WO2016086399A1

WO2016086399A1 - Beacon-based visual positioning system and method

Info

Publication number: WO2016086399A1
Application number: PCT/CN2014/093087
Authority: WO
Inventors: 覃政
Original assignee: 覃政
Priority date: 2014-12-05
Filing date: 2014-12-05
Publication date: 2016-06-09

Abstract

Disclosed in the present invention is a beacon-based visual positioning system, comprising: a signal transmission module, a plurality of beacon modules for numbering, an image acquisition module and an image processing module. The signal transmission module is for transmitting at least one set of continuous control signals to control light-on or light-off state of each beacon module; the beacon module comprises a signal receiving unit and an indicator light; the image acquisition module comprises a signal synchronizing unit and a camera unit; the image processing module acquires at least three light-off beacon modules in an image sequence acquired by the image acquisition module, the light-off beacon modules not being on the same straight line, and controls a signal time to determine a number of the beacon modules, so as to obtain a position coordinate of a beacon unit, and calculate a position of the camera unit according to the position coordinate of the beacon module.

Description

Beacon-based visual positioning system and method

Technical field

The invention relates to a visual positioning system and method, in particular to a beacon-based visual positioning system and method.

Background technique

In general, in the field of computer vision, especially in the field of augmented reality, image analysis of environmental beacons can locate relative position and attitude information of image acquisition devices (such as cameras).

At present, the beacon system mainly used is a constant-light beacon system, which does not distinguish between beacons and uses an exhaustive method for calculation. When the number of beacons appearing in the same picture is too large, the computational complexity increases and rapid recognition cannot be achieved. There is also a beacon system in which the beacon is in the form of a two-dimensional code, but its computational complexity is still too large for portable devices such as head-mounted devices. In addition, there is a beacon system that uses binary strobe mode, but when the number of beacons is too large (more than 100) and the binary code is too long (more than 7 bits), it is difficult to continuously track acquisition during fast motion. It is easy to cause the failure of identifying beacons.

Based on the above-mentioned deficiencies of the prior art, it is therefore necessary to develop a beacon system capable of quickly identifying a large number of beacons.

Summary of the invention

It is an object of the present invention to provide a beacon-based visual positioning system comprising a signal transmission module, a plurality of numbered beacon modules, an image acquisition module and an image processing module, wherein the signal transmission module is configured to transmit at least one continuous group Control signal to control the on/off state of each beacon module; the beacon module includes a signal receiving unit and an indicator light; the signal receiving unit is configured to receive a control signal from the signal transmitting module to control the indicator light to be turned off or Controlling the blinking of the indicator light by controlling a clock module inside the signal unit; each numbered beacon module corresponds to a unique position coordinate; the image acquisition module includes a signal synchronization unit and an imaging unit, and the synchronization unit is used for Receiving control issued by the signal transmitting module a signal, the image capturing unit synchronously captures an image sequence of the beacon module according to a frequency of the control signal received by the synchronization unit; and the image processing module acquires at least three of the image sequences captured by the image capturing module The beacon module not in a straight line determines the number of the beacon module by controlling the signal time to obtain the position coordinates of the beacon unit, and calculates the camera according to the position coordinates of the beacon module The location of the unit.

Preferably, the signal receiving unit and the synchronization unit each have a built-in clock module, and the signal transmitting module issues a control signal to simultaneously activate the clock module and control the blinking of the indicator light through the clock module, the camera unit The image sequence of the beacon module is synchronously captured according to the frequency of the clock module.

Preferably, the indicator lights of the plurality of beacon modules are divided into groups, and each group emits light of different wavelength bands.

Preferably, the indicator lights of the different bands emit one or more of white light, blue light, green light, red light, and infrared light.

Preferably, the indicator lights of the beacon modules located in different groups are simultaneously turned off by the same control signal.

Preferably, the light-off signal of the indicator light is a square wave pulse signal.

Preferably, the light-off signal of the square wave indicator light is one of a positive single pulse, a positive double pulse, a negative single pulse and a negative double pulse.

Preferably, the camera unit comprises two parallel cameras with a pitch of 50-100 mm.

