Kodak DirectView CR 800 System Theory Manual page 64

Illustration
12–64
[1] The two 16 bit values are sent to a FIFO buffer on the DIGITIZER BD where
it is buffered until a complete line of data, depending on the screen size) is
accumulated.
[2] In very rapid succession, while the GALVO is doing the retrace (quick
movement back to the 0 position at roughly10X the speed of the trace):
(a) The 32 bit line times the number of pixels in the line (for example 32 X
2048) is moved via DMA to the MCPU.
(b) The MCPU gets an interrupt that tells it that the line is done (its on the
MCPU) and it can start processing the line.
(c) The MCPU sets up the DIGITIZER BD to receive the next line.
Note
All the above actions are synchronized between the DIGITIZER BD and the
GALVO. The GALVO says a line is completed and the DIGITIZER says to start
again.
[3] The GALVO begins the trace of the next line on the plate.
[4] While the next line is being formed the MCPU processes the latest line it
received.
(a) The MCPU adjusts the pixel value based on the reference data, for
example if the laser was reading low at that moment, it is adjusted
upward.
(b) The Collector Profile is applied to each pixel to account for any
variation in the efficiency of the COLLECTOR.
[5] The MCPU converts the pixels from 16 bit linear values to12 bit log values.
Each pixel has a value between 0 and 4095. The image, minus the
reference data, is now a formatted "raw image" that is complete and resides
in a buffer on the MCPU. The process on the MCPU of assembling the data
and making the corrections to develop the raw image takes approximately
4 seconds.
Note
Recall that at the time the Barcode was read and the CASSETTE moved to the
Load position, the INTERNAL PC set up a 10 mg "RAW_IMAGE" file to receive
the raw image from the MCPU.
[6] A process that communicates with the PC sends the entire image to the PC
in one transmission.
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