一种成像式亮度计校正方法北大核心CSCD

采用图像传感器的成像式亮度计可通过短焦距成像物镜实现大视场和空间分辨的亮度测量,但仍存在图像传感器像素非线性响应,短焦物镜产生的强烈渐晕效应及图像边缘畸变等问题。因此提出了一种成像式亮度计校正方法,利用标准辐射源法进行线性校正与平场校正,以获得线性修正系数和平场校正矩阵,通过几何坐标标定法获得畸变校正矩阵。采用焦距为12 mm的物镜及200万pixel的图像传感器搭建了成像式亮度计,经校正后完成了液晶显示屏发光亮度测量,与商用分光辐射亮度计进行了对比测试,测量相对误差不超过±2%,实现了大视场高精度空间分辨亮度测量。

Correction method of imaging luminance measurement device

The imaging luminance measurement device (ILMD) can utilize the image sensor and the short focal length lens to achieve a large field of view and spatially resolved luminance measurement. However, there still exists problems of pixel nonlinear response of image sensor, strong vignetting effects of short focal length lens and image distortion. Therefore, a correction method of ILMD was proposed. Linear correction and flat-field correction were used to obtain linear correction coefficients and flat-field correction matrices by using standard radiation source method. The distortion correction matrix was obtained through the geometric coordinates calibration method. A 12 mm short focal length lens and a 2-megapixel image sensor were adopted to build an ILMD. After correction, the luminance measurement of the LCD panel was completed. It was compared with a commercial spectroradiometer and the test results show that the relative error of measurement does not exceed ±2%, which realizes the large field of view, high-precision and spatially resolved luminance measurement.