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randa177
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I am learning about CCD s, and I always get the term BIAS, but I can't find any clear definition of what that is, can anybody help please?
Thanks,
Randa
Thanks,
Randa
Waveform said:I am assuming you mean CCD 'bias frames'
A CCD bias frame is taken with zero length exposure setting and the shutter closed. It essentially brings up camera noise. The bias frame will read noise of the CCD and computer system.
I think most modern CCD are well compensated in the noise area, both internal and external.
I have a lower end CCD on my scope and I don’t bother with bias frames. However, I will take dark frames.
As opposed to bias frames a dark frame is taken a with time exposure element and shutter open, however the scope is absent of light or covered to not allow any light.
If the CCD camera will extrapolate the noise of the bias frame the dark frame has only the thermal noise.
Here is a link the will explain. To cover it all here would be quite a long post.
Hope this helps.
http://www.aavso.org/observing/programs/ccd/manual/3.shtml"
BIAS refers to the systematic deviation or error in a measurement or calculation, usually towards a particular direction or value.
BIAS can be caused by a variety of factors, such as faulty equipment, human error, or inherent limitations in the measurement process.
BIAS can significantly impact the results of scientific research by skewing the data and leading to incorrect conclusions. It is important for scientists to identify and minimize BIAS in their experiments and analyses.
A CCD (charge-coupled device) is a type of image sensor commonly used in digital cameras and scientific instruments to capture and convert light into electronic signals.
Randa is a tool that allows scientists to simulate the behavior of CCDs in different conditions. By using Randa, scientists can better understand how CCDs work, how they respond to different light sources, and how to minimize BIAS in their measurements.