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19th March 2012, 13:01 | #1 | Link |
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Deshaking aircraft cockpit videos
Long time, no post... So excuse me if this isn't an appropriate forum for this.
I am a professional pilot and I am going through some videos from my training that were filmed in cockpit with digital video cameras lacking optical image stabilization. The problem with small piston aircraft (not jet) is they vibrate A LOT when the engine is running, and also from turbulence, ground roll (especially on grass) and the inevitable 'positive landings'. I am trying to clean up some of my training videos. They are not unwatchable without any deshaking, but it would make them seem much smarter if the vibration was dealt with. Does anyone have any suggestions, I was using Gunnar Thalins 'Deshaker 1.8' for VirtualDub and I am aware there is a Avisynth version. It does a fairly good job, not perfect but it helps a lot. My biggest problem with it is the zooming in and out it does. It settles down when I am flying as the motion is fairly steady and I am staying in one place in the cockpit but if there are any large movements (like pre-flight checks even with the engine off) the filter zooms in and out annoyingly. There doesn't seem to be anyway to disable the zoom function in the VirtualDub plugin, can this be done in the Avisynth version or does anyone have any suggestions for alternatives - Avisynth or not - that may help to clean up my video? Last edited by dar1us; 19th March 2012 at 13:15. |
19th March 2012, 13:35 | #2 | Link |
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Hi dar1us!
Recently i try deshake video shooting from moving car. My roadmap QTGMC for deinterlacing and Mercalli pro dad for deshaking. First I try deshake (interlaced video) and after deinterlace and result will be shake (I try also Gunar Deshaker at this step). Mercalli not free, but have a lot of setting. yup. |
19th March 2012, 14:16 | #3 | Link | |
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Quote:
Downloadable from here: http://www.guthspot.se/video/deshaker.htm Useful comparison video: |
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19th March 2012, 17:45 | #4 | Link |
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VirtualDub Deshaker performed miracles on a video I shot on a roller coaster with a point-and-shoot camera (no image stabilisation).
As pbristow said, download the latest version, and read the guide... http://www.guthspot.se/video/deshaker.htm ...and read the guide again. Did I mention that you should read the guide? Cheers, David. |
19th March 2012, 17:53 | #5 | Link |
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If you Google my name ("John Meyer") and "Deshaker" you'll see that I've written a lot about how to get good results with this particular utility (I also wrote some extensive scripts for Vegas and VirtualDub to automate using Deshaker inside of Vegas).
I've used many of the commercial programs as well. I've stabilized a lot of footage taken from small airplanes (my old man was a pilot, and I took a lot of video from his 310). I've also stabilized a lot of modern video that others have taken from various aerial platforms (including helicopters). So, I have a little experience, and based on that experience, you have several issues to deal with. First, if this is older video (taken with analog or early generation CCD digital camera), then your biggest problem will be the blur caused by camera movement. Unless you used a high shutter speed (at least 1/125, but preferably 1/500 or faster) you will find that the stabilized footage will seem to "pop" in and out of focus. This is due to the movement of the camera as the plane hits an air pocket. You don't notice this when the camera moves because your brain expects fast-moving video to be blurred. However, once the motion is removed, you are left with a frame that is blurred, whereas the adjacent frames are not. The blurring is due to the fact that normal shutter speeds are 1/60 for NTSC and 1/50 for PAL and this is too slow to prevent blur due to camera motion. There is absolutely nothing you can do about this. You simply have to decide whether the blur is less objectionable than the motion. If you haven't yet shot the video, then you should always use a high shutter speed when doing aerial video. If the video is taken with a fairly modern video camera that uses a CMOS shutter, you may also have to grapple with the horrors of CMOS "rolling shutter" artifacts. Here is an example of what can happen from the vibration from a vehicle powered by a gasoline engine. In this case it is a motorcycle engine, but the same thing may happen with video taken using a CMOS camera in a piston aircraft: CMOS Vs CCD Rolling Shutter Effect + Jello Effect Kawasaki ZX-11 In addition to the "jello" artifacts shown here, you can also get skew (where buildings appear to tilt sideways as the camera pans horizontally). The extent of these artifacts