Posted by
ij-Newsgroup on
Nov 16, 2005; 12:05am
URL: http://imagej.273.s1.nabble.com/RGB-to-32-Bit-Gray-tp3704468p3704470.html
Hi Wayne,
I got the latest beta version and your macro works fine.
However, even with the revised version, the lookup table seems to be
inverted. For densitometry applications I would like black to stick out
as a mountain in a surface plot and white to become the lowlands. How
can I make sure black is **always** a high point in a surface plot when
using this conversion macro?
Thanks heaps! ImageJ is a great software!
Art
Wayne Rasband wrote:
>> I tried your Macro (IJ 1.35g, Windows XP). It worked however the
>> resulting 32 bit gray image turned out to be inverted,a matter of byte
>> order??
>
>
> The newImage() function was creating an image with an inverting lookup
> table. Adding 'black' (fill with black) to the second argument fixes the
> problem. Here is the updated macro.
>
> if (bitDepth!=24)
> exit("RGB image required");
> setBatchMode(true);
> w = getWidth;
> h = getHeight;
> rgb = getImageID;
> newImage("32-bit", "32-bit black", w, h, 1);
> float = getImageID;
> for (y=0; y<h; y++) {
> showProgress(y, h);
> for (x=0; x<w; x++) {
> selectImage(rgb);
> v = getPixel(x,y)&0xffffff;
> selectImage(float);
> setPixel(x, y, v);
> }
> }
> resetMinAndMax;
> setBatchMode(false);
> //run("16-bit");
>
> -wayne
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