vpImageConvert.cpp

/*
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2024 by Inria. All rights reserved.
 *
 * This software 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.
 * See the file LICENSE.txt at the root directory of this source
 * distribution for additional information about the GNU GPL.
 *
 * For using ViSP with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * See https://visp.inria.fr for more information.
 *
 * This software was developed at:
 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 *
 * If you have questions regarding the use of this file, please contact
 * Inria at visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * Convert image types.
 */
 
#include <map>
#include <sstream>
 
#if defined(_OPENMP)
#include <omp.h>
#endif
 
 
#include <visp3/core/vpConfig.h>
 
#ifndef VISP_SKIP_BAYER_CONVERSION
#include "private/vpBayerConversion.h"
#endif
#include "private/vpImageConvert_impl.h"
#if defined(VISP_HAVE_SIMDLIB)
#include <Simd/SimdLib.h>
#endif
#include <visp3/core/vpImageConvert.h>
 
BEGIN_VISP_NAMESPACE
bool vpImageConvert::YCbCrLUTcomputed = false;
int vpImageConvert::vpCrr[256];
int vpImageConvert::vpCgb[256];
int vpImageConvert::vpCgr[256];
int vpImageConvert::vpCbb[256];
 
void vpImageConvert::convert(const vpImage<unsigned char> &src, vpImage<vpRGBa> &dest)
{
  dest.resize(src.getHeight(), src.getWidth());
 
  GreyToRGBa(src.bitmap, reinterpret_cast<unsigned char *>(dest.bitmap), src.getWidth(), src.getHeight());
}
 
void vpImageConvert::convert(const vpImage<vpRGBa> &src, vpImage<unsigned char> &dest, unsigned int nThreads)
{
  dest.resize(src.getHeight(), src.getWidth());
 
  RGBaToGrey(reinterpret_cast<unsigned char *>(src.bitmap), dest.bitmap, src.getWidth(), src.getHeight(), nThreads);
}
 
void vpImageConvert::convert(const vpImage<float> &src, vpImage<unsigned char> &dest)
{
  dest.resize(src.getHeight(), src.getWidth());
  unsigned int max_xy = src.getWidth() * src.getHeight();
  float min, max;
 
  src.getMinMaxValue(min, max);
 
  for (unsigned int i = 0; i < max_xy; ++i) {
    float val = 255.f * ((src.bitmap[i] - min) / (max - min));
    if (val < 0) {
      dest.bitmap[i] = 0;
    }
    else if (val > 255) {
      dest.bitmap[i] = 255;
    }
    else {
      dest.bitmap[i] = static_cast<unsigned char>(val);
    }
  }
}
 
void vpImageConvert::convert(const vpImage<vpRGBf> &src, vpImage<vpRGBa> &dest)
{
  const unsigned int srcHeight = src.getHeight(), srcWidth = src.getWidth();
  dest.resize(src.getHeight(), src.getWidth());
  vpRGBf min, max;
  src.getMinMaxValue(min, max);
 
  for (unsigned int i = 0; i < srcHeight; ++i) {
    for (unsigned int j = 0; j < srcWidth; ++j) {
      for (unsigned int c = 0; c < 3; ++c) {
        float val = 255.f * ((reinterpret_cast<const float *>(&(src[i][j]))[c] - reinterpret_cast<float *>(&min)[c]) /
                             (reinterpret_cast<float *>(&max)[c] - reinterpret_cast<float *>(&min)[c]));
        if (val < 0) {
          reinterpret_cast<unsigned char *>(&(dest[i][j]))[c] = 0;
        }
        else if (val > 255) {
          reinterpret_cast<unsigned char *>(&(dest[i][j]))[c] = 255;
        }
        else {
          reinterpret_cast<unsigned char *>(&(dest[i][j]))[c] = static_cast<unsigned char>(val);
        }
      }
    }
  }
}
 
void vpImageConvert::convert(const vpImage<unsigned char> &src, vpImage<float> &dest)
{
  const unsigned int srcHeight = src.getHeight(), srcWidth = src.getWidth();
  const unsigned int srcSize = srcHeight * srcWidth;
  dest.resize(srcHeight, srcWidth);
  for (unsigned int i = 0; i < srcSize; ++i) {
    dest.bitmap[i] = static_cast<float>(src.bitmap[i]);
  }
}
 
void vpImageConvert::convert(const vpImage<double> &src, vpImage<unsigned char> &dest)
{
  dest.resize(src.getHeight(), src.getWidth());
  unsigned int max_xy = src.getWidth() * src.getHeight();
  double min, max;
 
  src.getMinMaxValue(min, max);
 
