Spatially adaptive soft truncation based on the hierarchical correlation map and with the establishment of the threshold value based on local statistics
C. DUMITRESCU1,*
Affiliation
- Department Telematics and Electronics for Transports, National University of Science and Technology POLITEHNICA Bucharest, 313 Splaiul Independentei 060042, Bucharest, Romania, Energy & Eco Concept SR
Abstract
Most images have non-stationary properties, so they contain smooth regions and regions with abrupt transitions. These
regions with different characteristics can be well highlighted in the wavelet domain. The wavelet decomposition of an image
contains high and low energy areas (or coefficients with high and low absolute values). Maintaining the idea of point-wise
thresholding and exploiting the interband dependence by determining a map of accounts using the concept of hierarchical
correlation, in this article we propose and develop a new spatial adaptive filter that allows point-wise thresholding and
exploits the interband dependence by determining a map of accounts using the concept of hierarchical correlation, being
more efficient in terms of computational effort than the adaptive spatial filtering of wavelet coefficients with contextual
modeling. The proposed algorithm was tested on different images, and from the analysis of the obtained data it appears
that the effect of the threshold value used to obtain the contour map from the hierarchical correlation map does not depend
on the processed image (as in the case of optimal threshold values in the case of soft truncation), but only on the dispersion
of the disturbing noise.
Keywords
Wavelet, Adaptive filter, Noise reduction, Image processing.
Citation
C. DUMITRESCU, Spatially adaptive soft truncation based on the hierarchical correlation map and with the establishment of the threshold value based on local statistics, Optoelectronics and Advanced Materials - Rapid Communications, 19, 7-8, July-August 2025, pp.384-391 (2025).
Submitted at: April 4, 2025
Accepted at: Aug. 4, 2025