What are the main references to the fish-eye camera model in OpenCV3.0.0dev?

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Hi Guys,

I am wrestling with the Fish-Eye Camera Model used in OpenCV 3.0.0.dev. I have read the documentation in this link several times, especially the "Detailed Description" part and formulas modelling fish-eye distortion. By now I have two concerns:

1. Based on the projection models listed here and their conceptual explanations in "Accuracy of Fish-Eye Lens Model" By Hughes, I can't figure out which projection model has been used in OpenCV implementation.

2. Since the description is so concise, I need to know the main reference papers used by OpenCV developers for implementing fish-eye namespace, so that I could be on the ball and get through more details.

P.S. I checked OpenCV 3.0.0-dev Documentation and did not find anything useful.

Thanks everyone for your help,

Kind Regards,

Masih