一种图像处理的全自动焦度计

An Image Processing Auto Lensmeter

为了提高全自动焦度计的测量精度和适应性,提出了一种测量图形和计算方法。该研究方法是首先利用脉冲恒流驱动的红外光将16点图像经光学系统投射到面阵CCD上,然后经高速CPU系统采集处理,变成二值化图像,最后用最小二乘法计算出镜片的屈光参数。实验用标准镜片、划伤镜片和镜片落灰尘进行了测试,同四点测量图像进行了比较,实验结果表明标准镜片误差小于国家计量规定屈光度检查最小误差±0.06 D,且都符合国家计量标准,划伤镜片和镜片落灰尘时测量精度明显提高,环境适应性也大大提高。

A new image measurement and calculating method was proposed to improve the measurement accuracy and adaptability of auto lensmeter. Firstly, 16 dots infrared, image driven by constant pulse current was received with CCD. Secondly, image was processed by high speed CPU system, and binary image was divided up by CPU system. Finally, we can acquire the diopter parameter of glass by least square method. The experiment was carried out using the standard glass and the glass with nick and dirt. Compared with 4 dots method, results show that the measurement errors are less than ±0.06 D which was minimum error of diopter prescribed by National Metrology Bureau. In addition, the accuracy of the glass with nick and dirt was improved obviously, and adaptability of environment was also enhanced.