CN115641730A

CN115641730A - Multi-feature fusion vehicle detection method based on geomagnetic sensor

Info

Publication number: CN115641730A
Application number: CN202211179700.2A
Authority: CN
Inventors: 柳革命; 柳师捷; 刘国福; 李岩; 刘婵娟
Original assignee: Guangzhou College Of Commerce
Current assignee: Guangzhou College Of Commerce
Priority date: 2022-09-27
Filing date: 2022-09-27
Publication date: 2023-01-24

Abstract

The invention discloses a multi-feature fusion vehicle detection method based on a geomagnetic sensor, which comprises the following steps: acquiring geomagnetic field component values in the X-axis direction and the Y-axis direction through the first geomagnetic sensor group and the second geomagnetic sensor group, and calculating geomagnetic field information of the parking space; performing feature extraction according to the geomagnetic field information to obtain a target feature group; and performing multi-feature fusion judgment according to the target feature group to obtain a vehicle detection result. The invention improves the accuracy and can be widely applied to the technical field of computers.

Description

Multi-feature fusion vehicle detection method based on geomagnetic sensor

Technical Field

The invention relates to the technical field of computers, in particular to a multi-feature fusion vehicle detection method based on a geomagnetic sensor.

Background

With the increasing amount of vehicles kept, a large number of motor vehicles can only be parked on roadways or temporary parking areas. The roadside temporary parking lot size accounts for about 58% of the entire public parking lot size. Roadside parking spaces are public resources, and it has become a consensus to charge for occupied parking. The current situation of roadside parking space charging is generally a manual charging mode and an unmanned charging mode. In both charging modes, a sensor is needed to detect whether a vehicle is stored in the parking space. Under the manual charging mode, the detector is installed below each parking space, and the working strength of manual charging can be reduced. Under the unmanned charging mode, whether a vehicle is parked on the parking space can be effectively detected through the detection sensor so as to finish self-service payment, autonomous declaration and unmanned payment management.

There are various methods for detecting vehicles in a parking space, such as laser infrared detection, ultrasonic detection, magnetic field detection, etc. For vehicle detection on roadside parking places, a geomagnetic field measurement sensor is an optimal detection means, and a detection method based on the detection means is also a better detection method which is generally accepted at present. The automobile is a vehicle wrapped by an iron shell, and a magnetic field exists around the automobile. The movement of the vehicle affects the change of the peripheral magnetic field. Similarly, when the vehicle is parked in a parking space, the peripheral magnetic field changes. The principle of detecting the change of the magnetic field is used for detecting whether a vehicle is parked on a parking space, and the sensor is called as an earth magnetic field measuring sensor in the industry and is called as a geomagnetic sensor for short.

The geomagnetic measurement technology is a technology for measuring the change of the geomagnetism of an automobile entering a specific area by using a geomagnetic sensor so as to judge the state of the automobile, and is a key technology in an intelligent traffic system. In recent years, the development of the geomagnetic measurement technology enables a geomagnetic sensor to have the characteristics of small size, low power consumption, high cost performance, simplicity in installation and construction (extremely small damage to the earth surface), easiness in maintenance and the like, and the geomagnetic sensor is widely applied to intelligent transportation, parking space vehicle detection and intelligent toll collection systems. However, in the detection of vehicles at roadside and parking places, the detection is based on a single geomagnetic measurement technology, also called a single-mode identification technology based on the geomagnetic, and has the problems of poor anti-interference capability, difficulty in determining the discrimination threshold values at different places, and high error probability. At present, a dual-mode geomagnetic-based identification technology is commonly adopted for roadside parking space vehicle detection, namely a geomagnetic measurement technology and another supplementary technology. For example, based on geomagnetic and radar detection technologies, a parking space sensor integrating geomagnetic and radar detection technologies is utilized, geomagnetic as static detection and radar as dynamic detection are combined, and the accuracy of vehicle detection is improved; based on detection of the geomagnetic sensor and the ultrasonic sensor, when a vehicle enters or leaves, the geomagnetic sensor detects the change of a magnetic field, the ultrasonic unit is awakened, the distance from a vehicle chassis to the detector is measured, and finally vehicle state information is confirmed; the parking space vehicle detection based on the geomagnetic and UWB technology is used for assisting the UWB distance measurement technology on the basis of detecting the intensity change of a geomagnetic signal, performing data fusion and confirming the information of the vehicle, so that the interference of the vehicle on the adjacent parking space is effectively reduced, and the detection accuracy is improved; vehicle detection based on earth magnetism and optical sensor technique utilizes the shadow that the optical sensor of extremely low consumption detected the vehicle and got into the parking stall, and then starts earth magnetism detecting element work, and this kind of technique greatly reduced detecting system's consumption. In addition, research and application are also being made on vehicle detection by geomagnetic and geomagnetic coils, vehicle detection by geomagnetic and infrared sensors, and the like.

