利用差分法配合灰度拉伸对颗粒运动图像进行了处理，直方图分析表明，像素在灰度上的分布特性与颗粒运动的剧烈程度具有相关性。差分图像中高亮度像素越多，颗粒运动越剧烈。随运动剧烈程度的降低，灰度相近的像素，其亮度由高向低变化。除去低亮度区域内自噪声的影响后，以对数函数为权值，在考虑了一定亮度范围内的像素分布后，提出了一个用于评价颗粒运动剧烈程度的指数。将其应用于流化床气泡生成图像序列表明，这种处理方法能够较好地评价颗粒的运动特点。

By using image difference and gray stretch technique, image histogram analysis method was used to investigate the movement of particles in image sequence. The result shows that the movement of particles has close relation with the dispersivity of pixels' greyvalue. The number of pixels with high brightness indicates the fierceness of particles. The brightness of pixels with similar grayscale will decrease with the slowdown of particles. After eliminating the influence of noise and taking consider of the gray level of pixels within certain range, a weight factor based on logarithm function was introduced to evaluate the intensity of particles' movement. Application of this algorithm in image sequence of fluidized bubble verifies the validity of this method.