A fast directional sigma filter for noise reduction in digital TV signals

Mohammed Ghazal, Aishy Amer, Ali Ghrayeb

Research output: Contribution to journalArticle

8 Citations (Scopus)


This paper proposes a structure-oriented multidirectional Sigma filter for additive white Gaussian noise in digital TV signals. Filtering is restricted to homogeneous directions to reduce blurring by analyzing local structure using directional second derivatives. The proposed filter improves the Sigma estimate of denoised pixels by imposing a homogeneity constraint on the noise-adaptive selection of estimation pixels by the Sigma filter. It achieves noisereduction gains of up to 4.8 dB Peak-Signal-to-Noise Ratio (PSNR) in real-time. The block size, shape and coefficients of the filter are adapted to both structure and noise level. The goal is to optimize the filter with regard to oise-reduction gain and structure preservation. A possible hardwareoriented design of the proposed filter is also presented. To show the effectiveness of the proposed method, comparisons between the proposed Sigma filter and referenced Sigma filters in terms of the PSNR gain and the modulation transfer function (MTF) are shown. Results show that the proposed method achieves a higher PSNR gain and contrast transfer ratio than eferenced Sigma filters.

Original languageEnglish
Pages (from-to)1500-1507
Number of pages8
JournalIEEE Transactions on Consumer Electronics
Issue number4
Publication statusPublished - Nov 2007
Externally publishedYes



  • Digital TV noise
  • Real-time noise filters
  • Sigma filter
  • Spatial multi-directional filters
  • Structure preservation

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Computer Networks and Communications

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