CN109464163A - Fetal head direction measuring device, measuring method and measuring device simulator - Google Patents

Abstract

Translated fromChinese

本发明属于产科监护领域，涉及一种胎头方向测量装置、测算方法及测量装置模拟器。胎头方向测量装置包括数据处理单元以及分别与数据处理单元相连的胎头特征点定位单元、参考平面和参考向量定位单元。通过获取胎头两个特征点之间的方向向量，然后计算方向向量在参考平面上的第一投影向量，计算参考向量在参考平面上的第二投影向量，最后计算第一投影向量至第二投影向量的角度，确定胎头方向。本发明提供胎头方向测量装置和方法，可以更加方便、灵活的测算胎头方位，用户操作简单灵活；提供的胎头方向测量装置模拟器，可以模拟胎头方向测量原理，对胎头方向测量精确度进行检验，提高算法可靠性。

The invention belongs to the field of obstetric monitoring, and relates to a fetal head direction measuring device, a measuring method and a measuring device simulator. The fetal head direction measuring device includes a data processing unit, a fetal head feature point positioning unit, a reference plane and a reference vector positioning unit respectively connected with the data processing unit. By obtaining the direction vector between the two feature points of the fetal head, then calculating the first projection vector of the direction vector on the reference plane, calculating the second projection vector of the reference vector on the reference plane, and finally calculating the first projection vector to the second projection vector The angle of the projected vector to determine the direction of the fetal head. The invention provides a fetal head direction measuring device and method, which can measure the fetal head direction more conveniently and flexibly, and the user's operation is simple and flexible; the provided fetal head direction measuring device simulator can simulate the fetal head direction measurement principle, and measure the fetal head direction. The accuracy is checked to improve the reliability of the algorithm.

Description

Fetal head direction measuring device, measuring method and measuring device simulator

Technical field

The invention belongs to obstetrics' monitoring arts, it is related to a kind of fetal head direction measuring device, measuring method and measuring device mouldQuasi- device.

Background technique

In childbirth is learned, fetal head and pelvis dynamic space relationship (referred to as " head basin relationship ") are selected and are disposed to childbirth optionsIt is most important；Clinical obstetrics needs accurately monitor these data at any time, to help doctor and midwife to carry out the childbirth of scienceDecision.

On childbirth is learned, fetal head direction is one of the important parameter of spatial relationship indicated between fetal head and pelvis.Fetal headDirection describes the relationship of fetus presentation occipital bone Yu maternal pelvic front, rear, left and right, can be divided into eight orientation: before pillow, left pillowBefore, after left occipitotransverse (LOT), left occipitoposterior (LOP), pillow, right occipitoposterior (ROP), right occipitotransverse, right occipitoanterior.If abnormal fetal position is not corrected, when childbirth, can cause difficultyIt produces.

A kind of fetal head bearing measuring method based on electromagnetic location and ultrasonic imaging is (referring to the middle promulgated by the State Council of South China Science & Engineering UniversityA kind of bright patent " fetal head bearing measuring method based on electromagnetic location and ultrasonic imaging ", publication date is on July 21st, 2017, publicThe number of opening is CN106963378A), lower edge coordinate and fifth lumbar vertebra on pregnant woman's pubic symphysis are measured by electromagnetic positioning system firstSpinous process coordinate；Then the normal vector of sagittal plane is calculated；Integrated probe transversal scanning pregnant woman abdominal cavity is used again, obtains cephalotomyThe ultrasound image of characteristic point, and thereby determine that measurement pattern；Calculate the direction vector under each measurement pattern；Calculate all directions vectorWith the angle of sagittal plane normal vector；Fetal head orientation is finally determined by angle situation.This method utilizes ultrasound and Magnetic oriented systemFetal head characteristic point is positioned, calculates the angle of all directions vector and sagittal plane normal vector to measure fetal head orientation, this method can be withIt requires no vagina and refers to that inspection can be convenient for measuring fetal head orientation.But the above method is only applicable to sagittal plane and pregnant woman abdominal cavity is scannedThe vertical situation of plane, user's operation is more complicated, and popularization is subject to certain restrictions.

