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Messages - pfile

Pages: [1] 2 3 ... 238
1
General / Re: HDRComposition
« on: 2018 June 13 17:40:26 »
are these RGB images? there is only one binarizing threshold applied to each image, so if one of the channels is out of whack with the others, the binarizing threshold may not "work".

one strategy would be to split the images into R G B components and try doing the HDRComposition 3 times

rob

2
General / Re: HDRComposition
« on: 2018 June 13 17:13:09 »
experiment with changing the binarizing threshold

rob

3
General / Re: Poject question - history is not being saved
« on: 2018 June 04 22:06:23 »
how do you know that the history is not being saved?

i have never seen this happen...

rob

4
General / Re: photometric colour calibration error
« on: 2018 June 04 04:50:22 »
i don't think there is an issue with running PCC on the input frames per-se, however, due to the scaling process during integration the relative weights between the channels in the input frames would probably be different from the relative weights in the output frame. i think there's not much choice but to run color calibration on the integrated frame if you want to get correct colors. you might try the older color calibration flow and see what happens.

rob

5
cool. i forgot to mention that a bad sample is one which is brighter than the tolerance value allows - DBE thinks it's all signal and no background.

if you have a serious gradient in a nebula-type image which has signal all over the place, you can't always tell if your samples are on mostly background or mostly signal. so you can remove the gradients without regard to that, then place the samples more carefully/properly on the DBE'd image, save the process icon, and then discard the original DBE'd image and re-run on the original image with the better sample points from the trial run. you still have to crank up the tolerance but hopefully you're only sampling the gradient that way.

rob

6
incrementally increase the sample tolerance value and click resize samples until all the samples turn from red to white. resize just forces them to redraw. note - do not click generate, it will replace all of your samples!

rob

7
General / Re: photometric colour calibration error
« on: 2018 June 01 16:51:14 »
yes i agree with mike. PCC uses 'aperture photometry' as a default method, meaning it has to detect stars and then compute an aperture for each star over which to sum the flux. i'm saying that PCC might be having problems 1) detecting stars in the image (as evidenced by the low star count and how hard it is to solve this image) and 2) computing correct apertures for the detected stars due to their profiles.

the 'detected stars' map is going to show you what stars PCC identified for photometry. i think it's an important debug tool here - you can evaluate just how many stars it can detect, and which, to see if those stars have meaningful color data.

one possibility would be to perform deconvolution on the image in order to tighten up the stars, but you have to be careful there as the decon could saturate the centers of otherwise unsaturated stars, again perhaps throwing the PCC calculation off.

on the theory that you have saturated star data which has shown up as unsaturated pixels, it might make sense to run Rescale in individual channels mode on the image to get those saturated stars into the ~1.0 range. this is a longshot though because i am not sure if that really will cause PCC to exclude them. the heart of this problem is that DSLRs have 14-bit sensors and when PI reads this data in, it stuffs the data into the lower 14 bits of 16 bit integers. so saturated pixels in your original CR2 end up with a value of 0.25 or thereabouts in the 16-bit data. so the saturated pixels suddenly don't look saturated, but you can see that the stars are "flat" with your eye - the whole center of the star has a value of 0.25. what i am not sure about is if PCC can understand that the star data is no good in this situation, and so perhaps the rescaling would help it out.

rob

8
General / Re: photometric colour calibration error
« on: 2018 May 31 18:10:43 »
it is a difficult image to solve due to the quality of the stars. it may or may not solve but it does not follow that this is all PCC needs to be successful. i would tick the "detected stars" in PCC and see what is happening. from mike's screenshot there are very few stars in the graph, so you can't expect a high quality regression.

if the stars PCC detected are overexposed, the color calibration will be wrong. GIGO.

rob

9
General / Re: photometric colour calibration error
« on: 2018 May 31 17:47:37 »
imo, overall, the stars in this image are not of high quality - focus could be off and it does seem to suffer from coma (is this a newt?)

to start with a narrow FOV image of this target is an area of the sky with a dearth of stars, and then i think PCC is not detecting most of the fainter stars in the image because they are really soft and not super star-like. with so few detections the quality of the PCC result is going to be poor... perhaps if you did a pass of deconvolution first it could help.

another issue is that i think the brighter stars are probably saturated - in the red channel for sure, but maybe all channels. but because of the way DSLR images are handled in PI, the stars don't end up saturated at 1.0 but at some other (lower) level, in the vicinity of 0.25. if that happens to too many stars the PCC result will be bad as the true color of the star is lost - they don't "look" saturated to the tool as the values are not high enough. then again i'm not sure if PCC tries to exclude saturated stars but even if it did i don't think it would detect these stars as being saturated. anyway you'd have to turn on the "show detected stars" checkbox in PCC to see which stars it's actually using and try to figure out whether they are overexposed or not.

rob

10
General / Re: Combining Images from 2 Different cameras
« on: 2018 May 27 16:18:53 »
i guess you can also use the MosaicByCoordinates script which does the same thing internally - i've never had it fail due to resource limitations (in fact i don't think it's ever failed...) but maybe you are dealing with super widefield images? even still i just saw an example of a really wide-field image done with MBC so it should work.

rob

11
General / Re: Combining Images from 2 Different cameras
« on: 2018 May 27 04:24:30 »
not sure if this is what the OP is after, but in your case why don't you just use StarGenerator to make a synthetic reference image with the right center coordinates, desired image scale and size and use that instead of the first 3 steps?

rob

12
General / Re: Problem calibrating Red channel frames only
« on: 2018 May 23 16:41:12 »
no, in theory there shouldn't be the need to use maxim to calibrate.

perhaps the flat sub calibration was funny - i usually just calibrate my flats with bias frames since the flats are relatively short. but i think BPP always tries to load and scale any darks that are present. i've been using PI so long that i never use BPP so for me its easy to do the flat calibration the way i want. i guess since BPP works right on the other flats then there must be something different about the red flats but that seems unlikely (unless the maxim config changed somehow between the GB and the R flats)

anyway, at this point i'm not sure what the problem really is.

rob

13
General / Re: Problem calibrating Red channel frames only
« on: 2018 May 23 05:41:41 »
OK i didn't try making the flats out of the flat subs with PI... maybe there is still some problem.

BPP should set up ImageCalibration the right way, meaning it knows that it always creates Master Darks which are not bias subtracted, so when it calls ImageCalibration it sets it up right (meaning, master dark need to be bias subtracted, which is what Calibrate in the master dark section does.)

so i don't know what's wrong i guess. you might try running ImageCalibration manually (which is what i did) and see if you get the same result with the maxim master flat. maybe there is some problem with the BPP-generated master flat that is not present in the Maxim-generated master flat?

rob



14
General / Re: Gradient Merge Mosaic Error
« on: 2018 May 23 03:56:18 »
yeah MBC is awesome. Andres has really written some very useful tools for PI!

which reminds me, he also wrote a mosaic planner which is very cool too.

rob

15
General / Re: Problem calibrating Red channel frames only
« on: 2018 May 23 03:54:26 »
first thing is, it looks like the master bias and master dark came out of pixinsight, but the master flat was created with maxim? usually that's not a good idea to mix calibration frames like that.

second is, master darks created by the BPP script are uncalibrated, so if you load both the master bias and the master dark when calibrating a light, you need to tick "calibrate" in the master dark section.

if i load all 3 masters and calibrate the light (with dark calibration as mentioned above) it seems to work mostly OK, but the light is very slightly overcorrected on close inspection. it would probably help to remake the master flat in Pixinsight.

rob



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