In this work, we propose analytical solution to non-frontal camera calibration in a generalized pupil-centric imaging framework. The decentering distortion is explicitly modelled as a sensor rotation with respect to the lens plane. The rotation parameters are then computed analytically along with other calibration parameters. The centre of radial distortion is then computationally obtained given the analytical solution. We also look at the radial alignment constraint(RAC) of Tsai and generalize it to a non-frontal setting proposing a generalized radial alignment constraint (gRAC). In the new setting, we derive analytical solution to a subset of calibration parameters and propose techniques to handle ambiguities in this setting. We also propose a focal stack calibration which uses a non-frontal image sensor to capture the focal stack and uses the blurring information in the focal stack to improve of traditional camera calibration techniques.

• A. Kumar and N. Ahuja, Generalized Pupil-Centric Imaging and Analytical Calibration for a Non-frontal Camera, Computer Vision and Pattern Recognition (CVPR), June 2014, Columbus, Ohio, US.
• A. Kumar and N. Ahuja, Generalized Radial Alignment Constraint for Camera Calibration, International Conference on Pattern Recognition (ICPR), August 2014, Stockholm, Sweden.
• A. Kumar and N. Ahuja, Non-frontal Camera Calibration using Focal Stack Imagery. International Conference on Pattern Recognition (ICPR), August 2014, Stockholm, Sweden.