Computation of a cross-section structure: a projection-based approach

While most of the existing depth recovery methods compute 21/2D depth information from 2-D intensity images, the method described in this paper recovers the cross-section of a scene by processing the line images of a line scan camera. This method has some advantages as compared to the existing stereo methods. Line images, which are combined to make a slit image, are taken by moving the line scan camera along a linear rail. The depth of a pixel is directly related to the slope of a straight line in the slit image. Thus one of the advantages is that correspondence becomes the problem of detecting straight lines in the slit image. Another advantage is that we can obtain very high resolution images if we use a line scan camera, since it is not difficult to find CCD sensors with 4 ii or more linear arrays in the market. Hough transforms are used to find straight lines in the slit image. Instead of the number of points on a line, each cell in Hough space records the intensity variation of the pixels on a line. We derive the mathematical background of this method and show some experimental results with several real images. This scheme has a important potential for industrial and scientific application capability with greater refinement. (C) 1998 Elsevier Science B.V. All rights reserved.