You are here: Start » Function Reference » Image » Image Metrics » ColorDistanceImage

ColorDistanceImage

Header:	FIL.h
Namespace:	fil
Module:	FoundationPro

Compares each pixel with the specified color using chromatic and non-chromatic information.

Applications: Color analysis insensitive to changes of illumination.

Syntax

void fil::ColorDistanceImage
(
	const fil::Image& inImage,
	ftl::Optional<const fil::Region&> inRoi,
	const fil::Pixel& inRgbColor,
	float inChromaAmount,
	fil::Image& outValueImage
)

Parameters

Name	Type	Range	Default	Description
inImage	const Image&			Unsigned color image used in comparison
inRoi	Optional<const Region&>		NIL	Range of pixels to be processed
inRgbColor	const Pixel&			Color to compare the image to
inChromaAmount	float	0.0 - 1.0	0.7f	Proportion of chromatic information in distance computation
outValueImage	Image&			Unsigned image of distances

Requirements

For input inImage only pixel formats are supported: 1⨯uint8, 2⨯uint8, 3⨯uint8, 4⨯uint8.

Read more about pixel formats in Image documentation.

Description

The operation computes the distance between each pixel of inImage and a specified color, presenting result as a monochromatic image. Input image should be in RGB color space.

The distance between pixels is computed using two measures:

Value distance - the difference between average channel values
Chromatic distance - euclidean distance between pixels normalized to the same value level

The resulting distance is computed as a weighted average of these two values, parameter inChromaAmount ( 0.0 - 1.0 ) being the weight of the chromatic distance, and 1 - inChromaAmount being the weight of the value distance.

Examples

ColorDistanceImage run with inRgbColor = , inChromaAmount = 0.8

Hardware Acceleration

This operation supports automatic parallelization for multicore and multiprocessor systems.

Errors

List of possible exceptions:

Error type	Description
DomainError	Invalid image Depth in ColorDistanceImage.
DomainError	Not supported inImage pixel format in ColorDistanceImage. Supported formats: 1xUInt8, 2xUInt8, 3xUInt8, 4xUInt8.
RuntimeError	Each pixel component of inRgbColor must be nonnegative in ColorDistanceImage.