Nyquist frequency and detector sampling: what is it and why is it relevant?

Nyquist frequency and detector sampling: what is it and why is it relevant?

• A. It is half the sampling rate, and it determines the highest spatial frequency that can be accurately represented to avoid aliasing.
• B. It is the full sampling rate.
• C. It is unrelated to sampling.
• D. It is twice the sampling rate.

Answer: (A)

The Nyquist frequency is the highest spatial frequency you can faithfully represent when you sample an image. It equals half the sampling rate. In a detector, the sampling rate corresponds to how many samples (pixels) you take per unit length, so the Nyquist limit becomes 1 divided by twice the pixel pitch. This limit matters because patterns finer than Nyquist will be misrepresented due to aliasing, creating artifacts. To preserve details, you either increase the sampling rate (smaller pixels) or remove higher frequencies before sampling with an anti-aliasing filter. That’s why this answer is correct: it ties half the sampling rate to the maximum accurately representable spatial frequency and the need to avoid aliasing.

The Nyquist frequency is the highest spatial frequency you can faithfully represent when you sample an image. It equals half the sampling rate. In a detector, the sampling rate corresponds to how many samples (pixels) you take per unit length, so the Nyquist limit becomes 1 divided by twice the pixel pitch. This limit matters because patterns finer than Nyquist will be misrepresented due to aliasing, creating artifacts. To preserve details, you either increase the sampling rate (smaller pixels) or remove higher frequencies before sampling with an anti-aliasing filter. That’s why this answer is correct: it ties half the sampling rate to the maximum accurately representable spatial frequency and the need to avoid aliasing.