Medium inner conduit positioning circuit based on photon detection sensor and positioning method thereof

Abstract

The invention discloses a medium inner conduit positioning circuit based on a photon detection sensor and a positioning method of the medium inner conduit positioning circuit, and relates to positioning of an in-vivo interventional conduit in medical equipment and a complex structure in industry and construction, and the technical scheme is characterized in that geometric parameters of a positioned area are acquired, and a space model of an effective positioning area is established; s2, acquiring parameters of a photoelectric detector and a gamma ray emission device group, and calculating the position, power and angle of the gamma ray emission device group according to the effective positioning area in S1; acquiring gamma ray transmitting and receiving time difference, calculating the distance between the transmitting module and the sensor, and further calculating the position information of the sensor by using a three-ball positioning principle; based on the positioning scheme of S3, a time-to-digital converter (TDC) is designed, the time measurement precision is improved, and the precision of the positioning system is further improved. According to the invention, high-precision sensor positioning is realized by using a three-ball positioning method by accurately measuring the transmitting and receiving time difference of gamma rays.

Description

Technical Field

[0001] The present invention relates to positioning of in vivo interventional catheters in medical equipment and complex structures in industry and construction, and more specifically, to a catheter positioning circuit and a positioning method in a medium based on a photon detection sensor. Background Art

[0002] Gamma rays are electromagnetic photons with extremely short wavelengths and strong penetrability. They are widely used in the fields of medical radiation and industrial detection. Photon detectors can detect weak light signals and convert them into electrical signal outputs. High-sensitivity photon detectors can detect single photon signals.

[0003] In the prior art, detectors are usually used to locate gamma-ray radiation sources, which are widely used in environmental assessment and safety fields. By discretely processing the detection area, a measurement model of the detector in space is established, and finally the detector measurement values ​​are processed to determine the radiation source position information. However, in the medical field, the emission source is inside the body, and sensors outside the body detect the rays to obtain the position. Radiation from the radiation source inside the body can cause great harm to the human body, which will also limit its use in the field of industrial flaw detection.

[0004] Therefore, new solutions need to be proposed to solve this problem. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a positioning method based on a photon detection sensor, comprising the following steps:

[0006] S1: Obtain the geometric parameters of the area to be determined and establish a spatial model of the effective positioning area;

[0007] S2: Obtaining parameters of the photoelectric detector and the gamma-ray emitting device group, and calculating the position, power and angle of the gamma-ray emitting device group according to the effective positioning area described in S1;

[0008] S3: Collect the time difference between gamma ray emission and reception, calculate the distance between the transmitting module and the sensor, and further calculate the sensor position information using the three-ball positioning principle;

[0009] S4: Based on the positioning scheme of S3, a time-to-digital converter (TDC) is designed to improve the time measurement accuracy and further improve the accuracy of the positioning system.

[0010] Further, a spatial origin and a basic plane (XY plane) are determined in S1, and an effective positioning area is set according to the actual area to be positioned, the effective positioning area simultaneously includes the actual positioning area and a cube area with a 10% margin, the actual positioning area and the cube area have the same geometric center, one vertex of the cube is the origin, the side length of the cube is L, and the vertex coordinates are the origin (X0, Y0, Z0), (L, 0, 0), (0, L, 0), (0, 0, L), (L, L, 0), (L, 0, L), (0, L, L), (L, L, L); the method for setting the 10% margin is: determine the geometric center of the actual positioning area, and construct a cuboid with a maximum side length of l that is tangent to the actual positioned area with the geometric center, L = 1.2l, so the distance between the cube and the long boundary surface is 0.1l.

[0011] Furthermore, in S2, the position of the gamma-ray emission module is calculated according to the effective positioning area of ​​the cube, and a spatial calculation model of the gamma-ray emission device group is established, and the calculation basis is as follows:

[0012] First of all, the formula for calculating gamma ray energy is based on electromagnetic wave theory, and the formula for ray energy is:

[0013] E=h*f*(1-e -αr )

[0014] Where E is the energy of the gamma ray, which is related to the transmitter power, h is Planck's constant, f is the frequency of the gamma ray, α is the attenuation coefficient of the gamma ray, and r is the distance the gamma ray propagates. That is, when the transmitter module power is determined, the energy of the ray received in the area at a distance r from the transmitter module is fixed.

