JP3616746B2 - Ultrasonic diagnostic equipment - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a medical ultrasonic diagnostic apparatus.
[0002]
[Prior art]
Conventionally, when acquiring a tomographic image that is the original information of a three-dimensional image, the angular resolution of the encoder signal for oscillation control is low, and it has been difficult to provide a high-precision three-dimensional image. In order to solve this problem, Japanese Patent Application Laid-Open No. 11-178822 discloses a method for improving resolution by adding an integration circuit to an encoder output pulse in order to obtain an angular resolution higher than that inherent in a rotary encoder.
[0003]
In order to solve problems such as difficulty in observing the echo level of the surface of an object when displaying a three-dimensional image, Japanese Patent Laid-Open No. 5-146432 discloses a virtual viewpoint. Means are used such as setting the brightness of the object surface according to the distance, and setting the hue or the like according to the echo level of the object surface.
[0004]
In the case of displaying a three-dimensional image by swinging the ultrasonic probe, it is desired to realize complete equiangular velocity control. However, since a high-speed and high-accuracy control circuit is required, in a general oscillation control circuit, the oscillation encoder pulse width becomes shorter near the center of the amplitude and becomes longer at both ends of the amplitude. have. Therefore, in the method for obtaining an angular resolution higher than the angular resolution originally possessed by the rotary encoder described in the above-mentioned JP-A-11-178822, “a second pulse at a shorter interval is applied based on the first encoder pulse signal. The present invention is applicable to an electronic scanning type ultrasonic probe that can generate and execute the ultrasonic beam scanning control based on the second pulse signal.
[0005]
[Problems to be solved by the invention]
However, in the case of a mechanical sector type ultrasonic probe, since it is premised that the scan for obtaining a tomographic image always rotates at a constant speed, the second pulse width that dynamically changes at each oscillation angle is obtained. There is a problem that it is difficult to dynamically change the rotational speed by matching them without adding a new control circuit.
[0006]
Further, in the technique such as “setting the brightness of the object surface according to the distance from the virtual viewpoint” of the ultrasonic diagnostic apparatus described in Japanese Patent Laid-Open No. 5-146432, the path from the virtual viewpoint to the target object In the case of a general ultrasonic image including a lot of noise, there is a problem that it is difficult to exert an effect normally.
[0007]
The present invention solves the above-described conventional problems, and utilizes the fact that a mechanical sector type ultrasonic probe for acquiring a tomographic image always maintains a physical dimensional accuracy of the tomographic image by rotating at a constant speed. Thus, even when a mechanical sector type ultrasonic probe is swung, an excellent ultrasonic diagnostic apparatus that improves the position information of the swing angle beyond the resolution of the swing encoder and provides a highly accurate three-dimensional image. The purpose is to provide.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, an invention according to claim 1 of the present invention obtains a tomographic image and rotates an ultrasonic element by rotating an ultrasonic element that transmits and receives ultrasonic waves. Means for obtaining a plurality of tomographic image data as original data of a three-dimensional image, means for generating an encoder signal for swing control, means for generating an encoder signal for rotation control, and an encoder for swing control In an ultrasonic diagnostic apparatus having an angle detection circuit to which a signal and an encoder signal for rotation control are input, interpolation using the encoder signal for rotation control is performed on the angular resolution obtained from the encoder signal for oscillation control The ultrasonic diagnostic apparatus is characterized in that an angular resolution of a tomographic image is generated for each tomographic image.
[0009]
With this configuration, when a three-dimensional image is constructed by swinging a mechanical sector type ultrasonic probe without adding a circuit, the angle information of the acquired tomographic image can be detected with high accuracy. An accurate three-dimensional image can be provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
1 and 2 show an ultrasonic diagnostic apparatus according to an embodiment of the present invention.
[0012]
As shown in FIG. 1A, an ultrasonic diagnostic apparatus according to an embodiment of the present invention includes a mechanical sector type three-dimensional ultrasonic probe (hereinafter simply referred to as “probe”) 100, an ultrasonic transmission / reception circuit. 111, a control circuit 112 that stabilizes the rotation speed while receiving the rotation encoder signal of the probe, a circuit circuit 113 that controls the speed and angle of the swing while receiving the swing encoder signal, and an image memory for storing tomographic image data 114, a three-dimensional processing unit 120, an angle detection circuit 121 that generates high-resolution angle information from two encoder signals of rotation and swing, a high-speed arithmetic processing unit 122 that generates three-dimensional image data, a tomographic image and a three-dimensional image Is composed of an image processing circuit 115 for converting to a display format, an observation monitor 116, and a host uP 150 for controlling the entire system. 1A is a side view showing the rotation direction when the probe 100 rotates, and FIG. 1B is a plan view showing the swing range when the probe 100 swings. .
[0013]
Next, the operation of the ultrasonic diagnostic apparatus according to the embodiment of the present invention will be described.
