CN105662408A - Multi-mode microwave imaging method and system - Google Patents

Abstract

The invention relates to a multi-mode microwave imaging method and system. Pixel points of one of a radar detection image and a tomoscan image is mapped to another image, relevant pixel points of the two images are consistent in spatial positions, and the fusion of the two images is completed. During the diagnosis process of early-stage cancer patients, different imaging modes can be used for complementary advantages. According to the invention, two technologies are fused successfully, a multi-mode microwave breast imaging system is formed, and imaging advantages and disadvantages are complementary.

Description

A kind of multi-modal microwave imaging method and system

Technical field

The present invention relates to the fusion method of a kind of image and system, particularly relate to fusion method and the system of a kind of radar detection image and tomoscan image.

Background technology

In medical treatment detection process, generally include X-ray and take the photograph sheet, color ultrasound, magnetic resonance and histology. X-ray takes the photograph chip resolution height, but along with ionizing radiation and the compression to breast, is not suitable for the generaI investigation of patient. Color ultrasound detects "dead" infringement, but part cancer sufferer, calcification point and burr poplar structure can not be shown, and big by inspecting doctor's experience influence. Costly, imaging time is of a specified duration, and histological examination also needs to be accurately positioned in magnetic resonance, as molybdenum target be inducted into pin, color ultrasound guidance enters pin etc. Therefore, these current detection meanss are not particularly suited for large-scale cancer sufferer examination, in particular for the rural area that China is vast, under medical facilities and universal very unbalanced condition, and the Clinical detection of microwave imaging have, effect low without ionizing radiation, cost and X-ray quite, can long term monitoring feature, it is possible to become me and cross the important tool of extensive examination.

In microwave Imaging Technique, include two kinds of technology, microwave radar imaging and microwave Tomography, the former is for contrasting breast tissue clearly, can be good at finding strong scattering region, meet X-ray and ultrasonic and MRI judgement, very fine and close breast is difficult to understand, and for benign tumor, or some tissue cakings, equally can provide and misread, microwave Tomography then may determine that the dense type of tissue, may determine that the region of different tissues, two kinds of formation methods are respectively arranged with advantage but are difficult to unified simultaneously.

Summary of the invention

Present invention solves the technical problem that and be: build a kind of multi-modal microwave imaging method and system, overcome prior art single detection device two kinds of images can not be carried out unified technical problem.

A kind of multi-modal microwave imaging method of offer is provided, comprises the steps:

Microwave Scanning: region to be measured is occurred microwave broadband pulse signal and microwave single-frequency coherent signal; Receive microwave broadband pulse echo signal and microwave single-frequency echo-signal;

Imaging respectively: generate radar detection image according to microwave broadband pulse echo signal, according to microwave single-frequency echo signal form tomoscan image;

Image co-registration: the pixel of piece image in described radar detection image and described tomoscan image is mapped in another piece image and merges.

The further technical scheme of the present invention is: be mapped in another piece image by the pixel of piece image in described radar detection image and described tomoscan image, makes the fusion reaching unanimously to complete this two width image related like vegetarian refreshments on locus of two width images.

The further technical scheme of the present invention is: in described radar detection image and described tomoscan image, the characteristic point place of image carries out labelling, the image tagged of described radar detection image and described tomoscan image is overlapped described radar detection image and described tomoscan image are merged, the image tagged of described radar detection image and described tomoscan image is identified, then identification image is carried out image co-registration as boundary mark.

The further technical scheme of the present invention is: in image co-registration step, and the image pixel weighted average of described radar detection image and described tomoscan image correspondence position is completed image co-registration.

The further technical scheme of the present invention is: after carrying out labelling, image is optimized.

The technical scheme is that a kind of multi-modal microwave imaging system of structure, including microwave signal generating unit, microwave signal receives unit, radar imagery unit, Tomography unit, fusion treatment unit, be there is microwave broadband pulse signal and microwave single-frequency coherent signal by described microwave signal generating unit in region to be measured, described microwave signal receives unit and receives microwave broadband pulse echo signal and microwave single-frequency echo-signal, described radar imagery unit generates radar detection image according to microwave broadband pulse echo signal, described Tomography unit is according to microwave single-frequency echo signal form tomoscan image, described radar detection image and described tomoscan image are merged by described fusion treatment unit.