[0015] Secondly, the relevant formula for the photoelectric sensor is as follows:

[0016] i=KI

[0017]

[0018] Where i is the current generated by the photoelectric sensor, K is the photoelectric sensitivity of the photoelectric sensor, I is the light intensity, P is the power of light, and A is the surface area of ​​the sensor. The intensity of the gamma ray received by the sensor at a distance r from the transmitting module is proportional to its energy at that point, and the current generated is proportional to the light intensity. When the sensitivity of the sensor is fixed, its maximum distance from the gamma ray is fixed. According to the gamma ray transmitting module position confirmation method of claim 2, the specific position information of the gamma ray transmitting device group can be obtained;

[0019] Finally, the position of the gamma ray is defined as being between the center of the cube and (L, 0, L), (0, L, L),

[0020] The direction of the straight line determined by the three vertices (L, L, L) is the direction from the center point to the vertex. The emission angle of the gamma ray needs to meet certain conditions (greater than) to cover the effective positioning area. The calculation formula is as follows:

[0021]

[0022] Furthermore, the gamma-ray emitting device group includes at least three groups of gamma-ray emitting devices, and the gamma-ray emitting device is composed of a gamma-ray emitting module and a ray shielding module; the ray emitted by the emitting module is a conical area of ​​a certain angle, and the area should cover the effective positioning area; the ray shielding module is a lead plate, and closing the ray shielding module can prevent the rays emitted by the gamma-ray emitting module from reaching the effective positioning area, otherwise the rays can reach the effective positioning area.

[0023] Furthermore, the time difference of the photoelectric signal obtained by the located sensor in S3 can be used to calculate the distance between the located terminal and each transmitting module, and further obtain the precise position of the located terminal in the medium. The specific implementation scheme is as follows:

[0024] First, the gamma ray shielding module switch is controlled by a periodic signal, and the opening time t of the gamma ray shielding module is recorded. s1 With duration t s2 ; Then, by selecting the output channel of the periodic signal controlled by the circuit, the clock signal is controlled to be output to different ray shielding modules in turn, and three clock cycles constitute a measurement cycle; secondly, the integrated high-sensitivity photoelectric sensor module located in the measured area collects gamma rays and records the collection start time t r1 With duration t r2 ; Again, by calculating t s1 ,t r1 The time difference can be used to calculate the distance from the positioned end (sensor) to each gamma ray emission module; and the time difference T between the sensor receiving each emission module in the current measurement period is recorded. S The time difference T between the last measurement cycle and the last measurement cycle L , calculate the time difference between the two, and further calculate the distance change between the located terminal and each transmitting module. The calculation formula is as follows:

[0025] S=C×(t r1 -t s1 )

[0026] ΔS=C×(T S -T L )

[0027] Where S is the distance from the sensor to the corresponding gamma ray emission module, C is the speed of light, and is the distance the sensor moves in one positioning cycle. Finally, according to the photon detection sensor positioning method of claim 5, it is characterized in that the three-ball positioning method is used to solve the sensor position information, and the specific formula is as follows:

[0028]

[0029] where represents the distance from the sensor to the i-th gamma-ray emission module, (x i ,y i , z i ) represents the position coordinates of the i-th gamma-ray emission module, and (x, y, z) represents the sensor coordinates to be solved. However, the positioning system itself will have measurement errors, and the solution to the position solution equation may not exist. The least squares method is introduced during the solution to obtain an approximate solution to the solution equation group.

[0030] Furthermore, the following steps are included to improve the stability and positioning accuracy of the positioning system:

[0031] S3.1: First, fix the positioned end at a spatial point with known position information by calibrating the mechanical bracket, and enter the position information of the positioned end; secondly, control the gamma ray emission module to emit gamma rays, and obtain the time information described in claim 5 through the positioned end, and calculate the measurement value of the positioned end; then, repeat the above steps to obtain multi-point spatial information (measured value and actual value); finally, use the least squares method to obtain the calibration coefficient, and introduce the coefficient for correction when performing position solution.

