JP2009095442A - Gain adjustment method and device of ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify the gain adjustment of a display, in the display (velocity display by color) indicating a velocity by color information of an ultrasonic diagnostic apparatus. <P>SOLUTION: This gain adjusting method includes counting the number of times when a signal level of a color velocity display exceeds a predetermined threshold and calculating a frequency exceeding the threshold. The gain is adjusted based on the frequency. At first, a rough adjustment counting section 36 calculates the frequency in a rough adjustment time, and when the frequency is out of a predetermined range, a rough adjustment section 38 adjusts the gain. When the frequency is within the predetermined range, a fine adjustment counting section 40 calculates a frequency when the signal level in a fine adjustment time exceeds the threshold and a fine adjustment section 42 adjusts the gain based on the result. The rough adjustment time is shorter than the fine adjustment time, so that this method can acquire a suitable gain in an early stage. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus having a speed display function in which the speed of an observation target is superimposed on a tomographic image and indicated by color information.

  2. Description of the Related Art There are known ultrasonic diagnostic apparatuses that transmit and receive ultrasonic waves to and from a subject and obtain a tomographic image based on the intensity of a received signal. There is also known an apparatus having a function of obtaining speed information of an observation target based on a Doppler shift of a received signal and superimposing and displaying a color corresponding to the speed on a tomographic image. In this color speed display (hereinafter referred to as color speed display), gain adjustment is manually performed so that speed information is appropriately displayed. Specifically, the gain is adjusted while the probe is separated from the observation target and left in the air. If the gain is excessively large, the entire image is mottled, and if it is excessively small, the necessary speed display is not performed. A technique of gain adjustment in an ultrasonic diagnostic apparatus is described in Patent Document 1 below.

JP 2000-60849 A

  Conventionally, gain adjustment for color speed display has been performed by operating the gain adjustment knob while viewing the display as required by the operator of the apparatus.

  The present invention simplifies gain adjustment operation in color speed display.

  According to the gain adjustment method in the color velocity display of the ultrasonic diagnostic apparatus of the present invention, the frequency at which the signal level of the color information exceeds a predetermined threshold in the first length period is acquired. The gain is adjusted with the first adjustment range based on the above, and the gain adjustment is repeated until the frequency falls within the first range. After the coarse adjustment step, the signal is output in the second length period. A fine adjustment step of obtaining a frequency at which the level exceeds the threshold value, performing gain adjustment with a second adjustment width based on the frequency, and repeating gain adjustment until the frequency falls within the second range; And the second length is longer than the first length with respect to the length of the period for acquiring the frequency, and the second adjustment width is narrower than the first adjustment width with respect to the gain adjustment width.

  Further, the threshold value regarding the frequency acquisition may be a value that is not displayed if the signal level is lower than the threshold value.

  The gain adjusting apparatus for displaying the color velocity of the ultrasonic diagnostic apparatus according to the present invention executes the above gain adjusting method by a manual operator that adjusts the gain according to the operation amount of the operator and the operation of the operator. And an automatic operator.

  Furthermore, when the manual operator is operated while the above-described gain adjustment method using the automatic operator is being executed, gain adjustment using the manual operator is executed.

  According to the present invention, it is possible to simplify the gain adjustment of the color velocity display of the ultrasonic diagnostic apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus 10 of the present embodiment. The probe 12 transmits and receives ultrasonic waves to the inside of the subject. The probe 12 is provided with an array transducer composed of a plurality of transducer elements, and a converged ultrasound beam is formed by setting a predetermined delay amount for each ultrasound transmitted from each transducer element. The Further, the transmission beam can be scanned by sequentially changing the delay amount. This delay amount is set by the transmission beam former 4, and the transmitter 16 drives each vibration element according to this set amount. The ultrasonic waves received by the probe 12 are amplified by the receiver 18, and the reception signal for each vibration element is delayed by a predetermined amount by the reception beam former 20, and these are added to form a reception beam. Also in the reception beam, scanning is performed by changing the delay amount.

  A signal from the reception beamformer 20 is sent to the tissue tomographic echo processing unit 22 and the color velocity display processing unit 24. The tissue tomographic echo processing unit 22 generates a tomographic image signal based on the intensity of the received signal. For one ultrasonic beam, the depth at which the echo intensity is high is displayed with high luminance, and the depth at which the echo intensity is low is displayed with low luminance. The color speed display processing unit 24 obtains the Doppler shift frequency of the received signal and obtains speed information of the observation target based on this. A color speed signal with color information is generated for this speed. For example, the direction toward the probe 12 is displayed in red, the direction away from the probe 12 is displayed in blue, and the absolute value thereof can be expressed by changing the luminance or the like. The tomographic image signal from the tissue tomographic echo processing unit 22 and the color velocity signal from the color velocity display processing unit 24 are sent to an image forming circuit 26 such as a digital scan converter and displayed on the display 28 based on these image signals. Image information is formed.