Summary of the invention

To solve the above problems, the present invention provides a kind of fetal head direction measuring device, including data processing unit and pointFetal head positioning feature point unit, reference planes and the reference vector positioning unit not being connected with data processing unit.By to tireHead positioning feature point, the positioning of the reference planes and reference vector of pelvis, the projection for carrying out direction vector and reference vector calculate,Determine fetal head direction.This method can be more convenient, is more flexible, more effectively determining fetal head direction.

The present invention also provides a kind of fetal head direction measuring methods and a kind of fetal head direction measuring device simulator.

Measuring device of the invention adopts the following technical scheme that a kind of fetal head direction measuring device, including data processing listMember and fetal head positioning feature point unit, reference planes and the reference vector positioning unit being connected respectively with data processing unit,Wherein:

Fetal head positioning feature point unit, for positioning the spatial position of the two or more characteristic points of fetal head；

Reference planes and reference vector positioning unit, for positioning the reference planes and reference vector of pelvis；

Data processing unit, the first direction vector between acquisition two characteristic points of fetal head, then calculate direction vector and existThe first projection vector in reference planes calculates the second projection vector of reference vector on the reference plane, finally calculates firstProjection vector determines fetal head direction to the angle of the second projection vector.

Further, fetal head positioning feature point unit includes the ultrasonic probe with the first alignment sensor.

Further, reference planes and reference vector positioning unit include the second alignment sensor.

Fetal head direction measuring method of the invention adopts the following technical scheme that, a kind of fetal head direction measuring method, including withLower step:

Obtain the direction vector of fetal head fisrt feature point to fetal head second feature point；

Position the reference planes and reference vector of pelvis；

Calculate fetal head fisrt feature point to fetal head second feature point direction vector on the reference plane first project toAmount；

Calculate the second projection vector of reference vector on the reference plane；

The angle for calculating the first projection vector to the second projection vector determines fetal head direction.

Further, obtain fetal head fisrt feature point to fetal head second feature point direction vector the step of include:

With ultrasonic probe scanning fetal head fisrt feature point and fetal head second feature point with the first alignment sensor；

According to the posture information that the first alignment sensor records, fetal head fisrt feature point, fetal head second feature point are calculatedThree-dimensional coordinate, and then calculate the direction vector of fetal head fisrt feature point to fetal head second feature point.

Further, the method for positioning the reference planes of pelvis is any one in following three kinds of methods:

1. positioning the three-dimensional coordinate of the upper margin of pubic bone of pelvis, lower margin of pubic bone, reference planes are to join by pubisClose edge and perpendicular to the plane of upper margin of pubic bone and lower margin of pubic bone line；

2. positioning the three-dimensional coordinate of the upper margin of pubic bone of pelvis, left anterior superior spine, right anterior superior spine, reference planes are warpCross upper margin of pubic bone, left anterior superior spine, 3 points of right anterior superior spine of plane；

3. positioning the three-dimensional coordinate of the upper margin of pubic bone of pelvis, lower margin of pubic bone, the 5th spinous process of lumbar vertebra, reference planesFor by upper margin of pubic bone, the 5th spinous process of lumbar vertebra and perpendicular to upper margin of pubic bone, lower margin of pubic bone, the 5th spinous process of lumbar vertebra threePlane where point.

Further, the method for positioning the reference vector of pelvis is any one in following two method:

1. positioning the three-dimensional coordinate of the left anterior superior spine of pelvis, right anterior superior spine, reference vector is left anterior superior spine to the right sideThe vector of anterior superior spine；

2. positioning the three-dimensional coordinate of the upper margin of pubic bone of pelvis, the 5th spinous process of lumbar vertebra, reference vector is upper margin of pubic boneTo the vector of the 5th spinous process of lumbar vertebra.