The further technical scheme of the present invention is: described fusion treatment unit also includes image tagged module, described image tagged module characteristic point place of image in described radar detection image and described tomoscan image carries out labelling, the image tagged of described radar detection image and described tomoscan image is overlapped and described radar detection image and described tomoscan image are merged.

The further technical scheme of the present invention is: described fusion treatment unit also includes image tagged identification module, and the image tagged of described radar detection image and described tomoscan image is identified by described image tagged identification module.

The further technical scheme of the present invention is: also including image optimization module, the image after labelling is optimized by described image optimization module.

The further technical scheme of the present invention is: microwave signal generating unit is multiple, and microwave broadband pulse signal and microwave single-frequency coherent signal occur respectively; Or microwave signal generating unit is one, alternately there is microwave broadband pulse signal and microwave single-frequency coherent signal.

The solution have the advantages that: build a kind of multi-modal microwave imaging method and system, by being mapped in another piece image by the pixel of piece image in described radar detection image and described tomoscan image, make the fusion reaching unanimously to complete this two width image related like vegetarian refreshments on locus of two width images. Can by using different image modes to have complementary advantages in the process of diagnosis earlier stage cancer patients, microwave radar imaging utilizes ultra-wideband microwave signal to obtain target scattering center high-resolution in distance, then doppler information is utilized, obtain scattering center high-resolution in lateral separation, in combination with two dimension or the dimensional resolution that can obtain target, so that the multidigit high-resolution of target is achieved. Microwave Tomography is by low power microwave directive testee, under the excitation of microwave, measured object produces a scattered field, this scattered field is relevant with the complex dielectric permittivity distribution within measured object, by the measurement to this scattering, obtain the relative dielectric constant of measured object and the distribution of electrical conductivity, the microwave wave circuits and systems of measured object internal object after carrying out corresponding information processing, can be obtained. By both technology successful fusion in the present invention, constitute a set of multi-mode microwave breast imaging system, reach the purpose that imaging quality is complementary.

Accompanying drawing explanation

Fig. 1 is the structural representation of the present invention.

Fig. 2 is the structure chart of the present invention.

Fig. 3 is the fusion flow chart of the present invention.

Detailed description of the invention

Below in conjunction with specific embodiment, technical solution of the present invention is further illustrated.

As it is shown in figure 1, the specific embodiment of the present invention is: provide a kind of multi-modal microwave imaging method, comprise the steps:

Microwave Scanning: region to be measured is occurred microwave broadband pulse signal and microwave single-frequency coherent signal; Receive microwave broadband pulse echo signal and microwave single-frequency echo-signal;

Specific implementation process is as follows: region to be measured microwave broadband pulse signal is occurred by microwave antenna unit by microwave generating unit, microwave broadband pulse signal irradiates the focal area in imaging region, produce scattering on surface, focal area, receive the microwave broadband pulse echo signal from focus surface scattering with the scanning of several microwave antenna units. There is microwave single-frequency coherent signal by microwave antenna unit to region to be measured in microwave generating unit, microwave antenna unit scanning receives and records the microwave single-frequency echo-signal of position. Microwave Scanning antenna alternately realizes signal and launches and receive; Or microwave transmitting antenna and microwave antenna are array arrangement, carry out launching microwave signal and receiving microwave echoes signal microwave signal generating unit is multiple signal generator simultaneously, provides microwave broadband pulse signal and microwave single-frequency coherent signal for system.

Imaging respectively: generate radar detection image according to microwave broadband pulse echo signal, according to microwave single-frequency echo signal form tomoscan image.

Specific implementation process is as follows: microwave radar image-forming principle utilizes theory of SAR, using a miniature antenna as single radiating element, the continuous motion scan in direction along a straight line, movement select some positions launch signal, receiving the corresponding echo-signal launching position, storage receives amplitude and the phase place of signal. Received the time of microwave scattering signal by microwave antenna unit record, time delay can be calculated, and the distance of microwave antenna unit and focus is fixed, therefore micro-transmitting antenna distance to focus can be obtained, thus carrying out accurate imaging. Microwave wave circuits and systems method is similar to computed tomography (CT), it it is a kind of THE INVERSE ELECTROMAGNETIC SCATTERING method, by scattering object external observation to electromagnetic field carry out the electromagnetic signature parameter distribution in inversion imaging region, thus judging the information such as the position of scattering object target, shape and size distribution. The microwave single-frequency echo-signal that will receive, according to electromagnetic signature parameter distribution and the position of scattering object target, shape and size distributed intelligence generation tomoscan image.

