Yes, but the headers shouldn't either (everyone using C++ sees the header names). Easily fixed.Only the files have that name. Functions don't have the prefix.
As basic good coding guidelines, such things should be separate functions then with descriptive names. You can always share implementation internally, but having the meanings of arguments change based on other arguments is even worse than having generic names on the arguments.- calling the arguments to add_noise op1 and op2 is horrible. They should have descriptive names.add_noise uses different functions with different meanings for op1 and op2, thus they can't be described properly. They are 2 arguments.
It is probably pretty easy to compute the desired euler angles from a quaternion (but I haven't done so, so I am not entirely sure). If it is, you wouldn't have to change project/project is a hard function to develop, and the math behind it is far better implemented with a given convention. Hence the definition.