We have shown how it is possible to obtain high resolution images of whole documents using standard CCD cameras. The process is robust, quick and fully automated, and the quality of the resulting images is sufficient for OCR or printing (with some post-processing [ 12 ]). The overall system provides a flexible, convenient alternative to the flat-bed scanner. As it stands the system relies on the document containing predominantly text, though the segmentation stage could be developed to cope with photographs and illustrations.
Possible avenues of future work suggest further significant applications. The system could be extended to cope with curved surfaces, so that bound volumes could be scanned at the desktop with a hand-held camera. At the moment only specialist libraries are equipped with the dedicated optical hardware required to scan large, perhaps fragile volumes without contact or distortion. Another possible extension concerns super-resolution . The system currently constructs the high resolution images using the same size pixels as those in the anchor image. Super-resolution techniques [ 5 ] could be exploited to reconstruct the final mosaic on a finer grid, providing further resolution enhancement.
A.H. Gee