USGS MIPS Slr2gr Docmentation

USGS MIPS Slr2gr Documentation

This program corrects for both water column and slant range geometry problems in a sidescan sonar image (i.e., it removes the blank/non-bottom pixels at the center of the sonar image(water column) and transforms pixels whose positions are based on time/slant range geometry to ground range positions/geometry).

Files

This program requires as input one unsigned 8-bit or one signed 16-bit sonar image file and produces an output image of the same bit type. The following information is transferred from the input file to the output file(if appropriate):

Image labels
Sonar labels
Navigation file
History file

Note the input image must be a sidescan sonar image with a merged navigation file associated with it.

Parameters

PIXRES: This parameter identifies the desired output ground range pixel resolution in the across track direction. The resolution is in meters per pixel and has no default value, however, the resolution used here must also be used in the program DELTAV to get a square pixel.
NANGLE and FANGLE: These are the near- and far-range depression angles. A depression angle starts at 0 degrees from the horizontal plane intersecting the sonar imaging system and increases to 90 degrees at nadir (i.e., the point just below the sonar imaging system). These angles are used to select which data are to be included in the output file. The default values are 90 degrees for NANGLE and 0.5 degrees for FANGLE; these values keep all data/pixels. Decreasing the near range or increasing the far range angle will cause data/pixels to be thrown out at the corresponding edge.
LOFFSET and ROFFSET: These offsets are used to make minor adjustments to the water column removal. The number of pixels in the water column is based on the altitude of the sonar imaging system above the sea floor; because of errors in the fish altitudes the water column correction can remove part of the image or not enough of the water column. These offsets allow the user to increase the number of pixels in the water column for the left, right, or both. The default values are 0 and are typically used on most images.

Uses

This program is used to convert from slant-range to ground-range geometry and is essential for creating digital sonar mosaics.

Examples

Gloria sonar image before slant-range to ground-range and water column corrections.

[Example Image]

Gloria sonar image after slant-range to ground-range and water column corrections.

USGS MIPS Slr2gr Documentation

Files

Parameters

Uses

Examples

See Also