为了实现无遮拦、宽谱段、动态的局部高分辨成像, 设计了一种局部高分辨率的离轴主动反射变焦系统。该系统将离轴主动反射式变焦理论和局部动态高分辨率成像理论相结合, 实现了宽谱段范围内不同焦距处的动态局部高分辨成像。采用曲率半径可变的变形镜实现变焦, 避免了传统机械变焦中复杂的机械运动控制, 减轻了系统体积和重量并有效地保证了系统的宽谱段和大视场; 通过对变形镜面形的控制, 在不同焦距处实现了全视场内任意感兴趣区域的局部高分辨成像, 降低了数据传输量; 而采用无色差的反射式系统则克服了传统透射式及折反射式系统只能实现单色局部高分辨成像的缺点。经过优化设计,系统在可见光范围内成像, 焦距f′为75 mm(视场角FOV为x: 0°~0.5°, y: 3°~10°)~150 mm(FOV为x: 0°~0.5°, y: 1.7°~5°), F/#为7~14。理论和仿真分析表明, 系统在各焦距处感兴趣区域内的成像质量均可达到衍射极限, 实现了全视场内任意区域动态局部高分辨的成像效果。

To realize a broad spectrum and dynamic local high-resolution imaging, an off-axis reflective active zoom system is designed. This system combines off-axis reflective active zoom theory and local high-resolution theory together and realizes dynamic variable resolution in different focal lengths. Deformable mirrors(DMs) with variable curvature radii are used to change focal length to avoid complicated mechanical zoom movement control in a traditional system to reduce the volume and weight and to guarantee the broad spectrum of optical system. Through the control of deformable mirrors at different focal lengths, high-resolution within the Region of Interest(ROI) is achieved and the amount of data transmission is reduced. Moreover, as reflective systems have no chromatic aberration, it overcomes the disadvantages of monochrome imaging of traditional local high-resolution systems. After optimization, the imaging spectrum is visible light, the focal length ranges from 75 mm(Field of View(FOV) x: 0°—0.5°, y: 3°—10°)—150 mm(FOV x: 0°—0.5°, y: 1.7°—5°), the F/# is 7—14. The result of theoretical and simulation analysis indicates that the imaging quality of the ROI reaches the diffraction limit, and the system realizes dynamic local high-resolution in the FOV.