Curves transformation and masks....basic question

[sixburg]

What is the proper process to use a mask with curves transformation?  For example, to increase star saturation while protecting all else in the image.  I thought this was rather simple:  create a star mask via any of the standard approaches, apply the star mask, execute saturation adjustments in CurvesTransformation.  However, the mask is being ignored.  What am I missing?  I'm very much aware of how to create masks, but with this particular tool the masks are not recognized. 

Thanks for your help. 

[pfile]

you may have accidentally disabled the mask, check the status line at the bottom of the PI desktop to make sure that it does not say "Masked (disabled)".

also if you have inverted the mask accidentally you may be protecting the stars rather than revealing them.

rob

[topboxman]

If you use the "S" part of Component Selection for Curves Transformation, you may to want use Luminance mask to protect the background so you can control the saturation of the object and stars. Make sure the mask is not inverted and the background is red when "Show Mask" is enabled. If you want to protect the stars as well as background, you can use Pixel Math to combine Luminance and Star Mask to create single mask.

Which part of Component Selection for Curves Transformation are you trying to use with Star Mask?

Peter

[sixburg]

I've been trying to use the saturation component of curves.  I typically do a star mask by one of the various techniques.  I apply the mask, invert it to expose only the starts and start manipulating the the saturation.  I know I've done this successfully in the past, but on recent images the curves affect the entire image.  I've checked to see if masks are disabled somewhere at the bottom of the screen and see no such thing.  Plus, the masks work in other situations like noise reduction, LHE, etc.  I haven't cracked this yet, but will keep looking.  I know my masks are good...somewhere there's a switch I'm missing...

Thanks.

[sixburg]

OK...figured it out.  I was only looking at the preview where it appears the effect of the mask is not shown.

[oldwexi]

Hi!
You can switch on and off the mask in the PreviewWindow also.
On the left top side of the Preview window, the second box
is a flip flop switch to show the preview result with mask
and without mask.

If you create a starmask and you invert the mask as you said
than the stars will be hidden and the background and other object are
treated with any process.

Check the brigthness of the stars in the mask with the readout cursor.
if the value is less than 0.5 than the power of the mask is only half or less...

Gerald