JP2778743B2 - Ultrasound diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention scans a probe composed of, for example, a plurality of ultrasonic transducers while moving the probe while moving the probe. The present invention relates to an ultrasonic diagnostic apparatus for reconstructing an acoustic image, and more particularly to an improvement in an ultrasonic diagnostic apparatus that uses a D / A converter to arbitrarily weight a received echo from each ultrasonic transducer of a probe.

(Prior Art) Conventionally, when an ultrasonic diagnostic apparatus of this type amplifies a reception echo from each ultrasonic transducer of a probe with a corresponding preamplifier, it obtains a gain control signal of each preamplifier. D /
Using an A converter, this D / A converter
By arbitrarily weighting the above-mentioned received echo with sufficient quantization of bits (256 gradations), it is possible to avoid the saturation of the received echo in the short-range received sound field, to reduce the side lobe and to improve the beam width of the main beam The receiving sound field was improved as follows.

(Problems to be Solved by the Invention) However, in the conventional case, since the avoidance of the reception echo saturation and the improvement of the reception sound field are non-separable, weighting control is performed by the D / A converter.
In order to perform desired weighting control, it is unavoidable to increase the storage capacity of a storage means such as a ROM for storing weighting data, and the control system becomes complicated and large in scale.

The present invention has been made in view of such circumstances, and an object of the present invention is to perform control for avoiding saturation of a reception echo in a short-range reception sound field independently of control for improving the reception sound field. An object of the present invention is to provide an ultrasonic diagnostic apparatus.

[Constitution of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention amplifies a received echo obtained by performing transmission and reception by a probe composed of a plurality of ultrasonic transducers. For each amplifier, an analog gain control signal obtained by converting the digitally stored weighting data by a D / A converter is added, and based on the reception echo weighted arbitrarily, an ultrasonic wave for reconstructing an ultrasonic image is obtained. The diagnostic apparatus is characterized in that the diagnostic apparatus includes a signal source for applying a reference voltage to the D / A converter by appropriately changing the D / A converter in accordance with a depth in a biological distance direction.

(Operation) With the configuration of the ultrasonic diagnostic apparatus according to the present invention, the D / A converter that converts the weighting data stored digitally into an analog gain control signal can be provided according to the depth of the received sound field from the signal source. Since an appropriately changed reference voltage can be applied, the analog gain control signal output from the D / A converter is proportional to the product of the weighting data and the reference voltage. Therefore, if the output of the D / A converter changed by the reference voltage is used as a gain control signal of each amplifier for amplifying the reception echo,
The gain of each amplifier can be precisely controlled according to the depth of the receiving sound field to avoid the saturation of the receiving echo in the short-range receiving sound field. Can be independently controlled.

Therefore, if weighting data is used in a D / A converter with the variable reference voltage applied, the weighting data is a weighting dedicated to improving the reception sound field, such as reduction of side lobes and improvement of the main beam. It becomes data, and the data quantity can be small.

Therefore, desired weighting control can be achieved without increasing the storage capacity of a storage means such as a ROM for storing the weighting data, and since the number of data is smaller than in the past, the configuration of the control system is simplified. Can be

Further, even when an ultrasonic image is obtained by the reception dynamic focus method, the weighting data can be variously set and changed in accordance with the depth in the living body distance direction for each reception dynamic focus stage. Adjustment for improving the reception sound field can be performed easily and reliably.

(Embodiment) FIG. 1 is a block diagram showing a circuit configuration of a main part of an ultrasonic diagnostic apparatus according to an embodiment to which the present invention is applied.

In the ultrasonic diagnostic apparatus according to this embodiment, a probe 1 including 96 ultrasonic transducers CH1 to CH96 is driven and controlled by a selection drive unit 2 and transmitted and received between the probe 1 and a subject. I do. When the received echoes received by the ultrasonic transducers CH1 to CH96 of the probe 1 are amplified by the preamplifier group 3 including the preamplifiers PREA1 to PREA96, the weighting control unit 4 is used to control the gain of the preamplifier group 3. Have.

The weighting control unit 4 includes 48 D / A converters (DAC1 to DAC
AC48) 5, PRE-STC generation circuit 6, address generator 7, RO
M8, shift register 9, 48 latch circuits (LATCH1 to LA
TCH48) and an interpolation / rearrangement circuit 11.

