CN100484468C - High sensitivity open type magnetic induction image measuring device - Google Patents
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- CN100484468C CN100484468C CNB200710092746XA CN200710092746A CN100484468C CN 100484468 C CN100484468 C CN 100484468C CN B200710092746X A CNB200710092746X A CN B200710092746XA CN 200710092746 A CN200710092746 A CN 200710092746A CN 100484468 C CN100484468 C CN 100484468C
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Abstract
The present invention relates to an open-typed magnetic induction imaging measuring device, consisting of a controller, an actuating single passage, an offset signal passage, a power magnifying circuit, a relay array, a winding sensor array, an array of difference amplifying circuits, a switch array, a signal regulating circuit, a signal amplifying and signal regulating circuit, a signal scale adjusting circuit, an A/D transferring circuit, a circuit for limiting drift of switch temperature and an external communication port. Imaging of the present invention is relatively simpler than global imaging, while requirement about hardware system in imaging of the present invention is lower than that of the global imaging, which means lower parameters about passage values which activate the signals. The present invention can satisfy needs of clinical medicine toward small sized, cheap, noninvasive and quick test instrument and imaging equipment with function of real time monitor.
Description
Technical field
The present invention relates to medical imaging diagnosis equipment, particularly a kind of highly sensitive open type magnetic induction image measuring device.
Background technology
Since X ray was found, medical science and clinical medical development had produced qualitative leap.In the period of surplus in the of particularly nearly 20, traditional radiation technique, electromagnetic technique combine with computer, the a series of medical imaging diagnosis equipment that comprise CT, nuclear magnetic resonance etc. have been produced, changed medical science diagnosis and treatment idea and method, the medical image diagnosis and therapy system that grows up has on this basis become three big diagnosis and therapy systems with internal medicine diagnosis and therapy system, surgery diagnosis and therapy system contemporary medical science arranged side by side.Though the medical imaging diagnosis technology has obtained significant progress, also far can not satisfy the demand of actual clinical medical science.
Present clinical medical imaging technology can be divided into two big classes: (1) anatomical structure imaging technique belongs to second filial generation imaging technique.With CT, ultrasonic imaging technique, and utilize the MRI technology of nmr phenomena to be representative.But there is following drawback in this technology: have only when the disease generation, and formed organic disease, (as forming a certain size tumor) just can provide diagnostic result when the structure of linked groups and organ had changed, so be unsuitable for the early diagnosis of the disease of cancer and tumor.(2) functional imaging belongs to third generation imaging technique.Comprise single photon emission computerized tomography,SPECT (SPECT), positron emission emission computer scanning (PET) and Functional MRI (fMRI) and magneticencephalogram machine.Though the functional imaging technology of using can provide bio-tissue functional imaging result clearly at present.But the patient detects required expense height, and equipment is huge, can not accomplish the bedside real-time monitoring, to the timely judgement of change of illness state and therapeutic scheme adjust in real time help limited.And the employing ray, there is certain injury in nucleic to human body.So be badly in need of a kind of cheapness clinically, functional imaging technology portable and real-time monitoring continuously.
For satisfying above-mentioned clinical demand, people proposed the electrical impedance imaging technology (ElectricalImpedance Tomography, EIT).The electrical impedance imaging technology is utilized the electrical characteristic parameter distributed intelligence (such as the distribution of conductivity situation) in the bio-tissue, carry out functional imaging, yet there is following point in traditional electrode injection current formula electrical impedance imaging technology:
(1) error that causes of electrode epidermis contact impedance has had a strong impact on certainty of measurement.
(2) electric current directivity difference causes image resolution low.
When (3) being applied in the head imaging, the high resistivity of skull makes injection current that bigger decay be arranged, and has a strong impact on imaging effect.
Be to solve the problems referred to above of electrical impedance imaging, research in recent years begin to turn to non-contact magnetic inductive electrical impedance imaging technology (Magnetic Induction Tomography, MIT).Its basic thought is: change the form of extrinsic motivated field, the electrode injection current formation electric field with electrical impedance imaging changes contactless coil into and applies magnetic field.Can solve the error that electrode-the contact skin impedance causes like this.Simultaneously, unaffected because the skull of high resistivity can be passed through in magnetic field, so magnetic induction image is specially adapted to the header functionality imaging.The principle of magnetic induction electrical impedance imaging is: feed alternating current to excitation coil, alternating current produces alternating magnetic field.Alternating magnetic field is inductive loop in tested bio-tissue, and this eddy current field will produce extremely weak secondary magnetic field at the measured object surrounding space, and it is strong and weak directly related with the distribution of electrical conductivity in the bio-tissue.So,,, just can derive the distribution situation of electrical conductivity in the bio-tissue again according to the electromagnetic relationship of vortex density and electrical conductivity as long as measure spatial secondary magnetic field.
