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Section 12: Image Acquisition and Processing
Image acquisition and processing involves 3 primary sequences: scanning, acquisition, and processing. Throughout these processes much of the activity is
synchronized by the Digitizer BD and the Galvo ??BD??.
Scanning Sequence
Pre-scanning Conditions
Prior to the optical start of scan, the Plate has reached the mechanical Start of Scan. The MCPU has issued a "go to plate" command and received a "go to plate"
response indicating that it is at a fixed position ready for the optical scan to begin.
The PMTs are on high and are zeroed. The Laser Shutter is open and the voltage checked.
1234563 – 12/12/94
[1] The MCPU sends the size speed information to the GALVO BD to set up the
GALVO for the PLATE to be scanned.
• Offset and amplitude
• PMT gains ?? what is being done here??
[2] When the MSC Bd is ready, it sends a message to the MCPU, and the
MCPU tells the Galvo to start moving. At the same time, it tells the PMT/
DAS BD that the scan is starting.
Note
This ?? constitutes the Optical Start of Scan. ? is this true, just what signals the
Optical start of scan?? What command??
[3] The The Galvo
See "Galvo Operation."
beam onto the PLATE.
?? are these on the plate, e. g. the alum edge??
or prior to the lead edge reaching the point of scan??
Note
The GALVO scans a few lines, before acquiring data ?? for what prupose?/. The
number of lines it scans prior to actual data acquisition is set up in calibration
based on the PLATE size.
[4] The PLATE moves with extremely controlled velocity and smoothness in
the slow scan direction. At the same time, the LASER scans across the
plate in a nearly horizontal direction. Both movements are preset based on
configuration data for the particular PLATE size. The MSC controls the
Slow Scan movement through the SLOW SCAN CONTROLLER BD and
the Digitizer BD controls the fast scan movement through the GALVO BD.
Image Acquisition and Processing
starts up and directs theLASER
12–59
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