pixel size: 4.14 μm) are combined into an experimental space camera, whose spectral response is calibrated with a monochromator (Omno30300, NBeT) and a spectral radiometer (FieldSpec, ASD). We calibrate the monochrome PSF of the Sigma lens with the same monochromator and a CCD (PIXIS 1024, Princeton Instruments, pixel size: 13 μm) micro-measuring system (20X objective). During the calibration of spectral response and monochrome PSF, the same collimator (focus: 5000 mm, F number: 10) is used. With using the proposed method and those calibrating data, we compute the theoretical values of the MTF of a space camera measured separately with five different light sources. The results indicate that MTF measured by a xenon lamp is greatly different from those MTFs measured by the other four light sources. Comparisons of those theoretically calculated MTFs, separately, show that the MTF measured by a tungsten halogen lamp is greater than the MTF measured by a xenon lamp at each spatial frequency. The deviation between those two lamps reaches a maximum value of 0.075 in the medium-high frequency zone. Furthermore, in order to verify those theoretical conclusions, a platform including a collimator and the previous space camera is constructed. The MTFs measured by a tungsten halogen lamp and a xenon lamp are computed with the slanted-edge method respectively. The results demonstrate that the distributions and deviations of the MTFs tested by those two lamps are identical to those theoretical results at each spatial frequency, with the maximum deviation being 0.057. The theoretical and experimental results demonstrate that the suggested method can accurately calculate the influence of spectral characteristics of light sources on measuring MTF of space cameras. The proposed method can also be adopted to investigate the influence of spectral characteristics of light sources on MTF of optical systems in the design or test stages.
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Keywords:
- optical test /
- modulation transfer function /
- space camera /
- spectral characteristic of light sources
[1] 吕乃光 2011 傅里叶光学(第2版)(北京: 机械工业出版社) 第50−52页
Lü N G 2011 Fourier Optics (2nd Ed.) (Beijing: China Machine Press) pp50−52 (in Chinese)
[2] Xie X F, Fan H D, Wang A D, Zou N Y, Zhang Y C 2018 Appl. Opt. 57 6552
Google Scholar
[3] Kenichiro M 2019 Opt. Express 27 1345
Google Scholar
[4] Jeffrey T O, Richard L E, Eddie L J 2007 Opt. Eng. 46 16403
Google Scholar
[5] Zhou Z X, Gao F, Zhao H J, Zhang L X, Ren L Q, Li Z, Muhammad U G, Liu H 2014 Opt. Express 22 2244
Google Scholar
[6] Fang Y C, Tsay H L, Huang G Y 2014 Appl. Opt. 53 195
Google Scholar
[7] ISO Standard 15529 2015 Optics and Photonics-Optical Transfer Function-Principles of Measurement of Modulation Transfer Function (MTF) of Sampled Imaging Systems
[8] Glenn D B, Sidney Y 1995 Appl. Opt. 34 8050
Google Scholar
[9] David N S, James S G, Regina K F 1995 Appl. Opt. 34 746
Google Scholar
[10] 吕恒毅, 薛旭成, 赵运隆, 韩诚山 2015 光学精密工程 23 1484
Google Scholar
Lü H Y, Xue X C, Zhao Y L, Han C S 2015 Opt. Prec. Eng. 23 1484
Google Scholar
[11] 段亚轩, 刘尚阔, 陈永权, 薛勋, 赵建科, 高立民 2017 物理学报 66 351
Google Scholar
Duan Y X, Liu S K, Chen Y Q, Xue X, Zhao J K, Gao L M 2017 Acta Phys. Sin. 66 351
Google Scholar
[12] Peter D B 2000 Proc. IS&T PICS Conf Portland, USA, January 1, 2000 p135