Present magnetic induction image technology (MIT) all adopts enclosed construction as shown in Figure 1, and this structure adopts 16 coils (or more) equally spaced around measured object, some coil stimulatings, and all the other coils are measured, so cycle detection.This enclosed structure has influenced imaging results owing to have coupling capacitance between excitation coil and the magnetic test coil.So the measuring system precision that this structure exists is not high.The undesirable deficiency that waits of imaging effect.And, be unfavorable for clinical use because testee is positioned in the middle of the coil.
Summary of the invention
For satisfying clinical medicine to small-sized, and the cheap generaI investigation noinvasive device for fast detecting and the needs of real-time monitoring functional imaging equipment, the purpose of this invention is to provide a kind of high-precision open type magnetic induction image measuring device.Can realize real-time functional imaging fast.
The technical scheme that adopts is so for achieving the above object: promptly a kind of high-precision magnetic induction image measuring device, comprise: controller 8, Direct Digital synthesized source A1, signal conditioning circuit B1, signal amplitude regulating circuit C1, Direct Digital synthesized source A2, signal conditioning circuit B2, signal amplitude regulating circuit C2, power amplification circuit 1, relay array 2, coil pickoff array 6, differential amplifier circuit array 7, switch arrays 3, signal conditioning circuit 4, difference amplifies 5, signal conditioning circuit B3, signal amplitude regulating circuit C3, the A/D change-over circuit, the coil temperature drift suppresses circuit 9, external communication interface 10 is characterized in that:
1). constitute the pumping signal passage by signal conditioning circuit A1, signal amplitude regulating circuit B1 and Direct Digital synthesized source C1, wherein Direct Digital synthesized source A1 produces frequency by the synthetic mode of Direct Digital, the sine wave signal that phase place is adjustable provides the pumping signal source for the excitation coil in the coil pickoff array 6; Signal amplitude regulating circuit B1 carries out low pass and high-pass filtering processing to the sine wave signal of signal conditioning circuit A1 output, for late-class circuit provides clean sine wave signal; Signal amplitude regulating circuit C1 can receive the control signal of self-controller, regulates the amplitude of input sine wave, realizes the adjusting of excitation signal strength;
2). constitute the offseting signal passage by Direct Digital synthesized source A2, signal conditioning circuit B2 and signal amplitude regulating circuit C2, wherein Direct Digital synthesized source A2 produces frequency by the synthetic mode of Direct Digital, the sine wave signal that phase place is adjustable, signal conditioning circuit B2 carries out low pass and high-pass filtering processing to the sine wave signal of Direct Digital synthesized source A2 output, for late-class circuit provides clean sine wave signal, signal amplitude regulating circuit C2 can receive the control signal of self-controller, regulates the amplitude of input sine wave;
3). the output signal of 1 pair of signal amplitude regulating circuit of power amplification circuit C1 is carried out power amplification, makes the excitation coil of output signal in can the actuating coil sensor array, and simultaneously, power amplification circuit also provides phase-locked amplification detection synchronizing signal to controller;
4). relay array receives the control signal of self-controller, and from several excitation coils, the current excitation coil of gating is received current excitation coil passage with the output signal of power amplification circuit 1;
5). the coil pickoff array is made up of 1～32 differential generator unit, each differential generator unit by a pair of be magnetic test coil L2 and L3, constitute with an excitation coil L1, magnetic test coil lays respectively at the both sides of excitation coil L3, the relative short circuit of the end of the same name of two magnetic test coils connects, and draws output signal line by non-same polarity;
6). the unitary magnetic test coil output of each differential generator all is connected to differential amplifier circuit, carries out difference and amplifies;
7). switch arrays 3 receive the control signal of self-controller 8, and from the magnetic test coil differential amplifier circuit, gating is worked as prepass, and the analogue signal that will work as prepass is sent to subordinate's signal conditioning circuit 4.