  for (unsigned int i = 0; i < max_xy; ++i) {
    double val = 255. * ((src.bitmap[i] - min) / (max - min));
    if (val < 0) {
      dest.bitmap[i] = 0;
    }
    else if (val > 255) {
      dest.bitmap[i] = 255;
    }
    else {
      dest.bitmap[i] = static_cast<unsigned char>(val);
    }
  }
}
 
void vpImageConvert::convert(const vpImage<uint16_t> &src, vpImage<unsigned char> &dest, unsigned char bitshift)
{
  const unsigned int srcSize = src.getSize();
  dest.resize(src.getHeight(), src.getWidth());
 
  for (unsigned int i = 0; i < srcSize; ++i) {
    dest.bitmap[i] = static_cast<unsigned char>(src.bitmap[i] >> bitshift);
  }
}
 
void vpImageConvert::convert(const vpImage<unsigned char> &src, vpImage<uint16_t> &dest, unsigned char bitshift)
{
  const unsigned int srcSize = src.getSize();
  dest.resize(src.getHeight(), src.getWidth());
 
  for (unsigned int i = 0; i < srcSize; ++i) {
    dest.bitmap[i] = static_cast<unsigned char>(src.bitmap[i] << bitshift);
  }
}
 
void vpImageConvert::convert(const vpImage<unsigned char> &src, vpImage<double> &dest)
{
  const unsigned int srcHeight = src.getHeight(), srcWidth = src.getWidth();
  const unsigned int srcSize = srcHeight * srcWidth;
  dest.resize(srcHeight, srcWidth);
  for (unsigned int i = 0; i < srcSize; ++i) {
    dest.bitmap[i] = static_cast<double>(src.bitmap[i]);
  }
}
 
void vpImageConvert::createDepthHistogram(const vpImage<uint16_t> &src_depth, vpImage<vpRGBa> &dest_rgba)
{
  vp_createDepthHistogram(src_depth, dest_rgba);
}
 
void vpImageConvert::createDepthHistogram(const vpImage<uint16_t> &src_depth, vpImage<unsigned char> &dest_depth)
{
  vp_createDepthHistogram(src_depth, dest_depth);
}
 
void vpImageConvert::createDepthHistogram(const vpImage<float> &src_depth, vpImage<vpRGBa> &dest_rgba)
{
  vp_createDepthHistogram(src_depth, dest_rgba);
}
 
void vpImageConvert::createDepthHistogram(const vpImage<float> &src_depth, vpImage<unsigned char> &dest_depth)
{
  vp_createDepthHistogram(src_depth, dest_depth);
}
 
void vpImageConvert::RGBToRGBa(unsigned char *rgb, unsigned char *rgba, unsigned int size)
{
  RGBToRGBa(rgb, rgba, size, 1, false);
}
 
void vpImageConvert::RGBToRGBa(unsigned char *rgb, unsigned char *rgba, unsigned int width, unsigned int height,
                               bool flip)
{
#if defined(VISP_HAVE_SIMDLIB)
  if (!flip) {
    SimdBgrToBgra(rgb, width, height, width * 3, rgba, width * 4, vpRGBa::alpha_default);
  }
  else {
#endif
    // if we have to flip the image, we start from the end last scanline so the
    // step is negative
    int lineStep = flip ? -static_cast<int>(width * 3) : static_cast<int>(width * 3);
 
    // starting source address = last line if we need to flip the image
    unsigned char *src = flip ? (rgb + (width * height * 3) + lineStep) : rgb;
 
    unsigned int j = 0;
    unsigned int i = 0;
 
    for (i = 0; i < height; ++i) {
      unsigned char *line = src;
      for (j = 0; j < width; ++j) {
        *rgba++ = *(++line);
        *rgba++ = *(++line);
        *rgba++ = *(++line);
        *rgba++ = vpRGBa::alpha_default;
      }
      // go to the next line
      src += lineStep;
    }
#if defined(VISP_HAVE_SIMDLIB)
  }
#endif
}
 
void vpImageConvert::RGBaToRGB(unsigned char *rgba, unsigned char *rgb, unsigned int size)
{
#if defined(VISP_HAVE_SIMDLIB)
  SimdBgraToBgr(rgba, size, 1, size * 4, rgb, size * 3);
#else
  unsigned char *pt_input = rgba;
  unsigned char *pt_end = rgba + (4 * size);
  unsigned char *pt_output = rgb;
 
  while (pt_input != pt_end) {
    *(++pt_output) = *(++pt_input); // R
    *(++pt_output) = *(++pt_input); // G
    *(++pt_output) = *(++pt_input); // B
    ++pt_input;
  }
#endif
}
 
void vpImageConvert::RGBToGrey(unsigned char *rgb, unsigned char *grey, unsigned int size)
{
  RGBToGrey(rgb, grey, size, 1, false);
}
 
void vpImageConvert::RGBToGrey(unsigned char *rgb, unsigned char *grey, unsigned int width, unsigned int height,
                               bool flip)
{
#if defined(VISP_HAVE_SIMDLIB)
  if (!flip) {
    SimdRgbToGray(rgb, width, height, width * 3, grey, width);
  }
  else {
#endif
    // if we have to flip the image, we start from the end last scanline so
    // the  step is negative
    int lineStep = flip ? -static_cast<int>(width * 3) : static_cast<int>(width * 3);
 
