Finding a camera for Eideticker

[ For more information on the Eideticker software I’m referring to, see this entry ]

Ok, so as I mentioned last time I’ve been looking into making Eideticker work for devices without native HDMI output by capturing their output with some kind of camera. So far I’ve tried four different DSLRs for this task, which have all been inadequate for different reasons. I was originally just going to write an email about this to a few concerned parties, but then figured I may as well structure it into a blog post. Maybe someone will find it useful (or better yet, have some ideas.)

Elmo MO-1

This is the device I mentioned last time. Easy to set up, plays nicely with the Decklink capture card we’re using for Eideticker. It seemed almost perfect, except for that:

  1. The image quality is really bad (beaten even by $200 standard digital camera). Tons of noise, picture quality really bad. Not *necessarily* a deal breaker, but it still sucks.
  2. More importantly, there seems to be no way of turning off the auto white balance adjustment. This makes automated image analysis impossible if the picture changes, as is highlighted in this video:

Canon Rebel T4i

This is the first camera that was recommended to me at the camera shop I’ve been going to. It does have an HDMI output signal, but it’s not “clean”. This blog post explains the details better than I could. Next.

Nikon D600

Supposedly does native clean 720p output, but unfortunately the output is in a “box” so isn’t recognized by the Decklink cards that we’re using (which insist on a full 1280×720 HDMI signal to work). Next.

Nikon D800

It is possible to configure this one to not put a box around the output, so the Decklink card does recognize it. Except that the camera shuts off the HDMI signal whenever the input parameters change on the card or the signal input is turned on, which essentially makes it useless for Eideticker (this happens every time we start the Eideticker harness). Quite a shame, as the HDMI signal is quite nice otherwise.

To be clear, with the exception of the Elmo all the devices above seem like fine cameras, and should more than do for manual captures of B2G or Android phones (which is something we probably want to do anyway). But for Eideticker, we need something that works in automation, and none of the above fit the bill. I guess I could explore using a “real” video camera as opposed to a DSLR acting like one, though I suspect I might run into some of the same sorts of issues depending on how the HDMI output of those devices behaves.

Part of me wonders whether a custom solution wouldn’t work better. How complicated could it be to construct your own digital camera anyway? 😉 Hook up a fancy camera sensor to a pandaboard, get it to output through the HDMI port, and then we’re set? Or better yet, maybe just get a fancy webcam like the Playstation Eye and hook it up directly to a computer? That would eliminate the need for our expensive video capture card setup altogether.

4 thoughts on “Finding a camera for Eideticker”

  1. It doesn’t look like the playstation eye can capture at a setting the Decklink card can comprehend, or do intend to just capture video directly off the camera and then sort the frames out yourself in code? Is there an API to capture that video coming in? I’m not sure you do that without the HDMI capture card and how that would work if the signal coming out of the camera is not in a format the card can understand.

  2. Yeah, the idea would be to just capture video directly via the Eye’s USB interface (apparently you can treat it like any other linux webcam). No HDMI or decklink card involved.

  3. The GoPro Hearo 2 (I have one) has a clean output in 1080p The problem is that it is a very wide angle, so I’m not sure how suited.

  4. Have you seen the upcoming camera module for the Raspberry Pi? According to [1], “Video quality from the 5MP camera is quite good, and it’s capable of capturing full 1080p resolution at a crisp 30 frames per second.” I imagine you can then relay the data through the Raspberry Pi’s HDMI output or other means. You might have more control over the camera too since it’s meant to be hacked.


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