Three-dimensional OCT Compressed Sensing using the shearlet transform under continuous trajectories sampling

Abstract

Background: Optical Coherence Tomography (OCT) is an emerging medical imaging technology. It is well suited to various medical applications requiring tissue imaging with micrometer resolution and millimeter penetration depth such as in ophthalmology and dermatology. Despite its numerous advantages, OCT has a long acquisition time for high-resolution images or volumes. This paper deals with the development of a Compressed, Sensing (CS) paradigm for faster 3-dimensional OCT image acquisition. Methods: The proposed framework includes three main steps: 1) defining a random-like and parameterizable and continuous scanning trajectories that must be compatible with a smooth mechanical scan, 2) rasterizing the scanning trajectory to make it achievable by a physical system (i.e. galvanometer mirrors), and 3) incorporating a high sparsifying data technique so-called 3D shearlet transform into the compressed sensing scheme. Actually, shearlet transform is mathematically optimal for multidimensional data decomposition and has been proven more efficient than classical ones such as those obtained by wavelet or curvelet transforms. Actually, shearlet system provides a very efficient tool for encoding anisotropic features (such as edges in images) in multivariate problem classes. Results: Numerical simulations and ex vivo experiments were carried out. The obtained results showed the ability of the proposed method to recover OCT images and volumes with high fidelity for different subsampling rates and scanning schemes, demonstrating the relevance of the proposed approach.

Keywords

• Optical Coherence Tomography
• Medical imaging
• Compressed Sensing
• Sparsity
• Shearlet transform
• Continuous scanning trajectories