Each D / A converter 5 has a PRE-STC generation circuit 6
While receiving the PRE-STC signal from the ROM 8 as a reference voltage, the weighting data from the ROM 8 is received via each latch circuit 10, and the D / A conversion output is sent to the interpolation / reordering circuit 11.

The PRE-STC generation circuit 6 receives an ultrasonic rate signal from a system controller (not shown) and can programmably set the slope of the PRE-STC signal and the initial offset voltage for each repetition scan rate.
The ROM 8 stores the weighting curve function data for reducing the side rope and the weighting curve function data for improving the beam width of the main beam in different memory areas, respectively. The weighting curve function data is read out to each latch circuit 10 in accordance with the read address from the CPU.

The address generator 7 receives a weighting code for selecting each weighting curve function data stored in the ROM 8, a reception dynamic focus switching clock, and a data latch clock from the system controller. The type of the weighting curve function is selected by the upper 3 bits of the weighting code, and data of 48 channels is addressed by the lower 6 bits.

At the same time, the shift register 9 synchronizes the reception dynamic focus switching clock and the data latch clock with each other.
Each of the latch circuits 10
Enable while shifting the CK1 pin sequentially. In this way, the weighting curve function data, which is the weighting data in the channel direction, is sequentially read from the ROM 8,
It is taken into the first stage of each latch circuit 10. After the weighting data is taken into the first stage of all latch circuits 10, a common clock is input to CK2 of each latch circuit 10, and data is simultaneously transferred from the first stage of each latch circuit 10 to the next stage which is the output stage. Is performed, and the output signal of each latch circuit 10 is updated. Each latch circuit 10 (LATCH1 ~
The output signals of the LATCH 48 are input to the corresponding D / A converters (DAC1 to DAC48) 5, and these D / A converters 5 are digital weighted data on a scale determined by a reference voltage applied to the REF terminal. A certain weighting curve function data is converted into an analog weighting signal. The analog weighting signal is provided to the preamplifier group 3 via the interpolation / rearrangement circuit 11, and is used for gain control of the received echo signal for each channel.

The address generation of the ROM 8 by the address generator 7 and the shift register 9 are performed for each reception dynamic focus stage obtained by dividing the period of the ultrasonic rate signal into a plurality.
, The data of the ROM 8 is fetched by the latch circuit 10, the digital weight data is output from the latch circuit 10 in parallel with the channel direction, and the D / A converter 5
The process of converting the digital weighting data into the analog signal by the above is repeated.

Accordingly, the combination of the address generator 7, the ROM 8, the shift register 9, and the respective latch circuits 10 can change the weighting data used in each of the D / A converters 5 according to the depth in the biological distance direction for each reception dynamic focus stage. It will function as control means that can change the setting.

FIG. 2 is a timing chart schematically showing an operation state of each unit in FIG. As shown, clock 1, clock 3, clock 5,... Clock 2N-1 indicated by the falling pulse of the reception dynamic focus clock (dynamic CK) during one rate.
(N is an integer of 2 or more), the shift register 9 outputs enable signals LE1-1, LE2-1, LE3-1,.
8-1 is output. In an even-numbered stage such as clock 2, clock 4, clock 6,... Clock 2N indicated by the rising pulse, an enable signal common to each latch circuit 10 is output.

Therefore, it is the first stage clock terminal of each latch circuit 10.
The CK1 pin is enabled at odd stages of dynamic CK,
The CK2 terminal is enabled at an even stage of the dynamic CK. Thus, the weighting curve function data selected from the ROM 8 is latched by each latch circuit 10 and output to each D / A converter 5. In FIG. 2, LE1-1 to LE48-1 indicate signals shifted by 1 CK at odd-numbered stages.

Accordingly, each D / A converter 5 in a state where the PRE-STC signal of the PRE-STC generation circuit 6 is applied as a reference voltage
, The weighting curve function data selected from ROM8 is sequentially D / A
It is converted and added to the interpolation / rearrangement circuit 11. Then, in this interpolation / rearrangement circuit 11, the D / A
/ A conversion output is gain control signal PRE-STC1 of preamplifier group 3.
Are interpolated and rearranged so that they can be used as .about.PRE-STC96.

