When to create synthetic Luminance?

[joelshort]

When creating a synthetic luminance, when is the best time to do so?  Before any processing, or after DBE/ABE etc. before stretching?

I'm working with LRGB information and I'd like to combine the master R, G, and B files into a synthetic LUM with the real LUM.  To do so I'm planning to Integrate the 4 master images (LRGB) using noise weighting without normalization.  Is that correct?  If I'm right that should give more weight to the real LUM and lesser weight to the RGB but still include some for a smoother synthetic LUM.

[vicent_peris]

Hi,

If you have strong gradients, it could be better to generate the synthetic luminance after cleaning the color image with DBE. In any case, the synthetic luminance should be assembled always before stretching.

It doesn't matter which normalization you select, the result will be the same. What's important is to enable the noise weighting, and disable any outlier rejection. Actually you can leave ImageIntegration with the default parameters.

Please, don't try this technique if you're binning your RGB images.


Best regards,
Vicent.

[joelshort]

Perfect Vince, thanks.