changing hue and saturation, then back to RGB

[Anderson, Charles (DNR)]

I'd lilke to take a RGB jpg image, rotate the hue by +40 degrees, ~double the saturation, and save result as a RGB jpg for later color segmentation.

Color Inspector 3D plugin will do exactly what I want except that it will only "save modified image" as a smaller tiff file (with smaller width and height) and does not produce a macro.

Threshold Color works well on my original RGB jpg files, but I think changing hue and saturation first would allow better segmentation in batch mode over many images taken under somewhat varied lighting conditions.

Any suggestions or example macros will be greatly appreciated. Pardon me if I've missed something obvious.

Thanks

Charles

[Gabriel Landini]

On Saturday 27 Aug 2011 20:53:40 Anderson, Charles (DNR) wrote:
> Threshold Color works well on my original RGB jpg files, but I think
> changing hue and saturation first would allow better segmentation in batch
> mode over many images taken under somewhat varied lighting conditions.

It will not. Rotation of the hue will not make any improvement for the
threshold colour plugin. If the range of hues spans the 255-0 gap, use the
opposite filter checkbox (stop instead of pass).
To duplicate the saturation, convert to HSB, then apply Math Multiply and use
2 as the value, then conver back to RGB, but again, this is not likely to
improve the "segmentability" of the image and likely to lose the high
saturation values (as anything >127 will become 255).

Cheers
G.

[Michael Schmid]

Hi Charles,

for color segmentation, you could also try the 'Versatile Wand' plugin -
it has separate sliders for (gray) value and for how much it is sensitive
to hue. It uses a different algorithm than Gabriel Landini's Color
Threshold, both have advantages and disadvantages.

If you want to process many images with the same colors, you will probably
use the 'eyedropper color' instead of clicking to a point with the
prototype color in each image, and you will probably use the
non-contiguous mode.

http://imagejdocu.tudor.lu/doku.php?id=plugin:segmentation:versatile_wand:start

Michael
___________________________________________________________________________

On Sat, August 27, 2011 21:53, Anderson, Charles (DNR) wrote:

> I'd lilke to take a RGB jpg image, rotate the hue by +40 degrees, ~double
> the saturation, and save result as a RGB jpg for later color segmentation.
>
> Color Inspector 3D plugin will do exactly what I want except that it will
> only "save modified image" as a smaller tiff file (with smaller width and
> height) and does not produce a macro.
>
> Threshold Color works well on my original RGB jpg files, but I think
> changing hue and saturation first would allow better segmentation in batch
> mode over many images taken under somewhat varied lighting conditions.
>
> Any suggestions or example macros will be greatly appreciated. Pardon me
> if I've missed something obvious.
>
> Thanks
>
> Charles
>