testConversion.cpp

/****************************************************************************
 *
 * This file is part of the ViSP software.
 * Copyright (C) 2005 - 2017 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
 * ("GPL") version 2 as published by the Free Software Foundation.
 * 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 http://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:
 * Test for image conversions.
 *
 * Authors:
 * Fabien Spindler
 *
 *****************************************************************************/

#include <stdlib.h>
#include <iomanip>

#include <visp3/core/vpConfig.h>
#include <visp3/core/vpImage.h>
#include <visp3/io/vpImageIo.h>
#include <visp3/core/vpImageConvert.h>
#include <visp3/io/vpParseArgv.h>
#include <visp3/core/vpIoTools.h>
#include <visp3/core/vpDebug.h>
#include <visp3/core/vpTime.h>


// List of allowed command line options
#define GETOPTARGS  "cdi:o:n:h"


/*
  Print the program options.

  \param name : Program name.
  \param badparam : Bad parameter name.
  \param ipath: Input image path.
  \param opath : Output image path.
  \param user : Username.
  \param nbiter : Iteration number.

 */
void usage(const char *name, const char *badparam, std::string ipath, std::string opath, std::string user, int nbiter)
{
  fprintf(stdout, "\n\
Test image conversions.\n\
\n\
SYNOPSIS\n\
  %s [-i <input image path>] [-o <output image path>] [-n <nb benchmark iterations>]\n\
     [-h]\n                           \
", name);

  fprintf(stdout, "\n\
OPTIONS:                                               Default\n\
  -i <input image path>                                %s\n\
     Set image input path.\n\
     From this path read \"ViSP-images/Klimt/Klimt.pgm\"\n\
     and \"ViSP-images/Klimt/Klimt.ppm\" images.\n\
     Setting the VISP_INPUT_IMAGE_PATH environment\n\
     variable produces the same behaviour than using\n\
     this option.\n\
\n\
  -o <output image path>                               %s\n\
     Set image output path.\n\
     From this directory, creates the \"%s\"\n\
     subdirectory depending on the username, where \n\
     Klimt_grey.pgm and Klimt_color.ppm output images\n\
     are written.\n\
\n\
  -n <nb benchmark iterations>                               %d\n\
     Set the number of benchmark iterations.\n\
\n\
  -h\n\
     Print the help.\n\n",
    ipath.c_str(), opath.c_str(), user.c_str(), nbiter);

  if (badparam)
    fprintf(stdout, "\nERROR: Bad parameter [%s]\n", badparam);
}

bool getOptions(int argc, const char **argv, std::string &ipath, std::string &opath, std::string user,
                int &nbIterations)
{
  const char *optarg_;
  int   c;
  while ((c = vpParseArgv::parse(argc, argv, GETOPTARGS, &optarg_)) > 1) {

    switch (c) {
    case 'i': ipath = optarg_; break;
    case 'o': opath = optarg_; break;
    case 'n': nbIterations = atoi(optarg_); break;
    case 'h': usage(argv[0], NULL, ipath, opath, user, nbIterations); return false; break;

    case 'c':
    case 'd':
      break;

    default:
      usage(argv[0], optarg_, ipath, opath, user, nbIterations); return false; break;
    }
  }

  if ((c == 1) || (c == -1)) {
    // standalone param or error
    usage(argv[0], NULL, ipath, opath, user, nbIterations);
    std::cerr << "ERROR: " << std::endl;
    std::cerr << "  Bad argument " << optarg_ << std::endl << std::endl;
    return false;
  }

  return true;
}

void computeRegularRGBaToGrayscale(const unsigned char* rgba, unsigned char* grey, unsigned int size) {
  const unsigned char *pt_input = rgba;
  const unsigned char *pt_end = rgba + size*4;
  unsigned char *pt_output = grey;

  while(pt_input != pt_end) {
    *pt_output = (unsigned char) (0.2126 * (*pt_input)
      + 0.7152 * (*(pt_input + 1))
      + 0.0722 * (*(pt_input + 2)) );
    pt_input += 4;
    pt_output ++;
  }
}

void computeRegularRGBToGrayscale(const unsigned char* rgb, unsigned char* grey, unsigned int size) {
  const unsigned char *pt_input = rgb;
  const unsigned char* pt_end = rgb + size*3;
  unsigned char *pt_output = grey;

  while(pt_input != pt_end) {
    *pt_output = (unsigned char) (0.2126 * (*pt_input)
      + 0.7152 * (*(pt_input + 1))
      + 0.0722 * (*(pt_input + 2)) );
    pt_input += 3;
    pt_output ++;
  }
}

void computeRegularBGRToGrayscale(unsigned char * bgr, unsigned char * grey,
                                  unsigned int width, unsigned int height, bool flip) {
  //if we have to flip the image, we start from the end last scanline so the
  //step is negative
  int lineStep = (flip) ? -(int)(width*3) : (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;

  unsigned int j=0;
  unsigned int i=0;

  for(i=0 ; i < height ; i++)
  {
    unsigned char *line = src;
    for( j=0 ; j < width ; j++)
    {
      *grey++ = (unsigned char)( 0.2126 * *(line+2)
         + 0.7152 * *(line+1)
         + 0.0722 * *(line+0)) ;
      line+=3;
    }

