Changing Analog Signals To Digital Signals - Kodak DirectView CR 825 Theory Manual

THEORY GUIDE
10DEC05

Changing Analog Signals to Digital Signals

TG4825-1
Page
21 of 120
Y
analog image
(continual values)
Analog signals are changed to digital signals by sampling the blue light from the STORAGE
PHOSPHOR SCREEN and moving it through an ANALOG-TO-DIGITAL CONVERTER to
make a digital value for the brightness of each sample.
Sampling is similar to making a photograph of the signal at a given time. The sample has
both a horizontal and a vertical value. The size of the sample is defined in the system
software for both the horizontal and vertical directions.
• The horizontal value indicates a point in time in the motion of the laser beam across the
SCREEN.
• The vertical value indicates a line on the screen at a right angle to the scanning direction.
image
sample
grid
X
pixel code value
(0 - 4095)
SAMPLING
image
matrix
digital image
(discrete values)
Radiography Theory
H194_5014HC