Abstract: An image recognition system recognizes correspondence between object images contained respectively in two images obtained by two infrared ray cameras. One of the two images is set to a reference image and another of the two images to a comparison image. A correlation parameter indicative of a correlation between a reference pattern contained in the reference image and containing an object image and each pattern contained in the comparison image and identical in shape to the reference pattern is calculated by using a luminance value indicative of a luminance of the reference pattern and a luminance value indicative of a luminance of the each pattern contained in the comparison image. Based on the calculated correlation parameter, a pattern having a highest correlation with the reference pattern is extracted from the comparison image as a corresponding pattern which corresponds to the reference pattern.