CN102846337B - The localization method of 3 D ultrasound system and impact point thereof and device - Google Patents

Abstract

The invention discloses localization method and the device of a kind of 3 D ultrasound system and impact point thereof, sound field thickness factor is taken into account, from different directions Multiple-Scan impact point, obtain the coordinate of impact point in ultrasonic scanning space; According to the projection of the correlated measure of all directions, for each scanning assigns weight; Impact point is calculated at the coordinate with reference to space to the transformation matrix in this reference space according to weight and each ultrasonic scanning space coordinates; Utilize obtain in advance from ultrasonic scanning space to the transformation matrix in world coordinates space by impact point with reference to the coordinate transform in space to world coordinates space.The axis that the present invention's ultrasonic space precision is higher and lateral error make up the low thickness error of precision, thus improve the positioning precision of impact point in ultrasonic scanning space.

Description

The localization method of 3 D ultrasound system and impact point thereof and device

Technical field

The present invention relates to a kind of 3 D ultrasound system, particularly relate to localization method and the device of the impact point of 3 D ultrasound system.

Background technology

3 D ultrasound system gets more and more in fusion of imaging, surgical navigational, biopsy and the application of the field such as to melt, and it is more directly perceived than two-dimensional ultrasonic image, and comprises more time and space shape information.3 D ultrasound system based on free arm (freehand) is more more flexible than mechanical 3 D ultrasound system, has arbitrarily angled scanning, the advantages such as mobile space is unrestricted.Conventional freedom-arm, three-D ultrasonic system has: based on the freedom-arm, three-D ultrasonic system of electromagnetic transducer; Based on the freedom-arm, three-D ultrasonic system of active light/passive optical sensor.Three-dimensional scaling is a link important in freedom-arm, three-D ultrasonic system, refers to by someway or device, determines the transformation relation between each space coordinates in 3 D ultrasound system.Know the transformation relation between each space coordinates, with ultrasonic scanning localizing objects point, the coordinate of ground point of plane of ultrasound is through coordinate transform, from ultrasonic scanning spatial alternation to position sensor space, transform to world space again, thus know the position of impact point at world space, for ultrasonic fusion of imaging, surgical navigational etc. provide positional information.A step important in ultrasonic fusion of imaging is the some one_to_one corresponding registration by the point on ultrasonoscopy and another modal data, its essence is and the position of impact point in world coordinates is mapped with the position of impact point in another modal data, accurately obtain the position of impact point in world coordinates and raising registration accuracy is had a significant impact.

The acoustic beam relevant to 3 D ultrasound system has error in three directions: axial error, lateral error, thickness error.

Axial error (axial): the error on ultrasonic beam axis, relevant with wavelength in theory, only have when 2 distances are greater than 1/2 of wavelength, ultrasonicly could produce two echoes respectively, equal minimum range ultrasonic beam axis being differentiated point-to-point transmission.

Lateral error (lateral): also known as lateral error, the error vertical with axial direction, it and focal position, axial depth, aperture, ultrasonic beam diameter, multi-beam synthesis is relevant.Horizontal direction direction perpendicular to axial direction, coexists in ultrasound scan planes with axial.

Thickness error (elevational, thickness): the error on plane of ultrasound thickness direction, it with probe crystal oscillator, the geometry of acoustic lens, axial depth is relevant.Thickness direction and axial direction, lateral is mutually vertical.

Current technology have ignored the thickness of ultrasonic sound field, regards ultrasonic scanning space as X to the conversion of position sensor space _uszthe 2D plane of=0 to the conversion of 3d space, X here _uszthe coordinate of the ultrasonic imaging space thickness direction (can Z axis be expressed as) referred to.

But in actual applications, because ultrasonic beam itself has certain thickness, the feature of ultrasonic beam far field diversity makes ultra sonic imaging not be the situation in the unlimited thin cross section of reflection one but have certain thickness and the plane of dispersing gradually simultaneously, on stricti jurise, cause the inaccurate of location because ignoring the thickness of ultrasonic sound field, and then affect the precision of ultrasonic fusion of imaging and surgical navigational.