Disclosure of Invention

In view of this, the embodiment of the invention provides a high-accuracy multi-feature fusion vehicle detection method based on a geomagnetic sensor.

One aspect of the embodiments of the present invention provides a multi-feature fusion vehicle detection method based on a geomagnetic sensor, including:

acquiring geomagnetic field component values in the X-axis direction and the Y-axis direction through the first geomagnetic sensor group and the second geomagnetic sensor group, and calculating geomagnetic field information of the parking space;

performing feature extraction according to the geomagnetic field information to obtain a target feature group;

and performing multi-feature fusion judgment according to the target feature group to obtain a vehicle detection result.

Optionally, the obtaining, by the first geomagnetic sensor group and the second geomagnetic sensor group, geomagnetic field component values in an X-axis direction and a Y-axis direction, and calculating geomagnetic field information of the parking space includes:

acquiring geomagnetic field component values in the X-axis direction and the Y-axis direction through the first geomagnetic sensor group and the second geomagnetic sensor group;

calculating a first order difference of geomagnetic measurement values in the X direction according to the X-axis magnetic field component value output by the first geomagnetic sensor group and the X-axis magnetic field component value output by the second geomagnetic sensor group;

calculating a first order difference of the geomagnetic measurement values in the Y direction according to the Y-axis magnetic field component values output by the first geomagnetic sensor group and the Y-axis magnetic field component values output by the second geomagnetic sensor group;

calculating a system error of the first-order difference in the X direction according to the first-order difference of the geomagnetic measurement value in the X direction;

calculating a system error of the first-order difference in the Y direction according to the first-order difference of the geomagnetic measurement value in the Y direction;

calculating the deviation of the first order difference of the geomagnetic measurement value in the X direction according to the first order difference of the geomagnetic measurement value in the X direction and the system error of the first order difference in the X direction;

calculating the deviation of the first order difference of the geomagnetic measurement value in the Y direction according to the first order difference of the geomagnetic measurement value in the Y direction and the system error of the first order difference in the Y direction;

calculating the sum of the deviations of the first order differences of the geomagnetic measurement values in the X and Y directions according to the deviation of the first order differences of the geomagnetic measurement values in the X direction and the deviation of the first order differences of the geomagnetic measurement values in the Y direction;

calculating the XY plane geomagnetic vector direction angle measured by the first geomagnetic sensor group according to the X-axis magnetic field component value output by the first geomagnetic sensor group and the Y-axis magnetic field component value output by the first geomagnetic sensor group;

calculating the geomagnetic vector direction angle in the XY plane measured by the second geomagnetic sensor group according to the X-axis magnetic field component value output by the second geomagnetic sensor group and the Y-axis magnetic field component value output by the second geomagnetic sensor group;

and calculating a first order difference of the geomagnetic vector direction angles of the XY plane according to the geomagnetic vector direction angles of the XY plane measured by the first geomagnetic sensor group and the geomagnetic vector direction angles of the XY plane measured by the second geomagnetic sensor group.

