Patent ID: 8104336
Filing Date: 2012-01-31
Classification: G01F

Abstract:
1. An acoustic capacity measurement method for finding capacity of a container under test based on a ratio of pressure changes produced in a reference vessel and the container under test by giving equal alternating capacity changes to the reference vessel and the container under test, the acoustic capacity measurement method comprising: receiving, at a signal processing unit, measured values of pressure changes in the reference vessel and the container under test; a pressure change ratio calculating step of calculating, by the signal processing unit, a ratio between the measured values of pressure changes in the reference vessel and the container under test; a rotation step of calculating, by the signal processing unit, an acoustic admittance component of the container under test by rotating the pressure change ratio calculated in the pressure change ratio calculating step by an angle of θ so that the pressure change ratio will vary at a slope of 1 with respect to changes in a surface area in a complex plane; an oblique coordinate transformation step of transforming, by the signal processing unit, the acoustic admittance component calculated in the rotation step into an oblique coordinate system whose axes are given by an imaginary axis and a straight line with a slope of 1; and a capacity calculating step of calculating, by the signal processing unit, the capacity of the container under test by multiplying values in a direction of the imaginary axis of the acoustic admittance component transformed into oblique coordinates in the oblique coordinate transformation step by a predetermined real number.