Structural Analysis and Shape Descriptors

Enumerations
enum	cv::cuda::MomentsOrder {   cv::cuda::FIRST_ORDER_MOMENTS = 1,   cv::cuda::SECOND_ORDER_MOMENTS = 2,   cv::cuda::THIRD_ORDER_MOMENTS = 3 }
	Order of image moments. More...

Functions
Moments	cv::cuda::moments (InputArray src, const bool binaryImage=false, const MomentsOrder order=MomentsOrder::THIRD_ORDER_MOMENTS, const int momentsType=CV_64F)
	Calculates all of the moments up to the 3rd order of a rasterized shape. More...
int	cv::cuda::numMoments (const MomentsOrder order)
	Returns the number of image moments less than or equal to the largest image moments order. More...
void	cv::cuda::spatialMoments (InputArray src, OutputArray moments, const bool binaryImage=false, const MomentsOrder order=MomentsOrder::THIRD_ORDER_MOMENTS, const int momentsType=CV_64F, Stream &stream=Stream::Null())
	Calculates all of the spatial moments up to the 3rd order of a rasterized shape. More...

Detailed Description

Enumeration Type Documentation

MomentsOrder

enum cv::cuda::MomentsOrder

#include <opencv2/cudaimgproc.hpp>

Order of image moments.

Parameters

FIRST_ORDER_MOMENTS	First order moments
SECOND_ORDER_MOMENTS	Second order moments.
THIRD_ORDER_MOMENTS	Third order moments.

Enumerator
FIRST_ORDER_MOMENTS
SECOND_ORDER_MOMENTS
THIRD_ORDER_MOMENTS

Function Documentation

moments()

Moments cv::cuda::moments	(	InputArray	src,
		const bool	binaryImage = false,
		const MomentsOrder	order = MomentsOrder::THIRD_ORDER_MOMENTS,
		const int	momentsType = CV_64F
	)

#include <opencv2/cudaimgproc.hpp>

Calculates all of the moments up to the 3rd order of a rasterized shape.

The function computes moments, up to the 3rd order, of a rasterized shape. The results are returned in the structure cv::Moments.

Parameters

src	Raster image (single-channel 2D array).
binaryImage	If it is true, all non-zero image pixels are treated as 1's.
order	Order of largest moments to calculate with lower order moments requiring less computation.
momentsType	Precision to use when calculating moments. Available types are CV_32F and CV_64F with the performance of CV_32F an order of magnitude greater than CV_64F. If the image is small the accuracy from CV_32F can be equal or very close to CV_64F.

Note

For maximum performance use the asynchronous version cuda::spatialMoments() as this version interally allocates and deallocates both GpuMat and HostMem to respectively perform the calculation on the device and download the result to the host. The costly HostMem allocation cannot be avoided however the GpuMat device allocation can be by using BufferPool, e.g.

setBufferPoolUsage(true);
setBufferPoolConfig(getDevice(), numMoments(order) * ((momentsType == CV_64F) ? sizeof(double) : sizeof(float)), 1);

see the CUDA_TEST_P(Moments, Accuracy) test inside opencv_contrib_source_code/modules/cudaimgproc/test/test_moments.cpp for an example.

Returns

cv::Moments.

See also

cuda::spatialMoments

numMoments()

int cv::cuda::numMoments

(

const MomentsOrder

order

)

#include <opencv2/cudaimgproc.hpp>

Returns the number of image moments less than or equal to the largest image moments order.

Parameters

order

Order of largest moments to calculate with lower order moments requiring less computation.

Returns

number of image moments.

See also

cuda::moments, cuda::spatialMoments, cuda::MomentsOrder

spatialMoments()

void cv::cuda::spatialMoments	(	InputArray	src,
		OutputArray	moments,
		const bool	binaryImage = false,
		const MomentsOrder	order = MomentsOrder::THIRD_ORDER_MOMENTS,
		const int	momentsType = CV_64F,
		Stream &	stream = Stream::Null()
	)

#include <opencv2/cudaimgproc.hpp>

Calculates all of the spatial moments up to the 3rd order of a rasterized shape.

Asynchronous version of cuda::moments() which only calculates the spatial (not centralized or normalized) moments, up to the 3rd order, of a rasterized shape. Each moment is returned as a column entry in the 1D moments array.

Parameters

	src	Raster image (single-channel 2D array).
[out]	moments	1D array with each column entry containing a spatial image moment.
	binaryImage	If it is true, all non-zero image pixels are treated as 1's.
	order	Order of largest moments to calculate with lower order moments requiring less computation.
	momentsType	Precision to use when calculating moments. Available types are CV_32F and CV_64F with the performance of CV_32F an order of magnitude greater than CV_64F. If the image is small the accuracy from CV_32F can be equal or very close to CV_64F.
	stream	Stream for the asynchronous version.

Note

For maximum performance pre-allocate a 1D GpuMat for moments of the correct type and size large enough to store the all the image moments of up to the desired order. e.g. With order === MomentsOrder::SECOND_ORDER_MOMENTS and momentsType == CV_32F moments can be allocated as

GpuMat momentsDevice(1,numMoments(MomentsOrder::SECOND_ORDER_MOMENTS),CV_32F)

The central and normalized moments can easily be calculated on the host by downloading the moments array and using the cv::Moments constructor. e.g.

HostMem momentsHostMem(1, numMoments(MomentsOrder::SECOND_ORDER_MOMENTS), CV_32F);
momentsDevice.download(momentsHostMem, stream);
stream.waitForCompletion();
Mat momentsMat = momentsHostMem.createMatHeader();
cv::Moments cvMoments(momentsMat.at<float>(0), momentsMat.at<float>(1), momentsMat.at<float>(2), momentsMat.at<float>(3), momentsMat.at<float>(4), momentsMat.at<float>(5), momentsMat.at<float>(6), momentsMat.at<float>(7), momentsMat.at<float>(8), momentsMat.at<float>(9));

see the CUDA_TEST_P(Moments, Async) test inside opencv_contrib_source_code/modules/cudaimgproc/test/test_moments.cpp for an example.

Returns

cv::Moments.

See also

cuda::moments