title: A sparse reconstruction algorithm for ultrasonic images in nondestructive testing.
abstract: Ultrasound imaging systems (UIS) are essential tools in nondestructive testing (NDT). In general, the quality of images depends on two factors: system hardware features and image reconstruction algorithms. This paper presents a new image reconstruction algorithm for ultrasonic NDT. The algorithm reconstructs images from A-scan signals acquired by an ultrasonic imaging system with a monostatic transducer in pulse-echo configuration. It is based on regularized least squares using a l1 regularization norm. The method is tested to reconstruct an image of a point-like reflector, using both simulated and real data. The resolution of reconstructed image is compared with four traditional ultrasonic imaging reconstruction algorithms: B-scan, SAFT, ω-k SAFT and regularized least squares (RLS). The method demonstrates significant resolution improvement when compared with B-scan-about 91% using real data. The proposed scheme also outperforms traditional algorithms in terms of signal-to-noise ratio (SNR).
authors.affiliation: Graduate School on Electrical Engineering and Applied Computer Science, Federal University of Technology-Paraná (UTFPR), Curitiba-PR 80230-901, Brazil. giovanni@utfpr.edu.br.
authors.forename: Giovanni Alfredo
authors.initials: GA
authors.lastname: Guarneri
authors.affiliation: Graduate School on Electrical Engineering and Applied Computer Science, Federal University of Technology-Paraná (UTFPR), Curitiba-PR 80230-901, Brazil. danielpipa@utfpr.edu.br.
authors.forename: Daniel Rodrigues
authors.initials: DR
authors.lastname: Pipa
authors.affiliation: Graduate School on Electrical Engineering and Applied Computer Science, Federal University of Technology-Paraná (UTFPR), Curitiba-PR 80230-901, Brazil. neves@utfpr.edu.br.
authors.forename: Flávio
authors.initials: F
authors.lastname: Neves Junior
authors.affiliation: Graduate School on Electrical Engineering and Applied Computer Science, Federal University of Technology-Paraná (UTFPR), Curitiba-PR 80230-901, Brazil. lvrarruda@utfpr.edu.br.
authors.forename: Lúcia Valéria Ramos
authors.initials: LV
authors.lastname: de Arruda
authors.affiliation: Graduate School on Electrical Engineering and Applied Computer Science, Federal University of Technology-Paraná (UTFPR), Curitiba-PR 80230-901, Brazil. marcelozibetti@utfpr.edu.br.
authors.forename: Marcelo Victor Wüst
authors.initials: MV
authors.lastname: Zibetti