Preferably, the beacon module has a flat cylindrical shape, and a hemispherical protrusion at the center of the top surface of the cylinder is the beacon indicator light.

According to another aspect of the present invention, there is provided a positioning method using the above-described visual positioning system, the positioning steps of which are as follows: a) uniformly arranging the beacon modules in a space requiring positioning, for each of the beacon modules Numbering, recording a unique position coordinate corresponding to each of the beacon modules; b) the signal transmitting module sends a different control signal, and the synchronization unit and the beacon module in the image capturing module synchronously receive the control signal, The image capturing unit synchronously captures an image sequence of the beacon module according to the received control signal frequency or the clock module frequency; c) the image processing module identifies, according to the collected image sequence, at least the lights in the image at different times The three positions are not on the same line of the beacon module; d) by pulse time The number of the identified beacon module is determined to obtain the position coordinates of the beacon unit, and the position of the camera unit is calculated according to the position coordinates of the beacon module.

The beacon-based visual positioning system and method of the invention has a fast beacon recognition function, especially for a large number of beacon systems, which can better reflect the advantages of the visual positioning system of the invention in recognition speed, and at the same time, The amount of computation is small and reliable compared to other beacon recognition systems.

It is to be understood that the foregoing general descriptions

DRAWINGS

Further objects, features, and advantages of the present invention will be made apparent by the following description of the embodiments of the invention.

1(a) and 1(b) are schematic diagrams showing the system architecture of the visual positioning system of the present invention;

Figure 2 shows schematically four different control signal diagrams;

FIG. 3 shows a schematic diagram of a specific application in the embodiment of the present invention.

detailed description

Objects and functions of the present invention, and methods for achieving the objects and functions will be clarified by referring to the exemplary embodiments. However, the invention is not limited to the exemplary embodiments disclosed below; it can be implemented in various forms. The essence of the description is merely to assist those skilled in the relevant art to understand the specific details of the invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the figures, the same reference numerals are used to refer to the same or similar parts, or the same or similar steps.

The present invention provides a beacon-based visual positioning system for determining the position of an image acquisition device in space by acquiring an image and analyzing the distribution characteristics of the beacon in the image.

1(a) and 1(b) are diagrams showing the architecture of a beacon-based visual positioning system in accordance with the present invention. The visual positioning system 100 of the present invention includes a plurality of beacon modules 101, a signal transmitting module 102, an image capturing module 103, and an image processing module 104.

The beacon module 101 is configured to identify location coordinates in the space. According to a preferred embodiment of the invention, a plurality of beacon modules 101 are arranged uniformly in space and adjacent to each other at equal intervals, Each beacon module 101 corresponds to a position coordinate, and a plurality of position coordinates constitute a space, and all beacon module 101 position information also constitutes a position coordinate table. According to the invention, at least three beacon modules 101 can be used to locate a location. The beacon module 101 as a whole presents a flat cylindrical body, the hemispherical projection at the center of the top surface of the cylinder is the beacon indicator 101b, and the signal receiving unit 101a is located at the bottom of the cylinder. Preferably, the cylinder has a diameter of about 8 to 10 cm and a height of 5 to 8 cm, and the overall volume is small for easy arrangement.

Preferably, the on/off signal of the beacon indicator 101b, that is, the lighting time and the extinction time, is presented as a pulse signal having a certain pulse width. As shown in FIG. 2, FIG. 2(a) and FIG. 2(b) are positive single pulse and positive double pulse, and FIG. 2(c) and FIG. 2(d) are negative single pulse and negative double pulse. The single pulse signal differs from the double pulse signal in the number of times the beacon indicator 101b is continuously turned off. More preferably, in order to increase the recognition degree of the control signal and prevent misjudgment, the blinking signal of the beacon indicator 101b should use a double pulse square wave signal, so that the beacon indicator 101b is continuously turned off twice. Finally, it should be understood that the blinking signal of the beacon indicator 101b that can be used in the present invention is not limited to the above four square wave signals.

