gray2ind (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

Convert an intensity image to an indexed image

Syntax

[X,map] = gray2ind(I,n)
[X,map] = gray2ind(BW,n)

Description

gray2ind scales, then rounds, an intensity image to produce an equivalent indexed image.

[X,map] = gray2ind(I,n) converts the intensity image I to an indexed image X with colormap gray(n). If n is omitted, it defaults to 64.

[X,map] = gray2ind(BW,n) converts the binary image BW to an indexed image X with colormap gray(n). If n is omitted, it defaults to 2.

n must be an integer between 1 and 65536.

Class Support

The input image I can be logical, uint8, uint16, int16, single, or double and must be a real and nonsparse. The image I can have any dimension. The class of the output image X is uint8 if the colormap length is less than or equal to 256; otherwise it is uint16.

Example

Convert an intensity image into an indexed image and then view the result.

I = imread('cameraman.tif');
[X, map] = gray2ind(I, 16);
imshow(X, map);

See Also

grayslice, ind2gray, mat2gray

getsequence graycomatrix