Full-res silent captures

Use this forum to request new features or suggest modifications to existing features
Post Reply
Bastet
Posts: 3
Joined: Sun Apr 02, 2017 4:05 am

Full-res silent captures

Post by Bastet » Sun Apr 02, 2017 5:06 am

My project is currently using a Canon Rebel T6s to capture 8mm film frame by frame. I have a specially modified 8mm film projector to advance a single frame under Arduino and PC control.

I have two issues that needs to be addressed.

1 - Shutter Actuation - A 50' roll of 8mm film has ~4000 frames and I have several dozen rolls so using the shutter for each frame capture will significantly reduce the shutter's lifespan (on the order of ~50k to ~100k actuations.)
2 - Resolution - I can capture a Live View stream without using the shutter but it's resolution is greatly reduce (not full sensor resolution.)

My camera, as well as several other Canon models, can also stream 5x Live View (which is apparently a 1:1 sensor pixel image, but only a small portion of the full sensor, much like a digital zoom.) Would it be possible to capture several 5x Live View streamed images from different parts of the sensor and stitch them together to produce a full-res image (24M pixel image) using only the Live View stream?

The images I plan to capture will be under controlled lighting conditions so I expect the final stitched image to be virtually seamless if aligned correctly.

I'm sure full-res time lapse images without shutter actuation would be a great addition to this project.

Thanks for your thoughs and consideration.

Full-res silent captures

Advertisment
 

admin
Site Admin
Posts: 90
Joined: Tue Sep 15, 2015 8:33 pm

Re: Full-res silent captures

Post by admin » Sun Apr 02, 2017 10:29 pm

The quality of the live view it is very low, even with zoom and stitching the image still will be low quality, not wort the time, a single image will required about 16-20 "captures" and isn't guaranty the stitching will be always perfect.
I think it is more easy way to use a camera with electronic shutter like p&s camera or a high-end dslr camera

Bastet
Posts: 3
Joined: Sun Apr 02, 2017 4:05 am

Re: Full-res silent captures

Post by Bastet » Mon Apr 03, 2017 8:10 pm

The sensor on the Canon T6s is 6000 by 4000 (24m pixels, ~9mb JPEG). Live View sends back 960 by 640 (614k pixels, ~220k JPEG). It would require an even 36 Live View samples (cropping about 240 pixels horizontal and 160 vertical pixels, final image of 5760 by 3840.)

The 5x zoom during Live View samples only a 960 by 640 portion of the sensor so all sensor pixels are available, there are no visible zooming artifacts. You would have to move the 5x zoom location for every Live View sample, 36 times.

A stitch of 36 (6 by 6) Live View captures of ~220k images would produce an ~8mb image. Hardly low quality. If the zoom location is properly specified, aligning the images should be visibly seamless provided the camera or your scene is very steady .

It's like those giga-pixel images you see on the internet. Of course it's not a real-time image. It will take some time to record 36 images and stitch them.

For my needs, and I'm sure for others, something like this would be perfect instead of just replacing my hardware to achieve the same results. It would bring silent full-res time lapse photography, with limitations of course, to many cameras, Canon at least, that currently do not provide such an option.

Edit: I've experimented a bit and discovered a few errors. Live View in "5x" mode returns a 1200 by 800 image, a fifth in both horizontal and vertical full sensor resolution, so only 25 Live View captures (5x5) need to be stitched. The Live View area can be selected, or moved around, to grab the entire sensor image for a full resolution 6000 by 4000 final image. Sounds trivial to implement. As a UI, a simple checkbox could select to capture normally (currently with shutter actuation) or use this Live View method (without) to capture images.

Bastet
Posts: 3
Joined: Sun Apr 02, 2017 4:05 am

Re: Full-res silent captures

Post by Bastet » Sun Apr 09, 2017 10:20 pm

Update:

I've created a proof of concept using a modified version of your CameraControlDevices solution (Example.) Here is a low quality comparison of the Live View stitch vs a shutter capture (6000x4000 image.) http://imgur.com/a/8G5KF

Due to the way my Canon T6s selects 5x zoom areas in live view (weird grid system that doesn't line up logically) the best use of 25 live view captures (5x5) exclude about 2% pixels around the edges. Only the top 6 pixels of the sensor are inaccessible. The full image of 6000x3994 is available but requires 7 more captures (6x6 or 32 live view captures.) I figured a 2% border is a nice compromise to faster capture times and for my needs, completely acceptable (overall loss of 240x196 pixels distributed around the edge.)

Since live view is used, the camera does not process the image, so there is no in camera lens correction or imaging processing. The image is also darker. There is some visible color aberrations and probably vignetting as well. These things could be fixed in post.

As for quality of the stitched image, the animated gif doesn't do it justice. 95% as good as an original. Program wise, multiple live view captures can also be stacked to reduce sensor noise or HDR captures all without using the physical shutter. You are, after all, limited to simulated shutter speeds and a static scene. All this with a few dozen lines of code.

As far as I researched, nobody does captures this way, except Magic Lantern but it's not available for my Canon T6s yet, maybe ever.

I'll be able to finish up the modified code to suit my original objective and needs, if you're interested in implementing this feature, drop me a note and I'll be happy to share my findings.

admin
Site Admin
Posts: 90
Joined: Tue Sep 15, 2015 8:33 pm

Re: Full-res silent captures

Post by admin » Mon Apr 10, 2017 9:23 pm

Yes any contribution is welcomed. If you have any code please share it

ondrejdee
Posts: 1
Joined: Fri Jun 16, 2017 2:47 pm

Re: Full-res silent captures

Post by ondrejdee » Fri Jun 16, 2017 2:55 pm

Magic Lantern has a feature called "Silent Picture" which enables you to take a full resolution picture without shutter actuation:

http://www.magiclantern.fm/forum/index. ... ic=12523.0

However, I don't see whether some sort of integration of Magic Lantern and digicamcontrol is, at all, possible.

SnurrDass
Posts: 1
Joined: Sun May 06, 2018 7:53 pm

Re: Full-res silent captures

Post by SnurrDass » Sun May 06, 2018 7:59 pm

Hey
Did you get any solution to your problem?
i'm in the same situation, and need a silent capture and not wear out my DSLR cam.

I see that a new fucktion in the new 2.0.76.1 have a option on drive mode thats say Silent LS Continuous but i cant make i work.
i have a Canon EOS 500D atm

snakkob
Posts: 1
Joined: Thu Aug 23, 2018 3:54 pm

Re: Full-res silent captures

Post by snakkob » Thu Aug 23, 2018 4:07 pm

Hi,

Is it possible to get some kind of Lens Correction? We have an installation where we use the Nikon D3400 and a 18-55VR Lens, and we use the camera mounted in the ceiling to take photos and turn these into templates, but we can't correct the templates evenly as a A4 is not proportional to a A0.

A paid solution matching our need could be an option.

Rgs.
Jakob Skov

Duka Istvan
Posts: 614
Joined: Sat Oct 03, 2015 7:57 pm

Re: Full-res silent captures

Post by Duka Istvan » Thu Aug 23, 2018 4:38 pm

Please send a email to admin@digicamcontrol.com describe again your issue and attache some example images for better understanding of the problem


Post Reply

Who is online

Users browsing this forum: Dutch Brush and 1 guest