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Webcam Long Exposure Software

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#1 JoseBorrero

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Posted 30 May 2010 - 10:02 PM

Hello Guys

I found this little program that can produce long exposures on any webcam, I think.
here's the link: http://www.nimisis.c...ts/exposure.php

the software is called "exposure v 1.0".Let me know how it work on astrophotography.

thanks and enjoy!

#2 Edward E

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Posted 02 June 2010 - 01:12 PM

Looks interesting. Thanks Jose for the heads up and link. I see that they tested it on a Philips SPC 900 which is ~ Celestron's NexImager. I will give it a try on a bright DSO(s) and see what happens.

#3 Edward E

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Posted 03 June 2010 - 10:29 AM

Downloaded ““Exposure”” and installed it on my HP Laptop with Win 7.

“Exposure” installed quickly with no issues. The GUI interface is very simple and is accompanied by 3 screens (1 real time image and two time lap exposure screens). There is no help menu but there is a FAQ button that takes you to the web page were you download the application. Here you will find a FAQ section on the left of the page. The application is run with a single button that toggles between “start” and “stop” when pressed.

I first tried using ““Exposure”” with my ageing Logitech web cam. “Exposure” saw the webcam and in a matter of seconds I was taking a 2 minute exposure of the tree in the front yard at night. I then closed “Exposure”, unplugged my Logitech webcam and plugged my in Celestron NexImager. Checked the NexImager with “Craterlet” application to make sure the NexImager was working, it was; also checked NexImager with “AMCap” application, again the camera was working. Closed out “Craterlet” and AMCap and started “Exposure”. “Exposure” sees the NexImager as a Phillips SPC 900 N, same as AMCap but all I could get were grayed out screens. I tried a 1 & 2 minute exposure(s), still “Exposure” displayed grayed out screens. There is a paragraph under the FAQ section about gray screens but it only stated that in this case the camera was not working and to try another camera. So I was left with an application and camera that worked but would not work together. By this time it was late and I did not do any further test.

My first impression of “Exposure” is that it shows promise for long exposures with a web cam and those of you with a mod-Logitech web cam should give it a go. If you have a NexImager, like me, it may take some work to get it working.

If you have any suggestions about getting the NexImager to work, please post and I will give your suggestion a try.

#4 groz

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Posted 03 June 2010 - 10:15 PM

Is it actually doing long exposures ? Or is it just stacking short exposures on the fly? If it's actually doing a long exposure, that's a pretty neat trick, considering that unmodified, most webcam hardware isn't actually capable of it. If it's just stacking on the fly, well, that's not the same as a long exposure. I can take 1/5 second exposures all night long with my Neximage, and stack hours worth of them, it still wont register a mag 10 star in that image, no matter how many I stack. But do a true 2 second exposure, and the mag 10 star will stand out clearly, and one can probably detect mag 11 stars in the image too.

#5 Koen Dierckens

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Posted 04 June 2010 - 04:35 AM

Is it actually doing long exposures ? Or is it just stacking short exposures on the fly? If it's actually doing a long exposure, that's a pretty neat trick, considering that unmodified, most webcam hardware isn't actually capable of it. If it's just stacking on the fly, well, that's not the same as a long exposure. I can take 1/5 second exposures all night long with my Neximage, and stack hours worth of them, it still wont register a mag 10 star in that image, no matter how many I stack. But do a true 2 second exposure, and the mag 10 star will stand out clearly, and one can probably detect mag 11 stars in the image too.


The FAQ answer on the website will disappoint you:
Q10: Do you have any tips for a better result?
A10: The higher the webcam resolution, the better. And also having a high frame rate webcam (i.e. 30Hz or 60Hz) should yield more fluid looking images. Note that Exposure is only simulating long exposure. The software has no control over shutter timings, after all, CCDs on webcams do saturate after prolonged exposure. Images saved in uncompressed formats will also lack compression artefacts (see Q9).

#6 Koen Dierckens

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Posted 04 June 2010 - 04:53 AM

Edward,

The FAQ also states:
If a dark grey box is being shown, it might be due to interference from other webcam software that is already running. Please close these down and try again.
So even with your procedure of unplugging and replugging webcams, there either might remain a primary entry of the Logicam in the registry (but then one would expect that the soft wouldn't recognise your Neximager webcam), or , by plugging in first the Logitech, some Logitech drivers/applications loaded in the background and then interfered with the "Exposure"/Neximager combination.

Maybe a reboot or a complete uninstall of the Logitech webcam followed by a reboot might do the trick in enabling full functionality of the Celestron webcam.