During ultrasonic scanning, because the physical characteristic of probe determines that the error of ultrasonic all directions is not identical.Axially and lateral error less, thickness direction error is larger.In two dimensional ultrasound systems, what mainly pay close attention to is axis and lateral error, more to the optimization of axis and lateral error, pays close attention to less to thickness direction error, optimizes also less or not optimization.Mostly do not consider sound field thickness factor in current freedom-arm, three-D ultrasonic system, but in 3 D ultrasound system thickness error impact than axially and lateral error much larger.Although some technology considers sound field thickness factor, it reduces by special device the impact that thickness error brings, and uses very inconvenient.

Summary of the invention

The main technical problem to be solved in the present invention is, provides localization method and the device of a kind of 3 D ultrasound system and impact point thereof, sound field thickness factor is taken into account, demarcates impact point, improves the positioning precision of impact point.

According to an aspect of the present invention, a kind of object location method of 3 D ultrasound system is provided, comprises:

Obtain the coordinate of this impact point in each ultrasonic scanning space when ultrasonic probe repeatedly scans same impact point from different directions;

Select a ultrasonic scanning space as with reference to space, by all ultrasonic scanning space coordinatess of obtaining after Multiple-Scan to this reference space projection, obtain the transformation matrix of each ultrasonic scanning space coordinates to this reference space;

Be that each scan-data assigns weight according to the correlated measure of all directions;

Impact point is calculated at the coordinate with reference to space to the transformation matrix in this reference space according to weight and each ultrasonic scanning space coordinates;

Utilize obtain in advance from ultrasonic scanning space to the transformation matrix in world coordinates space by impact point with reference to the coordinate transform in space to world coordinates space.In one embodiment, the described correlated measure according to all directions be each time scan-data when assigning weight according to following rule: the component of weight on axial direction, lateral or thickness direction, determine according to the projected size that corresponding scan-data is estimated in the direction in which, for correlated measure project large direction scan-data distribute less weight, for correlated measure project little direction scan-data distribute larger weight.

Impact point adopts following formulae discovery at the coordinate with reference to space:

$X_{\mathrm{usref}}^{\′}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\α}}_j(T_{\mathrm{usref}\_\mathrm{usj}}\·X_{\mathrm{usj}})$

Wherein, X ' _usrefbe the coordinate of impact point in reference space, N is the scanning times to same impact point, α _jthe weight vectors of jth time scan-data, T _{usred_usj}the transformation matrix of jth time ultrasonic scanning space to reference space, X _usjthe original coordinates of impact point in jth time ultrasonic scanning space.

According to a further aspect in the invention, a kind of object location device of 3 D ultrasound system is provided, for by impact point from ultrasonic scanning spatial alternation to world coordinates space, described device comprises: original coordinates obtains unit, for obtaining the coordinate of this impact point in ultrasonic scanning space when ultrasonic probe scans same impact point from different directions from the ultrasonoscopy of each scanning; Projecting cell, for selecting a ultrasonic scanning space as with reference to space, by all ultrasonic scanning space coordinatess of obtaining after Multiple-Scan to this reference space projection, obtains the transformation matrix of each ultrasonic scanning space coordinates to this reference space; Weight-assigning unit, for being that each scan-data assigns weight according to the correlated measure of all directions; Coordinate modification unit, for calculating impact point at the coordinate with reference to space according to weight and each ultrasonic scanning space coordinates to the transformation matrix in this reference space; Coordinate transformation unit, for utilize obtain in advance from ultrasonic scanning space to the transformation matrix in world coordinates space by impact point with reference to the coordinate transform in space to world coordinates space.

The present invention also provides a kind of 3 D ultrasound system simultaneously, comprising: ultrasonic probe, for launching ultrasound wave to those who are investigated's target site; Supersound process module, for the echo-signal received being processed, and obtains the ultrasonoscopy of target site; Caliberating device, for detecting the locator data of ultrasonic probe, and demarcates ultrasonoscopy and locator data, obtains the transformation matrix from ultrasonic scanning space to world coordinates space; Data computation module, for the data reconstruction that will demarcate or with other modal data registration, and export ultrasonoscopy and/or the data of target site, described data computation module comprises above-mentioned object location device; Display module, for showing the ultrasonoscopy of target site and data.

