image processing - How does separating frequencies by Gaussian Filter work? -

i want understand meaning of separating frequencies using gaussian filter. give me meaningful example?

gaussian kernel low pass filter (lpf).
means every time applied on image removes high frequency data.

now think following process, apply lpf on image, resulted image called lpf_k. take image_k (original image @ k-th step) , hpf_k = image_k - lpf_k.
why hpf (high pass filter)? because took image contains frequencies , remove lpf part of leaves hpf.

it means seprated lpf data of image , hpf.

if insert downsampling , upsampling process in between can split frequencies want (filter banks).

this how equalizer work example.

you can read more in filter banks.

this lies behind wavelets, multi scale analysis , pyramid decomposition in image processing.