Genie Color Series-GigE Vision Camera
Operational Reference
63
Average bright pixel value
(bright gray but not white)
Maximum should not be
peak white unless there is a
“hot” pixel (i.e. 255 for 8-bit,
1023 for 10-bit)
Minimum should not be black
unless there is a “dead” pixel
Important:
In this example, the
average
pixel value for the frame is bright gray. Also note that sensors may show
a much higher maximum or a much lower minimum pixel value due to one or more "hot or dead pixels". The
sensor specification accounts for a small number of hot, stuck, or dead pixels (pixels that do not react to light over
the full dynamic range specified for that sensor).
Once the bright gray acquisition setup is done, note the camera position and lens iris position so as to be able to
repeat it during the calibration procedure.
Flat Field Correction Calibration Procedure
The following procedure uses the CamExpert Flat Field tool (the Sapera Flat Field demo is similar). Calibration is
the process of taking two reference images, one of a dark field – one of a light gray field (not saturated), to generate
correction data for images captured by Genie. Each sensor pixel data is modified by the correction factor generated
by the calibration process, so that each pixel has an identical response to the same illumination.
With Genie color cameras, calibration requires that the Pixel Format is first changed to
Bayer Raw8
mode. This is
so because the calibration calculations are done on the host computer, then uploaded to the Genie. The user or
application then returns the Genie Pixel Format to
RGB 32-bit
,
UYVY
, or
YUY2
for image acquisition with flat
field correction (as shown in the following two screen shots).
