Does camera have to be at same height

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    Does the 3D camera have to be at the same height as the projector. I’ve seen photos of system where it is not. What has to be done different as far as calibration if the camera is not at the same height?


    — greg


    No does not. It is just convenient that they are at similar heights for table construction.


    OK, thanks for you response.

    Yes, I agree that ease of construction is definitely a factor in setting the height of the camera.

    I re-read the instructions a little more carefully and I think I understand why Oliver recommends that the camera be located 40″ above the sand. The Kinect camera has a 90 degree field of view and the vertical resolution is roughly proportional to the height of the camera squared. The closer the camera is to the sand the better the resolution. In particular the better the vertical resolution is as it degrades quickly as the distance to the sand increases. Because of the 90 degree field of view of the camera and its 4:3 aspect ratio, with a sandbox that is 40″ x 30″ the camera will exactly cover the area of the sand when it is at a height of 40″.

    Oliver’s original instructions were based on using the discontinued projector model MX631ST with an adjustable throw ratio of .9 to 1/08. A throw ratio of 1 would require the projector to be at 40″ from the sand to project a 40″ wide image. The current model which is the closest to the 631ST is model MW632ST with an adjustable throw ratio of .72 to .87. By adjusting the optical zoom and the throw ratio the 632ST (according to the manual that came with the projector) will project an image size of 30″ x 40″ from a height of 36″ to 43″ from the sand. The BenQ manual says “All measurements are approximate and may vary from the actual sizes.” A little experimentation is required.

    If I understand this correctly,the camera needs to be at 40″ from the sand and with the MW632ST projector it needs to be at what ever convenient height between 36″ to 43″ that will just cover the sandbox. Placing them both at 40″ might work just fine.

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