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ImageCorrelation

Header:	AVL.h
Namespace:	avl
Module:	FoundationPro

Computes the correlation of pattern and image.

Syntax

void avl::ImageCorrelation
(
	const avl::Image& inImage,
	const avl::Image& inPatternImage,
	atl::Optional<const avl::Region&> inRoi,
	avl::CorrelationMeasure::Type inCorrelationMeasure,
	float& outCorrelation
)

Parameters

Name	Type	Default	Description
inImage	const Image&		Input image
inPatternImage	const Image&		Pattern to be compared with input image
inRoi	Optional<const Region&>	NIL	Range of pixels to be processed
inCorrelationMeasure	CorrelationMeasure::Type		Measure of correlation
outCorrelation	float&		Value of correlation of pattern and image

Description

The operation computes the correlation between two images using the selected measure.

If the inCorrelationMeasure is set to CrossCorrelation then the resulting outCorrelation is the sum of products of corresponding pixel values of the images.
If the inCorrelationMeasure is set to NormalizedCrossCorrelation then the resulting outCorrelation is the normalized sum of products of corresponding pixel values of the images. This value always lies in closed interval \([-1,1]\), with \(1\) indicating the images ideal correlation.

The operation requires that the images being processed have equal format and dimensions, otherwise an error with appropriate description occurs. To obtain an image of desired dimensions one can use ResizeImage or CropImage filter. To alter the format of an image one can use filters contained in Image Conversions category.

Examples

Normalized cross correlation between the sample images equals 0.919.

Normalized cross correlation between the sample images equals 0.798.

Errors

List of possible exceptions: