JP2003010187A - Ultrasonograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent complicatedness of circuit design and restrain increase of digital noise by holding down the increase of number of signal wires even if a multi-bit AD converter is used or a number of receiving channels are provided in order to improve image quality and perform three-dimensional imaging. SOLUTION: This ultrasonograph is provided with one or more means for converting parallel digital signals to a serial signal and transmitting the same.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus for obtaining a tomographic image by digital signal processing. 2. Description of the Related Art In a digital ultrasonic diagnostic apparatus, an A / D converter for converting a received echo signal into digital data is generally of a parallel output type due to sampling speed. At this time, if the number of reception channels of the ultrasonic diagnostic apparatus is m and the output signal of the AD converter is n bits, then m × n signal lines for transmitting the parallel output signal of the AD converter to the phasing circuit are required. This means that the number of digital signal lines increases in proportion to the number of reception channels of the ultrasonic device and the number of bits of the AD converter. In recent years, the number of output bits of an AD converter and the number of reception channels of an ultrasonic diagnostic apparatus tend to increase in order to realize image quality improvement, three-dimensional imaging, and the like. In other words, in circuits after the AD converter, signal lines for transmitting received data tend to have higher densities. This causes problems such as an increase in cost due to the complexity of board design, an increase in the number of pins of the connector between boards, and an increase in noise due to digital signals. Also, the probe and the device are connected by a cable, and the received signal is transmitted as an analog signal. In order to transmit a received signal in an analog form, a coaxial cable has been generally used to prevent noise contamination. Since the coaxial cable has a large capacity, loss and impedance matching have been problems. [0004] The object of the present invention is to provide a multi-bit AD converter or to provide a large number of receiving channels, mainly for the purpose of improving image quality or three-dimensional imaging.
It is an object of the present invention to provide an ultrasonic diagnostic apparatus in which an increase in the number of signal wires is suppressed, complexity of circuit design is prevented, and an increase in digital noise is suppressed. Further, it is an object of the present invention to eliminate a coaxial cable between the probe and the device, and to realize a connection that hardly needs to consider cable loss and impedance matching. [0005] In order to solve the above-mentioned problems, the present invention comprises a plurality of arranged ultrasonic transducers,
An ultrasonic probe connected to the main unit by a cable is provided, and an ultrasonic wave is radiated to the subject from the ultrasonic transducer and a reflected wave from the subject is received by the arranged ultrasonic transducer. A plurality of received signals are obtained, the plurality of received signals are converted into digital signals by a plurality of analog-to-digital converters, and the received signals converted into digital signals are delayed or phase-processed. In an ultrasonic diagnostic apparatus that obtains an ultrasonic beam by adding and combining signal wavefronts and displays a tomographic image, a received signal is converted into a digital signal by the ultrasonic probe, and the output is parallel / serial. It is characterized in that it is converted and connected to the main unit by the cable. Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments of the present invention, components having the same functions are denoted by the same reference numerals, and their repeated description will be omitted. FIG. 1 is a block diagram showing the overall configuration of an ultrasonic diagnostic apparatus for implementing the present invention. In the figure, 1 is a probe that transmits and receives ultrasonic waves, 2 is a variable gain unit that corrects the attenuation of the received echo signal according to the depth and amplifies it according to the input range of the AD converter 3, and 3 is the received echo signal An analog-to-digital (A / D) converter converts the parallel signal output from the A / D converter into a serial signal, transmits the signal, and restores the signal to a parallel signal immediately before the next stage circuit. Signal transmission means. [0008] By the transmission circuit omitted in the figure,
Ultrasonic waves are emitted from the probe 1 into the subject. The emitted ultrasonic waves are reflected inside the subject to become echo signals, received by the probe 1, and converted into electric signals. The echo signal converted to an electric signal is output to the variable gain section.
After the amplitude is adjusted in 2, the signal is converted into a digital signal in the AD converter 3. Where the AD converter
The output signal of No. 3 is transmitted to the digital phasing means 4 as a serial signal by the serial signal transmitting means 100-1.
