JPH069621Y2 - STC signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention, for example, controls the gain of a receiver that radiates ultrasonic waves deep inside the subject and receives reflected signals from tissues and tissue boundaries of internal organs. And an STC signal generator used in.

[Prior Art] Ultrasonic waves are radiated into a living body as a subject, ultrasonic reflected signals from tissues and tissue boundaries of various internal organs in the living body are received, ultrasonic diagnostic image display is performed, and the shape of each internal organ is displayed. In the case of performing medical diagnosis of changes in size and tissue, attenuation and scattering of ultrasonic waves occur in in-vivo tissue, and in particular, attenuation during ultrasonic wave propagation by body tissue depends on its frequency and With the increase, the high frequency attenuation of the ultrasonic pulse is remarkable, and the center frequency of the received signal shifts to the low frequency region.

The attenuation coefficient α of the ultrasonic wave of the living tissue is proportional to the frequency. α
= Α ₀ ·, α ₀ : constant ,: frequency, the subject usually has the same basic structure of a living tissue, but since the size and weight of each subject are different, the sizes of organs and tissues are also different.

Since in-vivo tissue is composed of various tissues, the in-vivo sound velocity is not uniform, and when the tissue penetrates, waves of various phases are generated, and the received amplitude becomes small depending on the frequency, and apparent attenuation occurs. growing.

In addition, the reflection signal from the deep part in the living body has a large propagation distance, so that the attenuation becomes remarkable, and in order to make the receiver output signal level uniform, the effective range in which the ultrasonic wave propagates is divided into a plurality of divisions, and each division An STC adjuster is provided individually to compensate the attenuation of ultrasonic signals in each section.
Gain control of the receiver is performed using the signal from the regulator.

The selection of the STC adjuster for each section is performed sequentially according to the elapsed time in synchronization with the timing of ultrasonic wave emission.
The output signal of the regulator is applied to the receiver.

However, the STC adjuster output signal may be output from the receiver due to inductive interference such as power supply, other noise, and internal clock signal.
The STC signal, which has been subjected to the moving average processing of the TC adjuster output signal to reduce the influence of inductive disturbance, is added to the receiver for gain control.

Also, when switching the STC regulator at a high speed, a transient response at the time of switching occurs in the output of the receiver.

[Problems to be Solved by the Invention] The conventional STC signal generator is configured as described above, and the reception gain characteristic of the receiver is such that the size and weight of the living body as the subject are measured so that the ultrasonic diagnostic image can be displayed clearly. Determined by
The STC adjusters are individually adjusted accordingly. The STC adjusters are selected sequentially according to the time elapsed from the timing of ultrasonic emission and the signal is applied to the receiver for gain control.

A transient response at the time of switching operation occurs in the selected STC signal, and when the STC signal is quantized and converted into a digital signal, the operation start timing of the A / D circuit is correct unless the above transient response time is avoided. I can't get the value.

In addition, the STC adjuster output signal is subjected to moving averaging processing to obtain
When used as a TC signal, sampling data by n-circuit scanning is wheeled, and the number of buffer circuits is increased due to the averaging processing. When hardware is used, the number of parts is increased, and when software is used, the number of processing steps is increased and processing is performed. Slow down. In particular, when the STC adjuster is largely changed, it takes a long time to obtain correct digital data, and the response is deteriorated.

The present invention has been made in order to solve such a problem, and an adjusting device is provided for each of the sections divided in the ultrasonic wave propagation direction, and the receiver gain is controlled by the STC adjusting device adjusted according to the subject. Is excellent in response when there is no change in gain or when there is a large change in gain, and when there is influence of inductive interference such as noise or internal clock, the signal is properly discriminated and the correct receiver by the STC adjuster is used. It is an object of the present invention to obtain an STC signal generator capable of controlling the gain of the.

[Means for Solving the Problems] An STC signal generator according to the present invention is an STC in which STC data for controlling a gain of a receiver is stored in each section.
Pattern memory, detection means for comparing the STC regulator output selected in relation to the timing of ultrasonic radiation with the STC data selected from the STC pattern memory, and detecting the deviation, and a deviation from the detection means Comparing means for comparing the quantity and the threshold value of the unit signal level, coefficient means for coefficient of the frequency of continuous output of the comparing means, and a signal when the cumulative value by the coefficient means exceeds a predetermined value. And a control means for instructing the update of the STC data of the STC pattern storage unit by the output of the determination means, and the gain of the receiver is controlled by the STC data from the STC pattern storage unit.

