Abstract: For the deficiency of the length measurement technology of large vehicles limited by actually application environment, this paper proposes an image-based metrology solution for the length measurement of large vehicles. We use the image segment method to extract different portions of the same vehicle from multiple images, and the matching method based on image edge feature to stitch the segmented parts into a complete profile of the vehicle. We assume that the side of vehicle is an approximate plane. We map the image coordinates onto a reference plane on which the distances between any two points can be measured in physical dimension. With the knowledge of the depths of the reference plane and vehicle side, we can map measurements on the reference plane onto the side of the vehicles using linear transformations. We tested the method with many vehicles of different types, and got pleasing results without environmental restriction.
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Key words: vehicle length measurement, machine vision, image stitching