Development of Software for Calibration and Testing of Geometric Errors of Low Cost Desktop Publishing (DTP) Scanners

Abstract

Scanners have been used as input devices in photogrammetric and cartographic applications mainly for the digitization of aerial images and maps. Photogrammetric scanners are expensive while DeskTop Publishing (DTP) scanners have low prices, and may have good performance and sufficient resolution for the required applications. There are two types of DTP scanners: low-cost DTP scanners and high-cost DTP scanners. The main disadvantage of low-cost DTP scanners is the lack of geometric accuracy and stability. In addition, the scanner vendors rarely provide the users with software for accuracy testing and calibration.

This paper emphasizes developing software, called ScanCal, for testing the geometric accuracy and calibration of DTP scanners. An overview of the development and capabilities of the ScanCal software platform based on the Windows system is presented.

The developed software was used for testing the geometric accuracy of low-cost DTP scanners. The results show that the low-cost DTP scanners are unsuitable for photogrammetric applications but may be used for GIS-related applications. Furthermore, the results of the developed calibration method show that a geometric accuracy of 4-6 can be achieved. The achieved accuracy opens the door-way for using low-cost DTP scanners for photogrammetric applications.