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Contrast Adjustment

Contrast adjustment, histogram equalization, decorrelation stretching


imadjust Adjust image intensity values or colormap
imcontrast Adjust Contrast tool
imsharpen Sharpen image using unsharp masking
locallapfilt Fast Local Laplacian Filtering of images
localcontrast Edge-aware local contrast manipulation of images
localtonemap Render HDR image for viewing while enhancing local contrast
histeq Enhance contrast using histogram equalization
adapthisteq Contrast-limited adaptive histogram equalization (CLAHE)
imhistmatch Adjust histogram of image to match N-bin histogram of reference image
decorrstretch Apply decorrelation stretch to multichannel image
stretchlim Find limits to contrast stretch image
intlut Convert integer values using lookup table
imnoise Add noise to image

Examples and How To

Adjust Image Contrast In Image Viewer App

Using the Image Viewer's Adjust Contrast tool

Adjust Image Intensity Values to Specified Range

This example shows how to increase the contrast in a low-contrast grayscale image by remapping the data values to fill the entire available intensity range [0, 255].

Histogram Equalization

The process of adjusting intensity values can be done automatically using histogram equalization.

Adaptive Histogram Equalization

As an alternative to using histeq, you can perform contrast-limited adaptive histogram equalization (CLAHE) using the adapthisteq function.

Enhance Color Separation Using Decorrelation Stretching

Decorrelation stretching enhances the color separation of an image with significant band-to-band correlation.


Contrast Adjustment

Image enhancement techniques are used to improve an image, where "improve" is sometimes defined objectively (e.g., increase the signal-to-noise ratio), and sometimes subjectively (e.g., make certain features easier to see by modifying the colors or intensities).

Understanding Contrast Adjustment

An image lacks contrast when there are no sharp differences between black and white.

Gamma Correction

imadjust maps low to bottom, and high to top.

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