WO2013085139A1

WO2013085139A1 - System and method for estimating the location and orientation of an ultrasonic probe

Info

Publication number: WO2013085139A1
Application number: PCT/KR2012/007162
Authority: WO
Inventors: 나종범; 이덕운; 남우현
Original assignee: 한국과학기술원
Priority date: 2011-12-07
Filing date: 2012-09-06
Publication date: 2013-06-13
Also published as: KR20130063790A

Abstract

The system and method for estimating the location and orientation of an ultrasonic probe according to the present invention includes: a sensor unit embedded in the ultrasonic probe and sensing movement of the ultrasonic probe to create sensed data; and a location and orientation estimating unit estimating the relative location and orientation of the ultrasonic probe with respect to the location and orientation of the ultrasonic probe at a reference time by using the sensed data. According to the present invention, the location and orientation of the ultrasonic probe can be estimated without additional external devices other than a movement detecting sensor embedded in the ultrasonic probe, and the location and orientation of the ultrasonic probe at a predetermined time can be estimated by using the result of matching an ultrasonic image with another image.

Description

Position and direction estimation system and method of ultrasonic probe

The present invention relates to a system and method for estimating position and direction of an ultrasonic probe.

Ultrasound imaging system is widely used in the field of diagnostic and image-guided interventional procedures because the real-time image can be obtained. In many applications there is a need to estimate the position and orientation of ultrasonic probes.

For example, in order to reconstruct the 2D ultrasound images obtained by scanning the 2D ultrasound probe at various positions and directions, to the 3D ultrasound images, it is necessary to estimate the position and the direction of the probe. In addition, recently, in a system showing a high-resolution computed tomography (CT) or magnetic resonance (MR) image corresponding to an ultrasound image in real time, the position of the ultrasonic probe to acquire the position and direction information where the ultrasound image is obtained in real time. And direction needs to be estimated.

There are two general approaches to estimating the position and direction of an ultrasonic probe. First, there is Electro-Magnetic Tracking. In the electromagnetic tracking method, an electromagnetic field is formed around the ultrasonic probe, and then the position and the direction of the probe are tracked by sensing the magnetic field with a sensor attached to the probe. In the electromagnetic tracking method, when a metal object or the like exists around the probe, an error may occur in the estimation of the position and the direction of the probe due to the interference.

Second, there is optical tracking. In the optical tracking method, a light emitting object such as a light emitting device (LED) is attached to an ultrasonic probe, and then the relative position and direction of the probe is tracked by detecting a movement of the light emitting object through an optical tracking device. However, in the optical tracking method, when the light emitting object attached to the ultrasonic probe is covered by the human body or other objects, the movement cannot be detected, and thus, the position and the direction of the probe cannot be estimated.

There is also an approach that combines the two approaches. However, the conventional tracking method requires an additional device besides a marker such as a sensor or a light emitting object attached to the ultrasonic probe. Accordingly, what is needed is a system and method that can simply estimate the position and orientation of an ultrasonic probe without the need for additional devices.

The present invention has been made to solve the problems of the prior art, and provides a system and method for estimating the position and direction of the ultrasonic probe without additional external device by embedding a sensor that can detect the movement in the ultrasonic probe. Has its purpose.

Technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description of the present invention. .

A position and direction estimation system of an ultrasonic probe according to an embodiment of the present invention includes a sensor unit which is embedded in the ultrasonic probe and detects the movement of the ultrasonic probe to generate sensing data; And a position and direction estimator for estimating a relative position and direction of the ultrasonic probe with respect to the position and direction of the ultrasonic probe at a reference time using the sensing data.

According to an embodiment of the present invention, the position and direction estimation system of the ultrasonic probe further includes an image matching unit for matching the image acquired from the ultrasonic probe with another image at a reference time and outputting the reference position value and the reference direction value of the ultrasonic probe. The position and direction estimator may estimate the position and direction of the ultrasonic probe by using the reference position value and the reference direction value of the ultrasonic probe and the estimated relative position and direction.