Image co-registration: be mapped in another piece image by the pixel of piece image in described radar detection image and described tomoscan image, makes the fusion reaching unanimously to complete this two width image related like vegetarian refreshments on locus of two width images.

Specific implementation process is as follows: image co-registration includes multiple method: a kind of method is labelling method, in described radar detection image and described tomoscan image, the characteristic point place of image carries out labelling, the image tagged of described radar detection image and described tomoscan image is overlapped described radar detection image and described tomoscan image are merged, when image co-registration, the image tagged of described radar detection image and described tomoscan image is identified, then identification image is carried out image co-registration as boundary mark, identify image tagged feature, image co-registration can be made more accurate. in specific embodiment, after carrying out labelling, image is optimized, after segmentation, cut zone is carried out image co-registration. image tagged software design becomes the boundary mark synthesized by the Feature point recognition of image as image. image tagged software is according to labelling to the labelling of tissue identification, the labelling of lymph node identification and characteristic of described radar detection image and tomoscan image, coordinate axes is formed coincidence point, completing the fusion of described radar detection image and tomoscan image, the method is equally applicable to two dimension or the three-dimensional breast image that other modes combine. further comprises the display to multi-modal microwave breast image, the two and three dimensions information of display breast, the labelling to focal area. another kind of method is pixel weighted mean method, it may be assumed that the image pixel weighted average of described radar detection image and described tomoscan image correspondence position is completed image co-registration.

Below for labelling method:

Image registration

By using coupling, superposition etc. to process means, the same target in multiple image is kept same position in the picture so that it is there is the process of identical space coordinates.

In the microwave tomoscan image registration with microwave radar image, using metastable microwave tomoscan image as reference picture I, using microwave radar image as floating image II, carry out the image registration of the maximum mutual information method based on pixel, flow chart as shown in Figure 3 under:

Rigid body translation includes transformation of scale, in two-dimensional image I I, and point (x₁, y₁) through rigid transformation to point (x₂, y₂) application formula be:

$\left[\begin{array}{c}{x}_2\\ y_2\end{array}\right]=K\left[\begin{array}{cc}cos\mathrm{\α}& \±sin\mathrm{\α}\\ sin\mathrm{\α}& \±cos\mathrm{\α}\end{array}\right]\left[\begin{array}{c}{x}_1\\ y_1\end{array}\right]---\left(1\right)$

Wherein, α is the anglec of rotation, and K is scale parameter.

Mutual information relevance evaluation. The gray value of two images subject to registration is regarded as two stochastic variable A and B respectively, and scope 0 to 255, marginal probability distribution is P respectively_A(a) and P_BB (), joint probability distribution is P_AB(a, b), then edge entropy and the combination entropy that can obtain A and B are respectively as follows: H (A), H (B) and H (A, B). Then have:

$\left\{\begin{array}{c}H\left(A\right)=-\underset{a}{\Σ}{P}_A\left(a\right){\mathrm{logP}}_A\left(a\right)\\ H\left(B\right)=-\underset{b}{\Σ}{P}_B\left(b\right){\mathrm{logP}}_B\left(b\right)\\ H(A,B)=-\underset{a}{\Σ}\underset{b}{\Σ}{P}_{AB}(a,b){\mathrm{logP}}_{AB}(a,b)\end{array}\right.,a,b\∈\[0,255\]---\left(2\right)$

Normalized mutual information dependent evaluation function I (A, B) of stochastic variable A and B, for:

$I(A,B)=\frac{H\left(A\right)+H\left(B\right)}{H(A,B)}---\left(3\right)$

When two width reach optimal registration based on the image of common anatomical structure, gray scale cross-correlation value of information I (A, B) of they respective pixel should reach maximum.

Registration optimizes. After rigid body translation completes, a kind of similarity side degree need to be found further to weigh the similarity degree of two width images, it is necessary to constantly transformation parameter α and K so that similar side degree reaches optimum, wherein scale parameter K excursion is 0 to 1, and rotation angle range is 0 to 180 degree.