[0014]
The ultrasonic echo signal received by the probe 100 is temporarily stored in the image memory 114 via the transmission / reception unit 111. At this time, for each received echo signal, an encoder signal for oscillation control with a low angular resolution and an encoder signal for rotation control with a high resolution but not directly related to the oscillation angle are respectively connected to a swing control circuit. 113 and the rotation control circuit 112 are input to the angle detection circuit 121 and converted into high-resolution angle information.
[0015]
FIG. 2 shows an example of conversion into high-resolution angle information. In FIG. 2 (a), swinging is started from the center of swinging (swinging midpoint), rightward movement is started, and swinging specified angle is shown. Until the probe tip travels in the opposite direction, proceeds to the opposite swing angle, and then repeats the swing motion of the right and left movements again, and the trajectory generated between them. A diagram showing the generation interval of the encoder pulse for dynamic control and a diagram showing the generation interval of the encoder pulse for rotation control that keeps rotating at a constant speed while swinging are shown so that the relationship can be understood. ing. That is, the oscillation encoder pulse generates a pulse at a short interval because the moving speed is higher at the center of the oscillation, and the pulse interval becomes longer near the both ends where the oscillation angle is reversed, so that the pulse interval becomes long. However, since the encoder pulse for rotation control always continues to rotate at a constant speed, pulses with a constant interval are always generated regardless of the swing position. FIG. 2 (b) is an enlarged view of the relationship of the encoder pulses in the portion a of FIG. 2 (a). Point A and point B are adjacent oscillation encoder pulses, and point Tn is an encoder for rotation control. The reference point of the pulse, α is the distance between the A point and the Tn point (= number of rotation encoder pulses), and β is the distance between the A point and the B point (= rotation encoder pulse number). Therefore, the angle information of the tomographic image data acquired at the Tn reference point can be converted into high-resolution angle information by calculating as follows from the proportional relationship with the number of pulses of the rotary encoder information.
[0016]
Tn = B + (| A-B |) × α ÷ β
However, since the rotation angle information is about 1000 times more accurate than the swing angle information, it is assumed that the swing speed change within a minute angle between A and B can be ignored.
[0017]
Referring again to FIG. 1, high-precision rocking angle information obtained by the angle detection unit 121 of FIG. 1 based on the proportional relationship with the number of pulses of the rotary encoder information is sent to the high-speed arithmetic processing circuit 122, and at the same time, the image memory 114. Since the image data is taken in, a highly accurate three-dimensional image in which highly accurate rocking angle information is included in the three-dimensional image construction is generated. The generated three-dimensional image is sent to the image processing circuit 115, converted into an image format selected by an observer (user), and displayed on the observation monitor 116.
[0018]
Next, FIG. 3 shows a block diagram of another ultrasonic diagnostic apparatus of the present invention.
[0019]
As shown in FIG. 3, another ultrasonic diagnostic apparatus of the present invention includes a mechanical sector type three-dimensional ultrasonic probe (hereinafter simply referred to as “probe”) 200, an ultrasonic transmission / reception circuit 211, and a rotational speed of the probe. The control circuit 212 for stabilizing the image, the image memory 214 for storing the tomographic image data, the three-dimensional processing unit 220, the boundary determination control circuit 221 for changing the parameter for boundary determination according to the distance from the virtual viewpoint, and the three-dimensional image data. A three-dimensional processing circuit 222 to be generated, an image processing circuit 215 for converting to a tomographic image and a three-dimensional image display format, an observation monitor 216, an observer 217 who obtains three-dimensional information from the observation monitor 216, and an observer make a boundary determination. A console 218 for instructing parameter change and a host uP 250 for controlling the entire system.
[0020]
Next, the operation of another ultrasonic diagnostic apparatus of the present invention will be described.
[0021]
The ultrasonic echo signal received by the probe 200 is temporarily stored in the image memory 214 via the transmission / reception circuit 211. In the three-dimensional image generation unit 220, the boundary determination control circuit 221 performs boundary determination based on parameters such as a noise cut value in which the boundary determination control circuit 221 performs boundary determination according to the distance from the default virtual viewpoint from the image data acquired from the image memory 214. The three-dimensional image is generated by the three-dimensional processing circuit 222. The generated three-dimensional image is sent to the image processing circuit 215, converted into an image format selected by the observer (user), and displayed on the observation monitor 216. When the observer 217 inputs the value of a parameter such as noise cut for performing boundary determination while looking at the three-dimensional image displayed on the observation monitor 216 from the console 218, the boundary determination control circuit 221 makes a new boundary determination by the new setting. And the image generated by the three-dimensional processing circuit 222 is displayed on the observation monitor 216 again.
[0022]
With reference to FIG. 4, the case where distance information is not considered in the boundary determination will be described.
