TWI580987B - A positioning algorithm for calculating the positioning distance - Google Patents

Description

Positioning algorithm for calculating the positioning distance

The invention relates to a positioning algorithm for calculating a positioning distance, in particular to using a wireless communication method to transmit a frequency difference between a frequency modulated frequency transmitted by a positioning signal transceiver unit and a positioning frequency, and to calculate a distance and a position. The algorithm of the coordinates.

At present, due to the linear frequency modulated continuous wave radar system, the farther the echo frequency signal will be smaller due to the target distance, the signal intensity will gradually become smaller or even lower than the near field noise level, which means that the height sensor system falls close to the ground. , the target height will not be solved correctly, resulting in a decrease in distance detection capability.

In the prior art, as disclosed in European Patent No. EP 1 602 939 A1, a frequency using a modulated continuous wave (FM-CW) method is known. A radiation positioning system is known from radar technology and incorporates a passive antenna through which the impedance passes through the label. The tag modulated by the device of the generated subcarrier. In an extended embodiment, the identification number of the tag is transferred to the interrogation unit by means of modulation of the subcarriers. Application areas: tracking out-of-control, pets, cattle, cargo and humans, biometric telemetry and other mobile records.

In the above techniques, there is no further disclosure on how to achieve orthopedic surgery. Required positioning feedback accuracy requirements and 3D positioning.

The object of the present invention is to provide a positioning algorithm for calculating a positioning distance, which transmits a frequency modulated signal to a positioning target implanted on each vertebra of the spine by an adjustable frequency positioning signal transmitting and receiving unit, and the positioning target reflects the frequency modulated signal. The distance is calculated by the frequency difference between the frequency modulated signals at the time of transmission and reception, and the coordinate positioning is completed, thereby independently tracking and calculating the posture and position of the spine, avoiding the spine as a rigid body, and lifting the spinal joint Positioning accuracy, improve the accuracy and safety of the pedicle screw.

The positioning algorithm for calculating the positioning distance is as follows: transmitting a frequency-modulated frequency signal to a positioning target through a positioning signal transceiver unit; receiving the positioning frequency signal by receiving the frequency-modulated frequency signal from the positioning target to The positioning signal transceiver unit calculates a distance value between the positioning signal transceiver unit and the positioning target by using a frequency modulated continuous waveform (FMCW) positioning algorithm according to the frequency modulation frequency signal and the positioning standard frequency signal. Using a phase interference analysis algorithm to improve the accuracy of the positioning target frequency signal; and combining a triangulation method to obtain a spatial positioning coordinate of the positioning signal transceiver unit and the positioning target.

This patent is aimed at the attenuation and encountering interference of near-field noise and target signal strength. It is based on the characteristics of cyclotron integral, window function, FFT and radar receiving power loss and square of ground target. The signal compensation method and the simulation result prove that the design scheme is effective. In addition to improving the noise, the signal strength is enhanced, the correct information is obtained, and the error is low, which is in line with the acceptable range of the ranging accuracy, which promotes the overall system application level.

10‧‧‧ Positioning Module

11‧‧‧Spine

12‧‧‧ Positioning

12A, 12B‧‧‧ antenna

12A1, 12B1‧‧‧ positioning standard frequency signal

13A, 13B‧‧‧ Antenna

13A1, 13B1‧‧‧ device frequency signal

121‧‧‧ Positioning frequency signal

121A‧‧‧ID

13‧‧‧Surgical instruments

131‧‧‧Device frequency signal

131A‧‧‧Device ID

14‧‧‧Location signal transceiver unit

141‧‧‧FM frequency signal

L1, L11‧‧‧ positioning distance

L2, L21‧‧‧ instrument distance

20‧‧‧Processing unit

30‧‧‧Surgical images

31‧‧‧Spine image

311‧‧‧Spine Space Coordinates

32‧‧‧Surgical instrument images

321‧‧‧ device space coordinates

S710~S760‧‧‧Step process

D1, D2‧‧‧ signal difference

T1‧‧‧ time

S1, S2‧‧‧ angle

1 is a schematic view of the present invention applied to a surgical navigation operation.