The simulator of fetal head direction measuring device of the present invention adopts the following technical scheme that a kind of fetal head direction measuring device is touchedQuasi- device includes the cuboid container of upper opening, and several artificial lines for being parallel to container bottoms, simulation are equipped in cuboid containerLine both ends are individually fixed in the side opposite of cuboid container, rounded to be uniformly distributed.The side opposite analog references of cuboid containerPlane, simulator vertical direction analog references vector, artificial line simulate fetal head characteristic point in the mark that ultrasound image is presented.

The water of artificial line was covered in injection in cuboid container；Ultrasonic probe is suspended in above cuboid container entrance, and ultrasound is visitedHead surface is immersed in the water；Using water as artificial line in medium scanning water, the mark point of circular distribution is shown in ultrasound image；SuperThe round two o'clock being diametrically opposed to one another arbitrarily is marked in acoustic image, is calculated its direction vector, is simulated the direction of two fetal head characteristic pointsVector calculates the first projection vector of direction vector on the reference plane, calculates the second throwing of reference vector on the reference planeShadow vector finally calculates the angle of the first projection vector to the second projection vector, determines fetal head direction.

The present invention have the following advantages compared with the existing technology and the utility model has the advantages that

1, the present invention provides fetal head direction measuring device, measuring and calculating fetal head orientation that can be more convenient and flexible, user's operationIt is simpler flexible.

2. the result in the fetal head orientation that fetal head direction provided by the invention measuring method calculates is more accurate.

3, fetal head direction measuring device simulator provided by the invention can simulate fetal head orientation measurement principle, to fetal headOrientation measurement accuracy is tested, and algorithm reliability is improved.

Detailed description of the invention

Fig. 1 is fetal head direction measuring device module map；

Fig. 2 is one schematic diagram of method for positioning pelvis reference planes；

Fig. 3 is two schematic diagram of method for positioning pelvis reference planes；

Fig. 4 is three schematic diagram of method for positioning pelvis reference planes；

Fig. 5 is one schematic diagram of method for positioning pelvis reference vector；

Fig. 6 is two schematic diagram of method for positioning pelvis reference vector；

Fig. 7 is one of fetal head direction measuring device simulator schematic diagram；

Fig. 8 is the two of fetal head direction measuring device simulator schematic diagram.

Specific embodiment

Present invention will now be described in further detail with reference to the embodiments and the accompanying drawings, but embodiments of the present invention are unlimitedIn this.

Embodiment

A kind of fetal head direction measuring device, as shown in Figure 1, include data processing unit and respectively with data processing unitConnected fetal head positioning feature point unit, reference planes and reference vector positioning unit, in which:

Fetal head positioning feature point unit, for positioning the spatial position of the two or more characteristic points of fetal head, including with theThe ultrasonic probe of one alignment sensor；

Reference planes and reference vector positioning unit, for positioning the reference planes and reference vector of pelvis, including secondAlignment sensor；

Data processing unit, the first direction vector between acquisition two characteristic points of fetal head, then calculate direction vector and existThe first projection vector in reference planes calculates the second projection vector of reference vector on the reference plane, finally calculates firstProjection vector determines fetal head direction to the angle of the second projection vector.

It should be noted that positioning the two or more characteristic points of fetal head using the ultrasonic probe with the first alignment sensorSpatial position, i.e. Freehand three-dimensional ultrasound is the research heat in ultrasound image three-dimensional reconstruction field in recent yearsOne of point, this technology have tended to be mature, and concrete methods of realizing can refer to correlative theses, and which is not described herein again.

A kind of fetal head direction measuring method, comprising the following steps:

A, the direction vector of fetal head fisrt feature point to fetal head second feature point is obtained；

B, the reference planes and reference vector of pelvis are positioned；

C, calculate fetal head fisrt feature point to fetal head second feature point direction vector on the reference plane first projectVector；

D, the second projection vector of reference vector on the reference plane is calculated；

E, the angle for calculating the first projection vector to the second projection vector, determines fetal head direction.

