Utility helper class for faster and more convenient access to single channel image data. More...

#include <Channel.h>

Public Types
typedef T *	iterator
	typedef for a normal iterator (just a pointer) More...

typedef const T *	const_iterator
	const iterator type (just a const pointer) More...

typedef ImgIterator< T >	roi_iterator
	type definition for ROI iterator More...

typedef const ImgIterator< T >	const_roi_iterator
	type definition for a const ROI iterator More...

Public Member Functions
	Channel ()
	Empty constructor (create an invalid Channel object) More...

	Channel (const Channel &other)
	Copy an image channel (this could be exploited to violate const concept) More...

Channel< T > &	operator= (Channel< T > &other)
	assignmet operator More...

const Channel< T > &	operator= (const Channel< T > &other) const
	assign operator (also for const channels) More...

T &	operator() (int x, int y)
	main working function: returns a reference to the pixel at position (x,y) More...

T &	operator() (const utils::Point &p)
	convenience function for point-based index access More...

const T &	operator() (const utils::Point &p) const
	convenience function for point-based index access (const) More...

const T &	operator() (int x, int y) const
	main working function: returns const a reference to the pixel at position (x,y) More...

T &	operator[] (int idx)
	working function for linear pixel array access ( not const version) More...

const T &	operator[] (int idx) const
	working function for linear pixel array access (const version) More...

template<class Vec2D >
T	operator() (const Vec2D &p) const
	index operator with linear interpolation More...

iterator	begin ()
	returns the image iterator (equal to getData(channel)) More...

const_iterator	begin () const
	returns the image iterator (equal to getData(channel)) (const) More...

iterator	end ()
	returns the image end-iterator (equal to getData(channel)+getDim()) More...

const_iterator	end () const
	returns the image end-iterator (const) More...

roi_iterator	beginROI ()
	returns the iterator for an images ROI More...

const_roi_iterator	beginROI () const
	returns the iterator for an images ROI (const) More...

roi_iterator	endROI ()
	returns the end-iterator for an images ROI More...

const_roi_iterator	endROI () const
	returns the end-iterator for an images ROI (const) More...

bool	isNull () const

int	getWidth () const
	returns the wrapped images width More...

int	getHeight () const
	returns the wrapped images height More...

const utils::Size &	getSize () const
	retusn the wrapped images size More...

int	getDim () const
	returns the wrapped images dim = width*height More...

const utils::Rect &	getROI () const
	returns the channel ROI More...

utils::Point	getROIOffset () const
	returns the channel ROI offset More...

utils::Size	getROISize () const
	returns the channel ROI size More...

int	getROIWidth () const
	returns the channel ROI width More...

int	getROIHeight () const
	returns the channel ROI height More...

int	getROIXOffset () const
	returns the channel ROI X-Offset More...

int	getROIYOffset () const
	returns the channel ROI Y-Offset More...

void	redefineROI (const utils::Rect &newROI) const
	Sets a new ROI to this image channel (this does not affect the underlying images ROI) More...

void	deepCopy (Channel< T > &other) const
	deeply copies the channel data (no roi support here) More...

template<class OtherT >
void	convert (Channel< OtherT > &other) const
	deeply converts the channel data (no roi support here) More...

Private Member Functions
	Channel (const T *data, const utils::Size &size, const utils::Rect &roi)
	private constructor More...

	Channel (T *data, const utils::Size &size, const utils::Rect &roi)

Private Attributes
T *	m_data

utils::Size	m_size

utils::Rect	m_roi

Friends
class	Img< T >
	mades Img<T> a friend to allow it construction of ImgChannels More...

Detailed Description

template<class T>
class icl::core::Channel< T >

Utility helper class for faster and more convenient access to single channel image data.

Yet, the (x,x,c)-operator of the Img<T> class is slow, because of hight computational overhead due to the necessity of a channel lookup The (x,y,c)-operator needs first to lookup for the channel c in the channel array of the image, before it can address a pixels value by dereferencing the shared pointers wrapped data pointer. In many cases, The user works on images with a fixed channel count (mostly 1 or 3), and needs a simple (x,y)-data access operator, which translates an (x,y) pixel address into the raw data pointer address dataPointer[x+width*y].
The Channel class was designed to facilitate this procedure. To avoid the arise of an The following code example shows how to replace the Imgs (x,y,c)-operator by using the Channel template class:

