vpImageMorphology.h

/*
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2025 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:
 * Morphology tools.
 */

 
#ifndef VP_IMAGE_MORPHOLOGY_H
#define VP_IMAGE_MORPHOLOGY_H
 
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpImage.h>
#include <visp3/core/vpImageException.h>
#include <visp3/core/vpMatrix.h>
 
#include <fstream>
#include <iostream>
#include <math.h>
#include <string.h>
 
#if defined(__clang__)
// Mute warning : '\tparam' command used in a comment that is not attached to a template declaration [-Wdocumentation]
#  pragma clang diagnostic push
#  pragma clang diagnostic ignored "-Wexit-time-destructors"
#endif
 
BEGIN_VISP_NAMESPACE
class VISP_EXPORT vpImageMorphology
{
public:
  typedef enum
  {
    CONNEXITY_4, 
    CONNEXITY_8  
  } vpConnexityType;
 
public:
  template <class Type>
  static void erosion(vpImage<Type> &I, Type value, Type value_out, vpConnexityType connexity = CONNEXITY_4);
 
  template <class Type>
  static void dilatation(vpImage<Type> &I, Type value, Type value_out, vpConnexityType connexity = CONNEXITY_4);
 
  template <typename T>
  static void erosion(vpImage<T> &I, const vpConnexityType &connexity = CONNEXITY_4);
 
  template <typename T>
  static void dilatation(vpImage<T> &I, const vpConnexityType &connexity = CONNEXITY_4);
 
  template <typename T>
  static void erosion(vpImage<T> &I, const int &size);
 
  template <typename T>
  static void dilatation(vpImage<T> &I, const int &size);
 
#if defined(VISP_BUILD_DEPRECATED_FUNCTIONS)

  VP_DEPRECATED static void erosion(vpImage<unsigned char> &I, const vpConnexityType &connexity = CONNEXITY_4)
  {
    vpImageMorphology::erosion<unsigned char>(I, connexity);
  }

  VP_DEPRECATED static void dilatation(vpImage<unsigned char> &I, const vpConnexityType &connexity = CONNEXITY_4)
  {
    vpImageMorphology::dilatation<unsigned char>(I, connexity);
  }

#endif
 
private:
  template <typename T>
  class vpPixelOperation
  {
  public:
    vpPixelOperation() { }
 
#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
    virtual ~vpPixelOperation() = default;
#endif
 
    virtual T operator()(const T &, const T &) = 0;
  };
 
  template <typename T>
  class vpPixelOperationMax : public vpPixelOperation<T>
  {
  public:
    vpPixelOperationMax() { }
 
    virtual T operator()(const T &a, const T &b) VP_OVERRIDE
    {
      return std::max<T>(a, b);
    }
  };
 
  template <typename T>
  class vpPixelOperationMin : public vpPixelOperation<T>
  {
  public:
    vpPixelOperationMin() { }
 
    T operator()(const T &a, const T &b) VP_OVERRIDE
    {
      return std::min<T>(a, b);
    }
  };

  template <typename T>
  static void imageOperation(vpImage<T> &I, const T &null_value, vpPixelOperation<T> *operation, const vpConnexityType &connexity = CONNEXITY_4);

  template <typename T>
  static void imageOperation(vpImage<T> &I, vpPixelOperation<T> *operation, const int &size = 3);
 
};

template <class Type>
void vpImageMorphology::erosion(vpImage<Type> &I, Type value, Type value_out, vpConnexityType connexity)
{
  if (I.getSize() == 0) {
    std::cerr << "Input image is empty!" << std::endl;
    return;
  }
 
  vpImage<Type> J(I.getHeight() + 2, I.getWidth() + 2);
  // Copy I to J and add border
  unsigned int j_height = J.getHeight();
  unsigned int j_width = J.getWidth();
  for (unsigned int i = 0; i < j_height; ++i) {
    if ((i == 0) || (i == (j_height - 1))) {
      for (unsigned int j = 0; j < j_width; ++j) {
        J[i][j] = value;
      }
    }
    else {
      J[i][0] = value;
      memcpy(J[i] + 1, I[i - 1], sizeof(unsigned char) * I.getWidth());
      J[i][J.getWidth() - 1] = value;
    }
  }
 
