A multiple-frequency sound beam was realized by radiating a two-frequency sound. The effectiveness of the presented method was demonstrated through actual imaging.

The authors have developed a Doppler-type ground processing method with which a survivor's respiratory penetrating radar (GPR) unit to find survivors buried in houses that variation is detected from a received signal with a low SNR have collapsed in an earthquake or other disaster. The purpose of this that utilizes the statistical properties of the variation. The study is to improve the dynamic range of radar consisting of an array authors confirmed the effectiveness of the processing method antenna so that it can quickly identify far-off survivors under rubble.experimentally with the subject. In this experiment, a towerThe authors focused on time-variable elements from the respiration structure measuring four meters by four meters with an of a survivor awaiting rescue in order to remove clutter components, above-ground height of approximately three meters was such as the rubble. A healthy individual's respiratory frequency construndttrnmt o avero thee mete top varies from 0.2 Hz to 0.5 Hz, so the authors propose a signal constructed to transmit radio waves to the subject from the top processing method to extract these frequency elements in an effective of structure and receive them. The authors have confirmed the manner. The authors also examine the effectiveness of this method effectiveness of the processing method devised, using five experimentally.1.2-GHz antennas (one for transmitting four for receiving the signals). The measured frequency of the subject's respiratory

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We have been studying an underground imaging method using shear-horizontal (SH) waves to detect buried relics and ruins at shallow depths. To improve the underground image, a deconvolution method has been introduced. An exploration experiment was conducted at a test site to confirm the validity of the method. As a result, we confirmed that the processing technique is effective for improvement of underground imaging at extremely shallow subsurfaces within a depth of 10 m.

The authors have developed a multiple frequency imaging system using a multiple resonance transducer (MRT) consisting of 1–3 composite materials with a low mechanical quality factor Q bonded together. The MRT has a structure consisting of thin and thick piezoelectric plates, two matching layers, and a backing layer. This makes it possible to obtain B-mode images of satisfactory resolution using ultrasonic pulses owing to their short duration. In this paper, the vibration property of the MRT derived through equivalent-circuit analysis is first shown. By utilizing the result, an MRT capable of transmitting ultrasonic pulses for generation of the images of biological tissues with satisfactory resolution is designed and prototyped. Setting the prototype transducer in the mechanical sector probe of commercial ultrasonic diagnosis equipment, the speckle reduction effect is demonstrated using images of various phantoms to mimic biological tissues and a human thyroid.