    // starting source address = last line if we need to flip the image
    unsigned char *src = flip ? (rgb + (width * height * 3) + lineStep) : rgb;
 
    unsigned int j = 0;
    unsigned int i = 0;
 
    unsigned r, g, b;
 
    for (i = 0; i < height; ++i) {
      unsigned char *line = src;
      for (j = 0; j < width; ++j) {
        r = *(++line);
        g = *(++line);
        b = *(++line);
        *grey++ = static_cast<unsigned char>((0.2126 * r) + (0.7152 * g) + (0.0722 * b));
      }
 
      // go to the next line
      src += lineStep;
    }
#if defined(VISP_HAVE_SIMDLIB)
  }
#endif
}
 
void vpImageConvert::RGBaToGrey(unsigned char *rgba, unsigned char *grey, unsigned int width, unsigned int height,
                                unsigned int
#if defined(_OPENMP)
                                nThreads
#endif
)
{
#if defined(VISP_HAVE_SIMDLIB)
  const int heightAsInt = static_cast<int>(height);
#if defined(_OPENMP)
  if (nThreads > 0) {
    omp_set_num_threads(static_cast<int>(nThreads));
  }
#pragma omp parallel for
#endif
  for (int i = 0; i < heightAsInt; ++i) {
    SimdRgbaToGray(rgba + (i * width * 4), width, 1, width * 4, grey + (i * width), width);
  }
#else
#if defined(_OPENMP)
  (void)nThreads;
#endif
  vpImageConvert::RGBaToGrey(rgba, grey, width * height);
#endif
}
 
void vpImageConvert::RGBaToGrey(unsigned char *rgba, unsigned char *grey, unsigned int size)
{
#if defined(VISP_HAVE_SIMDLIB)
  SimdRgbaToGray(rgba, size, 1, size * 4, grey, size);
#else
  unsigned char *pt_input = rgba;
  unsigned char *pt_end = rgba + (size * 4);
  unsigned char *pt_output = grey;
 
  while (pt_input != pt_end) {
    *pt_output = static_cast<unsigned char>((0.2126 * (*pt_input)) + (0.7152 * (*(pt_input + 1))) + (0.0722 * (*(pt_input + 2))));
    pt_input += 4;
    ++pt_output;
  }
#endif
}
 
void vpImageConvert::GreyToRGBa(unsigned char *grey, unsigned char *rgba, unsigned int width, unsigned int height)
{
#if defined(VISP_HAVE_SIMDLIB)
  SimdGrayToBgra(grey, width, height, width, rgba, width * sizeof(vpRGBa), vpRGBa::alpha_default);
#else
  vpImageConvert::GreyToRGBa(grey, rgba, width * height);
#endif
}
 
void vpImageConvert::GreyToRGBa(unsigned char *grey, unsigned char *rgba, unsigned int size)
{
#if defined(VISP_HAVE_SIMDLIB)
  GreyToRGBa(grey, rgba, size, 1);
#else
  unsigned char *pt_input = grey;
  unsigned char *pt_end = grey + size;
  unsigned char *pt_output = rgba;
 
  while (pt_input != pt_end) {
    unsigned char p = *pt_input;
    *pt_output = p;                         // R
    *(pt_output + 1) = p;                     // G
    *(pt_output + 2) = p;                     // B
    *(pt_output + 3) = vpRGBa::alpha_default; // A
 
    ++pt_input;
    pt_output += 4;
  }
#endif
}
 
void vpImageConvert::GreyToRGB(unsigned char *grey, unsigned char *rgb, unsigned int size)
{
#if defined(VISP_HAVE_SIMDLIB)
  SimdGrayToBgr(grey, size, 1, size, rgb, size * 3);
#else
  unsigned char *pt_input = grey;
  unsigned char *pt_end = grey + size;
  unsigned char *pt_output = rgb;
 
  while (pt_input != pt_end) {
    unsigned char p = *pt_input;
    *pt_output = p;     // R
    *(pt_output + 1) = p; // G
    *(pt_output + 2) = p; // B
 
