### initundistortrectifymap line 103 and 137 what is going on?

Hi,

I'm having trouble understanding a line in the original source code of the function initUndistortRectifyMap(..). In the corresponding docs this part doesn't seem to be mentioned.

The code is on line 103 and 137 of the following undistort.cpp function:

link text

It appears to be taking the ~~inverse ~~product of the camera intrinsic matrix A and multiplying it with the rotation. ~~Finally it ~~It then takes the inverses ~~the product and ~~(all on line 103). This is then used on line 137 ~~extracts ~~when bits are extracted out ~~some random bits. ~~from the result on line 103. The results I get when using this code are excellent but I just can't understand it or tie it into the documentation at:

link text

In particular I don't see how the first three lines of equations in the doc corresspond to the inverse of the cam matrix A and the rotation matrix?

Can some clever person put me right or point me at a doc that just explains that bit?
Thanks