mct.c

This document is intended to serve as an introduction to Wavelet processing through a set of Matlab

/*
 * Copyright (c) 2001-2002, David Janssens
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "mct.h"
#include "fix.h"

/* <summary> */
/* This table contains the norms of the basis function of the reversible MCT. */
/* </summary> */
double mct_norms[3]={1.732, .8292, .8292};

/* <summary> */
/* This table contains the norms of the basis function of the irreversible MCT. */
/* </summary> */
double mct_norms_real[3]={1.732, 1.805, 1.573};

/* <summary> */
/* Foward reversible MCT. */
/* </summary> */
void mct_encode(int *c0, int *c1, int *c2, int n)
{
    int i;
    for (i=0; i<n; i++) {
        int r, g, b, y, u, v;
        r=c0[i]; g=c1[i]; b=c2[i];
        y=(r+(g<<1)+b)>>2;
        u=b-g;
        v=r-g;
        c0[i]=y; c1[i]=u; c2[i]=v;
    }
}

/* <summary> */
/* Inverse reversible MCT. */
/* </summary> */
void mct_decode(int *c0, int *c1, int *c2, int n)
{
    int i;
    for (i=0; i<n; i++) {
        int y, u, v, r, g, b;
        y=c0[i]; u=c1[i]; v=c2[i];
        g=y-((u+v)>>2);
        r=v+g;
        b=u+g;
        c0[i]=r; c1[i]=g; c2[i]=b;
    }
}

/* <summary> */
/* Get norm of basis function of reversible MCT. */
/* </summary> */
double mct_getnorm(int compno) {
    return mct_norms[compno];
}

/* <summary> */
/* Foward irreversible MCT. */
/* </summary> */
void mct_encode_real(int *c0, int *c1, int *c2, int n)
{
    int i;
    for (i=0; i<n; i++) {
        int r, g, b, y, u, v;
        r=c0[i]; g=c1[i]; b=c2[i];
        y=fix_mul(r, 2449)+fix_mul(g, 4809)+fix_mul(b, 934);
        u=-fix_mul(r, 1382)-fix_mul(g, 2714)+fix_mul(b, 4096);
        v=fix_mul(r, 4096)-fix_mul(g, 3430)-fix_mul(b, 666);
        c0[i]=y; c1[i]=u; c2[i]=v;
    }
}

/* <summary> */
/* Inverse irreversible MCT. */
/* </summary> */
void mct_decode_real(int *c0, int *c1, int *c2, int n)
{
    int i;
    for (i=0; i<n; i++) {
        int y, u, v, r, g, b;
        y=c0[i]; u=c1[i]; v=c2[i];
        r=y+fix_mul(v, 11485);
        g=y-fix_mul(u, 2819)-fix_mul(v, 5850);
        b=y+fix_mul(u, 14516);
        c0[i]=r; c1[i]=g; c2[i]=b;
    }
}

/* <summary> */
/* Get norm of basis function of irreversible MCT. */
/* </summary> */
double mct_getnorm_real(int compno) {
    return mct_norms_real[compno];
}