Study on plate dot area detection based on digital image processing

This paper proposes a method of detecting dot area on the offset printing plate. The method uses an ordinary microscope photographic apparatus to get digital image by shooting the dot region on the plate. Then binarization processing the image by Threshold Segmentation Technology, noise processing the image that caused by shooting conditions by dilation and erosion operations, cutting the incomplete dot that are located on the image edge, we obtain a more precise dot area measurements that can be used to test the making quality of offset printing plate. The proposed method compensates the lack of precision instruments by image processing technology, reduces hardware requirements and use-cost to detect dot area in the print production process.