USGS MIPS Ratcmbo Documentation

USGS MIPS Ratcmbo Documentation

This program generates a ratio composed of any combination of two to four images . It allows the user to multiply each image by a constant (positive or negative) before ratioing. If the user wants only one file divided by a second file, he/she should use the program RATIO because it is faster and easier to use. The following equation is used to calculate the output DN s:

       
         ((n1*I1 + n2*I2 + n3*I3 + n4*I4) * mult)
Output = ---------------------------------------- + addback
             (d1*I1 + d2*I2 + d3*I3 + d4*I4)

where,

I(i) is the ith input image
n(i) is the ith numerator coefficient
d(i) is the ith denomiator coefficient
Mult is a multiplicative constant
Addback is an additive constant

The coefficients, multiplicaive and addback are specified by the user and can be any real number.

Files

This program requires as input two to four unsigned 8-bit image files and will produce one unsigned 8-bit image. The following information is transferred from the first input file to the output file(if appropriate):

Image labels
Mosaic labels
Projection labels
Sonar labels
Navigation file
History file

Parameters

NCOEF and DCOEF: These parameters are arrays for setting the coefficients for the numerator and denominator of the equation. For example, if three input images were entered then each array would have three elements, NCOEF1, NCOEF2, NCOEF3, and DCOEF1, DCOEF2, DCOEF3.
MULT: This parameter is a multiplicative constant and defaults to 100.0. Mult is used to keep the output DNs in the proper range for the unsigned 8-bit image (i.e., 0 to 255).
ADDBACK: This parameter is an additive constant which defaults to zero. Addback is used to keep the output DNs in the proper range for the unsigned 8-bit image (i.e., 0 to 255).

Uses

This program can be used to generate any of the vegatation indexes (e.g., the NDVI is generated by using the red and near-infrared spectral bands as input and setting n1 = 1.0, n2 = -1.0, d1 = 1.0, and d2 = 1.0).

Another use of this program is to generate a normalized ratio (e.g, by running this program 3 times and using the following parameters: n1 = 1.0, n2 = n3 = 0.0, and d1 = d2 = d3 = 1.0; then n1 = n3 = 0.0, n2 = 1.0 and d1 = d2 = d3 = 1.0; then n1 = n2 = 0.0, n3 = 1.0 and n1 = n3 = 0.0; a color composite can be created which is shown in the example below).

Examples

From left to right, original Landsat TM Bands 2, 4 and 5.

[Example Image]

From left to right, ratios for Landsat TM Bands 2, 4 and 5 normalized to their sum. In the first image, Landsat TM Band 2 was used as the numerator and the Landsat TM Bands 2-4-5 were used as the denominator. In the second and third images, Landsat TM Bands 4 and 5 were used as the numerator, respectively, while Landsat TM Bands 2-4-5 were again used as the denominator.

[Example Image]

Color composite of the three ratios shown above; where Landsat TM Band 2 was normalized through the blue channel, Landsat TM Band 4 was normalized through the green channel and Landsat TM Band 5 was normalized through the red channel. This three ratios were contrast stretched before color compositing.

[Example Image]