  The color speed display processing unit 24 includes a color speed display signal generation unit 30 that generates an original signal of the color speed signal, and a gain adjustment unit 32 that adjusts a gain for the original signal. If the gain is too high, unnecessary color speed information saturation occurs on the display screen, and if the gain is too low, necessary information is not displayed. In order to adjust to an appropriate gain, a gain adjusting unit 32 is provided.

  FIG. 2 is a block diagram illustrating a schematic configuration of the gain adjustment unit 32. The gain adjustment unit 32 sends the gain value to the color velocity display signal generation unit based on the gain information from the coarse adjustment unit 38 or the fine adjustment unit 42. The gain value can be set manually or automatically. For automatic setting, a coarse adjustment counting unit 36, a coarse adjustment unit 38, a fine adjustment counting unit 40, and a fine adjustment unit 42 are provided. After the gain is roughly adjusted by the coarse adjustment counting unit 36 and the coarse adjustment unit 38, the fine adjustment is performed by the fine adjustment counting unit 40 and the fine adjustment unit 42.

  FIG. 3 is an example of an ultrasonic image. A color velocity display area 46 is superimposed on a part of the tomographic image area 44. Random noise 48 appears in the color speed display area 46. If the gain adjustment is inappropriate, the noise 48 increases and the display is difficult to see.

  FIG. 4 is a diagram showing the signal level of the color velocity display signal corresponding to one ultrasonic beam 50 (see FIG. 3). (A) shows a state where the gain is adjusted low, and (b) shows a state where the gain is increased. The horizontal axis represents the depth on the beam, that is, the distance from the probe, and the vertical axis represents the signal level. The threshold value 52 indicates a value displayed on the display 28 when the color speed display signal exceeds this value. In FIG. 4B, there is a portion where the color speed display signal exceeds the threshold value 52, and this appears as random noise 48 on the display screen. If the gain is too small, necessary information is also displayed as a signal below the threshold value and is not displayed.

  The coarse adjustment counting unit 36 acquires the frequency based on the number of times the color speed display signal exceeds the threshold value 52 during the coarse adjustment period T1. That is, the frequency is obtained by dividing the number of times that the color speed display signal exceeds the threshold value 52 within a certain time by the time. If the frequency does not exceed the predetermined value (N−σ) in the coarse adjustment period T1, the coarse adjustment unit 38 increases the gain value by a predetermined amount. If it exceeds the predetermined value (N + σ), the coarse adjustment unit 38 decreases the gain value by a predetermined amount. This is repeated, and if the frequency at which the color speed display signal exceeds the threshold value 52 enters the range of N ± σ, fine adjustment is executed. N is the frequency of occurrence of random noise that is considered appropriate, and a predetermined value can be set in advance from an empirical rule. Further, the operator of the apparatus may be able to make settings. σ is for determining switching from the coarse adjustment to the fine adjustment, and is a value empirically determined in advance so that the gain adjustment converges early. The fine adjustment is executed by the fine adjustment counting unit 40 and the fine adjustment unit 42. The fine adjustment counting unit 40 counts the number of times that the color speed display signal exceeds the threshold value 52 during the fine adjustment period T2, which is longer than the coarse adjustment period T1, and calculates the frequency. If the frequency is less than the predetermined value N, the fine adjustment unit 42 increases the gain value by a predetermined amount. If the frequency exceeds the predetermined value N, the fine adjustment unit 42 decreases the gain by a predetermined amount. When the elapsed time of automatic gain adjustment elapses a predetermined time, the gain adjustment is terminated.

  Note that the coarse adjustment counting unit 36, the coarse adjustment unit 38, the fine adjustment counting unit 40, the fine adjustment unit 42, and the like constituting the gain adjustment unit 32 are shown corresponding to the functions of these configurations. Can be one arithmetic unit that executes processing corresponding to each function. In other words, the calculation unit functions as each unit described above by executing a predetermined process.

  FIG. 5 is a control flowchart relating to automatic gain adjustment. First, each parameter is initialized (S100). For example, the gain is set to the minimum value of the adjustment range. The elapsed time t1 represents the elapsed time during the coarse adjustment period T1, the elapsed time t2 represents the elapsed time during the fine adjustment period T2, and the elapsed time t3 represents the elapsed time from the start of gain adjustment. To express. These elapsed times t1, t2, and t3 are set to 0 by initialization. Next, during the rough adjustment period T1, the number of times the color speed display signal exceeds the threshold value 52 is counted (S102). When the period T1 elapses (S104), a frequency n1 obtained by dividing the number of times by the coarse adjustment period T1 is calculated and evaluated. This evaluation is performed by comparison with the occurrence frequency (reference frequency) N of the random noise 48 considered appropriate as described above. Actually, it is determined whether the frequency n1 falls within a range of ± σ with respect to the reference frequency N. If the frequency n1 is N−σ or less (S106), the gain value is increased by a predetermined width ΔG1 (S108, S110). If the frequency n1 is not less than N + σ (S112), the gain value is decreased by a predetermined width ΔG1 (S112, S110).

