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3 Camera Control and Performing a Scan
RGB Sensors: 2D Imaging and Pixel Allocation
The three lines of the implemented triple line sensor are
sensitive for the primary colors red (R), green (G) and blue
(B). For the spectral sensitivity characteristics see 27.
The pixel width W
is 14 µm, the line spacing W
p
which is 8 times the pixel width.
During object travel, an object point reaches the red line
sensor first. If the object is transla ted by one pixel height
per clock pulse then after 8 lines the green pixels are
exposed. After another 8 lines then the blue pixels have
been covered and all color information has been acquired.
W
/ ß
L
Pixel #1
FOV
W
/ ß
P
V
:
object scan velocity
O
W
:
pixel width = pixel height H
P
(for sensors with square pixels)
W
:
line spacing
L
S:
sensor length
FOV:
field of view
ß:
magnification = S / FOV
© 2015
Schäfter + Kirchhoff GmbH • Hamburg
is 112 µm.
L
S
CCD Sensor
Pixel #1
V
0
Scan
Object
B
G
R
P
SK6288GKOC-L Instruction Manual (06.2015)
The Camera SK6288GKOC-L provides the red (R), green
(G) and blue (B) informations se quentially in one single
video output signal.
The co lor information originating from the different parts
of the object is stored in the buffer of the PC and subse-
quently reallocated correctly.
PC memory of camera data
column no.
1 2 3
line no.
1
R G B
...
9
R G B
...
17
R G B
...
line scan 17
object location no.
1
RGB
Generating the color information of object
locations for display
Triple line sensors require a precise synchronous trans-
lation of the object for the correct allocation of pixels.
Also the transport direction has to conform to the
sequence of the line acquisition: First blue (B) then
green (G) and red (R).
When these conditions are not met then images with
co lor convergence ab er rations are generated.
A
B
Monochrome font pattern
line synchronous object transport
A
asynchronous transport of the object
B
causes color convergence aberration
4 5 6
7 8 9
...
6288
R G B
R G B
...
R G B
R G B
R G B
...
R G B
R G B
R G B
...
R G B
2
3
...
2096
RGB
RGB
...
RGB
21
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