Working with depth

On and off for the last two days I have been looking into getting the depth data displayed to the user aswell as the RGB. This has proven to be a bit tricky. Firstly when I got OpenGL to display to depth data the image was really weird, black and white, overlapping and duplicated. There was definitely something going wrong somewhere, although I was using the exact same commands as for the RGB view and as the glview example supplied with libfreenect.
So I did a lot of playing and changed some of the individual OpenGL parameters one at a time to see if that made any difference. Then I found that to get some actual colour in the view and to get things looking a bit more fixed I should switch the Format parameter of glTexImage2D function to GL_RGBA.

I then did more playing to see why there was duplicating of the image. It seemed like it was showing one frame, then to the right of it, the previous frame and then underneath them there was about 2 of the same frame but with the occasional static messing it all up. It was very weird… It seemed like the image I was receiving from the library was bot actually 640×480 pixels but actually smaller. So I made a few changes to the interface of my program so I could change these values as the program was running to see what was the actual resolution of the input data.
It turns out that height of the image I was receiving was 320 pixels and the width was 480. This didn’t make any sense at all… And also it meant I was missing out on vital resolution that will be very important in my calculations later on.

So after a bit of thinking I thought that maybe there is something wrong with the library I am using and at the moment my OpenCV install doesn’t work so I cannot test the example program I have 😦 I’ll have to try and get this working tomorrow though.

Also another thing, if it is the library which is screwing up then I’ll have a look into making my own objective-c wrapper 🙂 this does mean wasting a load more time though…

And something else I’m wondering about is how do they get the different colours working in the glview example when the variable in mine is only 8 bits wide?? I think maybe the size of the variable I’m putting the depth textures in is a bit too small, smaller than what I’m getting in for the depth.

Let’s check what the actual resolution of the Kinect IR camera is, or at least the depth image that we get.

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