2.2 - PRE-PROCESSING
Introduction
The Digital Processing Section is equipped with high density digital
recorders identical to those at the DAF for play-back of data, three
mini-computer based processing systems called the Bulk Processing System
(BPS), the Precision Processing System (PPS) and the Development
Processing System (DPS), four large disk storage systems, image writers,
digital magnetic tape units and other standard peripherals.
Four levels of processing are provided, the first three being performed by
the BPS and the fourth by the PPS. These are:
(a) reduced resolution imagery for cataloguing;
(b) quick-look imagery;
(c) bulk processing;
(d) precision processing.
Resolution Reduction
On receipt of the high density digital tapes from the DAF, and prior to
storage in the archive area, the data are played back onto computer disk
file at reduced resolution. The data base containing listings of
previously acquired scenes is updated and the images of every scene are
examined on a colour TV style monitor for cloud cover and quality. This
information is entered manually into the data base. The data base is read
out to magnetic tape at monthly intervals (approx. two satellite coverage
cycles) for subsequent production of a microfiche Data Catalogue. At the
end of each satellite coverage cycle the disk file is written out onto
colour negatives in the standard "times 24" microfiche format in the form
of a complete set of micro-images of all scenes acquired.
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