Start » Filter Reference » Image » Image Enhancement » EqualizeImageHistogram

EqualizeImageHistogram

Basic

Module: FoundationLite

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

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

See Also

  • ImageHistogram – Computes the histogram of the image pixel values.