Hi Mohit,
The function pointsToWorld is under a class named cameraParameters. You can refer to the code provided in the class to understand the mathematics involved behind converting co-ordinates in an image to world co-ordinates. You can execute the following command to see the class definition --
>> edit cameraParameters.m
Additionally, the function can also be accessed from MATLAB Command Prompt by executing the following command -
>> edit cameraParameters.pointsToWorld
Regards.
