Inventors:
George P. Lemeshewsky - Alexandria VA
Thomas O. Dando - Alexandria VA
Arthur R. Shope - Reston VA
Kenneth D. Kuck - Arlington VA
Assignee:
The United States of America as represented by the Secretary of the
Interior - Washington DC
International Classification:
G03B 2732
Abstract:
In an orthophotograph recorder, a three dimensional optical model of a terrain produced by a stereo pair of aerial transparencies is projected onto an imaging plate. The optical model is scanned by an optically produced reference point while the height of the viewing plate is manually adjusted by the operator to maintain the reference on the apparent ground level of the terrain. The scanning motion of the reference point, as well as the height of the imaging plate, is digitally encoded and formatted into data blocks. Each block of digital data represents an individual scan line on the optical model, and is characterized by a starting coordinate and incremental coordinate data. This data format minimizes storage requirements and permits editing of individual scan lines. The encoded data are scaled and stored on magnetic tape to be used to control exposure of a photosensitive sheet in an orthophotograph printer. The printer comprises a light projector located above a platen carrying the photosensitive sheet.