    //go to the next line
    src+=lineStep;
  }
}

#if (VISP_HAVE_OPENCV_VERSION >= 0x020101)
void computeRegularBGRToGrayscale(const cv::Mat& src, vpImage<unsigned char>& dest)
{
  if(src.type() == CV_8UC3) {
    dest.resize((unsigned int)src.rows, (unsigned int)src.cols);

    if(src.isContinuous()) {
      computeRegularBGRToGrayscale((unsigned char*)src.data, (unsigned char*)dest.bitmap, (unsigned int)src.cols, (unsigned int)src.rows, false);
    }
  }
}
#endif

int
main(int argc, const char ** argv)
{
  try {
    std::string env_ipath;
    std::string opt_ipath;
    std::string opt_opath;
    std::string ipath;
    std::string opath;
    std::string filename;
    std::string username;
    int nbIterations = 100;

    // Get the visp-images-data package path or VISP_INPUT_IMAGE_PATH environment variable value
    env_ipath = vpIoTools::getViSPImagesDataPath();

    // Set the default input path
    if (! env_ipath.empty())
      ipath = env_ipath;

    // Set the default output path
#if defined(_WIN32)
    opt_opath = "C:/temp";
#else
    opt_opath = "/tmp";
#endif

    // Get the user login name
    vpIoTools::getUserName(username);

    // Read the command line options
    if (getOptions(argc, argv, opt_ipath, opt_opath, username, nbIterations) == false) {
      exit (-1);
    }

    // Get the option values
    if (!opt_ipath.empty())
      ipath = opt_ipath;
    if (!opt_opath.empty())
      opath = opt_opath;

    // Append to the output path string, the login name of the user
    opath = vpIoTools::createFilePath(opath, username);

    // Test if the output path exist. If no try to create it
    if (vpIoTools::checkDirectory(opath) == false) {
      try {
        // Create the dirname
        vpIoTools::makeDirectory(opath);
      }
      catch (...) {
        usage(argv[0], NULL, ipath, opt_opath, username, nbIterations);
        std::cerr << std::endl
                  << "ERROR:" << std::endl;
        std::cerr << "  Cannot create " << opath << std::endl;
        std::cerr << "  Check your -o " << opt_opath << " option " << std::endl;
        exit(-1);
      }
    }

    // Compare ipath and env_ipath. If they differ, we take into account
    // the input path comming from the command line option
    if (opt_ipath.empty()) {
      if (ipath != env_ipath) {
        std::cout << std::endl
                  << "WARNING: " << std::endl;
        std::cout << "  Since -i <visp image path=" << ipath << "> "
                  << "  is different from VISP_IMAGE_PATH=" << env_ipath << std::endl
                  << "  we skip the environment variable." << std::endl;
      }
    }

    // Test if an input path is set
    if (opt_ipath.empty() && env_ipath.empty()){
      usage(argv[0], NULL, ipath, opt_opath, username, nbIterations);
      std::cerr << std::endl
                << "ERROR:" << std::endl;
      std::cerr << "  Use -i <visp image path> option or set VISP_INPUT_IMAGE_PATH "
                << std::endl
                << "  environment variable to specify the location of the " << std::endl
                << "  image path where test images are located." << std::endl << std::endl;
      exit(-1);
    }

    //
    // Here starts really the test
    //

    vpImage<unsigned char> Ig ; // Grey image
    vpImage<vpRGBa> Ic ; // Color image

    //-------------------- .pgm -> .ppm
    std::cout << "** Convert a grey image (.pgm) to a color image (.ppm)" << std::endl;
    // Load a grey image from the disk
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.pgm");
    std::cout << "   Load " <<  filename << std::endl;
    vpImageIo::read(Ig, filename) ;
    // Create a color image from the grey
    vpImageConvert::convert(Ig, Ic);
    filename = vpIoTools::createFilePath(opath, "Klimt_color.ppm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ic, filename) ;

    //-------------------- .ppm -> .pgm
    std::cout << "** Convert a color image (.ppm) to a grey image (.pgm)" << std::endl;
    // Load a color image from the disk
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");
    std::cout << "   Load " << filename << std::endl;
    vpImageIo::read(Ic, filename) ;
    // Create a grey image from the color
    vpImageConvert::convert(Ic, Ig);
    filename = vpIoTools::createFilePath(opath, "Klimt_grey.pgm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ig, filename) ;

    //-------------------- YUV -> RGB
    std::cout << "** Convert YUV pixel value to a RGB value" << std::endl;
    unsigned char y=187, u=10, v=30;
    unsigned char r, g, b;

    // Convert a YUV pixel value to a RGB value
    vpImageConvert::YUVToRGB(y, u, v, r, g, b);
    std::cout << "   y(" << (int)y << ") u("<< (int)u << ") v(" << (int)v << ") = r(" << (int)r << ") g(" << (int)g << ") b(" << (int)b << ")" << std::endl;

