FOV
S
V
0
Pixel #1
Pixel #1
W
P
/ ß
CCD Sensor
Scan Object
Line Scan Camera SK2048GJR-4L Manual (09.2016) • shar
ed_CameraContr
ol(3)_Sync_ML.indd (09.2016)
18
SK2048GJR-4L
Instruction Manual
(09.2016)
© 2016
Schäfter + Kirchhoff GmbH
•
Hamburg
Camera Control and Performing a Scan
The optimum object scan velocity is calculated from:
W
P
· f
L
V
O
=
ß
If the velocity of the object carrier is not adjustable
then the line frequency of the camera must be adjusted
to provide an image with the correct aspect ratio,
where:
V
O
· ß
f
L
=
W
P
V
O
=
object scan velocity
W
P
=
pixel width
f
L
=
line frequency
S
=
sensor length
FOV
=
field of view
ß
= magnification
=
S / FOV
• A two-dimensional image is generated by moving either the object or the camera. The direction of the translation
movement must be orthogonal to the sensor axis of the CCD line scan camera.
• To obtain a proportional image with the correct aspect ratio, a
line-synchronous transport
with the laterally
correct pixel assignment is required. The line frequency and the constant object velocity have to be
coordinated.
• In cases of a variable object velocity or particularly high accuracy requirements then an
external synchroni-
zation
is necessary. The various
synchronization modes
are described below.
Example 1:
Calculating the object scan velocity for a given field of view and line frequency:
Pixel width
= 14 µm
Line frequency
= 4.73 kHz
S
=
28.7 mm
FOV
=
50 mm
14 µm · 4.73 kHz
V
O
=
(28.7 mm / 50 mm)
=
115 mm/s
Example 2:
Calculating the line frequency for a given field of view and object scan velocity:
Pixel width
= 14 µm
Object scan velocity
= 100 mm/s
S
=
28.7 mm
FOV
=
50 mm
100 mm/s · (28.7 mm / 50 mm)
f
L
=
14 µm
=
4.1 kHz
Synchronization of the Imaging Procedure and the Object Scan Velocity