8). 4 pairs of input signals from switch arrays of signal conditioning circuit carry out low pass and high pass is handled, and carry out necessary gain and amplify;
9). difference is amplified 5 detection signals that the offseting signal and the signal conditioning circuit 4 of signal amplitude regulating circuit C2 output are exported and is carried out subtraction, obtains relative variable signal, is sent to subordinate's circuit; The signal that signal conditioning circuit B3 amplifies 5 outputs to difference carries out low pass and high-pass filtering processing, for back grade signal amplitude regulating circuit A3 provides clean signal, signal amplitude regulating circuit A3 is made of the amplifier of Gain Adjustable, can receive the control signal of self-controller, the analogue signal of the output signal of prime being carried out its output of gain-adjusted is sent to controller after the A/D change-over circuit is converted to digital signal;
10). coil temperature drift suppresses the resistance changes that circuit 9 detects excitation coils in real time, and the resistance change of excitation coil as feedback, is regulated the output amplitude of pumping signal, makes the excitation main magnetic field distribution be in plateau all the time;
11). controller 8
A1 transmits control signal to the Direct Digital synthesized source, makes the signal source outputting standard sine wave, changes the output signal frequency of Direct Digital synthesized source A1 by control signal;
C1 transmits control signal to the signal amplitude regulating circuit, changes the amplitude of input signal;
A2 transmits control signal to the Direct Digital synthesized source, makes the signal source outputting standard sine wave, changes the output signal frequency of Direct Digital synthesized source A2 by control signal;
C2 transmits control signal to the signal amplitude regulating circuit, changes the amplitude of input signal;
Transmit control signal the corresponding excitation coil of control relay switching gate to relay array;
Transmit control signal gauge tap array gating differential amplifier circuit array 7 corresponding output signal passages to switch arrays;
The phase-locked amplification detection synchronizing signal that reception is sent by power amplification circuit 1;
Receive the digital signal after the A/D change-over circuit is changed;
Receiving coil temperature drift suppresses the real-time temperature of coil of circuit transmission and floats signal, and measurement result is carried out temperature drift compensation;
Send measurement data to external communication interface 10, realize communication with other equipment;
Detection signal is realized the genlock algorithm process.
When above-mentioned coil pickoff array 6 of the present invention was made up of several differential generator unit, the differential generator unit is open single array or open matrix array passes arrangement formation detection probe.
The good effect that the present invention produces owing to said structure is very significant: the high-precision open type magnetic induction image device that this patent provides.It is measured referring to sketch map 2a, b, and open MIT structure is compared with closed MIT system structure, and maximum difference is that latter's excitation field passes through whole tested zone, and excitation and magnetic test coil are around one week of measured object, and the border is " sealing ".By filter back-projection algorithm, realize the image reconstruction of universe, be the universe imaging.And open MIT can regard as and is similar to ultrasonic device, and a detecting sensor probe below institute carries out imaging to the zone, and the border is open to the outside world.Become just certain limit under the reflection probe of image, the regional area of certain depth can be called local imaging.Local imaging wants simple with respect to the algorithm of universe imaging, and iterations reduces greatly, is easy to realize.Key is that the magnetic focusing performance of local imaging is good, and imaging effect is better than the universe imaging.Open MIT can realize the metering system of scan-type, greatly facilitates doctor's clinical use.Local imaging simultaneously is also low than universe imaging to the requirement of hardware system, and promptly the parameters such as port number of pumping signal reduce greatly.
Description of drawings
Said structure of the present invention can further specify by the embodiment that accompanying drawing provides:
Fig. 1 is a closed magnetic induction image system schematic of the prior art;
Fig. 2 is an open type magnetic induction image systematic survey sketch map, wherein: (a) open sensor array MIT system of open single pick off MIT system (b);
Fig. 3 is a structural representation of the present invention;
Fig. 4 is a work basic flow sheet of the present invention;
Fig. 5 is controller circuitry figure;
Fig. 6 is a Direct Digital synthesized source circuit diagram;
Fig. 7 is a signal conditioning circuit;
Fig. 8 is the signal amplitude regulating circuit;
Fig. 9 is a power amplification circuit;
Figure 10 is the relay array circuit diagram;
Figure 11 is the unitary structural representation of differential generator;
Figure 12 is the sensor unit pictorial diagram;
Figure 13 is a differential amplifier circuit;
Figure 14 is switch arrays;
Figure 15 is a signal amplitude regulating circuit 3;
Figure 16 suppresses circuit for the coil temperature drift;
Figure 17 is the A/D change-over circuit.
