Hajime Hayashi

Ultrasound medium characteristics measuring apparatus

An apparatus for measuring acoustic characteristic values of a medium by sending ultrasound pulses into the medium and analyzing the reflected waves from the medium. Medium characteristic values are extracted from the reflected waves, and spectrum scalloping is eliminated. The present invention executes the nonlinear filtering process, for example, the median filtering process to the spectrums, applies a model spectrum to the filtered result and thereby facilitates measurement of supressing fluctuation even when a small number of space average samples one used, by obtaining β from such model spectrum.

Ultrasonic diagnosis apparatus for tissue characterization

A diagnosis apparatus for discriminating a property of the tissue to be observed from the reflected ultrasonic wave uses the nature of the fine structure of the tissue, and more practically uses the interval of small reflecting bodies dispersely distributed in the tissue as the parameters. The intervals flucatuate. Therefore, an average value and/or a degree of fluctuation is calculated and is displayed. For obtaining the average interval, a method of using the cepstrum of the received signal or a method of using the self-correlation of the received signal can be used.

Electro-sound transducer eliminating acoustic multi-reflection, and ultrasonic diagnostic apparatus applying it

An ultrasonic diagnostic apparatus protected from multi-reflection of sound echoes. Multi-reflection is avoided by eliminating the reflection from the surface of an electro-sound transducer. This invention eliminates the surface reflection of the transducer by following three methods: (a) changing a direction of each surface of an array of transducer elements to direct the reflected sound wave away from the main direction of the sound beam; (b) applying an acoustic matching layer to a surface of a piezo-electric device of the transducer to cancel out phases of sound waves reflected by the surfaces of the layer and the device; and (c) providing an acoustic matching surface on a front or back face of the piezo-electric device to cancel out phases of sound waves reflected by the surface of the device.

Image Interpolation for Real-Time Compound Dual Sector Scans

Many technical advantages and clinically valuable evaluations have been reported since simultaneous multifrequency ultrasonography was introduced1–2. This newly devised technique enables dual ultrasonic images to be simultaneously obtained. One application of this technique—real-time compound dual sector scanning—offers more valuable information than conventional ultrasonography.

Improved SQUID Magnetometer with an External Feedback Circuit

The large magnetic noise and weak magnetic signal level of the heart and brain in magnetic measurement require that a magnetometer have a wide dynamic range and be highly sensitive. The single-chip digital SQUID magnetometer proposed by Fujirnaki (Fujirnaki, 1988) featured an internal superconducting feedback circuit that made it compact (3.0 mm × 3.5 mm), but its dynamic range was limited by the volume of magnetic flux stored in the superconducting feedback loop.