It should be noted that the vector, coordinate in above-mentioned measuring method in each step are all based on same three-dimensional space(being called " known three-dimensional space " in the present invention).

Present invention determine that the principle in fetal head orientation is: first by obtaining fetal head fisrt feature point to fetal head second feature pointDirection vector come determine characterization fetal head direction direction vector, then position pelvis reference planes and reference vector, i.e., it is fixedThe direction and fetal head orientation zero-bit of position pelvis.By the direction vector of fetal head fisrt feature point to fetal head second feature point, pelvisReference vector is projected to the same reference planes, then the angle of calculating direction vector to reference vector.In the present embodiment,The angular range for calculating direction vector to reference vector is 0~360 degree, one corresponding every 45 degree of angles since initial angle θFetal head direction: before pillow, after left occipitoanterior (LOA), left occipitotransverse (LOT), left occipitoposterior (LOP), pillow, right occipitoposterior (ROP), right occipitotransverse, right occipitoanterior, angle, fetal head direction pairIt should be related to as shown in the table:

Angle degree	Fetal head direction	Angle degree	Fetal head direction
				(θ~θ+45) %360	Before pillow	(θ+181~θ+225) %360	After pillow
(θ+46~θ+90) %360	Left occipitoanterior (LOA)	(θ+226~θ+270) %360	Right occipitoposterior (ROP)
				(θ+91~θ+135) %360	Left occipitotransverse (LOT)	(θ+271~θ+325) %360	Right occipitotransverse
(θ+136~θ+180) %360	Left occipitoposterior (LOP)	(θ+326~θ+360) %360	Right occipitoanterior

It should be noted that the angular range between vector in public's meaning is [0,180], calculation method is with twoThe dot product of vector is divided by two vector field homoemorphisms, and then anticosine obtains.And in the present embodiment, direction vector " arrives " reference vectorAngle need to indicate the positional relationship between two vectors with 0~360 degree, need exist for the multiplication cross for using two vectors,Characterization direction vector " arrives " directionality of the angle of reference vector, with the folder being different between direction vector "AND" reference vectorRange is extended to [0,360] by angle.This is the common sense of plane vector geometric operation, therefore repeats no more herein.% is indicated in tableComplementation.

The present invention projects direction vector, reference vector to the reason in the same reference planes: due to giving a birthCheng Zhong, fetal head decline along birth canal, and birth canal is not straight line, it is therefore desirable to by characterize fetal head direction direction vector andIt indicates that the reference vector of pelvis characteristic point projects to the same reference planes, could will be pressed from both sides under unified correspondence standard in this wayAngle number corresponds to corresponding fetal head direction.Publication date relative to South China Science & Engineering University is on July 21st, 2017, Publication No.A kind of Chinese invention patent " fetal head bearing measuring method based on electromagnetic location and ultrasonic imaging " of CN106963378A providesMethod, the fetal head direction measuring method of the present embodiment, will indicate fetal head characteristic point direction vector and indicate pelvis featureThe reference vector of point projects to the same reference planes, then calculates angle between the two, the tire that the present invention calculates againThe result in head orientation is more accurate.

Further, the step of direction vector of the fetal head fisrt feature point to fetal head second feature point is obtained in step A is wrappedIt includes:

A1, fetal head fisrt feature point and fetal head second feature point are scanned with the ultrasonic probe with the first alignment sensor；

A2, its posture information in known three-dimensional space recorded according to the first alignment sensor, calculate fetal head firstThe three-dimensional coordinate of characteristic point, fetal head second feature point in known three-dimensional space, and then fetal head fisrt feature point is calculated to fetal headThe direction vector of second feature point.