The specific embodiment
Referring to accompanying drawing 3, high-precision magnetic induction image measuring device provided by the invention, comprise: controller 8, Direct Digital synthesized source A1, signal conditioning circuit B1, signal amplitude regulating circuit C1, Direct Digital synthesized source A2, signal conditioning circuit B2, signal amplitude regulating circuit C2, power amplification circuit 1, relay array 2, coil pickoff array 6, differential amplifier circuit array 7, switch arrays 3, signal conditioning circuit 4, difference amplifies 5, signal conditioning circuit B3, signal amplitude regulating circuit C3, the A/D change-over circuit, the coil temperature drift suppresses circuit 9, external communication interface 10 is characterized in that:
1). constitute the pumping signal passage by signal conditioning circuit A1, signal amplitude regulating circuit B1 and Direct Digital synthesized source C1, wherein Direct Digital synthesized source A1 produces frequency by the synthetic mode of Direct Digital, the sine wave signal that phase place is adjustable provides the pumping signal source to the excitation coil in the coil pickoff display; Signal amplitude regulating circuit B1 carries out low pass and high-pass filtering processing to the sine wave signal of signal conditioning circuit A1 output, for late-class circuit provides clean sine wave signal; Signal amplitude regulating circuit C1 can receive the control signal of self-controller, regulates the amplitude of input sine wave, realizes the adjusting of excitation signal strength;
2). constitute the offseting signal passage by Direct Digital synthesized source A2, signal conditioning circuit B2 and signal amplitude regulating circuit C2, wherein Direct Digital synthesized source A2 produces frequency by the synthetic mode of Direct Digital, the sine wave signal that phase place is adjustable, signal conditioning circuit B2 carries out low pass and high-pass filtering processing to the sine wave signal of Direct Digital synthesized source A2 output, for late-class circuit provides clean sine wave signal, signal amplitude regulating circuit C2 can receive the control signal of self-controller, regulates the amplitude of input sine wave;
3). the output signal of 1 pair of signal amplitude regulating circuit of power amplification circuit C1 is carried out power amplification, makes the excitation coil of output signal in can the actuating coil sensor array, and simultaneously, power amplification circuit also provides phase-locked amplification detection synchronizing signal to controller;
4). relay array receives the control signal of self-controller, and from several excitation coils, the current excitation coil of gating is received current excitation coil passage with the output signal of power amplification circuit 1;
5). coil pickoff array (6) is made up of 1～32 differential generator unit, each differential generator unit by a pair of be magnetic test coil L2 and L3, constitute with an excitation coil L1, magnetic test coil lays respectively at the both sides of excitation coil L3, the relative short circuit of the end of the same name of two magnetic test coils connects, and draws output signal line by non-same polarity;
6). the unitary magnetic test coil output of each differential generator whenever all is connected to differential amplifier circuit, carries out difference and amplifies;
7). switch arrays 3 receive the control signal of self-controller 8, and from the magnetic test coil differential amplifier circuit, gating is worked as prepass, and the analogue signal that will work as prepass is sent to subordinate's signal conditioning circuit 4.
8). 4 pairs of input signals from switch arrays of signal conditioning circuit carry out low pass and high pass is handled, and carry out necessary gain and amplify;
9). difference is amplified 5 detection signals that the offseting signal and the signal conditioning circuit 4 of signal amplitude regulating circuit C2 output are exported and is carried out subtraction, obtains relative variable signal, is sent to subordinate's circuit; The signal that signal conditioning circuit B3 amplifies 5 outputs to difference carries out low pass and high-pass filtering processing, for back grade signal amplitude regulating circuit A3 provides clean signal, signal amplitude regulating circuit A3 is made of the amplifier of Gain Adjustable, can receive the control signal of self-controller, the analogue signal of the output signal of prime being carried out its output of gain-adjusted is sent to controller after the A/D change-over circuit is converted to digital signal;
10). coil temperature drift suppresses the resistance changes that circuit 9 detects excitation coils in real time, and the resistance change of excitation coil as feedback, is regulated the output amplitude of pumping signal, makes the excitation main magnetic field distribution be in plateau all the time;
11). controller 8
A1 transmits control signal to the Direct Digital synthesized source, makes the signal source outputting standard sine wave, changes the output signal frequency of Direct Digital synthesized source A1 by control signal;
C1 transmits control signal to the signal amplitude regulating circuit, changes the amplitude of input signal;
A2 transmits control signal to the Direct Digital synthesized source, makes the signal source outputting standard sine wave, changes the output signal frequency of Direct Digital synthesized source A2 by control signal;
C2 transmits control signal to the signal amplitude regulating circuit, changes the amplitude of input signal;
Transmit control signal the corresponding excitation coil of control relay switching gate to relay array;
Transmit control signal gauge tap array gating differential amplifier circuit array 7 corresponding output signal passages to switch arrays;
The phase-locked amplification detection synchronizing signal that reception is sent by power amplification circuit 1;
Receive the digital signal after the A/D change-over circuit is changed;
Receiving coil temperature drift suppresses the real-time temperature of coil of circuit transmission and floats signal, and measurement result is carried out temperature drift compensation;
Send measurement data to external communication interface 10, realize communication with other equipment;
Detection signal is realized the genlock algorithm process.The genlock algorithm is a kind of known small-signal extracting method.This method adopts and the reference signal B of detected signal A same frequency multiply by detected signal A, detect DC component with low pass filter, will obtain so and the proportional DC voltage of input signal amplitude, and with the different composition of signal A frequency, promptly the noise frequency composition then all is to exchange to be low pass filtering the device filtering.