#ifdef VISP_HAVE_OPENCV
#if VISP_HAVE_OPENCV_VERSION < 0x020408
    double t0 = vpTime::measureTimeMs();
    // Convert a IplImage to a vpImage<vpRGBa>
    std::cout << "** Convert an IplImage to a vpImage<vpRGBa>" << std::endl;
    IplImage* image = NULL; 
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");

    /* Read the color image */

    std::cout << "   Reading the color image with opencv: "<< filename << std::endl;
    if((image = cvLoadImage(filename.c_str(), CV_LOAD_IMAGE_COLOR)) == NULL) {
      std::cout << "   Cannot read image: "<< filename << std::endl;
      return (-1);
    }
    vpImageConvert::convert(image, Ic);
    filename = vpIoTools::createFilePath(opath, "Klimt_color_cv.ppm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ic, filename) ;

    std::cout << "   Convert result in " << filename << std::endl;

    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.pgm");

    /* Read the pgm image */
    std::cout << "   Reading the greyscale image with opencv: " << filename << std::endl;
    if(image!=NULL) cvReleaseImage( &image );
    if((image = cvLoadImage(filename.c_str(), CV_LOAD_IMAGE_GRAYSCALE)) == NULL) {
      std::cout << "   Cannot read image: " << filename << std::endl;
      return (-1);
    }
    vpImageConvert::convert(image, Ic);
    filename = vpIoTools::createFilePath(opath, "Klimt_grey_cv.ppm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ic, filename) ;

    std::cout << "   Convert result in " << filename << std::endl;

    // Convert a IplImage to a vpImage<unsigned char>
    std::cout << "** Convert an IplImage to a vpImage<unsigned char>" << std::endl;
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");

    /* Read the color image */

    std::cout << "   Reading the color image with opencv: "<< filename << std::endl;
    if(image!=NULL) cvReleaseImage( &image );
    if((image = cvLoadImage(filename.c_str(), CV_LOAD_IMAGE_COLOR)) == NULL) {
      std::cout << "   Cannot read image: "<< filename << std::endl;
      return (-1);
    }
    vpImageConvert::convert(image, Ig);
    filename = vpIoTools::createFilePath(opath, "Klimt_color_cv.pgm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ig, filename) ;

    std::cout << "   Convert result in " << filename << std::endl;

    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.pgm");

    /* Read the pgm image */

    std::cout << "   Reading the greyscale image with opencv: " << filename << std::endl;
    if(image!=NULL) cvReleaseImage( &image );
    if((image = cvLoadImage(filename.c_str(), CV_LOAD_IMAGE_GRAYSCALE)) == NULL) {
      std::cout << "   Cannot read image: "<< filename << std::endl;
      return (-1);
    }
    vpImageConvert::convert(image, Ig);
    filename = vpIoTools::createFilePath(opath, "Klimt_grey_cv.pgm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ig, filename) ;

    std::cout << "   Convert result in " << filename << std::endl;

    // Convert a vpImage<vpRGBa> to a IplImage
    std::cout << "** Convert a vpImage<vpRGBa> to an IplImage" << std::endl;
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");

    /* Read the color image */

    // Load a color image from the disk
    std::cout << "   Load " << filename << std::endl;
    vpImageIo::read(Ic, filename) ;
    vpImageConvert::convert(Ic, image);
    filename = vpIoTools::createFilePath(opath, "Klimt_ipl_color_cv.ppm");
    /* Save the the current image */
    std::cout << "   Write " << filename << std::endl;
    if((cvSaveImage(filename.c_str(), image)) == 0) {
      std::cout << "   Cannot write image: " << filename << std::endl;
      if(image!=NULL) cvReleaseImage( &image );
      return (-1);
    }
    std::cout << "   Convert result in " << filename << std::endl;

    // Convert a vpImage<unsigned char> to an IplImage
    std::cout << "** Convert a vpImage<unsigned char> to an IplImage" << std::endl;
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.pgm");

    /* Read the grey image */

    // Load a color image from the disk
    std::cout << "   Load " << filename << std::endl;
    vpImageIo::read(Ig, filename) ;
    vpImageConvert::convert(Ig, image);
    filename = vpIoTools::createFilePath(opath, "Klimt_ipl_grey_cv.pgm");
    /* Save the the current image */

    std::cout << "   Write " << filename << std::endl;
    if((cvSaveImage(filename.c_str(), image)) == 0) {
      std::cout << "   Cannot write image: "<< std::endl << filename << std::endl;
      if(image!=NULL) cvReleaseImage( &image );
      return (-1);
    }
    std::cout << "   Convert result in " << filename << std::endl;

    if(image!=NULL) cvReleaseImage( &image );
    double t1 = vpTime::measureTimeMs();
    std::cout << "== Conversion c interface : " << t1 - t0 << " ms" << std::endl;
#endif

