Xtium2-CXP PX8 User's Manual
CamExpert Quick Start
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Using the Flat Field Correction Tool
Flat Field Correction is the process of eliminating small gain differences between pixels in a sensor
array. That sensor when exposed to a uniformly lit field will have no gray level differences between
pixels when calibrated flat field correction is applied to the image. The CamExpert Flat Field tool
functions with hardware supporting flat field processing.
Xtium2-CXP PX8 Flat Field Support
The Xtium2-CXP PX8 supports hardware based real-time Flat Field Correction when used with a
monochrome video source. The Xtium2-CXP PX8 supports one method for pixel replacement:
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Neighborhood Replacement: a bad pixel is replaced with the average of its 2 neighbors on the
same video line.
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Note that the CXP Flat Field algorithm handles all cases of bad pixels, either on the video frame
edge or the neighboring pixels.
Loading the Required Camera File
Select the required camera configuration file for the connected camera. Verify the acquisition with
the live grab function. Make camera adjustments to get good images.
Set up Dark and Bright Acquisitions with the Histogram Tool
Before performing calibration, verify the acquisition with a live grab. Also at this time, make
preparations to grab a flat light gray level image, required for the calibration, such as a clean
evenly lighted white wall or non-glossy paper with the lens slightly out of focus. Ideally, a
controlled diffused light source aimed directly at the lens should be used. Note the lens iris position
for a bright but not saturated image. Additionally, check that the lens iris closes well or have a lens
cover to grab the dark calibration image.
Verify a Dark Acquisition
Close the camera lens iris and cover the lens with a lens cap. Using CamExpert, click on the grab
button and then the histogram button. The following figure shows a typical histogram for a very
dark image (8-bit acquisition).
