Ultrasonic imaging apparatus and method of controlling delay

摘要

The present invention enables ultrasonic propagation time values after correction of refraction to be calculated in parallel for each receive channel, by using a recurrence relation in the depth direction. Moreover, accumulation of errors can be avoided by using an accurate propagation time value obtained in advance at a reference depth to correct the propagation time value each time the reference depth is reached. For this error correction, the recurrence relation to calculate the propagation time value can be an approximate expression. For example, the propagation time value can be calculated using the inclination of reference propagation time values between reference depths. In an actual circuit, received signals are sequentially stored in a memory, and a receive beam is formed by calculating an address position corresponding to the propagation time value of the ultrasonic wave, and adding the received signals stored in the calculated addresses.

主权项

1. An ultrasonic imaging apparatus comprising:
an ultrasonic receiver having a plurality of receiving elements for receiving ultrasonic waves reflected or generated in an area of a subject through a medium having a sound velocity different from a sound velocity of the area; a receive beam former which forms a receive beam signal by performing delay control on received signals of receive channels corresponding to at least a part of said receiving elements of said ultrasonic receiver, according to a propagation time from a focal point position of the receive beam to said receiving element; and an image processor which generates an image using the receive beam signal, wherein said receive beam former sequentially calculates, for one of the receiving channels, propagation time values for a plurality of focal points by repeating processing for adding a change of propagation time value corresponding to a change amount of depth of focal point to an already calculated propagation time value to determine a propagation time value for a next focal point, wherein the repeat processing can be independently executed for each of said receive channels, and said receive beam former calculates the propagation time values in parallel for at least a part of said receive channels, and said receive beam former calculates the change of propagation time value using a recurrence relation and based on the change amount of depth of focal point, a recurrence parameter ξi=cos θ′ corresponding to the area and a recurrence parameter ηi=cos θ corresponding to the medium, where θ′ and θ are refractive angles of ultrasonic wave from the focal point to a receive channel in the area and medium respectively, and the recurrence parameter ξi and the recurrence parameter ηi being determined by the recurrence relation using the change amount of the depth of focal point, the sound velocity in the area and the sound velocity in the medium.