Estimation of internal structure and viscoelasticity from mechanical impedance

Hisao Oka, Takahiko Nakamura

Research output: Contribution to journalArticle

3 Citations (Scopus)


Body structure influences tactile sensation and stiffness evaluation. Conversely, this suggests that internal body structure and stiffness can be estimated from the skin surface. This paper deals with an estimation not only of body structure but also of viscoelasticity under the skin surface by using acoustic random vibration (30 to 1000 Hz). This method allows morphological and functional measurement of the interior of the body. The shape and viscoelasticity of internal objects (tumor, simulated by silicone gel) are estimated from the mechanical impedance measured at the surface. The viscoelasticity and effective vibrating radius are calculated from the impedance spectrum and give a relation between the depth and viscoelasticity of the internal object. The experimental silicone gel model includes two internal hemispheric gels, whose stiffness is different from that of the peripheral silicone gel. The 3-D image of the internal hemispheric gel is reconstructed, based on the relation between the depth and the effective vibrating radius. The viscoelasticity of the internal hemispheric gel is also estimated, based on the relation between the depth and the measured viscoelasticity of the silicone gel slope model.

Original languageEnglish
Pages (from-to)31-39
Number of pages9
JournalElectrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi)
Issue number3
Publication statusPublished - Jan 1 1998



  • Body structure
  • Mechanical impedance
  • Silicone gel
  • Tumor
  • Viscoelasticity

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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