For a pixel pitch of 0.050 mm, what is the Nyquist frequency?

For a pixel pitch of 0.050 mm, what is the Nyquist frequency?

• A. Five line pairs per millimeter
• B. Ten line pairs per millimeter
• C. Twenty line pairs per millimeter
• D. One line pair per millimeter

Answer: (B)

To determine the Nyquist frequency, you need to understand that it is defined as twice the maximum frequency that can be accurately sampled based on the linear resolution of a given pixel pitch. The Nyquist frequency is crucial in imaging to avoid aliasing.

In the context of a pixel pitch of 0.050 mm, the calculation involves first converting the pixel pitch to lines per millimeter. The formula to find the maximum frequency is:

Maximum Frequency = 1 / (2 × Pixel Pitch)

In this case, the pixel pitch is 0.050 mm, which can also be expressed as 0.000050 m. Therefore, calculating the maximum frequency:

1. Convert pixels to millimeters: 1 mm = 1000 μm, so

Pixel Pitch = 0.050 mm = 50 μm.

2. Calculate the Nyquist frequency:

Nyquist frequency = 1 / (2 × 0.050 mm) = 1 / 0.100 mm = 10 line pairs per mm.

Hence, the Nyquist frequency achieves a value of 10 line pairs per millimeter, which corresponds with the choice identified. This value indicates the highest spatial frequency that can be accurately represented given the pixel size