IMAGE MEASURING INSTRUMENT

摘要

PROBLEM TO BE SOLVED: To improve the success probability of a correlative calculation method by discriminating the correspondence relation with use of a reference data block whose magnification has been changed and a search data block. SOLUTION: A single sheet of reference image is decided out of a set of stereoscopic images obtained by photographing a pattern projection object, and another sheet of image is used as a search image. A data setting part 22 sets a search area in the search image and then sets a search data block of lateral width L. A data magnification decision part 24 decides the local length L1 at a position near a search object point included in a reference image and then decides the local length L2 of the search data block. An arithmetic processing part 23 segments the data from the reference image in width of L'+(L1/L2)×L and changes the magnification (L2/L1) to obtain a reference data block. Then, an area correlative coefficient is calculated between the reference data block and the search data block.