基于直方图凹度分析的印刷网点图二值化算法研究

摘要

在印刷工业上,为了用数字图像处理的方法测量印刷网点的参数,二值化是图像预处理过程中关键的一步,直接影响参数测量的精度.在分析已有数字图像二值化方法的基础上,结合印刷网点图的特征,提出一种基于直方图凹度分析的二值化方法.该算法根据印刷网点图像的灰度直方图特征,利用数学求导的思想求出灰度直方图中双峰之间的谷所对应的灰度值,将该值作为二值化的阈值.实验证明,该方法可以比较准确地求出印刷网点图的二值化阈值,和已有算法相比,扫描率低、速度快、计算准确,具有很好的应用前景.%In printing industry, if the printing dot parameters are measured by way of image processing, binarization is a key step of image pre-proceesing, which affects the measuring accuracy. After analyzing all binarization methods, and considering the features of the printing dot image, a new method based on histogram concavity analysis is proposed. It takes the gray value of the valley between the peaks of histogram as the threshold for the binarization. Experiments show that compared with other methods, this method can get the threshold of the print dot image with a higher speed and accuracy. As a result, it has a good application prospect.