Medium-format Digital Cameras: a Study into Their Calibration, Stability Analysis, and Integration with High Resolution Satellite Imagery

Photogrammetry provides spatial and descriptive information from imagery that can be used in countless applications, including ortho-image production, map creation, construction planning, and military reconnaissance. The type of cameras traditionally used for these various applications were large format analog cameras. In recent years, however, the use of digital cameras for photogrammetric purposes has become more prevalent. The switch, by some users, from analog to digital cameras has been fueled by the decreasing cost and increasing resolution capabilities of digital cameras, in addition to their ease of use, availability, and rapid development. For some close range applications or for smaller flight blocks, the use of medium-format digital cameras (MFDC) has replaced the use of analog ones. In addition, digital photogrammetry has also spawned new markets in photogrammetric mapping with medium-format digital cameras. The growth of the field as well as the increase in the diversity of applications has numerous advantages; however, there are a few issues of concern which must be addressed, such as camera calibration and stability analysis. For these cameras, the burden of camera calibration, which has been shifted into the hands of the airborne data providers, has led to a need for the development of standards and procedures for simple and effective calibration. Therefore, this paper begins by addressing practical issues related to automated calibration of medium-format digital cameras, after which a stability analysis procedure will be introduced while considering the different geo-referencing alternatives. In addition, an investigation into the integration of MFDC with high resolution satellite imagery, for the purpose of enhancing the weak geometry of line scanners while benefiting from the large ground coverage offered by high resolution satellite imagery, will be presented.