[Action]

In this invention, S for controlling the gain of the receiver is used.
The TC data is stored in the STC pattern storage unit for each section, and the STC adjuster output that is sequentially selected in synchronization with the ultrasonic emission timing in the ultrasonic diagnostic image display is ST
When the deviation is detected together with the STC data in the C pattern memory and the deviation is detected, the comparing means determines the deviation amount, and the counting means accumulates the frequency at which the comparison output continuously occurs. It

When the cumulative value reaches a predetermined value, it is determined that the STC adjuster has been adjusted and the STC signal has changed, and the STC data update command is issued. Therefore, the change in the STC signal can be distinguished from the inductive disturbance due to the intermittent signal such as the noise or the internal clock signal.

When there is no change in the output of the detecting means, there is no update of the STC data. When there is a change in the comparing means that exceeds the threshold value, a data update command is immediately issued and the gain of the receiver is changed from the STC adjuster. It is controlled by following changes in the STC signal at high speed.

[Embodiment] An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the overall configuration of the present invention, showing an example in which there are two types of deviation amounts. In the figure, 1 is an STC adjuster provided for each section divided in the ultrasonic wave propagation direction, 3 Is an A / D circuit, 8 is an STC pattern memory for storing the STC data adjusted by the STC adjuster 1, 1
1 is a receiver whose gain is controlled by the STC data from the STC pattern memory 8, and 18 is the STC pattern memory 8
Detecting means for detecting a deviation between the STC data stored in the STC controller 1 and the output of the STC adjuster 1, and 19 is a first judging means for judging the magnitude of the deviation from the detecting means 18 using a quantization unit, for example, 1 digit as a threshold value. , 20 is a second discriminating means for making the threshold value twice the quantization unit, that is, for example, 2 digits, 21-2, 21-2 are comparing means for discriminating the magnitude of the deviation from the detecting means 18, 22-1 , 22-2 are setters for determining the threshold values used in the first discriminating means 19 and the second discriminating means 20 , and 23-1, 23-2 are timings of ultrasonic radiation from the comparing means 21-2, 21-2. At 24-1, 24-2 is a frequency setter, 25-1, 25-2 is a cumulative value of counting means 23-1, 23-2. And the frequency setters 24-1 and 24-2 for comparing and outputting, and 26 is a first judging means 19.
Also, the control means for generating a data update command based on the output of the second determination means 20 and the output of the comparison means 21-2 which exceeds the threshold value are shown.

In the STC signal generator configured as above,
STC adjuster 1 selected at the timing of ultrasonic emission
The STC signal from 1) is quantized by the A / D circuit 3, and is input to the detecting means 18 together with the STC data stored in the STC pattern memory 8 up to the previous time, and its deviation is detected. The detected deviation is the first discrimination means 19 and the second discrimination means.
Added to 20 . The unit of quantization in the A / D circuit 3 is a digit, and this value is the unit of the minimum deviation,
In the first discriminating means 19 , the setter 22-1 is set to a value of 1 digit, for example, and discriminates the deviation amount with 1 digit of the quantization unit as a threshold value. The second discriminating means
In 20 , the setter 22-2 is set to twice the quantization unit, that is, two digits, so that the deviation amount is discriminated using two digits as a threshold value.

For example, when the deviation amount of the output of the detecting means 18 is 1 digit, it is periodically output to the comparing means 21-1 in the first discriminating means 19 , and the cumulative value of consecutive occurrences in the counting means 23-1 is the frequency setter 24-. When it exceeds 1, the discriminating means 25-1 outputs a data update command to the control means 26, and the STC data stored in the STC pattern memory 8 is updated.

The second discriminating means 20 performs the same operation as the first discriminating means 19 except that the set value of the setter is different.

However, when the deviation amount exceeds the 2-digit threshold value of the setter 22-2 in the comparison means 21-2, a direct data update command is added to the control means 26. At this time, the steps of the counting means 23-2 and the judging means 25-2 are omitted, so that the data can be updated at high speed and excellent responsiveness can be obtained.