    ++pt_input;
    pt_output += 3;
  }
#endif
}
 
void vpImageConvert::BGRToRGBa(unsigned char *bgr, unsigned char *rgba, unsigned int width, unsigned int height,
                               bool flip)
{
#if defined(VISP_HAVE_SIMDLIB)
  if (!flip) {
    SimdRgbToBgra(bgr, width, height, width * 3, rgba, width * sizeof(vpRGBa), vpRGBa::alpha_default);
  }
  else {
#endif
    // if we have to flip the image, we start from the end last scanline so the
    // step is negative
    int lineStep = flip ? -static_cast<int>(width * 3) : static_cast<int>(width * 3);
 
    // starting source address = last line if we need to flip the image
    unsigned char *src = flip ? (bgr + (width * height * 3) + lineStep) : bgr;
 
    for (unsigned int i = 0; i < height; ++i) {
      unsigned char *line = src;
      for (unsigned int j = 0; j < width; ++j) {
        *rgba++ = *(line + 2);
        *rgba++ = *(line + 1);
        *rgba++ = *(line + 0);
        *rgba++ = vpRGBa::alpha_default;
 
        line += 3;
      }
      // go to the next line
      src += lineStep;
    }
#if defined(VISP_HAVE_SIMDLIB)
  }
#endif
}
 
void vpImageConvert::BGRaToRGBa(unsigned char *bgra, unsigned char *rgba, unsigned int width, unsigned int height,
                                bool flip)
{
#if defined(VISP_HAVE_SIMDLIB)
  if (!flip) {
    SimdBgraToRgba(bgra, width, height, width * 4, rgba, width * 4);
  }
  else {
#endif
    // if we have to flip the image, we start from the end last scanline so the
    // step is negative
    int lineStep = flip ? -static_cast<int>(width * 4) : static_cast<int>(width * 4);
 
    // starting source address = last line if we need to flip the image
    unsigned char *src = flip ? (bgra + (width * height * 4) + lineStep) : bgra;
 
    for (unsigned int i = 0; i < height; ++i) {
      unsigned char *line = src;
      for (unsigned int j = 0; j < width; ++j) {
        *rgba++ = *(line + 2);
        *rgba++ = *(line + 1);
        *rgba++ = *(line + 0);
        *rgba++ = *(line + 3);
 
        line += 4;
      }
      // go to the next line
      src += lineStep;
    }
#if defined(VISP_HAVE_SIMDLIB)
  }
#endif
}
 
void vpImageConvert::BGRToGrey(unsigned char *bgr, unsigned char *grey, unsigned int width, unsigned int height,
                               bool flip,
                               unsigned int
#if defined(_OPENMP)
                               nThreads
#endif
)
{
#if defined(VISP_HAVE_SIMDLIB)
  const int heightAsInt = static_cast<int>(height);
  if (!flip) {
#if defined(_OPENMP)
    if (nThreads > 0) {
      omp_set_num_threads(static_cast<int>(nThreads));
    }
#pragma omp parallel for
#endif
    for (int i = 0; i < heightAsInt; ++i) {
      SimdBgrToGray(bgr + (i * width * 3), width, 1, width * 3, grey + (i * width), width);
    }
  }
  else {
#endif
    // if we have to flip the image, we start from the end last scanline so
    // the  step is negative
    int lineStep = flip ? -static_cast<int>(width * 3) : static_cast<int>(width * 3);
 
    // starting source address = last line if we need to flip the image
    unsigned char *src = flip ? (bgr + (width * height * 3) + lineStep) : bgr;
 
    for (unsigned int i = 0; i < height; ++i) {
      unsigned char *line = src;
      for (unsigned int j = 0; j < width; ++j) {
        *grey++ = static_cast<unsigned int>((0.2126 * *(line + 2)) + (0.7152 * *(line + 1)) + (0.0722 * *(line + 0)));
        line += 3;
      }
 
      // go to the next line
      src += lineStep;
    }
#if defined(VISP_HAVE_SIMDLIB)
  }
#endif
#if !defined(VISP_HAVE_SIMDLIB) && defined(_OPENMP)
  (void)nThreads;
#endif
}
 
void vpImageConvert::BGRaToGrey(unsigned char *bgra, unsigned char *grey, unsigned int width, unsigned int height,
                                bool flip,
                                unsigned int
#if defined(_OPENMP)
                                nThreads
#endif
)
{
#if defined(VISP_HAVE_SIMDLIB)
  if (!flip) {
    const int heightAsInt = static_cast<int>(height);
#if defined(_OPENMP)
    if (nThreads > 0) {
      omp_set_num_threads(static_cast<int>(nThreads));
    }
#pragma omp parallel for
#endif
    for (int i = 0; i < heightAsInt; ++i) {
      SimdBgraToGray(bgra + (i * width * 4), width, 1, width * 4, grey + (i * width), width);
    }
  }
  else {
#endif
    // if we have to flip the image, we start from the end last scanline so
    // the  step is negative
    int lineStep = flip ? -static_cast<int>(width * 4) : static_cast<int>(width * 4);
 
