摘要
液晶检测设备在自动聚焦后由于焦距变化,成像分辨率也不可避免的发生变化,为此必须提供一种快速评估检测设备实际分辨率的方法。由于检测设备总分辨率为镜头分辨率与相机分辨率的乘积,因此论文提出先根据相机的各种噪声模型建立相机对比度分辨值,接着用频率渐变的LCD黑白样条光栅评估不同频率下镜头MTF的像质退化情况,最后通过分析分辨率与对比度关系,得出相机最高对比度下能够分辨出的经过成像系统像质退化产生亮暗模糊所对应的空间截止频率。实验表明在使用光学检测设备对手机背光源进行缺陷检测时,论文的方法评估实际分辨率>17μm,用背光源标定样品实际检测后可以得到,对于17μm以上缺陷检测设备都能清晰成像,因此结果证明了该方法的有效性。
Because of focus changing when TFT inspection device performing auto focus, the resolution of device will inevitably changes. So there is a need to offer a fast estimation method for device＇s actual resolution. Since total resolution is the product of camera resolution and lens resolution, at first, camera contrast limit is set up based on all kinds of noise model. Then, LCD white and black bar fringe are used whose frequency changes gradually to estimate lens MTF degeneration. Finally, through relationship between resolution and contrast, the spatial cut through frequency can be calculated by differentiating imaging system＇s light dark blur smallest differences at highest camera contrast distinguish condition. Experimental results indicates that when using optic inspection device to examine cell phone background light panel＇s defects, article＇s method estimates the actual resolution less than 17 μm, in contrast test, the calibrated sample defects exceeds 17μm can be photographed clearly using device. The results prove the effectiveness of the proposed method.
出处
《光电工程》
CAS
CSCD
北大核心
2012年第3期57-65,共9页
Opto-Electronic Engineering
基金
国家863高技术资助项目(2009AA04Z114)
