| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic photographic method and its device as well as a method for determining variable power thresholds in order to obtain quality images by efficiently eliminating noise from receiving signals and establishing differential power thresholds depending on the position of pixels. SOLUTION: Variable power thresholds are determined depending on the noise, and ultrasonic signals are transmitted to an object by more than one transducer, whereas the first signals whose transmitted ultrasonic signals consists of the signals projected from the object and noise are received, while the ultrasonic images of the object corresponding to the first signals are formed when the electric power of the first signals is larger than the variable power thresholds. |
