Convert RGB image or colormap to grayscale image
This function converts color image to gray image.
RGB2gray(img, method = "average", weights = NULL)
img |
target image, specified as an |
method |
character, procedure for converting color to grayscale. Available methods
are |
weights |
weights for red (R), green (G), and blue (B) channels. Required if
|
Grayscale image, returned as an nrow-by-ncol numeric matrix with values
in the range [0,1].
RGB2gray converts RGB values to grayscale values by forming a weighted sum
of the R, G, and B channels.
data(twelve) par(pty = "s", mfrow = c(1,3)) plot(as.raster(twelve)) # in RGB title(main = "original", font.main = 1) x <- RGB2gray(twelve, method = "RMY") plot(as.raster(x)) # in grayscale title(main = "RMY", font.main = 1) x <- RGB2gray(twelve, method = "ITU") plot(as.raster(x)) # OMG! 12 is gone... title(main = "ITU", font.main = 1)
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