    /* ------------------------------------------------------------------------ */
    /*                  conversion for the new c++ interface                    */
    /* ------------------------------------------------------------------------ */

#if VISP_HAVE_OPENCV_VERSION >= 0x020100
    double t2 = vpTime::measureTimeMs();
    // Convert a cv::Mat to a vpImage<vpRGBa>
    std::cout << "** Convert a cv::Mat to a vpImage<vpRGBa>" << std::endl;
    cv::Mat imageMat;
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");
    std::cout << "   Reading the color image with c++ interface of opencv: " << filename << std::endl;
    imageMat = cv::imread(filename, 1);// force to a three channel color image.
    if(imageMat.data == NULL){
      std::cout << "   Cannot read image: "<< filename << std::endl;
      return -1;
    }
    vpImageConvert::convert(imageMat, Ic);
    filename = vpIoTools::createFilePath(opath, "Klimt_color_cvMat.ppm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ic, filename) ;

    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.pgm");
    /* Read the pgm image */

    std::cout << "   Reading the greyscale image with opencv: " << filename << std::endl;
    imageMat = cv::imread(filename, 0);// forced to grayscale.
    if(imageMat.data == NULL) {
      std::cout << "   Cannot read image: "<< filename << std::endl;
      return (-1);
    }
    vpImageConvert::convert(imageMat, Ic);
    filename = vpIoTools::createFilePath(opath, "Klimt_grey_cvMat.ppm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ic, filename) ;

    // Convert a cv::Mat to a vpImage<unsigned char>
    std::cout << "** Convert a cv::Mat to a vpImage<nsigned char>" << std::endl;
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");

    /* Read the color image */

    std::cout << "   Reading the color image with opencv: " << filename << std::endl;
    imageMat = cv::imread(filename, 1);// force to a three channel color image.
    if(imageMat.data == NULL){
      std::cout << "   Cannot read image: " << filename << std::endl;
      return -1;
    }
    vpImageConvert::convert(imageMat, Ig);
    filename = vpIoTools::createFilePath(opath, "Klimt_color_cvMat.pgm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ig, filename) ;

    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.pgm");

    /* Read the pgm image */

    std::cout  << "   Reading the greyscale image with opencv: " << filename << std::endl;
    imageMat = cv::imread(filename, 0);
    if(imageMat.data == NULL){
      std::cout << "   Cannot read image: "<< filename << std::endl;
      return (-1);
    }
    vpImageConvert::convert(imageMat, Ig);
    filename = vpIoTools::createFilePath(opath, "Klimt_grey_cvMat.pgm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(Ig, filename) ;

    std::cout << "   Convert result in " << filename << std::endl;

    // Convert a vpImage<vpRGBa> to a cv::Mat
    std::cout << "** Convert a vpImage<vpRGBa> to a cv::Mat" << std::endl;
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");

    /* Read the color image */

    // Load a color image from the disk
    std::cout << "   Load " << filename << std::endl;
    vpImageIo::read(Ic, filename) ;
    vpImageConvert::convert(Ic, imageMat);
    filename = vpIoTools::createFilePath(opath, "Klimt_ipl_color_cvMat.ppm");
    /* Save the the current image */
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    if(!cv::imwrite(filename, imageMat)){
      std::cout << "   Cannot write image: " << filename << std::endl;
      return (-1);
    }
    std::cout << "   Convert result in " << filename << std::endl;

    // Convert a vpImage<unsigned char> to a cv::Mat
    std::cout << "** Convert a vpImage<unsigned char> to a cv::Mat" << std::endl;
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.pgm");

    /* Read the grey image */

    // Load a color image from the disk
    std::cout << "   Load " << filename << std::endl;
    vpImageIo::read(Ig, filename);
    vpImageConvert::convert(Ig, imageMat);
    filename = vpIoTools::createFilePath(opath, "Klimt_ipl_grey_cvMat.pgm");
    /* Save the the current image */

    std::cout << "   Resulting image saved in: " << filename << std::endl;
    if(!cv::imwrite(filename, imageMat)){
      std::cout << "   Cannot write image: "<< filename << std::endl;
      return (-1);
    }
    std::cout << "   Convert result in " << filename << std::endl;
    double t3 = vpTime::measureTimeMs();
    std::cout << "== Conversion c++ interface : " << t3 - t2 << " ms" << std::endl;
#endif
#endif

    // Split a vpImage<vpRGBa> to vpImage<unsigned char>
    std::cout << "** Split a vpImage<vpRGBa> to vpImage<unsigned char>" << std::endl;
    filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");

