As I understand the left and the right IR cameras are pinhole box cameras with no distortions, however the depth frame returned appears to be distorted,
I need to understand this to better calibrate my R200 camera, as I need to calibrate it for a project.
Have you tried the R200's calibration app?
https://downloadcenter.intel.com/download/24958/Intel-RealSense-Camera-Calibrator-for-Windows-?produ... Download Intel® RealSense™ Camera Calibrator for Windows*
Please post the resulting picture so we can review it. If it's distorted, you can use the Camera Calibrator tool that @MartyG suggested. You can also take a look at this post /message/461408# 461408 https://communities.intel.com/message/461408# 461408 which also discuss distortions with the camera. You can find useful information here.
Keep us updated on your progress.