title: Local and Non-local Regularization Techniques in Emission (PET/SPECT) Tomographic Image Reconstruction Methods.
abstract: Emission tomographic image reconstruction is an ill-posed problem due to limited and noisy data and various image-degrading effects affecting the data and leads to noisy reconstructions. Explicit regularization, through iterative reconstruction methods, is considered better to compensate for reconstruction-based noise. Local smoothing and edge-preserving regularization methods can reduce reconstruction-based noise. However, these methods produce overly smoothed images or blocky artefacts in the final image because they can only exploit local image properties. Recently, non-local regularization techniques have been introduced, to overcome these problems, by incorporating geometrical global continuity and connectivity present in the objective image. These techniques can overcome drawbacks of local regularization methods; however, they also have certain limitations, such as choice of the regularization function, neighbourhood size or calibration of several empirical parameters involved. This work compares different local and non-local regularization techniques used in emission tomographic imaging in general and emission computed tomography in specific for improved quality of the resultant images.
authors.affiliation: Institute of Nuclear Medicine and Oncology (INMOL), New Campus Road, Lahore, PC 10068, Pakistan. munirahm@gmail.com.|Department of Physics, The University of Lahore, Pakistan, 1-KM Raiwind Road, Lahore, 54000, Punjab, Pakistan. munirahm@gmail.com.
authors.forename: Munir
authors.initials: M
authors.lastname: Ahmad
authors.affiliation: Department of Physics, The University of Lahore, Pakistan, 1-KM Raiwind Road, Lahore, 54000, Punjab, Pakistan.
authors.forename: Tasawar
authors.initials: T
authors.lastname: Shahzad
authors.affiliation: Institute of Nuclear Medicine and Oncology (INMOL), New Campus Road, Lahore, PC 10068, Pakistan.
authors.forename: Khalid
authors.initials: K
authors.lastname: Masood
authors.affiliation: Applied Physics, Pakistan Council of Science and Industrial Research (PCSIR), Ferozpur Road, Lahore, Pakistan.
authors.forename: Khalid
authors.initials: K
authors.lastname: Rashid
authors.affiliation: Department of Physics, The University of Lahore, Pakistan, 1-KM Raiwind Road, Lahore, 54000, Punjab, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Tanveer
authors.affiliation: Department of Physics, The University of Lahore, Pakistan, 1-KM Raiwind Road, Lahore, 54000, Punjab, Pakistan.
authors.forename: Rabail
authors.initials: R
authors.lastname: Iqbal
authors.affiliation: Institute of Nuclear Medicine and Oncology (INMOL), New Campus Road, Lahore, PC 10068, Pakistan.
authors.forename: Nasir
authors.initials: N
authors.lastname: Hussain
authors.affiliation: Institute of Nuclear Medicine and Oncology (INMOL), New Campus Road, Lahore, PC 10068, Pakistan.
authors.forename: Abubakar
authors.initials: A
authors.lastname: Shahid
authors.affiliation: Department of Physics, The University of Lahore, Pakistan, 1-KM Raiwind Road, Lahore, 54000, Punjab, Pakistan.
authors.lastname: Fazal-E-Aleem
mesh_terms: D000465:Algorithms; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography; D015899:Tomography, Emission-Computed, Single-Photon
keywords: Ill-posedness; Maximum a posteriori (MAP) reconstruction; Non-local priors; Regularization; Tomographic image reconstruction