usRFToPreScan2DConverter.cpp

/****************************************************************************
 *
 * This file is part of the ustk software.
 * Copyright (C) 2016 - 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 ustk with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * 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 ustk@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.
 *
 * Authors:
 * Pedro Patlan
 * Marc Pouliquen
 *
 *****************************************************************************/
 
#include <visp3/ustk_core/usRFToPreScan2DConverter.h>
 
#if defined(USTK_HAVE_FFTW)
 
usRFToPreScan2DConverter::usRFToPreScan2DConverter(int decimationFactor)
  : m_logCompressor(), m_decimationFactor(decimationFactor), m_isInit(false)
{
}
 
usRFToPreScan2DConverter::~usRFToPreScan2DConverter()
{
  if (m_isInit) {
    fftw_free(m_fft_in);
    fftw_free(m_fft_out);
    fftw_free(m_fft_conv);
    fftw_free(m_fft_out_inv);
    fftw_destroy_plan(m_p);
    fftw_destroy_plan(m_pinv);
    delete m_env;
    delete m_comp;
  }
}
 
void usRFToPreScan2DConverter::init(int widthRF, int heigthRF)
{
  if (m_isInit && (m_signalSize != heigthRF || m_scanLineNumber != widthRF)) {
    fftw_free(m_fft_in);
    fftw_free(m_fft_out);
    fftw_free(m_fft_conv);
    fftw_free(m_fft_out_inv);
    fftw_destroy_plan(m_p);
    fftw_destroy_plan(m_pinv);
    delete m_env;
    delete m_comp;
  } else if (m_signalSize == heigthRF && m_scanLineNumber == heigthRF)
    return;
 
  // for FFT
  m_fft_in = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * heigthRF);
  m_fft_out = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * heigthRF);
  m_fft_conv = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * heigthRF);
  m_fft_out_inv = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * heigthRF);
 
  // log compression
  m_env = new double[heigthRF * widthRF];
  m_comp = new unsigned char[heigthRF * widthRF];
 
  m_signalSize = heigthRF;
  m_scanLineNumber = widthRF;
 
  m_p = fftw_plan_dft_1d(m_signalSize, m_fft_in, m_fft_out, FFTW_FORWARD, FFTW_ESTIMATE);
  m_pinv = fftw_plan_dft_1d(m_signalSize, m_fft_out, m_fft_out_inv, FFTW_BACKWARD, FFTW_ESTIMATE);
 
  m_isInit = true;
}
 
void usRFToPreScan2DConverter::enveloppeDetection(const short int *s, double *out)
{
  // const clock_t begin_time = clock();
  int N = m_signalSize;
 
  // Put signal data s into in
  for (int i = 0; i < N; i++) {
    m_fft_in[i][0] = (double)s[i];
    m_fft_in[i][1] = 0.0;
  }
 
  // Obtain the FFT
  fftw_execute(m_p);
 
  for (int i = 0; i < N; i++) {
 
    if (i < N / 2)
      m_fft_out[i][1] = -m_fft_out[i][1];
    else if (i == N / 2) {
      m_fft_out[i][0] = 0;
      m_fft_out[i][1] = 0;
    } else if (i > N / 2)
      m_fft_out[i][0] = -m_fft_out[i][0];
    if (i == 0) {
      m_fft_out[i][0] = 0;
      m_fft_out[i][1] = 0;
    }
 
    double z = m_fft_out[i][1];
    m_fft_out[i][1] = m_fft_out[i][0];
    m_fft_out[i][0] = z;
  }
 
  // FFT Inverse
 
  // Obtain the IFFT
  fftw_execute(m_pinv);
  // Put the iFFT output in sa
  double Ndouble = (double)N;
  for (int i = 0; i < N; i++) {
    out[i] = (unsigned char)sqrt(abs(std::complex<double>(m_fft_in[i][0], -m_fft_out_inv[i][0] / Ndouble)));
  }
}
 
void usRFToPreScan2DConverter::convert(const usImageRF2D<short int> &rfImage,
                                       usImagePreScan2D<unsigned char> &preScanImage)
{
 
  if (!m_isInit || ((int)rfImage.getWidth()) != m_scanLineNumber || ((int)rfImage.getHeight()) != m_signalSize) {
    init(rfImage.getWidth(), rfImage.getHeight());
  }
  preScanImage.resize(rfImage.getHeight() / m_decimationFactor, rfImage.getWidth());
 
  // First we copy the transducer settings
  preScanImage.setImagePreScanSettings(rfImage);
 
  unsigned int w = rfImage.getWidth();
  unsigned int h = rfImage.getHeight();
 
  unsigned int frameSize = w * h;
 
  // prepare signals corresponding to each scanline or column (the bitmap is storing row after row)
  std::vector<short *> rfSignals;
  for (unsigned int j = 0; j < w; j++) {
    short *s = new short[h];
    for (unsigned int i = 0; i < h; i++) {
      s[i] = rfImage(i, j);
    }
    rfSignals.push_back(s);
  }
 
  // Run envelope detector
  for (unsigned int i = 0; i < w; ++i) {
    enveloppeDetection(rfImage.getSignal(i), m_env + i * h);
  }
 
  // Log-compress
  m_logCompressor.run(m_comp, m_env, frameSize);
 
  // find min & max values
  double min = 1e8;
  double max = -1e8;
  for (unsigned int i = 0; i < frameSize; ++i) {
    if (m_comp[i] < min)
      min = m_comp[i];
    if (m_comp[i] > max)
      max = m_comp[i];
  }
  // max-min computation
  double maxMinDiff = max - min;
 
  // Decimate and normalize
  unsigned int k = 0;
  for (unsigned int i = 0; i < h; i += m_decimationFactor) {
    for (unsigned int j = 0; j < w; ++j) {
      unsigned int vcol = (unsigned int)(((m_comp[i + h * j] - min) / maxMinDiff) * 255);
      preScanImage[k][j] = (vcol > 255) ? 255 : vcol;
    }
    k++;
    if (k == preScanImage.getHeight()) // prevent overflow for k at last iteration (index given to operator[] on vpImage
                                       // goes from 0 to N-1)
      return;
  }
}
 
int usRFToPreScan2DConverter::getDecimationFactor() { return m_decimationFactor; }
 
void usRFToPreScan2DConverter::setDecimationFactor(int decimationFactor) { m_decimationFactor = decimationFactor; }
 
#endif