2 is a block diagram of the present invention applied to a surgical navigation operation.

3A and 3B are schematic diagrams of the frequency modulation frequency signal of the present invention.

4 is a schematic diagram of an image of the present invention applied to a surgical navigation operation.

FIG. 5 is a schematic diagram of a positioning target antenna applied to a surgical navigation operation according to the present invention.

Fig. 6 is a schematic view showing the antenna of the surgical instrument applied to the surgical navigation operation of the present invention.

7 is a flow chart showing the steps of a positioning algorithm for calculating a positioning distance according to the present invention.

The above and other objects, features, and advantages of the present invention will become more apparent from the following description.

Please refer to FIG. 1 to FIG. 7. FIG. 1 is a schematic diagram of the present invention applied to a surgical navigation operation, FIG. 2 is a block diagram of the present invention applied to a surgical navigation operation, and FIGS. 3A and 3B are frequency modulation frequencies of the surgical navigation operation of the present invention. FIG. 4 is a schematic diagram of an image of a positioning target antenna used in a surgical navigation operation according to the present invention, and FIG. 6 is a schematic diagram of a surgical instrument antenna used in a surgical navigation operation according to the present invention. 7 series of the invention A flow chart of the steps of the positioning algorithm for calculating the positioning distance.

First, the spinal CT (Computed tomography) image is taken before the spinal surgery, and then the C-arm image of the positioning target 12 of the present invention which has been implanted on the spine is photographed, and then the two images are superimposed into the surgical image. 30. The surgical image 30 can include the spinal image 31 and the surgical instrument image 32, and then the navigation module for calculating the positioning distance according to the present invention is used to facilitate the surgical navigation operation. The positioning module 10 of the present invention includes: The positioning signal transceiver unit 14 is configured to transmit the frequency modulation frequency signal 141 to the plurality of positioning targets 12 and the surgical instrument 13.

Furthermore, the frequency range of the positioning signal transceiving unit 14 is 24-24.4 GHz, and the positioning signal transceiving unit 14 adds a switching modulation mechanism, which can separate the environmental clutter and the echo signal of the target in the spectrum, and reduce the environment. The interference is further improved by the modulation mechanism of the positioning signal transceiver unit 14 so that the frequency signals sent by the positioning signal transceiver unit 14 have adjustable characteristics.

First, in step S710, a plurality of positioning targets 12 are respectively disposed on a vertebra of the vertebra 11, and each positioning target 12 is configured to receive the frequency-modulated frequency signal 141, and then return the positioning standard frequency signal 121 to the positioning signal transceiver unit. The positioning signal transceiver unit 14 receives the positioning target frequency signal 121, wherein the positioning target frequency signal 121 and the frequency modulation frequency signal 141 are the same waveform. In more detail, the positioning target 12 has an antenna, and when the antenna receives After the frequency modulation signal 141 is sent, the signal is reflected back to the positioning signal transceiver unit 14, so the positioning target The frequency signal 121 is the same waveform as the frequency modulation frequency signal 141.

In addition, the surgical device 13 is configured to receive the FM frequency signal 141 and return the device frequency signal 131 to the positioning signal transceiver unit 14. The positioning signal transceiver unit 14 receives the device frequency signal 131, wherein the device frequency signal 131 and The FM frequency signal 141 is the same waveform. In more detail, the surgical instrument 13 has an antenna. When the antenna receives the FM frequency signal 141, the signal is reflected back to the positioning signal transceiver unit 14, so that the device frequency signal 131 and The FM frequency signal 141 is the same waveform.

Next, in step S720, the processing unit 20 is electrically connected to the positioning signal transceiver unit 14. Referring to FIG. 3A, the signal difference D1 according to the positioning standard frequency signal 121 and the FM frequency signal 141 is also called a beat frequency, and the algorithm calculates the The positioning target distance between the positioning target 12 and the positioning signal transceiver unit 14 is L1, wherein the algorithm is a frequency modulated continuous waveform (FMCW) positioning algorithm, and the processing unit 20 receives the same according to the same time T1. The signal difference D1 between the positioning standard frequency signal 121 and the frequency modulation frequency signal 141 is also the beat frequency, to calculate the positioning target distance L1, and calculate the spinal space coordinate 311 according to the positioning target distance L1.

In the above, when the algorithm calculates the positioning target distance L1 between the positioning target 12 and the positioning signal transceiving unit 14, the first beat frequency ranging algorithm obtains a half wavelength error value close to the real distance, and then step S730 Then, a phase interference analysis algorithm is used to calculate the spatial positioning coordinate of the positioning signal transceiver unit and the positioning target according to the distance value and the half wavelength error value, further illustrating that the phase interference algorithm is as follows: s _b ( t )= B cos(2 π ( f _o - πα _o τ + α _o t ) τ )

When the radar carrier frequency (fo) is much larger than the beat frequency ( α ot), fo>> α aot, it can be simplified as: =2 π f _o τ -π ² α ₀ τ ² 2 π f _o τ ; it is also known that the radar accuracy is Since λ is the radar carrier wavelength, the accuracy can be further improved to .

In the above, in detail, since the transmission speed is fast and the time difference is extremely small, the present invention takes the same time T1 as the sampling.

In an embodiment, in step S740, the positioning signal transceiving unit 14 is at least two positioning signal transceiving units 14 respectively disposed on the periphery of the vertebra 11, and the processing unit 20 receives the two according to the two positioning signal transceiving units 14. The positioning target frequency signal 121 calculates the corresponding two positioning target distances L1 and L11, and then calculates the spinal space coordinate 311 by the triangulation method.

In addition, the processing unit 20 calculates the device distance L2 of the surgical instrument 13 and the positioning signal transceiving unit 14 by using a frequency modulation continuous wave positioning algorithm according to the signal difference D2 between the instrument frequency signal 131 and the FM frequency signal 141, according to and according to the The instrument space coordinate 321 is calculated from the instrument distance L2.

In one embodiment, the positioning signal transceiver unit 14 is at least two positioning signal transceiving units 14 respectively disposed on the periphery of the surgical instrument 13, and the processing unit 20 receives the two instruments according to the two positioning signal transceiving units 14. The frequency signal 131 calculates the corresponding two instrument distances L2 and L21, and then calculates the device space coordinate 321 by the triangulation method.

In the above, the spatial positioning coordinate of the present invention is exemplified by the positioning signal transmitting and receiving unit being a three transmitting and receiving positioning signal transmitting and receiving unit. The spatial positioning coordinate is (X, Y), and the coordinate solution is: The coordinates of the three transmitting and receiving positioning signal transceiver units are ( X _a , Y _a ), ( X _b , Y _b ) and ( X _c , Y _c ), and the distance between the three transmitting and receiving positioning signal transceiver units and the positioning target is d _a , d _b and d _c .

Further, please refer to FIG. 4 , the positioning target 12 further includes an identification code 121A, and the surgical instrument 13 further includes a device identification code 131A (the symbol of FIG. 4 is incorrect), and the positioning signal transceiving unit 14 is configured to receive the identification code 121A. After the device identification code 131A, the processing unit 20 defines the identification code 121A to the corresponding spinal space coordinate 311, and the processing unit 20 defines the device identification code 131A to the corresponding device space coordinate 321 The identification code 121A and the device identification code 131A can confirm whether the corresponding positioning target 12 and the surgical instrument 13 are correct.

For further description, referring to FIG. 5, each of the positioning targets 12 further includes at least two antennas 12A and 12B. After receiving the frequency-modulated frequency signal 141, the two positioning target frequency signals 12A1 and 12B1 are returned to the positioning signal transceiver unit 14 . The processing unit 20 is calculated by the two positioning target frequency signals 12A1 and 12B1. The distance between the two antennas 12A, 12B and the positioning signal transceiving unit 14 is calculated, thereby calculating an angle S1 between the implant 12 and the pre-fabrication surgical navigation path to confirm that the positioning target is implanted into the implant Whether it is the same as the pre-construction surgery navigation path.