1. it is the unit vector of coordinate axes: c by α and K transformation range set_i=e (i=1,2 ..., N);

2. record initial value position vector is P₀=(α₀, K₀);

3. to i=1,2 ..., N, by P_i‐1Move to object function I (A, B) and prolong c_iThe maximum position in direction, writes down this P_i;

4. to i=1,2 ..., N, by c_i+1It is assigned to c_i, juxtaposition c_N=P_N‐P₀;

5. by P_NMove to object function I (A, B) at c_NMaximum point on direction, and record the P of this point₀;

6. repeat step 2. to arrive 5., until functional value I (A, B) no longer increases.

The preferred embodiment of the present invention is: also included carrying out Image semantic classification before carrying out image co-registration.

Microwave tomoscan image preprocess method is as follows: big by external interference factor based on microwave Tomography, Image semantic classification we utilize point processing to carry out the extension of contrast, making image clear, feature is obvious, it is assumed that original image f (x, y) tonal range is [a, b], and image g after conversion (x, what tonal range y) was linear extends to [c, d], then there is grey linear transformation expression formula is:

$g(x,y)=\frac{d-c}{b-a}\×\[f(x,y)-a\]+c$

When the grey level distribution of pixel most of in image is in interval [a, b], f_maxFor the maximum gray scale of artwork, only the gray level of very small part has exceeded this interval, then in order to improve reinforced effects, and Wo Menling

$g(x,y)=\left\{\begin{array}{cc}c& 0\≤f(x,y)\≤a\\ \frac{d-c}{b-a}\×\[f(x,y)-a\]+c& a\≤f(x,y)\≤b\\ d& b\≤f(x,y)\≤f_{max}\end{array}\right.$

By the linear stretch to image, it is possible to be effectively improved picture contrast effect.

Microwave radar image pre-processing method is as follows: owing to microwave radar imaging is except the intrinsic problem speckle noise existed, and there is also the bright spot high-frequency noise of random appearance simultaneously, and we utilize low pass Recursive filtering method that it is carried out pretreatment.

Assume the grey decision-making x of each pixel in the n-th width microwave radar image_n(i j) represents, α is correlation coefficient, then the image y after processing_n(i j) is

y_n(i, j)=α * y_n‐1(i, j)+(1 α) * x_n(i, j) (4)

It is appreciated that by formula (4), the value of current each pixel is solely dependent upon the input of this pixel and the output of last time, unrelated with the value of other pixels, and we analyze its frequency characteristic by one-dimensional transform method, analyze the frequency response of each pixel self, namely have:

Y (n)=α * y (n 1)+(1 α) * x (n) (5)

Its transmission function is,

H (z)=Y (z)/X (z)=(1 α)/(1 α z^‐1)(6)

In l-G simulation test, value α is the amplitude-frequency characteristic of 0.2,0.6 and 0.8, and α value is more big, and radio-frequency component is repressed more severe, weakens speckle noise more obvious.

Such as Fig. 1, shown in Fig. 2, the specific embodiment of the present invention is: the present invention builds a kind of multi-modal microwave imaging system, including microwave signal generating unit 1, microwave signal receives unit 2, radar imagery unit 3, Tomography unit 4, fusion treatment unit 5, be there is microwave broadband pulse signal and microwave single-frequency coherent signal by described microwave signal generating unit 1 in region to be measured, described microwave signal receives unit 2 and receives microwave broadband pulse echo signal and microwave single-frequency echo-signal, described radar imagery unit 3 generates radar detection image according to microwave broadband pulse echo signal, described Tomography unit 4 is according to microwave single-frequency echo signal form tomoscan image, the pixel of piece image in described radar detection image and described tomoscan image is mapped in another piece image and merges by described fusion treatment unit 5.

