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ELiiXA® UC8/UC4
26
Eliixa_Color–revF 04/11
e2v semiconductors SAS 2011
The spatial correction has changed since the firmware version 3.0.0
On all previous versions, only the delays from 1 to 7 were available with the associated loop value.
For more information, please contact the Hotline :
hotline-cam@e2v.com
What is the Spatial correction ?
Vocabulary
:
w
= Pixel Size : 10µm in the Eliixa
W
= Size of the real object of the web seen by one pixel
M
= Magnification : M = w/W
p
= Color pitch or distance between to lines centers = 20µm in the
Eliixa
S
= Speed of the web.
For magnification of M, the line rate has to be adjusted at S/W
(see Chapter 5). Then, due to the fact that the color pitch is 2x the
pixel size, an area size of W which has been grabbed by the red line
at T will be grabbed by the Blue at T+2, by the Green at T+4 …
The Camera memorizes each line for each color from T to T+6.
The spatial correction of “2” allows to associate :
Red (T) + Blue(T+2) + Green (T+4) + Nir/BW(T+6) to be outputted in
the same time on the Camera Link connector.
Then the Spatial correction of “2” is for a pixel ratio (width/height) of 1/1 (“square pixels”).
We define the “width” in the sensor direction and the “height” in the web direction : A web speed which is 2x
times faster than the appropriate line rate to get square pixels will compress by 2 the pixels in the web
direction : In this case the ratio will be defined as 1/2.
But if the ratio is different, in order to avoid color artifacts, you’ve to adjust your spatial correction in the
following range :
Delay Ratio
Inhibited
-
0,5
1/4
1 1/2
1,5 2/3
2
1/1
3 3/2
4
2/1
5 5/2
6
3/1
T+6 T+5 T+4 T+3 T+2 T+1 T
Web Direction
Sensor
Lens
Example :
Sensor size = 40,96mm
(pixel size = 10µm)
Web Speed = 2200mm/s
Web Width = 500mm
Focal length = 65mm
Magnification = 0,08192 :
(sensor size/ Web width)
=> 10µ on the sensor
Ù
0,12207mm on the Web
At 18000l/s, the actual web speed (2200mm/s) is covered : The
spatial correction has to bet set to 2, the image ratio will be 1/1
Working distance => 793,5mm :
(Focal length / Magnification)
If the Web speed is set at 4400mm/s, the image ratio will be 1/2 and
then the Spatial correction has to be set to 1 (line rates remains
18000l/s for the Camera : It’s the max it can achieve.