Computer programs for use in processing image data captured by a sensor responsive to a physical object in view of the sensor, comparing the processed data to previously stored image data, and reporting a similarity metric as between the processed data and the previously stored data, to aid in assessing a relationship between the physical object and a second object that was used to form the previously stored image data, wherein the first and second objects are documents such as driver licenses, passports, checks, bank notes and other negotiable instruments; Computer programs for use in processing image data captured by a sensor responsive to a physical object in view of the sensor, comparing the processed data to previously stored image data, and reporting a similarity metric as between the processed data and the previously stored data, to aid in assessing a relationship between the physical object and a second object that was used to form the previously stored image data, wherein the first and second objects are consumer goods such as purses, watches, luggage, jewelry, apparel, shoes, home decoration items, and eyeglass frames; Computer programs for use in processing image data captured by a sensor responsive to a physical object in view of the sensor, comparing the processed data to previously stored image data, and reporting a similarity metric as between the processed data and the previously stored data, to aid in assessing a relationship between the physical object and a second object that was used to form the previously stored image data, wherein the first and second objects are industrial parts such as aircraft parts, motor vehicle parts, vessel parts, engine parts; Computer programs for use in processing image data captured by a sensor responsive to a physical object in view of the sensor, comparing the processed data to previously stored image data, and reporting a similarity metric as between the processed data and the previously stored data, to aid in assessing a relationship between the physical object and a second object that was used to form the previously stored image data, wherein the first and second objects are electronic parts and portable electronic devices; Computer programs for use in processing image data captured by a sensor responsive to a physical object in view of the sensor, comparing the processed data to previously stored image data, and reporting a similarity metric as between the processed data and the previously stored data, to aid in assessing a relationship between the physical object and a second object that was used to form the previously stored image data, wherein the first and second objects are containers for shipping pharmaceuticals; Computer programs for use in processing image data captured by a sensor responsive to a physical object in view of the sensor, comparing the processed data to previously stored image data, and reporting a similarity metric as between the processed data and the previously stored data, to aid in assessing a relationship between the physical object and a second object that was used to form the previously stored image data, wherein the first and second objects are pharmaceuticals; Computer programs for use in tracking products through a supply chain; Computer programs for use in tracking parcels through a delivery chain; Computer programs for use in tracking luggage from a point of origin to a destination location