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EqualizeImageHistogram

Module:	FoundationLite

Maps image pixels to new values to achieve uniform distribution of intensities in the range (0, 255).

Name	Type	Range	Description
inImage	Image		Input image
inRoi	Region *		Range of pixels to be processed
inSaturateBrightestFraction	Real	0.0 - 1.0	Fraction of the brightest pixels skipped during normalization
inSaturateDarkestFraction	Real	0.0 - 1.0	Fraction of the darkest pixels skipped during normalization
outImage	Image		Output image

Requirements

For input inImage only pixel formats are supported: 1⨯uint8.

Read more about pixel formats in Image documentation.

Description

The filter applies non-linear mapping to image pixel values so that pixel intensities of the resulting image are evenly distributed in range from 0 to 255.

The operation computes the cumulative histogram \(C\) of inImage and the image size \(N\). Then the result is computed as follows:

\[ \begin{aligned} outImage[i,j] &= C[ inImage[i,j] ] \times \frac{255}{N} \end{aligned} \]

Examples

EqualizeImageHistogram run on example image.

Hardware Acceleration

This operation supports automatic parallelization for multicore and multiprocessor systems.

Errors

This filter can throw an exception to report error. Read how to deal with errors in Error Handling.

List of possible exceptions:

Error type	Description
DomainError	Region exceeds an input image in EqualizeImageHistogram.
DomainError	The sum of inSaturateBrightestFraction and inSaturateDarkestFraction can't be greater than 1 in EqualizeImageHistogram.
DomainError	Not supported inImage pixel format in EqualizeImageHistogram. Supported formats: 1xUInt8.

Complexity Level

This filter is available on Basic Complexity Level.