  When the frequency n1 falls within the range of ± σ of the reference frequency N, the fine adjustment period T2 is started. The period T2 is longer than the above-described period T1. During this period T2, the number of times the signal exceeds the threshold value 52 is counted (S114). When the period T2 elapses (S116), the counted number of times is divided by the fine adjustment period T2, the frequency n2 is calculated, and compared with the reference frequency N described above. When the frequency n2 is smaller than the reference frequency N (S118), the gain is increased by a predetermined width ΔG2 (S120, S110), and when larger than the reference frequency N (S122), the gain is decreased by a predetermined width ΔG2 (S124, S110). ). The predetermined width ΔG2 can be the minimum gain adjustment width, and the above-described ΔG1 can also be set to the same value. When the predetermined widths ΔG1 and ΔG2 are different values, ΔG1 is set larger than ΔG2. This is repeated until a predetermined gain adjustment period T3 is reached, and when the period T3 has passed (S126), the automatic gain adjustment process is terminated. It can also be terminated by an input from the operator.

  The coarse adjustment period T1 and the fine adjustment period T2 can be determined based on the heart rate and second. For example, the coarse adjustment period T1 can be 1 heartbeat or 1 second, and the fine adjustment period T2 can be 10 seconds. .

  FIG. 6 is a diagram illustrating a configuration example of an operator for gain adjustment. The gain adjusting operator 60 can be provided on the operation panel of the ultrasonic diagnostic apparatus 10. The gain adjustment operator 60 includes an automatic adjustment switch 62 that takes the form of a pushbutton switch in the center and a manual adjustment dial 64 that takes the form of a jog dial that surrounds the automatic adjustment switch 62. When automatic gain adjustment is desired, the operator presses the automatic adjustment switch 62. Thereby, the automatic adjustment described above is executed. When performing gain adjustment manually, the manual adjustment dial 64 is rotated. The increase / decrease in gain adjustment may correspond to the direction of rotation of the dial. For example, the gain can be increased clockwise and the gain decreased counterclockwise. Further, by operating the manual adjustment dial 64 during the automatic adjustment, the automatic adjustment is discontinued and the manual adjustment can be performed. Further, the automatic adjustment can be automatically executed after the ultrasonic diagnostic apparatus 10 is turned on.

It is a block diagram which shows schematic structure of the ultrasonic diagnosing device of this embodiment. It is a block diagram which shows the function of a gain adjustment part. It is a figure which shows the example of a display of an ultrasonic image. It is a figure which shows the relationship between the signal level of a color velocity display signal, and a gain. It is a flowchart which shows the control which concerns on gain adjustment. It is a figure which shows an example of the operation element for gain adjustment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Ultrasonic diagnostic apparatus, 12 Probe, 24 color velocity display processing part, 28 Display, 32 Gain adjustment part, 36 Coarse adjustment counting part, 38 Coarse adjustment part, 40 Fine adjustment counting part, 42 Fine adjustment part, 60 Gain adjustment operator, 62 automatic adjustment switch, 64 manual adjustment dial.

Claims (4)

A method of adjusting a gain in speed display of an ultrasonic diagnostic apparatus having a speed display function in which a speed of an observation target is superimposed on a tomographic image and indicated by color information based on an ultrasonic signal,
In the period of the first length, the frequency at which the signal level of the color information exceeds a predetermined threshold is acquired, and the gain is adjusted with the first adjustment range based on the frequency, and the frequency is A coarse adjustment step that repeats the gain adjustment until it falls within a range of 1;
After the coarse adjustment step, in the second length period, the frequency at which the signal level exceeds the threshold is acquired, and gain adjustment is performed with the second adjustment range based on the frequency, and the frequency is A fine adjustment step that repeats the gain adjustment until it falls within the range,
Have
Regarding the length of the period for which the frequency is acquired, the second length is longer than the first length,
Regarding the gain adjustment range, the second adjustment range is narrower than the first adjustment range.
A gain adjustment method for an ultrasonic diagnostic apparatus.   The gain adjustment method of the ultrasonic diagnostic apparatus according to claim 1, wherein the threshold value related to frequency acquisition is a value that is not displayed if the signal level is lower than the threshold value. A gain adjustment device that performs gain adjustment in speed display of an ultrasonic diagnostic apparatus having a speed display function that superimposes the speed of an observation target on a tomographic image based on an ultrasonic signal and indicates color information,
A manual operator whose gain is adjusted according to the operation amount of the operator;
An automatic operator that executes the gain adjustment method according to claim 1 by an operation of an operator;
Having
Gain adjustment device.   4. The gain adjusting device for an ultrasonic diagnostic apparatus according to claim 3, wherein when the manual operator is operated when the gain adjusting method according to claim 1 is executed by an automatic operator, manual operation is performed. A gain adjustment device in which gain adjustment is performed by a child.

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