Specific implementation process is as follows: microwave broadband pulse signal and microwave single-frequency coherent signal are occurred by described microwave signal generating unit 1 for region to be measured, and described microwave signal receives unit 2 and receives microwave broadband pulse echo signal and microwave single-frequency echo-signal. Described microwave signal generating unit 1 includes microwave generator and microwave transmitting antenna, and described microwave signal receives unit 2 and includes microwave antenna, and microwave antenna includes microwave transmitting antenna and microwave antenna. Microwave broadband pulse signal is there is by microwave signal generating unit 1 in region to be measured by microwave antenna, microwave broadband pulse signal irradiates the focal area in imaging region, produce scattering on surface, focal area, receive the signal from focus surface scattering with the scanning of several microwave antennas. There is microwave single-frequency coherent signal by microwave antenna to region to be measured in microwave signal generating unit 1, microwave antenna scanning receives and records the microwave broadband pulse echo signal of position. Microwave transmitting antenna and microwave antenna can be same microwave antenna, are used alternatingly; Microwave transmitting antenna and microwave antenna can also respectively different microwave antennas, carry out respectively launching microwave signal and receiving microwave echoes signal using. Microwave signal generating unit is multiple, and microwave broadband pulse signal and microwave single-frequency coherent signal occur respectively; Or microwave signal generating unit is one, alternately there is microwave broadband pulse signal and microwave single-frequency coherent signal. Microwave radar image-forming principle utilizes theory of SAR, using a miniature antenna as single radiating element, the continuous motion scan in direction along a straight line, select some positions to launch signal in movement, receiving the corresponding echo-signal launching position, storage receives amplitude and the phase place of signal. Received the time of microwave broadband pulse echo signal by microwave antenna record, time delay can be calculated, and the distance of microwave transmitting antenna and focus is fixed, therefore micro-transmitting antenna distance to focus can be obtained, thus carrying out accurate imaging. Microwave wave circuits and systems method is similar to computed tomography (CT), it it is a kind of THE INVERSE ELECTROMAGNETIC SCATTERING method, by scattering object external observation to electromagnetic field carry out the electromagnetic signature parameter distribution in inversion imaging region, thus judging the information such as the position of scattering object target, shape and size distribution. The microwave single-frequency echo-signal that will receive, according to electromagnetic signature parameter distribution and the position of scattering object target, shape and size distributed intelligence generation tomoscan image. The pixel of piece image in described radar detection image and described tomoscan image is mapped in another piece image by described fusion treatment unit 5, makes the fusion reaching unanimously to complete this two width image related like vegetarian refreshments on locus of two width images.

Image co-registration includes multiple method: a kind of method is labelling method, described fusion treatment unit 5 also includes image tagged module 51, image tagged identification module 52, image optimization module 53, described image tagged module 51 characteristic point place of image in described radar detection image and described tomoscan image carries out labelling, the image tagged of described radar detection image and described tomoscan image is overlapped and described radar detection image and described tomoscan image are merged. The image tagged of described radar detection image and described tomoscan image is identified by described image tagged identification module 52. Image after labelling is optimized by described image optimization module, after segmentation, cut zone is carried out image co-registration. When image co-registration, the image tagged of described radar detection image and described tomoscan image is identified, then identification image is carried out image co-registration as boundary mark. In specific embodiment, after carrying out labelling, image is optimized. Image tagged software design becomes the boundary mark synthesized by the Feature point recognition of image as image. Image tagged software is according to labelling to the labelling of tissue identification, the labelling of lymph node identification and characteristic of described radar detection image and tomoscan image, coordinate axes is formed coincidence point, completing the fusion of described radar detection image and tomoscan image, the method is equally applicable to two dimension or the three-dimensional breast image that other modes combine. Further comprises the display to multi-modal microwave breast image, the two and three dimensions information of display breast, the labelling to focal area. Another kind of method is pixel weighted mean method, it may be assumed that the image pixel weighted average of described radar detection image and described tomoscan image correspondence position is completed image co-registration.

The preferred embodiment of the present invention is: described microwave antenna constitutes aerial array. Aerial array can meet the demand of microwave radar imaging and microwave Tomography simultaneously, and aerial array entirety is hemispherical 32 the dual-mode antenna unit turned to towards half ball center. Aerial array is divided into transmitting and receiving unit, alternately arranging at equal intervals, corresponding two an of transmitting element receives unit, staggered transmitting-receiving, being controlled aerial array by microwave control unit and launch microwave radar detectable signal continuously to measured target, control mode is single pole multiple throw. Microwave control unit provides cline frequency ripple to microwave switch aerial array, and operating frequency range is 1 to 30GHz.