    // starting source address = last line if we need to flip the image
    unsigned char *src = flip ? (bgra + (width * height * 4) + lineStep) : bgra;
 
    for (unsigned int i = 0; i < height; ++i) {
      unsigned char *line = src;
      for (unsigned int j = 0; j < width; ++j) {
        *grey++ = static_cast<unsigned char>((0.2126 * *(line + 2)) + (0.7152 * *(line + 1)) + (0.0722 * *(line + 0)));
        line += 4;
      }
 
      // go to the next line
      src += lineStep;
    }
#if defined(VISP_HAVE_SIMDLIB)
  }
#endif
#if !defined(VISP_HAVE_SIMDLIB) && defined(_OPENMP)
  (void)nThreads;
#endif
}
 
void vpImageConvert::computeYCbCrLUT()
{
  if (YCbCrLUTcomputed == false) {
    int index = 256;
 
    while (index--) {
 
      int aux = index - 128;
      vpImageConvert::vpCrr[index] = static_cast<int>((364.6610 * aux) / 256);
      vpImageConvert::vpCgb[index] = static_cast<int>((-89.8779 * aux) / 256);
      vpImageConvert::vpCgr[index] = static_cast<int>((-185.8154 * aux) / 256);
      vpImageConvert::vpCbb[index] = static_cast<int>((460.5724 * aux) / 256);
    }
 
    YCbCrLUTcomputed = true;
  }
}
 
void vpImageConvert::YCbCrToRGB(unsigned char *ycbcr, unsigned char *rgb, unsigned int size)
{
  unsigned char *cbv;
  unsigned char *crv;
  unsigned char *pt_ycbcr = ycbcr;
  unsigned char *pt_rgb = rgb;
  cbv = pt_ycbcr + 1;
  crv = pt_ycbcr + 3;
 
  vpImageConvert::computeYCbCrLUT();
 
  int col = 0;
 
  while (size--) {
    int val_r, val_g, val_b;
    if (!(col % 2)) {
      cbv = pt_ycbcr + 1;
      crv = pt_ycbcr + 3;
    }
 
    val_r = *pt_ycbcr + vpImageConvert::vpCrr[*crv];
    val_g = *pt_ycbcr + vpImageConvert::vpCgb[*cbv] + vpImageConvert::vpCgr[*crv];
    val_b = *pt_ycbcr + vpImageConvert::vpCbb[*cbv];
 
    *pt_rgb++ = (val_r < 0) ? 0u : ((val_r > 255) ? 255u : static_cast<unsigned char>(val_r)); // Red component.
    *pt_rgb++ = (val_g < 0) ? 0u : ((val_g > 255) ? 255u : static_cast<unsigned char>(val_g)); // Green component.
    *pt_rgb++ = (val_b < 0) ? 0u : ((val_b > 255) ? 255u : static_cast<unsigned char>(val_b)); // Blue component.
 
    pt_ycbcr += 2;
    ++col;
  }
}
 
void vpImageConvert::YCbCrToRGBa(unsigned char *ycbcr, unsigned char *rgba, unsigned int size)
{
  unsigned char *cbv;
  unsigned char *crv;
  unsigned char *pt_ycbcr = ycbcr;
  unsigned char *pt_rgba = rgba;
  cbv = pt_ycbcr + 1;
  crv = pt_ycbcr + 3;
 
  vpImageConvert::computeYCbCrLUT();
 
  int col = 0;
 
  while (size--) {
    int val_r, val_g, val_b;
    if (!(col % 2)) {
      cbv = pt_ycbcr + 1;
      crv = pt_ycbcr + 3;
    }
 
    val_r = *pt_ycbcr + vpImageConvert::vpCrr[*crv];
    val_g = *pt_ycbcr + vpImageConvert::vpCgb[*cbv] + vpImageConvert::vpCgr[*crv];
    val_b = *pt_ycbcr + vpImageConvert::vpCbb[*cbv];
 
