JPH09248303A - Ultrasonic video device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically control the detection sensitivity of a reflection echo for an interested area inside a testee body. SOLUTION: An ROI setting device 14 for setting the interested area to be a diagnosis object on the screen of an image display part 4 is fitted inside a DSC part 3, also a depth gain control curve computing memory 15 for computing, storing and outputting a gain control curve for a beam direction and a depth corresponding to the interested area set in the ROI setting device 14 is set and a gain for each depth inside an ultrasonic wave circuit part 2 is controlled by the gain control curve. Thus, the detection sensitivity of the reflection echo is automatically controlled for the interested area inside the testee body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic imaging apparatus for transmitting and receiving an ultrasonic beam in a subject to obtain a tomographic image of a diagnostic region and displaying the image on an image display unit. The present invention relates to an ultrasonic imaging device capable of automatically controlling echo detection sensitivity.

[0002]

2. Description of the Related Art A conventional ultrasonic imaging apparatus of this type includes a probe for transmitting and receiving an ultrasonic beam to and from a subject and a transmission pulse to the probe to generate an ultrasonic beam. An ultrasonic circuit unit that receives and amplifies the signal of the reflection echo from the diagnosis site and gives a gain for each depth different depending on the arrival time of the reflection echo to further amplify the video signal,
The reflected echo signal from the ultrasonic circuit unit is input and digitized to store the reflected echo signal as an ultrasonic beam scanning sequence, and X, from the ultrasonic beam scanning sequence is stored.
The digital scan converter unit performs Y scanning and scan conversion, and an image display unit that converts an output signal from the digital scan converter unit into a video signal and displays it as an ultrasonic image. Then, in the ultrasonic circuit section, a wave transmission circuit for transmitting a transmission pulse to the probe to generate an ultrasonic beam is provided, and a signal of a reflection echo returning from the diagnostic site is received and amplified. A wave receiving circuit is provided for this purpose, and a depth gain control section for controlling the gain for each depth and the frequency band for the received reflected echo is provided.

As an automatic gain control method in such a conventional ultrasonic imaging apparatus, firstly, there is one that instantaneously controls the gain of reception amplification according to the echo level within a transmission / reception period of one ultrasonic beam. The second method is to control the gain of reception amplification on average according to the density of the ultrasonic image in frame units obtained by scanning the ultrasonic beam.

[0004]

However, in the conventional automatic gain control method in such a conventional ultrasonic imaging apparatus,
In any of the above methods, regardless of the region of interest in the subject to be imaged, the gain of reception amplification is instantly controlled according to the echo level, or averaged according to the density of the ultrasonic image in frame units. Since the gain of the reception amplification has been controlled, the detection sensitivity of the reflected echo in the region of interest in the subject cannot be automatically controlled. Therefore, for example, the gain setting of the apparatus may be changed due to a person who is fat and has low ultrasonic wave permeability, or a case where an ultrasonic wave is easily transmitted like an infant. For this reason, it may not be possible to guarantee a uniform image density distribution of a video device including a probe, and it may not be possible to sufficiently improve image display in the vicinity of the density including a lot of useful information.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an ultrasonic imaging apparatus capable of automatically controlling the detection sensitivity of a reflection echo with respect to a region of interest in a subject by coping with such a problem. To do.

[0006]

In order to achieve the above object, an ultrasonic imaging apparatus according to the present invention includes a probe for transmitting and receiving an ultrasonic beam in a subject, and a transmission pulse for the probe. An ultrasonic circuit unit that transmits and generates an ultrasonic beam, receives and amplifies a signal of a reflected echo from a diagnostic region, and amplifies the signal by giving a gain for each depth different depending on the arrival time of the reflected echo and further processing the video signal. A digital scan converter unit for inputting and digitizing the reflected echo signal from the ultrasonic circuit unit, storing the reflected echo signal as an ultrasonic beam scanning sequence, and performing X, Y scanning and scanning conversion from the ultrasonic beam scanning sequence. And an image display unit that converts the output signal from the digital scan converter unit into a video signal and displays it as an ultrasonic image. In the image device, an ROI setting device for setting a region of interest to be diagnosed on the screen of the image display unit is provided inside the digital scan converter unit, and a beam corresponding to the region of interest set by the ROI setting unit is provided. Calculate gain control curve for direction and depth
A depth gain control curve calculation memory for storing and outputting is provided, and the gain for each depth in the ultrasonic circuit section is controlled by the gain control curve.

