For semiconductor memory garbage collection, an identification module identifies a garbage collection time window for at least one block of a flash memory array. A buffer data control structure is modified to include a flags array that tracks various status flags for both a current and a next consistency point. Management of appointments and tasks from a central database promotes collaboration among users, simplifies sharing of schedule information among users, and provides context for data entry. A purchase pattern of the website is retrieved such as from a database of stored purchase patterns that have been determined for various websites. Three-dimensional targets, in particular, enable endoscopic calibration using a single image to reduce the calibration process complexity, calibration time and chance of error as well as allow the efficient calibration of cameras at different focus positions. The enhancement film resides between the light source and the carbon layer.