It is the processor of the ARM kernel of LPC2148 that controller 8 in the embodiment of the invention can adopt commercially available model as shown in Figure 5.
The Direct Digital synthesized source A1 that adopts in the embodiment of the invention is made of the Direct Digital synthesis chip AD9833 of U.S. ADI company.By the control of controller LPC2148, realize the phase place of signal source output sinusoidal signal, frequency adjustment.Physical circuit is seen Fig. 6.
The signal conditioning circuit B1 that adopts in the embodiment of the invention is the second-order low-pass filter that commercially available operational amplifier OPA2350 constitutes.Signal conditioning circuit 1 is seen Fig. 7.
The signal amplitude regulating circuit C1 that adopts in the embodiment of the invention is that the digital regulation resistance chip MAX5400 and the operational amplifier OPA2350 of commercially available Maxim company constitutes, and by the control of controller LPC2148, realizes that the amplitude of input sinusoidal signal is regulated.Physical circuit is seen Fig. 8.
The Direct Digital synthesized source A2 that adopts in the embodiment of the invention is with Direct Digital synthesized source A1.
The signal conditioning circuit B2 that adopts in the embodiment of the invention is with signal amplitude regulating circuit B1.
The signal amplitude regulating circuit C2 that adopts in the embodiment of the invention is with signal amplitude regulating circuit C1.
The power amplification circuit 1 that adopts in the embodiment of the invention is made of the power amplifier OPA548 of commercially available American TI Company.Power amplification circuit is seen Fig. 9.
The relay array that adopts in the embodiment of the invention is made of the solid-state relay PS710B of 4 Japanese NEC Corporations.Physical circuit is seen Figure 10.Figure 10 is that the small-sized measuring system relay array with 4 probes is an example, and the present invention can extend to 32 probe systems, and number of switches need be done corresponding increase on the basis of 4 probe systems.
The coil pickoff array that adopts in the embodiment of the invention is made of 4 sensor unit parallel connections.Each sensor unit structure is seen Figure 11.Differential generator unit among the figure is made of printed circuit board (PCB) (PCB) coil of the parallel installation of three concentricity axles.Excitation coil L1 is positioned at the centre position of coaxial configuration.Magnetic test coil is made of L2 and L3, and L2 and L3 lay respectively at the both sides of excitation coil, and the relative short circuit of end of the same name of L2 and L3 is connected, and draws output signal line by non-same polarity.L1 among the figure, L2, L3 all are printed circuit board (PCB) (PCB) coils.
The differential amplifier circuit array 7 that adopts in the embodiment of the invention is for to be made of 4 differential amplifier circuits.Differential amplifier circuit adopts the operational amplifier OPA2350 of American TI Company to build.Circuit is seen Figure 13.
The switch arrays 3 that adopt in the embodiment of the invention are made of the analog switch chip MAX306 of Maxim company, and physical circuit is seen Figure 14
The signal conditioning circuit 4 that adopts in the embodiment of the invention adopts with the identical circuit of signal conditioning circuit A1.
The difference that adopts in the embodiment of the invention is amplified 5 and is adopted the operational amplifier OPA2350 of American TI Company to build, and circuit is seen Figure 13.
The signal conditioning circuit B3 that adopts in the embodiment of the invention is identical with signal conditioning circuit B1.
The signal amplitude regulating circuit A3 that adopts in the embodiment of the invention is the amplifier of Gain Adjustable, adopts the MCP6S21 chip of U.S. Microchip company to make up.Circuit is seen Figure 15
The coil temperature drift of adopting in the embodiment of the invention suppresses circuit 9 and adopts the IN133 chip of American TI Company to build.Detect the resistance variations of current excitation coil in real time.Circuit is seen Figure 16.