    /* Read the color image */

    // Load a color image from the disk
    std::cout << "   Load " << filename << std::endl;
    vpImageIo::read(Ic, filename) ;
    vpImage<unsigned char> R,G,B,a;
    vpImageConvert::split(Ic, &R,NULL,&B);
    double begintime  = vpTime::measureTimeMs();
    for(int i=0; i<1000;i++){
      vpImageConvert::split(Ic, &R,NULL,&B);
    }
    double endtime = vpTime::measureTimeMs();

    std::cout << "   Time for 1000 split (ms): " << endtime - begintime <<std::endl;

    filename = vpIoTools::createFilePath(opath, "Klimt_RChannel.pgm");
    /* Save the the current image */
    std::cout << "   Save Klimt R channel: " << filename << std::endl;
    vpImageIo::write(R, filename) ;

    filename =  vpIoTools::createFilePath(opath, "Klimt_BChannel.pgm");
    /* Save the the current image */
    std::cout << "   Save Klimt B channel: " << filename << std::endl;
    vpImageIo::write(B, filename) ;

    // Merge 4 vpImage<unsigned char> (RGBa) to vpImage<vpRGBa>
    std::cout << "** Merge 4 vpImage<unsigned char> (RGBa) to vpImage<vpRGBa>" << std::endl;
    vpImageConvert::split(Ic, &R, &G, &B, &a);
    begintime  = vpTime::measureTimeMs();
    vpImage<vpRGBa> I_merge;
    for(int i=0; i<1000; i++){
      vpImageConvert::merge(&R, &G, &B, &a, I_merge);
    }
    endtime = vpTime::measureTimeMs();

    std::cout << "   Time for 1000 merge (ms): "<< endtime - begintime <<std::endl;

    filename =  vpIoTools::createFilePath(opath, "Klimt_merge.ppm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(I_merge, filename) ;

    // Convert a vpImage<vpRGBa> in RGB color space to a vpImage<vpRGBa> in HSV color
    std::cout << "** Convert a vpImage<vpRGBa> in RGB color space to a vpImage<vpRGBa> in HSV color" << std::endl;
    unsigned int size = Ic.getSize();
    unsigned int w = Ic.getWidth(), h = Ic.getHeight();
    unsigned char *hue = new unsigned char[size];
    unsigned char *saturation = new unsigned char[size];
    unsigned char *value = new unsigned char[size];

    vpImageConvert::RGBaToHSV((unsigned char *) Ic.bitmap, hue, saturation, value, size);
    vpImage<unsigned char> I_hue(hue, h, w);
    vpImage<unsigned char> I_saturation(saturation, h, w);
    vpImage<unsigned char> I_value(value, h, w);
    vpImage<vpRGBa> I_HSV;
    vpImageConvert::merge(&I_hue, &I_saturation, &I_value, NULL, I_HSV);

    filename =  vpIoTools::createFilePath(opath, "Klimt_HSV.ppm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(I_HSV, filename);

    //Check the conversion RGBa <==> HSV
    double *hue2 = new double[size];
    double *saturation2 = new double[size];
    double *value2 = new double[size];
    vpImageConvert::RGBaToHSV((unsigned char *) Ic.bitmap, hue2, saturation2, value2, size);

    unsigned char *rgba = new unsigned char[size*4];
    vpImageConvert::HSVToRGBa(hue2, saturation2, value2, rgba, size);

    if(hue2 != NULL) {
      delete[] hue2;
      hue2 = NULL;
    }

    if(saturation2 != NULL) {
      delete[] saturation2;
      saturation2 = NULL;
    }

    if(value2 != NULL) {
      delete[] value2;
      value2 = NULL;
    }

    vpImage<vpRGBa> I_HSV2RGBa((vpRGBa *) rgba, h, w);
    filename =  vpIoTools::createFilePath(opath, "Klimt_HSV2RGBa.ppm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(I_HSV2RGBa, filename);

    for(unsigned int i = 0; i < Ic.getHeight(); i++) {
      for(unsigned int j = 0; j < Ic.getWidth(); j++) {
        if(Ic[i][j].R != I_HSV2RGBa[i][j].R ||
           Ic[i][j].G != I_HSV2RGBa[i][j].G ||
           Ic[i][j].B != I_HSV2RGBa[i][j].B) {
          std::cerr << "Ic[i][j].R=" << static_cast<unsigned>(Ic[i][j].R)
                    << " ; I_HSV2RGBa[i][j].R=" << static_cast<unsigned>(I_HSV2RGBa[i][j].R) << std::endl;
          std::cerr << "Ic[i][j].G=" << static_cast<unsigned>(Ic[i][j].G)
                    << " ; I_HSV2RGBa[i][j].G=" << static_cast<unsigned>(I_HSV2RGBa[i][j].G) << std::endl;
          std::cerr << "Ic[i][j].B=" << static_cast<unsigned>(Ic[i][j].B)
                    << " ; I_HSV2RGBa[i][j].B=" << static_cast<unsigned>(I_HSV2RGBa[i][j].B) << std::endl;
          throw vpException(vpException::fatalError, "Problem with conversion between RGB <==> HSV");
        }
      }
    }

    // Test construction of a vpImage from an array with copyData==true
    std::cout << "** Construction of a vpImage from an array with copyData==true" << std::endl;
    unsigned char *rgba2 = new unsigned char[size*4];
    memset(rgba2, 127, size*4);
    vpImage<vpRGBa> I_copyData((vpRGBa *) rgba2, h, w, true);

