imconv.h

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/*
Copyright (C) 2006 Pedro Felzenszwalb

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
*/

/* image conversion */

#pragma once

#include <climits>

#include "image.h"
#include "imutil.h"
#include "misc.h"

namespace distance_transform
{
  const double RED_WEIGHT = 0.299;
  const double GREEN_WEIGHT = 0.584;
  const double BLUE_WEIGHT = 0.114;

  static inline image<uchar> *imageRGBtoGRAY(image<rgb> *input) {
    int width = input->width();
    int height = input->height();
    image<uchar> *output = new image<uchar>(width, height, false);

    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        imRef(output, x, y) = (uchar)
    (imRef(input, x, y).r * RED_WEIGHT +
     imRef(input, x, y).g * GREEN_WEIGHT +
     imRef(input, x, y).b * BLUE_WEIGHT);
      }
    }
    return output;
  }

  static inline image<rgb> *imageGRAYtoRGB(image<uchar> *input) {
    int width = input->width();
    int height = input->height();
    image<rgb> *output = new image<rgb>(width, height, false);

    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        imRef(output, x, y).r = imRef(input, x, y);
        imRef(output, x, y).g = imRef(input, x, y);
        imRef(output, x, y).b = imRef(input, x, y);
      }
    }
    return output;  
  }

  static inline image<float> *imageUCHARtoFLOAT(image<uchar> *input) {
    int width = input->width();
    int height = input->height();
    image<float> *output = new image<float>(width, height, false);

    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        imRef(output, x, y) = imRef(input, x, y);
      }
    }
    return output;  
  }

  static inline image<float> *imageINTtoFLOAT(image<int> *input) {
    int width = input->width();
    int height = input->height();
    image<float> *output = new image<float>(width, height, false);

    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        imRef(output, x, y) = imRef(input, x, y);
      }
    }
    return output;  
  }

  static image<uchar> *imageFLOATtoUCHAR(image<float> *input, 
                 float min, float max) {
    int width = input->width();
    int height = input->height();
    image<uchar> *output = new image<uchar>(width, height, false);

    if (max == min)
      return output;

    float scale = UCHAR_MAX / (max - min);
    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        uchar val = (uchar)((imRef(input, x, y) - min) * scale);
        imRef(output, x, y) = bound(val, (uchar)0, (uchar)UCHAR_MAX);
      }
    }
    return output;
  }

  static inline image<uchar> *imageFLOATtoUCHAR(image<float> *input) {
    float min, max;
    min_max(input, &min, &max);
    return imageFLOATtoUCHAR(input, min, max);
  }

  static inline image<long> *imageUCHARtoLONG(image<uchar> *input) {
    int width = input->width();
    int height = input->height();
    image<long> *output = new image<long>(width, height, false);

    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        imRef(output, x, y) = imRef(input, x, y);
      }
    }
    return output;  
  }

  static image<uchar> *imageLONGtoUCHAR(image<long> *input, long min, long max) {
    int width = input->width();
    int height = input->height();
    image<uchar> *output = new image<uchar>(width, height, false);

    if (max == min)
      return output;

    float scale = UCHAR_MAX / (float)(max - min);
    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        uchar val = (uchar)((imRef(input, x, y) - min) * scale);
        imRef(output, x, y) = bound(val, (uchar)0, (uchar)UCHAR_MAX);
      }
    }
    return output;
  }

  static inline image<uchar> *imageLONGtoUCHAR(image<long> *input) {
    long min, max;
    min_max(input, &min, &max);
    return imageLONGtoUCHAR(input, min, max);
  }

  static image<uchar> *imageSHORTtoUCHAR(image<short> *input, 
            short min, short max) {
    int width = input->width();
    int height = input->height();
    image<uchar> *output = new image<uchar>(width, height, false);

    if (max == min)
      return output;

    float scale = UCHAR_MAX / (float)(max - min);
    for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
        uchar val = (uchar)((imRef(input, x, y) - min) * scale);
        imRef(output, x, y) = bound(val, (uchar)0, (uchar)UCHAR_MAX);
      }
    }
    return output;
  }

  static inline image<uchar> *imageSHORTtoUCHAR(image<short> *input) {
    short min, max;
    min_max(input, &min, &max);
    return imageSHORTtoUCHAR(input, min, max);
  }

} // namespace