Topic: Better quality with image stacking (Page 1 of 1)

I learned some years ago that amateur astronomers use some pretty interesting techniques (image stacking) for enhancing the image quality of cheap cameras and even webcams to take amazing pictures of the stars and planets.

Does anyone have any experience with this?

I've managed to dig up 2 names: Helicon and CombineZ. Haven't yet had time to test either one.

What I would ultimately like to do is this: take x number of pictures of a static object and combine them into 1 really hi-def image. It would be really cool if the application could also be used for pictures that have semi-static object such as trees/grass swaying in wind etc.

edit: Another name that bubbled up: Registax

(Edited by Arthurio on 08-27-2008 15:12)

Coool. Of course, being a nerd, I heard about the technique but never had the curiosity to look for such softs. Thanks for sharing.

tks Arthurio... great stuff.

I'm sorry but I'm very cynical about these photos...are they doctored.?

How can you create or restore detail when it was never captured by the lens. It's like ripping out 50 pages from a book and expecting software to fill in the blanks.

I've worked enough with Photoshop to know you can bring out hidden detail related to poor exposure and you can certainly sharpen a photo...but this is pushing it - the kind of stuff you see in movies like Mission Impossible.

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The link I gave isn't the only one ... you can just google image stacking astronomy or something like that and there are thousands of people who use these techniques...

here's an explanation http://cs.astronomy.com/asycs/forums/p/20248/310166.aspx

Ok..but the detail in those photos is still very poor overall...compare that with the pretty sharp photo of the fly's compound eye.

Nature & Travel Photography
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The fly picture is made with a slightly different technique ... by combining the sharp parts of several photos that have their focal points set at different distances. I'm guessing the program uses sharpness/contrast data to generate much more precise masks than a human could. Besides why do I have to defend these things ... the information is there ... just read up and try it out for yourself if the thousands of images on the net don't satisfy you.

Anyway ... back to regular image stacking.

I did some real life testing.

Canon 400D with 70-200 f4 L in low light @ ISO 1600 @ 200mm and 1/4s exposure from distance of 4.5m from the boring empty plastic bottle...

I made 256 images such as these:

example 1 - 100% crop


example 2 - 100% crop


I used Photoshop CS2 to combine the images with "Load Files into Stack..." script (auto align on) and stack mode set to "Median".

Result:


"Zoomed in" at 900% with "Bicubic Smoother"


The focus could have been better if I had been luckier but 400D isn't known for it's good low light focus...

As you can see there's quite a bit of information in the resulting image that would have been impossible to extract from any of the source images ... of course it seems pretty obvious since what it all comes down to is just artificially elongated exposure ... the important bits are: aligning the images perfectly and then combining the images with an average or median function which ultimately improves the signal to noise ratio.

(Edited by Arthurio on 08-30-2008 23:48)

Interesting stuff.
As it happens I've been playing around with stacking in Photoshop recently myself to try to achieve numerous different effects like HDR, Lomo, "hyper-reality", directed focus or wider focus ranges as discussed here.

I've nothing of note to show as yet but I thought I'd throw in this link which I found very useful. Ever hears of Dr Brown?

Arthurio, I have the same camera as you and I find I get better results in any light going for manual focus, especially if it is a still life macro you're shooting.
I tried to follow the steps you outlined:

quote:

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Arthurio said:

I used Photoshop CS2 to combine the images with "Load Files into Stack..." script (auto align on) and stack mode set to "Median".

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I'm using CS3 extended and "Load Files Into Stack" does not have the option to set the stack mode to "Median" or anything else for that matter. Unless you mean set layer blending mode of all the layers to "Median"?
I've also never tried to load 256 images into Photoshop at once either, how did that go for you and your computer's RAM?

Ooeer I can feel some juicy experiments formulating on the back burner.


Those who look for monsters should look to it that
they do not become monsters. For when you gaze
long into the abyss, the abyss also gazes into you.

My eyes aren't good enough to do manual focusing with that precision. Aperture for these images was f4 so that must have contributing to the general blurriness as well.

When importing the images with "Load Files into Stack..." I had both auto align and create smart object checked ... then from the Layer menu -> Smart Object -> Stack mode -> Median. I had precropped all the images with Digital Photo Professional before importing into Photoshop otherwise it would have been impossible and even then all the processing took a long time and Photoshop's memory usage peaked at 1.6GB.

Never heard of Dr Brown. Thanks for the link, looks interesting.

Ah I see ta.
I should have added that there is a great little video tutorial on the Dr Brown page as well as some groovy scripts to further heighten your Photoshop delight.
I've been using "Dr. Brown's Services 1.9.4" and the stack feature in that using PS and Bridge.


Those who look for monsters should look to it that
they do not become monsters. For when you gaze
long into the abyss, the abyss also gazes into you.