Realtime HDR Video

Adam Adorno · September 10, 2009

A couple of colleagues of mine and myself are so close to producing realtime HDR video. We have done samples by combining 3 different 4-second long videos at 3 different exposures off an XHA1, and the results are unbelievable.

So, here's my dilemma...

We are looking for two possible pieces of the puzzle. Either, a small mirror/prism rig where 3 A1's can connect to it and film 3 versions of the same EXACT image, OR, find a program that has the ability to take 3 slightly offset images/videos and warp them to one of the videos so they all look identical. I imagine the computer taking the features of one image, and then compares it to another image that's slightly different (taken from another camera 2 inches to the side of the other), and warp the image to the details and features of another. I've looked into stereoscopic workflows and such, but it only gets me so far, since stereoscopic video is trying to produce two slightly offset images instead of 2 identical images. Again, I'm dealing with 3 images that I'm trying to make identical, even though the cameras will be inches apart.

Any ideas? We have a workflow figured out and everything, but we are just missing that last piece of the puzzle. Once I figure out this roadblock, I've done it. Real-time HDR Video. Finally.

This is what I've produced so far.

http://img269.imageshack.us/i/20191350.jpg/

Those 2 cars you see that look ghosted are actually the same car. Each exposure that was combined was a different moment in time, since this test was done with a single camera. I have yet to produce a great quality image from 3 cameras, obviously, that's what this post is for.

Scott Fritzshall · September 10, 2009

You're going to have better luck with a camera rig than by warping your images. The rig you're looking for is something similar to the "Crazy Horse" rig that was used in 300. You can also look at Ocula from The Foundry as far as stereo image tools go, but I don't know if it will fit your needs and it's going to be really processing-intensive and it's probably never going to look like what you want it to- at least not automatically. Also make sure your cameras are genlocked when you shoot.

Peter Milanov · September 15, 2009

I don´t want to rain on your parade, but the last piece of the puzzle is a very large one compared to what you have done so far. Bracketed exposures has been used for a long time, I remember doing it for some low budget commercials for local television back in the early nineties, combining the images is not the hard part. What you have left to do is basicly what James Cameron did for Avatar but adding yet another camera (and of course have them perfectly aligned at all times instead of the 3-d setup used there).

I would imagine an HDR camera would have to be more like a 3ccd camera but with 3 cmos chips after the beamsplitter. That would make a usefull HDR camera with only one lens.

Saul Rodgar · September 15, 2009

It would make more sense to do it all within one camera, if infinitely more complex.

Still, I don't mean to say the OP shouldn't try to build that 3 camera rig, however unwieldy and cumbersome it may turn out to be. Certainly, the exact alignment of such a rig would an absolute must.

Also, the cameras may have to be so close together that some controls may be inaccessible after mounting them on the rig. This set up may be best suited for cameras that can be controlled remotely / or with paintboxes. I forget if Canon has a software to control cameras through PCs.

Edited September 15, 2009 by Saul Rodgar