As described above, the gain control signal PRE-STC1 of the preamplifier group 3
~ PRE-STC 96 is generated by the weighting control unit 4, so that control for avoiding the saturation of the received echo in the short-range reception sound field can be performed independently of control for improving the reception sound field. This is shown schematically in FIG.

In FIG. 3, V _PRE - _STC shows how the PRE-STC signal PRE-STC generation circuit 6 that applies respectively in correspondence to the dynamic receiving focusing stage for each D / A converter 5. As in the case of this V _PRE - _STC , the gain V is near the body surface where the ultrasonic transducers CH1 to CH96 of the probe are in contact.
, It is possible to avoid saturation of the reception echo in the short-range reception sound field. That is, since there is no attenuation of the ultrasonic wave near the body surface and the reflected echo from the body is strong, the weight determined by the weighting function data in the ROM 8 is multiplied by V _PRE - _STC to control the gain of the preamplifier group 3. , So that the reception echo in the short-range reception sound field can be collected.

As described above, when the saturation of the reception echo in the short-range reception sound field is avoided, the weighting data used in each D / A converter 5 is used to reduce the side lobe stored in the ROM 8 as the weighting data. The curve function data and the weighting curve function data for improving the main beam width mean that the data does not need to consider the saturation of the received echo.

The manner in which the respective weighting curve function data is used is indicated by V _{STC in} FIG. 3, and weighting for reducing the side rope when the depth in the biological distance direction is shallow is performed. In addition, weighting for improving the beam width of the main beam is performed when the depth is deep in the biological distance direction.

When the output signal of the preamplifier group 3 is sent to the image reconstructing unit 12, the ultrasound image is reconstructed in the image reconstructing unit 12, and the reconstructed content is displayed on the display 13.

In the case of such a configuration of the embodiment of the present invention, as described above, the control for avoiding the saturation of the reception echo in the short-range reception sound field is performed independently of the control for improving the reception sound field. The desired weighting control can be performed by each D / A converter 5 without increasing the storage capacity of the ROM 8, so that the configuration of the control system is simplified, and even though the receiving dynamic focus method is used. In addition, it is possible to easily and reliably improve the reception sound field.

[Effects of the Invention] As described above, the ultrasonic diagnostic apparatus of the present invention has a D /
Since the A converter is equipped with a signal source that applies a reference voltage appropriately changed according to the depth in the biological distance direction, the saturation of the reception echo in the short-range reception sound field is independent of the weighting of the reception echo. Can be controlled.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a main part of an ultrasonic diagnostic apparatus according to one embodiment to which the present invention is applied, and FIG. 2 is a schematic view for explaining an operation state of each part in FIG. FIG. 3 is a waveform chart schematically showing a control state in one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Deep probe, 2 ... Selection drive part 3 ... Preamplifier group, 4 ... Weight control part 5 ... D / A converter 6 ... PRE-STC generation circuit 7 ... Address generator, 8 ... ROM 9: Shift register, 10: Latch circuit 11: Interpolation / rearrangement circuit 12: Image reconstruction unit 13: Display

Claims (3)

(57) [Claims] A digitally-stored weighting data is supplied to each amplifier for amplifying a reception echo obtained by transmitting and receiving by a probe comprising a plurality of ultrasonic transducers.
In the ultrasonic diagnostic apparatus that reconstructs an ultrasonic image based on the reception echo having an arbitrary weight added thereto by adding an analog gain control signal converted by a converter, the D / A converter has a biometric distance direction. An ultrasonic diagnostic apparatus, comprising: a signal generation source for applying a reference voltage appropriately changed according to a depth of the ultrasonic diagnostic apparatus. 2. The apparatus according to claim 1, further comprising control means for changing various settings of the weighting data used in said D / A converter in accordance with the depth in the living body distance direction for each reception dynamic focus stage. An ultrasonic diagnostic apparatus as described in the above. 3. The ultrasonic wave according to claim 1, wherein an initial value and an inclination of the reference voltage can be set programmably in accordance with a depth of the received signal in a biological distance direction. Diagnostic device.