激光打在漫反射屏上形成直径几厘米的近场光斑, 人工使用照度计能直接测量光斑照度, 但容易造成误差。本文通过数字摄像法得到相机拍摄的光斑图像的灰度, 在 Tsai模型基础上考虑漫反射率和相机离轴角的影响, 建立了光斑照度映射与图像灰度的数学模型, 由图像中的灰度能计算得到漫反射屏上光斑的照度。该方法简单、准确。通过实验和数据分析结果表明: 光斑上不同位置目标点的照度映射后和图像对应像元灰度的关系符合 CCD响应度的线性关系, 从而为研究漫反射屏上照度测量方法提供了新的参考。

laser forms a smaller diameter spot in the diffuse reflection screen. By using the light meter to measure the spot illumination, artificial multiple operations is likely to cause errors. This article uses digital photography, calculating the image intensity of the spot camera, establishing the spot illumination and gray of the mathematical mapping model and deriving the mathematical formula based on the Tsai model. The method is simple and accurate. Through experiments and data analysis, the experimental results show that illumination mapping of the location of points and the image corresponding to the gray spot on the CCD response linear relationship provide a new reference for the mapping of the diffuse reflection screen illumination and CCD image gray value.