    *pt_rgba++ = (val_r < 0) ? 0u : ((val_r > 255) ? 255u : static_cast<unsigned char>(val_r)); // Red component.
    *pt_rgba++ = (val_g < 0) ? 0u : ((val_g > 255) ? 255u : static_cast<unsigned char>(val_g)); // Green component.
    *pt_rgba++ = (val_b < 0) ? 0u : ((val_b > 255) ? 255u : static_cast<unsigned char>(val_b)); // Blue component.
    *pt_rgba++ = vpRGBa::alpha_default;
 
    pt_ycbcr += 2;
    ++col;
  }
}
 
void vpImageConvert::YCbCrToGrey(unsigned char *ycbcr, unsigned char *grey, unsigned int size)
{
  unsigned int i = 0, j = 0;
  const unsigned int doubleSize = size * 2;
  while (j < doubleSize) {
    grey[i++] = ycbcr[j];
    grey[i++] = ycbcr[j + 2];
    j += 4;
  }
}
 
void vpImageConvert::YCrCbToRGB(unsigned char *ycrcb, unsigned char *rgb, unsigned int size)
{
  unsigned char *cbv;
  unsigned char *crv;
  unsigned char *pt_ycbcr = ycrcb;
  unsigned char *pt_rgb = rgb;
  crv = pt_ycbcr + 1;
  cbv = pt_ycbcr + 3;
 
  vpImageConvert::computeYCbCrLUT();
 
  int col = 0;
 
  while (size--) {
    int val_r, val_g, val_b;
    if (!(col % 2)) {
      crv = pt_ycbcr + 1;
      cbv = pt_ycbcr + 3;
    }
 
    val_r = *pt_ycbcr + vpImageConvert::vpCrr[*crv];
    val_g = *pt_ycbcr + vpImageConvert::vpCgb[*cbv] + vpImageConvert::vpCgr[*crv];
    val_b = *pt_ycbcr + vpImageConvert::vpCbb[*cbv];
 
    *pt_rgb++ = (val_r < 0) ? 0u : ((val_r > 255) ? 255u : static_cast<unsigned char>(val_r)); // Red component.
    *pt_rgb++ = (val_g < 0) ? 0u : ((val_g > 255) ? 255u : static_cast<unsigned char>(val_g)); // Green component.
    *pt_rgb++ = (val_b < 0) ? 0u : ((val_b > 255) ? 255u : static_cast<unsigned char>(val_b)); // Blue component.
 
    pt_ycbcr += 2;
    ++col;
  }
}
 
void vpImageConvert::YCrCbToRGBa(unsigned char *ycrcb, unsigned char *rgba, unsigned int size)
{
  unsigned char *cbv;
  unsigned char *crv;
  unsigned char *pt_ycbcr = ycrcb;
  unsigned char *pt_rgba = rgba;
  crv = pt_ycbcr + 1;
  cbv = pt_ycbcr + 3;
 
  vpImageConvert::computeYCbCrLUT();
 
  int col = 0;
 
  while (size--) {
    int val_r, val_g, val_b;
    if (!(col % 2)) {
      crv = pt_ycbcr + 1;
      cbv = pt_ycbcr + 3;
    }
 
    val_r = *pt_ycbcr + vpImageConvert::vpCrr[*crv];
    val_g = *pt_ycbcr + vpImageConvert::vpCgb[*cbv] + vpImageConvert::vpCgr[*crv];
    val_b = *pt_ycbcr + vpImageConvert::vpCbb[*cbv];
 
    *pt_rgba++ = (val_r < 0) ? 0u : ((val_r > 255) ? 255u : static_cast<unsigned char>(val_r)); // Red component.
    *pt_rgba++ = (val_g < 0) ? 0u : ((val_g > 255) ? 255u : static_cast<unsigned char>(val_g)); // Green component.
    *pt_rgba++ = (val_b < 0) ? 0u : ((val_b > 255) ? 255u : static_cast<unsigned char>(val_b)); // Blue component.
    *pt_rgba++ = vpRGBa::alpha_default;
 
    pt_ycbcr += 2;
    ++col;
  }
}
 
void vpImageConvert::split(const vpImage<vpRGBa> &src, vpImage<unsigned char> *pR, vpImage<unsigned char> *pG,
                           vpImage<unsigned char> *pB, vpImage<unsigned char> *pa)
{
#if defined(VISP_HAVE_SIMDLIB)
  if (src.getSize() > 0) {
    if (pR) {
      pR->resize(src.getHeight(), src.getWidth());
    }
    if (pG) {
      pG->resize(src.getHeight(), src.getWidth());
    }
    if (pB) {
      pB->resize(src.getHeight(), src.getWidth());
    }
    if (pa) {
      pa->resize(src.getHeight(), src.getWidth());
    }
 
    unsigned char *ptrR = pR ? pR->bitmap : new unsigned char[src.getSize()];
    unsigned char *ptrG = pG ? pG->bitmap : new unsigned char[src.getSize()];
    unsigned char *ptrB = pB ? pB->bitmap : new unsigned char[src.getSize()];
    unsigned char *ptrA = pa ? pa->bitmap : new unsigned char[src.getSize()];
 