inline void copy_image(Img32f &A,Img32f &B){
  for(int x=0;x<1000;x++){                     // default version for an image copy
    for(int y=0;y<1000;y++){                   // each pixel is addressed by the
      A(x,y,0)=B(x,y,0);                       // (x,y,c)-operator (image size is fixed)
    }
  }
}
inline void copy_image(Img32f &A,Img32f &B){
  Channel32f a = A.extractChannel(0);         // new faster version (about 6.5-times
  Channel32f b = B.extractChannel(0);         // faster, than the above function
  for(int x=0;x<1000;x++){                    // pixels are addressed by the
    for(int y=0;y<1000;y++){                  // ImgChannel objects
      a(x,y)=b(x,y);
    }
  }
}

The lower function is about 6.5 times faster than the upper one!

When working on multi channel images with a fixed channel count, the advantage of using the ImgChannel class becomes even greater:

inline void copy_3_channels(ImgQ &A,ImgQ &B){
  for(int x=0;x<1000;x++){
    for(int y=0;y<1000;y++){
      A(x,y,0)=B(x,y,0);
      A(x,y,1)=B(x,y,1);
      A(x,y,2)=B(x,y,2);
    }
  }
}
inline void copy_3_channels(ImgQ &A,ImgQ &B){
  Channel32f a[3]; A.extractChannels(a);
  Channel32f b[3]; B.extractChannels(b);
    for(int x=0;x<1000;x++){
      for(int y=0;y<1000;y++){            // more than one channel can be
        a[0](x,y)=b[0](x,y);              // stored in a fixed size array of
        a[1](x,y)=b[1](x,y);              // Channel32f structs; this allows
        a[2](x,y)=b[2](x,y);              // direct access to the channel data pointer
      }
    }
  }
}

In The above example, the lower version of the copy function is even 7 times as fast as the upper version. At last, we want to examine the speed advantage for dynamic channel count and image size. The corresponding code is illustrated in the following code example:

inline void dynamic_image_copy(ImgQ &A,ImgQ &B){
  for(int x=0;x<A.getWidth();x++){
    for(int y=0;y<A.getHeight();y++){
      for(int c=0;c<A.getChannels();c++){         // here, a dynamic channel loop
        A(x,y,c)=B(x,y,c);                        // is implemented
      }
    }
  }
}
inline void dynamic_image_copy_2(ImgQ &A,ImgQ &B){
  Channel32f *a = new Channel32f[A.getChannels()];     // pre allocate buffer for
  Channel32f *b = new Channel32f[A.getChannels()];     // the channel Objects
  A.extractChannels(a);                                // assign the channel objects with
  B.extractChannels(b);                                // the channel data of the images
  for(int x=0;x<A.getWidth();x++){
    for(int y=0;y<A.getHeight();y++){
      for(int c=0;c<A.getChannels();c++){                    // again use a dynamic channel loop,
        a[c](x,y)=b[c](x,y);                                 // but make use of the channel struct
      }
    }
  }
  delete [] a;                                              // release the channel structs
  delete [] b;
}

In this example, the lower function is only 3 times faster, than the above one. Here, the advantage is not as large as in the above examples, but an acceleration factor of 3 should not be neglected.
The Channel<T> template class is typedef'd for all current Img<T> classes Channel8u, Channel16s, Channel32s, Channel32f, Channel64f.

Member Typedef Documentation

◆ const_iterator

template<class T>

typedef const T* icl::core::Channel< T >::const_iterator

const iterator type (just a const pointer)

◆ const_roi_iterator

template<class T>

typedef const ImgIterator<T> icl::core::Channel< T >::const_roi_iterator

type definition for a const ROI iterator

◆ iterator

template<class T>

typedef T* icl::core::Channel< T >::iterator

typedef for a normal iterator (just a pointer)

◆ roi_iterator

template<class T>

typedef ImgIterator<T> icl::core::Channel< T >::roi_iterator

type definition for ROI iterator

Constructor & Destructor Documentation

◆ Channel() [1/4]

template<class T>

icl::core::Channel< T >::Channel ( )

inline

Empty constructor (create an invalid Channel object)

This constructor is necessary for the creation of uninitialized dynamic size arrays of Channel objects

◆ Channel() [2/4]

template<class T>

icl::core::Channel< T >::Channel ( const Channel< T > & other )

inline

Copy an image channel (this could be exploited to violate const concept)