    // Delete the array
    delete[] rgba2;

    filename =  vpIoTools::createFilePath(opath, "I_copyData.ppm");
    std::cout << "   Resulting image saved in: " << filename << std::endl;
    vpImageIo::write(I_copyData, filename);

    if(I_copyData.getSize() > 0) {
      I_copyData[0][0].R = 10;
    }


    //Benchmark and test RGBa / RGB / cv::Mat to Grayscale conversion
    {
      std::cout << "** Benchmark and test RGBa / RGB / cv::Mat to Grayscale conversion" << std::endl;
      //RGBa to Grayscale
      vpImage<vpRGBa> I_color;
      filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");
      vpImageIo::read(I_color, filename);

      vpImage<unsigned char> I_gray_sse(I_color.getHeight(), I_color.getWidth());
      vpImage<unsigned char> I_gray_regular(I_color.getHeight(), I_color.getWidth());
      unsigned char value_sse = 0, value_regular = 0;

      double t_sse = vpTime::measureTimeMs();
      for(int iteration = 0; iteration < nbIterations; iteration++) {
        vpImageConvert::convert(I_color, I_gray_sse);
        value_sse += I_gray_sse[0][0];
      }
      t_sse = vpTime::measureTimeMs() - t_sse;

      double t_regular = vpTime::measureTimeMs();
      for(int iteration = 0; iteration < nbIterations; iteration++) {
        computeRegularRGBaToGrayscale((unsigned char *) I_color.bitmap, I_gray_regular.bitmap, I_color.getSize());
        value_regular += I_gray_regular[0][0];
      }
      t_regular = vpTime::measureTimeMs() - t_regular;

      //Compute the error between the SSE and regular version
      double rmse_error = 0.0;
      for(unsigned int i = 0; i < I_color.getHeight(); i++) {
        for(unsigned int j = 0; j < I_color.getWidth(); j++) {
          rmse_error += (I_gray_sse[i][j] - I_gray_regular[i][j]) * (I_gray_sse[i][j] - I_gray_regular[i][j]);
        }
      }

      std::cout << "\n   RGBa to Grayscale" << std::endl;
      std::cout << "   t_regular (" << nbIterations << " iterations)=" << t_regular << " ms"
                << " ; t_sse (" << nbIterations << " iterations)=" << t_sse << " ms" << std::endl;
      std::cout << "   Speed-up=" << (t_regular/t_sse) << "X" << std::endl;
      std::cout << "   RMSE error between SSE and regular version: " << (std::sqrt(rmse_error/I_color.getSize())) << std::endl;

      //To prevent the iteration loop to not be optimized?
      std::cout << "   value_sse=" << static_cast<unsigned>(value_sse)
                << " ; value_regular=" << static_cast<unsigned>(value_regular) << std::endl;

      filename =  vpIoTools::createFilePath(opath, "I_rgba2gray_sse.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_gray_sse, filename);

      filename =  vpIoTools::createFilePath(opath, "I_rgba2gray_regular.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_gray_regular, filename);

      //RGB to Grayscale conversion
      unsigned char *rgb_array = new unsigned char[I_color.getSize() * 3];
      vpImageConvert::RGBaToRGB((unsigned char *) I_color.bitmap, rgb_array, I_color.getSize());

      value_sse = 0;
      value_regular = 0;

      unsigned char *rgb2gray_array_sse = new unsigned char[I_color.getSize()];
      t_sse = vpTime::measureTimeMs();
      for(int iteration = 0; iteration < nbIterations; iteration++) {
        vpImageConvert::RGBToGrey(rgb_array, rgb2gray_array_sse, I_color.getWidth(), I_color.getHeight(), false);
        value_sse += rgb2gray_array_sse[0];
      }
      t_sse = vpTime::measureTimeMs() - t_sse;

      unsigned char *rgb2gray_array_regular = new unsigned char[I_color.getSize()];
      t_regular = vpTime::measureTimeMs();
      for(int iteration = 0; iteration < nbIterations; iteration++) {
        computeRegularRGBToGrayscale(rgb_array, rgb2gray_array_regular, I_color.getSize());
        value_regular += rgb2gray_array_regular[0];
      }
      t_regular = vpTime::measureTimeMs() - t_regular;

      vpImage<unsigned char> I_gray2rgba_sse(rgb2gray_array_sse, I_color.getHeight(), I_color.getWidth(), false);
      vpImage<unsigned char> I_gray2rgba_regular(rgb2gray_array_regular, I_color.getHeight(), I_color.getWidth(), false);

      //Compute the error between the SSE and regular version
      rmse_error = 0.0;
      for(unsigned int i = 0; i < I_color.getHeight(); i++) {
        for(unsigned int j = 0; j < I_color.getWidth(); j++) {
          rmse_error += (I_gray2rgba_sse[i][j] - I_gray2rgba_regular[i][j]) * (I_gray2rgba_sse[i][j] - I_gray2rgba_regular[i][j]);
        }
      }

      std::cout << "\n   RGB to Grayscale" << std::endl;
      std::cout << "   t_regular (" << nbIterations << " iterations)=" << t_regular << " ms"
                << " ; t_sse (" << nbIterations << " iterations)=" << t_sse << " ms" << std::endl;
      std::cout << "   Speed-up=" << (t_regular/t_sse) << "X" << std::endl;
      std::cout << "   RMSE error between SSE and regular version: " << (std::sqrt(rmse_error/I_color.getSize())) << std::endl;

