成像光路布置对数字相机热致测量误差影响规律的研究

On the Influence of Imaging Light Path Layout on Thermo-Induced Measurement Error of Digital Camera

研究了数字相机成像系统中物距和成像系统固定方式两个因素对相机自发热导致的图像变形误差的影响规律,通过分析得到了热致图像"虚变形"与物距的倒数关系并进行了实验检验。推导了固定位置位于镜头上时图像"虚变形"的表达式并进行了实验验证。研究表明,无论是成像系统的固定点位于相机上还是镜头上,自发热都会使得图像发生一个虚的膨胀变形,其大小与镜头接口的热膨胀参数和像距有关。本研究得到的模型和规律为指导实际光测力学应用中的光路布置以减小数字相机自发热导致的测量误差提供了理论依据。

In this paper, the influence of two important factors in digital camera imaging system, i.e. object distance and fixed form of imaging system, on measurement error due to image distortion induced by spontaneous heating is investigated. Through analysis, the reciprocal relationship between thermo-induced image virtual deformation and object distance was obtained and verified experimentally. When the fixed position is at the lens, the image virtual deformation expression was derived, and its validation was also varified by experiment. Experimental results show that no matter what the imaging system fixed position is on the camera or on the lens, the spontaneous heating will make the image a virtual expansion distortion, and its size is related to the thermal expansion parameter of lens mount interface and image distance. Above results may provide the theoretical evidence for reducing digital camera thermo-induce measurement error through imaging light path layout in photomechanics application.