  if (connexity == CONNEXITY_4) {
    unsigned int i_height = I.getHeight();
    unsigned int i_width = I.getWidth();
    for (unsigned int i = 0; i < i_height; ++i) {
      for (unsigned int j = 0; j < i_width; ++j) {
        if (J[i + 1][j + 1] == value) {
          // Consider 4 neighbors
          if ((J[i][j + 1] == value_out) ||     // Top
            (J[i + 2][j + 1] == value_out) || // Bottom
            (J[i + 1][j] == value_out) ||     // Left
            (J[i + 1][j + 2] == value_out)) { // Right
            I[i][j] = value_out;
          }
        }
      }
    }
  }
  else {
    unsigned int i_height = I.getHeight();
    unsigned int i_width = I.getWidth();
    for (unsigned int i = 0; i < i_height; ++i) {
      for (unsigned int j = 0; j < i_width; ++j) {
        if (J[i + 1][j + 1] == value) {
          // Consider 8 neighbors
          bool cond4firstneighbors = (J[i][j] == value_out) || (J[i][j + 1] == value_out) ||
            (J[i][j + 2] == value_out) || (J[i + 1][j] == value_out);
          bool cond4secondneighbors = (J[i + 1][j + 2] == value_out) || (J[i + 2][j] == value_out) ||
            (J[i + 2][j + 1] == value_out) || (J[i + 2][j + 2] == value_out);
          if (cond4firstneighbors || cond4secondneighbors) {
            I[i][j] = value_out;
          }
        }
      }
    }
  }
}

template <class Type>
void vpImageMorphology::dilatation(vpImage<Type> &I, Type value, Type value_out, vpConnexityType connexity)
{
  if (I.getSize() == 0) {
    std::cerr << "Input image is empty!" << std::endl;
    return;
  }
 
  vpImage<Type> J(I.getHeight() + 2, I.getWidth() + 2);
  // Copy I to J and add border
  unsigned int j_height = J.getHeight();
  unsigned int j_width = J.getWidth();
  for (unsigned int i = 0; i < j_height; ++i) {
    if ((i == 0) || (i == (j_height - 1))) {
      for (unsigned int j = 0; j < j_width; ++j) {
        J[i][j] = value_out;
      }
    }
    else {
      J[i][0] = value_out;
      memcpy(J[i] + 1, I[i - 1], sizeof(unsigned char) * I.getWidth());
      J[i][J.getWidth() - 1] = value_out;
    }
  }
 
  if (connexity == CONNEXITY_4) {
    unsigned int i_height = I.getHeight();
    unsigned int i_width = I.getWidth();
    for (unsigned int i = 0; i < i_height; ++i) {
      for (unsigned int j = 0; j < i_width; ++j) {
        if (J[i + 1][j + 1] == value_out) {
          // Consider 4 neighbors
          if ((J[i][j + 1] == value) ||     // Top
            (J[i + 2][j + 1] == value) || // Bottom
            (J[i + 1][j] == value) ||     // Left
            (J[i + 1][j + 2] == value)) { // Right
            I[i][j] = value;
          }
        }
      }
    }
  }
  else {
    unsigned int i_height = I.getHeight();
    unsigned int i_width = I.getWidth();
    for (unsigned int i = 0; i < i_height; ++i) {
      for (unsigned int j = 0; j < i_width; ++j) {
        if (J[i + 1][j + 1] == value_out) {
          // Consider 8 neighbors
          bool cond4firstneighbors = (J[i][j] == value) || (J[i][j + 1] == value) || (J[i][j + 2] == value) || (J[i + 1][j] == value);
          bool cond4secondneighbors = (J[i + 1][j + 2] == value) || (J[i + 2][j] == value) || (J[i + 2][j + 1] == value) ||
            (J[i + 2][j + 2] == value);
          if (cond4firstneighbors || cond4secondneighbors) {
            I[i][j] = value;
          }
        }
      }
    }
  }
}
 
template<typename T>
void vpImageMorphology::imageOperation(vpImage<T> &I, const T &null_value, vpPixelOperation<T> *operation, const vpConnexityType &connexity)
{
  const int width_in = static_cast<int>(I.getWidth());
  const int height_in = static_cast<int>(I.getHeight());
  const unsigned int width_dilat = I.getWidth() + 2;
  const unsigned int height_dilat = I.getHeight() + 2;
  vpImage<T> J(height_dilat, width_dilat, null_value);
 
  // Copy I to J and add border
  J.insert(I, vpImagePoint(1, 1));
 
  if (connexity == vpImageMorphology::CONNEXITY_4) {
    const int nbOffset = 5;
    int offset_x[nbOffset] = { 0, -1, 0, 1, 0 };
    int offset_y[nbOffset] = { -1,  0, 0, 0, 1 };
 
    for (int i = 0; i < height_in; ++i) {
      for (int j = 0; j < width_in; ++j) {
        T value = null_value;
        for (int k = 0; k < nbOffset; ++k) {
          value = (*operation)(value, J[i + 1 + offset_y[k]][j + 1 + offset_x[k]]);
        }
 
        I[i][j] = value;
      }
    }
  }
  else {
    const int nbOffset = 9;
    int offset_x[nbOffset] = { -1, 0, 1,-1, 0, 1,-1, 0, 1 };
    int offset_y[nbOffset] = { -1,-1,-1, 0, 0, 0, 1, 1, 1 };
 
    for (int i = 0; i < height_in; ++i) {
      for (int j = 0; j < width_in; ++j) {
        T value = null_value;
        for (int k = 0; k < nbOffset; ++k) {
          value = (*operation)(value, J[i + 1 + offset_y[k]][j + 1 + offset_x[k]]);
        }
 
        I[i][j] = value;
      }
    }
  }
}

template <typename T>
void vpImageMorphology::erosion(vpImage<T> &I, const vpConnexityType &connexity)
{
  vpPixelOperationMin<T> operation;
  vpImageMorphology::imageOperation(I, std::numeric_limits<T>::max(), &operation, connexity);
}

template <typename T>
void vpImageMorphology::dilatation(vpImage<T> &I, const vpConnexityType &connexity)
{
  vpPixelOperationMax<T> operation;
  vpImageMorphology::imageOperation(I, std::numeric_limits<T>::min(), &operation, connexity);
}
 
template<typename T>
void vpImageMorphology::imageOperation(vpImage<T> &I, vpPixelOperation<T> *operation, const int &size)
{
  if ((size % 2) != 1) {
    throw(vpException(vpException::badValue, "Dilatation/erosion kernel must be odd."));
  }
 
  const int width_in = I.getWidth();
  const int height_in = I.getHeight();
  int halfKernelSize = size / 2;
  vpImage<T> J = I;
 
  for (int r = 0; r < height_in; ++r) {
    // Computing the rows we can explore without going outside the limits of the image
    int r_iterator_start = -halfKernelSize, r_iterator_stop = halfKernelSize + 1;
    if ((r - halfKernelSize) < 0) {
      r_iterator_start = -r;
    }
    else if ((r + halfKernelSize) >= height_in) {
      r_iterator_stop = height_in - r;
    }
    for (int c = 0; c < width_in; ++c) {
      T value = I[r][c];
      // Computing the columns we can explore without going outside the limits of the image
      int c_iterator_start = -halfKernelSize, c_iterator_stop = halfKernelSize + 1;
      if ((c - halfKernelSize) < 0) {
        c_iterator_start = -c;
      }
      else if ((c + halfKernelSize) >= width_in) {
        c_iterator_stop = width_in - c;
      }
      for (int r_iterator = r_iterator_start; r_iterator < r_iterator_stop; ++r_iterator) {
        for (int c_iterator = c_iterator_start; c_iterator < c_iterator_stop; ++c_iterator) {
          value = (*operation)(value, J[r + r_iterator][c + c_iterator]);
        }
      }
      I[r][c] = value;
    }
  }
}

template <typename T>
void vpImageMorphology::erosion(vpImage<T> &I, const int &size)
{
  vpPixelOperationMin<T> operation;
  vpImageMorphology::imageOperation(I, &operation, size);
}

template<typename T>
void vpImageMorphology::dilatation(vpImage<T> &I, const int &size)
{
  vpPixelOperationMax<T> operation;
  vpImageMorphology::imageOperation(I, &operation, size);
}
END_VISP_NAMESPACE
 
#if defined(__clang__)
#  pragma clang diagnostic pop
#endif
 
#endif