| Image Processing Toolbox™ | |
[Y,newmap] = imapprox(X,map,n)
[Y,newmap] = imapprox(X,map,tol)
Y = imapprox(X,map,newmap)
Y = imapprox(...,dither_option)
[Y,newmap] = imapprox(X,map,n) approximates the colors in the indexed image X and associated colormap map by using minimum variance quantization. imapprox returns indexed image Y with colormap newmap, which has at most n colors.
[Y,newmap] = imapprox(X,map,tol) approximates the colors in X and map through uniform quantization. newmap contains at most (floor(1/tol)+1)^3 colors. tol must be between 0 and 1.0.
Y = imapprox(X,map,newmap) approximates the colors in map by using colormap mapping to find the colors in newmap that best match the colors in map.
Y = imapprox(...,dither_option) enables or disables dithering. dither_option is a string that can have one of these values. The default value is enclosed in braces ({}).
Value | Description |
|---|---|
{'dither'} | Dithers, if necessary, to achieve better color resolution at the expense of spatial resolution. |
'nodither' | Maps each color in the original image to the closest color in the new map. No dithering is performed. |
The input image X can be of class uint8, uint16, or double. The output image Y is of class uint8 if the length of newmap is less than or equal to 256. If the length of newmap is greater than 256, Y is of class double.
imapprox uses rgb2ind to create a new colormap that uses fewer colors.
Approximate the indexed image trees.tif by another indexed image containing only 16 colors.
[X, map] = imread('trees.tif');
[Y, newmap] = imapprox(X, map, 16);
imshow(Y, newmap) | imagemodel | imattributes | |
| © 1984-2008- The MathWorks, Inc. - Site Help - Patents - Trademarks - Privacy Policy - Preventing Piracy - RSS |