In addition, if the positioning space is required to be large, the beacon module 101 that emits a single band of light is difficult to meet the positioning requirement, and in order to improve the positioning accuracy, a multi-band multi-group beacon system, such as blue light and green light, may be set. The beacon module 101 of the four bands of red light and infrared light, the beacon module 101 of each band is composed of one group, and the four bands are four sets of beacon systems.

The signal transmitting device 102 is configured to transmit at least one set of continuous control signals to control the on and off states of the respective beacon modules 101. Each beacon module 101 includes a signal receiving unit 101a and a beacon indicator 101b, wherein the signal receiving unit 101a is configured to receive a control signal sent by the signal transmitting module 102, wherein the control method may be selected, for example, from the following two types:

(1) The above control signal is directly used to control the on/off of the beacon indicator 101b. If the received control signal is the control on signal of the current beacon indicator 101b, the beacon indicator 101b is extinguished, otherwise it remains Lights up.

(2) The above control signal is used to activate the clock module inside the signal receiving unit 101a first, and control the blinking of the beacon indicator 101b through the clock module. After the clock module inside the signal receiving unit 101a is activated, counting starts, and it is judged whether the counted value is consistent with the current beacon module 101, and if not, the indicator 101b of the current beacon module 101 is extinguished, and vice versa.

One set of control signals corresponds to a set of beacon systems, and each beacon module 101 in a set of beacon systems corresponds to different control signals, that is, the control signals are triggered to be extinguished by different time points. According to an embodiment, the control signals between the plurality of sets of beacon systems may also be the same. For example, the beacon modules 101 of the four bands of blue, green, red, and infrared light are respectively in different beacon systems. Preferably, the control signals corresponding to the four beacon modules 101 may be the same, except that their bands and the rendered colors are different, so that the beacon module 101 can be distinguished by recognizing the colors. By using beacon signals of different colors but being triggered at the same time, a plurality of different color beacon modules 101 can be triggered at the same time, thereby greatly improving the speed of positioning recognition.

The image acquisition module 103 is configured to synchronously receive the control signal and continuously acquire the image. The image acquisition module 103 includes a signal synchronization unit 103a and an imaging unit 103b.

The signal synchronizing unit 103a is also used for receiving the control signal sent by the signal transmitting module 102, and the control signal directly controls the signal synchronizing unit 103a, and is synchronous with the time when the signal receiving unit 101a in the beacon module 101 receives the control signal, and further can be The received control signal determines which number of beacon modules 101 are off at this time. Similarly, the signal synchronizing unit 103a can also activate the internal clock module by the control signal and count it in synchronization with the clock module provided inside the beacon indicator 101b, thereby achieving the same effect as the control information direct control signal synchronizing unit 103a.

The image capturing unit 103b is configured to continuously collect images, and each of the captured images is recorded by the signal synchronization unit 103a, which is a beacon module 101 that is turned off when shooting, and the LED beacon module 101 is obtained according to the synchronized pulse time. Numbering. The image capturing unit 103b captures at least three images of the light-off beacon module 101 to meet the visual positioning requirement, and the more the light-off beacon module 101 in the image, the more accurate the visual positioning is. Preferably, the camera unit 103b is composed of two parallel cameras having a distance of 50 to 100 mm, and at least the beacon module 101 of the five distance segments in the user's field of view can be distinguished.

For a system with only one set of beacons, only one beacon module 101 may be turned off in a certain frame image captured by the image acquisition module 103. For a plurality of sets of beacon systems, there may be multiple different colors in the captured image. The beacon module 101 is simultaneously turned off. Finally, the acquired image and the signal module 101 number information corresponding to the lighted off are transmitted to the image processing module 104 for subsequent analysis.

The image processing module 104 is configured to analyze a light-off condition in an image, including turning off the light The number and color of the signal module 101, and the signal module 101 number corresponding to the image is calculated according to the analysis result, and then the actual position of the shooting position (ie, the position where the camera unit 103b is located) is calculated by looking up the position coordinate table of the beacon module 101. coordinate. Specifically, first, the image processing module 104 analyzes information such as the number of lights-off points (ie, the beacon indicator lights 101b) in the captured image, the color, the position of the light-off point in the image, and the spacing between the images, as long as there are three The light-off point is photographed to perform visual positioning; and then the position of the image capturing unit 103b at the time of shooting is calculated according to the beacon module 101 number corresponding to the light-off point and the beacon module 101 position coordinate table.

