MOSAICKING IN . DIGITAL ENVIRONMENT

Abstract

The two data sources namely primary data from aerial photography, remotely sensed imagery and secondary data from maps are the input in computer-based GIS, which is presently occupying the centre-stage in various planning activities. These data sources represent parts of large continuum and are to, be registered for compatibility with other data sources. Digital mosaics are a valuable tool for planners, engineers and utility companies. Apart from these, digital mosaics have found its place in ECG diagnostics system and Earthquake monitoring system. Mosaic is an assembly of individual units like photographs, maps or imageries fitted together systematically to form a composite view of the entire area covered by them. In this dissertation, an attempt has been made to develop 'a •mosaicking process in digital environment which simulates conventional mosaicking. The instrument used is PC 486 with VGA monitor. The package developed facilitates the display of the image In 16 gray shades with user defined reduction factors. A cursor has been generated on the image and moved with predefined keys to select the control points. Controlled or uncontrolled mosaicking can be carried out using this package depending upon the control available on the photographs. An affine transformation is used for t scaling the images to make them compatible with. each other. Analytical rectification is applied to all the pixels in the images using the projective equations and the rectified image is displayed on the monitor. The potential, characteristics and operational aspects of the system are explained. Facility for real-time storage of the mosaic is provided in thesoftware so as to facilitate the user to invoke the mosaic photograph in future for subsequent processing. 5 (1V)