This document describes an innovation in the field of electronic imaging: a high color linear CCD array is used for the recording of buildings. Data are used to create realistic digital models. We analyzed the usabiblity of linear CCD array for the mobile and autonomous documentation of architectural sites. Sensor motion of two different kinds is provided: we use car based translation to record facades of buildings, and a high precision rotation around different axes for the recording of inner courts, squares and indoor environments. like halls, churches or rooms. The recording images provide hight quality photo-texture and accurate geometric information to support the efficient generation of realistic digital models of buildings.
The creation of realistic computer models of buildings, architectural sites and entire cities is becoming an important task in several disciplines such as architecture, surveying, engineering, science and fine arts. The modeling and rendering of historical sites requires both geometrical detail and a high degree of realism in order to fulfill the demands of historical research and documentation as such. Photo-textured 3D CAD models of buildings, historical sites and cities are currently created manually and typically at great expense. Input data may consist of aerial images, data from geographical information systems, digitized maps or CAD informationm, and photos taken from indoors of from street level. The data acquision of the latter in one of the most expensive and time consumming phases in the modeling process. Up to now there has been no effective recording procedure or apparatus for this purpose in sight. Therefore we state as our goal the efficient and coherent acquisition of photo-texture and geometrical information of buildings to support modeling and documentation.
The innovation of this work is the mobile use of a line sensor for the latter recordings. We chose this line based approach for various reasons: line sensors are inexpensive, easily available, provide high geometrical resolution, acccuracy and an acceptable dynamic range and sufficient color fidelity. For the stated problems the mapping process is contiuous and more comprehensive compared to standard area sensor based technologies. Both geometric and photo-texture can efficient be recorded in a coherent way.
This thesis describes the navigation of a meanigful employment of a mobile recording platform based on a linear CCD. Compared to the well-known employment of such sensors in satellite or desktop scanners, fax and drum scanners in well defined environments, we recognize requirements and constraints given by challenging conditions like motion and changing light conditions. Major parts of this work deal with novel geometric and radiometric sensor calibration, and mobile and autonomous CCD line sensor employment under various environments. We conclude that the employment of a high resolution linear CCD array for building recording has the potential to become the recording technology for the future in this field. Altbough a highly automated modeling process cannot be expected to become reality in the short term, some phases will be greatly accelerated and improved: these are the recording as such and the reduced effort establishing coherences of geomeetry and photo-texture, as the latter input data are aquired in one step. A more effective and continuous recording process, the elegance of the mapping, and high quality data are the most evident advantages of the proposed procedure.