◆ Channel() [3/4]

template<class T>

icl::core::Channel< T >::Channel	(	const T *	data,
		const utils::Size &	size,
		const utils::Rect &	roi
	)

inlineprivate

private constructor

Parameters

data	data pointer (image) wich's channel should be wrapped
size	size of the data
roi	roi of the data (image)

◆ Channel() [4/4]

template<class T>

icl::core::Channel< T >::Channel	(	T *	data,
		const utils::Size &	size,
		const utils::Rect &	roi
	)

inlineprivate

Member Function Documentation

◆ begin() [1/2]

template<class T>

iterator icl::core::Channel< T >::begin ( )

inline

returns the image iterator (equal to getData(channel))

◆ begin() [2/2]

template<class T>

const_iterator icl::core::Channel< T >::begin ( ) const

inline

returns the image iterator (equal to getData(channel)) (const)

◆ beginROI() [1/2]

template<class T>

roi_iterator icl::core::Channel< T >::beginROI ( )

inline

returns the iterator for an images ROI

◆ beginROI() [2/2]

template<class T>

const_roi_iterator icl::core::Channel< T >::beginROI ( ) const

inline

returns the iterator for an images ROI (const)

◆ convert()

template<class T>

template<class OtherT >

void icl::core::Channel< T >::convert ( Channel< OtherT > & other ) const

inline

deeply converts the channel data (no roi support here)

◆ deepCopy()

template<class T>

void icl::core::Channel< T >::deepCopy ( Channel< T > & other ) const

inline

deeply copies the channel data (no roi support here)

◆ end() [1/2]

template<class T>

iterator icl::core::Channel< T >::end ( )

inline

returns the image end-iterator (equal to getData(channel)+getDim())

◆ end() [2/2]

template<class T>

const_iterator icl::core::Channel< T >::end ( ) const

inline

returns the image end-iterator (const)

◆ endROI() [1/2]

template<class T>

roi_iterator icl::core::Channel< T >::endROI ( )

inline

returns the end-iterator for an images ROI

the returned iterator must not be incremented or decremented!

◆ endROI() [2/2]

template<class T>

const_roi_iterator icl::core::Channel< T >::endROI ( ) const

inline

returns the end-iterator for an images ROI (const)

◆ getDim()

template<class T>

int icl::core::Channel< T >::getDim ( ) const

inline

returns the wrapped images dim = width*height

Returns: wrapped images pixel count

◆ getHeight()

template<class T>

int icl::core::Channel< T >::getHeight ( ) const

inline

returns the wrapped images height

Returns: wrapped images height

◆ getROI()

template<class T>

const utils::Rect& icl::core::Channel< T >::getROI ( ) const

inline

returns the channel ROI

◆ getROIHeight()

template<class T>

int icl::core::Channel< T >::getROIHeight ( ) const

inline

returns the channel ROI height

◆ getROIOffset()

template<class T>

utils::Point icl::core::Channel< T >::getROIOffset ( ) const

inline

returns the channel ROI offset

◆ getROISize()

template<class T>

utils::Size icl::core::Channel< T >::getROISize ( ) const

inline

returns the channel ROI size

◆ getROIWidth()

template<class T>

int icl::core::Channel< T >::getROIWidth ( ) const

inline

returns the channel ROI width

◆ getROIXOffset()

template<class T>

int icl::core::Channel< T >::getROIXOffset ( ) const

inline

returns the channel ROI X-Offset

◆ getROIYOffset()

template<class T>

int icl::core::Channel< T >::getROIYOffset ( ) const

inline

returns the channel ROI Y-Offset

◆ getSize()

template<class T>

const utils::Size& icl::core::Channel< T >::getSize ( ) const

inline

retusn the wrapped images size

◆ getWidth()

template<class T>

int icl::core::Channel< T >::getWidth ( ) const

inline

returns the wrapped images width

Returns: wrapped images width

◆ isNull()

template<class T>

bool icl::core::Channel< T >::isNull ( ) const

inline

◆ operator()() [1/5]

template<class T>

T& icl::core::Channel< T >::operator()	(	int	x,
		int	y
	)

inline

main working function: returns a reference to the pixel at position (x,y)

The data address is calculated by x+ImageWidth*y. Note: no checks are performed to ensure, that the position is valid!

