THORLABS WFS150, Руководство по эксплуатации

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67 Operating Instruction
© <2007> ... Thorlabs GmbH
take multiple images from the camera, average the pixel intensity pixel by pixel
and output an averaged image to the following evaluating routines. Due to
reduced intensity noise the accuracy of detected spot centroids is increased.
The available average settings are
whereas 3, 10, 30, 100 indicate normal averages where the average is taken in
the background and only after reaching the selected number of averaged images
the instrument will continue operation and start data evaluation and display. This
type of averaging also reduces the update rate of numerical and graphical data
on the main panel. This may be a beneficial effect for better reading the
numerics.
Settings 3 roll, 10 roll, 30 roll, 100 roll indicate pseudo rolling averages . Here,
the average of successive captured camera images is calculated every time a
new image is retrieved. A new image is added to a buffer that already contains
the averaged image and the summarized image is divided by the number of
averages. This way a pseudo rolling average across the last 3, 10, 30 or 100
images is retrieved. This type of averaging does not slow down the update rate on
the screen.
Exposure time and Gain
For normal operation it is highly recommended to select the 'Auto' setting. In this
case the Wavefront Sensor application program analyzes automatically the
maximum image intensity and adapts the control parameter 'Exposure time (ms)'
and 'Master Gain' correspondingly in order to reach a maximum image intensity
close to the maximum of 255 digits.
In rare cases of fluctuating light source intensity it may be helpful to deactivate
the 'Auto' feature and allow manual adjustments.
The
'Exposure' time can be set to values between 0,077 ms and 66.501 ms in
steps of 0.055 ms. 'Master Gain' indicates the analogue amplification factor of
the CCD sensor signal, it can be set to values between 1.00 and 5.00. It is