Method for estimating the position and direction of the ultrasonic probe according to an embodiment of the present invention comprises the steps of generating the sensing data by detecting the movement of the ultrasonic probe; And estimating a relative position and direction of the ultrasonic probe with respect to the position and direction of the ultrasonic probe at a reference time using the sensing data.

According to an exemplary embodiment of the present invention, a method of estimating the position and direction of an ultrasound probe may include: matching an image acquired from an ultrasound probe with another image at a reference time, and outputting a reference position value and a reference direction value of the ultrasound probe; And estimating the position and direction of the ultrasonic probe by using the reference position value and the reference direction value of the ultrasonic probe and the estimated relative position and direction.

According to the present invention, it is possible to provide a system and method for estimating the position and direction of an ultrasonic probe capable of estimating the position and direction of an ultrasonic probe without additional external devices other than a motion sensor embedded in the ultrasonic probe.

According to the present invention, it is possible to provide a system and method for estimating position and direction of an ultrasonic probe capable of estimating the position and direction of a specific time of an ultrasonic probe by using a result of registration of an ultrasound image with another image.

1 shows a position and direction estimation system of an ultrasonic probe according to an embodiment of the present invention.

2 is a block diagram of a sensor unit according to an embodiment of the present invention.

3 is a flowchart of a method of estimating position and direction of an ultrasonic probe according to an exemplary embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, detailed descriptions of preferred embodiments of the present invention will be described with reference to the accompanying drawings. Note that the shapes and sizes of elements in the drawings may be exaggerated for clarity, and reference numerals and like elements in the drawings may be denoted by the same reference numerals as much as possible even though they are shown in different drawings. Should be. For reference, in the following description of the present invention, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 illustrates a position and direction estimation system 100 of an ultrasonic probe according to an embodiment of the present invention.

As shown in FIG. 1, the position and direction estimation system 100 of the ultrasonic probe according to an exemplary embodiment of the present invention may include a sensor unit 110 and a position and direction estimation unit 120. According to an embodiment, the image matching unit 130 may further include.

The sensor unit 110 is embedded in an ultrasonic probe (not shown) to detect the movement of the ultrasonic probe to generate sensing data. The sensor unit 110 may include one or more sensors embedded in different positions of the ultrasonic probe. 2 is a block diagram of a sensor unit 110 according to an embodiment of the present invention. As shown in FIG. 2, the sensor unit 110 may include at least one of an acceleration sensor 111, an angular velocity sensor 112, and an inclination sensor 113.

The acceleration sensor 111 measures the acceleration by detecting a change in speed of the ultrasonic probe. The angular velocity sensor 112 measures the angular velocity during the rotational movement of the ultrasonic probe in which the angular velocity sensor 1120 is located. The inclination sensor 113 may detect the direction of gravity and measure the inclination direction and the degree of the ultrasonic probe.

The sensor unit 110 according to the embodiment of the present invention may further include other sensors as necessary in addition to the sensors. In addition, a plurality of the acceleration sensor 111, the angular velocity sensor 112, and the tilt sensor 113 may be used. At this time, by embedding the plurality of sensors in different parts of the ultrasonic probe it is possible to estimate the exact position and direction of the ultrasonic probe.

The sensor unit 110 detects the movement of the ultrasonic probe through the

sensors

111, 112, and 113 and generates sensing data.

The sensing data generated from the sensor unit 110 is input to the position and direction estimator 120. The position and direction estimator 120 estimates the relative position and direction ΔT of the ultrasonic probe by using the sensing data. The relative position and direction ΔT of the ultrasonic probe indicates the amount of change in the position and direction of the ultrasonic probe for a predetermined time with respect to the position and direction of the ultrasonic probe at the reference time t _O. Here, the reference time t _O refers to a point in time at which the reference position value and the reference direction value T _O of the ultrasonic probe are calculated. The method of calculating the reference position value and the reference direction value T _O of the ultrasonic probe will be described later.

In this case, the position and direction estimator 120 may estimate the position and direction of the actual ultrasonic probe by using the image matching result of the image matching unit 130. The image matching result of the image matching unit 130 may be a reference position value and a reference direction value T _O indicating the position and direction of the ultrasonic probe at the reference time t _O. Therefore, the position and the direction T of the actual ultrasonic probe are determined by the position and direction estimation unit 120 at the reference position value and the direction value T _O of the ultrasonic probe at the reference time t _O. It can be calculated by summing the relative position and direction [Delta] T vectorically (T = T ₀ + ΔT).

