| 摘要 |
PURPOSE:To effectively measure the temporal change of the speed of vector-like movement by time sequentially integrating two-dimensional signals with respect to a specific position. CONSTITUTION:By performing such operations that ultrasonic waves are transmitted and the reflected signals of the ultrasonic waves are received several times with a plurality of elements, the received signals of each element corresponding to distances in a specific direction are found time sequentially. Ordinary one- or two-dimensional Fourier transformation is performed on the found signals. Then the speed of vector-like movement is measured by integrating the two-dimensional signals obtained as a result of the Fourier transformation in a specific direction and time sequentially integrating the obtained two-dimensional signal with respect to a specific position. In addition, ultrasonic waves are generated in an objective area by vibrating part of an array type ultrasonic transducer 19 with a signal from a driving signal source 20. Signals from a reflecting body are inputted to a speed computing element 23 through an amplifier 21 and A/D converter 22. An arithmetic section 23 performs speed measurement processing, such as various kinds of Fourier transformation, integration, etc., and a displaying section 24 displays the processed results. |
