gdcm::Rescaler Class Reference

Rescale class. More...

#include <gdcmRescaler.h>

Public Member Functions
	Rescaler ()
	~Rescaler ()=default
PixelFormat::ScalarType	ComputeInterceptSlopePixelType ()
PixelFormat	ComputePixelTypeFromMinMax ()
double	GetIntercept () const
double	GetSlope () const
bool	InverseRescale (char *out, const char *in, size_t n)
	Inverse transform.
bool	Rescale (char *out, const char *in, size_t n)
	Direct transform.
void	SetIntercept (double i)
	Set Intercept: used for both direct&inverse transformation.
void	SetMinMaxForPixelType (double min, double max)
void	SetPixelFormat (PixelFormat const &pf)
	Set Pixel Format of input data.
void	SetSlope (double s)
	Set Slope: user for both direct&inverse transformation.
void	SetTargetPixelType (PixelFormat const &targetst)
void	SetUseTargetPixelType (bool b)
	Override default behavior of Rescale.

Protected Member Functions
template<typename TIn >
void	InverseRescaleFunctionIntoBestFit (char *out, const TIn *in, size_t n)
template<typename TIn >
void	RescaleFunctionIntoBestFit (char *out, const TIn *in, size_t n)

Detailed Description

Rescale class.

This class is meant to apply the linear transform of Stored Pixel Value to Real World Value. This is mostly found in CT or PET dataset, where the value are stored using one type, but need to be converted to another scale using a linear transform. There are basically two cases: In CT: the linear transform is generally integer based. E.g. the Stored Pixel Type is unsigned short 12bits, but to get Hounsfield unit, one need to apply the linear transform:

So the best scalar to store the Real World Value will be 16 bits signed type.

In PET: the linear transform is generally floating point based. Since the dynamic range can be quite high, the Rescale Slope / Rescale Intercept can be changing throughout the Series. So it is important to read all linear transform and deduce the best Pixel Type only at the end (when all the images to be read have been parsed).

Warning

Internally any time a floating point value is found either in the Rescale Slope or the Rescale Intercept it is assumed that the best matching output pixel type is FLOAT64 (in previous implementation it was FLOAT32). Because VR:DS is closer to a 64bits floating point type FLOAT64 is thus a best matching pixel type for the floating point transformation.

Example: Let say input is FLOAT64, and we want UINT16 as output, we would do:

Rescaler ir;
ir.SetIntercept( 0 );
ir.SetSlope( 5.6789 );
ir.SetPixelFormat( FLOAT64 );
ir.SetMinMaxForPixelType( ((PixelFormat)UINT16).GetMin(), ((PixelFormat)UINT16).GetMax() );
ir.InverseRescale(output,input,numberofbytes );

Note

handle floating point transformation back and forth to integer properly (no loss)

See also

Unpacker12Bits

Examples

RescaleImage.cs.

Constructor & Destructor Documentation

Rescaler()

gdcm::Rescaler::Rescaler ( )

inline

~Rescaler()

gdcm::Rescaler::~Rescaler ( )

default

Member Function Documentation

ComputeInterceptSlopePixelType()

PixelFormat::ScalarType gdcm::Rescaler::ComputeInterceptSlopePixelType

(

)

Compute the Pixel Format of the output data Used for direct transformation

Examples

RescaleImage.cs.

ComputePixelTypeFromMinMax()

PixelFormat gdcm::Rescaler::ComputePixelTypeFromMinMax

(

)

Compute the Pixel Format of the output data Used for inverse transformation

GetIntercept()

double gdcm::Rescaler::GetIntercept ( ) const

inline

GetSlope()

double gdcm::Rescaler::GetSlope ( ) const

inline

InverseRescale()

bool gdcm::Rescaler::InverseRescale	(	char *	out,
		const char *	in,
		size_t	n
	)

Inverse transform.

InverseRescaleFunctionIntoBestFit()

template<typename TIn >

void gdcm::Rescaler::InverseRescaleFunctionIntoBestFit ( char *  out, const TIn *  in, size_t  n  )

protected

Rescale()

bool gdcm::Rescaler::Rescale	(	char *	out,
		const char *	in,
		size_t	n
	)

Direct transform.

Examples

RescaleImage.cs.

RescaleFunctionIntoBestFit()

template<typename TIn >

void gdcm::Rescaler::RescaleFunctionIntoBestFit ( char *  out, const TIn *  in, size_t  n  )

protected

SetIntercept()

void gdcm::Rescaler::SetIntercept ( double  i )

inline

Set Intercept: used for both direct&inverse transformation.

Examples

RescaleImage.cs.

SetMinMaxForPixelType()

void gdcm::Rescaler::SetMinMaxForPixelType	(	double	min,
		double	max
	)

Set target interval for output data. A best match will be computed (if possible) Used for inverse transformation

SetPixelFormat()

void gdcm::Rescaler::SetPixelFormat ( PixelFormat const &  pf )

inline

Set Pixel Format of input data.

Examples

RescaleImage.cs.

SetSlope()

void gdcm::Rescaler::SetSlope ( double  s )

inline

Set Slope: user for both direct&inverse transformation.

Examples

RescaleImage.cs.

SetTargetPixelType()

void gdcm::Rescaler::SetTargetPixelType

(

PixelFormat const &

targetst

)

By default (when UseTargetPixelType is false), a best matching Target Pixel Type is computed. However user can override this auto selection by switching UseTargetPixelType:true and also specifying the specific Target Pixel Type

SetUseTargetPixelType()

void gdcm::Rescaler::SetUseTargetPixelType

(

bool

b

)

Override default behavior of Rescale.

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The documentation for this class was generated from the following file:

• gdcmRescaler.h