The digital phasing means 4 forms and outputs an ultrasonic beam as received from a predetermined direction by a built-in delay circuit and an addition circuit. The ultrasonic beam signal formed by the digital phasing means 4 is transmitted to the serial signal transmitting means 100-
Digital image processing circuit 5 as serial signal by 2
Transmitted to The digital image processing circuit 5 performs logarithmic conversion processing, filter processing, γ correction, and the like as preprocessing for imaging the reception beam. Digital image processing circuit
From the data output for each operation of the ultrasonic beam from 5,
The digital scan converter 6 forms image data and outputs the image data in accordance with scanning of the image display device, that is, performs scan conversion between ultrasonic operation and display operation. Reference numeral 7 denotes a display device which converts the image data output from the digital scan converter 6 from a digital signal to a luminance signal and displays the image as an image, and is generally a CRT monitor. Reference numeral 8 denotes a control unit having a central processing unit and the like for directly or indirectly controlling each of the above-mentioned components and transmitting and receiving ultrasonic waves and displaying images. Next, the operation of the apparatus having the above configuration will be briefly described. The probe 1 is brought into contact with the body surface of the examination region of the subject, and after inputting scan parameters such as a transmission focus depth from an operation panel (not shown), an ultrasonic scan start command is input. Then, the control unit 8 controls each unit and starts an ultrasonic scan. First, the control unit 8 outputs a command to select a vibrator in the first transmission, a drive pulse output command, and a command to set a delay time according to the transmission focus depth to a transmission unit (not shown). I do. A drive pulse is supplied to the probe 1 according to these commands. The transducer selected by the transducer selection command in the probe 1 vibrates at a predetermined frequency when a drive pulse is input, and sequentially transmits ultrasonic waves into the subject. [0010] The ultrasonic wave transmitted into the subject is partially reflected on the surface of the tissue or organ in the living body having different acoustic impedance, and is reflected as an echo toward the probe 1. In order to receive this echo, the control unit 8 controls a receiving system. First, when the transmission is completed, the transducer in the probe 1 is switched to the receiving system. At this time, the transducer used for reception is
The selection is made by the control unit 8 according to conditions such as scan parameters input by the operator. Along with the selection of the vibrator switching, the control of the reception delay time for the digital phasing means 4 is performed. With these controls, an echo generated as the ultrasonic wave propagates from a shallow part to a deep part in the subject is received by the probe 1, and the AD converter 3
Is converted into a digital signal. The received echo signal converted to a digital signal is transmitted to a serial signal transmitting means.
According to 100-1, the signal is transmitted to the digital phasing means 4 by a signal line having a smaller number of bits than the output bit number of the AD converter. As a result, the number of wires between the AD converter 3 and the digital phasing means 4 can be reduced, and the board design can be facilitated. In addition, by transmitting a serial signal transmitted by the serial signal transmission unit 100-1 with a smaller amplitude than a parallel signal before serial conversion, it is possible to reduce noise caused by a digital signal. In the digital phasing means 4, the input received echo signal is phased by a reception delay circuit prepared for each channel, and added by an addition circuit. The received echo signal subjected to the phasing addition processing in the digital phasing means 4 is transmitted to the digital image processing circuit 5 as a serial signal by the serial signal transmitting means 100-2 provided separately from the serial signal transmitting means 100-1. Is done. In this serial signal transmission means 100-2, the AD converter 3
It is obvious that the same effect as that of the serial signal transmitting means 100-1 provided between the digital signal phasing means 4 and the digital phasing means 4 can be obtained. The digital image processing circuit 5 to which the received echo signal has been input performs log conversion processing, filter processing, γ correction, etc. on the input echo signal, and outputs the processed signal to the digital scan converter 6. I do.
The digital scan converter 6 stores the input signal in the memory, and, in accordance with the display synchronization signal,
Reads and outputs the stored contents. When the above operation is completed, the control unit 8 changes the transmission / reception direction of the ultrasonic wave for the second time,
The above operation is repeated by sequentially changing the transmission / reception direction of the ultrasonic wave in the third and so on. Next, an example of the configuration of the serial signal transmission means in the present invention will be described with reference to FIG. In the figure, components before the AD converter 3 and components after the digital phasing means 4 are omitted for simplicity of discussion. FIG. 2A shows an example in which the output signal of the AD converter 3 and the input of the digital phasing means 4 are both parallel. In this case, the output signal of the AD converter 3 is converted into a serial signal by the parallel / serial converter 1000 provided immediately near the AD converter 3 and transmitted. Then, the signal is restored to a parallel signal again by the serial / parallel converter 1001 provided in the vicinity of the digital phasing means 4 and is input to the digital phasing means 4. FIG. 2B shows an example in which the output signal of the AD converter 3 is serial and the input of the digital phasing means 4 is parallel. In this case, the parallel / serial converter 1000 provided immediately near the AD converter 3 in FIG. The output signal of the AD converter 3 is restored to a parallel signal by a serial / parallel converter 1001 provided in the vicinity of the digital phasing means 4, and is input to the digital phasing means 4. Here, as a