Quaternion switching filter for impulse noise reduction in color image

A novel approach to impulse noise reduction in color image is introduced in this paper. By applying the quaternion unit transform theory, the difference between two color pixels can be represented in the quaternion form. Based on the difference mentioned above, an efficient filter that can switch between the vector median filter (VMF) and the identity filter (no filtering operation) is proposed. Extensive simulation result indicates that the proposed filter achieves a trade-off between noise suppression and detail preservation in both correlated and uncorrelated impulse noise scenarios when compared with other widely used filters. Furthermore, the computational complexity analysis shows that the proposed filter is quite efficient.

► We propose a color pixel difference using the quaternion unit transform.
► The difference quantifies the intensity and chromaticity differences simultaneously.
► A switching vector median filter based on this difference is proposed.
► The filter achieves a balance between noise suppression and detail preservation.
► The filter has a lower computational complexity.