[13] ISO Standard 12233 2017 Photography-Electronic Still Picture Imaging-Resolution and Spatial Frequency Responses
[14] Don W, Peter D B 2014 IS&T/SPIE Electronic Imaging San Francisco, USA, February 3, 2014 p901605
[15] 周川杰, 吕政欣, 产晓冰, 李显斌 2011 航天返回与遥感 32 33
Google Scholar
Zhou C J, Lü Z X, Chan X B, Li X B 2011 Spacecraft Recov. Remot. Sens. 32 33
Google Scholar
[16] Alexis P T, Jonathan M M 1995 Opt. Eng. 34 1808
Google Scholar
[17] Li T C, Feng H J 2009 Sixth International Symposium on Multispectral Image Processing and Pattern Recognition Yichang, China, October 30, 2009 p74981
[18] Li T C, Feng H J Xu Z H 2011 Chin. Opt. Lett. 9 031101
Google Scholar
[19] 袁航飞, 郭永飞, 司国良, 李云飞, 曲立新 2015 光学学报 35 172
Google Scholar
Yuan H F, Guo Y F, Si G L, Li Y F, Qu L X 2015 Acta Opt. Sin. 35 172
Google Scholar
[20] Duan Y X, Xu S B, Yuan S C, Chen Y Q, Li H G, Da Z S, Gao L M 2018 Opt. Eng. 57 14103
Google Scholar
[21] Xie X F, Fan H D, Wang H Y, Wang Z B, Zou N Y 2018 Appl. Opt. 57 B83
Google Scholar
[22] Kenichiro M, Yamashita T, Nishida Y, Sugawara M 2014 Opt. Express 22 6040
Google Scholar
[23] GB/T 30697 2014 星载大视场多光谱相机性能测试方法
GB/T 30697 2014 Test Methods of Characteristics for Spaceborne Multispectral Camera with Wide Field of View (in Chinese)
[24] 李坤, 陈永权, 赵建科, 段亚轩, 李巧玲, 潘亮, 龙江波, 张海洋 2015 光学精密工程 23 2482
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Li K, Chen Y Q, Zhao J K, Duan Y X, Li Q L, Pan L, Long J B, Zhang H Y 2015 Opt. Prec. Eng. 23 2482
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[25] Battula T, Georgiev T, Gille J, Sergio G 2018 J. Electron. Imaging 27 13015
Google Scholar
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图 1 空间相机MTF检测系统组成
Figure 1. Configuration of a space camera MTF measurement system.
图 2 空间相机MTF检测系统光谱响应率标定原理图
Figure 2. Schematic of calibrating the spectral response of the space camera MTF measurement system.
图 3 空间相机光学系统单色PSF标定原理图
Figure 3. Schematic of calibrating the monochrome PSF of the optical system of a space camera.
图 4 空间相机MTF检测系统光谱响应标定结果
Figure 4. Calibration results of the spectral response of the space camera MTF measurement system.
图 5 常用光源光谱特性
Figure 5. Spectral characteristics of typical light sources.
图 6 空间相机光学系统多个波长处的单色PSF (a) 450 nm; (b) 500 nm; (c) 550 nm; (d) 600 nm; (e) 650 nm; (f) 700 nm
Figure 6. Monochrome PSF of the optical system of a space camera at: (a) 450 nm; (b) 500 nm; (c) 550 nm; (d) 600 nm; (e) 650 nm; (f) 700 nm.
图 7 单色光弥散斑直径随波长变化曲线图
Figure 7. Diameter of monochrome spot diagrams verse wavelength.
图 8 不同光源对应空间相机MTF理论值
Figure 8. Theoretical values of the space camera MTF corresponding to different light sources.
图 9 实验采集的刀口靶图像
Figure 9. Knife-edge image captured in the experiment.
图 10 卤钨灯和氙灯光源MTF检测结果
Figure 10. MTF measurement results with a tungsten halogen lamp and a xenon lamp.
表 1 卤钨灯和氙灯所得MTF理论值及其偏差
Table 1. Theoretical values and its deviation between the MTF measured with a tungsten halogen lamp and a xenon lamp.
光源 不同空间频率处的MTF ${f_c}/4$ ${f_c}/2$ $3{f_c}/4$ ${f_c}$ 卤钨灯 0.784 0.377 0.153 0.124 氙灯 0.750 0.302 0.091 0.089 卤钨灯与氙灯
间MTF偏差0.033 0.075 0.062 0.036 
DownLoad: CSV
表 2 卤钨灯和氙灯光源所得MTF检测结果及其偏差
Table 2. Test results and its deviation between the MTF measured with slanted-edge method by using a tungsten halogen lamp and a xenon lamp.
