Registration correction method in image processing, and vegetation state display method using the registration correction method

A registration correction method applicable to image processing for matching a visible ray image formed in a visible ray band area with an invisible ray image formed in an invisible ray band area,

• the method comprising the steps of:
• designating one of the visible ray image and the invisible ray image as a reference image, and the other as an object image;
• setting a plurality of reference points at different spots within the reference image;
• setting a reference window enclosing each of the reference points;
• determining differential values of brightness in the x-axis and y-axis directions of each pixel in each reference window;
• setting an object point in the object image and an object window enclosing the object point, the object window being of the same size as each reference window;
• determining differential values of brightness in the x-axis and y-axis directions of each pixel in the object window, while shifting the object window by the pixel within the object image;
• obtaining the total of the squares or the absolute values of the differences between the differential values of each corresponding pixels of the reference window and the object window;
• designating the object point where the total becomes smallest as the point corresponding to the reference point of each reference window;
• and
• matching the visible ray image with the invisible ray image, with a plurality of the designated points being reference points for the matching.