title: Bilateral filter regularized accelerated Demons for improved discontinuity preserving registration.
abstract: The classical accelerated Demons algorithm uses Gaussian smoothing to penalize oscillatory motion in the displacement fields during registration. This well known method uses the L2 norm for regularization. Whereas the L2 norm is known for producing well behaving smooth deformation fields it cannot properly deal with discontinuities often seen in the deformation field as the regularizer cannot differentiate between discontinuities and smooth part of motion field. In this paper we propose replacement the Gaussian filter of the accelerated Demons with a bilateral filter. In contrast the bilateral filter not only uses information from displacement field but also from the image intensities. In this way we can smooth the motion field depending on image content as opposed to the classical Gaussian filtering. By proper adjustment of two tunable parameters one can obtain more realistic deformations in a case of discontinuity. The proposed approach was tested on 2D and 3D datasets and showed significant improvements in the Target Registration Error (TRE) for the well known POPI dataset. Despite the increased computational complexity, the improved registration result is justified in particular abdominal data sets where discontinuities often appear due to sliding organ motion.
authors.affiliation: Faculty of Electrical Engineering, University of Tuzla, Bosnia and Herzegovina. Electronic address: damir.demirovic@untz.ba.
authors.forename: D
authors.initials: D
authors.lastname: Demirović
authors.affiliation: Faculty of Electrical Engineering, University of Tuzla, Bosnia and Herzegovina. Electronic address: amira.serifovic@untz.ba.
authors.forename: A
authors.initials: A
authors.lastname: Šerifović-Trbalić
authors.affiliation: Faculty of Electrical Engineering, University of Tuzla, Bosnia and Herzegovina. Electronic address: naser.prljaca@untz.ba.
authors.forename: N
authors.initials: N
authors.lastname: Prljača
authors.affiliation: Medical Image Analysis Center (MIAC), University of Basel, Basel, Switzerland. Electronic address: philippe.cattin@unibas.ch.
authors.forename: Ph C
authors.initials: PC
authors.lastname: Cattin
mesh_terms: D000465:Algorithms; D016477:Artifacts; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
keywords: Bilateral filter; Demons method; Discontinuities; Image-guided therapy; Medical image registration