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/*=========================================================================
Program: GDCM (Grassroots DICOM). A DICOM library
Copyright (c) 2006-2011 Mathieu Malaterre
All rights reserved.
See Copyright.txt or http://gdcm.sourceforge.net/Copyright.html for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
#ifndef GDCMIMAGECHANGEPHOTOMETRICINTERPRETATION_H
#define GDCMIMAGECHANGEPHOTOMETRICINTERPRETATION_H
#include "gdcmImageToImageFilter.h"
#include "gdcmPhotometricInterpretation.h"
#include <limits>
namespace gdcm
{
class DataElement;
/**
* \brief ImageChangePhotometricInterpretation class
* \details Class to change the Photometric Interpretation of an input DICOM
*/
class GDCM_EXPORT ImageChangePhotometricInterpretation : public ImageToImageFilter
{
public:
ImageChangePhotometricInterpretation():PI() {}
~ImageChangePhotometricInterpretation() = default;
/// Set/Get requested PhotometricInterpretation
void SetPhotometricInterpretation(PhotometricInterpretation const &pi) { PI = pi; }
const PhotometricInterpretation &GetPhotometricInterpretation() const { return PI; }
/// Change
bool Change();
/// colorspace conversion (based on CCIR Recommendation 601-2)
/// -> T.871
template <typename T>
static void RGB2YBR(T ybr[3], const T rgb[3], unsigned short storedbits = 8);
template <typename T>
static void YBR2RGB(T rgb[3], const T ybr[3], unsigned short storedbits = 8);
protected:
bool ChangeMonochrome();
bool ChangeYBR2RGB();
bool ChangeRGB2YBR();
private:
PhotometricInterpretation PI;
};
template <typename T>
static inline int Round(T x)
{
return (int)(x+0.5);
}
template <typename T>
static inline T Clamp(int v)
{
assert( std::numeric_limits<T>::min() == 0 );
return v < 0 ? 0 : (v > std::numeric_limits<T>::max() ? std::numeric_limits<T>::max() : v);
}
template <typename T>
void ImageChangePhotometricInterpretation::RGB2YBR(T ybr[3], const T rgb[3], unsigned short storedbits)
{
// Implementation details, since the equations from:
// http://dicom.nema.org/medical/dicom/current/output/chtml/part03/sect_C.7.6.3.html#sect_C.7.6.3.1.2
// are rounded to the 4th decimal precision, prefer the exact equation from the original document at:
// CCIR Recommendation 601-2, also found in T.871 (Section ยง7, page 4)
const double R = rgb[0];
const double G = rgb[1];
const double B = rgb[2];
assert( storedbits <= sizeof(T) * 8 );
const int halffullscale = 1 << (storedbits - 1);
const int Y = Round( 0.299 * R + 0.587 * G + 0.114 * B );
const int CB = Round((-0.299 * R - 0.587 * G + 0.886 * B)/1.772 + halffullscale);
const int CR = Round(( 0.701 * R - 0.587 * G - 0.114 * B)/1.402 + halffullscale);
ybr[0] = Clamp<T>(Y );
ybr[1] = Clamp<T>(CB);
ybr[2] = Clamp<T>(CR);
}
template <typename T>
void ImageChangePhotometricInterpretation::YBR2RGB(T rgb[3], const T ybr[3], unsigned short storedbits)
{
const double Y = ybr[0];
const double Cb = ybr[1];
const double Cr = ybr[2];
assert( storedbits <= sizeof(T) * 8 );
const int halffullscale = 1 << (storedbits - 1);
const int R = Round(Y + 1.402 * (Cr-halffullscale) );
const int G = Round(Y -( 0.114 * 1.772 * (Cb-halffullscale) + 0.299 * 1.402 * (Cr-halffullscale))/0.587);
const int B = Round(Y + 1.772 * (Cb-halffullscale) );
rgb[0] = Clamp<T>(R);
rgb[1] = Clamp<T>(G);
rgb[2] = Clamp<T>(B);
}
} // end namespace gdcm
#endif //GDCMIMAGECHANGEPHOTOMETRICINTERPRETATION_H
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