The hot-pixels are noticeably dimmed through the cooling created by the forced airflow.
The first inhouse test of the Watec camera established, that the small camera body got noticeably warm during operation. As the temperature of the ccd-chip is a significant source of noise, some experiments with cooling the camera body were made. To that behalf series of dark images were shot, with a small fan blowing ambient air (1°C) at the camera body.
The effects of the fan on the visibility of the "hot-pixels" was quite noticeable:
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The animated gif shows two images, which are each the median of a series of 35 dark images. Both series were taken with a unmodified camera, but in second series, a small fan created a continuous airflow across the camerabody. The hot-pixels are noticeably dimmed through the cooling created by the forced airflow. |
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The histograms of the dark images also show the effect of the cooling fan: The curve is shifted towards smaller brighnesses. |
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The diagram shows the standard deviation of all pixels, whose median brigtness values are identical. Here, no clear effect can be discerned. |
Go on to: Extended experiments with cooling