So, I’m in the middle of reading every paper and patent related to Kinect, but in the meantime, I want to do something fun. Let’s look at the Kinect projector output.
The Kinect projector uses speckle to create this dot pattern. I will make an entire post about speckle, but in this case the IR laser is shining through a micro-patterned plastic lens. The resulting speckle pattern is “in focus” over a very large distance — tens of feet. For fun, I decided to place a book in the beam and look at just how it changed the pattern:
Here is the difference between those frames; the shift in the dots is immediately apparent.
Well, that was semi-informative. Interestingly, all the patents and papers related to the Kinect talk about creating the speckle dot pattern using a plain diffuser. While I’m going to demonstrate that in another post, this is NOT a random diffuser. In fact, the Kinect pattern repeats itself:
Here’s an animation of the different repeating elements laid on top of each other:
It’s not yet clear to me, however, if the repetition is actually being used by the Kinect, or if it is an artifact of micro-lithography/the diffuser printing process.