YINSAR and YSAR IMAGES - Interpretation and Naming
The BYU Synthetic Aperature Radar Systems
YINSAR Image Interpretation
YINSAR images are most often presented as a vertical strip. This orientation
corresponds to the plane flying down the page, with the radar looking
to the right of the image (the radar looks left from the point of
view of someone sitting in the airplane).
One may notice there is considerable variation in the apparent image
quality in the images presented. This is caused by variations in the
amount of unwanted aircraft motion, the accuracy of velocity measurements,
and by the terrain itself (some areas just don't look as nice).
Any images presented on the web without an indication of pixel size
are approximately 1.2m x 2.4m images. High-resolution images are 0.6m
x 0.6m. The auto-generated web pages have various size images, with
square pixels whose size is indicated. The images are averaged in
both directions to give these pixel sizes in the range direction (across
the page) and the azimuth direction (down the page) (since azimuth
pixel size depends on velocity, the azimuth pixel size may not be
exact).
YSAR Image Interpretation
YSAR Images are most often presented as a vertical strip. This orientation
corresponds to the plane flying down the page, with the radar looking
to the left of the image (the radar looks right from the point of
view of someone sitting in the airplane). In most cases, there is
a black strip of varying width in the near range. This is because
we start sampling before the nadir return comes back to the radar.
The width of this pre-nadir region varies because of variations in
both the altitude of the aircraft and the topography of the ground.
The images presented on the web are all 64-look images. They have
been averaged to 4 looks in range and 16 in azimuth. This results
in pixels approximately square, with about 2.5 meters on a side.
Image Naming
YSAR and YINSAR images are named for the time of day at which the
data was collected. For example, Pass 1200 was collected at noon on
a given day. Thus the images from two different day's data collection
may have the same name.
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