Реклама Google — средство выживания форумов :)
Для управления диафрагмой объектива может использоваться видеосигнал, подаваемый на пиковый детектор, постоянное напряжение с которого после усиления поступает на балансную дифференциальную схему (рис. 10.4). При изменении освещенности фотопреобразователя сигнал также изменяется, и навыходе балансной схемы образуется управляющее напряжение соответствующего знака.
........................
Вместе тем для универсального применения передающих камер может понадобиться расширение динамического диапазона до 104-105. С этой целью в камерах на видиконах применяют устройства авторегулирования напряжения на сигнальной пластине,
> http://window.edu.ru/resource/378/24378/files/itmo44.pdf
Вместе тем для универсального применения передающих камер может понадобиться расширение динамического диапазона до 104-105. С этой целью в камерах на видиконах применяют устройства авторегулирования напряжения на сигнальной пластине,
> http://window.edu.ru/resource/378/24378/files/itmo44.pdf
A high-resolution, 2-in return beam vidicon (RBV) television camera and a laser beam image reproducer (LBIR) have been selected by RCA as major components in an Earth Resources Satellite System. As part of a data handling study for the U.S. Department of the Interior, the RBV camera and LBIR were used to reproduce color picture transparencies to determine how well the camera/laser system could reproduce picture content, both photometrically and geometrically, and hence provide an indication as to what could be expected from its application in space observation systems. Fifteen color IR and Ektachrome transparencies, representing a wide variety of Gemini, Apollo and aerial photos, were selected for reproduction. Each transparency was mounted on a light source, and pictures were taken by the TV camera using in turn red, blue and green filters. Each video picture was transmitted to the laser reproducer and recorded on Hyscan film. This provided sets of color separation negatives which could be processed and registered using dye transfer techniques to form multicolor composites. An evaluation of these color prints indicates that the vidicon/Iaser system has the capability of reproducing to a high degree the photometric and geometric fidelity of the original scene; the high-resolution capability of the system enables the reproduction of much detail. Besides describing the features and operation of the RBV/-LBIR that make an effective observation system, the picture processing techniques are discussed and typical picture outputs are presented.
Published in: Journal of the SMPTE ( Volume: 79 , Issue: 3 , March 1970 )
> Color Picture Reproduction using a High-Resolution Television System - SMPTE Journals & Magazine
The Return Beam Vidicon (RBV) operated on Landsat satellites 1 and 2, and acquired approximately 1,600 sub-scenes at 80 meter resolution. The initial RBV sensor configuration used three independent cameras, each sensing a different spectral wavelength such as (0.48 to 0.83, 0.48 to 0.57, 0.58 to 0.68, and 0.70 to 0.83 micrometer). Landsat 1 and 2 RBV data were recorded to 70 millimeter (mm) black and white film rolls at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center and delivered to the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center for archiving and user distribution.
The RBV sensor utilized vidicon tube instruments containing an electron gun that read images from a photoconductive faceplate similar to television cameras The data stream received from the satellite was analog-to-digital preprocessed to correct for radiometric and geometric errors. The RBV system was redesigned for Landsat 3 to use a two-camera configuration mounted side by side that acquired four sub-scenes within the field of view of a Multispectral Scanner (MSS) scene. The Landsat 3 RBV spatial resolution is 40 meters with a spectral wavelength of 0.505 to 0.75 micrometer. Landsat 3 data were also recorded to 70 mm film until the EROS Digital Imagery Processing System (EDIPS) became operational in 1979. EROS Laser Beam Recorders (LBRs) recorded MSS and RBV data at 28 microns to 9-inch film rolls and the imagery was chipped up for archival storage and remains a viable archive backup to the digital MSS archive. However, all of the RBV digital archive data were purged for lack of computer compatible reasons. The last known collection of RBV tapes were disposed of in 2003.
Today, the RBV 70 mm and 9-inch film sources are maintained in the USGS EROS archive and are accessible through EarthExplorer as an on-demand film scanning product. RBV images that are scanned and the black and white images faithfully represent the Landsat RBV film archive as it exists today.
> USGS EROS Archive - Landsat Legacy - Return Beam Vidicon (RBV) Film Only