Techniques for capturing long document images and generating composite images therefrom include: detecting a document depicted in image data; tracking a position of the detected document within the image data; selecting a plurality of images, wherein the selection is based at least in part on the tracked position of the detected document; and generating a composite image based on at least one of the selected plurality of images. The tracking and selection are optionally but preferably based in whole or in part on motion vectors estimated at least partially based on analyzing image data such as test and reference frames within the captured video data/images. Corresponding systems and computer program products are also disclosed.