    SimdDeinterleaveBgra(reinterpret_cast<unsigned char *>(src.bitmap), src.getWidth() * sizeof(vpRGBa), src.getWidth(),
                         src.getHeight(), ptrR, src.getWidth(), ptrG, src.getWidth(), ptrB, src.getWidth(), ptrA,
                         src.getWidth());
 
    if (!pR) {
      delete[] ptrR;
    }
    if (!pG) {
      delete[] ptrG;
    }
    if (!pB) {
      delete[] ptrB;
    }
    if (!pa) {
      delete[] ptrA;
    }
  }
#else
  size_t n = src.getNumberOfPixel();
  unsigned int height = src.getHeight();
  unsigned int width = src.getWidth();
  unsigned char *input;
  unsigned char *dst;
  const unsigned int index_0 = 0;
  const unsigned int index_1 = 1;
  const unsigned int index_2 = 2;
  const unsigned int index_3 = 3;
 
  vpImage<unsigned char> *tabChannel[4];
 
  tabChannel[index_0] = pR;
  tabChannel[index_1] = pG;
  tabChannel[index_2] = pB;
  tabChannel[index_3] = pa;
 
  size_t i; /* ordre    */
  const unsigned int val_4 = 4;
  for (unsigned int j = 0; j < val_4; ++j) {
    if (tabChannel[j] != nullptr) {
      if ((tabChannel[j]->getHeight() != height) || (tabChannel[j]->getWidth() != width)) {
        tabChannel[j]->resize(height, width);
      }
      dst = static_cast<unsigned char *>(tabChannel[j]->bitmap);
 
      input = (unsigned char *)src.bitmap + j;
      i = 0;
      // optimization
      if (n >= 4) {
        n -= 3;
        for (; i < n; i += 4) {
          *dst = *input;
          input += 4;
          ++dst;
          *dst = *input;
          input += 4;
          ++dst;
          *dst = *input;
          input += 4;
          ++dst;
          *dst = *input;
          input += 4;
          ++dst;
        }
        n += 3;
      }
 
      for (; i < n; ++i) {
        *dst = *input;
        input += 4;
        ++dst;
      }
    }
  }
#endif
}
 
void vpImageConvert::merge(const vpImage<unsigned char> *R, const vpImage<unsigned char> *G,
                           const vpImage<unsigned char> *B, const vpImage<unsigned char> *a, vpImage<vpRGBa> &RGBa)
{
  // Check if the input channels have all the same dimensions
  std::map<unsigned int, unsigned int> mapOfWidths, mapOfHeights;
  if (R != nullptr) {
    ++mapOfWidths[R->getWidth()];
    ++mapOfHeights[R->getHeight()];
  }
 
  if (G != nullptr) {
    ++mapOfWidths[G->getWidth()];
    ++mapOfHeights[G->getHeight()];
  }
 
  if (B != nullptr) {
    ++mapOfWidths[B->getWidth()];
    ++mapOfHeights[B->getHeight()];
  }
 
  if (a != nullptr) {
    ++mapOfWidths[a->getWidth()];
    ++mapOfHeights[a->getHeight()];
  }
 
  if ((mapOfWidths.size() == 1) && (mapOfHeights.size() == 1)) {
    unsigned int width = mapOfWidths.begin()->first;
    unsigned int height = mapOfHeights.begin()->first;
 
    RGBa.resize(height, width);
 
 
#if defined(VISP_HAVE_SIMDLIB)
    if ((R != nullptr) && (G != nullptr) && (B != nullptr) && (a != nullptr)) {
      SimdInterleaveBgra(R->bitmap, width, G->bitmap, width, B->bitmap, width, a->bitmap, width, width, height,
                         reinterpret_cast<uint8_t *>(RGBa.bitmap), width * sizeof(vpRGBa));
    }
    else {
#endif
      unsigned int size = width * height;
      for (unsigned int i = 0; i < size; ++i) {
        if (R != nullptr) {
          RGBa.bitmap[i].R = R->bitmap[i];
        }
 
        if (G != nullptr) {
          RGBa.bitmap[i].G = G->bitmap[i];
        }
 
        if (B != nullptr) {
          RGBa.bitmap[i].B = B->bitmap[i];
        }
 
        if (a != nullptr) {
          RGBa.bitmap[i].A = a->bitmap[i];
        }
      }
#if defined(VISP_HAVE_SIMDLIB)
    }
#endif
  }
  else {
    throw vpException(vpException::dimensionError, "Mismatched dimensions!");
  }
}
 
void vpImageConvert::MONO16ToGrey(unsigned char *grey16, unsigned char *grey, unsigned int size)
{
  int i = (static_cast<int>(size) * 2) - 1;
  int j = static_cast<int>(size) - 1;
 
  while (i >= 0) {
    int y = grey16[i--];
    grey[j--] = static_cast<unsigned char>((y + (grey16[i] * 256)) / 256);
    --i;
  }
}
 
void vpImageConvert::MONO16ToRGBa(unsigned char *grey16, unsigned char *rgba, unsigned int size)
{
  int i = (static_cast<int>(size) * 2) - 1;
  int j = (static_cast<int>(size) * 4) - 1;
 
  while (i >= 0) {
    int y = grey16[i--];
    unsigned char v = static_cast<unsigned char>((y + (grey16[i] * 256)) / 256);
    --i;
    rgba[j--] = vpRGBa::alpha_default;
    rgba[j--] = v;
    rgba[j--] = v;
    rgba[j--] = v;
  }
}
 