Optionally, the method further comprises a step of signal preprocessing according to the geomagnetic field information, the step comprising:

a sensor unit is arranged at the geometric center of the roadside parking space;

when the X component value or the Y component value measured by the sensor unit exceeds a preset strong geomagnetic threshold, determining that a non-target vehicle passes through;

under the condition that no vehicle exists in the parking space, measuring an X component value, a Y component value and a Z component value of the geomagnetic field in a plurality of cycles, and determining an interference signal containing a basic value of the geomagnetism and the influence of the surrounding environment of the parking space.

Optionally, the performing feature extraction according to the geomagnetic field information to obtain a target feature group includes:

acquiring geomagnetic field component values in X-axis and Y-axis directions according to the first geomagnetic sensor group and the second geomagnetic sensor group, and determining the deviation of first-order difference of geomagnetic measurement values in the X direction and the deviation of first-order difference of geomagnetic measurement values in the Y direction;

determining the sum of the deviations of the first order differences of the geomagnetic measurement values in the X and Y directions according to the deviation of the first order differences of the geomagnetic measurement values in the X direction and the deviation of the first order differences of the geomagnetic measurement values in the Y direction;

acquiring a geomagnetic vector direction angle in an XY plane according to the first geomagnetic sensor group and the second geomagnetic sensor group, and determining a first difference of the geomagnetic vector direction angles in the XY plane;

acquiring geomagnetic component values in the Y-axis direction according to the second geomagnetic sensor, and determining the deviation of the geomagnetic component values in the Y-axis;

and constructing to obtain a target feature set according to the deviation of the first-order difference of the geomagnetic measurement values in the X direction, the deviation of the first-order difference of the geomagnetic measurement values in the Y direction, the sum of the deviations of the first-order differences of the geomagnetic measurement values in the X direction and the Y direction, the first-order difference of the geomagnetic vector direction angles in the XY plane and the deviation of the magnetic field component values in the Y axis.

Optionally, the performing multi-feature fusion judgment according to the target feature group to obtain a vehicle detection result includes:

under the condition that no vehicle occupies the parking space, judging whether the vehicle enters or not by adopting a plurality of different characteristics, and fusing a plurality of judgment results to obtain a judgment result;

and under the condition that the vehicle occupies the parking space, judging whether the vehicle drives away by adopting a plurality of different characteristics, and fusing a plurality of judgment results to obtain a judgment result.

Optionally, in the state that no vehicle occupies the parking space, determining whether the vehicle enters by using a plurality of different characteristics, and fusing a plurality of determination results to obtain a determination result, including:

firstly, acquiring the sum of the first-order difference deviations of the geomagnetic measurement values in the X direction and the Y direction, determining geomagnetic value variation when the sum of the first-order difference deviations of the geomagnetic measurement values in the X direction and the Y direction is more than 25, and judging that the vehicle enters a parking space for the first time;

secondly, obtaining a first difference of geomagnetic vector direction angles of the XY plane, and determining geomagnetic value variation when the first difference of the geomagnetic vector direction angles of the XY plane is larger than 0.2, and judging that the vehicle enters;

thirdly, the deviation of the component value of the magnetic field on the Y axis output by the second geomagnetic sensor is greater than or equal to 30, and the vehicle is judged to enter the parking space again;

finally, if the deviation of the first order difference of the geomagnetic measurement value in the X direction is greater than or equal to the positive threshold, or the deviation of the first order difference of the geomagnetic measurement value in the Y direction is greater than or equal to the positive threshold, or the deviation of the first order difference of the geomagnetic measurement value in the X direction is less than or equal to the negative threshold, or the deviation of the first order difference of the geomagnetic measurement value in the Y direction is less than or equal to the negative threshold, the vehicle is finally determined to enter the parking space, and the vehicle state of the parking space is adjusted to be in a vehicle occupation state.

