| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for determining a 2D gradient magnitude image from a range image of an object. SOLUTION: The range image includes a plurality of intensity values corresponding to distances from an object surface at respective pixel locations. For each pixel, the values of a horizontal central difference (dx) and a vertical central distance (dy) are determined. A 2D gradient magnitude image value at each pixel is set to 0.5*sqrt(dx<2> +dy<2> +4). The range image is scaled so that a unit intensity value at each pixel corresponds to a unit distance value. The magnitude of a gradient at a 3D point p can be determined from the scaled range image and the gradient magnitude image. First, a perpendicular projection (x, y) of p onto the scaled range image is computed and a gradient magnitude at (x, y) is interpolated from the corresponding values of the 2D gradient magnitude image near the location (x, y). Finally, the magnitude of the gradient at p is set to the interpolated gradient magnitude at (x, y). |
