Deconvolution Filtering for the High-Resolution Ultrasonic Pulse-Echo Measurement.

In the ultrasonic pulses-echo measurement system, the deconvolution signal processing enables maximum information to be extracted from the echo signal under the physical restriction of the acoustic propagation loss, thereby realizing significant improvement of the resolution capability. This paper presents the deconvolution filtering technique which satisfies the practical requirements for the mitigation of noise amplification compatible with a simple fast procedure. Specifically, the time domain deconvolution filter is determined in such a way that the second-order moment of the desired response is minimized under the band-limited condition, thereby optimizing the filter coefficient subject to the constraints of the small processing noise. In addition, the envelope detection is incorporated for the removal of the distortion due to the band-limited nature of the signal. Furthermore, the theoretical formula for the range resolutions achievable with this technique is derived. At the end of this paper, results of the evaluation experiments are shown to demonstrate that high-resolution measurement comparable to the theoretical limit is obtained with small processing noise. [ABSTRACT FROM AUTHOR]