According to an embodiment, the reference position value and the reference direction value T _O of the ultrasonic probe may be set as the origin.

The image matching unit 130 matches the ultrasound image obtained from the ultrasound probe with another image. The other image may include a heterogeneous image different from the ultrasound image, such as a CT image or an MR image. For example, the image matching unit 130 may output the reference position value and the direction value of the ultrasonic probe by using a transformation between the other image and the image acquired from the ultrasonic probe at the reference time t _O. have. The position value and the direction value of a rigid body such as an ultrasonic probe may be defined as a position of a point of an object and a direction vector at that point. On the other hand, the position value and the direction value of the probe can be defined in the same manner with all coordinate values on the probe having a three-dimensional structure. In the present specification, the reference position value and the direction value of the ultrasonic probe are defined in the latter manner and calculated as follows. The transformation relationship indicates which position of the real coordinate system, such as a CT or MR image, the position of all regions of the ultrasound image acquired by the ultrasound probe. In addition, the conversion relationship can be automatically calculated for all the positions on the ultrasonic probe where all the positions correspond to the real coordinate system. Thereby, the reference position value and the reference direction value T _O for which position and in which direction the ultrasonic probe is directed at the reference time t _O can be obtained.

In this case, the reference position value may be obtained by calculating a transformation relationship between the two images using the same reference line, for example, a blood vessel, in the other image and the ultrasound image.

The reference position value and the reference direction value T _O of the ultrasonic probe thus obtained are transferred to the position and direction estimator 120 as described above to estimate the position and the direction T of the ultrasonic probe at a specific time point. Can be used.

The position and direction estimation unit 120 according to an exemplary embodiment of the present invention may use the output value of the image matching unit 130 to correct the error in the sensing data of the sensor unit 110. For example, when an error occurs in the sensing data from the sensor unit 110, an error occurs in the relative position and direction ΔT of the ultrasonic probe estimated by the position and direction estimator 120. Thus, an error occurs in the position and direction T of the ultrasonic probe that is obtained as a result. In order to prevent this, the position and direction of the probe may be initialized by using the result of the image matching unit 130 periodically or when an error occurs in the sensing data. Accordingly, the influence of the sensing data error of the sensor unit 110 can be minimized.

3 is a flowchart of a method for estimating position and direction of an ultrasonic probe according to an exemplary embodiment of the present invention. As shown in FIG. 3, the method of estimating the position and direction of the ultrasonic probe according to an exemplary embodiment of the present invention may include generating sensing data by detecting a movement of the ultrasonic probe (S10) and using the sensing data as a reference time t It may include a step (S20) of estimating the relative position and direction (ΔT) of the ultrasonic probe relative to the position and direction of the ultrasonic probe of _O ). According to an embodiment of the present invention, matching the image obtained from the ultrasonic probe with another image at a reference time t _O and outputting the reference position value and the reference direction value T _O of the ultrasonic probe (S30) and the ultrasonic wave. The method may further include estimating (S40) the position and the direction T of the ultrasound probe by using the reference position value and the reference direction value T _O of the probe and the estimated relative position and direction ΔT. In this case, steps S30 and S40 may be performed periodically or repeatedly when an error occurs in the sensing data. Accordingly, by initializing the reference position value and the direction value of the ultrasonic probe, it is possible to minimize the effect of generating the sensing data error.

The position and direction T of the ultrasonic probe thus obtained are set again as the reference position and direction, and the positions and directions of the ultrasonic probe after a specific time elapse can be estimated by repeating steps S10 to S40 shown in FIG. have. Accordingly, it is possible to track the position and direction of the ultrasonic probe in real time.

