Cannot recombine R G B images, keep getting error msg

[Rudy Pohl]

Hi there:

I'm still pretty new to PI and learning how to do the Linear Fit method for color calibration. I have extracted the L image and the R G and B images and used Statistics to find which has the lowest media value, in my case Green. I do the linear fit method by dragging the triangle from the Green image onto the Blue and then the Red.

However, when I try to recombine these image using the LRGBCombine tool it doesn;t work and an error message pops us which reads:

"LRGBCombination

Cannot execute instance on view 45_NEFs_PI-stacked_copy2_L
Reason: LRGBCombination cannot be executed on grayscale images."

I have clicked various combination of things and clicked the reset button on all tools but no success.

Does anyone have any idea what I might be doing wrong?

Thanks very much,
Rudy

[RickS]

Are you trying to drag and drop the LRGBCombination new instance triangle onto a grayscale image?  That will generate the error message you mention.  What you need to do is load the R, G and B images (and optionally L) and then click on the round "apply global" icon.

[Rudy Pohl]

 Hi Rick,

Yes, that's exactly what I was doing wrong. It now worked the first time. Thanks so much.

Best regards,
Rudy

[RickS]

Glad I could help, Rudy!

FYI, there is one other common use case for LRGBCombination that does involve the new instance icon: you can combine a Luminance image with an existing RGB image by selecting the Lum in LRGBCombination (untick the R/G/B) and then dragging and dropping the new instance icon on the RGB image.  I use this very frequently as I usually process Lum and RGB data separately and combine them near the end of processing.

Cheers,
Rick.

[Rudy Pohl]

Thanks Rick, I just discovered this very step half an hour ago, works great!

Cheers,
Rudy