From the
linked blog postWhen the shutter button is pressed the app waits a few seconds and then records up to 64 frames with the selected settings. The app saves DNG raw files which can then be downloaded for processing on a PC.
Nothing needs to be added to CHDK to do this. All the smarts are on the PC, which given the wimpy processors on our cameras, would be the right way to do it with CHDK as well.
On each occasion he shot an additional burst of black frames after covering the camera lens with opaque adhesive tape. Back at the office the frames were combined in Photoshop. Individual images were, as you would expect, very noisy, but computing the mean of all 32 frames cleaned up most of the grain, and subtracting the mean of the 32 black frames removed faint grid-like patterns caused by local variations in the sensor's black level.
Again, nothing special here, dark frames and stacking are well known techniques. The enabling element for phones is raw images and an intervalometer, which CHDK can already do. In fact CHDK has the advantage here, because individual frames can be as long as the scene permits:
The camera cannot handle exposure times longer than two seconds. If this restriction was removed we could expose individual frames for eight to ten seconds, and the stars still would not show noticeable motion blur. With longer exposures we could lower the ISO setting, which would significantly reduce noise in the individual frames, and we would get a correspondingly cleaner and more detailed final picture.
You could use a script like my fixedint.lua script to take the frames
http://chdk.wikia.com/wiki/Lua/Scripts:_Fixed_Exposure_IntervalometerDark frame and stacking workflow is up to you to develop, but there are many tools available. Doing scenes like the golden gate or lighthouse with CHDK should be quite easy.
Compensating for movement between frames or aligning both stars and background scenery are require more software trickery, but again, this is much better done after the fact on a PC. The author of the blog post does this with photoshop.
SeeInTheDark would be much more difficult, if not impossible to reproduce with CHDK.
* It shoots long bursts rapidly, which is not possible with raw in CHDK. Raw video ala Magic Lantern could potentially help, but I remain unconvinced this a possible on P&S hardware. In any case, much work would be required to even find out. Not an issue for tripod shooting static scenes.
* Much of the "magic" involves aligning the images, which is done using both advanced image processing and phone sensor data.
* The processing power available on the cameras is far less than modern smart phones, so the software part is likely impractical to do on camera.
* Some comparable sensor data might be available from the IS system, but it would require significant reverse engineering and likely is not extensive as what is available from smartphones. For example, lens based IS can't compensate for rotation around the lens axis, so there's no reason for the IS system to measure it.
