Improving the quality of radiographic images acquired with conical radiation beams through divergence correction and filtering

37th Brazilian Meeting on Nuclear Physics

Silvani, M.I.^1 ; Almeida, G.L.^1 ; Latini, R.M.^2 ; Bellido, A.V.B.^2 ; Souza, E.S.^3 ; Lopes, R.T.^3

Instituto de Engenharia Nuclear - CNEN, Caixa Postal 68550, Rio de Janeiro - RJ

CEP 21945-970, Brazil^1

Instituto de Química - UFF, Outeiro de Sao Joao Baptista, s/no, Campos do Valonguinho, Niteroi - RJ

CEP 240020-150, Brazil^2

Laboratório de Instrumentação Nuclear - UFRJ, Caixa Postal 68509, Rio de Janeiro - RJ

CEP 21945970, Brazil^3

关键词: 2d fourier transforms;    Analytical geometry;    Conical radiation;    Gamma ray sources;    Histogram equalizations;    Radiographic images;    Statistical fluctuations;    Trial-and-error approach;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/630/1/012013/pdf
DOI  :  10.1088/1742-6596/630/1/012013

来源: IOP

【 摘 要 】

Earlier works have shown the feasibility to correct the deformation of the attenuation map in radiographs acquired with conical radiation beams provided that the inspected object could be expressed into analytical geometry terms. This correction reduces the contribution of the main object in the radiograph, allowing thus the visualization of its otherwise concealed heterogeneities. However, the non-punctual character of the source demanded a cumbersome trial-and-error approach in order to determine the proper correction parameters for the algorithm. Within this frame, this work addresses the improvement of radiographs of specially tailored test-objects acquired with a conical beam through correction of its divergence by using the information contained in the image itself. The corrected images have afterwards undergone a filtration in the frequency domain aiming at the reduction of statistical fluctuation and noise by using a 2D Fourier transform. All radiographs have been acquired using165Dy and198Au gamma-ray sources produced at the Argonauta research reactor in Institutode Engenharia Nuclear - CNEN, and an X-ray sensitive imaging plate as detector. The processed images exhibit features otherwise invisible in the original ones. Their processing by conventional histogram equalization carried out for comparison purposes did not succeed to detect those features.