The present invention passes through ultrasonic scanning different directions correlated measure in reference projection spatially, distribute different weights, the axis higher with ultrasonic scanning spatial accuracy and lateral error make up the low thickness error of precision, thus improve the positioning precision of impact point in ultrasonic scanning space.

Accompanying drawing explanation

Fig. 1 is the block diagram of 3 D ultrasound system in an embodiment of the present invention;

Fig. 2 is the spatial transform relation of freedom-arm, three-D ultrasonic system in an embodiment of the present invention;

Fig. 3 is the structured flowchart of object location device in an embodiment of the present invention;

Fig. 4 is the positioning flow figure of impact point in an embodiment of the present invention;

Fig. 5 is Multiple-Scan impact point schematic diagram in an embodiment of the present invention.

Detailed description of the invention

By reference to the accompanying drawings the present invention is described in further detail below by detailed description of the invention.

In the embodiment of the application, sound field thickness factor taken into account, combined echocardiography axis and lateral error, by repetitive measurement impact point, give different weights, obtain the accurate world space coordinate of impact point simultaneously.When localizing objects point, ultrasonic probe carries out Multiple-Scan to same impact point from multiple directions, and the transformation matrix after at every turn being scanned between the coordinate of this impact point in ultrasonic scanning space and different coordinate space.By other ultrasonic scanning space coordinates ultrasonic scanning space projection (or by all ultrasonic scanning spaces to a new space projection) wherein, according to relevant the estimating (being called for short " correlated measure ") of certainty of measurement, be assigned to different weights, obtain after weighted sum revising rear impact point at the coordinate figure with reference to space.World coordinates is transformed to reference to spatial value again by revised, thus make up the low thickness error of precision by the higher axis of ultrasonic scanning spatial accuracy and lateral error, reduce the error of sound field thickness direction, the coordinate of the impact point obtained is also more accurate, improves follow-up ultrasonic fusion of imaging mid point to registration accuracy.

In a kind of embodiment, the block diagram of freedom-arm, three-D ultrasonic system as shown in Figure 1: 3 D ultrasound system comprises ultrasonic probe 101, supersound process module 104, caliberating device 100, data computation module 106 and display module 107.Ultrasonic probe 101 is for launching ultrasound wave to those who are investigated's target site; Supersound process module 104 for the echo-signal received being processed, and obtains the ultrasonoscopy of target site; Caliberating device 100, for carrying out three-dimensional scaling, namely passes through someway or device, determines the transformation relation between each space coordinates in 3 D ultrasound system.In one embodiment, caliberating device 100 comprises position sensor, register control and demarcating module, and position sensor is used for the positional information of detecting ultrasonic probe, such as, carry out detecting ultrasonic by magnetic or light and to pop one's head in the position sensor 102 of 101 locus.In one embodiment, position sensor 102 comprises an emitter and a receptor, the receptor of its Position Sensor 102 is fixed on probe 101, the emitter of position sensor 102 is then fixed near imaging position (diagnosis position), and along with the movement of probe, constantly provide positional information by the relative bearing between the receptor that records and emitter.Register control 103 is for obtaining the locus of ultrasonic probe according to the positional information of ultrasonic probe; Demarcating module 105 is for demarcating ultrasonoscopy and locator data.

Transformation relation between space coordinates comprises the transformation relation from ultrasonic scanning space to position sensor space, the transformation relation from position sensor space to world coordinates space, the spatial transform relation of freedom-arm, three-D ultrasonic system as shown in Figure 2.Space coordinate transformation closes:

X _w＝T _{w_s}·T _{s_us}·X _us-------------------------------(1)

Wherein X _usthe coordinate of point in ultrasonic scanning space, X _wthe coordinate of point at world's coordinate space, T _{s_us}the transformation matrix of ultrasonic scanning space to position sensor space, T _{w_s}the transformation matrix of position sensor space to world coordinates space.When position sensor is motionless on being fixed on and popping one's head in, ultrasound parameter is constant, T _{s_us}immobilize.T _{w_s}obtained by register control and position sensor, along with the movement of probe, T _{w_s}continuous change.