Step S30 illustrated in FIG. 3 may include the steps described below according to an embodiment. That is, the step (S30) of outputting the reference position value and the reference direction value T _O of the ultrasonic probe may include extracting the reference blood vessel from another image; Extracting the same vessel as the reference vessel from the ultrasound image acquired from the ultrasound probe at a reference time t _O ; And calculating a transformation relationship between the two images using the same reference vessel extracted from the image obtained from the ultrasound probe at the other image and the reference time t _O. Here, the reference position value and the direction value of the ultrasonic probe may be output at the reference time t _O according to the conversion relationship.

In other words, blood vessels that may be a reference may be extracted in advance from the acquired CT or MR images. In addition, the same blood vessel may be automatically extracted from the ultrasound image obtained from the ultrasound probe at the reference time t _O. Subsequently, a transformation relationship between the two images may be calculated using the reference vessel extracted from the ultrasound image and the reference vessel extracted from the CT or MR image as a center line.

As described above, by using the position and direction estimation system and method of the ultrasonic probe according to an embodiment of the present invention, the position and direction of the ultrasonic probe in real time without additional external devices other than the motion sensor built into the ultrasonic probe in real time can do.

In addition, by using the ultrasound probe position and direction estimation system and method according to an embodiment of the present invention, it is possible to track the position and direction of the ultrasound probe at any time using the matching result of the ultrasound image and other images. .

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. will be. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the detailed description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

The present invention can be usefully used in various image-based medical diagnosis, medical intervention, surgery, etc., which require estimation of the position and direction of a real-time ultrasound probe.

Claims

A sensor unit embedded in an ultrasonic probe and configured to sense movement of the ultrasonic probe to generate sensing data; And

And a position and direction estimator configured to estimate a relative position and direction of the ultrasonic probe with respect to the position and direction of the ultrasonic probe at a reference time using the sensing data.

Position and orientation estimation system for ultrasonic probes.
The method according to claim 1,

The image matching unit outputs a reference position value and a reference direction value of the ultrasound probe by matching the image acquired from the ultrasound probe with another image at the reference time.

And the position and direction estimator estimates the position and direction of the ultrasonic probe by using the reference position value and the reference direction value of the ultrasonic probe and the estimated relative position and direction.
The method according to claim 2,

The image junction unit,

And a reference position value and a direction value of the ultrasonic probe according to a conversion relationship between the other image and the image acquired from the ultrasonic probe at the reference time.
The method according to any one of claims 1 to 3,

The sensor unit is a position and direction estimation system of the ultrasonic probe including at least one of an acceleration sensor, an angular velocity sensor and a tilt sensor.
The method according to claim 2 or 3,

The other image is a CT image or MR image position and direction estimation system of the ultrasonic probe.
The method according to claim 2 or 3,

And a position and direction estimation system of the ultrasonic probe which receives the output value of the image matching unit periodically.
Generating sensing data by detecting a movement of the ultrasonic probe; And

Estimating a relative position and direction of the ultrasonic probe with respect to the position and direction of the ultrasonic probe at a reference time using the sensing data.

Method for estimating the position and direction of an ultrasonic probe.
The method according to claim 7,

Matching the image acquired from the ultrasound probe with another image at the reference time and outputting a reference position value and a reference direction value of the ultrasound probe; And

Estimating the position and direction of the ultrasonic probe by using the reference position value and the reference direction value of the ultrasonic probe and the estimated relative position and direction;

Method for estimating the position and direction of an ultrasonic probe.
The method according to claim 8,

The step of outputting the reference position value and the direction value of the ultrasonic probe,

Extracting a reference blood vessel from the other image;

Extracting the reference blood vessel from an image acquired from the ultrasound probe at the reference time; And

Calculating a transformation relationship between the other image and the image obtained from the ultrasound probe by using the same reference vessel extracted from the other image and the image obtained from the ultrasound probe at the reference time.

Method for estimating the position and direction of an ultrasonic probe.
The method according to claim 8 or 9,

The other image is a CT image or MR image position and direction estimation method of the ultrasound probe.
The method according to claim 8,

Matching the image acquired from the ultrasound probe with another image at the reference time and outputting a reference position value and a reference direction value of the ultrasound probe; And

And estimating the position and direction of the ultrasonic probe by using the reference position value and the reference direction value of the ultrasonic probe and the estimated relative position and direction are periodically performed.