The A/D change-over circuit that adopts in the embodiment of the invention is made of the chip AD9220 and the control chip EP2C8 of U.S. ADI company, and circuit is seen Figure 17.
The external communication interface 10 that adopts in the embodiment of the invention is RS232 serial mode or usb mode.
The invention provides a kind of adding under the magnetic field excitation, high precision measuring device that can the faint secondary induced field of detection of biological soma.Key technology comprises following 3 points:
(1) differential generator unit
Its structure chart is as above shown in Figure 11.The characteristics of this structure are the influences that two magnetic test coils can be offset master drive magnetic field preferably.Magnetic test coil and excitation coil all adopt printed circuit board technology to make, and have guaranteed the stability of coil dimension, and the symmetry of two magnetic test coils.
(2) initialization digital zero setting technology
Though the differential generator cellular construction can be offset most of master drive magnetic field, but can not accomplish to offset fully, under sensor probe during no measured object, after the magnetic test coil output signal is amplified through difference, it is the output signal of 2-3V that peak-to-peak value is still arranged, and this signal has influenced the sensitivity of measuring system greatly.
In view of above-mentioned phenomenon, the present invention proposes initialization digital zero setting technology.Its basic thought is: before this device measuring, advanced line output signal initialization digital zero setting is handled, and makes output signal very little or almost nil, and later measurement is just carried out on this zeroing basis.This needs one road offseting signal is provided on hardware designs, is used for subtracting each other with the output of Fig. 3 signal conditioning circuit 4.Direct Digital synthesized source A2 among Fig. 3, signal conditioning circuit B2 and signal amplitude regulating circuit C2 constitute the offseting signal passage.Controller sends digital signal to Direct Digital synthesized source A2 and signal amplitude regulating circuit C2, regulate the phase place and the amplitude of offseting signal, produce and the offseting signal of signal conditioning circuit 4 same frequency same phases with amplitude, send into difference amplification 5 with the output signal of signal conditioning circuit 4 and subtract each other, realize the initialization digital zero setting.Simultaneously, when the initialization digital zero setting was handled, difference was amplified 5 output through signal conditioning circuit B3, signal amplitude regulating circuit C3, and A/D change-over circuit send into controller, realize the detection of initialization digital zero setting effect, thereby make initialization digital zero setting effect reach best.
(3) temperature drift suppresses technology
During the detection system long-term work, there is drift slowly in its output voltage signal, can long-term stable operation for making system, and this patent adopts temperature drift to suppress technology.Excitation coil long-term work heating and surrounding air irregular convection change the equivalent series resistance parameter of excitation coil, and this is the main cause that causes signal drift.This patent adopts the coil resistance real-time detection circuit, measures the resistance change of excitation coil in real time, and with it as feedback, regulate the amplitude of pumping signal, make the excitation main magnetic field distribution be in plateau all the time.
Work basic procedure of the present invention:
The workflow of this Signal Measurement System comprises 2 stages: initial phase and formal measuring phases, and with flowcharting such as Fig. 5.
Initial phase is suspended in sensor array in the air, and any object is not placed in the pick off below.Sensor unit in the sensor array is carried out the initialization digital zero setting one by one, when adjusting zero effect reaches the best, note signal phase value of setting of Direct Digital synthesized source A2 this moment, and amplitude value of setting of signal amplitude regulating circuit C2.The corresponding one group of phase place value of setting of each sensor unit and the amplitude value of setting.When formal the measurement, corresponding the phase place value of setting and the amplitude value of setting will be called.
During formal the measurement, classify example as, introduce the formal flow process of measuring with the sensor array that n sensor unit formed.The formal measurement comprises n multiple measuring process.Excitation coil in the sensor array is connected successively, and each has only an excitation coil in running order constantly, other excitation coils open circuit, but magnetic test coil output detection signal successively.Suppose that when the excitation coil in i the sensor unit was connected, since the magnetic test coil of the 1st sensor unit, cycle detection was measured n time up to n magnetic test coil, finishes the measurement of i sensor unit, obtains n measurement data.Switch to i+1 excitation coil then, carry out next round and detect.So circulation is n time, finishes the n wheel measurement, obtains n*n data.
