| Texto completo | |
| Autor(es): |
Prado, Vander Teixeira
[1]
;
Higuti, Ricardo Tokio
[1]
;
Kitano, Claudio
[1]
;
Martinez-Graullera, Oscar
[2]
Número total de Autores: 4
|
| Afiliação do(s) autor(es): | [1] Univ Estadual Paulista UNESP, Fac Engn Ilha Solteira, Dept Elect Engn, Ilha Solteira, SP - Brazil
[2] CSIC, Inst Tecnol Fis & Informac Leonardo Torres Queved, Madrid - Spain
Número total de Afiliações: 2
|
| Tipo de documento: | Artigo Científico |
| Fonte: | IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL; v. 61, n. 7, p. 1204-1215, JUL 2014. |
| Citações Web of Science: | 4 |
| Resumo | |
A method for reflector detection, based on the instantaneous phase of the aperture data for ultrasonic images, is proposed. The instantaneous phase (IP) image is obtained by replacing the amplitude information by the instantaneous phase in the delay-and-sum (DAS) beamforming. From the analysis of the IP image, a threshold level is defined in terms of the number of signals used for imaging. This threshold is applied to the IP image, resulting in a two-level image which gives a statistical indication of whether the pixels of a region in the image are related to a reflector or noise/artifacts. Because the proposed method uses only the instantaneous phase of the signals, it is less sensitive to attenuation than conventional DAS amplitude images. The point spread function of a 32-element array with half-wavelength pitch at 5 MHz in water is simulated and the reflector is detected for signal-to-noise ratio values larger than -29.6 dB. A phantom and an aluminum plate with artificial defects are tested with the proposed technique, using linear arrays of 64 and 16 elements, respectively. When compared with DAS amplitude images and with two-level images obtained by thresholding the amplitude images using empirical threshold values, the proposed technique reduced artifacts and dead zone, and detected all reflectors, increasing reflectors' detectability and decreasing the occurrence of false indication of reflectors. The proposed technique can be used as additional information for amplitude image analysis, with the advantages that it does not need time-gain compensation and that it considers an objective threshold value. (AU) | |
| Processo FAPESP: | 13/00330-0 - Formação de imagens de estruturas tipo placa com array de transdutores de ultrassom utilizando ondas de Lamb |
| Beneficiário: | Vander Teixeira Prado |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto |
| Processo FAPESP: | 10/16400-0 - Ensaios não-destrutivos por ultrassom de estruturas tipo placa utilizando arrays de transdutores piezelétricos |
| Beneficiário: | Vander Teixeira Prado |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado Direto |
| Processo FAPESP: | 10/02240-0 - Técnicas de ensaios não-destrutivos de estruturas utilizando ondas acústicas guiadas |
| Beneficiário: | Ricardo Tokio Higuti |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |