Fundamental parallax error when blending images from multiple cameras

Written by Paul Bourke
February 2017

The acquisition of multiple photographs which are then stitched/blended together to form a composite image is a well known technique. The most common applications are panoramic photography and image mosaic/tiling. Whether standard lenses or fisheye lenses, those who work in this area take some care in aligning the poorly named "nodal" point of the camera/lens system, essentially combining multiple camera frustums into a single wider angle view frustum. Otherwise, for two or more cameras located at different physical locations a perfect stitch/blend in fundamentally impossible, this is not for want of trying, it simply cannot be achieved perfectly. The following diagram is intended to illustrate why this is so, why one can stitch/blend at any one depth but not all depths at once.