Optionally, when the vehicle occupies the parking space, determining whether the vehicle is driven away by using a plurality of different characteristics, and fusing the plurality of determination results to obtain a determination result, including:

acquiring a deviation of a first order difference of the geomagnetic measurement values in the X direction, a deviation of a first order difference of the geomagnetic measurement values in the Y direction and a deviation of Y-axis magnetic field component values output by the second geomagnetic sensor;

and when the value of the deviation of the first order difference of the geomagnetic measurement values in the X direction is [ -10,10], the value of the deviation of the first order difference of the geomagnetic measurement values in the Y direction is [ -10,10], and the deviation value of the Y-axis magnetic field component value output by the second geomagnetic sensor is less than or equal to 30, determining that the vehicle has driven out, and adjusting the vehicle state of the parking space to a vehicle-free state.

In another aspect, an embodiment of the present invention further provides a multi-feature fusion vehicle detection apparatus based on a geomagnetic sensor, including:

the first module is used for acquiring geomagnetic field component values in the X-axis direction and the Y-axis direction through the first geomagnetic sensor group and the second geomagnetic sensor group and calculating geomagnetic field information of the parking space;

the second module is used for extracting features according to the geomagnetic field information to obtain a target feature group;

and the third module is used for carrying out multi-feature fusion judgment according to the target feature group to obtain a vehicle detection result.

Another aspect of the embodiments of the present invention further provides an electronic device, which includes a processor and a memory;

the memory is used for storing programs;

the processor executes the program to implement the method as described above.

Yet another aspect of the embodiments of the present invention provides a computer-readable storage medium, which stores a program, which is executed by a processor to implement the method as described above.

The embodiment of the invention also discloses a computer program product or a computer program, which comprises computer instructions, and the computer instructions are stored in a computer readable storage medium. The computer instructions may be read by a processor of a computer device from a computer-readable storage medium, and the computer instructions executed by the processor cause the computer device to perform the foregoing method.

The embodiment of the invention acquires geomagnetic field component values in X-axis and Y-axis directions through a first geomagnetic sensor group and a second geomagnetic sensor group, and calculates the geomagnetic field information of the parking space; performing feature extraction according to the geomagnetic field information to obtain a target feature group; and performing multi-feature fusion judgment according to the target feature group to obtain a vehicle detection result. The invention improves the detection accuracy.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic diagram of a hardware layout architecture of a geomagnetic sensor according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a geomagnetic sensor connection according to an embodiment of the present invention;

fig. 3 is a schematic diagram of an MSP430 connection according to an embodiment of the present invention;

FIG. 4 is a schematic circuit diagram of a power supply provided by an embodiment of the invention;

FIG. 5 is a flowchart illustrating the overall steps provided by an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In view of the problems in the prior art, an aspect of the embodiments of the present invention provides a multi-feature fusion vehicle detection method based on a geomagnetic sensor, including:

Optionally, the obtaining, by the first geomagnetic sensor group and the second geomagnetic sensor group, geomagnetic field component values in X-axis and Y-axis directions, and calculating geomagnetic field information of the parking space includes:

acquiring geomagnetic field component values in X-axis and Y-axis directions through the first geomagnetic sensor group and the second geomagnetic sensor group;

calculating a first order difference of geomagnetic measurement values in the Y direction according to the Y-axis magnetic field component value output by the first geomagnetic sensor group and the Y-axis magnetic field component value output by the second geomagnetic sensor group;

calculating the direction angle of the geomagnetic vector in the XY plane measured by the first geomagnetic sensor group according to the X-axis magnetic field component value output by the first geomagnetic sensor group and the Y-axis magnetic field component value output by the first geomagnetic sensor group;

and calculating a first difference of the geomagnetic vector direction angles in the XY plane according to the geomagnetic vector direction angles in the XY plane measured by the first geomagnetic sensor group and the geomagnetic vector direction angles in the XY plane measured by the second geomagnetic sensor group.

