calculation of sampling rate of an image

Hello everyone,i have a doubt…. I know that for a given signal, the sampling frequency Fs must be twice or more than maximum frequency of the signal Fm. It is easy to understand the concept for a 1D signal. But I don’t know how to calculate sampling frequency or Nyquist rate for a multidimensional signal like 2D image.So can anybody help regarding it???

[Rohan Sanghavi]

I have the same doubt.

Kindly please help.

Answer 1

[Omega]

Hi Ramdas,

When it comes to images, sampling works a bit differently than with 1D signals, but the core idea is the same.

• Spatial Sampling: Images are sampled in both horizontal and vertical directions, based on pixels per inch.
• Nyquist Rate: To avoid aliasing, sample at least twice the highest detail level in the image. This means capturing changes in pixel intensity properly.
• Practical Tip: To resolve the smallest features, your sampling frequency should be at least twice the size of those features.
• Resolution: Image resolution (like 300 DPI) is a measure of sampling rate. Higher DPI means capturing finer details.

In short, you don't usually calculate the sampling rate for images like 1D signals. Instead, you ensure the resolution is high enough to capture the details you need, often set by your camera or scanner.

I hope it helps!