configuration in which the output signal of the AD converter 3 is serialized, a 1-bit AD converter of ΔΣ modulation may be used, but a parallel / serial converter may be provided in a commonly used parallel output IC. FIG. 2C shows an example in which the output signal of the AD converter 3 is parallel and the input of the digital phasing means 4 is serial. In this case, the serial / parallel converter 1001 provided immediately near the digital phasing means 4 in FIG. The output signal of the AD converter 3 is serially converted by a parallel / serial converter 1000 provided immediately near the AD converter 3 and transmitted. Then, it is directly input to the digital phasing means 4. If both the output of the AD converter 3 and the input of the digital phasing means 4 are serial signals, the present invention can be implemented without adding any other signal processing means. Is obvious from the description so far, and the description is omitted. The number of serial signal wires between the parallel / serial converter 1000 and the serial / parallel converter 1001 depends on how many bits of the parallel signal are converted to one serial signal and whether the serial signal is a differential signal. And so on. However, as shown in FIG. 2, for example, when the number of reception channels of the entire apparatus is m and the number of output bits of the AD converter is n, the number is always m × n bits or less. Further, in the ultrasonic diagnostic apparatus, there is a circuit using a parallel digital signal other than the receiving circuit. By using the same configuration for such a circuit, the number of digital signal lines can be further reduced. Further, by using means capable of transmitting the serial signal with an amplitude smaller than the output signal amplitude of the AD converter 3, it is possible to further reduce noise caused by the digital signal. As described above, according to the present invention, it is possible to provide an ultrasonic diagnostic apparatus in which an increase in the number of digital signal wirings is suppressed, a circuit design is prevented from becoming complicated, and an increase in digital noise is suppressed. I can do it. Although the present embodiment has been described on the same device, if the AD converter and the digital phasing means are physically separated, the optical communication may be used as the serial signal transmission means. Also corresponds. Next, a second embodiment of the present invention will be described with reference to FIG. Note that a circuit for transmitting ultrasonic waves is also omitted in FIG. In the present embodiment, the transducer 1 is provided inside the probe 1.
0, a variable gain section 2, an AD converter 3, and a serial signal transmission means 100-1 are incorporated. In the case of a sector type probe, the variable gain unit 2, the AD converter 3, and the serial signal transmission unit 100-1 are built in as many as the number of transducers. Also, in the case of a linear probe that moves the aperture, a transducer selection switch is built in, and the circuit is built in for the transducers that form the bore. Conventionally, each vibrator is connected to the analog circuit of the main body by a thin coaxial cable. By digitizing the received signal in the probe 1, there is no need to use a coaxial cable for connection with the device, and the signal can be realized with a flat cable or the like. When radiation noise is a problem, the entire cable can be shielded together. Since the main body side is the digital phasing means 4, the problems of impedance matching and loss in cables, which were problems in analog signals, are eliminated. Further, since the number of signal lines is reduced by the serial signal means 100-1, connection is also facilitated. As described above, the invention made by the present inventor is:
Although specifically described based on the embodiments of the present invention, the present invention is not limited to the embodiments of the present invention, and it is needless to say that various changes can be made without departing from the gist of the present invention. . As described above, even if a multi-bit AD converter is used or a large number of receiving channels are provided for the purpose of improving image quality or three-dimensional imaging, an increase in the number of signal wirings is suppressed and circuit design is complicated. And an ultrasonic diagnostic apparatus in which digital noise is prevented from increasing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the overall configuration of an ultrasonic diagnostic apparatus according to one embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration example of a serial signal transmission unit according to the present invention. FIG. 3 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to a second embodiment of the present invention. [Explanation of Signs] 1 ... Probe 2 ... Variable gain unit 3 ... AD converter 4 ... Digital phasing means 5 ... Digital image processing circuit 6 ... Digital scan converter 7 ... Display device 8 ... Control unit 10 ... Transducer 100- 1. Serial signal transmission means 100-2 Serial signal transmission means 1000 Parallel / serial converter 1001 Serial / parallel converter

Continuation of front page    F term (reference) 4C301 AA02 CC01 EE04 EE15 EE20                       GB02 GB04 HH16 HH24 HH33                       HH37 HH38 JA01 JA11 JA18                       JB03 JB04 JB11 JB29 JB35                       JB50 KK03 LL04

Claims (1)

Claims: 1. An ultrasonic probe comprising a plurality of ultrasonic transducers arranged and connected to a main body device by a cable, wherein an ultrasonic probe is applied to a subject from the ultrasonic transducer. A plurality of received signals are obtained by radiating sound waves and receiving reflected waves from the object by the arranged ultrasonic transducers, and the plurality of received signals are converted into digital signals by a plurality of analog-to-digital converters. An ultrasonic diagnostic apparatus which delays or phase-processes a received signal converted into a digital signal, adds together the wavefronts of a plurality of received signals, obtains an ultrasonic beam, and displays a tomographic image. An ultrasonic diagnostic apparatus, wherein a received signal is converted into a digital signal by the ultrasonic probe, an output of the ultrasonic probe is converted from parallel to serial, and the ultrasonic probe is connected to a main unit by the cable.