The solution have the advantages that: build a kind of multi-modal microwave imaging method and system, by being mapped in another piece image by the pixel of piece image in described radar detection image and described tomoscan image, make the fusion reaching unanimously to complete this two width image related like vegetarian refreshments on locus of two width images. Can by using different image modes to have complementary advantages in the process of diagnosis earlier stage cancer patients, microwave radar imaging utilizes ultra-wideband microwave signal to obtain target scattering center high-resolution in distance, then doppler information is utilized, obtain scattering center high-resolution in lateral separation, in combination with two dimension or the dimensional resolution that can obtain target, so that the multidigit high-resolution of target is achieved. Microwave Tomography is by low power microwave directive testee, under the excitation of microwave, measured object produces a scattered field, this scattered field is relevant with the complex dielectric permittivity distribution within measured object, by the measurement to this scattering, obtain the relative dielectric constant of measured object and the distribution of electrical conductivity, the microwave wave circuits and systems of measured object internal object after carrying out corresponding information processing, can be obtained. By both technology successful fusion in the present invention, constitute a set of multi-mode microwave breast imaging system, reach the purpose that imaging quality is complementary.

Above content is in conjunction with concrete preferred implementation further description made for the present invention, it is impossible to 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, it is also possible to make some simple deduction or replace, protection scope of the present invention all should be considered as belonging to.

Claims (10)

1. a multi-modal microwave imaging method, comprises the steps:

Microwave Scanning: region to be measured is occurred microwave broadband pulse signal and microwave single-frequency coherent signal; Receive microwave broadband pulse echo signal and microwave single-frequency echo-signal;

Imaging respectively: generate radar detection image according to microwave broadband pulse echo signal, according to microwave single-frequency echo signal form tomoscan image;

Image co-registration: the pixel of piece image in described radar detection image and described tomoscan image is mapped in another piece image and merges.

2. multi-modal microwave imaging method according to claim 1, it is characterized in that, the pixel of piece image in described radar detection image and described tomoscan image is mapped in another piece image, makes the fusion reaching unanimously to complete this two width image related like vegetarian refreshments on locus of two width images.

3. multi-modal microwave imaging method according to claim 1, it is characterized in that, in described radar detection image and described tomoscan image, the characteristic point place of image carries out labelling, the image tagged of described radar detection image and described tomoscan image is overlapped described radar detection image and described tomoscan image are merged, the image tagged of described radar detection image and described tomoscan image is identified, then identification image is carried out image co-registration as boundary mark.

4. multi-modal microwave imaging method according to claim 1, it is characterised in that in image co-registration step, the image pixel weighted average of described radar detection image and described tomoscan image correspondence position is completed image co-registration.

5. multi-modal microwave imaging method according to claim 1, it is characterised in that after carrying out labelling, image is optimized.

6. a multi-modal microwave imaging system, it is characterized in that, including microwave signal generating unit, microwave signal receives unit, radar imagery unit, Tomography unit, fusion treatment unit, be there is microwave broadband pulse signal and microwave single-frequency coherent signal by described microwave signal generating unit in region to be measured, described microwave signal receives unit and receives microwave broadband pulse echo signal and microwave single-frequency echo-signal, described radar imagery unit generates radar detection image according to microwave broadband pulse echo signal, described Tomography unit is according to microwave single-frequency echo signal form tomoscan image, the pixel of piece image in described radar detection image and described tomoscan image is mapped in another piece image and merges by described fusion treatment unit.

7. multi-modal microwave imaging system according to claim 6, it is characterized in that, described fusion treatment unit also includes image tagged module, described image tagged module characteristic point place of image in described radar detection image and described tomoscan image carries out labelling, the image tagged of described radar detection image and described tomoscan image is overlapped and described radar detection image and described tomoscan image are merged.

8. multi-modal microwave imaging system according to claim 7, it is characterized in that, described fusion treatment unit also includes image tagged identification module, and the image tagged of described radar detection image and described tomoscan image is identified by described image tagged identification module.

9. multi-modal microwave imaging system according to claim 7, it is characterised in that also including image optimization module, the image after labelling is optimized by described image optimization module.

10., there is microwave broadband pulse signal and microwave single-frequency coherent signal respectively in multi-modal microwave imaging system according to claim 6, it is characterised in that microwave signal generating unit is multiple; Or microwave signal generating unit is one, alternately there is microwave broadband pulse signal and microwave single-frequency coherent signal.