Claims (3)
1, a kind of highly sensitive open type magnetic induction image measuring device, comprise: controller (8), the first Direct Digital synthesized source (A1), first signal conditioning circuit (B1), the first signal amplitude regulating circuit (C1), the second Direct Digital synthesized source (A2), secondary signal modulate circuit (B2), secondary signal amplitude regulating circuit (C2), power amplification circuit (1), relay array (2), coil pickoff array (6), differential amplifier circuit array (7), switch arrays (3), the 4th signal conditioning circuit (4), differential amplifier circuit (5), the 3rd signal conditioning circuit (B3), the 3rd signal amplitude regulating circuit (C3), A/D change-over circuit (11), the coil temperature drift suppresses circuit (9), external communication interface (10) is characterized in that:
1). constitute the pumping signal passage by the first Direct Digital synthesized source (A1), first signal conditioning circuit (B1) and the first signal amplitude regulating circuit (C1), wherein the first Direct Digital synthesized source (A1) produces frequency, sine wave signal that phase place is adjustable by the synthetic mode of Direct Digital, the pumping signal source is provided for the excitation coil in the coil pickoff array; First signal conditioning circuit (B1) carries out low pass and high-pass filtering processing to the sine wave signal of the first Direct Digital synthesized source (A1) output, for late-class circuit provides clean sine wave signal; The first signal amplitude regulating circuit (C1) receives the control signal of self-controller (8), regulates the amplitude of input sine wave, realizes the adjusting of excitation signal strength;
2). by the second Direct Digital synthesized source (A2), secondary signal modulate circuit (B2) and secondary signal amplitude regulating circuit (C2) constitute the offseting signal passage, wherein the second Direct Digital synthesized source (A2) produces frequency by the synthetic mode of Direct Digital, the sine wave signal that phase place is adjustable, secondary signal modulate circuit (B2) carries out low pass and high-pass filtering processing to the sine wave signal of the second Direct Digital synthesized source (A2) output, for late-class circuit provides clean sine wave signal, secondary signal amplitude regulating circuit (C2) receives the control signal of self-controller (8), regulates the amplitude of input sine wave;
3). power amplification circuit (1) carries out power amplification to the output signal of the first signal amplitude regulating circuit (C1), make the excitation coil of output signal in can actuating coil sensor array (6), simultaneously, power amplification circuit (1) also provides phase-locked amplification detection synchronizing signal to controller (8);
4). relay array (2) receives the control signal of self-controller (8), and from coil pickoff array (6), the current excitation coil of gating is received current excitation coil passage with the output signal of power amplification circuit (1);
5). coil pickoff array (6) is made up of the differential generator unit, from 1 to 32 of element number is adjustable, every group of differential generator unit is by a pair of magnetic test coil (L2, L3) and an excitation coil (L1) constitute, magnetic test coil lays respectively at the both sides of excitation coil (L1), the relative short circuit of the end of the same name of two magnetic test coils connects, and draws output signal line by non-same polarity;
6). differential amplifier circuit array (7) is made of differential amplifier circuit, and the quantity of differential amplifier circuit is identical with differential generator unit number in the coil pickoff array (6); The differential input end of differential amplifier circuit is connected with the output signal line of respective differences dynamic formula sensor unit;
7). switch arrays (3) receive the control signal of self-controller (8), and from differential amplifier circuit array (7), gating is worked as prepass, and the analogue signal that will work as prepass is sent to the 4th signal conditioning circuit (4);
8). the input signal from switch arrays (3) is carried out low pass to the 4th signal conditioning circuit (4) and high pass is handled, and carry out necessary gain and amplify;
9). differential amplifier circuit (5) carries out subtraction with the offseting signal of secondary signal amplitude regulating circuit (C2) output and the detection signal of the 4th signal conditioning circuit (4) output, obtains relative variable signal, is sent to the 3rd signal conditioning circuit (B3); The 3rd signal conditioning circuit (B3) carries out low pass and high-pass filtering processing to the signal of differential amplifier circuit (5) output, is that the 3rd signal amplitude regulating circuit (C3) provides clean signal; The 3rd signal amplitude regulating circuit (C3) is made of the amplifier of Gain Adjustable, can receive the control signal of self-controller (8), and the output signal of the 3rd signal conditioning circuit (B3) is carried out gain-adjusted; The analogue signal of the 3rd signal amplitude regulating circuit (C3) output is sent to controller (8) after A/D change-over circuit (11) is converted to digital signal;
