在分析研究数字图像描述方法的基础上,通过实验建立了定量金相中晶粒度等级与数字图像特征参数一阶概率分布的关系,确定了基于灰度的晶粒度等级的计算方法。结果表明,晶粒度等级和晶粒总面积与晶界总长度之比的对数成线性关系;晶粒度等级和细化后的晶粒组织图像的图像特征参数一阶概率p(255)、p(0)之比的对数成线性关系。基于灰度等级的晶粒度等级的计算方法简单、快捷。 Based on the analysis of the digital image description method, the relationship between the grained metallographic grade and the first-order probability distribution of the digital image was established experimentally, and the calculation method of grading based on grayscale was determined. The results show that the logarithm of the grain size grade and the total grain area to the total length of the grain boundaries is linear. The first order probability p (255) of the grain size grade and the image feature parameters of the refined grain image is ), P (0) ratio of the logarithm of a linear relationship. The method of calculating the graininess level based on the grayscale is simple and fast.