Parameters

x	x-Position
y	y-Position

Returns: reference to the Pixel at (x,y)

◆ operator()() [2/5]

template<class T>

T& icl::core::Channel< T >::operator() ( const utils::Point & p )

inline

convenience function for point-based index access

calls operator()(p.x,p.y)

◆ operator()() [3/5]

template<class T>

const T& icl::core::Channel< T >::operator() ( const utils::Point & p ) const

inline

convenience function for point-based index access (const)

calls operator()(p.x,p.y) const

◆ operator()() [4/5]

template<class T>

const T& icl::core::Channel< T >::operator()	(	int	x,
		int	y
	)		const

inline

main working function: returns const a reference to the pixel at position (x,y)

The data address is calculated by x+ImageWidth*y. Note: no checks are performed to ensure, that the position is valid!

Parameters

x	x-Position
y	y-Position

Returns: reference to the Pixel at (x,y)

◆ operator()() [5/5]

template<class T>

template<class Vec2D >

T icl::core::Channel< T >::operator() ( const Vec2D & p ) const

inline

index operator with linear interpolation

The given source type must provide an index operator (so does e.g. icl::Point, icl::Point32f, icl::FixedMatrix and icl::FixedVector). There is no internal check so take care yourself that the given position is within the image rectangle

◆ operator=() [1/2]

template<class T>

Channel<T>& icl::core::Channel< T >::operator= ( Channel< T > & other )

inline

assignmet operator

◆ operator=() [2/2]

template<class T>

const Channel<T>& icl::core::Channel< T >::operator= ( const Channel< T > & other ) const

inline

assign operator (also for const channels)

assign operator is const, as we use to const-ness to deny changes on the underlying image, but not on the Channel struct itself. Hence all class data is mutable

◆ operator[]() [1/2]

template<class T>

T& icl::core::Channel< T >::operator[] ( int idx )

inline

working function for linear pixel array access ( not const version)

Parameters

idx	pixel array index

Returns: reference to the pixel at linear pixel offfset idx

◆ operator[]() [2/2]

template<class T>

const T& icl::core::Channel< T >::operator[] ( int idx ) const

inline

working function for linear pixel array access (const version)

Parameters

idx	pixel array index

Returns: reference to the pixel at linear pixel offfset idx

◆ redefineROI()

template<class T>

void icl::core::Channel< T >::redefineROI ( const utils::Rect & newROI ) const

inline

Sets a new ROI to this image channel (this does not affect the underlying images ROI)

Parameters

newROI new channel roi

Friends And Related Function Documentation

◆ Img< T >

template<class T>

friend class Img< T >

friend

mades Img<T> a friend to allow it construction of ImgChannels

Member Data Documentation

◆ m_data

template<class T>

T* icl::core::Channel< T >::m_data

mutableprivate

◆ m_roi

template<class T>

utils::Rect icl::core::Channel< T >::m_roi

mutableprivate

◆ m_size

template<class T>

utils::Size icl::core::Channel< T >::m_size

mutableprivate

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

/Users/alneuman/vm/icl/ICLCore/src/ICLCore/Channel.h

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Friends

Detailed Description

template<class T> class icl::core::Channel< T >

Member Typedef Documentation

◆ const_iterator

◆ const_roi_iterator

◆ iterator

◆ roi_iterator

Constructor & Destructor Documentation

◆ Channel() [1/4]

◆ Channel() [2/4]

◆ Channel() [3/4]

◆ Channel() [4/4]

Member Function Documentation

◆ begin() [1/2]

◆ begin() [2/2]

◆ beginROI() [1/2]

◆ beginROI() [2/2]

◆ convert()

◆ deepCopy()

◆ end() [1/2]

◆ end() [2/2]

◆ endROI() [1/2]

◆ endROI() [2/2]

◆ getDim()

◆ getHeight()

◆ getROI()

◆ getROIHeight()

◆ getROIOffset()

◆ getROISize()

◆ getROIWidth()

◆ getROIXOffset()

◆ getROIYOffset()

◆ getSize()

◆ getWidth()

◆ isNull()

◆ operator()() [1/5]

◆ operator()() [2/5]

◆ operator()() [3/5]

◆ operator()() [4/5]

◆ operator()() [5/5]

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ operator[]() [1/2]

◆ operator[]() [2/2]

◆ redefineROI()

Friends And Related Function Documentation

◆ Img< T >

Member Data Documentation

◆ m_data

◆ m_roi

◆ m_size

template<class T>
class icl::core::Channel< T >