      //To prevent the iteration loop to not be optimized?
      std::cout << "   value_sse=" << static_cast<unsigned>(value_sse)
                << " ; value_regular=" << static_cast<unsigned>(value_regular) << std::endl;

      filename =  vpIoTools::createFilePath(opath, "I_rgb2gray_sse.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_gray2rgba_sse, filename);

      filename =  vpIoTools::createFilePath(opath, "I_rgb2gray_regular.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_gray2rgba_regular, filename);

#if (VISP_HAVE_OPENCV_VERSION >= 0x020101)
      //BGR cv::Mat to Grayscale
      std::cout << "\n   BGR cv::Mat to Grayscale" << std::endl;
      filename = vpIoTools::createFilePath(ipath, "ViSP-images/Klimt/Klimt.ppm");
      cv::Mat colorMat = cv::imread(filename);
      std::cout << "   colorMat=" << colorMat.cols << "x" << colorMat.rows << std::endl;

      vpImage<unsigned char> I_mat2gray_sse, I_mat2gray_regular;
      value_sse = 0;
      value_regular = 0;

      t_sse = vpTime::measureTimeMs();
      for(int iteration = 0; iteration < nbIterations; iteration++) {
        vpImageConvert::convert(colorMat, I_mat2gray_sse, false);
        value_sse += I_mat2gray_sse[0][0];
      }
      t_sse = vpTime::measureTimeMs() - t_sse;

      t_regular = vpTime::measureTimeMs();
      for(int iteration = 0; iteration < nbIterations; iteration++) {
        computeRegularBGRToGrayscale(colorMat, I_mat2gray_regular);
        value_regular += I_mat2gray_sse[0][0];
      }
      t_regular = vpTime::measureTimeMs() - t_regular;

      //Compute the error between the SSE and regular version
      rmse_error = 0.0;
      for(unsigned int i = 0; i < I_color.getHeight(); i++) {
        for(unsigned int j = 0; j < I_color.getWidth(); j++) {
          rmse_error += (I_mat2gray_sse[i][j] - I_mat2gray_regular[i][j]) * (I_mat2gray_sse[i][j] - I_mat2gray_regular[i][j]);
        }
      }

      std::cout << "   t_regular (" << nbIterations << " iterations)=" << t_regular << " ms"
                << " ; t_sse (" << nbIterations << " iterations)=" << t_sse << " ms" << std::endl;
      std::cout << "   Speed-up=" << (t_regular/t_sse) << "X" << std::endl;
      std::cout << "   RMSE error between SSE and regular version: " << (std::sqrt(rmse_error/I_color.getSize())) << std::endl;

      //To prevent the iteration loop to not be optimized?
      std::cout << "   value_sse=" << static_cast<unsigned>(value_sse)
                << " ; value_regular=" << static_cast<unsigned>(value_regular) << std::endl;

      filename =  vpIoTools::createFilePath(opath, "I_mat2gray_sse.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_mat2gray_sse, filename);

      filename =  vpIoTools::createFilePath(opath, "I_mat2gray_regular.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_mat2gray_regular, filename);


      //BGR cv::Mat to Grayscale cv::Mat
      std::cout << "\n   BGR Mat to Grayscale Mat" << std::endl;
      cv::Mat grayscaleMat(colorMat.size(), CV_8U);
      unsigned char value_mat = 0;

      double t_opencv = vpTime::measureTimeMs();
      for(int iteration = 0; iteration < nbIterations; iteration++) {
        cv::cvtColor(colorMat, grayscaleMat, cv::COLOR_BGR2GRAY);
        value_mat += grayscaleMat.ptr<uchar>(0)[0];
      }
      t_opencv = vpTime::measureTimeMs() - t_opencv;

      std::cout << "   t_opencv (" << nbIterations << " iterations)=" << t_opencv << " ms"
                << " ; t_sse (" << nbIterations << " iterations)=" << t_sse << " ms" << std::endl;
      std::cout << "   Speed-up=" << (t_opencv/t_sse) << "X" << std::endl;
      std::cout << "   value_mat=" << static_cast<unsigned>(value_mat) << std::endl;

      vpImage<unsigned char> I_grayscale_mat;
      vpImageConvert::convert(grayscaleMat, I_grayscale_mat);
      filename =  vpIoTools::createFilePath(opath, "grayscaleMat.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_grayscale_mat, filename);


