Illtud Daniel on wrote...
| Anthony Thyssen wrote:
|
| > In the mean time you can use a LUT to reduce the number of colors
| >
| > http://www.cit.gu.edu.au/~anthony/graphics/imagick6/color/#color_lut
|
| Thanks - that's really useful. It also pointed me to a simpler way of
| doing it:
|
| If I have a 256c greyscale image with range 0-255, $image.pgm, then
| this:
|
| convert -fx 'r/8' -depth 8 image.pgm out.pgm
|
| gives me the same image but with the levels squashed into 0-31.
but the maxrgb value for the image will still be 256!
only the vlaue will be in 0-31 range!
| However, If I do:
|
| $image->Fx(expression=>'r/8');
|
I am not sure. but remember -fx uses floating point numbers with image
color values from 0 to 1.
Try doing this to 'interize' it
convert image.pgm -fx 'int(r*8)/8' -depth 8 out.pgm
Also as you are only greyscaleing the red channel you can speed things
up by only processing the red channel and separting it.
convert image.pgm -channel R -fx 'int(u*8)/8' \
-separate -depth 8 out.pgm
Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]>
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Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/
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