Isis 2 Documentation
equalizer - Write PDF to correct brightness differences between cubes EQUALIZER uses the PHOTO_RAD_POINTs from the cube labels to find a best fit for brightness corrections to remove seams between cubes. A procedure is created by this program to apply the corrections to each of the cubes. The report written to the log file provides an indication as to how successful the program was. It contains a table listing the image numbers, averages, ratio, difference between the updated averages (ADD ERR), and 1 - the updated ratio (MULT ERR) for each of the overlap areas. The dn values are adjusted as follows: ADD only: newdn = olddn + ADD MULT only: newdn = (olddn - photomean)*MULT + photomean BOTH: newdn = (olddn - photomean)*MULT + photomean + ADD In the MULT only and BOTH cases, the ADD term absorbs the photomean terms. PROGRAMMERS: Kay Edwards and Debbie Cook, U.S.G.S., Flagstaff, Arizona
Parm | Description | Default |
---|---|---|
FROM | Input cube file names or | "" |
FROMLIST | List of input cube file names | "" |
HOLD | Hold file names or | "" |
HOLDLIST | List of hold file names | "" |
TO | Name of PDF to be created | temp.pdf |
FITOPT | 1 -> MULT 2 -> ADD 3 -> MULT & ADD | 3 |
TOL | Tolerance for gain ratios | .5 |
ALPHA | Arbitrary constant for LSF | 1000. |
MINCOUNT | Minimum number of points in overlap area required to be used in the solution. |
ADDITIONAL NOTES:
Parm | Description |
---|---|
FROM | List of cubes that are to be compared. These cubes must have PHOTO_RAD_POINTs in the labels to be used by this program. A maximum of 50 cubes may be listed here. If more are needed, use FROMLIST. |
FROMLIST | ASCII file containing the list of cubes to be processed by this program. List one cube per line. Up to 1000 cubes may be listed. |
HOLD | List of cubes that are to be held. The PHOTO_RAD_POINTs in the labels are used to influence the solution, but the camera angles are not changed on held images. A maximum of 50 cubes may be listed here. If more are needed, use HOLDLIST. |
HOLDLIST | ASCII file containing the list of cubes to be held by this program. List one cube per line. Up to 1000 cubes may be listed. See HOLD for more information. |
TO | This is the name of a PDF that will be created by this program. This PDF will apply the actual corrections to the cubes using the program "poly". The input cubes will have ".l4" appended to the file name to create the output file names. An additive and a multiplicative factor will be applied to all cubes that were not held constant. |
FITOPT | Choose the fit option to select the algorithm to use to adjust the pixel values. Note that due to the nature of the fit equations, an add will be used in "poly" even when the MULT only option is selected. |
TOL | This value is used to judge the gain ratios between images. Any point with a ratio outside the range between TOL and 1/TOL is ignored. |
ALPHA | An arbitrary constant to remove the indeterminacy of the least squares solution. A large ALPHA allows the brightness values to change more. A small ALPHA holds closer to the current brightness values. |
MINCOUNT | If the number of points in the overlap area meets or exceeds this value, the area will go into the solution. Otherwise the overlap area will be weighted 0 and essentially ignored. |
Contact us online at the Isis Support Center: http://isisdist.wr.usgs.gov