METHOD AND APPARATUS FOR PROCESSING IMAGE SIGNAL IN FLUORESCENT MAGNETIC POWDER FLAW DETECTION

摘要

PURPOSE:To enhance the S/N ratio to the background noise of an image signal, by using an adding signal, to which the intensities of the signals of a definite number of unit sections have been added, as the signal intensity of the image signal for signal processing. CONSTITUTION:An image signal processing circuit is constituted of image pickup devices 18, 20, an A/D converter 22, a memory 44, a microcomputer 46, etc. The image signals SS outputted from the image pickup devices 18, 20 picking up the image of the fluorescent magnetic powder pattern adhered to the surface flaw part of a material 10 to be tested and divided into unit sections less than the quantity corresponding to the scanning line thereof to calculate the signal intensities of the image signals at every unit section. Said unit sections are divided into a plurality of intermediate sections consisting of a definite number of mutually adjacent unit sections and signal intensities are added at every intermediate section to calculate the intensity of an adding signal. Then, adding signal intensities in a pair of mutually adjacent intermediate sections are compared and the larger one is set to the signal intensity in the large section consisting of a pair of the intermediate sections and signal processing is performed on the basis of said signal intensity.