After knowing the transformation relation between each space coordinates, i.e. available ultrasonic scanning localizing objects point, the coordinate of ground point of plane of ultrasound is through coordinate transform, from ultrasonic scanning spatial alternation to position sensor space, transform to world space again, thus know the position of impact point at world's coordinate space.

Data computation module 106 namely for impact point that ultrasonic scanning is obtained from ultrasonic scanning spatial alternation to world coordinates space, for the data reconstruction that will demarcate or with other modal data registration, and export ultrasonoscopy and the data of target site; The ultrasonoscopy of the target site that data computation module 106 obtains and data and some functional parameters output to display module 107 and show.In embodiments of the present invention, data computation module 106 comprises object location device, and object location device is used for localizing objects point more accurately, thus more accurately by impact point from ultrasonic scanning spatial alternation to world coordinates space.

In prior art, in calibration process, do not consider the thickness of ultrasonic sound field, X _usthere is certain error, for making the impact point of acquisition more accurate at the coordinate in ultrasonic scanning space, in an embodiment of the present invention, as shown in Figure 3, object location device comprises original coordinates acquisition unit 301, projecting cell 302, weight-assigning unit 303, coordinate modification unit 304 and coordinate transformation unit 305.Original coordinates obtains unit 301 for obtaining the coordinate of impact point in ultrasonic scanning space from ultrasonoscopy when ultrasonic probe scans impact point from different directions; Projecting cell 302, for selecting a ultrasonic scanning space as with reference to space, by all ultrasonic scanning space coordinatess of obtaining after Multiple-Scan to this reference space projection, obtains the transformation matrix of each ultrasonic scanning space coordinates to this reference space; Weight-assigning unit 303 is for being that each scan-data assigns weight according to the correlated measure of all directions, in one embodiment, according to following regular allocation weight: weight in a direction (such as, axial direction, lateral or thickness direction) on component, determine according to corresponding scan-data correlated measure projected size in the direction in which, for the project scan-data in large direction of correlated measure distributes less weight, for the scan-data in the little direction of correlated measure distributes larger weight.Coordinate modification unit 304 is for calculating impact point at the coordinate with reference to space according to weight and each ultrasonic scanning space coordinates to the transformation matrix in this reference space; Coordinate transformation unit 305 utilizes the ultrasonic scanning space that obtains in advance to the transformation matrix T of position sensor space _{s_us}, and by caliberating device 100 obtain in advance from position sensor space to the transformation matrix T in world coordinates space _{w_s}, by impact point with reference to the coordinate transform in space to world coordinates space.

In one embodiment, impact point adopts following formulae discovery at the coordinate with reference to space:

$X_{\mathrm{usref}}^{\′}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\α}}_j(T_{\mathrm{usref}\_\mathrm{usj}}\·X_{\mathrm{usj}})---\left(2\right)$

Wherein, X ' _usrefbe the coordinate of impact point in reference space, N is scanning sum, α _jthe weight vectors of jth time scan-data, T _{usref_usj}the transformation matrix of jth time ultrasonic scanning space to reference space, X _usjthe original coordinates of impact point in jth time ultrasonic scanning space.Wherein, can be any one ultrasonic scanning space with reference to space, such as, can be the ultrasonic scanning space of certain scanning, also can be the new space of of haveing nothing to do with scanning direction.

Based on the 3 D ultrasound system of above-mentioned 3 D ultrasound system and object location device, in one embodiment, object location method as shown in Figure 4, comprises the following steps:

Step S1, from different directions, the same impact point of Multiple-Scan, namely each scanning direction forms a ultrasonic scanning space, the coordinate of impact point in this ultrasonic scanning space is obtained after each scanning, caliberating device 100 obtains the transformation matrix between each coordinate space simultaneously, and such as ultrasonic scanning space is to the transformation matrix of position sensor space, and position sensor space is to the transformation matrix in world coordinates space.Such as carry out N time scanning, N be greater than 1 integer.Scan mode can be twice sweep, and twice sweep direction is as far as possible vertical; Also can be repeatedly multiple directions scannings, each scanning direction at least run-down; Scanning direction can be divide equally as far as possible, also can be the ultrasonic scanning that any direction is not divided equally.

