Evaluation of Pilling by Computer Image Analysis

The distribution curve of pill sizes, the total number and the total area of pills, and the mean area of pills are obtained from the image of a pilling smaple which is read into a computer with a TV camera. Then, how to determine the pilling grades of different samples by comparing their pilling feature values with those of the standard photographs in JIS L 1076 is discussed. The results obtained are as follows:1. The region of the small size in the distribution curve of pill sizes, which is obtained from the image of sample, contain the components owing to the reflection from woven yarns and naps. It is considered that the distribution for the pill sizes larger than threshold Ta is assumed to be correct.2. This threshold Ta; for the standard photographs is determined so that the total number of pills obtained by the image analysis may coincide with that obtained by the visual inspection of photograph. The values of Ta; are different with the groups of the standard photographs, but nearly constant for different grades in every group. The Ta; for the group whose distribution curve of pill size resembles that of a given sample can be used as Ta; for the given sample.3. The pilling grades of a given sample can be determined by comparing its total number or total area of pills with that for the standard photographs of different grades in the group a distribution curve of which resembles that of the sample. However, the judgment of pilling grade by the two dimensional expression of pilling feature value is better than that by the single feature value, that is, the total number or area of pills.