The present embodiment fetal head fisrt feature point and fetal head second feature point refer to the fetal head solution that can be shown in ultrasound imageStructure is cutd open, such as: occipitalia, forehead, bridge of the nose bone, neck bone, eye socket etc. select two of them that can characterize the feature in fetal head directionPoint, line direction represent direction of the fetal head in birth canal.Specific practice is: using the ultrasound for having the first alignment sensorThese characteristic points of scanning probe calculate these spies according to the posture information in known three-dimensional space that alignment sensor recordsThe three-dimensional coordinate for levying point, then calculates the direction vector of preset two fetal head characteristic points.It should be noted that different fetal heads are specialThe direction vector for levying point, represents the different direction of fetal head, i.e. direction vector is different from the initial value θ of reference vector, with specific reference toDepending on direction vector and the angle of reference vector and actual fetal head orientation title.For example, when direction vector and reference vectorWhen angle initial value θ=30 degree, fetal head direction initial bit before pillow, then before 30~75 degree of angle is pillows, and so on.

Further, the method that the reference planes of pelvis are positioned in step B is any one in following three kinds of methods:

1. positioning the three-dimensional coordinate of the upper margin of pubic bone, lower margin of pubic bone of pelvis in known three-dimensional space, referencePlane is by upper margin of pubic bone and perpendicular to the plane of upper margin of pubic bone and lower margin of pubic bone line；

2. positioning the three-dimensional of the upper margin of pubic bone, left anterior superior spine, right anterior superior spine of pelvis in known three-dimensional spaceCoordinate, reference planes are by upper margin of pubic bone, left anterior superior spine, 3 points of right anterior superior spine of plane；

3. positioning three of the upper margin of pubic bone, lower margin of pubic bone, the 5th spinous process of lumbar vertebra of pelvis in known three-dimensional spaceCoordinate is tieed up, reference planes are by upper margin of pubic bone, the 5th spinous process of lumbar vertebra and perpendicular under upper margin of pubic bone, pubic symphysisPlane where edge, 3 points of the 5th spinous process of lumbar vertebra.

The method of the reference planes of three kinds of positioning pelvis provided in this embodiment are as follows:

Method one: as shown in Fig. 2, upper margin of pubic bone S1, the lower margin of pubic bone S2 of positioning pelvis are in known three-dimensional spaceBetween in three-dimensional coordinate, reference planes α be by upper margin of pubic bone S1 and perpendicular to upper margin of pubic bone S1 and pubic symphysisThe plane of lower edge S2 line.

Method two: as shown in figure 3, upper margin of pubic bone S1, left anterior superior spine T1, the right anterior superior spine T2 of positioning pelvis existThree-dimensional coordinate in known three-dimensional space, reference planes β are by before upper margin of pubic bone S1, left anterior superior spine T1, right iliumThe plane that 3 points of spine T2；

Method three: as shown in figure 4, upper margin of pubic bone S1, lower margin of pubic bone S2, the 5th spinous process of lumbar vertebra of positioning pelvisThree-dimensional coordinate of the L5 in known three-dimensional space, reference planes δ are by upper margin of pubic bone S1, the 5th spinous process of lumbar vertebra L5 and to hang downDirectly in the plane where upper margin of pubic bone, lower margin of pubic bone, 3 points of the 5th spinous process of lumbar vertebra.Reference planes δ is to pass through pubisThe plane of joint upper limb S1, lower margin of pubic bone S2,3 points of the 5th spinous process of lumbar vertebra L5.

In the present embodiment, the upper margin of pubic bone S1, lower margin of pubic bone S2, the 5th spinous process of lumbar vertebra L5, left ilium of pelvis are positionedAlignment sensor can be used to directly acquire for the three-dimensional coordinate of Ant sup T1, right anterior superior spine T2 in known three-dimensional space, can alsoTo use the ultrasonic probe for having alignment sensor to calculate in ultrasound image by label.

Further, the method that the reference vector of pelvis is positioned in step B is any one in following two method:

1. positioning the three-dimensional coordinate of the left anterior superior spine, right anterior superior spine of pelvis in known three-dimensional space, reference vectorFor left anterior superior spine to the vector of right anterior superior spine；

2. position the three-dimensional coordinate in known three-dimensional space of upper margin of pubic bone, the 5th spinous process of lumbar vertebra of pelvis, with reference toAmount is vector of the upper margin of pubic bone to the 5th spinous process of lumbar vertebra.