under the condition that no vehicle exists in the parking space, measuring an X component value, a Y component value and a Z component value of the geomagnetic field in a plurality of cycles, and determining a basic value containing the geomagnetism and an interference signal influenced by the surrounding environment of the parking space.

determining the sum of the first-order difference deviations of the geomagnetic measurement values in the X and Y directions according to the first-order difference deviation of the geomagnetic measurement value in the X direction and the first-order difference deviation of the geomagnetic measurement value in the Y direction;

and constructing to obtain a target feature set according to the deviation of the first-order difference of the geomagnetic measurement values in the X direction, the deviation of the first-order difference of the geomagnetic measurement values in the Y direction, the sum of the deviations of the first-order differences of the geomagnetic measurement values in the X and Y directions, the first-order difference of the direction angles of the geomagnetic vectors in the XY plane and the deviation of the component values of the magnetic fields in the Y axis.

under the condition that the parking space does not occupy the vehicle, judging whether the vehicle drives in by adopting a plurality of different characteristics, and fusing a plurality of judgment results to obtain a judgment result;

secondly, acquiring a first-order difference of the geomagnetic vector direction angles of the XY planes, and determining geomagnetic value difference when the first-order difference of the geomagnetic vector direction angles of the XY planes is larger than 0.2, and determining that the vehicle enters;

thirdly, if the deviation of the component value of the magnetic field on the Y axis output by the second geomagnetic sensor is greater than or equal to 30, the vehicle is judged to enter the parking space again;

Optionally, when the parking space is occupied by the vehicle, whether the vehicle is driven away is judged by adopting a plurality of different characteristics, and a plurality of judgment results are fused to obtain a judgment result, including:

acquiring a deviation of a first order difference of geomagnetic measurement values in the X direction, a deviation of a first order difference of geomagnetic measurement values in the Y direction and a deviation of Y-axis magnetic field component values output by a second geomagnetic sensor;

and when the value of the deviation of the first order difference of the geomagnetic measurement values in the X direction is-10, the value of the deviation of the first order difference of the geomagnetic measurement values in the Y direction is-10, and the value of the deviation of the Y-axis magnetic field component value output by the second geomagnetic sensor is less than or equal to 30, determining that the vehicle has run out, and adjusting the vehicle state of the parking space to a non-vehicle state.

Another aspect of the embodiments of the present invention further provides an electronic device, including a processor and a memory;

the memory is used for storing programs;

the processor executes the program to implement the method as described above.

The following detailed description of the embodiments of the invention is provided in conjunction with the accompanying drawings:

aiming at the problems in the prior art, the invention is based on a geomagnetic single mode detection technology, two groups of geomagnetic sensors are arranged in a detection unit, a set of method is designed, each group of geomagnetic sensors independently measures the geomagnetic component values of three axes X, Y and Z of a parking space, and an X-axis difference value and deviation thereof, a Y-axis difference value and deviation thereof, a Z-axis value, an XY plane geomagnetic vector direction angle and difference thereof are obtained through differential operation to form a judgment vector, and multi-level fusion judgment, so that the aim of greatly improving the detection probability of roadside parking spaces by the single mode geomagnetic technology is fulfilled, and the defect of a dual-mode detection algorithm of the roadside parking spaces based on the geomagnetism in the prior art is overcome.

The implementation process of the embodiment of the invention comprises two parts: the first part is the basis that the second part is realized.

A first part: the hardware layout of the geomagnetic sensor comprises four parts, namely a sensor unit (two groups of geomagnetic sensors), a central processing unit (MSP 430 single chip microcomputer system), a power supply module and a data wireless transmission module.

Referring to fig. 1, the sensor unit includes two independent sets of sensors, and a PNI3100 geomagnetic sensor is used (note: PNI3100 is a product model). The sensor consists of 2X/Y-axis magnetic field sensors Sen-XY-f (product model: 13104), 1Z-axis magnetic field sensor Sen-Z-f (product model: 13101) and 1 ASIC controller Mag12C (product model: 13156). The installation positions on the system circuit board are spaced by 12cm, and the variation of the real-time magnetic field when a vehicle enters a parking space, the measurement range of the sensor is-800 nT- +800nT, the sensitivity is 26nT, the high resolution and the low noise are respectively and independently measured, so that the sensor becomes a geomagnetic sensor with better performance in similar products. The connection principle is shown in fig. 2.