[0023]
Using fixed threshold values, the effects of echo signals and noise in each line of sight are shown for line of sight (A), line of sight (B), and line of sight (C). Shows a pattern of becoming NG. That is, in the case of the line of sight (A) and the line of sight (B), the amount of noise that increases in proportion to the distance from the virtual viewpoint reaches the object (the surface) before the threshold value exceeds the threshold value. Therefore, the correct boundary determination is performed. However, in the case of the line of sight (C), the distance from the virtual viewpoint is far (= far), so that the rising noise amount exceeds the threshold value, and then the object (surface) is detected. Since it has reached, the point where the noise amount exceeds the threshold value is determined as the boundary (= the surface of the object), not the actual surface of the object. That is, the boundary determination is NG.
[0024]
Next, a case where distance information is added to the boundary determination will be described with reference to FIG.
[0025]
As an example of changing a parameter such as a noise cut value for performing boundary determination according to the distance from the virtual viewpoint, the line of sight (AA), line of sight (when the threshold is changed according to the distance from the virtual viewpoint) BB) and the effects of the echo signal and noise in each line of sight (CC) are shown, and the boundary determination in the case of performing the three-dimensional calculation is shown. That is, in the case of the line of sight (AA) and line of sight (BB), even when the threshold value is varied, the object increases before the amount of noise that increases in proportion to the distance from the virtual viewpoint exceeds the threshold value. (Surface) has been reached, so the correct boundary determination is performed as in FIG. In particular, in the case of the fixed threshold value in FIG. 4, even when the distance from the virtual viewpoint is far (= far) as in the case of the line of sight (CC) where the boundary determination is NG, the threshold value is set to the distance. Since it rises accordingly, it reaches the object (surface) before the amount of noise becomes greater than or equal to the threshold value, so it is determined that the boundary of the actual object (= surface of the object). That is, boundary determination is performed and a correct three-dimensional image is provided.
[0026]
In addition, when the observer 217 inputs the value of a parameter such as a noise cut for determining the boundary while viewing the three-dimensional image displayed on the observation monitor 216 in FIG. By making settings different from normal values such as values, it is possible to deliberately not display the boundary of a portion far from the virtual viewpoint on the observation monitor 216.
[0027]
【The invention's effect】
As described above, according to the present invention, an ultrasonic element that transmits and receives ultrasonic waves, and a tomographic image is obtained by rotating the ultrasonic element, and the original data of a three-dimensional image is obtained by swinging the ultrasonic element. Data acquisition means for obtaining a plurality of tomographic image data, swing signal generating means for generating an encoder signal for swing control, rotation signal generating means for generating an encoder signal for rotation control, and swing control In an ultrasonic diagnostic apparatus having an angle detection circuit to which an encoder signal and an encoder signal for rotation control are input, interpolation is performed using the encoder signal for rotation control to the angular resolution obtained from the encoder signal for oscillation control By generating the angular resolution of the tomographic image for each tomographic image, the mechanical sector type ultrasonic probe can be swung to add a three-dimensional image without adding a circuit. Upon built, the angle information of the tomographic image obtained can be detected with high accuracy, it is possible to provide an ultrasonic diagnostic apparatus three-dimensional image of high accuracy can be obtained as a result.
[Brief description of the drawings]
1A is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention; FIG. 1B is a plan view showing a swing range when the probe swings; FIG. Explanatory drawing (b) which shows an example which converts the angular resolution in embodiment of this invention with high precision is an enlarged view of a part in FIG. 2 (a). FIG. 3 is a block diagram of another ultrasonic diagnostic apparatus of the present invention. FIG. 4 is an explanatory diagram showing an example when distance information is not taken into account for other boundary determination according to the present invention. FIG. 5 is an explanatory diagram showing an example when distance information is added to another boundary determination according to the present invention. Description】
100 Mechanical sector type three-dimensional ultrasonic probe 111, 211 Ultrasonic transmission / reception circuit 112, 212 Mechanical sector probe rotation control circuit 113 Swing control circuit 114, 214 Image memory 120, 220 Three-dimensional processing unit 121 Angle detection circuit 122 , 222 High-speed arithmetic processing circuit 115, 215 Image processing circuit 116, 216 Observation monitor 200 Mechanical sector type three-dimensional ultrasonic probe 221 Boundary determination control circuit 217 Observer (user)
218 console

Claims (1)

Ultrasonic elements that transmit and receive ultrasonic waves, and data that obtains tomographic images by rotating the ultrasonic elements and obtains a plurality of tomographic image data that are original data of a three-dimensional image by swinging the ultrasonic elements An acquisition means, a swing signal generating means for generating an encoder signal for swing control, a rotation signal generating means for generating an encoder signal for rotation control, the encoder signal for swing control, and the rotation control encoder signal In an ultrasonic diagnostic apparatus having an angle detection circuit to which an encoder signal is input, the angle resolution obtained from the encoder signal for oscillation control is interpolated using the encoder signal for rotation control for each tomographic image. An ultrasonic diagnostic apparatus for generating an angular resolution of a tomographic image.

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