By : Holanddez1′

Advance

Gotta try

It makes a high resolution image from the series of lower resolution images, nearly equivalent to a single longer exposure. This is actually a really clever hack, because it gets around the problem of needing to read the pixels extremely quickly. The Casio EX-FC100 is a 9 megapixel camera that is able to take 1,000 fps video, but it does it at about 60×200 pixels with relatively poor quality.

@kirov
You are right of course, you don’t get something for nothing.
The way this works is to capture the image four successive times, on four different sets of pixels that are evenly mixed and spread out across the sensor area. Micro mirrors are used to the light to these pixels.
After the 4 images are taken the whole ccd will have been exposed, hence the full resolution image. Also you will have 4 distinct time periods when different images were captured, although with 1/4 of the resolution for each frame.

So far so good, the catch is of course the 4 time periods which make up a single image must be fast if you wish to avoid image blur etc. This means that only a small quantity of light will reach each pixel (1/4 of usual) so the sensor must be much more sensitive, and therefore expensive (or await newer tech…)

This is obviously an interesting idea but my cell camera is crap enough without restricting the light even more…

some hobbyist supplier could make a lot of friends with a (relatively) cheap DMD, that doesn’t need an FPGA to control it… (not a lot of people might be willing to dismantle a perfectly good projector just to get the DMD and video input -> control board for projects).

@pascal

TI recently updated their low-end pico projector kit to allow direct manipulation of the DMD binary patterns.

It’s only VGA resolution, but it can do 1400-2400 fps with binary patterns and is (only) $350, as opposed to the $5000+ they charge for the high-end dev board. Considering the time and expense required to hack up an FPGA interface, it’s a pretty good deal. (I plan to use one for a high-speed structured light scanner)

http://focus.ti.com/analog/docs/memsmidlevel.tsp?sectionId=622&tabId=2447

One big problem with this approach is that all data must be captured RAW with no compression (since compression would annihilate all the motion data encoded in the adjacent pixels). And the idea that your “still” image would be of comparable quality to a regular camera is absurd because as Rod noted each pixel will only be receiving a fraction of the light available.

So I don’t see the advantage… even if implemented directly on CCD to accommodate high speed video capture, you would have some unwanted jitter because pixels would be “moving” over time.

Capturing the images in RAW isn’t a problem or a bad thing. It’s a complete non-issue. Hell, if you are trying to make measurements you’d rather have the RAW image anyhow (or some loss-less compression).

Or from 2004 (using webcams): http://graphics.stanford.edu/papers/highspeedarray/

I was thinking of trying light field photography on a single DLSR CMOS sensor (since it scans anyway) for high speed.

See: http://graphics.stanford.edu/papers/lfcamera/

“This method adds a digital micromirror device in line with the camera lens”

that kind of defeats the tight wadity of the project.

the whole idea of using a cheap camera (in my view) is to save money from having to pay thousands for a high speed camera and possibly even having the purchase get hung up in the red tape of export restrictions verification ( high speed along with thermal cameras are one of the many controlled devices that is illegal to export and a criminal background check may be performed)

@razor386
Nope, that’s just the rolling shutter effect.

@Chris
You’re underestimating just how expensive high-speed cameras are. Compare a few hundred for the CCD plus a few hundred for the DMD (say, 1000 total), versus several tens of thousands for a high-speed camera.

Rolling shutter? The mirror is flipped up and the sensor is exposed the entire time I believe or are you talking about something different?

@intepid
How are you with car analogies? It sounds kind of like tuning your car suspension for drifting instead of doing the quarter mile.

You’re simply optimizing performance for a particular kind of behaviour (normally a very expensive kind of behaviour). It’s easy, and cheap to get high pixel count ccds. Wal-Mart has 12 mega-pixel cameras around $150 usd. The same cannot be said for high-speed sensors.

This is a great hack, and could allow hobbyist researchers access to high-speed video data at low cost.

@tantris:that will not work, because your rotating mirror can’t switch between den cameras in a short time and will “smear” the image over the sensors.

I didn’t make my point clearly, which was: if you access a smaller portion of the sensor, you can access it at a much higher speed than full frame captures. This is a purely electronic solution using existing technology and is how high speed cameras have worked for decades.

tbh this ‘amazing’ idea works on the exact same principles as interlacing which is used as standard in video already and is something that we are desperately trying to get rid of.

Well done for reinventing the wheel

I’m a professional photographer. I got tired of dragging my D3,D200 or other large cameras around, and worrying about it getting damaged. I decided to buy a camera just for fun that could fit in my purse and I wouldn’t have a heart attack if it broke. Well I didn’t hold that high of expectations of the camera, but after getting it, I’ve had a lot of fun with it. Not the most amazing pictures come from it (I am used to very high quality pictures), but they are good enough shots of my family. It’s easy to use, really easy to set, FAST, and good low light. You don’t always need the flash. It’s very small, and can fit easily in my purse (that are all quiet small purses actually). This is a perfect camera if you just want some fun shots that are clear, and you want an easy to use fast camera. This is NOT good for “professional” type shots (why do people write reviews of these cameras and get all down on them for not being professional grade cameras? They never claim to be!).

I would hope to be back tracking. Thanks for the great write-up.