Nihon University

Yoshinobu Murayama

Sadao Omata

Katsuhito Honda

A material hardness distribution display system () includes a probe unit () in which a plurality of probe elements () are two-dimensionally arranged. Each of the probe elements () has an oscillator () for introducing oscillation into a biological tissue and an oscillation detection sensor () which detects a reflected wave. The probe elements () are successively selected by a switch circuit () and connected to a hardness calculation unit () and a measurement depth calculation unit (). The hardness calculation unit () executes a frequency component analysis for an incident wave signal to the oscillator () and a reflected wave signal from the oscillation detection sensor () to calculate the hardness of the biological tissue on the basis of the analysis results. The measurement depth calculation unit () calculates a measurement depth inside the biological tissue at a position where the hardness has been measured, on the basis of a temporal position of the incident wave signal and a temporal position of the reflected wave signal. They are correlated to the respective probe elements ().

Material hardness distribution display system and material hardness distribution display method

In a hardness measurement system, selecting an operating frequency is facilitated by using a phase shift circuit. A hardness sensor is connected to an operating frequency selection apparatus and in a free end state the amplitude versus frequency characteristic is acquired, and the frequency and the phase of the peaks are measured and acquired as the free end characteristic. Next, the hardness sensor is placed into contact with a first test piece, and the frequency and the phase that change for the peaks are measured and acquired as the first characteristic. The same procedure is performed for a second test piece that is harder than the first test piece to yield the second characteristic. Based on these characteristics and a predetermined selection criterion a peak suitable for hardness measurement is selected and the operating frequency is set from the frequency of the peak.

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Tokyo, Japan

Yoshinobu Murayama