Does Kinect Infrared View Have an offset with the Kinect Depth View

Question

I am working on a Kinect project using the infrared view and depth view. In the infrared view, using CVBlob library, I am able to extract some 2D points of interest. I want

Answer 1

Depth and Color streams are not taken from the same point so they do not correspond to each other perfectly. Also they FOV (field of view) is different.

1. cameras

   • IR/Depth FOV 58.5° x 45.6°
   • Color FOV 62.0° x 48.6°
   • distance between cameras 25mm

2. my corrections for 640x480 resolution for both streams

   if (valid depth)
    {
    ax=(((x+10-xs2)*241)>>8)+xs2;
    ay=(((y+30-ys2)*240)>>8)+ys2;
    }
   

   • x,y are in coordinates in depth image
   • ax,ay are out coordinates in color image
   • xs,ys = 640,480
   • xs2,ys2 = 320,240

   as you can see my kinect has also y-offset which is weird (even bigger then x-offset). My conversion works well on ranges up to 2 m I did not measure it further but it should work even then

3. do not forget to correct space coordinates from depth and depth image coordinates

   pz=0.8+(float(rawdepth-6576)*0.00012115165336374002280501710376283);
   px=-sin(58.5*deg*float(x-xs2)/float(xs))*pz;
   py=+sin(45.6*deg*float(y-ys2)/float(ys))*pz;
   pz=-pz;
   

   • where px,py,pz is point coordinate in [m] in space relative to kinect

   I use coordinate system for camera with opposite Z direction therefore the negation of sign

PS. I have old model 1414 so newer models have probably different calibration parameters