| 摘要 |
PURPOSE:To provide exact blood circulation data by efficiently removing a signal component caused by a biological tissue by controlling the coefficient of an MTI filter for calculating the velocity of the biological tissue based on a Doppler shift signal and for removing the Doppler shift signal caused by the biological tissue from the Doppler shift signal. CONSTITUTION:At a velocity arithmetic part 16, average velocity is calculated from the Doppler shift signals from A/D converting circuits 13, and 14, at an MTI coefficient table 20, the cut-off frequency of the MTI filter optimum for removing the signal from the biological tissue is selected based on the compared result of a comparator 18 and the average velocity due to the velocity arithmetic part 16, and the MTI coefficient is inputted to an MTI filter 17. The MTI filter 17 performs the filtering processing of the Doppler shift signals provided from the A/D converting circuits 13 and 14 based on the MTI coefficient provided from the MTI coefficient table 20. The output of the MTI filter 17 is inputted to a color flow mapping processing part 21, and color flow data are calculated. |