[0007]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of an ultrasonic imaging apparatus according to the present invention. This ultrasonic imaging apparatus transmits / receives an ultrasonic beam into / from a subject, obtains a tomographic image of a diagnosis region, and displays it on an image display unit. As shown in FIG. 1, the probe 1 and an ultrasonic circuit are used. 2 and the digital scan converter (hereinafter referred to as "DSC"
3) and an image display unit 4.

The probe 1 transmits / receives an ultrasonic beam to / from the subject. Although not shown in the figure, the probe 1 is a source of ultrasonic waves and also receives a reflected echo. It has a child element. The ultrasonic circuit unit 2 is
A transmission pulse is transmitted to the probe 1 to generate an ultrasonic beam, a signal of a reflection echo from a diagnostic region is received and amplified, and a gain for each different depth is given and amplified according to the arrival time of the reflection echo. Further, it performs video signal processing, and inside thereof, a wave transmission circuit 5, a wave reception circuit 6, a transmission / reception separation circuit 7, a probe switching scanning section 8, a depth gain control section 9, and a video signal processing. And part 10.

The transmitting circuit 5 delays the simultaneous transmission m-channel transmitting pulses forming an ultrasonic beam to send a transmission signal to the probe 1 so that the ultrasonic beam is deflected and focused. Is. The wave receiving circuit 6 inputs and amplifies the reflected echo signal scattered and reflected from the diagnostic region in the subject and received by the probe 1, and corrects the phase difference or delay time difference between the echoes of each channel. Then, the received beams are deflected and focused by adding them. The transmission / reception separation circuit 7 separates the transmission signal from the transmission circuit 5 so as to minimize the influence of the transmission signal on the reception circuit 6 or prevent the reception circuit 6 from being destroyed. Further, the probe switching scanning unit 8 forms a beam by selecting m channels from n transducer elements of the probe 1 or switching to the probe 1 having a different number of transducer elements. The channel is switched to scan the scanning wave beam. Further, the depth gain control unit 9 gives a gain for each depth different depending on the arrival time of the reflected echo received and amplified by the wave receiving circuit 6, and amplifies the gain. It is designed to be controlled. Then, the video signal processing unit 10 performs logarithmic conversion, detection, and
It performs processing such as γ characteristic conversion.

The DSC section 3 is the ultrasonic circuit section 2 described above.
The reflected echo signal is input and digitized to store the reflected echo signal as an ultrasonic beam scanning arrangement, and X, Y scanning and scanning conversion are performed from the ultrasonic beam scanning arrangement. A line memory 11 that stores one or a plurality of echo signals, a scan converter 12 that scan-converts the echo signals stored in the line memory 11 while interpolating the echo signals in accordance with an X, Y two-dimensional display format, and the above-described configurations. And a control circuit 13 for controlling the operation of the elements.

The image display section 4 is the DSC section 3 described above.
The output signal from the device is converted into a video signal and displayed as an ultrasonic image, and is composed of, for example, a CRT.

Here, in the present invention, the ROI setting unit 14 and the depth gain control curve calculation memory 15 are provided inside the DSC unit 3. The ROI setting device 14 sets a region of interest (hereinafter, abbreviated as “ROI”) to be diagnosed on the screen of the image display unit 4. Further, the depth gain control curve calculation memory 15 is
A gain control curve (hereinafter referred to as "TGC") is set for the beam direction and depth corresponding to the ROI set by the ROI setting unit 14.
This is called a "curve" and is calculated, stored and output.
Then, according to the TGC curve obtained in the depth gain control curve calculation memory 15, the gain for each depth is controlled by the depth gain control section 9 in the ultrasonic circuit section 2.

Next, regarding the calculation means of the depth gain control curve in the ultrasonic imaging apparatus having the above configuration,
This will be described with reference to the flowchart of FIG. First, FIG.
In the same manner as in a normal ultrasonic imaging apparatus, the probe 1 and the ultrasonic circuit unit 2 collect reflected echo signals for a diagnostic region of the subject. Then, the collected reflected echo signal is passed through the video signal processing unit 10 to the DSC unit 3
Sent to The sent reflected echo signal is stored in the line memory 11 in the DSC unit 3.

Next, the reflected echo signal read from the line memory 11 is sent to the depth gain control curve calculation memory 15 in the DSC section 3, and this depth gain control curve calculation memory 15 stores the reflected echo signal. Enter the concentration (step A in FIG. 2). On the other hand, in this state, the ROI setting unit 14 sets the ROI for the reflected echo signal stored in the line memory 11. Next, the depth gain control curve calculation memory 15 is the line memory 1
ROI set for one stored reflected echo signal
A portion corresponding to the depth and the beam direction corresponding to is extracted, and a histogram of the level (density) thereof is calculated (step B). Then, the centroid of the appearance frequency distribution of the density is calculated for this histogram (step C), and the average density is calculated (step D).

