Allied Vision Goldeye G, Техническое руководство

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106 Goldeye G Technical Manual V 2.0.0
Temperature control
Principle of operation
During operation, power consumed and dissipated by the internal electronic
components causes the interior and case of the camera to heat up.
An increase in sensor temperature has a negative impact on the image quality of
the InGaAs sensor (FPA), for several reasons.
• The dark current of the FPA‘s photo diodes increases: as a rule of thumb, a
temperature increase of 8 K doubles the dark current. The dark current pro ‐
duces additional noise, especially at longer exposure times, which causes a
decrease in image contrast.
• The spectral sensitivity may change: a difference in temperature may cause the
sensitivity curve to drift or to become slightly narrower.
• Certain components of the InGaAs sensor are prone to temperature drift.
Therefore, to ensure a consistently optimum image quality, the influence of
temperature change needs to be minimized. Two measures are taken to achieve
this:
1. Temperature
control of the sensor
2. Neutralization of the temperature influence
These measures are described in detail below.
Warm ‐ up period
After switching on the camera, the sensor temperature stabilizes and optimal
image quality is reached within one minute.
The Stable temperature state is indicated by the green temperature status LED.
Temperature control of the sensor
The InGaAs sensor is affected by temperature in two ways:
1. Fluctuation of temperature:
If the temperature influence on the sensor remains constant, this ensures con ‐
stantly high image quality. To achieve this, the temperature of the sensor is sta ‐
bilized at one of several defined setpoints.
Caution:
Burns
to the skin possible if camera housing is hot.
The camera housing may heat up during operation. Touching the camera with bare
hands may lead to injuries.
Wear protective gloves when touching a heated ‐ up camera during operation.
Also, use proper heat dissipation methods to keep the camera as cool as possible.