Nippon Telegraph & Telephone Corp. N.t.t. Fanet Systems Corp.

Masakatsu Nunotani

Akira Shindo

Katsuyuki Tanimizu

The present invention provides an image matching method which allows non-ear image positional shifts to be corrected on a real time basis, and an economical product testing system using this method. A two dimensional test image, consisting of pixels arranged as a matrix of bits distributed in both the vertical direction and the horizontal scanning direction, and an associated reference image are subjected to template matching at a cell matching arithmetic unit for each of line blocks consisting of a plurality of scan lines. The result of the template matching are quantitatively evaluated at an evaluation unit as being good or bad, and positional shifts are sequentially computed according to good evaluation results. Based on the positional shifts thus obtained, the comparative pixel addresses are accordingly corrected before the two images are compared at the comparator.

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Machida, Japan

Masakatsu Nunotani