Abstract
Purpose: :
To reduce the speckle noise for improved structure segmentation on high-definition spectral domain optical coherence tomography (OCT).
Methods: :
Current despeckling methods applied to process noisy optical coherence tomography data take into consideration each B-scan individually, therefore looking to the 3D data set as a set of individual 2D images. In this way, the consistency of noise along the entire 3D data volume is not taken into account.In the work herewith presented, we have extended the application of complex diffusion filters from 2- to 3-dimensions therefore considering the entire volume as a single entity and not as a set of individual 2D entities.Eyes of 30 healthy volunteers and eyes of patients with age-related maculardegeneration (20), diabetic retinopathy (23), cystoid macular edema (2) and choroidal neo-vascularization (13) underwent high-definition spectral domain Cirrus OCT (Carl Zeiss Meditec, Dublin, CA, USA) using both the 200x200x1024 and the 512x128x1024 Macular Cube protocols.
Results: :
A total of 88 volumetric scans gathered with the Cirrus OCT were filtered using the new 3D nonlinear complex diffusion filter (3D-NCDF) as well as with implementation of available 2D filters, showing that the new 3D-NCDF filter allows for a better despeckling while preserving edges between retinal layers for eyes of healthy volunteers and patients with different pathologies.
Conclusions: :
The findings suggest that the speckle noise present in the Cirrus OCT can be successfully reduced while preserving important features using the newly developed 3D-NCDF filter.
Keywords: imaging/image analysis: clinical • image processing • retina