The central processing unit adopts a 16-bit MSP430 series single chip microcomputer, has the characteristics of ultra-low power consumption, wide voltage range, reduced Instruction Set (RISC), low clock frequency, high-speed communication realization, strong interruption capability, strong anti-interference capability and the like, is also called a mixed signal processor, integrates a plurality of analog circuits, digital circuit modules and microprocessors with different functions with one chip, and can well complete tasks of receiving, processing and sending measurement data and the like of the system. The connection schematic is shown in fig. 3.

Because the needs of this system are buried underground in parking stall ground, for reducing the maintenance cost, put forward higher requirement to the power. The system adopts an ER34615 capacity type lithium thionyl chloride (Li-SOCI 2) battery with the battery capacity of 19000mAH, and the connection schematic diagram is shown in figure 4.

The data wireless transmission unit adopts Narrow-Band Internet of Things (NB-IoT) technology, and the technology is mature. It consumes only about 180kHz bandwidth and can be deployed directly in GSM networks, UMTS networks or LTE networks. When the vehicle enters or exits the parking space, real-time geomagnetic measurement data and a judgment result of the system are uploaded to an upper computer in real time for charging, analysis, decision-making and the like.

A second part: the vehicle detection algorithm based on the geomagnetic sensor comprises three parts, namely signal preprocessing, feature extraction and multi-feature fusion judgment. As shown in fig. 5, the vehicle detection process includes the steps of:

s1, acquiring geomagnetic field component values in X-axis and Y-axis directions through a first geomagnetic sensor group and a second geomagnetic sensor group, and calculating geomagnetic field information of a parking space;

s2, extracting features according to the geomagnetic field information to obtain a target feature group;

and S3, performing multi-feature fusion judgment according to the target feature group to obtain a vehicle detection result.

Specifically, in this embodiment, let BX1 and BY1 be the geomagnetic field component values in the X and Y axis directions output BY the first geomagnetic sensor group; BX2 and BY2 are geomagnetic field component values in the X and Y axis directions output BY the second geomagnetic sensor group, so that the geomagnetic field related quantities at the parking space can be calculated as follows:

first order difference of geomagnetic measurement values in the X direction:

DiffX＝BX1-BX2 (1)

first order difference of geomagnetic measurement values in Y direction:

DiffY＝BY1-BY2 (2)

the system error of the first-order difference in the X direction is a first-order difference initial value when the parking space is free of vehicles:

SystemX＝DiffX (3)

the system error of the first-order difference in the Y direction is a first-order difference initial value when the parking space is free of the vehicle:

SystemY＝DiffY (4)

deviation of first order difference of geomagnetic measurement values in X direction:

deltX＝DiffX-SystemX (5)

deviation of first order difference of geomagnetic measurement values in Y direction:

deltY＝DiffY-SystemY (6)

sum of deviations of first order differences of the geomagnetic measurement values in the X and Y directions:

deltXY＝deltX+deltY (7)

according to equation (3), the first difference of the geomagnetic vector direction angles in the XY plane:

the variation of the Y component value BY2 of the geomagnetic field measured BY the second geomagnetic sensor group:

deltBY2＝BY2-SystemBY2 (9)

