ImageMoment

Header:	AVL.h
Namespace:	avl

Computes the selected moment of an image in regular and normalized (divided by sum of pixel values) variant.

Syntax

void avl::ImageMoment
(
	const avl::Image& inImage,
	atl::Optional<const avl::Region&> inRoi,
	avl::ImageMomentType::Type inMomentType,
	bool inCentral,
	float& outMoment,
	atl::Optional<float&> outNormMoment = atl::NIL
)

Parameters

Name	Type	Default	Description
inImage	const Image&		Input image
inRoi	Optional<const Region&>	NIL	Range of pixels to be processed
inMomentType	ImageMomentType::Type
inCentral	bool
outMoment	float&
outNormMoment	Optional<float&>	NIL

Optional Outputs

The computation of following outputs can be switched off by passing value atl::NIL to these parameters: outNormMoment.

Description

The operation computes the mathematical features of an image called moments. Those are sums computed as follows:

\[ \begin{aligned} Moment_{0,0}(Image,Roi) &= \sum_{p \in Roi} Image(p_x,p_y) \cdot 1 \\ Moment_{0,1}(Image,Roi) &= \sum_{p \in Roi} Image(p_x,p_y) \cdot p_y \\ Moment_{1,0}(Image,Roi) &= \sum_{p \in Roi} Image(p_x,p_y) \cdot p_x \\ Moment_{0,2}(Image,Roi) &= \sum_{p \in Roi} Image(p_x,p_y) \cdot p_y^2 \\ Moment_{1,1}(Image,Roi) &= \sum_{p \in Roi} Image(p_x,p_y) \cdot p_x p_y \\ Moment_{2,0}(Image,Roi) &= \sum_{p \in Roi} Image(p_x,p_y) \cdot p_x^2 \end{aligned} \]

The summing is conducted over all pixels in inRoi region, while \( p_x \) and \( p_y \) denote, accordingly, x and y coordinate of a pixel.

When inCentral parameter is set, the image is shifted before computations, so that its mass center is at location (0,0).

Hardware Acceleration

This operation supports automatic parallelization for multicore and multiprocessor systems.

Errors

List of possible exceptions:

Error type	Description
DomainError	Black image on input in ImageMoment.
DomainError	Empty region on input in ImageMoment.
DomainError	Region exceeds an input image in ImageMoment.