differs widely between different camera models. Some of this awful stuff can be reduced by using the "rolling shutter" reduction available in some motion stabilization software. In my experience, the Deshaker rolling shutter compensation is only marginally effective. By contrast, the Mercalli 2.0 rolling shutter reduction works much better. I highly recommend that you download and try out Mercalli if you have rolling shutter issues. Finally, since this is an AVISynth forum, you certainly should try Depan. I use this all the time to provide small corrections to my 8mm/16mm film captures. It works extremely well for removing gate weave and minor camera movements, but is not well suited for larger corrections. To my knowledge (and I may be wrong about this), I don't think it provides any facility for correcting rolling shutter artifacts. Last edited by johnmeyer; 19th March 2012 at 17:55. Reason: Added "always use a high shutter speed ..." |
2nd August 2012, 08:03 | #6 | Link | |
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Quote:
I suspect this is what some of my car cam videos suffer from, but YouTube marks this video as private, even when I log in. If not too much to ask, could you change that, please? Thanks, Francois |
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30th September 2012, 10:36 | #9 | Link | |
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John,
Quote:
It was intended against exacly the issue you describe, although I did not need an aircraft to produce it taking a shot while walking was sufficient. My intention is to publish that script in the wiki, but I am shy if its actual state is good enough for the public. Are you interested in testing it? Be warned. It is slow (approx. 1 fps with 640x480 on my core i5) and needs some ingredients like GRunt, GScript, MaskTools, RT_Stats, quad (thanks to the authors). I could say a lot more about how to deal with buildings (Freeze is better - less jello risk) vs. people or animals (MCompensate is better, can substitute moving persons/arms/legs). Freeze by more than two frames is risky because it can invert the original monotonic frame order, and make the clip look stuttering. EDIT: updated filter script Last edited by martin53; 2nd October 2012 at 18:31. Reason: Filter script updated |
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30th September 2012, 10:44 | #10 | Link |
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Dar1us,
you might want to test the Deshaker helper functions, especially the motion estimation improvement. See these posts. I never allow zoom, it always looked awful. |
30th September 2012, 12:23 | #11 | Link | |
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30th September 2012, 16:55 | #12 | Link |
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Of all the things you have done (and from your posts in several threads, it is clear that you have been busy), the automatic detection of the blurred frames is the most interesting. I'll be interested to see how that is accomplished.
As for testing, I have some old, low-res footage (i.e., VHS video) that I took from a plane flying at a few hundred feet in a circle around a target on a mountain ridge, and it is full of bumps from the thermals. The bad frames are definitely quite blurred. Finally, FWIW, here is what I was able to do with a similar program where I transferred motion picture film that was taken with a defective camera. This camera had a defective gear and did not advance the film all the way, but only sometimes, resulting in a "jump" every several frames. I couldn't figure out an accurately detection algorithm, so I manually marked each frame, and then used a script that took those marks and replaced the bad frames with a motion-estimated version, using the adjacent frames: http://www.youtube.com/watch?v=uzMFo...ECA2CB&index=2 And yes, I'd be interested in testing whatever you have developed. Last edited by johnmeyer; 30th September 2012 at 16:56. Reason: spelling error I didn't catch |
2nd October 2012, 18:41 | #13 | Link |
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John,
I downloaded your movie and tested with this script: Code:
<your source filter here, I converted flv->avi with XMediaRecode> crop(20,0,-326,0) FSubstitute(5,quad=false) FSubstitute found all bad frames and exchanged them. Because the bad frames also 'jump' downwards, FSubstitute also replaces them below their original position. Maybe a setting that prevents Y correction would make sense, because this is a typical damage. |
11th November 2012, 17:38 | #15 | Link |
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Though I still did not finish everything for a full release, I posted it in the forum in a new thread. I think it is worth being tested now.
EDIT 11/22/2012 John, your example above is now decently repaired with frame freeze or interpolation by your choice with the script. See mentioned thread. Last edited by martin53; 23rd November 2012 at 22:41. |
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