(1) Signal pre-processing

The sensor unit and a control system thereof are fixed in the sleeve and are arranged at the geometric center of the roadside parking space with the burial depth of 5-15cm. After the system is started, a strong geomagnetic threshold is set, when an X or Y component value BX (BY) measured BY a sensor exceeds the threshold, a non-target vehicle is determined to pass through, and the system waits for a certain time, namely waits for the non-target vehicle to leave. Secondly, under the condition that no vehicle exists in the parking space, X, Y and Z component values BX, BY and BZ of the geomagnetic field are measured in a plurality of cycles, and at the moment, the measured values comprise a basic value B of the geomagnetic field _E Interference signal B influenced by parking space surrounding environment _N The system average value of the vehicle-absent state of the Y component value BY2 of the geomagnetic field measured BY the second geomagnetic sensor group is:

wherein n is the number of measurement cycles, determining SystemX (i) and SystemY (i) of each cycle according to the formulas (1) to (4), and the final system error of the first-order difference in the X and Y directions is as follows:

(2) Feature extraction

The sensors measure geomagnetic signal X, Y component values BX, BY, and deviations deltX, deltY of the first order difference of geomagnetic measurement values in X, Y directions are calculated according to equations (5) - (6), the deviations deltX, deltY reflect the abnormal change of the geomagnetic field caused BY the vehicle entering the parking space, and deltXY is further calculated according to equation (7). Meanwhile, the geomagnetic vector direction angles of the two groups of sensors in the XY plane are calculated according to the formula (8), and a first-order difference diffA of the geomagnetic vector direction angles in the XY plane is obtained. The amount of change in the Y component value BY2 of the geomagnetic field measured BY the second geomagnetic sensor group is calculated according to equation (9).

(3) Multi-feature fusion judgment

And judging whether the vehicle drives in or not in the parking space without occupying the vehicle, and adopting a plurality of different characteristics to independently judge. And fusing the multiple judgment results to give a judgment result. And judging whether the vehicle is driven away or not in the parking space occupied state, adopting a plurality of different characteristics, independently judging, fusing a plurality of judgment results and giving a judgment result. The specific process is described as follows.

After the system is initialized, in the parking space, under the state of no vehicle:

firstly, according to deltXY, if deltXY >25, determining geomagnetic aberration, and judging that the vehicle enters the parking space for the first time;

secondly, according to diffA, if diffA is greater than 0.2, the geomagnetic value is determined to be abnormal, and the vehicle is determined to enter;

thirdly, if the deltBY2 is more than or equal to 30, judging that the vehicle enters the parking space again;

and finally, if deltX is larger than or equal to K, or deltY is larger than or equal to K, or deltX is smaller than or equal to-K, or deltY is smaller than or equal to-K (the K value is a threshold value determined according to the installation place of the system), finally judging that the vehicle enters the parking space, and adjusting the vehicle state of the parking space to be the vehicle occupation state.

In a state where it has been determined that the vehicle occupies the space:

according to the three characteristics of deltX, deltY and deltBY2, if-10 is less than or equal to deltX and less than or equal to 10, and-10 is less than or equal to deltY and less than or equal to 10, and deltBY2 is less than or equal to 30, the system determines that the vehicle is driven out, and the system restores the state without the vehicle occupation.

In summary, compared with the prior art, the invention has the following advantages:

(1) The single geomagnetic detection mode has extremely low power consumption, and batteries do not need to be replaced for a long time, theoretically, the batteries of the sensor units buried under the ground and the control systems thereof do not need to be replaced for 8 to 10 years;

(2) The single geomagnetic detection mode has the advantages of low sensor unit cost and low failure rate, and reduces the maintenance cost of the sensor unit.

(3) The accuracy of the vehicle detection result in the parking space is improved.

In alternative embodiments, the functions/acts noted in the block diagrams may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Furthermore, the embodiments presented and described in the flow charts of the present invention are provided by way of example in order to provide a more thorough understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed, and in which sub-operations described as part of larger operations are performed independently.

