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Messages - pfile

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General / Re: getting L* back into RGB- failing
« on: Today at 02:32 »
well maybe i have misread that flow, but i thought what was happening is that you extract the L* from the RGB, then modify that L* by linear fitting it to the L, and then put the modified L* back into the RGB. in theory this should make the (perceptual) brightness of the RGB match that of the L you are going to combine it with.

i misunderstood this at first, not realizing that it was intended to normalize the brightness of the RGB and L. which is why i was saying, why not do it the other way around - dim or brighten the L to match the RGB, so that you dont need to re-inject the L* back into the RGB.

so even though the L* of the RGB gets replaced during LRGBCombination, it was necessary because the L and the RGB should be of similar brightness when you run LRGBCombination. pretty much all i have been trying to say is that if you process the L and the RGB similarly (for instance, using AutoSTF to stretch both images) then they should already be compatible, and this linearfit step should not be necessary.

at any rate i dont think anyone can really debug whats going wrong with your images unless you post them somewhere so that we can look.


dont know if this is your problem, but the histogram in DPP/Photoshop is that of a default stretch. with a centered histogram in these programs you are actually very much underexposed. i used to use +2EV when i used a DSLR and that yielded a reasonable exposure in linear mode.

a 2nd possibility is that the bias and or darks could be wrong and so are indeed leaving 0 signal in the result. can you check the calibrated images and see what they look like?


General / Re: getting L* back into RGB- failing
« on: 2018 March 17 17:31:23 »
thats fine

however the point is that they need to be comparably stretched, which is what they have both said in the past. one question is, why not fit the stretched L to the extracted L* and save the step of re-inserting the L* back into the RGB? ostensibly both your stretched L and stretched RGB look good to you, so i don't see why you have to do it the other way around. there's nothing stopping you from adjusting the image after the merge.

and also the extraction of L* in either case is touchy. do you set the RGB weights and gamma to 1 first? or is it OK that the L* is perceptual?


General / Re: getting L* back into RGB- failing
« on: 2018 March 17 15:27:27 »
never had to do that. i understand what is being driven at with that flow, but if you stretch your RGB and L similarly in the first place (for instance by using autoSTF on both) then it is not necessary.


General / Re: getting L* back into RGB- failing
« on: 2018 March 17 05:58:43 »
hm... well without seeing the input images to LRGBCombination it's hard to guess at what's going wrong...


General / Re: getting L* back into RGB- failing
« on: 2018 March 17 05:35:50 »
that is correct, leave RGB blank, and only load name of the L image into LRGBCombination, then apply to the RGB. make sure there is no mask enabled on the RGB image. i've never messed with the channel weights, but i think most people will boost the saturation a little (by making the saturation number smaller; the control is "backwards").


General / Re: getting L* back into RGB- failing
« on: 2018 March 17 03:50:03 »
hm, i have never used a flow like that. i am not sure what the point is of putting the L back into the RGB image and then immediately replacing it by way of the LRGB combine. maybe troy can comment.

i would just skip the last 3 steps before LRGBCombine and instead just apply the processed L image to the RGB image using LRGBCombination.


Bug Reports / Re: ALT-N and ALT-E not working on Mac in 1.8
« on: 2018 March 15 16:11:36 »
i can only guess that function keys on OSX are a little weird, since they are repurposed for backlight control, etc. to generate the actual function key keycodes you probably need to hold down the "fn" modifier key.

as far as the shortcuts go, they are identified in contextual and menubar menus. for instance Image > STF Autostretch shows clover-A as the shortcut, and right clicking on an image and selecting Screen Transfer Functions will show the STF contextual menu, where control-S is shown as the toggle shortcut.


Bug Reports / Re: ALT-N and ALT-E not working on Mac in 1.8
« on: 2018 March 15 01:54:16 »
should be command-A to compute and apply an STF and control-s to toggle the STF on OS X

General / Re: Big Pink Stars after ArcsinhStretch
« on: 2018 March 15 01:52:16 »
ok, that makes sense. i was going off what happened to me while processing DSLR eclipse images - the red channel was totally blown out while the blue and green were not, leading to some funny stuff happening.


General / Re: Big Pink Stars after ArcsinhStretch
« on: 2018 March 14 16:03:14 »
i'm not entirely sure that the problem is caused by MLT, i think it might be an artifact related to 14-bit cameras. you see this all the time in DSLR images of M42, where the core comes out pink. i think it could be because the image is saturated in the red channel only, and then when stretched it comes out pink since in 16-bit space the saturated red channel is not actually saturated. it's as though it's an image of something strongly colored red which becomes washed out to pink as it is stretched.

it's possible using rescale on each channel before color calibration would help with this problem, i am not sure.


General / Re: FITSHeader - how to add
« on: 2018 March 09 04:50:03 »

Image Processing Challenges / Re: Blotchy result from DBE
« on: 2018 March 05 16:32:19 »
you have samples placed on stars or on the halos of stars... youll need to carefully move them off, using the dark parts of the original DBE as a guide.

General / Re: ArcsinhStretch and White Center in Stars
« on: 2018 March 04 23:26:21 »
as ChoJin has noted, the deconvolution step tends to push energy to the center of the star, sometimes saturating them - to see this turn the STF off and then undo/redo the deconvolution. you'll see the bright stars go from more gaussian shapes to white discs at the core. so it helps to mask just the star cores while doing deconvolution.


General / Re: dynamic crop does not work
« on: 2018 March 03 16:35:15 »
you should be able to drag the DynamicCrop step out of the image history of your cropped image and drop it onto your 2nd image, give that a try.


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