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Note: A positive offset value is not useful for contrast enhancement. However, it can be used while
measuring the dark noise level of the camera to ensure zero clipping is not present.
Help with Lens Focusing & Camera Alignment
See the section Camera Control Category in Appendix A for GenICam features associated with this
section and how to use them
Before evaluating the cameras imaging performance, it is important to ensure that the image is
properly focused and that the camera's 16k pixel axis is perpendicular to the motion of the object.
Establish Optimum focus
The target being used for focus adjustment should have sharp black-to-white transitions and as
much fine detail as possible. Ideally, black and white features of approximately 10 pixels or less
wide will be in the image. A back illuminated USAF 1951 target may be suitable.
Ensure that the lens aperture is fully open.
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Select the cameras 12 row mode.
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Select the low gain range and 1x gain.
Select a slow internal line rate of 5 kHz.
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Set exposure time to 100 µsec.
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Use the factory calibration settings.
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Adjust the target so that the fine details appear in the camera's field of view. Adjust the
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camera's gain so that the white parts of the image are at high values, but not saturated. If
the response is too high at 1x gain, then reduce the exposure time to 25 µsec or lower. Use
CamExpert to capture, display, and analyze the image. If insufficient response is achieved at
high gain, use the next highest gain range
Select the CamExpert histogram analysis tool.
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Using the mouse, drag a box over the image area with lots of fine detail you want to use for
focusing. The target should be stationary.
Adjust the lens' focus helical or the camera's working distance to the object until the
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histogram shows a maximum of dark and light peaks with the largest separation and the
lowest level of grey peaks.
Optimum focus should now be achieved.
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The Piranha XL Camera
Figure 9 USAF 1951 'Positive'
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