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com2real.c

Go to the documentation of this file.

#include        "sadie.h"

/*-Copyright Information------------------------------------------------------*/
/* Copyright (c) 1990 by the University of Arizona Digital Image Analysis Lab */
/*----------------------------------------------------------------------------*/
/*-General Information--------------------------------------------------------*/
/*                                                                            */
/*   This function separates one "complex" image into two "real" images.      */
/*                                                                            */
/*----------------------------------------------------------------------------*/
/*-Interface Information------------------------------------------------------*/
void COM2REAL (
IMAGE *in,      /*  I   Pointer to the input image.                           */
short option,   /*  I   Switch, indicating the type of real images:           */
                /*      REIMAG   -   real and imaginary images are computed.  */
                /*      MAGPHA   -   magnitude and phase images are computed. */
IMAGE **out1,   /*  O   Address of a pointer to the output image              */
                /*      containing the real/magnitude component.              */
IMAGE **out2    /*  O   Address of a pointer to the output image              */
                /*      containing the imaginary/phase component.             */
/*----------------------------------------------------------------------------*/
) { register short i, j, k, n;
    char   msg[SLEN];
    double re, im;

    if (TIMES) TIMING(T_COM2REAL);
    if (NAMES) {
        MESSAGE('I',"");
        MESSAGE('I',"COM2REAL");
        MESSAGE('I',"");
        sprintf(msg," Input image:  %s",in->text);
        MESSAGE('I',msg);
        if (option == REIMAG) {
            MESSAGE('I'," Real and imaginary images computed");
        } else if (option == MAGPHA) {
            MESSAGE('I'," Magnitude and phase images computed");
        }
        MESSAGE('I',"");
        MESSAGE('I'," ...............");
    }

    /* check input */
    if (!CHECKIMG(in)) {
        MESSAGE('E'," Can't identify image.");
        goto the_end;
    } else if (in->npix%2 != 0) {
        MESSAGE('E'," Number of pixels/line must be even.");
        goto the_end;
    } else if (option != REIMAG  &&  option != MAGPHA) {
        MESSAGE('E'," Option must be either REIMAG or MAGPHA.");
        goto the_end;
    }

    /* create image of appropriate size */
    if (!CHECKIMG(*out1)) GETMEM(in->nbnd,in->nlin,in->npix/2,out1);
    if (!*out1) goto the_end;
    if (!CHECKIMG(*out2)) GETMEM(in->nbnd,in->nlin,in->npix/2,out2);
    if (!*out2) goto the_end;

    if (option == REIMAG) {
        /* separate real and imaginary parts */
        for (i=0; i<in->nbnd; i++) {
            for (j=0; j<in->nlin; j++) {
                for (k=0,n=0; k<in->npix/2; k+=1,n+=2) {
                    (*out1)->data[i][j][k] = in->data[i][j][n];
                    (*out2)->data[i][j][k] = in->data[i][j][n+1];
                }
            }
        }
    } else /* (option == MAGPHA) */ {
        /* calculate magnitude and phase parts */
        for (i=0; i<in->nbnd; i++) {
            for (j=0; j<in->nlin; j++) {
                for (k=0,n=0; k<in->npix/2; k+=1,n+=2) {
                    re = (double)in->data[i][j][n];
                    im = (double)in->data[i][j][n+1];
                    (*out1)->data[i][j][k] = (PIXEL)sqrt((re*re + im*im));
                    if (re == 0.0) {
                        if (im > 0.0) {
                            (*out2)->data[i][j][k] = (PIXEL)(PI/2.0);
                        } else if (im < 0.0) {
                            (*out2)->data[i][j][k] = (PIXEL)(-PI/2.0);
                        } else /* (im == 0.0 ) */ {
                            (*out2)->data[i][j][k] = (PIXEL)0.0;
                        }
                    } else {
                        (*out2)->data[i][j][k] = (PIXEL)atan2(im,re);
                    }
                }
            }
        }
    }       

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

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