The above is a description of the module functions of the system of the present invention. Preferably, the functions of the signal transmitting module 102 and the signal synchronizing unit 103a can be integrated and added to the image capturing module 103, thereby improving the integration of the system 100 of the present invention. degree. FIG. 3 illustrates a specific application embodiment of the system 100 of the present invention. In this embodiment, the image capturing unit 103 and the image processing unit 104 are located on the wearing device of the user, and the user wears the wearing device to enter a plurality of beacon modules 101 and a signal transmitting module. In the room of 102, the position of the user can be visually located.

A plurality of sets of beacon modules 101 are arranged in the room. In this embodiment, three sets of beacon modules 101 of blue light, green light and red light are used, and each set has 20 beacon modules, and each beacon module has a number (number 1~). 60) and the corresponding position coordinates x, y, z values. In addition, the surrounding wall and ceiling area of the room is 90 square meters, and it can be calculated that there is a beacon module 101 on average 1.5 square meters (assuming that the beacon module 101 in the room is evenly arranged).

The signal transmitting module 102 transmits a control signal, and a total of 20 sets of control signals, each of which corresponds to three beacon modules 101, which are respectively a blue beacon module 101, a green beacon module 101, and a red beacon module. The pulse width of the beacon indicator 101b is 0.2 seconds, the pulse transmission time interval Δt is 0.1 second, and one cycle takes 2 seconds, and the sleep time is 0 seconds.

The control signal transmitted by the signal transmitting module 102 is simultaneously received by the image capturing module 103 and all the beacon modules 101, so that the time of the beacon module 101 and the image capturing module 103 is synchronized, and of course, the internal clock module can also be activated by The mode is synchronized in time, and the synchronization in time can be used to obtain which number of beacon modules 101 are in the off state when the image sequence is captured.

Preferably, the image capturing unit 103b captures a large angle of view lens (for example, a wide-angle lens), and assumes that the camera unit 103b simultaneously captures 30 beacon modules 101, if three The group beacon modules 101 are evenly arranged, and at least 10 beacon modules in each group of beacon modules 101 are captured. Assuming that the control signals corresponding to the 10 beacon modules 101 are evenly distributed in a period of 2 seconds, at least one beacon module 101 can be collected within 0.2 seconds, so that at least 3 can be collected at any time. The off-beacon beacon module 101 also satisfies the basic requirements of visual positioning.

The image processing unit 104 can calculate the line of sight direction of the user and the beacon module by acquiring the spacing between the at least three off-light beacon modules 101 in the captured image and the position coordinate table of the off-light beacon module 101 in the comparison image. The distance between the 101s thus completes the visual positioning of the user in the room. For example, if the connection between the three off-light beacon modules 101 is an equilateral triangle, the user is located directly in front of the three off-light beacon modules 101, and the distance between the three off-light beacon modules 101 is more If the distance between the three off-light beacon modules 101 is the same, the user is not directly opposite if the connection between the three off-beacon modules 101 is not an equilateral triangle. Looking at the three off-light beacon modules 101, there is a certain viewing angle that can be determined by measuring the different spacing between the three off-light beacon modules 101.

According to another embodiment of the present invention, the image pickup unit 103b employs two parallel cameras composed of a distance of 50 to 100 mm to acquire an image. Although the embodiment increases the amount of calculation by the image processing unit 101, the camera unit 103b employing the dual camera can distinguish five distance segments in the user's field of view. Therefore, the arrangement of the beacon module 101 is still performed in accordance with the situation in the above embodiment, except that three different sets of beacon modules 101 are replaced with three sets of identical beacon modules 101. According to the above analysis, it can be seen that the imaging unit 103b can collect the first three off-light beacon modules 101 after 0.2 seconds, and the three beacon points have a probability of about 70% distributed over two (inclusive) different distance segments. Therefore, at least two beacon modules 101 can be distinguished, and the other beacon module 101 is suspected. Therefore, only three times the calculation amount can be added, and the acquisition of the beacon module 101 can be realized, and the present invention is further displayed. Fast recognition performance for a large number of beacon modules.

