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setmean.c

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#include        "sadie.h"
#include        "proto.h"


extern  PIXEL   gain;
extern  PIXEL   bias;

/*-Copyright Information------------------------------------------------------*/
/* Copyright (c) 1999 by the University of Arizona Digital Image Analysis Lab */
/*----------------------------------------------------------------------------*/
/*-General Information--------------------------------------------------------*/
/*                                                                            */
/*   This function stretches an image such that it has a given mean value.    */
/*                                                                            */
/*----------------------------------------------------------------------------*/
/*-Interface Information------------------------------------------------------*/
void SETMEAN (
IMAGE *in,      /*  I   Pointer to the input image.                           */
PIXEL mean,     /*  I   The desired resulting mean value.                     */
IMAGE **out     /*  O   Address of a pointer to the output image.             */
/*----------------------------------------------------------------------------*/
) { register short i, j, k;
    char   msg[SLEN];
    double sum, adj;

    if (TIMES) TIMING(T_RGBTOHSV);
    if (NAMES) {
        MESSAGE('I',"");
        MESSAGE('I',"SETMEAN");
        MESSAGE('I',"");
        sprintf(msg," Input image:   %s",in->text);
        MESSAGE('I',msg);
        MESSAGE('I'," ...............");
    }

    /* check input */
    if (!CHECKIMG(in)) {
        MESSAGE('E'," Can't identify image.");
        goto the_end;
    }

    for (i=0; i<in->nbnd; i++) {
        sum = 0.0;
        for (j=0; j<in->nlin; j++) {
            for (k=0; k<in->npix; k++) {
                sum += (double) in->data[i][j][k];
            }
        }
    }
    sum /= (double)(in->nbnd) * (double)(in->nlin) * (double)(in->npix);
    adj = (double)mean - sum;

    bias = (PIXEL) adj;
    gain = (PIXEL) 1.0;
    STRETCH(in, TFLINEAR, out);
    
    

    the_end:
    if (TIMES) TIMING(T_EXIT);
}

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