/********************************************************************
**                Image Component Library (ICL)                    **
**                                                                 **
** Copyright (C) 2006-2010 CITEC, University of Bielefeld          **
**                         Neuroinformatics Group                  **
** Website: www.iclcv.org and                                      **
**          http://opensource.cit-ec.de/projects/icl               **
**                                                                 **
** File   : include/ICLFilter/GradientImage.h                      **
** Module : ICLFilter                                              **
** Authors: Christof Elbrechter                                    **
**                                                                 **
**                                                                 **
** Commercial License                                              **
** ICL can be used commercially, please refer to our website       **
** www.iclcv.org for more details.                                 **
**                                                                 **
** GNU General Public License Usage                                **
** Alternatively, this file may be used under the terms of the     **
** GNU General Public License version 3.0 as published by the      **
** Free Software Foundation and appearing in the file LICENSE.GPL  **
** included in the packaging of this file.  Please review the      **
** following information to ensure the GNU General Public License  **
** version 3.0 requirements will be met:                           **
** http://www.gnu.org/copyleft/gpl.html.                           **
**                                                                 **
** 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.                                          **
**                                                                 **
*********************************************************************/

#ifndef ICL_GRADIENT_IMAGE_H
#define ICL_GRADIENT_IMAGE_H

#include <ICLCore/ImgBase.h>
#include <ICLCore/Img.h>

namespace icl{
  
  /// Class for calculation of gradient image information
  /** The GradientImage class provides functionalities for
      the calculation of the following gradient image information:
      - X-Gradient (using 3x3 Sobel-X Convolution Kenrnel)
      - Y-Gradient (using 3x3 Sobel-Y Convolution Kenrnel)
      - Gradient Intensity (internally accelerated using a LUT)
        \f$ I=\sqrt(gx^2+gy^2) \f$ 
      - Gradient Angle (also accelerated using a LUT)
        \f$ I=atan2(gy,gx) \f$
      
      For best performance, the input image is restricted to be
      of type Img8u. The update function will firstly calculate
      X- and Y-Gradient information using a ConvolutionOp object.
      X- and Y-Gradient image have range [0,255] now (result of 
      Sobel-Filter is internally scaled to the range of the
      used datatype icl8u. Further calculation of gradient intensity
      and gradient angle depends on the given calculation mode
      flag.      
  */
  class GradientImage{
    public:
    
    /// flags to indicate which gradient information should be calculated
    enum calculationMode{
      calculateXYOnly=0,    ///< only calculate X- and Y-Gradient 
      calculateIntensity=1, ///< X/Y-Gradient and intensity map
      calculateAngle=2,     ///< X/Y-Gradient and angle map
      calculateAll=3        ///< X/Y-Gradient, intensity- and angle map
    };
    
    /// Empty constructor
    GradientImage(){}
    
    /// Main function calculates new gradient image information
    void update(const ImgBase *src, calculationMode mode=calculateAll); 
    
    /// return current X-Gradient image
    const Img16s &getGradXImage() const{ return m_oX; }

    /// return current Y-Gradient image
    const Img16s &getGradYImage() const{ return m_oY; }

    /// return current Gradient-Intensity image
    const Img32f &getGradIntensityImage() const { return m_oI; }

    /// return current Gradient-Angle image
    const Img32f &getGradAngleImage() const { return m_oA; }

    /// internally normalizes all images to range [0,255]
    void normalize();
    private:
    Img16s m_oBuf;
    Img16s m_oX,m_oY;
    Img32f m_oI,m_oA;
  };
}

#endif