Step S2, in N scanning, select wherein once (such as i-th time) ultrasonic scanning space as reference space, by other N-1 time scanning coordinate to i-th ultrasonic scanning space projection, and obtain the transformation matrix of each ultrasonic scanning space coordinates to this reference space, wherein, N is scanning times, and i is the sequence number in the ultrasonic scanning space be projected, 1≤i≤N.

Step S3, gives different weights according to estimate (abbreviation correlated measure) relevant from certainty of measurement on each scanning direction to each scan-data.In different ultrasonic scanning spaces, different directions has different certainties of measurement, this is determined by the precision of instrument, correlated measure can be following physical quantity: error, variance or resolution, certainly, other the physical quantity relevant to certainty of measurement can also be defined as correlated measure by those skilled in the art as required.Give different weights according to correlated measure to scan-data, if correlated measure is comparatively large in this direction, then this direction should be made little on final result impact, and the weight of distribution should be less; If correlated measure is less in this direction, then this direction should be made large on final result impact, and the weight of distribution also should be larger.

Step S4, recalculates impact point in i-th ultrasonic scanning space namely with reference to the coordinate X ' in space according to weight and each ultrasonic scanning space coordinates to the transformation matrix in this reference space _usi.In one embodiment, new coordinate figure X ' is obtained by weighted sum _usi, shown in (2):

X′ _usi＝α ₁·(T _{usi_us1}·X _us1)+…+α _i·X _usi++…+α _N·(T _{usi_usN}·X _usN)-------(3)

Wherein: X ' _usithe correction coordinate of impact point in i-th ultrasonic scanning space, α ₁, α ₂... α _nthe weight vectors of each scan-data, T _{usi_usN}the N time ultrasonic scanning space obtaining in advance transformation matrix to i-th ultrasonic scanning space, X _usithe original coordinates of impact point in i-th ultrasonic scanning space.

For the situation that definition i-th ultrasonic scanning space is with reference to space, impact point is at the correction coordinate X ' in i-th ultrasonic scanning space _usibe impact point at the coordinate with reference to space.

Step S5, then use i-th scan conversion matrix, by impact point at the coordinate figure X ' with reference to space _usitransform to world coordinates space by formula (1), thus obtain impact point more accurate coordinate figure in world's coordinate space.

In one embodiment, be that scan-data gives different weights according to the inverse ratio of the projection of correlated measure (such as error/variance), divide be equipped with little weight for the correlated measure large direction that projects, large weight is distributed in the correlated measure little direction that projects, weight meets normalization, namely thus make large the estimating of error affect little on final result, what error was little estimates final result impact large, makes the impact point obtained revise coordinate in world's coordinate space more accurate.

For each ultrasonic scanning, inventor finds to there is following characteristics, that is: ultrasonic thickness directional precision is low, and precision that is axial and side direction is higher, therefore, the present embodiment carries out Multiple-Scan to same impact point from different directions, obtain the coordinate figure in the ultrasonic scanning space of impact point in each scanning, such as, as shown in Figure 5, if impact point is in the ultrasonic scanning of twice angled (such as 90 degree), in first time scanning, because thickness direction precision is low, accurately can not obtain thickness direction coordinate figure (namely perpendicular to the coordinate in scan plane direction), but in second time scanning, this direction is turned into side direction coordinate, because the precision of side direction is higher, therefore comparatively accurate coordinate figure can be obtained.In order to measurement result repeatedly can be combined, provide the result of a more high measurement accuracy, need each time to measure and unify to project in a public coordinate system, and assigned weight by correlated measure, recalculate the coordinate figure of this impact point, thus make up the low thickness error of precision by the higher axis of ultrasonic scanning spatial accuracy and lateral error, improve the positioning precision of impact point.

