THORLABS BC207UV, Руководство по эксплуатации

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BC207 Series Chapter 5: The Graphics User Interface (GUI)
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MTN026962-D02
5.5.3.2 Exposure Control
Exposure time is the period of time when the CMOS global shutter is open and the image
sensor is exposed. For CW sources there is a linear dependency between exposure time and
mean image brightness. Increase the exposure time to increase brightness and vice versa.
1. Auto Exposure Control
The exposure control includes adjustments for exposure time and electrical gain factor. Both
settings determine the sensitivity of the camera and need to be adapted to the actual beam
power in order to ensure a nearly full scale amplitude measured by the camera's AD converter.
By default, both settings are controlled automatically in order to achieve an Image Saturation
between 80 and 95% of the available AD range.
It is highly recommended to use this automatic exposure control. When activated, the Beam
Profiler software will automatically adapt both the exposure time and gain. Both controls be-
come gray and display the actually used values. The goal is to keep the brightest pixel of the
selected ROI at a high saturation level but prevent saturation (100%) due to the limited range of
the AD converter that is digitizing the image.
However, in case of unstable or pulsed laser power it might be advantageous or even re-
quired to disable the automatic exposure control and set the optimal values manually. For this,
remove the 'Auto Exposure Control' check mark and follow the instructions below.
2. Manual Exposure Control
Exposure time can range from 0.03 ms to 1000 ms with a step width of 0.01 ms.
Use the arrows in order to increase and decrease the exposure time stepwise. The step size
is automatically adapted to the actual value so that a change of about 20% is achieved. To
enter a certain value just overwrite the present one.
5.5.3.3 Gain Control
The Gain can be set manually only with Auto Exposure disabled.
The Gain denotes the linear amplification factor of the electrical amplifier between the CMOS
sensor and the AD converter. Higher gain increases image brightness, but also image noise.
Therefore, it is recommended to use primarily the exposure time control for brightness adjust-
ments.
Gain settings higher than 0.00 should be used only if
· the exposure time is already set to its maximum value or
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