In addition, referring to FIG. 6 , the surgical instrument 13 further includes at least two device antennas 13A and 13B. After receiving the frequency modulation frequency signal 141 , the two device frequency signals 13A1 and 13B1 are returned to the positioning signal transceiver unit 14 . The processing unit 20 calculates the distance between the two antennas 13A and 13B of the device and the positioning signal transceiving unit 14 by using the two device frequency signals 13A1 and 13B1, thereby calculating an angle S2 between the surgical instrument and the pre-installation surgical navigation path. To confirm whether the operation of the surgical instrument is the same as the pre-installation surgical navigation path.

As described above, with the present invention, preoperative planning information can be imported prior to spinal surgery, and then surgical navigation operations can be performed based on the spatial coordinates of the spinal space, the space coordinates of the instrument, the positioning target, and the angle of the surgical instrument.

The invention utilizes wireless positioning technology to realize multi-vertebral positioning tracking and navigation surgery technology, and adopts a frequency-modulated radio frequency positioning technology and an identification code identification function to set a positioning antenna mark on a vertebra, and locates an antenna-marked vertebra through independent tracking setting instead of using The numerical calculation method regards all the spines as rigid bodies, thereby improving the accuracy and speed of medical image registration (accelerated calculation convergence), improving the safety and precision of surgical implants, and the navigation system is suitable for long spinal surgery (spine side). Bending correction, multi-segmental spinal fractures, so that the operation is not limited by the large infrared reflective ball positioning marker device.

The invention can effectively improve the safety and quality of the operation of the spine surgery, reduce the use of the penetrating medical image during the operation and reduce the amount of free radiation absorbed by the medical staff; and the medical image navigation technology is the main core foundation of the future intelligent surgical assist system. In the future, combined with surgical robotic arm and high-focus penetrating therapeutic equipment (HIFU, gamma knife, proton therapy), high-precision treatment can be achieved, and postoperative complications and effects can be reduced.

In summary, it is merely described that the present invention is an implementation or embodiment of the technical means employed to solve the problem, and is not intended to limit the scope of implementation of the present patent. Any change or modification that is consistent with the scope of the patent application scope of this creation or the scope of the patent creation is covered by the scope of the creation patent.

S710~S740‧‧‧Step process

Claims (5)

A positioning algorithm for calculating a positioning distance is as follows: transmitting a frequency-modulated frequency signal to a positioning target through a positioning signal transceiver unit; receiving the positioning frequency signal by the positioning target and transmitting a positioning standard frequency signal to the positioning a signal transceiving unit; according to the frequency modulation frequency signal and the positioning target frequency signal, calculating a distance value between the positioning signal transceiver unit and the positioning target through a frequency modulated continuous waveform (FMCW) positioning algorithm; A phase interference analysis algorithm is used to improve the accuracy of the positioning frequency signal; and a positioning method is used to obtain a spatial positioning coordinate of the positioning signal transceiver unit and the positioning target. The positioning algorithm for calculating the positioning distance according to the first application of the patent scope, the frequency modulation frequency signal and the positioning standard frequency signal are calculated by a frequency modulated continuous waveform (FMCW) positioning algorithm. In the step of the distance value between the positioning signal transceiver unit and the positioning target, the distance value is calculated according to the beat frequency of the positioning target frequency signal and the frequency modulation frequency signal received at the same time. The positioning algorithm for calculating the positioning distance as described in claim 1, wherein the phase interference analysis algorithm is s _b ( t )= B cos(2 π ( f _o - πα _o τ + α _o t ) τ ), the accuracy is The positioning algorithm for calculating the positioning distance as described in claim 1 of the patent application, wherein the frequency modulation frequency signal is 24 to 24.4 GHz. The positioning algorithm for calculating the positioning distance according to claim 3, wherein the positioning signal transceiver unit is a three-transceive positioning signal transceiver unit, and the spatial positioning coordinate is ( X, Y ), and the coordinate solution is: The coordinates of the three transmitting and receiving positioning signal transceiver units are ( X _a , Y _a ), ( X _b , Y _b ) and ( X _c , Y _c ), and the distance between the three transmitting and receiving positioning signal transceiver units and the positioning target is d _a , d _b and d _c .