"ml" stands for multilook. To make a square field look square in a SAR image, you must multilook the image.
This is necessary because SAR satellites generally have smaller pixels in one direction than the other. For example, ERS-1's pixels are about 20m on the ground in range, and just 4m on the ground in azimuth. Thus, for 20m by 20m pixels, we have to multilook ERS-1 images by a factor of 5.
The multilook program lets you specify the "step" and "look" sizes: the step size is the distance between input pixels for each output pixel; the look size is the number of input pixels added together for each output pixel. For ERS-1, we usually use a 5x1 step and a 5x1 look. This means each output pixel is the sum of 5 lines of input pixels, and each output pixel starts 5 lines further down in the input.
The multilook program also generates a colorized LAS image of the interferogram.
Ml is usually called by tandem_ifm, but can be run alone.
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Last Updated: September 1, 1998
If you have any questions, please feel free to email olawlor@acm.org