      //Test RGB to Grayscale + Flip
      std::cout << "\n   RGB to Grayscale + Flip" << std::endl;
      unsigned char *rgb2gray_flip_array_sse = new unsigned char[I_color.getSize()];
      vpImageConvert::RGBToGrey(rgb_array, rgb2gray_flip_array_sse, I_color.getWidth(), I_color.getHeight(), true);
      vpImage<unsigned char> I_rgb2gray_flip_sse(rgb2gray_flip_array_sse, I_color.getHeight(), I_color.getWidth());

      filename =  vpIoTools::createFilePath(opath, "I_rgb2gray_flip_sse.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_rgb2gray_flip_sse, filename);


      //Test BGR to Grayscale + Flip
      std::cout << "\n   Conversion BGR to Grayscale + Flip" << std::endl;
      unsigned char *bgr2gray_flip_array_sse = new unsigned char[I_color.getSize()];
      vpImage<unsigned char> I_bgr2gray_flip_sse(bgr2gray_flip_array_sse, I_color.getHeight(), I_color.getWidth());
      vpImageConvert::convert(colorMat, I_bgr2gray_flip_sse, true);

      filename =  vpIoTools::createFilePath(opath, "I_bgr2gray_flip_sse.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_bgr2gray_flip_sse, filename);


      //Test RGB to Grayscale + Flip + Crop
      std::cout << "\n   RGB to Grayscale + Flip + Crop" << std::endl;
      cv::Rect rect_roi(11, 17, 347, 449);
      cv::Mat colorMat_crop = colorMat(rect_roi);
      cv::Mat colorMat_crop_continous = colorMat(rect_roi).clone();
      std::cout << "   colorMat_crop: " << colorMat_crop.cols << "x" << colorMat_crop.rows <<
                   " is continuous? " << colorMat_crop.isContinuous() << std::endl;
      std::cout << "   colorMat_crop_continous: " << colorMat_crop_continous.cols
                << "x" << colorMat_crop_continous.rows << " is continuous? "
                << colorMat_crop_continous.isContinuous() << std::endl;

      vpImage<vpRGBa> I_color_crop( (unsigned int) (rect_roi.height-rect_roi.y), (unsigned int) (rect_roi.width-rect_roi.x) );
      for(unsigned int i = (unsigned int) rect_roi.y; i < (unsigned int) rect_roi.height; i++) {
        for(unsigned int j = (unsigned int) rect_roi.x; j < (unsigned int) rect_roi.width; j++) {
          I_color_crop[(unsigned int) ((int)i-rect_roi.y)][(unsigned int) ((int)j-rect_roi.x)] = I_color[i][j];
        }
      }
      filename =  vpIoTools::createFilePath(opath, "I_color_crop.ppm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_color_crop, filename);

      unsigned char *rgb_array_crop = new unsigned char[I_color_crop.getSize()*3];
      vpImageConvert::RGBaToRGB((unsigned char *) I_color_crop.bitmap, rgb_array_crop, I_color_crop.getSize());

      unsigned char *rgb2gray_flip_crop_array_sse = new unsigned char[I_color_crop.getSize()];
      vpImageConvert::RGBToGrey(rgb_array_crop, rgb2gray_flip_crop_array_sse, I_color_crop.getWidth(),
                                I_color_crop.getHeight(), true);
      vpImage<unsigned char> I_rgb2gray_flip_crop_sse(rgb2gray_flip_crop_array_sse, I_color_crop.getHeight(),
                                                      I_color_crop.getWidth());

      filename =  vpIoTools::createFilePath(opath, "I_rgb2gray_flip_crop_sse.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_rgb2gray_flip_crop_sse, filename);


      //Test BGR to Grayscale + Flip + Crop
      std::cout << "\n   BGR to Grayscale + Flip + Crop" << std::endl;
      vpImage<unsigned char> I_bgr2gray_flip_crop_sse(I_color_crop.getHeight(), I_color_crop.getWidth());
      vpImageConvert::convert(colorMat_crop_continous, I_bgr2gray_flip_crop_sse, true);

      filename =  vpIoTools::createFilePath(opath, "I_bgr2gray_flip_crop_sse.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_bgr2gray_flip_crop_sse, filename);


      //Test BGR to Grayscale + Flip + Crop + No continuous Mat
      std::cout << "\n   BGR to Grayscale + Flip + Crop + No continuous Mat" << std::endl;
      vpImage<unsigned char> I_bgr2gray_flip_crop_no_continuous_sse(I_color_crop.getHeight(),
                                                                    I_color_crop.getWidth());
      vpImageConvert::convert(colorMat_crop, I_bgr2gray_flip_crop_no_continuous_sse, true);

      filename =  vpIoTools::createFilePath(opath, "I_bgr2gray_flip_crop_no_continuous_sse.pgm");
      std::cout << "   Resulting image saved in: " << filename << std::endl;
      vpImageIo::write(I_bgr2gray_flip_crop_no_continuous_sse, filename);
#endif
      delete [] rgb_array;
      std::cout << "Test succeed" << std::endl;
    }

    return 0;
  }
  catch(const vpException &e) {
    std::cout << "Catch an exception: " << e.getMessage() << std::endl;
    return 1;
  }
}