Modulation transfer function (MTF) is one of significant parameters for designing and evaluationg an photoelectric imaging system.As the traditional MTF measurement algorithm cannot meet the need of dynamic measurement for photoelectric system. A device composed of composed of three parts, including dynamic target generation unit, carrier motion simulation unit, data processing and control unit was setup. It is found that when the platform vibrates at low frequency, the decreasing speed of the dynamic transfer function of the television imaging system increases with the increase of the vibration frequency. When the platform vibrates at high frequency, the decreasing velocity of the dynamic transfer function of the television imaging system changes very weakly with the increase of the vibration frequency of the platform. When the platform vibrates at high frequency, the fluctuation of the decreasing velocity of the dynamic transfer function of the television imaging system decreases continuously with the increase of the vibration frequency, and gradually approaches 1 when the platform is at rest1.42 times.
Modulation transfer function (MTF) is one of significant parameters for designing and evaluating an photoelectric imaging system. As the traditional MTF measurement algorithm cannot meet the need of discrete sampling characteristics for photoelectric system, an automatic interpolaton and sub-pixel matching algorithm based on slit tilting method is proposed.Through the least-square analysis of line spread function (LSF),the tilting angle can be automatically calculated, and interpolaton of sub-pixel data can be precisely reconstructed. The noise of oscillation can be effectively restrained by a hanning window function. A device composed of target generator system, off-axis reflective collimator, mechanical adjustment, electrical control system, video acquisition module and comprehensive software was setup. The validity of the method was verified by experiments. The repeatability reached 0.007。
The image plane illumination nonuniformity caused by optical system or detector will affect the detection precision of photoelectric imaging system, especially in image guidance, positioning and recognition. An image plane illumination uniformity measurement device was set up, which was characteristiced of high uniformity and wide dynamic range. The device was composed of an asymmetric integrating sphere,the image collection and processing system, as well as the electrical control system.The asymmetric integrating sphere had two different radius,which was respectively 800mm and 1000mm.The spectral region was (0.4~1.1)μm, the illumination range was (1×10-4~2×104)lx. The image collection and processing system had two different acquisition card,which were respectively used for analog and digital signals. The software can process for dynamic image or static image. The TracePro software was used to make a internal ray tracing of integrating sphere, the illumination uniformity at the export was simulated for the size of 330mm×230mm and Φ 100mm export, the results were respectively 97.95% and 98.33%. Then,an illuminometer was used to measure the actual illumination uniformity of integrating sphere, the result was shown the actual illumination uniformity was 98.8%. Finally, a visible photoelectric imaging system was tested ,and three different uniformity indicators results were given.
The imaging plane’s illumination nonuniformity is an important parameter for wide FOV and short-focus optical imaging
system.But now the imaging plane’s illumination nonuniformity measurement device can not meet the requirements of
wide FOV, high uniformity and wide dynamic range.A new device combined with assymmetric double-hemisphere
technology was set up. It was composed of the special integrating sphere, CCD camera, precision displacement
mechanism, image acquisition, and testing software.The CCD was pre-calibrated and the testing software realized a
auto-correction,image acquisition, display and the illumination nonuniformity calulation.The light source was calibrated
by the national standard color temperature lamp.The device can provide a Lambert object surface .The advantages of the
device were that the FOV was as largely as 100°,and a wide illumination range of (10-3~103)Lx was achieved. An
optimal simulation of assymmetric double-hemisphere was calculated by LightTools,it was proved that the illuminace
nonuniformity at the outlet was better than 1.7%.Finally, the illumination nonuniformity of the integrating sphere and a
wide FOV and short-focus lens were respectively measured.The results show that, the illumination uniformity of the
integrating sphere is less than or equal to 1.49%,and the imaging plane’s illumination nonuniformity of the lens is
10.24%.
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