6%以内。 The droplet size distribution is evaluated by image processing. The traces of the captured droplet on water-sensitive papers are detected by a camera and then sent for segment and evaluation by a specially developed program. An improved GLV algorithm is used to separate the conglutinated droplets and compute their size data comparing to the discrete droplets. Comparison experiments are conducted to measure the droplet size distribution by a laser particle size analyzer. The evaluation result shows that the error between the data set given by image process and the data set from laser analyzer is less than 6%.