This paper reports the application of image analysis methods we developed previ ously to characterize fiber diameter distribution in nonwovens using a "distance trans form." The method is verified by a series of simulated nonwoven images as well as some real web images used previously, including a carded web, a relatively dense spunbonded fabric, and another relatively open area-bonded spunbonded. The results indicate that the distance transform can be used successfully to characterize fiber diameter.