Patent ID: 8406501

Claim:
An appearance inspection method of a core of a heat exchanger provided with fins and tubes, comprising: a step of having an image device capture an image of the core of the heat exchanger and inputting into an image processing device the image data for storage, the image processing device performing: a step of identifying a region in the image data in which an image of a single tube of the heat exchanger core is captured, a step of performing averaging and dynamic binarization of the image data in this region to identify and extract only the image of the tube, a step of finding the smallest rectangle surrounding a tube for the image of the tube extracted so as to find a width dimension and length dimension of the tube, a step of comparing the tube width dimension and length dimension with a predetermined width threshold value and a predetermined length threshold value, respectively, to judge tube quality, a step of finding, with respect to the extracted tube image, a center axis in the longitudinal direction of the tube formed from center coordinates of the width direction of the tube, and a step of comparing the found center axis with a reference value to find a maximum displacement of the center axis across the longitudinal direction of the tube and judging the tube is defective when the maximum displacement is a predetermined threshold or more.