Method of extracting pixels constituting intensity changes in an image and method of identifying collection of intensity changes

摘要

A method for extracting pixels constituting an intensity change formed of a collection of local intensity changes present in a gray image of an object based on a intensity data of each pixel includes the steps of: photographing the object by an image photographing device to obtain the gray image of the object represented by the intensity data of pixels; setting a partial image with a predetermined shape and a predetermined size in the image which has a target pixel whose entire periphery is surrounded by adjacent pixels; calculating intensity data belonging to a specific area composed of the target pixel and peripheral pixels and intensity data belonging to its remaining area for the partial image; obtaining a ratio of the calculating results between the intensity data belonging to the specific area and the intensity data of the remaining area, and comparing the obtained ratio with a threshold value, and then determining suitability of the target pixel as a composing factor of the intensity change based on a compared result, and then extracting pixels constituting the intensity change which have been determined to be suitable.