Of course, when there is no deviation from the detection means 18, the STC adjuster 1
Since there is no change in the signal of, the data is not updated. Therefore, the STC pattern memory 8 always stores the STC data adjusted by the STC adjuster 1 provided for each section.

FIG. 2 is a block diagram showing an embodiment of the present invention. In the figure, 1, 3 and 8 are the same as the above embodiment, and 2 is an S.
Multiplexer for sequentially selecting the TC adjuster 1, 4 a microcomputer, 5 input / output circuits, 6 central processing unit, 7 read-only memory ROM, 8 STC pattern memory consisting of writable and readable memory RAM, 9 Is a clock oscillator that outputs a clock pulse serving as a reference for calculation, and 10 is an STC of the STC pattern memory 8.
STC circuit for receiving data and converting to gain control signal, 11
Indicates a receiver.

In the STC signal generator configured as described above, a living body as a subject is divided into a plurality of sections in the ultrasonic wave propagation direction, and the STC adjuster 1 is provided for each section. The STC adjuster 1 in each section generates an STC signal so that the receiver 11 for compensating the ultrasonic wave propagation loss can obtain a required gain. The STC adjuster 1 is sequentially selected by the multiplexer 2 that operates in synchronization with the timing of ultrasonic radiation and operates according to the in-vivo ultrasonic wave propagation velocity, and at the same time, STC data of the section in the STC pattern memory 8 is selected, Then, the STC data in the STC pattern memory 8 is updated and the gain of the receiver 11 is controlled via the STC circuit 10.

Therefore, when the STC adjuster 1 is scanned and the adjustment position is changed, the STC data is stored in the SC pattern storage unit 8 in the time series at the timing of the clock signal of the clock oscillator 9.
When the deviation is detected by comparing with the TC data, the STC
The data is updated. Therefore, the gain control of the receiver 11 is performed.

FIG. 3 is an explanatory diagram showing an example of quantization of an STC signal containing noise. M, M-1, M + 1 are quantized values of the STC signal, 15 is noise, and 16 is an actual STC signal. When the level change of the STC signal indicating the level and including the noise 15 superimposed on the STC signal level 16 is within step M of the quantization unit, there is no influence on the quantized data, so the STC pattern storage No data update command is issued to the container 8.

However, when the STC signal level 16 moves up or down within a range not exceeding Step M, the STC signal level 16
The noise 15-1 superimposed on -1 may exceed step M.

When this is quantized, its value M-1 and M or M and M +
It will change over the binary value of 1.

Therefore, when a change of three values or more occurs, it can be determined that the change is due to an artificial operation, and thus the change of the signal is determined to be due to the operation of the STC adjuster 1. That is, the second discriminating means 2
At 0 , when the deviation amount is 2 digits or more of the threshold value, a command for data update is directly issued to the control means 26, so that responsiveness can be realized in real time.

FIG. 4 is a flow chart showing an example of this invention and the operation according to the flow chart.

The STC adjusters 1 are sequentially selected and the STC signal digital data of each adjuster is read.

The selection data A this time and the reference data B up to the previous time are compared for each individual adjuster. That is, AB = θ.

Judgment of the result of the detection by the detecting means 18, no change is detected when θ = 0.

The counters C ₁ and C ₂ become 0, the data in the STC pattern memory 8 is not updated, and the current state is maintained.

Is the deviation amount in the detection means 18 one digit of the quantization unit, that is, θ = 1?

When θ = 1, a counting unit for counting the cumulative value of the frequencies that continuously occur in the STC adjuster.

Whether the cumulative value in the counting means 23-1 exceeds a predetermined value N ₁ or C ₁ > N ₁ . If NO, the data is not updated and C ₁
Leave the process while holding. If yes, go to.

 The data stored in the STC pattern memory 8 is updated.

The counters C ₁ and C ₂ are zero.

Whether the deviation amount in the detecting means 18 is two digits of the quantization unit, that is, θ = 2.

When θ = 2, a counting unit for counting the cumulative value of the frequencies that continuously occur for the STC adjuster 1.

Whether the cumulative value in the counting means 23-2 exceeds a predetermined value N ₂ , or C ₂ > N ₂ . If NO, the data is not updated and the process is exited while holding C ₂ . If yes, go to.