On the other hand, regarding the fact that the application only simulates long exposures, I wonder if it gives an additional advantage over common stacking software (Registax, ...). ??

#7 psonice

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Posted 04 June 2010 - 07:36 AM

It's just doing stacking, so I doubt it has any 'advantage' over stacking software unless it's doing some cool stuff at the same time (doesn't seem like it).

I've written some software pretty much the same as this for mac, for doing timelapse imaging. It just combines frames from the camera over a long period (1 minute in my case, although it's easy to change) to produce a long exposure type effect (motion trails on moving objects). It's in no way equivalent to a real long exposure because the frames are averaged instead of added (otherwise you'd get a white image after half a second during the daytime!)

That said, this method does have some advantages. If you handle it right, you CAN capture faint objects that aren't visible in the original image, much like a long exposure (but not as good!). You can do that because faint objects can be present in the image, but just hidden in the noise and very dark. Increasing the brightness doesn't help, because you just see noise. But combining a ton of frames removes most of the noise, so the object becomes detectable.

I did some experiments with this, with some astronomy imaging software I'm writing. I captured using a built-in webcam, in a near totally dark room. The image on screen looked 100% black (see http://www.interealtime.com/1.jpg ). With some enhancement I could make out a rough shape of the furniture in the room. With 'long exposure', and some pretty heavy enhancement, I got a clear, fairly detailed image of the room! (See http://www.interealtime.com/5.jpg ). So this kind of long exposure really does help!

There is one HUGE advantage over stacking software too: this is realtime (at least i'm assuming this pc software is? If not, meh...) That means you can quickly see what you're imaging at the scope, rather than capturing for a few minutes, stacking, then processing. It saves a bunch of time, and it's a lot less fiddly and error prone.

This is the reason for me writing my own imaging software - it's 100% realtime, so you can do the stacking and post-process with a live video feed or ccd sensor, and get pretty much the same results as you'd get sitting around all night and spending half of the next day stacking and playing with photoshop. You can see immediately if something is going wrong. And it also means you can do something like 'enhanced viewing' - getting a good live view of those dim DSOs that you can normally barely see :) Not that it's perfect mind, it's not going to replace a high end setup and software that can take hours squeezing detail out of the images. If it comes close, I'll be happy.

One thing to be aware of with all this btw: high bit-depth images are absolutely critical if you're after dark objects - if it saves out as regular 8-bit images, you lose so much information it's almost worthless. A minimum of 16bit TIFF or PNG (or similar) is needed, 32bit is better. And if it's not processing in 32bit internally, the best you can hope for is to get rid of some noise.

#8 NeoDinian

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Posted 04 June 2010 - 08:21 AM

So it works almost like the Astro-Vid cameras do... Stacking on the fly...

Even though it's not true long exposures, it would still prove useful for astronomy.

#9 Edward E

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Posted 04 June 2010 - 12:16 PM

I found the problem last evening. I opened the device manager and disabled a speaker device that was created when the NexImager drivers were installed. Once I did that, NexImager started working with "Exposure". I plan to hook it up to my C11 this weekend and see what happens on a bright DSO like M3, M13 or M81.

I like the real time mode "Exposure" has, but I'm not sure that this application will turn a planet cam into a rudimentary DSO cam but it will be fun to try it out.

#10 tk89123

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Posted 04 June 2010 - 06:12 PM

Am I correct in assuming that this is a Windows application? I didn't see anywhere on the website what operating system it's for. Maybe I'm just blind. Funny, software used to always have "system requirements". :scratchhead:

#11 Edward E

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Posted 04 June 2010 - 07:02 PM

:jump: I did state that my HP laptop is using Windows 7.

#12 avarakin

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Posted 05 June 2010 - 11:10 PM

psonice,

Did you try your stacking software with telescope? If yes, what magnitude you were able to detect?

#13 Edward E

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Posted 08 June 2010 - 10:26 AM

I did not have a chance to try this app out over the weekend, do many honey do projects. I will try to check it out this week; stay tuned...

#14 TexomaAU.Obs.

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Posted 10 July 2010 - 08:44 AM

Edward, I am awaiting your testing of the Nimisis...:praying:
All sounds promising, I have several modified webcams, including Meade's Color CMOS USB cam and I cannot get nothing but planetary and bright stars such as Vega....

#15 Edward E

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Posted 12 July 2010 - 10:04 AM

Nope, not yet. Between honey-do projects, work, vacation and in-law visits I have not had time to check it out. Things seem to be slowing down so I hope to get to it shortly. Stay tuned...


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