THEORY GUIDE
10DEC05
Fast Scan / Slow Scan Directions
TG4825-1
Page
36 of 120
Slow
Scan
The diagram indicates the direction of the 2 scanning actions for each size CASSETTE:
•
slow scan - the SCREEN moves vertically from up to down during scanning
•
fast scan - the laser beam moves horizontally across the SCREEN at the same time it
moves down
The slow scan direction for CASSETTES is important, because problems in the slow scan
process can cause artifacts in the image. For example, banding artifacts can appear across
the SCREEN in the horizontal direction, but the cause of the artifact might be a problem with
the vertical slow scan motion of the SCREEN.
43 cm
35 cm
35 cm
35 cm
Fast Scan
STORAGE PHOSPHOR CASSETTE
30 cm
30 cm
24 cm
15 cm
18 cm
24 cm
H194_5022BC