JP2725567B

PURPOSE:To provide a image processing method for measuring an etch pit density by obtaining binarized images and counting the number of independent graphics while changing plural threshold values within a range where recognition exclusive of the etch pits is not possible with the magnified images of an etching surface. CONSTITUTION:The image processing to obtain the binarized images, to count the number of the independent graphics and to determine (c) to maximize the number of graphics as the threshold value while changing the threshold value to plural stages in the range of (b) to (e) where the etch pits 1, 2 of Fig. are recognized and the ruggedness of the etching surface of all the parts 3 exclusive of the etch pits is not recognized is executed at the time of measuring the etch pit density of the microscopically magnified images of the etching surface of a semiconductor single crystal by image processing. The optimum threshold value at which the number of graphics is maximized varies with every measurement point and is automatically determined. The number of the etch pits is thus exactly determined. Since this method is for automatic measurement, there is no need for operators and individual differences do not arise.