Patent ID: 7313265

Claim:
A stereo calibration apparatus for obtaining a transformation matrix, which is an image transformation parameter between a pair of image pickup devices for photographing a preset common area, the stereo calibration apparatus comprising: an image input device to which a pair of images is input from the one pair of image pickup devices; a straight-line detector detecting at least four straight lines from each image of the pair of images output from the image input device; a straight-line correspondence detector detecting at least four sets of corresponding lines between the pair of images by using an image feature in a neighboring area of each of the four straight lines detected for each image of the pair of images; and a transformation matrix calculator calculating the transformation matrix by using the sets of corresponding lines, wherein the straight-line correspondence detector is configured to: obtain data series regarding the image feature in the neighboring area for each of the four straight lines detected for each image of the pair of images; obtain data differences between each of data in the data series of each of the four straight lines detected for a first image of the pair of images and each of data in the data series of each of the four straight lines detected for a second image of the pair of images; obtain normalized distances by normalizing a weighted sum of the data differences using a sum of weighting factors; and determine one of the four straight lines in the first image of the pair of images and the corresponding one of the four straight lines in the second image of the pair of images having a smallest normalized distance as a pair of corresponding lines.