JPH0222655B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention transmits and receives ultrasonic waves of multiple frequencies simultaneously from each transducer, and passes the received waves through filters having respective frequency bands. , relates to an ultrasonic diagnostic apparatus that displays a plurality of separated B-mode images in a composite manner on a screen.

[Conventional technology and problems]

When transmitting and receiving ultrasonic waves of multiple frequencies, the delay time of the transmitting filter and receiving filter differs depending on each frequency, so when the multiple B-mode images obtained are synthesized, a positional shift occurs between the images. It was hot. For example, as shown in FIG. 5, when transducer A transmits and receives at frequency A, point P is delayed from transducer A to L _A by a delay time τ _A
If transducer B transmits and receives at frequency B, point P is determined to be far away.
is determined to be located farther from transducer B than L _B by delay time τ _B . Therefore, the positional information regarding point P will be different between transducers A and B, resulting in image shift when combining them as a B-mode image.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional drawbacks, it is an object of the present invention to provide an ultrasonic diagnostic apparatus that can produce a final B-mode composite image that is clear and free of deviation.

[Structure of the invention]

Therefore, the first invention of the present invention is
In an ultrasonic diagnostic apparatus that obtains real-time compound images using a plurality of frequency bands, an ultrasonic transducer, a first filter circuit that provides a signal of a predetermined frequency of a trigger pulse to the transducer, and the first filter A delay circuit that delays a trigger pulse input to the circuit, a second filter circuit that passes a signal of a predetermined frequency among the transducer outputs, an AD converter that converts the analog output from the second filter circuit into a digital signal, It has a plurality of channels consisting of an address determining circuit that generates an address specifying a write position in the frame memory in response to input of a trigger pulse, and further includes a trigger pulse source that outputs the trigger pulse, and an output of each of the AD converters. The present invention is characterized by having a frame memory in which a value is written to an address designated by a corresponding address determination circuit, and a display device for displaying the contents of the frame memory.

A second aspect of the present invention is an ultrasonic diagnostic apparatus that obtains a real-time compound image using a plurality of frequency bands, in which an ultrasonic transducer transmits a signal of a predetermined frequency of a trigger pulse to the transducer. a first filter circuit for applying to the user; a second filter circuit for passing a signal of a predetermined frequency among the transducer outputs;
An AD converter that converts the analog output from the filter circuit into a digital signal, an address determination circuit that generates an address that specifies the write position of the frame memory in response to the input of a trigger pulse, and a trigger pulse that is input to the address determination circuit. A trigger pulse source that outputs the trigger pulse, a frame memory that writes the output value of each AD converter to an address designated by a corresponding address determination circuit, and The present invention is characterized by having a display device that displays the contents of the frame memory.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a first embodiment of the present invention, and FIG. 2 is a diagram illustrating the relationship between delay times in the first embodiment.

In the figure, 1a is a first filter circuit that provides a predetermined frequency signal of a trigger pulse to transducer 3a, 2a is a second filter circuit that passes a predetermined frequency signal from the output of transducer A, and 3a is a transmitter/receiver of ultrasonic waves. 4a is an address determining circuit that starts with a trigger pulse, 7a is an AD converter that AD converts the output of the second filter circuit, and 8a is a delay circuit that delays the trigger pulse for a predetermined time. Channel B also has the same configuration as channel A as described above. 5 is a frame memory into which the output value of the second filter circuit corresponding to the address designated by the address determination circuit is written; 6 is a display device that displays the contents of the frame memory.

Now, if the delay time caused by the first filter circuit 1a and the second filter circuit 2a is τ _A , and the delay time caused by the first filter circuit 1b and the second filter circuit 2b is τ _B , then the delay time caused by the first filter circuit 1a and the second filter circuit 2a is τ B. If there is a reflection point P at the same distance from both, the outputs of the transducer E A , E _B as shown by the broken lines in FIG. 2 without the delay circuits 8 a and 8 _b .
is shifted by the delay time difference. Therefore, the delay circuit 8 that provides delay time τ _B to channel A
When a delay circuit 8b is provided to give a delay time τ _A to channel B, the received signals return at the same time as shown by the solid line in FIG.

FIG. 3 is a diagram showing the configuration of a second embodiment of the present invention, and FIG. 4 is a diagram illustrating the relationship between delay times in the second embodiment.

In the figure, 9a is a delay circuit that delays the trigger pulse of the address determining circuit 4a, and 9b is a similar delay circuit in the B channel.

As shown in Fig. 4, the received signals E _A and E _B have a time difference due to the delay time difference of the filter circuit.
The trigger pulse of each address determination circuit 4a, 4b which specifies the address of the frame memory 5 is
By delaying channel A by τ _A and delaying channel B by τ _B , the time series written to the frame memory 5 has a peak at the same time for channels A and B. For this purpose, a delay circuit 9a is inserted before the address determining circuit 4a in the A channel, and a delay circuit 9b is inserted before the address determining circuit 4b in the B channel.

[Effects of the Invention] As described above in detail, the ultrasonic diagnostic apparatus of the present invention can make the finally obtained B-mode composite image clear and free of deviation.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a first embodiment of the present invention,
FIG. 2 is a time chart for explaining the delay time in the first embodiment, FIG. 3 is a diagram showing the configuration of the second embodiment of the present invention, and FIG. 4 is a diagram for explaining the delay time in the second embodiment. FIG. 5 is a time chart for explaining that a difference in delay time causes a shift in a composite image. 1a, 1b...first filter circuit, 2a, 2
b...Second filter circuit, 3a, 3b...Transducer, 4a, 4b...Address determination circuit, 5...Frame memory, 6...Display device, 7
a, 7b...AD converter, 8a, 8b, 9a, 9
b...Delay circuit.

Claims (1)

[Scope of Claims] 1. In an ultrasonic diagnostic apparatus that obtains real-time compound images using a plurality of frequency bands, an ultrasonic transducer; a filter circuit, a delay circuit that delays a trigger pulse input to the first filter circuit, a second filter circuit that passes a signal of a predetermined frequency among the transducer outputs, and converts the analog output from the second filter circuit into a digital signal. a trigger pulse source that outputs the trigger pulse; Each AD mentioned above
An ultrasonic diagnostic apparatus comprising a frame memory in which an output value of a converter is written to an address specified by a corresponding address determination circuit, and a display device that displays the contents of the frame memory. 2. In an ultrasonic diagnostic apparatus that obtains real-time compound images using a plurality of frequency bands, an ultrasonic transducer, a first filter circuit that provides a signal of a predetermined frequency of a trigger pulse to the transducer, and a transducer. A second filter circuit that passes a signal of a predetermined frequency among the outputs, an AD converter that converts the analog output from the second filter circuit into a digital signal, and an address that specifies the write position of the frame memory in response to input of a trigger pulse. It has a plurality of channels consisting of an address determination circuit that generates an address determination circuit, a delay circuit that delays a trigger pulse input to the address determination circuit, a trigger pulse source that outputs the trigger pulse, and an output of each of the AD converters. An ultrasonic diagnostic apparatus comprising a frame memory in which a value is written to an address designated by a corresponding address determination circuit, and a display device that displays the contents of the frame memory.