Furthermore, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise indicated to the contrary, one or more of the described functions and/or features may be integrated in a single physical device and/or software module, or one or more functions and/or features may be implemented in separate physical devices or software modules. It will also be understood that a detailed discussion of the actual implementation of each module is not necessary for an understanding of the present invention. Rather, the actual implementation of the various functional modules in the apparatus disclosed herein will be understood within the ordinary skill of an engineer, given the nature, function, and internal relationship of the modules. Accordingly, those skilled in the art can, using ordinary skill, practice the invention as set forth in the claims without undue experimentation. It is also to be understood that the specific concepts disclosed are merely illustrative of and not intended to limit the scope of the invention, which is defined by the appended claims and their full scope of equivalents.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention or a part thereof which substantially contributes to the prior art may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The logic and/or steps represented in the flowcharts or otherwise described herein, such as an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Further, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.

It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A multi-feature fusion vehicle detection method based on a geomagnetic sensor is characterized by comprising the following steps:

2. The method for detecting a vehicle based on multi-feature fusion of geomagnetic sensors according to claim 1, wherein the obtaining geomagnetic component values in X-axis and Y-axis directions by the first geomagnetic sensor group and the second geomagnetic sensor group to calculate geomagnetic information of the parking space comprises:

calculating the XY plane geomagnetic vector direction angle measured by the first geomagnetic sensor group according to the X axis magnetic field component value output by the first geomagnetic sensor group and the Y axis magnetic field component value output by the first geomagnetic sensor group;

3. The geomagnetic sensor-based multi-feature fusion vehicle detection method according to claim 1, further comprising a step of performing signal preprocessing according to the geomagnetic field information, wherein the step of performing signal preprocessing comprises:

4. The geomagnetic-sensor-based multi-feature fusion vehicle detection method according to claim 2, wherein the performing feature extraction according to the geomagnetic field information to obtain a target feature group comprises:

acquiring geomagnetic vector direction angles of an XY plane according to the first geomagnetic sensor group and the second geomagnetic sensor group, and determining a first-order difference of the geomagnetic vector direction angles of the XY plane;

acquiring geomagnetic field component values in the Y-axis direction according to the second geomagnetic sensor group, and determining the deviation of the geomagnetic field component values in the Y-axis;

5. The method for detecting the vehicle based on the geomagnetic sensor and the multi-feature fusion as recited in claim 2, wherein the performing the multi-feature fusion judgment according to the target feature group to obtain the vehicle detection result comprises:

6. The method as claimed in claim 5, wherein the step of determining whether the vehicle enters the parking space by using a plurality of different features and fusing a plurality of determination results to obtain a determination result comprises:

finally, if the deviation of the first order difference of the geomagnetic measurement value in the X direction is greater than or equal to a positive threshold value, or the deviation of the first order difference of the geomagnetic measurement value in the Y direction is greater than or equal to a positive threshold value, or the deviation of the first order difference of the geomagnetic measurement value in the X direction is less than or equal to a negative threshold value, or the deviation of the first order difference of the geomagnetic measurement value in the Y direction is less than or equal to a negative threshold value, the vehicle is finally judged to enter the parking space, and the vehicle state of the parking space is adjusted to be the vehicle occupation state.

7. The method as claimed in claim 5, wherein the step of determining whether the vehicle is away by using a plurality of different features in a parking space occupied by the vehicle, and fusing the determination results to obtain the determination result comprises:

and when the value of the deviation of the first order difference of the geomagnetic measurement values in the X direction is [ -10,10], the value of the deviation of the first order difference of the geomagnetic measurement values in the Y direction is [ -10,10], and the value of the deviation of the Y-axis magnetic field component values output by the second geomagnetic sensor is less than or equal to 30, determining that the vehicle has driven out, and adjusting the vehicle state of the parking space to a vehicle unoccupied state.

8. The utility model provides a multi-feature fuses vehicle detection device based on earth magnetism sensor which characterized in that includes:

and the third module is used for performing multi-feature fusion judgment according to the target feature group to obtain a vehicle detection result.

9. An electronic device comprising a processor and a memory;

the memory is used for storing programs;

the processor executing the program realizes the method of any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that the storage medium stores a program, which is executed by a processor to implement the method according to any one of claims 1 to 7.