Illustrate how to calculate impact point at the coordinate with reference to space with a kind of instantiation below, as shown in Figure 5, repeat N the same impact point of scanning in a plurality of directions, obtain the coordinate figure X of impact point in i-th ultrasonic scanning space _usi={ X _usix, X _usiy, 0,1} ^t(wherein 1≤i≤N), caliberating device 100 obtains the transformation matrix T of position sensor to world coordinates _{w_si}, be fixed on position on probe due to position sensor and ultrasound parameter does not all change, so ultrasonic scanning space is to the transformation matrix T of position sensor space in scanning process _{s_us}immobilize.Suppose correlated measure δ _i=[δ _ix, δ _it, δ _iz] ^trepresent the lateral (x-axis) at impact point place during i-th ultrasonic scanning, axial direction (y-axis), the correlated measure of thickness direction (z-axis).Same δ _n=[δ _nx, δ _ny, δ _nz] ^twhen representing the N time ultrasonic scanning, the correlated measure of impact point place all directions.Because ultrasound data is at x, y, the precision correlated measure (such as error/variance) in z-axis and the degree of depth, frequency etc. various factors is relevant, δ _iand δ _nnot identical.Generally, lateral δ _x, axial direction δ _yless, thickness direction δ _zlarger.

Different directions has different certainties of measurement, such as axial direction, lateral and thickness direction have different certainties of measurement, different weights is given to scan-data according to correlated measure, such as, the projected size that the component of weight on axial direction, lateral or thickness direction is estimated in the direction in which according to corresponding scan-data is determined, for correlated measure project large direction scan-data distribute less weight, for correlated measure project little direction scan-data distribute larger weight.

New coordinate X ' is calculated by formula (2) _usi(coordinate under i-th ultrasonic scanning space (namely with reference to space)), X ' _usixfor X ' _usi=X ' _usix, X ' _usiy, X ' _usiz, 1} ^tx component, its computing formula is

X′ _usix＝α _1x·{T _{usi_us1}·X _us1} _x+…α _ix·X _usix+…+α _Nx·{T _{usi_usN}·X _usN} _x----------(4)

Wherein 0≤α _1x, α _2x... α _nx≤ 1, $\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\α}}_{\mathrm{ix}}=1,$ Order ${\mathrm{\α}}_{1x}=C_x\·\frac{1}{{\{B_1\·{\mathrm{\δ}}_1\}}_x},\·\·\·,{\mathrm{\α}}_{\mathrm{ix}}=C_x\·\frac{1}{{\mathrm{\δ}}_{\mathrm{ix}}},\·\·\·,$ ${\mathrm{\α}}_{\mathrm{Nx}}=C_x\·\frac{1}{{\{B_N\·{\mathrm{\δ}}_N\}}_x},$ Cx makes $\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\α}}_{\mathrm{ix}}=1$ Normalized parameter, { } _xrepresent the x component of vector.

$B_N=\left[\begin{array}{ccc}{r}_{N11}^2& r_{N12}^2& r_{N13}^2\\ r_{N21}^2& r_{N22}^2& r_{N23}^2\\ r_{N31}^2& r_{N12}^2& r_{N33}^2\end{array}\right]$ T _{usi_usN}spin matrix $R_N={\left[\begin{array}{ccc}{r}_{N11}& r_{N12}& r_{N13}\\ r_{N21}& r_{N22}& r_{N23}\\ r_{N31}& r_{N12}& r_{N33}\end{array}\right]}_{3*3}$ Square matrix formed of respective value.

Y-axis can be obtained equally, the new coordinate figure X ' in z-axis _usiy, X ' _usiz, finally obtain the coordinate X ' of new rectification _usi, X ' now _usiz-axis direction value X ' _usizcan be non-vanishing.

X′ _w＝T _{w_si}·T _{s_us}·X′ _usi----------------(5)

Wherein T _{s_us}the transformation matrix of ultrasonic scanning space to position sensor space, T _{w_si}when being i-th ultrasonic scanning, position sensor space is to the transformation matrix in world coordinates space.Through type (4), by corrected for impact point i-th ultrasonic scanning spatial value X ' _usitransform to world coordinates space, obtain the world space coordinate X ' of more accurate impact point _w.X ' _usiz-axis direction value X ' _usizlikely non-vanishing, by the conversion between original two-dimensional ultrasound plane to three-dimensional position sensing device coordinate system, expand to the conversion between certain thickness ultrasonic acoustic beam face to three-dimensional position sensing device space.By the projection of correlated measure, distribute different weights, the axis higher with ultrasonic scanning spatial accuracy and lateral error make up the low thickness error of precision, improve the positioning precision of impact point.