 The data stored in the STC pattern memory 8 is updated.

The counters C ₁ and C ₂ are zero.

When the deviation amount in the comparison means 21-2 becomes 2 digits or more, the data stored in the STC pattern memory 8 is updated.

The counters C ₁ and C ₂ are zero.

As described above, the output of the STC regulator 1 provided in plurals is constantly inspected. When the STC adjuster 1 is operated and the STC signal changes, the STC data stored in the STC pattern memory 8 is compared with the STC data up to the previous time and the detection result of the detecting means 18 is checked by the multiplexer 2 every scanning. Will be updated.

Therefore, even if an inductive interference such as a noise or a clock pulse that interferes with the STC adjuster 1 at one time is added, it does not occur a predetermined number of times n or more in succession, and therefore it is not determined that the output of the STC adjuster 1 has changed.

In addition, it can be distinguished from inductive interference due to noise or random signals, and these effects can be avoided.

The present invention has no way of performing moving averaging processing of the output signal even if noise or inductive interference due to a random signal is added to the output of the STC adjuster 1. Therefore, a buffer or an average for holding n scan data is provided. Since the processing time for the digitization processing is not required, when the amount of change in the output of the detecting means 18 is 0 or when the amount of change is large, for example, 2 digits or more, the data is updated immediately and the response is good and the processing is performed in real time. be able to. In particular, it is important that the response is excellent when the receiver gain control is performed with the STC signals obtained by selecting a plurality of STC adjusters 1 at high speed.

[Effects of the Invention] As described above, the present invention compares the output of the STC adjuster provided for each section divided in the ultrasonic wave propagation direction with the previous STC data each time scanning is performed, and detects the deviation and the detection result. The simple structure provided with the counting means for counting the cumulative value of consecutive occurrences and the judging means detects that the STC signal changes continuously for a predetermined number of times or more, and outputs the STC by the output of the STC adjuster.
The STC data stored in the pattern memory is updated.

Therefore, it is possible to determine the change of the STC signal due to the artificial adjustment of the STC adjuster and the influence of the induction disturbance, so that the signal processing for removing the induction noise is simplified, and the output of the STC adjuster does not need to be subjected to the moving average processing.

In addition, there is no occurrence of transient response when the STC adjuster is selected, no increase in the number of parts of the buffer or hardware for holding data for averaging processing, no increase in the number of processing steps, and no decrease in processing speed. Since the signal can be distinguished from the signal, it is possible to control the receiver gain that correctly follows the STC adjuster.

With a simple configuration, it is possible to correctly determine even a large signal change of a plurality of adjusters, the data is immediately updated, and the gain control of the receiver can be performed in real time.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, FIG. 3 is an explanatory diagram showing quantization of a STC signal containing noise, and FIG. Is a flow chart showing an example of this device. In the figure, 1 is an STC adjuster, 2 is a multiplexer,
3 is an A / D circuit, 4 is a microcomputer, 5 is an input / output circuit, 6 is a central processing unit, 7 is a ROM, 8 is an STC pattern memory, 9 is a clock oscillator, 10 is an STC circuit, 11 is a receiver, Reference numeral 18 is a detecting means, 19 is a first discriminating means, 20 is a second discriminating means, 21-1, 21-2 are comparing means, 22-1,
22-2 is a setting device, 23-1, 23-2 are counting means, 24-1, 24-2 are frequency setting devices, 25-1, 25-2 are determination means, and 26 is a control means. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] 1. An STC signal generator for controlling the gain of a receiver by dividing the inside of a subject in an ultrasonic wave propagation direction and sequentially selecting STC adjusters individually provided for each divided section. STC pattern memory for storing STC data for controlling the gain of the machine for each section, the STC adjuster output selected in relation to the timing of ultrasonic radiation, and the S
Detecting means for comparing the STC data selected from the TC pattern memory to detect the deviation thereof, comparing means for comparing the deviation amount from the detecting means with a threshold value of the unit signal level, and the comparing means. Coefficient means for factoring the frequency of continuous output, determining means for outputting a signal when the cumulative value by the coefficient means exceeds a predetermined value, and updating the STC data of the STC pattern memory by the output of the determining means. The STC signal generator is characterized in that the gain of the receiver is controlled by the STC data from the STC pattern storage unit.