cv::NAryMatIterator Class Reference

#include <core.hpp>

Public Member Functions
	NAryMatIterator ()
	the default constructor More...
	NAryMatIterator (const Mat **arrays, uchar **ptrs, int narrays=-1)
	the full constructor taking arbitrary number of n-dim matrices More...
	NAryMatIterator (const Mat **arrays, Mat *planes, int narrays=-1)
	the full constructor taking arbitrary number of n-dim matrices More...
void	init (const Mat **arrays, Mat *planes, uchar **ptrs, int narrays=-1)
	the separate iterator initialization method More...
NAryMatIterator &	operator++ ()
	proceeds to the next plane of every iterated matrix More...
NAryMatIterator	operator++ (int)
	proceeds to the next plane of every iterated matrix (postfix increment operator) More...

Public Attributes
const Mat **	arrays
	the iterated arrays More...
Mat *	planes
	the current planes More...
uchar **	ptrs
	data pointers More...
int	narrays
	the number of arrays More...
size_t	nplanes
	the number of hyper-planes that the iterator steps through More...
size_t	size
	the size of each segment (in elements) More...

Protected Attributes
int	iterdepth
size_t	idx

Detailed Description

n-Dimensional Dense Matrix Iterator Class.

The class cv::NAryMatIterator is used for iterating over one or more n-dimensional dense arrays (cv::Mat's).

The iterator is completely different from cv::Mat_ and cv::SparseMat_ iterators. It iterates through the slices (or planes), not the elements, where "slice" is a continuous part of the arrays.

Here is the example on how the iterator can be used to normalize 3D histogram:

void normalizeColorHist(Mat& hist)
{
#if 1
    // intialize iterator (the style is different from STL).
    // after initialization the iterator will contain
    // the number of slices or planes
    // the iterator will go through
    Mat* arrays[] = { &hist, 0 };
    Mat planes[1];
    NAryMatIterator it(arrays, planes);
    double s = 0;
    // iterate through the matrix. on each iteration
    // it.planes[i] (of type Mat) will be set to the current plane of
    // i-th n-dim matrix passed to the iterator constructor.
    for(int p = 0; p < it.nplanes; p++, ++it)
       s += sum(it.planes[0])[0];
    it = NAryMatIterator(hist);
    s = 1./s;
    for(int p = 0; p < it.nplanes; p++, ++it)
       it.planes[0] *= s;
#elif 1
    // this is a shorter implementation of the above
    // using built-in operations on Mat
    double s = sum(hist)[0];
    hist.convertTo(hist, hist.type(), 1./s, 0);
#else
    // and this is even shorter one
    // (assuming that the histogram elements are non-negative)
    normalize(hist, hist, 1, 0, NORM_L1);
#endif
}

You can iterate through several matrices simultaneously as long as they have the same geometry (dimensionality and all the dimension sizes are the same), which is useful for binary and n-ary operations on such matrices. Just pass those matrices to cv::MatNDIterator. Then, during the iteration it.planes[0], it.planes[1], ... will be the slices of the corresponding matrices

Constructor & Destructor Documentation

NAryMatIterator() [1/3]

cv::NAryMatIterator::NAryMatIterator

(

)

the default constructor

NAryMatIterator() [2/3]

cv::NAryMatIterator::NAryMatIterator	(	const Mat **	arrays,
		uchar **	ptrs,
		int	narrays = -1
	)

the full constructor taking arbitrary number of n-dim matrices

NAryMatIterator() [3/3]

cv::NAryMatIterator::NAryMatIterator	(	const Mat **	arrays,
		Mat *	planes,
		int	narrays = -1
	)

the full constructor taking arbitrary number of n-dim matrices

Member Function Documentation

init()

void cv::NAryMatIterator::init	(	const Mat **	arrays,
		Mat *	planes,
		uchar **	ptrs,
		int	narrays = -1
	)

the separate iterator initialization method

operator++() [1/2]

NAryMatIterator& cv::NAryMatIterator::operator++

(

)

proceeds to the next plane of every iterated matrix

operator++() [2/2]

NAryMatIterator cv::NAryMatIterator::operator++

(

int

)

proceeds to the next plane of every iterated matrix (postfix increment operator)

Member Data Documentation

arrays

const Mat** cv::NAryMatIterator::arrays

the iterated arrays

idx

size_t cv::NAryMatIterator::idx

protected

iterdepth

int cv::NAryMatIterator::iterdepth

protected

narrays

int cv::NAryMatIterator::narrays

the number of arrays

nplanes

size_t cv::NAryMatIterator::nplanes

the number of hyper-planes that the iterator steps through

planes

Mat* cv::NAryMatIterator::planes

the current planes

ptrs

uchar** cv::NAryMatIterator::ptrs

data pointers

size

size_t cv::NAryMatIterator::size

the size of each segment (in elements)

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

• core/core.hpp