Affine Structure from Translational Motion with Varying and Unknown Focal Length

In this paper a method for obtaining affine structure from an image sequence taken by a translating camera with varying and unknown focal length is presented. A general geometric constraint, expressed using the camera matrices, is derived and this constraint is used in a least squares solution of the problem. The proposed algorithm extends the previous result of affine structure recovery from an image sequence with a translating camera with constant intrinsic parameters to the case with a camera with varying and unknown focal length and otherwise known intrinsic parameters. The noise sensitivity of the method is evaluated in simulated experiments.