The method of the reference planes of two kinds of positioning pelvis provided in this embodiment are as follows:

Method one: as shown in figure 5, left anterior superior spine T1, the right anterior superior spine T2 of positioning pelvis are in known three-dimensional spaceThree-dimensional coordinate, reference vector be left anterior superior spine T1 to right anterior superior spine T2 vector.

Method two: as shown in fig. 6, upper margin of pubic bone S1, the 5th spinous process of lumbar vertebra L5 of positioning pelvis are in known three-dimensional spaceIn three-dimensional coordinate, reference vector be upper margin of pubic bone S1 to the 5th spinous process of lumbar vertebra L5 vector.

In the present embodiment, before positioning the upper margin of pubic bone S1 of pelvis, the 5th spinous process of lumbar vertebra L5, left anterior superior spine T1, right iliumAlignment sensor can be used to directly acquire for three-dimensional coordinate of the upper spine T2 in known three-dimensional space, and also can be used and passes with positioningThe ultrasonic probe of sensor is calculated in ultrasound image by label.

The present invention also provides a kind of simulator for analog detection fetal head direction measuring device, the length including upper openingCube container, cuboid container is interior to be equipped with several artificial lines for being parallel to container bottoms, and artificial line both ends are individually fixed in rectangularThe side opposite of body container, it is rounded to be uniformly distributed.The side opposite analog references plane of cuboid container, simulator vertical direction mouldQuasi- reference vector, artificial line simulate fetal head characteristic point in the mark that ultrasound image is presented.

As shown in Fig. 7~8, the simulator provided in this embodiment for analog detection fetal head direction measuring device is topThe cuboid container of opening, cuboid container is interior to be equipped with several artificial line L for being parallel to container bottoms, the both ends artificial line L differenceIt is fixed on the side opposite U of cuboid container, it is rounded to be uniformly distributed；The side opposite U analog references plane of cuboid container, simulationDevice vertical direction T analog references vector, artificial line L simulate fetal head characteristic point in the mark that ultrasound image is presented.In use, by sufficientIt measures in water injection cuboid container, water must cover artificial line；It holds ultrasonic probe to be suspended in above cuboid container entrance, ultrasound is visitedHead surface must be immersed in the water.Using water as medium, artificial line L in water is scanned, shows the mark of circular distribution in ultrasound image at this timeNote point.The round two o'clock being diametrically opposed to one another arbitrarily is marked in ultrasound image, is calculated its direction vector, is simulated two fetal head featuresThe direction vector of point, with the side opposite U analog references plane of cuboid container, simulator vertical direction T analog references vector.MeterThe first projection vector of direction vector on the reference plane is calculated, the second projection vector of reference vector on the reference plane is calculated,The angle for finally calculating the first projection vector to the second projection vector determines fetal head direction.

The above embodiment is a preferred embodiment of the present invention, but embodiments of the present invention are not by above-described embodimentLimitation, other any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present invention,It should be equivalent substitute mode, be included within the scope of the present invention.

Claims (10)

1. a kind of fetal head direction measuring device, which is characterized in that the fetal head direction measuring device includes data processing unit, withAnd fetal head positioning feature point unit, reference planes and the reference vector positioning unit being connected respectively with data processing unit, in which:

Fetal head positioning feature point unit, for positioning the spatial position of the two or more characteristic points of fetal head；

Reference planes and reference vector positioning unit, for positioning the reference planes and reference vector of pelvis；

Data processing unit, the first direction vector between acquisition two characteristic points of fetal head, then calculate direction vector and are referring toThe first projection vector in plane, calculates the second projection vector of reference vector on the reference plane, finally calculates the first projectionVector determines fetal head direction to the angle of the second projection vector.

2. fetal head direction measuring device according to claim 1, which is characterized in that the fetal head positioning feature point unit packetInclude the ultrasonic probe with the first alignment sensor.