[0032] Furthermore, in S4, a time-to-digital converter (TDC) is designed based on a field programmable logic device FPGA to achieve high-precision time interval measurement at a relatively low clock frequency.

[0033] A positioning device based on a photon detection sensor comprises an integrated high-sensitivity photoelectric sensor module, a gamma-ray emission component, a weak electric signal amplification and collection circuit, a signal processing circuit, a medium conduit, a calibration bracket, and a program and a memory for implementing a positioning method; the integrated high-sensitivity photoelectric sensor module is embedded in the head end of a medium conduit as a positioned terminal, and is used to collect gamma-ray energy and convert it into a current signal, and the electric signal is used as an input signal of a low-noise amplifier via a thin wire in the medium conduit, and is sampled by an ADC module after amplification; the wire has a diameter of 1 mm, and the cut-off conduit has a diameter of 10 mm; the medium conduit is hard-linked to the weak signal amplification and collection circuit, and can protect the wire from damage; the gamma-ray emission component consists of a gamma-ray emission module, a controllable ray shielding module, a motion mechanical arm, etc.

[0034] Furthermore, the positioning device realizes functions such as system control signal generation, data acquisition and processing, and time interval measurement based on FPGA. The positioning device includes a gamma ray emission control module, a robotic arm motion control module, a data acquisition module, a signal processing module, and a time measurement module.

[0035] In summary, the present invention has the following beneficial effects:

[0036] 1. High-precision positioning: By combining gamma rays and photoelectric sensors, the three-ball positioning method is used to accurately measure the time difference between the emission and reception of gamma rays. In particular, the design of the time-to-digital converter (TDC) greatly improves the time measurement accuracy, thereby further improving the positioning accuracy.

[0037] 2. High applicability: Compared with the traditional flaw detection system where both transmission and reception are outside the object, the sensor of this patent can enter the inside of the object and can enter the complex industrial structure to achieve internal positioning of complex industrial products.

[0038] 3. Low damage to human body: The switch of gamma ray shielding module is controlled by periodic signal to reduce unnecessary radiation emission, thereby reducing radiation exposure time and reducing harm to human body.

[0039] 4. System error correction: Through the system calibration step, the least square method is used to correct the measurement error to ensure the stability and accuracy of the positioning system in different environments. The positioning system in the existing technology may have large errors in measurement accuracy, and this technology effectively reduces the error by introducing an error calibration mechanism.

[0040] 5. Large coverage area: By setting the angle and power of the gamma-ray transmitter, it is possible to ensure full coverage of the effective positioning area, and the position and angle of the transmitter can be flexibly adjusted according to the application scenario, providing a larger positioning area and flexibility.

[0041] 6. Low noise, high sensitivity signal processing: The integrated high sensitivity photoelectric sensor module and weak signal amplification circuit design can effectively collect and amplify the signals generated by gamma rays, ensuring high measurement accuracy even in weak signal conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic diagram of a positioning device based on a photon detection sensor of the present invention;

[0043] Figure 2 A schematic diagram of the steps for implementing the present invention;

[0044] Figure 3 It is a schematic diagram of the space model of the present invention;

[0045] Figure 4 This is a schematic diagram of the position of the gamma-ray emission module of the present invention;

[0046] Figure 5 This is a schematic diagram of the gamma ray calculation angle of the present invention;

[0047] Figure 6 A schematic diagram of a vernier delay chain used in the present invention;

[0048] Figure 7 This is a schematic diagram of the three-ball positioning principle adopted by the present invention. DETAILED DESCRIPTION

[0049] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0050] Example: Figure 1 This is a schematic diagram of a positioning device based on a photon detection sensor according to an embodiment of the present disclosure, including an integrated high-sensitivity photoelectric sensor module (silicon photoelectric sensor, model S10355-01), a gamma-ray generating assembly (consisting of a gamma-ray emission module, a controllable ray shielding module, a motion mechanical arm, etc.), a weak electrical signal amplification and acquisition circuit, and a signal processing circuit. In addition, it also includes a medium conduit, a calibration bracket, and a program and memory for implementing a positioning method; the integrated high-sensitivity photoelectric sensor module is embedded in the head end of the medium as the terminal to be positioned, and is used to collect gamma-ray energy and convert it into a current signal. The electrical signal is used as an input signal of a low-noise amplifier via a thin wire in the medium conduit, and is sampled by an ADC module after amplification; the wire diameter is 1mm, and the cut-off conduit diameter is 10mm. The medium conduit is hard-linked to the weak signal amplification and acquisition circuit to protect the wire from damage;