// Bilinear
#ifndef VISP_SKIP_BAYER_CONVERSION
void vpImageConvert::demosaicBGGRToRGBaBilinear(const uint8_t *bggr, uint8_t *rgba, unsigned int width,
                                                unsigned int height, unsigned int nThreads)
{
  demosaicBGGRToRGBaBilinearTpl(bggr, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicBGGRToRGBaBilinear(const uint16_t *bggr, uint16_t *rgba, unsigned int width,
                                                unsigned int height, unsigned int nThreads)
{
  demosaicBGGRToRGBaBilinearTpl(bggr, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicGBRGToRGBaBilinear(const uint8_t *gbrg, uint8_t *rgba, unsigned int width,
                                                unsigned int height, unsigned int nThreads)
{
  demosaicGBRGToRGBaBilinearTpl(gbrg, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicGBRGToRGBaBilinear(const uint16_t *gbrg, uint16_t *rgba, unsigned int width,
                                                unsigned int height, unsigned int nThreads)
{
  demosaicGBRGToRGBaBilinearTpl(gbrg, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicGRBGToRGBaBilinear(const uint8_t *grbg, uint8_t *rgba, unsigned int width,
                                                unsigned int height, unsigned int nThreads)
{
  demosaicGRBGToRGBaBilinearTpl(grbg, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicGRBGToRGBaBilinear(const uint16_t *grbg, uint16_t *rgba, unsigned int width,
                                                unsigned int height, unsigned int nThreads)
{
  demosaicGRBGToRGBaBilinearTpl(grbg, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicRGGBToRGBaBilinear(const uint8_t *rggb, uint8_t *rgba, unsigned int width,
                                                unsigned int height, unsigned int nThreads)
{
  demosaicRGGBToRGBaBilinearTpl(rggb, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicRGGBToRGBaBilinear(const uint16_t *rggb, uint16_t *rgba, unsigned int width,
                                                unsigned int height, unsigned int nThreads)
{
  demosaicRGGBToRGBaBilinearTpl(rggb, rgba, width, height, nThreads);
}
 
// Malvar
 
void vpImageConvert::demosaicBGGRToRGBaMalvar(const uint8_t *bggr, uint8_t *rgba, unsigned int width,
                                              unsigned int height, unsigned int nThreads)
{
  demosaicBGGRToRGBaMalvarTpl(bggr, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicBGGRToRGBaMalvar(const uint16_t *bggr, uint16_t *rgba, unsigned int width,
                                              unsigned int height, unsigned int nThreads)
{
  demosaicBGGRToRGBaMalvarTpl(bggr, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicGBRGToRGBaMalvar(const uint8_t *gbrg, uint8_t *rgba, unsigned int width,
                                              unsigned int height, unsigned int nThreads)
{
  demosaicGBRGToRGBaMalvarTpl(gbrg, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicGBRGToRGBaMalvar(const uint16_t *gbrg, uint16_t *rgba, unsigned int width,
                                              unsigned int height, unsigned int nThreads)
{
  demosaicGBRGToRGBaMalvarTpl(gbrg, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicGRBGToRGBaMalvar(const uint8_t *grbg, uint8_t *rgba, unsigned int width,
                                              unsigned int height, unsigned int nThreads)
{
  demosaicGRBGToRGBaMalvarTpl(grbg, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicGRBGToRGBaMalvar(const uint16_t *grbg, uint16_t *rgba, unsigned int width,
                                              unsigned int height, unsigned int nThreads)
{
  demosaicGRBGToRGBaMalvarTpl(grbg, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicRGGBToRGBaMalvar(const uint8_t *rggb, uint8_t *rgba, unsigned int width,
                                              unsigned int height, unsigned int nThreads)
{
  demosaicRGGBToRGBaMalvarTpl(rggb, rgba, width, height, nThreads);
}
 
void vpImageConvert::demosaicRGGBToRGBaMalvar(const uint16_t *rggb, uint16_t *rgba, unsigned int width,
                                              unsigned int height, unsigned int nThreads)
{
  demosaicRGGBToRGBaMalvarTpl(rggb, rgba, width, height, nThreads);
}
#endif // VISP_SKIP_BAYER_CONVERSION
 
END_VISP_NAMESPACE