3. fetal head direction measuring device according to claim 1 or 2, which is characterized in that the reference planes and with reference toMeasuring positioning unit includes the second alignment sensor.

4. a kind of fetal head direction measuring method, which comprises the following steps:

Obtain the direction vector of fetal head fisrt feature point to fetal head second feature point；

Position the reference planes and reference vector of pelvis；

Calculate fetal head fisrt feature point to fetal head second feature point direction vector the first projection vector on the reference plane；

Calculate the second projection vector of reference vector on the reference plane；

The angle for calculating the first projection vector to the second projection vector determines fetal head direction.

5. fetal head direction according to claim 4 measuring method, which is characterized in that obtain fetal head fisrt feature point to fetal headThe step of direction vector of second feature point includes:

With ultrasonic probe scanning fetal head fisrt feature point and fetal head second feature point with the first alignment sensor；

According to the posture information that the first alignment sensor records, the three-dimensional of fetal head fisrt feature point, fetal head second feature point is calculatedCoordinate, and then calculate the direction vector of fetal head fisrt feature point to fetal head second feature point.

6. fetal head direction according to claim 4 measuring method, which is characterized in that the method for positioning the reference planes of pelvisFor any one in following three kinds of methods:

1. positioning the three-dimensional coordinate of the upper margin of pubic bone of pelvis, lower margin of pubic bone, reference planes are by pubic symphysisEdge and perpendicular to the plane of upper margin of pubic bone and lower margin of pubic bone line；

2. positioning the three-dimensional coordinate of the upper margin of pubic bone of pelvis, left anterior superior spine, right anterior superior spine, reference planes are by shameSynostosis upper limb, left anterior superior spine, 3 points of right anterior superior spine of plane；

3. positioning the three-dimensional coordinate of the upper margin of pubic bone of pelvis, lower margin of pubic bone, the 5th spinous process of lumbar vertebra, reference planes are warpCross upper margin of pubic bone, the 5th spinous process of lumbar vertebra and perpendicular to upper margin of pubic bone, lower margin of pubic bone, three point institute of the 5th spinous process of lumbar vertebraPlane.

7. fetal head direction according to claim 4 measuring method, which is characterized in that the method for positioning the reference vector of pelvisFor any one in following two method:

1. positioning the three-dimensional coordinate of the left anterior superior spine of pelvis, right anterior superior spine, reference vector is before left anterior superior spine to right iliumThe vector of upper spine；

2. positioning the three-dimensional coordinate of the upper margin of pubic bone of pelvis, the 5th spinous process of lumbar vertebra, reference vector is upper margin of pubic bone to theThe vector of 5 spinous process of lumbar vertebra.

8. the fetal head direction measuring method according to any one of claim 4-7, which is characterized in that direction vector to referenceThe angular range of vector is 0~360 degree, since initial angle θ, every the corresponding fetal head direction in 45 degree of angles.

9. a kind of simulator of fetal head direction measuring device characterized by comprising the cuboid container of upper opening, it is rectangularSeveral artificial lines for being parallel to container bottoms are equipped in body container, artificial line both ends are individually fixed in the side pair of cuboid containerFace, it is rounded to be uniformly distributed；The side opposite analog references plane of cuboid container, vertical direction analog references vector, artificial lineFetal head characteristic point is simulated in the mark that ultrasound image is presented.

10. simulator according to claim 9, which is characterized in that artificial line was covered in injection in the cuboid containerWater；Ultrasonic probe is suspended in above cuboid container entrance, and ultrasonic probe surface is immersed in the water；Using water to be simulated in medium scanning waterLine shows the mark point of circular distribution in ultrasound image；The round two o'clock being diametrically opposed to one another arbitrarily is marked in ultrasound image,Its direction vector is calculated, the direction vector of two fetal head characteristic points is simulated, calculates the first throwing of direction vector on the reference planeShadow vector calculates the second projection vector of reference vector on the reference plane, finally calculates the first projection vector to the second projectionThe angle of vector determines fetal head direction.