[0051] Figure 2 This is a schematic diagram of the specific steps of the positioning method based on the photon detection sensor according to the embodiment of the present disclosure, which is divided into four steps, including:

[0052] Step 1: spatial modeling, solving the effective positioning area; determining a spatial origin and a basic plane (XY plane), and setting the effective positioning area according to the actual area to be determined, the effective area is a cube area that contains the actual located effective area and leaves a 10% margin, one vertex of the cube is the origin, the side length of the cube is L, and the vertex coordinates are the origin (X0, Y0, Z0), (L, 0, 0), (0, L, 0), (0, 0, L), (L, L, 0), (L, 0, L), (0, L, L), (L, L, L); the method for setting the 10% margin is: determining several centers of the actual located area, and constructing a cuboid (side length l) tangent to the actual located area with the several centers, and using the side length of 1.2 times the long side of the cuboid, i.e. L, to establish a cube, and the distance between the cube and the long boundary surface is 0.1l. Figure 3 It is a schematic diagram of the spatial model of the positioning method based on the photon detection sensor described in the embodiment of the present disclosure, wherein the irregular gray area is the actual positioned area, and the square is the calculated effective positioned area.

[0053] Step 2: Determine the position of the gamma-ray emission device group, i.e., the emission module parameters: Calculate the position of the gamma-ray emission module according to the effective positioning area of ​​the cube, and establish a spatial calculation model of the gamma-ray emission device group. The calculation basis is as follows:

[0054] First of all, the formula for calculating gamma ray energy is based on electromagnetic wave theory, and the formula for ray energy is:

[0055] E=h*f*(1-e -αr )

[0056] Where E is the energy of the gamma ray, which is related to the transmitter power, h is Planck's constant, f is the frequency of the gamma ray, α is the attenuation coefficient of the gamma ray, and r is the distance the gamma ray propagates. That is, when the transmitter module power is determined, the energy of the ray received in the area at a distance r from the transmitter module is fixed.

[0057] Secondly, the relevant formula for the photoelectric sensor is as follows:

[0058] i=KI

[0059]

[0060] Where i is the current generated by the photoelectric sensor, K is the photoelectric sensitivity of the photoelectric sensor, I is the light intensity, P is the power of light, and A is the surface area of ​​the sensor. The intensity of the gamma ray received by the sensor at a distance r from the transmitting module is proportional to its energy at that point, and the current generated is proportional to the light intensity. When the sensitivity of the sensor is fixed, its maximum distance from the gamma ray is fixed, and the specific position information of the gamma ray transmitting device group can be obtained according to the method for confirming the position of the gamma ray transmitting module of claim 2.

[0061] Finally, if Figure 4 As shown in the schematic diagram of the position of the gamma ray emission module of the embodiment of the present disclosure, it is stipulated that the position of the gamma ray is located on the straight line determined by the center point of the cube and the three vertices (L, 0, L), (0, L, L), and (L, L, L), and its direction is the direction from the center point to the vertex. In addition, the emission angle of the gamma ray needs to meet certain conditions (greater than β) to cover the effective positioning area, and its maximum width is the diagonal of the cube. The emission angle of the gamma ray emission module can be calculated through parameters such as the gamma ray position and the effective positioning area; Figure 5 The figure is a schematic diagram of calculating the emission angle of the gamma-ray emission module of the embodiment of the present disclosure, wherein the AC and BC sides are the diagonals of one face of the cube, with a length of √2L, DC is the effective detection distance R of the gamma ray, and the length of EC is half of the diagonal of the cube. The emission angle calculation formula of the gamma-ray emission module is as follows:

[0062]

[0063] Step 3: Time measurement; The embodiment of the present application provides a time digital converter (TDC) designed based on a field programmable logic device FPGA to achieve high-precision time interval measurement at a lower constant frequency. The specific implementation plan is as follows:

[0064] The method of combining "coarse time measurement" and "fine time measurement" is adopted to achieve the coarse time measurement. The coarse time measurement adopts the direct counting method, that is, the time interval is counted to obtain the rough time result. The formula is as follows:

[0065] T 粗 =n*T clk

[0066] Where T 粗 represents the coarse time measurement result, n is the number of counters, T clk For coarse measurement always cycle.