In freedom-arm, three-D ultrasonic system one of object location typically application be the right registration of ultrasonic fusion of imaging mid point.A step important in ultrasonic fusion of imaging is the demarcation registration by ultrasonoscopy and another modal data, it is mapped with the position of impact point in another modal data the position of impact point in world coordinates, the raising of extraterrestrial target spot placement accuracy, greatly can improve registration accuracy, thus improve the quality of ultrasonic fusion of imaging.The data of another mode can be the imaging datas such as CT, MRI.

In another embodiment, from different directions after Multiple-Scan impact point, one is selected to be different from the new ultrasonic scanning space of of arbitrary scanning direction as with reference to space, by all ultrasonic scanning space coordinatess of obtaining after Multiple-Scan to this reference space projection, obtain the transformation matrix of each ultrasonic scanning space coordinates to this reference space, same is that each scan-data assigns weight according to the correlated measure of all directions, then the coordinate of impact point in this reference space is calculated according to weight and each ultrasonic scanning space coordinates to the transformation matrix in this reference space, its computing formula is:

X′ _usnew＝α ₁·(T _{usnew_us1}·X _us1)+…+α _i(T _{usnew_usi}·X _usi)++…+α _N·(T _{usnew_usN}·X _usN)---(6)

Wherein: X ' _usnewthe correction coordinate of impact point in reference space, α ₁, α ₂... α _nthe weight vectors of each the scan-data calculated according to correlated measure, T _{usnew_usN}the N time ultrasonic scanning space transformation matrix to this new space, X _usithe original coordinates of impact point in i-th ultrasonic scanning space.

In the above-described embodiments, the correlated measure on different directions can also be resolution, also can be the ultrasonic distributed data that water listens instrument to measure.Correlated measure can be set-point as δ _x=1, δ _y=1.5, δ _z=3.Also can be degree of depth l, wavelength X, the isoparametric function of first geometry D that shakes be as δ _x=f _x(l, λ, D), δ _y=f _y(l, λ, D), δ _z=f _z(l, λ, D), such as δ _x=k _x* l* λ, δ _y=k _y* λ, δ _z=k _z* cos (λ/D), wherein kx, ky, kz be certainty of measurement in all directions relevant estimate parameter.

In above-described embodiment, meet according to the weight that correlated measure distributes α _ix≤ 1, α _ican also be other forms, such as α _ifor the function alpha of correlated measure during each scanning impact point, each transformation matrix _ix=f (δ ₁, δ ₂..., δ _n, T _{us1_us2}..., T _{us1_usN}), such as or deng.

In above-described embodiment, position sensor can be the position sensor based on electromagnetic induction, also can be the position sensor based on optical principle, also can be other position sensor such as grade based on Principles of Acoustics.

Above content is in conjunction with concrete embodiment further description made for the present invention, can not assert that specific embodiment of the invention is confined to these explanations.For general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, some simple deduction or replace can also be made, all should be considered as belonging to protection scope of the present invention.

Claims (10)

1. an object location method for 3 D ultrasound system, is characterized in that comprising:

Obtain the coordinate of this impact point in each ultrasonic scanning space when ultrasonic probe repeatedly scans same impact point from different directions;

Select a ultrasonic scanning space as with reference to space, by all ultrasonic scanning space coordinatess of obtaining after Multiple-Scan to this reference space projection, obtain the transformation matrix of each ultrasonic scanning space coordinates to this reference space;

According to relevant the estimating for each time of the certainty of measurement of all directions, scan-data assigns weight;

Impact point is calculated at the coordinate with reference to space to the transformation matrix in this reference space according to weight and each ultrasonic scanning space coordinates;

Utilize obtain in advance from ultrasonic scanning space to the transformation matrix in world coordinates space by impact point with reference to the coordinate transform in space to world coordinates space.

2. the method for claim 1, is characterized in that, relevant the estimating for error, variance or resolution of described certainty of measurement.

