tailieunhanh - Báo cáo hóa học: " Research Article Optimum Detection of Ultrasonic Echoes Applied to the Analysis of the First Layer of a Restored Dome"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Optimum Detection of Ultrasonic Echoes Applied to the Analysis of the First Layer of a Restored Dome | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 26560 10 pages doi 2007 26560 Research Article Optimum Detection of Ultrasonic Echoes Applied to the Analysis of the First Layer of a Restored Dome Luis Vergara Ignacio Bosch Jorge Gosalbez and Addisson Salazar Departamento de Comunicaciones Universidad Politecnica de Valencia 46022 Valencia Spain Received 26 February 2007 Accepted 19 June 2007 Recommended by William Allan Sandham Optimum detection is applied to ultrasonic signals corrupted with significant levels of grain noise. The aim is to enhance the echoes produced by the interface between the first and second layers of a dome to obtain interface traces in echo pulse B-scan mode. This is useful information for the restorer before restoration of the dome paintings. Three optimum detectors are considered matched filter signal gating and prewhitened signal gating. Assumed models and practical limitations of the three optimum detectors are considered. The results obtained in the dome analysis show that prewhitened signal gating outperforms the other two optimum detectors. Copyright 2007 Luis Vergara et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION In 1 the authors have considered the ultrasonic echo pulse technique to help in the analysis of a dome. The first four layers of the dome were respectively mortar cm plaster cm mortar cm and bricks. The work presented in paper 1 was devoted to the problem of determining the state of adhesion of the interface between the third and fourth layers. The depth of such an interface 3 cm and the type of materials mortar-bricks allowed working with a transducer of 1 MHz so that grain noise due to reflections from the micro-grains of the involved materials is not present at .