[0067] Fine time measurement uses the measurement scheme of the vernier delay chain. Figure 6Schematic diagram of the vernier delay chain used in the embodiment of the present disclosure. This measurement scheme is designed with reference to the vernier caliper, and two delay chains are constructed using the delay units inside the FPGA. The delays of the delay units used in the two delay chains are different, set to t1 and t2. t1 is the delay time of the slow chain delay unit, and t2 is the delay time of the fast chain delay unit, that is, t1>t2. During operation, the start signal is input to the slow chain for delay, and the output end of each delay unit is connected to the next delay unit and connected to the data input end of the D flip-flop. The end signal is input to the slow chain for delay, and the input of each delay unit is connected to the input end of the next delay unit and also to the clock end of the D flip-flop. As the name implies, the transmission speed of the start signal in the slow chain is less than the transmission speed of the end signal in the fast chain, so the end signal will definitely catch up with the start signal at a certain moment and exceed the start signal. When the end signal lags behind the stop signal, the output of the D flip-flop is 1 (the start signal and the stop signal are both valid at high level), and when the end signal is ahead of the start signal, the output of the D flip-flop is 0. At the end of the measurement, the register will output a set of thermometer codes. The time interval between the start signal and the end signal can be calculated based on the number of 1s in the thermometer code, that is, the fine time measurement result, recorded as Δt, N is the number of "1" output by the D flip-flop, and the calculation formula is as follows:

[0068] Δt=N*(t1-t2)

[0069] Step 4: Position calculation: By collecting the time difference of the photoelectric signal obtained on the located sensor, the distance between the located terminal and each transmitting module can be calculated, and the precise position of the located terminal in the medium can be further obtained. The specific implementation plan is as follows:

[0070] First, the gamma ray shielding module switch is controlled by a periodic signal, and the opening time t of the gamma ray shielding module is recorded. s1 With duration t s2 ; Then, by selecting the output channel of the periodic signal controlled by the circuit, the clock signal is controlled to be output to different ray shielding modules in turn, and three clock cycles constitute a measurement cycle; secondly, the integrated high-sensitivity photoelectric sensor module located in the measured area collects gamma rays and records the collection start time t r1 With duration t r2 ; Again, by calculating t s1 ,t r1 The time difference can be used to calculate the distance from the positioned end (sensor) to each gamma ray emission module; and the time difference T between the sensor receiving each emission module in the current measurement period is recorded. S The time difference T between the last measurement cycle and the last measurement cycle L , calculate the time difference between the two, and further calculate the distance change between the located terminal and each transmitting module. The calculation formula is as follows:

[0071] S=C×(t r1 -t s1 )

[0072] ΔS=C×(T S -T L )

[0073] Where S is the distance from the sensor to the corresponding gamma ray emission module, C is the speed of light, and ΔS is the distance the sensor moves in one positioning cycle. Finally, the photon detection sensor positioning method according to claim 5 is characterized in that the sensor position information is calculated using a three-ball positioning method. Figure 7 This is a schematic diagram of the three-ball positioning principle used in the embodiment of the present disclosure. The specific formula is as follows:

[0074]

[0075] Where S i represents the distance from the sensor to the i-th gamma-ray emission module, (x i ,y i , z i ) represents the position coordinates of the i-th gamma-ray emission module, and (x, y, z) represents the sensor coordinates to be solved. However, the positioning system itself will have measurement errors, and the solution to the position solution equation may not exist. The least squares method is introduced during the solution to obtain an approximate solution to the solution equation group.

[0076] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the specific steps of the positioning method based on the photon detection sensor of the present invention when executing the computer program. The positioning method based on the photon detection sensor of the present invention can be implemented in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention can be implemented in the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. If the positioning method based on the photon detection sensor of the present invention is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, in an exemplary embodiment, a computer-readable storage medium is also provided, and the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in the computer-readable storage medium, and the computer program can be implemented by the processor when it is executed, The steps of each method embodiment described above. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form, etc. Computer-readable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals. Among them, the computer storage medium can be any available medium or data storage device that can be accessed by a computer, including but not limited to magnetic storage (such as floppy disks, hard disks, tapes, magneto-optical disks (MO), etc.), optical storage (such as CD, DVD, BD, HVD, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NANDFLASH), solid-state hard disk (SSD)), etc. In an exemplary embodiment, a computer device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the gamma radiation source positioning method when executing the computer program.The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0077] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A positioning method based on a photon detection sensor, characterized in that: The steps include: S1: Obtain the geometric parameters of the area to be determined and establish a spatial model of the effective positioning area; S2: Obtain parameters of the photoelectric detector and the gamma-ray emission device group, and calculate the position, power and angle of the gamma-ray emission device group according to the effective positioning area described in S1; S3: Collect the time difference between gamma ray emission and reception, calculate the distance between the transmitting module and the sensor, and further calculate the sensor position information using the three-ball positioning principle; S4: Based on the positioning scheme of S3, a time-to-digital converter (TDC) is designed to improve the time measurement accuracy and further improve the accuracy of the positioning system.

2. A positioning method based on a photon detection sensor according to claim 1, characterized in that: In S1, a spatial origin and a basic plane (XY plane) are determined, and an effective positioning area is set according to the actual area to be positioned, the effective positioning area simultaneously includes the actual positioning area and a cube area with a 10% margin, the actual positioning area and the cube area have the same geometric center, one vertex of the cube is the origin, the side length of the cube is L, and the vertex coordinates are the origin (X0, Y0, Z0), (L, 0, 0), (0, L, 0), (0, 0, L), (L, L, 0), (L, 0, L), (0, L, L), (L, L, L); the method for setting the 10% margin is: determine the geometric center of the actual positioning area, and construct a cuboid with a maximum side length of l that is tangent to the actual positioned area with the geometric center, L = 1.2l, so the distance between the cube and the long boundary surface is 0.1l.

3. A positioning method based on a photon detection sensor according to claim 1, characterized in that: In S2, the position of the gamma-ray emission module is calculated according to the effective positioning area of ​​the cube, and a spatial calculation model of the gamma-ray emission device group is established. The calculation basis is as follows: First of all, the formula for calculating gamma ray energy is based on electromagnetic wave theory, and the formula for ray energy is: E=h*f*(1-e -αr ) Where E is the energy of the gamma ray, which is related to the transmitter power, h is Planck's constant, f is the frequency of the gamma ray, α is the attenuation coefficient of the gamma ray, and r is the distance the gamma ray propagates. That is, when the transmitter module power is determined, the energy of the ray received by the area at a distance r from the transmitter module is fixed; Secondly, the relevant formula for the photoelectric sensor is as follows: i=KI Wherein i is the current generated by the photoelectric sensor, K is the photoelectric sensitivity of the photoelectric sensor, I is the light intensity, P is the power of light, and A is the surface area of ​​the sensor; the intensity of the gamma ray received by the sensor at a distance r from the transmitting module is proportional to its energy at that point, and the current generated is proportional to the light intensity; when the sensitivity of the sensor is fixed, its maximum distance from the gamma ray is fixed, and the specific position information of the gamma ray transmitting device group can be obtained according to the gamma ray transmitting module position confirmation method of claim 2; Finally, it is stipulated that the position of the gamma ray is located on the straight line determined by the center point of the cube and the three vertices (L, 0, L), (0, L, L), and (L, L, L), and its direction is the direction from the center point to the vertex; the emission angle of the gamma ray needs to meet certain conditions (greater than) to cover the effective positioning area, and the calculation formula is as follows:

4. The positioning method based on a photon detection sensor according to claim 1, characterized in that: The gamma-ray emitting device group includes at least three groups of gamma-ray emitting devices, and the gamma-ray emitting device consists of a gamma-ray emitting module and a ray shielding module; the ray emitted by the emitting module is a conical area of ​​a certain angle, and the area should cover the effective positioning area; the ray shielding module is a lead plate, and closing the ray shielding module can prevent the ray emitted by the gamma-ray emitting module from reaching the effective positioning area, otherwise the ray can reach the effective positioning area.

5. The positioning method based on a photon detection sensor according to claim 1, characterized in that: In S3, the time difference of the photoelectric signal obtained by the located sensor is collected to calculate the distance between the located terminal and each transmitting module, and further obtain the precise position of the located terminal in the medium. The specific implementation scheme is as follows: First, the gamma ray shielding module switch is controlled by a periodic signal, and the opening time t of the gamma ray shielding module is recorded. s1 With duration t s2 ; Then, by selecting the output channel of the periodic signal controlled by the circuit, the clock signal is controlled to be output to different ray shielding modules in turn, and three clock cycles constitute a measurement cycle; secondly, the integrated high-sensitivity photoelectric sensor module located in the measured area collects gamma rays and records the collection start time t r1 With duration t r2 ; Again, by calculating t s1 ,t r1 The time difference can be used to calculate the distance from the positioned end (sensor) to each gamma ray emission module; and the time difference T between the sensor receiving each emission module in the current measurement period is recorded. S The time difference T between the last measurement cycle and the last measurement cycle L , calculate the time difference between the two, and further calculate the distance change between the located terminal and each transmitting module. The calculation formula is as follows: S=C×(t r1 -t s1 ) ΔS=C×(T S -T L ) Where S is the distance from the sensor to the corresponding gamma ray emission module, C is the speed of light, and is the distance the sensor moves in one positioning cycle; Finally, according to the photon detection sensor positioning method of claim 5, it is characterized in that the three-ball positioning method is used to solve the sensor position information, and the specific formula is as follows: where represents the distance from the sensor to the i-th gamma-ray emission module, (x i ,y i , z i ) represents the position coordinates of the i-th gamma-ray emission module, and (x, y, z) represents the sensor coordinates to be solved; however, the positioning system itself may have measurement errors, and the solution to the position solution equation may not exist. The least squares method is introduced during the solution to obtain an approximate solution to the solution equation group.

6. A positioning method based on a photon detection sensor according to claim 5, characterized in that: The following steps are also included to improve the stability and positioning accuracy of the positioning system: S3.1: First, fix the positioned end at a spatial point with known position information by calibrating the mechanical bracket, and enter the position information of the positioned end; secondly, control the gamma ray emission module to emit gamma rays, and obtain the time information described in claim 5 through the positioned end, and calculate the measurement value of the positioned end; then, repeat the above steps to obtain multi-point spatial information (measured value and actual value); finally, use the least squares method to obtain the calibration coefficient, and introduce the coefficient for correction when performing position solution.

7. A positioning method based on a photon detection sensor according to claim 1, characterized in that: In the S4, a time-to-digital converter (TDC) is designed based on a field programmable logic device FPGA to achieve high-precision time interval measurement at a relatively low clock frequency.

8. A positioning device based on a photon detection sensor according to claims 1-7, characterized in that: The invention comprises an integrated high-sensitivity photoelectric sensor module, a gamma-ray emission component, a weak electric signal amplification and collection circuit, a signal processing circuit, a medium conduit, a calibration bracket, and a program and a memory for realizing the positioning method; the integrated high-sensitivity photoelectric sensor module is embedded in the head end of the medium conduit as a positioned terminal, and is used to collect gamma-ray energy and convert it into a current signal. The electric signal is used as an input signal of a low-noise amplifier through a thin wire in the medium conduit, and is sampled by an ADC module after amplification; the wire has a diameter of 1 mm, and the cut-off conduit has a diameter of 10 mm; The medium conduit is hard-linked to the weak signal amplification and collection circuit to protect the wire from damage; the gamma ray emission component is composed of a gamma ray emission module, a controllable ray shielding module, a motion mechanical arm, etc.

9. A positioning device based on a photon detection sensor according to claim 8, characterized in that: The positioning device realizes system control signal generation, data acquisition and processing, time interval measurement and other functions based on FPGA. The positioning device includes a gamma ray emission control module, a robotic arm motion control module, a data acquisition module, a signal processing module, and a time measurement module.

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