Image Filtering
lastmod 2023-10-26created 2023-10-245 edits
A filter is actually a concept borrowed from domain processing in the frequency domain. It is mainly used to remove the high-frequency components of an electronic signal (e.g. noise) or to remove the low-frequency components.
A filter in images is spatial filtering, that is, a filter that operates in the spatial domain rather than the frequency domain.
Low-Pass-Filter
A filter that passes only low frequencies.
With a low-pass filter (LPF), high frequencies do not pass, so edges can be softened, noise removed, and blurring applied.
High-Pass-Filter
A filter that passes only high frequencies.
With a high-pass filter (HPF), you can find edges in an image.
OpenCV APIs
- You can filter an image by applying a kernel (filter) to it with the function cv2.filter2D.