title: Enhancement and bias removal of optical coherence tomography images: An iterative approach with adaptive bilateral filtering.
abstract: Optical coherence tomography (OCT) has continually evolved and expanded as one of the most valuable routine tests in ophthalmology. However, noise (speckle) in the acquired images causes quality degradation of OCT images and makes it difficult to analyze the acquired images. In this paper, an iterative approach based on bilateral filtering is proposed for speckle reduction in multiframe OCT data. Gamma noise model is assumed for the observed OCT image. First, the adaptive version of the conventional bilateral filter is applied to enhance the multiframe OCT data and then the bias due to noise is reduced from each of the filtered frames. These unbiased filtered frames are then refined using an iterative approach. Finally, these refined frames are averaged to produce the denoised OCT image. Experimental results on phantom images and real OCT retinal images demonstrate the effectiveness of the proposed filter.
authors.affiliation: Department of Electronics and Communication Engineering, National Institute of Technology, Tiruchirappalli, Tamil Nadu, India. Electronic address: spvnitt@gmail.com.
authors.forename: P V
authors.initials: PV
authors.lastname: Sudeep
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Singapore 639798, Singapore; Centre for Optical Fibre Technology (COFT), The Photonics Institute (TPI), Nanyang Technological University (NTU), Singapore 639798, Singapore.
authors.forename: S
authors.initials: S
authors.lastname: Issac Niwas
authors.affiliation: Department of Electronics and Communication Engineering, National Institute of Technology, Tiruchirappalli, Tamil Nadu, India.
authors.forename: P
authors.initials: P
authors.lastname: Palanisamy
authors.affiliation: Department of Computer Science and Engineering, National Institute of Technology, Karnataka, Surathkal, India.
authors.forename: Jeny
authors.initials: J
authors.lastname: Rajan
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Singapore 639798, Singapore; Centre for Optical Fibre Technology (COFT), The Photonics Institute (TPI), Nanyang Technological University (NTU), Singapore 639798, Singapore.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiaojun
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Singapore 639798, Singapore; Centre for Optical Fibre Technology (COFT), The Photonics Institute (TPI), Nanyang Technological University (NTU), Singapore 639798, Singapore.
authors.forename: Xianghong
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Singapore 639798, Singapore; Centre for Optical Fibre Technology (COFT), The Photonics Institute (TPI), Nanyang Technological University (NTU), Singapore 639798, Singapore.
authors.forename: Yuemei
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Centre for Optical Fibre Technology (COFT), The Photonics Institute (TPI), Nanyang Technological University (NTU), Singapore 639798, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University (NTU), Singapore 639798, Singapore.
authors.forename: Linbo
authors.initials: L
authors.lastname: Liu
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D059629:Signal-To-Noise Ratio; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*
keywords: Bilateral filtering; Denoising; Maximum likelihood estimation; Optical coherence tomography; Speckle noise