Fast and accurate projection algorithm for 3D cone-beam reconstruction with the Algebraic Reconstruction Technique (ART)

Ultrasonic through-transmission data processed using the back-projection algorithm offers depth and lateral information about a defect beyond the capabilities of current through-transmission techniques. This technique was trialled on a carbon steel block containing side-drilled holes. Imaging artefacts can arise from the use of the backprojection algorithm, due to applying a weighting of one to each pixel, irrespective of how much of the pixel is intersected by the beam. Noise can also occur within the image where there are few intersections of the pixels made. This is seen at the edges of the image. In this paper, a novel back-projection technique utilises the weighting of pixels, dependent on the normalised weight of the beam that intersects them, to reduce any artefacts that occurred previously due to the backprojection algorithm. This paper also explores the use of the algebraic reconstruction technique (ART) algorithm for noise removal, thus increasing the sharpness of the defect.

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An Accelerated Iterative Cone Beam Computed Tomography Image Reconstruction Approach

Al-Nahrain Journal for Engineering Sciences ◽

10.29194/njes.22040307 ◽

2019 ◽

Vol 22 (4) ◽

pp. 307-314

Author(s):

Shimaa Abdulsalam Khazal ◽

Mohammed Hussein Ali

Keyword(s):

Computed Tomography ◽

Cone Beam Computed Tomography ◽

Iterative Reconstruction ◽

Cone Beam ◽

Reconstruction Technique ◽

Algebraic Reconstruction Technique ◽

Reconstruction Algorithms ◽

Reconstruction Process ◽

Reconstruction Time ◽

Algebraic Reconstruction

Cone-beam computed tomography (CBCT) is an indispensable method that reconstructs three dimensional (3D) images. CBCT employs a mathematical technique of reconstruction, which reveals the anatomy of the patient’s body through the measurements of projections. The mathematical techniques employed in the reconstruction process are classified as; analytical, and iterative. The iterative reconstruction methods have been proven to be superior over the analytical methods, but due to their prolonged reconstruction time those methods are excluded from routine use in clinical applications. The aim of this research is to accelerate the iterative methods by performing the reconstruction process using a graphical processing unit (GPU). This method is tested on two iterative-reconstruction algorithms (IR), the algebraic reconstruction technique (ART), and the multiplicative algebraic reconstruction technique (MART). The results are compared against the traditional ART, and MART. A 3D test head phantom image is used in this research to demonstrate results of the proposed method on the reconstruction algorithms. The simulation results are executed using MATLAB (version R2018b) programming language and computer system with the following specifications: CPU core i7 (2.40 GHz) for the processing, with a NIVDIA GEFORCE GPU. Experimental results indicate, that this method reduces the reconstruction time for the iterative algorithms.

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