The commercial imaging marketplace offers scanning equipment with a variety of throughput speeds, automated operator features, and acquisition costs. Actual elapsed times for scanning and displaying the images varies based on several factors including the inherent performance of the specific scanning unit, physical dimensions of the documents, and scan resolution selected. These factors contribute to desktop-class scanner production rates of between 2 and 20 documents per minute. When equipped with special image-enhancement capabilities, desktop scanners are also effective for scanning low-contrast documents, which are difficult to read. These scanners also function effectively for rescanning poor-quality images rejected during routine image quality-control inspections.
For larger document conversion applications, higher performance scanners that employ heavy-duty mechanized document transports and multiple scanning charge-coupled device (CCD) arrays are available. This equipment offers throughput rates ranging from approximately 40 to 120 or more pages per minute. Depending on the specific unit, these scanners may capture two sides of each document on one pass, improving productivity through reduced paper handling. Specialized scanners are also available for capturing larger documents such as maps and engineering drawings.