3. the method for claim 1, it is characterized in that, what the described certainty of measurement according to all directions was relevant estimate for scan for each time assign weight time according to following rule: the component of weight on axial direction, lateral or thickness direction, determine according to the projected size that corresponding scan-data is estimated in the direction in which, the scan-data in the direction that the measure projection of being correlated with for certainty of measurement is large distributes less weight, and the scan-data in the direction that the measure projection of being correlated with for certainty of measurement is little distributes larger weight.

4. method as claimed any one in claims 1 to 3, is characterized in that, impact point adopts following formulae discovery at the coordinate with reference to space:

${X^{\′}}_{\mathrm{usref}}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{\α}}_j(T_{\mathrm{usref}\_\mathrm{usj}}\·X_{\mathrm{usj}})$

Wherein, X' _usrefbe the coordinate of impact point in reference space, N is the scanning times to same impact point, α _jthe weight vectors of jth time scan-data, T _{usref_usj}the transformation matrix of jth time ultrasonic scanning space to reference space, X _usjthe original coordinates of impact point in jth time ultrasonic scanning space.

5. method as claimed in claim 4, is characterized in that, described is be different from the new space of of scanning direction with reference to space; Or described is the ultrasonic scanning space that in Multiple-Scan, certain scans with reference to space.

6. an object location device for 3 D ultrasound system, for by impact point from ultrasonic scanning spatial alternation to world coordinates space, it is characterized in that described device comprises:

Original coordinates obtains unit, for obtaining the coordinate of this impact point in ultrasonic scanning space when ultrasonic probe scans same impact point from different directions from the ultrasonoscopy of each scanning;

Projecting cell, for selecting a ultrasonic scanning space as with reference to space, by all ultrasonic scanning space coordinatess of obtaining after Multiple-Scan to this reference space projection, obtains the transformation matrix of each ultrasonic scanning space coordinates to this reference space;

Weight-assigning unit, for according to relevant the estimating for each time of the certainty of measurement of all directions, scan-data assigns weight;

Coordinate modification unit, for calculating impact point at the coordinate with reference to space according to weight and each ultrasonic scanning space coordinates to the transformation matrix in this reference space;

Coordinate transformation unit, for utilize obtain in advance from ultrasonic scanning space to the transformation matrix in world coordinates space by impact point with reference to the coordinate transform in space to world coordinates space.

7. device as claimed in claim 6, is characterized in that, relevant the estimating for error, variance or resolution of described certainty of measurement.

8. device as claimed in claims 6 or 7, it is characterized in that, what the described certainty of measurement according to all directions was relevant estimate for scan for each time assign weight time according to following rule: the component of weight on axial direction, lateral or thickness direction, determine according to the projected size that corresponding scan-data is estimated in the direction in which, the scan-data in the direction that the measure projection of being correlated with for certainty of measurement is large distributes less weight, and the scan-data in the direction that the measure projection of being correlated with for certainty of measurement is little distributes larger weight.

9. device as claimed in claim 8, is characterized in that, impact point adopts following formulae discovery at the coordinate with reference to space:

X' _usref＝α ₁(T _{usref_us1}·X _us1)+…+α _i(T _{usref_usi}·X _usi)++…+α _N(T _{usref_usN}·X _usN)

Wherein, X' _usrefthe coordinate of impact point in reference space, α ₁, α ₂... α _nthe weight vectors of each scan-data, T _{usref_usN}be the N time ultrasonic scanning space to the transformation matrix with reference to space, X _usithe original coordinates of impact point in i-th ultrasonic space.

10. a 3 D ultrasound system, is characterized in that, comprising:

Ultrasonic probe, for launching ultrasound wave to those who are investigated's target site;

Supersound process module, for the echo-signal received being processed, and obtains the ultrasonoscopy of target site;

Caliberating device, for detecting the locator data of ultrasonic probe, and demarcates ultrasonoscopy and locator data, obtains the transformation matrix from ultrasonic scanning space to world coordinates space;

Data computation module, for the data reconstruction that will demarcate or with other modal data registration, and export ultrasonoscopy and/or the data of target site, described data computation module comprises the object location device according to any one of power 6 to 9;

Display module, for showing the ultrasonoscopy of target site and data.