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C++ API

: I = ind2gray (x, map)

Convert a color indexed image to a grayscale intensity image.

The image x must be an indexed image which will be converted using the colormap cmap. If cmap does not contain enough colors for the image, pixels in x outside the range are mapped to the last color in the map before conversion to grayscale.

The output I is of the same class as the input x and may be one of uint8, uint16, single, or double.

Implementation Note: There are several ways of converting colors to grayscale intensities. This functions uses the luminance value obtained from rgb2ntsc which is I = 0.299*R + 0.587*G + 0.114*B. Other possibilities include the value component from rgb2hsv or using a single color channel from ind2rgb.

See also: gray2ind, ind2rgb.

Package: octave