| 摘要 |
PURPOSE:To obtain an ultrasonic tomographic image having no sensitivity difference and good in resolving power even when any focus is set by providing a means automatically setting a focus region where the resolving power of a depth part to be examined is made preferential at the time of one stage focusing selecting only one focus region. CONSTITUTION:Three focuses F1, F2, F3 can be selected by a key switch 1. Now, for example, when the two-stage focus of the focuses F2, F3 is selected by the key switch 1, transmission-reception is required twice in order to form one ultrasonic beam. At the time of the transmission-reception of the second time, when the transmitted wave of the focus F2 of the first time is set to focus data f2' reduced in its caliber as compared with focus data f2 and a change-over point is set to a change-over point A2 slightly behind, beam uniform from an intermediate part to a deep part is can be obtained. As mentioned above, by selecting and setting respective focus regions at the times of one-stage focus and multistage focus, an image having no sensitivity difference and good in resolving power can be obtained. |
