Filtering out low-frequency bias

1. What is low frequency filtering?
2. What type of filter do we use to remove low frequencies?
3. What is low pass filtering in radiology?

What is low frequency filtering?

A low-pass filter (LPF) is a circuit that only passes signals below its cutoff frequency while attenuating all signals above it. It is the complement of a high-pass filter, which only passes signals above its cutoff frequency and attenuates all signals below it.

What type of filter do we use to remove low frequencies?

It is called a low-pass filter because it allows low-frequency signals to pass through, while attenuating (reducing the amplitude of) higher-frequency signals. If you've been around a DAW, you've doubtlessly seen a low-pass filter in the wild.

What is low pass filtering in radiology?

A low-pass filter, also called a "blurring" or "smoothing" filter, averages out rapid changes in intensity. The simplest low-pass filter just calculates the average of a pixel and all of its eight immediate neighbors.