DETECTION OF PILLING

PURPOSE:To permit objective decision by detecting the shadows of the pilling generated by projecting light to a sample from diagonal above by an image pickup element and processing the detected image by setting a prescribed threshold. CONSTITUTION:A sample cloth 1 is set on a sample base 2 and the light is projected from a light source 3 to the sample cloth 1. The focus of a television camera 4 is blurred to the extent of prohibiting the discrimination of the pilling and the image screen in the out-of-focus state is sent to an image processing circuit 6 and is stored in a RAM 9. The camera is then focussed to the pilling on the cloth 1 while the stop is held the same and this image screen is sent to the circuit 6. The non-focussed image screen input is subtracted from the focussed image screen input by a CPU 10 and the difference thereof is compared with the threshold stored in a ROM 8 and is classified to bright or dark. The differences classified to dark, i.e., the differences discriminated as the shadows of the pilling are counted. This operation is repeated N-types and the average value of the N times is determined. Since the shadows of the pilling are mechanically processed and counted, the generation of the error based on the test operator's subjectivity is obviated.