10). the coil temperature drift suppresses the resistance change that circuit (9) detects excitation coil in real time, and the resistance change of excitation coil is sent into controller (8) as feedback signal;
11). controller (8)
Transmit control signal to the first Direct Digital synthesized source (A1), make first Direct Digital synthesized source (A1) outputting standard sine wave, change first Direct Digital synthesized source (A1) output signal frequency by control signal;
Transmit control signal to the first signal amplitude regulating circuit (C1), regulate the amplitude of first signal conditioning circuit (B1) output signal by the gain that changes the first signal amplitude regulating circuit (C1);
Transmit control signal to the second Direct Digital synthesized source (A2), make second Direct Digital synthesized source (A2) outputting standard sine wave, change second Direct Digital synthesized source (A2) output signal frequency and the phase place by control signal;
Transmit control signal to secondary signal amplitude regulating circuit (C2), regulate the amplitude of secondary signal modulate circuit (B2) output signal by the gain that changes secondary signal amplitude regulating circuit (C2);
Transmit control signal the corresponding excitation coil of control relay switching gate to relay array (2);
Transmit control signal the output signal channel of the corresponding differential amplifier circuit of gauge tap array gating differential amplifier circuit array (7) to switch arrays (3);
The phase-locked amplification detection synchronizing signal that reception is sent by power amplification circuit (1);
Receive the digital signal after A/D change-over circuit (11) is changed;
Receiving coil temperature drift suppresses the real-time temperature of coil of circuit (9) transmission and floats signal, and measurement result is carried out temperature-compensating;
Send measurement data to external communication interface (11), realize communication with other equipment;
Detection signal is realized the genlock algorithm process.
2, highly sensitive open type magnetic induction image measuring device according to claim 1, it is characterized in that: coil pickoff array (6) is made up of the differential generator unit, from 1 to 32 of element number is adjustable, and the differential generator unit is open single array or open matrix array is arranged the formation detection probe.
3, highly sensitive open type magnetic induction image measuring device according to claim 1 and 2, it is characterized in that: each differential generator unit is made of the printed circuit board coil of the parallel installation of three concentricity axles, excitation coil (L1) is arranged in concentricity axle construction two magnetic test coils (L2, centre position L3).
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| CNB200710092746XA CN100484468C (en) | 2007-09-25 | 2007-09-25 | High sensitivity open type magnetic induction image measuring device |
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| JP2012513811A (en) * | 2008-12-30 | 2012-06-21 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Magnetic induction tomography |
| RU2534858C2 (en) * | 2009-03-30 | 2014-12-10 | Конинклейке Филипс Электроникс Н.В. | Magnetic induction tomography systems of coil configuration |
| CN102499682B (en) * | 2011-10-19 | 2013-08-07 | 中国人民解放军第四军医大学 | Excitation measuring multiplexing coil assembly for magnetic induction tomography and data collection |
| CN103376435B (en) * | 2012-04-28 | 2015-09-30 | 上海联影医疗科技有限公司 | Coil measurement device and Coil Detector method thereof |
| DE102012216007A1 (en) * | 2012-09-10 | 2014-03-13 | Siemens Aktiengesellschaft | MR patient table with integrated RF facilities (RF PA) |
| CN103006185B (en) * | 2012-12-19 | 2015-06-17 | 中国人民解放军第四军医大学 | Device and method for non-contact magnetic induction impedance plane projection imaging |
| CN103344835B (en) * | 2013-07-02 | 2015-04-22 | 富勇 | Magnetic induction measuring method |
| CN104970793B (en) * | 2015-06-27 | 2018-06-12 | 杭州永川科技有限公司 | A kind of magnetic induction electrical impedance imaging device and method of space physics comparison frame |
| CN107753019A (en) * | 2017-10-20 | 2018-03-06 | 北京润脉科技有限公司 | Bio-electrical impedance measuring apparatus and measuring method |
| CN108992068A (en) * | 2018-08-10 | 2018-12-14 | 京东方科技集团股份有限公司 | A kind of phase compensating circuit, magnetic induction image device and phase compensating method |
| CN110108790B (en) * | 2019-06-20 | 2022-11-08 | 中国矿业大学 | Detection method of in-service pulse eddy current detection device for damage of mining hoisting steel wire rope |
| CN114176555B (en) * | 2021-12-31 | 2024-09-03 | 厦门大学 | Magnetic induction imaging signal acquisition device based on maximum offset principle |
| CN117942058B (en) * | 2024-03-27 | 2024-06-11 | 华中科技大学同济医学院附属协和医院 | Electromagnetic positioning method and system combining direct current and alternating current magnetic signals |
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