reference

`labkit.image.localContrast`

Enhance local value-channel contrast with a mean-filter mask.

Syntax

imageOut = labkit.image.localContrast(imageIn, amountPct, radiusPx)

Description

Converts imageIn to clamped RGB double and operates on the HSV value channel. A square local mean with width 2*radius+1 forms the low-frequency reference. The difference between the value channel and that mean is multiplied by 1.5*amountPct/100 and added back before clipping.

Hue and saturation are preserved by the adjustment. At image boundaries, the local mean uses only available pixels. This is a lightweight local contrast operation, not adaptive histogram equalization.

Inputs

imageIn: Numeric or logical grayscale, RGB, or multichannel image.
amountPct: Numeric scalar effect strength in percent. Negative values are treated as 0.
radiusPx: Numeric scalar neighborhood radius in pixels. The value is rounded and limited to at least 1.

Outputs

imageOut: M-by-N-by-3 double image with values in [0,1].

Failure Behavior

Unsupported image classes or channel shapes propagate errors from im2double or ensureRgb. amountPct and radiusPx must be numeric scalars; incompatible values raise the originating conversion or indexing error.

Example

imageIn = repmat(linspace(0.2, 0.8, 20), 10, 1);
imageOut = labkit.image.localContrast(imageIn, 40, 3);

labkit.image.meanFilter2 — Apply normalized 2-D mean filtering with edge correction.
labkit.image.sharpen — Apply generic unsharp-mask sharpening.
labkit.image.adjustBrightnessContrast — Apply simple brightness and contrast adjustment.
labkit.image.adjustHueSaturation — Apply HSV hue and saturation adjustment.
labkit.image.assertSupportedPaths — Throw when any path has an unsupported image extension.
labkit.image.displayName — Return a short image-file display name.
labkit.image.ensureRgb — Return image data with exactly three color channels.
labkit.image.fileDialogFilter — Return a file-chooser-compatible image filter.

Source

This page is generated from the MATLAB help text in +labkit/+image/localContrast.m.

labkit.image.localContrast