Calculate the spatial frequency if the pixel size is 0.03 mm. spatial frequency = 1/(2 x pixel size)

Calculate the spatial frequency if the pixel size is 0.03 mm. spatial frequency = 1/(2 x pixel size)

• A. 33.33 lp/mm
• B. 16.67 lp/mm
• C. 8.34 lp/mm
• D. 0.06 lp/mm

Answer: (B)

Spatial frequency in imaging is limited by how finely you sample the image with pixels, governed by the Nyquist principle. You can represent up to half the sampling rate, which means the highest spatial frequency is 1 divided by twice the pixel size. With a pixel size of 0.03 mm, twice that size is 0.06 mm. So the maximum spatial frequency is 1 / 0.06 mm = 16.67 cycles per millimeter, i.e., 16.67 lp/mm. This is the value that matches the given calculation. If you used 1/(pixel size) you’d get 33.33 lp/mm, which overshoots what the sampling actually supports. The other options correspond to misapplying the formula or different denominators, not the Nyquist-limited result.

Spatial frequency in imaging is limited by how finely you sample the image with pixels, governed by the Nyquist principle. You can represent up to half the sampling rate, which means the highest spatial frequency is 1 divided by twice the pixel size.

With a pixel size of 0.03 mm, twice that size is 0.06 mm. So the maximum spatial frequency is 1 / 0.06 mm = 16.67 cycles per millimeter, i.e., 16.67 lp/mm. This is the value that matches the given calculation.

If you used 1/(pixel size) you’d get 33.33 lp/mm, which overshoots what the sampling actually supports. The other options correspond to misapplying the formula or different denominators, not the Nyquist-limited result.