A scanner is programmed to extract a machine-readable identifier (e.g., encoded in watermark or barcode form) from an object, and transmit same to a remote computer (e.g., over the Internet). The remote computer responds with supplemental information or e-commerce opportunities relating to the scanned object. This information may be presented on an LCD display built-in to the scanner. In some embodiments, auxiliary CCD sensors are provided in addition to the scanner's usual image sensor. These auxiliary sensors can be employed for various purposes, including identifying surface texture characteristics so that corresponding filtering/processing of scan data can be performed; detecting affine transformations of the object being imaged so appropriate compensations can be applied, etc., etc.