World's First Full HDR Video System Unveiled

Zothecula writes "Anyone who regularly uses a video camera will know that the devices do not see the world the way we do. The human visual system can perceive a scene that contains both bright highlights and dark shadows, yet is able to process that information in such a way that it can simultaneously expose for both lighting extremes – up to a point, at least. Video cameras, however, have just one f-stop to work with at any one time, and so must make compromises. Now, however, researchers from the UK's University of Warwick claim to have the solution to such problems, in the form of the world's first full High Dynamic Range (HDR) video system."

Comments

More interesting than 3D?

[Anonymous Coward]

Personally, I think the HDR screen described, with HDR videos, would be more interesting and immediately useful than the ever-so-commonly-advertised but ever-so-rarely-purchased "3D" screens.

Not so fast there son

[Anonymous Coward]

Didn't a pair of guys do this last year using a pair of DSLR's and a beam splitter?

Also ,unless someone is building a HDR display this is all pretty academic, HDR images have to have their range compressed and then tone mapped in order to be displayed via conventional means, this is normally terribly unsubtle and results in an image that looks not entirely unlike it was rendered using 3d modelling. If we are going to see another big shift in display (read: TV) technology in the next decade I would much rather we moved away from the sRGB / YUV colour space than started fucking about with HDR content, what's the point of trying to take advantage of our eyes exposure latitude if we can only render 1/3 of colours?

Re:Not so fast there son

[MightyMait]

If you read the article, the author mentions both the folks in SF who did HDR video previously as well as the fact that the Warwick team have indeed developed a new HDR display for their system.

Also mentioned is that the new system generates 42GB/minute of data to capture images with 20 exposures per frame. My backup nightmare just grew large fangs!

So how about some decent framerate?

[NeutronCowboy]

I mean, we have 1080p 3D stereovision with full-micron surround color effects, and yet, movies still stutter like mad on a fast pan because that damn 24 fps capture rate just can't keep up. Is it really so much harder to capture 60 fps and encode than it is to do a working 3D effect? I'd pay more for movies that have reliable framerates in the 60 Hz range than I would for 3D.

Re:So how about some decent framerate?

[Doogie5526]

Roger Ebert asked the same thing (on page 4)
http://www.newsweek.com/2010/04/30/why-i-hate-3-d-and-you-should-too.html

I think there's a couple reasons. The first, and probably most significant, is nostalgia by film makers. They love the motion blur of 24fps. It helps evoke the "feeling" of film. Every film student I know either wants to shoot or convert their footage to 24fps. There is a noticeable difference. When you start increasing the resolution and frame rate, you lose motion blur and it starts to look like home video or video games (when generally don't compute motion blur at all).

Another big issue is the amount of light. When you have more frames in a second, each frame has less light to suck up. It's a big issue with high-speed film. Having sensors that are more light-sensitive is a fairly recent thing (combined with advanced noise reduction) and will continuously get better.

The stuttering is something cinematographers keep in mind when shooting (or at least, they should). I read an article about shooting imax and they said the biggest problem was the stuttering. They're also using 24fps, but the screens are much larger. When you pan, the object could jump 2 to 3 feet per frame. They intentionally had slower pans to compensate. You noticing this is probably a side-effect of larger theatrical screen and larger tvs at home.

Re:Cool stuff

[Doogie5526]

I find it kind of funny that HDR means the opposite thing in photography versus video games
http://img194.imageshack.us/img194/7391/1244894383293.jpg (pulled from some old digg post)

Traditionally games render the world and keep it between 0 and 1 (zero being black/completely dark and 1 being white). HDR is computing values above and below and clipping so things that are blown out (like reflections and highlights) are super white. I think it was an update to Half Life 2 that first did this in a commercial game.

In photography, they take multiple exposures and stick them in to an HDR image. Then, they use tone mapping to convert it to an 8-bit visible image. Tone-mapped images are generally called HDR, even though that's a misnomer.

Re:Modern cameras have _much_ more than one f-stop

[muridae]

The summary is just plain wrong, and the article may be as well. First, there seems to be some massive confusion between f-stops and dynamic range 'stops'. An f-stop is your aperture setting, and is part of the control that determines how much light gets into the camera. If I go out and desire to take an HDR picture of something, the f-stop is the last control I will use in setting each exposure. The f-stop has the side effect of changing the depth of focus, thats covered in photography 101. If you change that in a set of pictures, some things will be in focus in one frame, while out of focus in others. It doesn't look that nice once post processed.

On the other hand, a dynamic range stop is just notation for double the amount of light. If someone said "That film has about 9 stops of resolution" you would know that physically the brightest area on a picture would have 2^9 times as much photonic flux. Or you would be more camera focused, and know that the film would only record detail in the 4.5 stops above, and 4.5 stops below what ever you set the exposure for. An object 5 stops brighter than what you were focused at would be a washed out blur, and something 5 stops darker would be total shadow. A quick run through google suggests that Kodachrome, the legendary film, could record only about 8 stops dynamic range. The human eye can pick up something closer to 24 stops. GP's Red camera records 11.3 stops. Some people will claim that a digital camera gets as many stops as bytes, but that is only with the analog to digital conversion is logarithmic, and so is the display it is shown on. Mine runs about 7 stops, depending on other settings.

So, what's that got to do with this camera? I suspect what the article meant to say is that the camera captures 20 stops of data at 30fps. Better than the Red, better than almost any film in existence. It is doing the same thing in a single shot that other cameras do in several. All that will mean is less blur in HDR video, since subjects won't move irregularly between exposures. One would still have to tone-map the output down to a range that it can be displayed for printing, projection, or dvd.

Re:Cool stuff

[The13thSin]

I would like to correct a mistake prevalent here and in the news summary: common camera's do NOT get 1 (or 2) stops of light information (the difference between black and white). In fact, camera's like the Canon 7D have about 11 stops of dynamic range [source] and professional video camera's like the Red One have about 13 1/2 stops of difference between black and white [source]. Still, as X stops means 2^X times the light difference, going from 13 1/2 to 20 stops is a pretty huge deal.

Another misconception: the amount of bits per channel only indicates precision, not dynamic range. Of course, when the researchers in the article created a 20 stops camera, they needed much better precision to get similar quality in the same range as the current camera's, which leads to the quoted 42 GB per minute uncompressed video stream.

(Please note: DSLR camera's like the Canon 7D can detect and save more dynamic range than is apparent from the JPG's they create and the extra information is saved in the RAW file, which allows you to change exposure settings at least 1 stop in post processing without (noticeable) drop in quality.)