In summary, a beacon-based visual positioning system and method of the present invention has a fast beacon recognition function, and particularly for a large number of beacon systems, the advantages of the visual positioning system of the present invention in recognition speed are more apparent, and At the same time, the amount of computation required is small, and it has reliable stability compared to other beacon recognition systems.

The drawings are only schematic and are not drawn to scale. Although combined with a preferred implementation The invention has been described by way of example, but it should be understood that the scope of the invention is not limited to the embodiments described herein.

Other embodiments of the invention will be apparent to those skilled in the <RTIgt; The description and the examples are to be considered as illustrative only, and the true scope and spirit of the invention are defined by the claims.

Claims

A beacon-based visual positioning system, comprising a signal transmitting module, a plurality of numbered beacon modules, an image collecting module and an image processing module, wherein

The signal transmitting module is configured to transmit at least one continuous control signal to control a light-off state of each of the beacon modules;

The beacon module includes a signal receiving unit and an indicator light, and the signal receiving unit is configured to receive a control signal sent by the signal transmitting module to control the indicator light to be turned off or to control the indication by controlling a clock module inside the signal unit. Lights are off; each numbered beacon module corresponds to a unique position coordinate;

The image acquisition module includes a signal synchronization unit and an imaging unit, the synchronization unit is configured to receive a control signal sent by the signal transmission module, and the imaging unit synchronously captures the frequency according to a frequency of the control signal received by the synchronization unit. Image sequence of the beacon module;

The image processing module obtains the number of the beacon module by controlling the signal time by acquiring at least three beacon modules in the image sequence captured by the image acquisition module and not in a straight line. The position coordinates of the beacon unit, and the position of the camera unit is calculated according to the position coordinates of the beacon module.
The visual positioning system according to claim 1, wherein said signal receiving unit and said synchronizing unit each have a clock module built therein, said signal transmitting module issuing a control signal while activating said clock module and passing said clock The module controls the indicator light to be off, and the camera unit synchronously captures the image sequence of the beacon module according to the frequency of the clock module.
The visual positioning system according to claim 1, wherein the indicator lights of the plurality of beacon modules are divided into groups, and each group emits light of different wavelength bands.
The visual positioning system according to claim 3, wherein the indicator light of the different wavelength bands emits one or more of white light, blue light, green light, red light, and infrared light.
The visual positioning system according to claim 3, wherein the indicator lights of the beacon modules located in different groups are simultaneously turned off by the same control signal.
The visual positioning system of claim 1 wherein: said indicator light The light-off signal is a square wave pulse signal.
The visual positioning system according to claim 6, wherein the bright-on signal of the square wave indicator is one of a positive single pulse, a positive double pulse, a negative single pulse, and a negative double pulse.
The visual positioning system according to claim 1, wherein said imaging unit comprises two parallel cameras with a pitch of 50 to 100 mm.
The visual positioning system according to claim 1, wherein the beacon module has a flat cylindrical shape, and the hemispherical projection at the center of the top surface of the cylinder is the beacon indicator light.
A positioning method using the visual positioning system of claim 1, the positioning steps are as follows:

a) uniformly arranging the beacon modules in a space in which positioning is required, and for each beacon module number, recording a unique position coordinate corresponding to each of the beacon modules;

b) the signal transmitting module sends different control signals, the synchronization unit in the image acquisition module and the beacon module synchronously receive the control signal, and the camera unit synchronously shoots according to the received control signal frequency or the clock module frequency. An image sequence of the beacon module;

c) the image processing module identifies, according to the collected image sequence, the beacon module that at least three positions of the image that are off at different times are not on the same straight line;

d) determining the number of the identified beacon module by the pulse time to obtain the position coordinates of the beacon unit, and calculating the position of the camera unit according to the position coordinates of the beacon module.