Search Window Size
Once an interest point or feature point has been identified on the first
image in a block, LPS ATE estimates the approximate location of the
same feature point on the neighboring second image. When an
approximate location has been identified, LPS ATE searches for the
corresponding image positions within a rectangular search window.
The search window X defines the search area length along the
epipolar line; the search window size Y defines the search area width
across the epipolar line. The search window size X reflects the
variation of ground elevations for that given window appearing on
the surface of the Earth. The larger the range of ground elevation,
the larger the search window size X.
For aerial frame camera images with good triangulation results, the
epipolar line can be computed quite accurately; therefore, one to
three pixels for the search window size Y are sufficient. For
pushbroom images, the epipolar lines are less accurate, and three to
five pixels are recommended. If the triangulation results are not
good, the search window size Y should be increased further.
Figure 3 shows an ideal situation for aerial frame images where the
images are horizontal (no omega and phi), and the two image
exposure centers are at the same height.