光源 不同空间频率处的MTF ${f_c}/4$ ${f_c}/2$ $3{f_c}/4$ ${f_c}$ 卤钨灯 0.460 0.248 0.091 0.053 氙灯 0.428 0.191 0.058 0.020 卤钨灯与氙灯
间MTF偏差0.032 0.057 0.033 0.033
DownLoad: CSV
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[1] 吕乃光 2011 傅里叶光学(第2版)(北京: 机械工业出版社) 第50−52页
Lü N G 2011 Fourier Optics (2nd Ed.) (Beijing: China Machine Press) pp50−52 (in Chinese)
[2] Xie X F, Fan H D, Wang A D, Zou N Y, Zhang Y C 2018 Appl. Opt. 57 6552
Google Scholar
[3] Kenichiro M 2019 Opt. Express 27 1345
Google Scholar
[4] Jeffrey T O, Richard L E, Eddie L J 2007 Opt. Eng. 46 16403
Google Scholar
[5] Zhou Z X, Gao F, Zhao H J, Zhang L X, Ren L Q, Li Z, Muhammad U G, Liu H 2014 Opt. Express 22 2244
Google Scholar
[6] Fang Y C, Tsay H L, Huang G Y 2014 Appl. Opt. 53 195
Google Scholar
[7] ISO Standard 15529 2015 Optics and Photonics-Optical Transfer Function-Principles of Measurement of Modulation Transfer Function (MTF) of Sampled Imaging Systems
[8] Glenn D B, Sidney Y 1995 Appl. Opt. 34 8050
Google Scholar
[9] David N S, James S G, Regina K F 1995 Appl. Opt. 34 746
Google Scholar
[10] 吕恒毅, 薛旭成, 赵运隆, 韩诚山 2015 光学精密工程 23 1484
Google Scholar
Lü H Y, Xue X C, Zhao Y L, Han C S 2015 Opt. Prec. Eng. 23 1484
Google Scholar
[11] 段亚轩, 刘尚阔, 陈永权, 薛勋, 赵建科, 高立民 2017 物理学报 66 351
Google Scholar
Duan Y X, Liu S K, Chen Y Q, Xue X, Zhao J K, Gao L M 2017 Acta Phys. Sin. 66 351
Google Scholar
[12] Peter D B 2000 Proc. IS&T PICS Conf Portland, USA, January 1, 2000 p135
[13] ISO Standard 12233 2017 Photography-Electronic Still Picture Imaging-Resolution and Spatial Frequency Responses
[14] Don W, Peter D B 2014 IS&T/SPIE Electronic Imaging San Francisco, USA, February 3, 2014 p901605
[15] 周川杰, 吕政欣, 产晓冰, 李显斌 2011 航天返回与遥感 32 33
Google Scholar
Zhou C J, Lü Z X, Chan X B, Li X B 2011 Spacecraft Recov. Remot. Sens. 32 33
Google Scholar
[16] Alexis P T, Jonathan M M 1995 Opt. Eng. 34 1808
Google Scholar
[17] Li T C, Feng H J 2009 Sixth International Symposium on Multispectral Image Processing and Pattern Recognition Yichang, China, October 30, 2009 p74981
[18] Li T C, Feng H J Xu Z H 2011 Chin. Opt. Lett. 9 031101
Google Scholar
[19] 袁航飞, 郭永飞, 司国良, 李云飞, 曲立新 2015 光学学报 35 172
Google Scholar
Yuan H F, Guo Y F, Si G L, Li Y F, Qu L X 2015 Acta Opt. Sin. 35 172
Google Scholar
[20] Duan Y X, Xu S B, Yuan S C, Chen Y Q, Li H G, Da Z S, Gao L M 2018 Opt. Eng. 57 14103
Google Scholar
[21] Xie X F, Fan H D, Wang H Y, Wang Z B, Zou N Y 2018 Appl. Opt. 57 B83
Google Scholar
[22] Kenichiro M, Yamashita T, Nishida Y, Sugawara M 2014 Opt. Express 22 6040
Google Scholar
[23] GB/T 30697 2014 星载大视场多光谱相机性能测试方法
GB/T 30697 2014 Test Methods of Characteristics for Spaceborne Multispectral Camera with Wide Field of View (in Chinese)
[24] 李坤, 陈永权, 赵建科, 段亚轩, 李巧玲, 潘亮, 龙江波, 张海洋 2015 光学精密工程 23 2482
Google Scholar
Li K, Chen Y Q, Zhao J K, Duan Y X, Li Q L, Pan L, Long J B, Zhang H Y 2015 Opt. Prec. Eng. 23 2482
Google Scholar
[25] Battula T, Georgiev T, Gille J, Sergio G 2018 J. Electron. Imaging 27 13015
Google Scholar
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