光电图像光照不均蜕化的校正及阈值分割方法*

分析了CCD获取的图像光照不均蜕化产生原因.针对光照不均蜕化的印刷电路板图像的具体情况,用同态滤波器在频域空间进行滤波而增强图像,从而改善图像的目标与背景对比度.讨论了最大类间方差法,给出了其优点.为了更好的分割图像,在此基础上,考虑两类间距与各类内聚性对图像分割的不同影响,提出了一种改进的最大类间方差法.最后对光照不均蜕化的PCB光电图像用不同方法进行了实验,结果表明改进方法能更好地分割图像.

Method for Nonuniform Illumination Ecdysis Emendation and Thresholding Segmentation in PCB Photoelectricity Image

The procreant reason of nonuniform illumination ecdysis in the received image through CCD is analyzed.Aiming at the frondose case of nonuniform illumination ecdysis PCB photoelectricity image,homostasis filter is used to enhance nonuniform illuminative image in the airspace in order to improve the contrast of the image between target and background.The method of maximum variance between clusters (Otsu) is discussed,and it′s advantage is given also.In order to segmentate image better,on the basis of the method of Otsu,and different influence of image segmentation about the factors of space between target and background as well as each kind of cohesion,an improved method of Otsu is proposed.The experiment is carried out by using different methods in the nonuniform illumination ecdysis PCB image,and the results of the experiment verifies that the PCB image can be segmentated better by using the improved method.