JPS6320544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic diagnostic apparatus, and particularly to an echo signal processing apparatus thereof.

In conventional ultrasonic diagnostic equipment, logarithmic amplifiers are used to extend the dynamic range.
FIG. 1 shows a circuit block diagram of such a conventional example. In the figure, 1 is a pulser that generates a transmission impulse, 2 is a transducer that transmits and receives ultrasonic waves, 3 is a preamplifier that amplifies the echo signal, 4 is a main amplifier, and 5 is a logarithmic amplifier that expands the dynamic range. , 6 is an envelope detector for detecting ultrasonic echo signals, 7 is a display control circuit,
8 is a control circuit, and 9 is a CRT display device.

However, in such a conventional device, it is extremely difficult to accurately and stably maintain the input/output characteristic curve of the logarithmic amplifier 5, and therefore it is usually only possible to perform inaccurate corrections, and the input/output characteristic curve is It was impossible for the user to change it arbitrarily.

In view of the above, the present invention aims to provide an ultrasonic diagnostic apparatus in which a conversion curve of input/output characteristics can be arbitrarily set or selected, and whose characteristics are extremely accurate and stable.

To achieve this objective, the present invention does not use a logarithmic amplifier, but converts an echo reception signal into a digital signal by an A-D converter, and then converts the input signal according to data stored in a random access memory in advance. It is characterized in that it is configured to convert the value into a signal having a desired functional relationship corresponding to the value, and to display this signal on an image display device.

Examples of the present invention will be described below.

FIG. 2 shows a circuit block diagram of an embodiment of the present invention. Circuits that are the same as those in FIG. 1 are designated by the same numbers.

The A/D converter 10 converts the analog signal output from the envelope detector 6 into an n-bit digital signal Ai. Random access memory 11 is A
-D converted n-bit digital signal Ai is used as an address, and converted m-bit data Di is written to each address.

This address Ai and conversion data Di can be arbitrarily determined by data generation means, which will be described later.
For example, as shown in FIG. 3, the conversion data Di can be a logarithmic function for Ai, and
As shown in FIG. 4, it can be a logarithmic function with a noise recovery function such that the output is 0 when the input is small. Furthermore, as shown in FIG. 5, it may be linear with a noise reduction function. Generally speaking, the number of m bits can be kept within the dynamic range of the monitor by setting m≦n when the image memory 12 is provided, so the number of bits can be kept within the range that does not affect the image quality. The capacity of the image memory 12 can be saved. Random access memory 1
The read data Di of 1 is again converted into an analog signal by the DA converter 13, and is displayed as an image on the CRT display device 9 via the display control circuit 7 as in the conventional case.

The multiplexer 14 can select either the output of the A-D converter 10 or the output of the converted data generating means 15 and introduce it into the address of the random access memory 11, but during diagnosis, it is always possible to
-The output of the D converter 10 is selected. The conversion data generation means 15 is a read-only memory, a function data calculation device of a computer, or a data input device such as a keyboard, and is a data input device such as a read-only memory, a function data calculation device of a computer, or a keyboard, and converts addresses a _i to output data d as illustrated in FIGS. 3 to 5. generate _i , address a _i to multiplexer 1
4, data d _i is stored in random access memory 1
1.

According to the present invention, all echo signals necessary for diagnosis can be reproduced using arbitrary input/output conversion characteristics, thereby contributing to improvement in diagnosis accuracy. Further, the number of bits of a pixel can be reduced without affecting the image as a pre-processing when using the image memory 12, and the capacity of the image memory 12 can be reduced.

Furthermore, the conventional method using a noise rejection circuit had the disadvantage that the amplitude of the signal was attenuated as well as the noise, but according to the present invention, it is possible to provide the functional relationship as shown in FIG. 4 or FIG. Since it is possible to perform virtual noise elimination, image quality can be improved, and diagnostic accuracy and diagnostic efficiency can be increased.

[Brief explanation of the drawing]

Fig. 1 is a circuit block diagram showing a conventional example, Fig. 2 is a circuit block diagram showing an embodiment of the present invention, Fig. 3,
FIGS. 4 and 5 are diagrams for explaining the relationship between addresses and stored data in the random access memory 11 of FIG. 2. 1...Pulsa, 2...Transducer, 3,
4...Amplifier, 6...Detector, 9...CRT display device, 10...A-D converter, 11...Random access memory, 13...D-A converter.

Claims (1)

[Claims] 1 In a device that diagnoses the condition of a subject by displaying the signal obtained by detecting an echo signal received by a transducer on a monitor image display device, A-D converts the magnitude of the echo signal into a digital quantity. a converter, and a random access memory that receives the digital signal converted by the A-D converter as an address and outputs a digital quantity having a predetermined functional relationship with the input signal value written in advance at each address. , a D-A converter that converts the output of the random access memory into an analog quantity;
A circuit means for introducing the analog signal converted by the D-A converter into the monitor image display device, and a conversion data generation means for writing a predetermined functional relationship in the random access memory, An ultrasonic diagnostic apparatus characterized in that the above functional relationship can be changed arbitrarily by a generating means.