INPE's line imaging camera: Preliminary results

INPE has been working in the development of a pushbroom type of sensor. The first prototype of INPE's pushbroom camera includes a commercial type optical system (Hasselblad lens) and a 1728-element CCD array (Fairchild CCD 122). In a preliminary evaluation, data acquired in the first flight was converted to digital form in order obtain both CCTs and film products for qualitative and quantitative analysis. A three bar ground target was used to study the geometric characteristics of the sensor system as compared to those of conventional aerial photographs, taken simultaneously during the same test flight. Analysis of the first results have shown that: (1) The sensor system met most of the specified characteristics for a prototype. (2) Aircraft (e.g., yaw) and image (e.g., smearing) motions contributed to the major geometric distortions. (3) Particularly, bright targets tended to show an enhanced effort of line to line misregistration (line to line shifts were mainly due to the lack of synchronization during the A/D conversion process). (4) Although a preset geometric resolution of 76cm (3000m - overflight) was not obtained, objects at small as 30cm wide were, radiometrically, resolved.