JPH053868A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To digitize a filter circuit without enlarging a circuit scale. CONSTITUTION:An ultrasonic reflection signal obtained from a living body is converted to a digital signal by an A/D converter 12, and inputted to one terminal of a digital adder 13 of a filter circuit 11. The digital adder 13 inputs a part which is outputted to the other terminal of the digital adder 13 through a D/A converter 14, a low-pass filter 15 and an addition A/D converter 16. The digital adder 13 adds a digital signal from the addition A/D converter 16 to the digital signal inputted from the A/D converter 12, and outputs it to a post-stage side. In such a way, the whole filter circuit 11 works as a high-pass filter. A DSC converts a passing signal of the filter circuit to a TV scan and outputs it to a display part. An ultrasonic image whose contour is emphasized is displayed on the display part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus having a contour enhancement function.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus of this type obtains a contour-enhanced image by subjecting an ultrasonic wave reflected signal from a living body to high-pass filtering by a filter circuit.

On the other hand, by digitizing each part of the ultrasonic diagnostic apparatus, adjustment is not required, the circuit scale can be reduced, and the reproducibility is improved, which is advantageous in various points. Digitization is in progress.

However, in the conventional ultrasonic diagnostic apparatus, a filter circuit is used, for example, as shown in FIG.
(Finite Impulse Response) type circuit configuration is assumed to be digitalized. The ultrasonic diagnostic apparatus has a sampling cycle of, for example, 50 nsec in order to secure distance resolution to some extent or more.
(20MHz) and high frequency. In this case, the cutoff frequency fc of the high-pass filter is set to a relatively low value, though it depends on the degree of edge enhancement. At this time, for example, if the cutoff frequency fc is 25 kHz, the number of taps is 20 × 10 ^6. / 25 x 10 ³ = 800, which is a huge number. It can be seen that the circuit scale becomes large and the feasibility is poor if the film is simply made into a digitized form.

IIR (Infinite Impulse Response)
In the case of an infinite night impulse response) type circuit configuration, the number of bits increases, the circuit scale also increases, and the feasibility is poor.

[0006]

As described above, in the conventional device, it is difficult to digitize the filter circuit.
Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide an ultrasonic diagnostic apparatus in which a filter circuit is digitized without increasing the circuit scale.

[0007]

In order to achieve the above object, the present invention provides an A / D converter for digitizing an ultrasonic wave reflected signal from a living body and a digital signal output by the A / D converter. A filter circuit for performing high-pass filtering, and an ultrasonic diagnostic apparatus for forming and displaying an edge-enhanced image based on a pass signal of the filter circuit, wherein the filter circuit is provided with an output signal of the A / D converter. Input to the digital adder, a D / A converter for analogizing a part of the output of the digital adder, a low-pass filter for passing the output signal of the D / A converter, and a low-pass filter for the low-pass filter. It is characterized by comprising an adding A / D converter for digitizing a signal passed through the filter and inputting it to the other of the digital adders.

[0008]

The operation of the ultrasonic diagnostic apparatus constructed as above will be described.

A part of the output of the digital adder of the filter circuit passes through the low pass filter and is input to the other of the digital adders. The digital adder adds the digital signal from the adding A / D converter to the digital signal from the A / D converter and outputs the result to the subsequent stage side. As a result, the entire filter circuit functions as a high pass filter. Further, since the low-pass filter passes an analog signal, it can be simply configured with circuit elements such as resistors and capacitors, and thus the filter circuit does not have to be upsized.

[0010]

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

FIG. 1 is a block diagram of the essential parts of a filter circuit 11 in an ultrasonic diagnostic apparatus 10 according to an embodiment of the present invention. This apparatus 10 is connected to the filter circuit 11 shown in FIG. 1, an A / D converter 12 connected to the front stage of the filter circuit 11 for digitizing an ultrasonic wave reflected signal from a living body, and a rear stage side of the filter circuit 11. It also has a DSC (digital scan converter), a display unit, etc., which are not shown.

As shown in FIG. 1, the filter circuit 11 includes a digital adder 13, a D / A converter 14 for converting a part of the digital signal output from the digital adder 13 into an analog signal, and the D / A converter 14. Low pass filter (LP) for filtering the analog signal from the A / A converter 14
F) 15 and an adding A / D converter 16 for converting an analog signal passed through the filter 15 into a digital signal.

The low-pass filter 15 constitutes an RC filter by combining a plurality of resistors and capacitors, for example, and is provided with an analog switch for switching them. Further, the filter 15 is configured so that the degree of edge enhancement of the ultrasonic image can be adjusted by switching the analog switch from the outside to change the filter characteristic. Next, the operation of the embodiment apparatus 10 having the above configuration will be described.

The ultrasonic reflection signal obtained from the living body is A /
The signal is converted into a digital signal by the D converter 12 and input to one of the digital adders 13 of the filter circuit 11. The digital adder 13 inputs a part of the output to the other of the digital adders 13 via the D / A converter 14, the low-pass filter 15, and the adding A / D converter 16.
The digital adder 13 adds the digital signal from the adding A / D converter 16 to the digital signal input from the A / D converter 12, and outputs the result to the subsequent stage side. As a result, the filter circuit 11 as a whole functions as a high-pass filter. The DSC converts the passing signal of the filter circuit 11 into a TV scan and outputs it to the display unit. An ultrasonic image whose contour is emphasized is displayed on the display unit.

According to the apparatus 10 of this embodiment, since the low-pass filter 15 of the filter circuit 11 has a simple structure such as an RC filter, it is possible to prevent the circuit 11 from increasing in size and to digitize the filter circuit. Can be achieved. Further, since the degree of contour enhancement of the ultrasonic image is variable, the diagnostic ability can be improved. The present invention is not limited to the above embodiment, and can be modified within the scope of the invention.

[0016]

According to the present invention described in detail above, since the low-pass filter has a simple structure with circuit elements such as resistors and capacitors, it is possible to prevent the circuit scale from increasing and to digitize the filter circuit. An ultrasonic diagnostic apparatus designed can be provided.

[Brief description of drawings]

FIG. 1 is a main part configuration diagram of a filter circuit in an ultrasonic diagnostic apparatus according to an embodiment of the present invention.

FIG. 2 is a main part configuration diagram of a filter circuit in a conventional ultrasonic diagnostic apparatus.

[Explanation of symbols]

 10 Ultrasonic Diagnostic Device 11 Filter Circuit 12 A / D Converter 13 Digital Adder 14 D / A Converter 15 Low Pass Filter 16 Addition A / D Converter

Claims (1)

Claim: What is claimed is: 1. An A / D converter for digitizing an ultrasonic wave reflected signal from a living body, and a filter circuit for high-pass filtering a digital signal output by the A / D converter. In an ultrasonic diagnostic apparatus that forms and displays an edge-enhanced image based on a passing signal of the filter circuit, the filter circuit includes a digital adder that inputs the output signal of the A / D converter to one side, and A D / A converter for analogizing a part of the output of the digital adder and the D / A
A low pass filter for passing the output signal of the converter, and an adding A / D converter for digitizing the pass signal of the low pass filter and inputting it to the other of the digital adders. An ultrasonic diagnostic apparatus characterized by: