ind2gray (Image Processing Toolbox)

Convert an indexed image to an intensity image

Syntax

```
I = ind2gray(X,map)
```

Description

I = ind2gray(X,map) converts the image X with colormap map to an intensity image I. ind2gray removes the hue and saturation information from the input image while retaining the luminance.

Class Support

X can be of class uint8, uint16, or double. I is of class double.

Example

load trees
I = ind2gray(X,map);
imshow(X,map)
figure,imshow(I)

Algorithm

ind2gray converts the colormap to NTSC coordinates using rgb2ntsc, and sets the hue and saturation components (I and Q) to zero, creating a gray colormap. ind2gray then replaces the indices in the image X with the corresponding grayscale intensity values in the gray colormap.

See Also

gray2ind, imshow, rgb2ntsc

imwrite ind2rgb