Phase Asymmetry Ultrasound Despeckling with Fractional Anisotropic Diffusion and Total Variation

Kunqiang Mei, Bin Hu, Baowei Fei, Binjie Qin

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


We propose an ultrasound speckle filtering method for not only preserving various edge features but also filtering tissue-dependent complex speckle noises in ultrasound images. The key idea is to detect these various edges using a phase congruence-based edge significance measure called phase asymmetry (PAS), which is invariant to the intensity amplitude of edges and takes 0 in non-edge smooth regions and 1 at the idea step edge, while also taking intermediate values at slowly varying ramp edges. By leveraging the PAS metric in designing weighting coefficients to maintain a balance between fractional-order anisotropic diffusion and total variation (TV) filters in TV cost function, we propose a new fractional TV framework to not only achieve the best despeckling performance with ramp edge preservation but also reduce the staircase effect produced by integral-order filters. Then, we exploit the PAS metric in designing a new fractional-order diffusion coefficient to properly preserve low-contrast edges in diffusion filtering. Finally, different from fixed fractional-order diffusion filters, an adaptive fractional order is introduced based on the PAS metric to enhance various weak edges in the spatially transitional areas between objects. The proposed fractional TV model is minimized using the gradient descent method to obtain the final denoised image. The experimental results and real application of ultrasound breast image segmentation show that the proposed method outperforms other state-of-the-art ultrasound despeckling filters for both speckle reduction and feature preservation in terms of visual evaluation and quantitative indices. The best scores on feature similarity indices have achieved 0.867, 0.844 and 0.834 under three different levels of noise, while the best breast ultrasound segmentation accuracy in terms of the mean and median dice similarity coefficient are 96.25% and 96.15%, respectively.

Original languageEnglish (US)
Article number8906234
Pages (from-to)2845-2859
Number of pages15
JournalIEEE Transactions on Image Processing
StatePublished - 2020


  • Ultrasound despeckling
  • edge detection
  • fractional-order TV filter
  • fractional-order diffusion filter
  • image denoising
  • phase asymmetry
  • phase congruency
  • speckle noise

ASJC Scopus subject areas

  • Software
  • Computer Graphics and Computer-Aided Design


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