The sampling rate described as 2x per cycle is known as what concept in imaging?

• A. Aliasing
• B. Moiré pattern
• C. Nyquist
• D. Quantum noise

Answer: (C)

This is about the Nyquist criterion. To capture a pattern without distortion, you need to sample at least twice as often as the highest frequency present. Saying you have two samples per cycle means you’re at the minimum rate required to reconstruct that cycle, which is the Nyquist limit. If you sample at or above this rate, you avoid aliasing; sampling below it causes higher frequencies to masquerade as lower ones, creating artifacts. Aliasing is the unwanted outcome of under-sampling, while moiré patterns can appear when sampling interacts with fine spatial structure near this limit, and quantum noise relates to random fluctuations in detected signal. The concept described by “2x per cycle” is the Nyquist principle.