可见光/红外双视场全景式航空侦查相机光学系统设计

Optical system design of visible/infrared and double-FOV panoramic aerial camera

为提高航空侦查识别目标能力以及满足部队全天候作战需要,设计了一种应用于全景航空侦查相机的可见光/红外双视场成像光学系统。可见光光学系统焦距为165mm/660mm,相对孔径为1:8.8,视场角为9.1°×6.8°/2.3°×1.7°;红外光学系统焦距为75mm/300mm,相对孔径为1:4,视场角为8.3°×6.2°/2.1°×1.6°。采用有限焦距光学系统前面加一个望远系统的方法实现变倍,根据红外器件及可见光器件的像元尺寸计算出红外系统及可见光系统的奈奎斯特频率分别为33lp/mm和91lp/mm。在33lp/mm处,红外光学系统大、小视场的MTF值分别为为0.35和0.37,在91lp/mm处,可见光光学系统大、小视场MTF值分别为0.41和0.4,成像质量接近衍射极限,表明光学系统成像质量良好,满足实际工程使用要求。

Visible/infrared double-FOV optical system used for panoramic aerial camera is de- signed in this paper, aiming at improving target survelliance and recoganizing capability and meeting requirements of combat demand of troops around the clock. Focal length, relative aperture and field angle of visible optical system is 165 Mm/660 mm, 1： 8.8, and 9.1°×6.8°/ 2.3°× 1.7° respectively, while focal length, relative aperture and viewing angle of infrared optical system is 75 ram/300 mm, 1：4, and 8.3°× 6.2°/2. 1°× 1.6° respectively. Zooming is realized by adding telescopic system in front of the limited focal length optical system. According to pixel size of infrared device and visible light device, Nyquist frequency of infrared system and visible light system are calculated as 33 lp/mm and 91 lp/mm respectively. At 33 lp/mm, infrared optical system with large and small field of view of the MTF values are 0.35 and 0.37 while at 91 lp/mm, visible light optical system with large and small field MTF are 0.41 and 0.4. Image quality is close to diffraction limit, which shows image quality of optical system can satisfies needs of practical engineering.