Off-Line Stereo Plotting by Means of Image Correlation

The algorithm of automatic stereo plotting by iterative image correlation from aerial photographs and the corresponding empirical tests are described. The algorithm is oriented to off-line process, using a image scanner and a general purpose computer, and consists of 3 hierarchical correlation steps, based on one-dimensional matching using usual correlation maximum. For the correlation calculation, the FFT is effectively used. Though some defects exist in the algorithm at present, close contour plotting to middle scale maps is available except in hilly regions, in which marked features in ground covers do not exist.