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Header: AVL.h
Namespace: avl
Module: FoundationPro

Computes an image of correlation between a pattern and the input image at each possible location.

Applications: This filter is used internally by the Gray-based Template Matching.


void avl::ImageCorrelationImage
	const avl::Image& inImage,
	const avl::Image& inPatternImage,
	atl::Optional<const avl::Region&> inRoi,
	atl::Optional<const avl::Region&> inPatternRoi,
	avl::CorrelationMeasure::Type inCorrelationMeasure,
	avl::Image& outImage


Name Type Default Description
Input value inImage const Image& Input image
Input value inPatternImage const Image& Pattern to be compared with input image
Input value inRoi Optional<const Region&> NIL Range of pixels to be processed
Input value inPatternRoi Optional<const Region&> NIL Range of pixels in the pattern to be processed
Input value inCorrelationMeasure CorrelationMeasure::Type Measure of correlation
Output value outImage Image& Output image


The operation computes the correlation between inImage and inPatternImage. The inPatternImage is aligned at each location of the inImage and the similarity between the inPatternImage and the corresponding part of the inImage is estimated using the inCorrelationMeasure as in ImageCorrelation filter. The result is stored in the pixel of the outImage that corresponds to the location at which the center of inPatternImage was aligned to the inImage.


A sample inImage.

A sample inPatternImage.

The resulting outImage multiplied by 255.

The locations in the inImage corresponding to the brightest points of the outImage.

Hardware Acceleration

This operation supports automatic parallelization for multicore and multiprocessor systems.

This operation supports processing on OpenCL compatible device (when inRoi=NIL, inPatternRoi=NIL and pixel type is uint8).


List of possible exceptions:

Error type Description
DomainError Not supported correlation measure in ImageCorrelationImage.

See Also

  • LocateMultipleObjects_NCC – Finds all occurrences of a predefined template on an image by analysing the normalized correlation between pixel values.