/********************************************************************
**                Image Component Library (ICL)                    **
**                                                                 **
** Copyright (C) 2006-2013 CITEC, University of Bielefeld          **
**                         Neuroinformatics Group                  **
** Website: www.iclcv.org and                                      **
**          http://opensource.cit-ec.de/projects/icl               **
**                                                                 **
** File   : ICLFilter/src/ICLFilter/WienerOp.h                     **
** Module : ICLFilter                                              **
** Authors: Christof Elbrechter, Robert Haschke, Andre Justus      **
**                                                                 **
**                                                                 **
** GNU LESSER GENERAL PUBLIC LICENSE                               **
** This file may be used under the terms of the GNU Lesser General **
** Public License version 3.0 as published by the                  **
**                                                                 **
** Free Software Foundation and appearing in the file LICENSE.LGPL **
** included in the packaging of this file.  Please review the      **
** following information to ensure the license requirements will   **
** be met: http://www.gnu.org/licenses/lgpl-3.0.txt                **
**                                                                 **
** The development of this software was supported by the           **
** Excellence Cluster EXC 277 Cognitive Interaction Technology.    **
** The Excellence Cluster EXC 277 is a grant of the Deutsche       **
** Forschungsgemeinschaft (DFG) in the context of the German       **
** Excellence Initiative.                                          **
**                                                                 **
********************************************************************/

#pragma once

#include <ICLFilter/NeighborhoodOp.h>
#include <vector>

namespace icl {
  namespace filter{
    /// Class for Wiener Filter \ingroup UNARY \ingroup NBH
     /** Wiener filters are commonly used in image processing applications to
         remove additive noise from degraded images, to restore a blurred image.
         
         The following operation is performed on each pixel:
         \f[
         R(x,y,c) = \mu_m(x,y,c) + \frac{\sigma_m^2(x,y,c)-\nu^2}{\sigma^2} * (S(x,y,c) - \mu_m(x,y,c))
         \f]
         
         where: 
         - \f$R(x,y,c)\f$ is the result image at position (x,y) and channel c
         - \f$\mu_m(x,y,c)\f$ is the mean of the image in region m (mask) centered at (x,y), channel c
         - \f$\sigma^2_m(x,y,c)\f$ is the variance of the image in region m (mask) centered at (x,y), channel c
         - \f$\sigma^2 \f$ is the image variance
         - \f$S(x,y,c)\f$ is the source image at position (x,y) and channel c
     */
    class WienerOp : public NeighborhoodOp {
     public:
  
      /// Constructor that creates a wiener filter object, with specified mask size
      /** @param maskSize of odd width and height
          Even width or height is increased to next higher odd value.
          @param noise nois factor
      **/
      WienerOp (const utils::Size &maskSize, icl32f noise=0): NeighborhoodOp(maskSize),m_fNoise(noise){}
  
      /// Filters an image using the Wiener algorithm.
      /** @param poSrc Source image
          @param ppoDst Destination image
      **/
      ICLFilter_API void apply (const core::ImgBase *poSrc, core::ImgBase **ppoDst);
  
      /// Import unaryOps apply function without destination image
      using NeighborhoodOp::apply;
  
      /// returns the current noise factor
      /** @return current noise factor **/
      icl32f getNoise() const { return m_fNoise; }
      
      /// sets up a new noise factor
      /** @ param noise new noise factor **/
      void setNoise(icl32f noise) { m_fNoise = noise; }
      
      private:
      /// internal buffer for applying the wiener operation
      std::vector<icl8u> m_vecBuffer;
      
      /// internal storage for the current noise factor
      icl32f m_fNoise;
    };
  } // namespace filter
} // namespace icl