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Combine RGB with Lum

Mossyback
in PixInsight
I'm using a mono camera. I've processed to the point of having a RGB image and a Luminance one. In trying to combine the two using LRGB Comb. I put in the Luminance image and unchecked the RGB ones. The resulting image is solid red with no detail. What dumb mistake have I made?

Hank

Comments

  • BlockHeadBlockHead
    You need to make certain both images are non-linear (permanently stretched) using (typically) Histogram Transformation.

    -the Blockhead
  • Mossyback
    I went back and reviewed your videos on STF and HT. It was worth the effort as I now have a better understanding as to how they work and why. So, I've gone back and re-worked both the RGB and Luminance images in HT. They are now both non-linear. Again I opened LRGB put in the Luminance image and made sure the other channels were unchecked. The red is gone but the resulting image appears to be the exactly same as the Luminance image. I was expecting a colour image.

    Hank
  • BlockHeadBlockHead
    Hi Hank,

    This sounds like you do not have much color information in your RGB. (Or that your Luminance is too bright.)
    I go into great detail on this... 0.8 is the magic number you absolutely cannot be above. 

    If you want, you can make the two images available (your Stretched Luminance and your Stretched RGB) and I can look at what you are attempting to do. You might even just show a screenshot.

    -the Blockhead
  • Mossyback
    Here are the two images.
    Screenshot 2023-02-08 at 10.07.49 AM.png
    3702 x 1610 - 6M
  • BlockHeadBlockHead
    You certain you do not want to so LRGB Combination in this state.. your Luminance does not appear to be stretched. I can see a green line...
    -the Blockhead
  • Mossyback
    Sorry, I sent the wrong one.
    Screenshot 2023-02-08 at 11.23.38 AM.png
    2000 x 1546 - 2M
  • BlockHeadBlockHead
    So now... show the LRGB result of these two images.
    There should be some color... but I doubt the result will be desirable. I do not think this data is stretched well in terms of the color image. 

    -the Blockhead
  • BlockHeadBlockHead
    By the way..I will add that I do not think your color image was blended correctly.
    Your stars are very small in the color image. I think you forgot to stretch the star image when you blended the stars and the starless nebula. 

    -the Blockhead
  • Mossyback
    Thanks for pointing out what the problem might be. I’ll process the data again.
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