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ImagePolarTransform


Header: AVL.h
Namespace: avl
Module: FoundationBasic

Transforms an image to polar or log-polar space.

Syntax

C++
C#
 
void avl::ImagePolarTransform
(
	const avl::Image& inImage,
	const avl::Point2D& inCenter,
	avl::PolarSpaceType::Type inOutputSpaceType,
	avl::PolarInterpolationMethod::Type inInterpolation,
	avl::Image& outImage
)

Parameters

Name Type Default Description
inImage const Image& Input image
inCenter const Point2D& Center of the coordinate system in input image
inOutputSpaceType PolarSpaceType::Type Method of transformation
inInterpolation PolarInterpolationMethod::Type Method of underlying interpolation
outImage Image& Output image

Description

It uses the following transformation:

\[ dst(\rho, \phi) = src(x,y), \]

where

\[ \rho = m \sqrt{x^2 + y^2} , \phi = \arctan(\frac{y}{x}), \]

for linear-polar space, and

\[ \rho = k \log{\sqrt{x^2+y^2} }, \phi = \arctan(\frac{y}{x}), \]

for log-polar space, which emulates the human "foveal vision".

Parameters \(m\) and \(k\) are chosen so that entire source image could fit into output image.

Transformation does not change image dimensions.

Examples

ImagePolarTransform performed on the sample image with inCenter = (150,150), and inOutputSpaceType Polar and LogPolar respectively.

See Also