Mark Smith mark at maseurope.net wrote:
This is sort of interesting:
if you simply take one of the color bytes of each pixel, and copy it
to the other two color bytes, you get a gray-scale result. The
brightness/contrast varies with which color you choose. For the few
images I've tried, it seems to be red =brighter/less contrast to
blue= darker/more contrast. This may be no surprise to the pro image
wranglers among us, but seemed intriguing to me.
And Chipp Walters chipp at chipp.com wrote:
Mark,
Unless you average the 3, your gray-scale result may not work
properly. Try it on an image with 3 circles: 100%R, 100%G, 100%B and
you'll see what I mean.
My experience is that with most photos you get a very nice grayscale
image using the red pixel and copying the value to the other two pixels
like Mark suggested.
The last public version of my "Imagedata Toolkit Preview 3" (update of
April 17)
<http://www.sanke.org/Software/ImageDataToolkitPreview3.zip>
contains both grayscale routines using "average" and those with copying
one color pixel to the other two - implemented for all three colors.
Speed for "average gray" and a 640X480 image (on a 2 GHz machine) is
about 1.1 seconds and for "gray from red" about 600 milliseconds.-
The next update of the Imagedata Toolkit, which will be the last with a
restriction to an enforced image size of 640X480, will probably be
released before Xmas and contain a number of major enhancements (among
them: scripted Rev emulation of cubic enlargement, integration and
expanding of some new Gluas filters from Gimp - translated into
Revolution - "stretch contrast", "compress contrast", enhancement of
"jitter" filters with various multi-pixel jitters, another despeckle
filter based on minimum differences between surrounding pixel pairs
[this is another Gimp/Gluas development that is identical in
effectiveness to the "median" approach, but somewhat slower], exchanging
color values within a defined range by clicking on image and/or color
scale, copying - and enlarging or shrinking - and pasting oval or
rectangular portions of an image into the same or another image with
variable fringe and/or overall blending into the basic image).
Best regards,
Wilhelm Sanke
<http://www.sanke.org/MetaMedia>
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