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Appendix C: Quick Setup and Image Acquisition
Typically, the first thing you want to do is to evaluate the camera‘s image quality under
operating conditions similar to those that you are likely to use in your application. In order
to do this, take the following steps:
The illumination, lens magnification, and focus should be set up as per you
application.
Getting the magnification right is best accomplished by setting the object-to-sensor
distance. Use the formula
lens focal length x (2 + 1/magnifi magnification)
to calculate this distance. Magnification equals the sensor pixel size (7.05 µm) /
(your object pixel size in um).
The approximate location of the sensor position is at the first groove in the side of
the case, back from the front face.
4. Camera Timing & Control
It is easiest and quickest to evaluate the camera using the internal timing setups for line
rate and exposure time.
Since we recommend starting with Camera Link medium mode, set a suitable line
rate less than 20 KHz, using the ‗ssf‘ command.
If this line rate is too slow for your application, you will get a compressed image in
the scan direction. This should not be a problem for a basic evaluation.
You can set the exposure time using the ‗set‘ command. Ensure that the exposure
time period is not greater than the period of the line rate minus 1.5 µsec.
The camera will indicate an error if you select an exposure time that is too long. The
minimum exposure time is 8 µsec.
Set your camera direction using the ‗scd‘ command. Refer to the
diagram in this manual for a definition of ‗forward‘ and ‗reverse‘.
5. Acquiring an Image
You can now begin imaging. Unless you have an application employing lots of light, the
image is likely to be too dark.
Use the system gain to adjust the camera output to achieve the desired response.
The system gain range is from 1x to 10x.
Once you have a suitable response, you can now focus the lens.
If you are using white LEDs, your image will have reasonable color reproduction.
The image may be darker at the edges due to lens vignetting, but this will be
improved once the camera is calibrated.
Calibration is performed using a white reference where your object is normally
located.
o
Use a white material that has no texture, such as a non glossy plastic.
o
If you must use white paper, make sure it is moving during the calibration
process. If you do not do this, your image will have vertical stripes.
Calibration is easily performed using the TLC ‗cpa‘ command.
The cpa command has two parameters.
