### Triangulate Points from Stereo Image

Hello guys,

I hope someone can help me with my problem :)

**That's my approach**

I have two cameras and now I want to calculate the 3D coordinates of an object. For this, I calibrate the cameras individually and then I use stereoCalibrate.

Now I have the intrinsic and extrinsic parameters and would like to triangulate.
To do that, I create the projection Matrices like this.

Basically one camera I can keep as P1= K1 [I|0] (identity rotation and 0 translation), and the other camera P2= K2*[R|t] (rotation and translation between the cameras from stereoCalibrate())

These matrices I hand over to the triangulate function (http://www.morethantechnical.com/2012/01/04/simple-triangulation-with-opencv-from-harley-zisserman-w-code/)

**To test the triangulation**

Checkerboard: 9x6 and 12 mm per square

I use the reference checkerboard images because the depth should be constant but i have depth "linear".
The x and y coordinates are accurate over the entire distance to 0.2mm.

The picture shows the values for the first two ~~rows~~rows. As you can see the depth is strange

Anyone know where is my problem?
Thanks.