Regression-based algorithm for bulk motion subtraction in optical coherence tomography angiography

Acner Camino, Yali Jia, Gangjun Liu, Jie Wang, David Huang

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


We developed an algorithm to remove decorrelation noise due to bulk motion in optical coherence tomography angiography (OCTA) of the posterior eye. In this algorithm, OCTA B-frames were divided into segments within which the bulk motion velocity could be assumed to be constant. This velocity was recovered using linear regression of decorrelation versus the logarithm of reflectance in axial lines (A-lines) identified as bulk tissue by percentile analysis. The fitting parameters were used to calculate a reflectance-adjusted upper bound threshold for bulk motion decorrelation. Below this threshold, voxels are identified as non-flow tissue, their flow values are set to zeros. Above this threshold, the voxels are identified as flow voxels and bulk motion velocity is subtracted from each using a nonlinear decorrelation-velocity relationship previously established in laboratory flow phantoms. Compared to the simpler median-subtraction method, the regression-based bulk motion subtraction improved angiogram signal-to-noise ratio, contrast, vessel density repeatability, and bulk motion noise cleanup in the foveal avascular zone, while preserving the connectivity of the vascular networks in the angiogram.

Original languageEnglish (US)
Article number#290746
JournalBiomedical Optics Express
Issue number6
StatePublished - Jun 1 2017


  • Image enhancement
  • Motion detection
  • Ophthalmology
  • Optical coherence tomography

ASJC Scopus subject areas

  • Biotechnology
  • Atomic and Molecular Physics, and Optics


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