Development of the three-dimensional visualization method for the inner structure of small size fish using 25 MHz acoustic profile measurement

摘要

Visualization method using ultrasonic acoustic profile measurement was introduced and inner structures of small size fishes were examined. Detection of external and internal body surface were executed. Two kinds of fishes are chosen in this experiment and measured by using 25 MHz medical probe. Then signal processing and visualization of three-dimensional structure including inner part of the body, abstraction of the skin and organ boundary surface and mapping of reflection signal strength on their surfaces with corrections for surface gradient acoustical loss and scattering attenuation by referring the reflection strength change rate data, relating on the gradient and distance from the probe to target surface. Data for correction was taken from cylindrical silicon model are carried out. Three-dimensional acoustic images are obtained and the result shows that the detection of organs is possible even if these are small size organs of small size fishes. Then the reflection signals from the boundary surface of organs could also be seen clearly. Surface abstraction and reflection strength mapping shows points which has strong hardness and has great change of acoustic impedance. Application for fish species classification by reflection signal amplitude on body surface were tried and its capability was confirmed.