针对高动态范围目标，本文设计了一种基于数字微镜器件(DMD)，能够对高动态目标进行自动区域调光的望远系统，其中DMD为中间像面。首先DMD上所有微反射镜处于开状态，获取一幅目标景象的图像，按照平均灰度和局部动态将该图像划分为若干小区域，并设定各区域的曝光时间等参数。按照确定的参数逐区控制DMD微反射镜的开关状态及时间，并完成探测器的曝光成像，获得具有高动态范围的图像。设计的望远系统焦距为223 mm，F数为5，视场为3°，工作波段为480～760 nm，最终系统的动态范围可达140 dB。设计结果表明，在DMD像面上，各视场 MTF 在 Nyquist 频率处均大于0.70，畸变接近于0；在探测器像面上，各视场 MTF 在 Nyquist频率处均大于0.55，畸变小于2%。%To improve the dynamic range of imaging equipment when detecting targets with great intensity differences simultaneously, a pixel-level adjustable telescope based on Digital Micromirror Device (DMD) is designed. The system has an intermediate image plane on DMD. First of all, the micromirrors of the DMD are on and one image of the target is obtained and divided into several little zones according to mean gray level and locality dynamic,and parameters such as time of exposure of each zone are set up. It is effective based on the parameters to modulate the corresponding micromirror’s on-off statement and time, which will improve the dynamic range of the system. The dynamic range of the designed telescope with effective focal length of 223 mm, F-number of 5, field of 3° and wavelength range from 480 nm to 760 nm, can be up to 140 dB. The design results show that, on the image plane of DMD, the modulation transfer functions of each field is greater than 0.70 at Nyquist frequency and the distortion is close to 0, and on the image plane of detector, the modulation transfer function of each field is greater than 0.55 at Nyquist frequency and the distortion is less than 2%.
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