THRESHOLD DETECTION OF GEODETIC SATELLITE IMAGES
Abstract
A literature survey and study has been made on the photographic detection of stellar images. Photographic detection theory in the literature was extended as required by the special conditions of geodetic satellite photography. These conditions include the optical and temporal characteristics of the laser illumination, the optical roughness of the satellite reflector, and the quality of detection desired. Experimental work was conducted to determine the energy requirements and the intrinsic location error for threshold images on Type 103-F emulsion. The energy required was found to be 150,000 to 450,000 photons at 6940A; the lower figure applied to objective detection with a microdensitometer having an aperture area equal to the nominal area of the image and requires optimum pre-exposure of the emulsion. The minimum rms location error varies from about 0.5 micron for well-exposed images (exposed over an area of 50-microns diameter) to 2 microns for threshold images. Failure of the reciprocity law, the effect of intermittent exposure, and scintillation due to the optically rough reflector are not significant. The basic results obtained for emulsion Type 103-F apply essentially to spectroscopic emulsions Types 1-N and 103a-U also.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 21, 1966
- Accession Number
- AD0648165
Entities
People
- Sumner Ackerman