Next, the difference between the density frequency centroid obtained as described above and the average density is calculated (step E), and the presence or absence of correction is determined by whether the absolute value of this difference is greater than or less than a certain constant value ε. (Step F). When the absolute value of the difference is larger than a certain value ε, the process proceeds to step G and the TGC curve generated by the depth gain control curve calculation memory 15 is corrected. That is, when the appearance frequency distribution of the density is biased to a density higher than the average density, a gain variation is calculated so that the gain at that portion is reduced (step G), and the TGC curve is calculated by the obtained gain variation. The TGC curve is calculated so as to add the correction value to (step H), and the corrected TGC curve is stored in the depth gain control curve calculation memory 15 (step J). The read corrected TGC curve is output to the depth gain control unit 9 in the ultrasonic circuit unit 2, and the depth gain control unit 9 performs gain control using the corrected TGC curve (step K).

Further, when the appearance frequency distribution of the density is biased to a density lower than the average density, a gain variation is calculated so that the gain in that portion is increased (step G), and the obtained gain variation is calculated. Thus, the TGC curve is calculated so as to add the correction value to the TGC curve (step H). The subsequent steps J and K proceed in the same manner as described above. In these cases, in the depth gain control unit 9, the corrected T
Since the gain control is performed by the GC curve, the image is formed with the corrected gain after the next imaging frame, and the image densities are evenly averaged.

On the other hand, when the absolute value of the difference is smaller than a certain value ε, the process jumps from the step F to the subsequent step of the step K, and the image is formed in the same manner as in the conventional case without performing the above correction.

[0018]

Since the present invention is constructed as described above,
An ROI setting unit for setting a region of interest to be diagnosed on the screen of the image display unit is provided inside the DSC unit, and gain control is performed for the beam direction and depth corresponding to the region of interest set by the ROI setting unit. A depth gain control curve calculation memory for calculating / storing and outputting the curve is provided, and by controlling the gain for each depth in the ultrasonic circuit section by this gain control curve, the region of interest in the subject is reflected. Echo detection sensitivity can be automatically controlled. Therefore, for example, even in the case where a person who is fat and has a low ultrasonic wave permeability or an ultrasonic wave is easily transmitted, such as a baby, it is possible to perform imaging without the gain setting of the apparatus being changed. From this, it is possible to guarantee a uniform image density distribution of the video device including the probe, and it is possible to improve the image display near the density containing a lot of useful information.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an ultrasonic imaging apparatus according to the present invention.

FIG. 2 is a flowchart showing a calculation procedure of a depth gain control curve in the ultrasonic imaging apparatus.

[Explanation of symbols]

 1 Probe 2 Ultrasonic Circuit Section 3 DSC Section 4 Image Display Section 5 Transmitting Circuit 6 Receiving Circuit 9 Depth Gain Control Section 10 Video Signal Processing Section 11 Line Memory 12 Scan Converter 13 Control Circuit 14 ROI Setter 15 Depth Gain Control curve calculation memory

Claims (1)

[Claims] 1. A probe that transmits and receives an ultrasonic beam to and from a subject, and a transmission pulse is transmitted to the probe to generate an ultrasonic beam, and a signal of a reflection echo from a diagnostic site is received and amplified. In addition, an ultrasonic circuit section that gives a gain for each depth and amplifies the video signal, which is different depending on the arrival time of the reflected echo, and further inputs the reflected echo signal from the ultrasonic circuit section, digitizes the ultrasonic beam, and scans the ultrasonic beam. A digital scan converter unit for storing the reflected echo signals as a line and for X, Y scanning and scan conversion from the ultrasonic beam scanning line, and an ultrasonic image by converting an output signal from the digital scan converter unit into a video signal. And an image display unit for displaying as an image, the image display unit is provided inside the digital scan converter unit. A ROI setting device for setting a region of interest to be diagnosed on the screen is provided, and a depth gain for calculating and storing and outputting a gain control curve for a beam direction and a depth corresponding to the region of interest set by the ROI setting device. An ultrasonic imaging apparatus, characterized in that a control curve calculation memory is provided, and the gain for each depth in the ultrasonic circuit section is controlled by the gain control curve.