NAME

mkhratio -- generates hardness-ratio image


USAGE

mkhratio afile bfile outfile sclmode sclfact [nbins] amin bmin


DESCRIPTION

        This task generates a hardness ratio image from two images. Image A
        is the soft band, and Image B is the hard band.  The output image
        is basically composed of the values (B - A)/(B + A). The result
        corresponds to the range -1 to +1, which can be scaled by several 
        methods, such as a power of e, linearly, or binning into a linear
        histogram.  It is also possible to set a cut value for each image
        below which the pixel will be ignored.

PARAMETERS

afile (Image A file) [filename]
Location of file to consider as Image A, the soft band image.

bfile (Image B file) [filename]
Location of file to consider as Image B, the hard band image. Must be same size as Image A.

outfile [filename]
Location of the output image file. The header from Image A is copied into the output file.

sclmode (scaling mode: EXP, LINEAR, or HIST) [string]
Mode of scaling. 

                EXP:    sclfact*e^((B-A)/(B+A)) 
                LINEAR: sclfact*((B-A)/(B+A))
                HIST:   The values (B-A)/(B+A) are evenly partitioned into an 
                        'nbins' number of bins.  The resulting image contains
                        the bin number, which ranges from 1 to nbins.

If B+A = 0, the value in the output image is zero.

sclfact [real]
The scaling factor used to multiply the hardness ratio.

nbins [integer]
The number of bins used to partition the range of hardness ratios. Only applicable when sclmode=HIST.

amin [integer]
The minimum value of a pixel to use in Image A. Pixels below this value are assigned zero in the output image.

bmin [integer]
The minimum value of a pixel to use in Image B. Pixels below this value are assigned zero in the output image.

(tchat = 10) [integer]
Set terminal chattiness.

(lchat = 0) [integer]
Set log file and chattiness in the log file: = 0 the log file is not written.

(clobber = no) [boolean]
If true, an existing file with the same name as the requested output file will be overwritten.


EXAMPLES

           Generate a hardness ratio image with a linear scaling such that
           the resulting image contains values from 20 to 40, and pixels with
           less than 2 counts in each original image zeroed out in the final
           image.
          
             > mkhratio soft.img hard.img hr.img sclmode=linear sclfact=20 amin=2 bin=2


SEE ALSO

mkcolor

CATEGORY

mar00 ftools.mkhratio