Pseudo light source identification method based on light source design in visible light positioning

Abstract

The invention discloses a light source design-based false light source identification method in visible light positioning, and belongs to the technical field of navigation positioning. A plurality of light sources with different radiuses are adopted as a group of light source arrays, the light sources are circularly arranged clockwise or anticlockwise to form a polygonal dot matrix, and the size sequence relation of each sub-light source in each group of light sources according to clockwise or anticlockwise sorting is recorded; in the receiving process, after the light source ID is confirmed by identifying the feature sequence point light source, whether the clockwise or anticlockwise arrangement sequence of the sub-light sources in the light source array is consistent with the preset recorded arrangement sequence is analyzed to judge the authenticity of the light source; if the arrangement relation of the neutron light sources in the light source array is consistent with that during installation, determining that the light source is a real light source; otherwise, judging the light source as a mirror image light source. IDs between the sub light sources do not need to be distinguished by stripes, the identification can be carried out according to the arrangement sequence of the sub light sources in each group of light source array, the identification method is simple and easy to calculate, the identification precision and speed are improved, the identification can be effectively carried out, and the light source design is simple.

Description

Technical Field

[0001] The invention belongs to the technical field of navigation and positioning, and relates to a visible light authentication technology, and in particular to a pseudo light source authentication method based on light source design in visible light indoor positioning. Background Art

[0002] Visible light positioning (VLP) has become an indoor positioning technology with broad application prospects due to its low cost, centimeter-level high accuracy, and the advantages of not requiring additional complex and expensive equipment. VLP achieves positioning by emitting a coded light signal containing a location ID through a light source. However, in indoor environments, objects with reflective properties such as mirrors, glass, and smooth furniture will cause the light source to reflect and form a pseudo light source that cannot be used for positioning. If the positioning system mistakenly identifies the pseudo light source as a valid light source, it will cause errors in the positioning result or even invalidity.

[0003] Prior art document 1 "An anti-interference method based on the rotation characteristics of light source array in visible light positioning" proposes an anti-interference method based on the rotation characteristics of light source array, which uses light source array instead of point light source, and first identifies the stripes of each sub-light source in each light source array through the receiving end, distinguishes the ID between sub-light sources through the stripes, and then compares with the preset light source ID rotation order, which can effectively distinguish the real light source from the false light source caused by reflection. However, the algorithm is complex and has recognition errors. Summary of the invention

[0004] In order to overcome the defects of the prior art, the present invention invents a pseudo-light source identification method based on light source design to achieve high-precision and high-speed identification of real light sources and mirror light sources. Compared with the existing pseudo-light source identification method, the advantage of the present invention is that it does not need to use stripes to distinguish the IDs between sub-light sources, the identification method is simple and easy to calculate, and the accuracy and speed of identification are improved.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A pseudo-light source identification method based on light source design in visible light positioning, the pseudo-light source identification method uses multiple light sources with different radii as a group of light source arrays, and the multiple light sources are arranged in a polygonal dot matrix in a clockwise or counterclockwise cycle. After the arrangement is completed, the size order relationship of each sub-light source in each group of light sources is recorded in a clockwise or counterclockwise order; in the receiving process, after confirming the light source ID by identifying the characteristic sequence point light source, the authenticity of the light source is judged by analyzing whether the clockwise or counterclockwise arrangement order of the sub-light sources in the light source array is consistent with the preset recorded arrangement order. If the arrangement relationship of the sub-light sources in the light source array is consistent with that at the time of installation, the light source is considered to be a valid light source; otherwise, the light source is regarded as a pseudo-light source caused by reflection and is not brought into the positioning solution process. The pseudo-light source identification method includes two parts: installation and receiving, and specifically includes the following steps:

[0007] The installation part is as follows:

[0008] Step 1: When installing the light source, use a light source array to replace a single point light source. The light source array consists of multiple point light sources with different diameters. The number of point light sources is set according to actual needs and must be greater than two.

[0009] Sort the sub-light sources in each group of light sources by size. Assume that the diameters of the sub-light sources in each group of light sources are where i represents the i-th light source group, n i Represents the number of sub-light sources in the i-th group. The diameter sequence is obtained by sorting the diameters in each group: where d′ ij is the diameter of the jth sub-light source after sorting. ij is the diameter of the jth sub-light source after sorting, where i represents the i-th group of light sources.

[0010] For the i-th group of light sources, select the k-th sub-light source from the sorted diameter sequence, denoted as: d i,k =d′ ik , where k is the position of the selected sub-light source in the sorted sequence, and the selected k is consistent in all groups; the light source with the largest size is expressed as: in Represents the maximum diameter of the light sources in the i-th group.

[0011] At the transmitting end, the PN sequence containing the positioning information is modulated onto the light source according to actual needs. The light source emits the PN sequence at a high-speed flashing frequency that is imperceptible to the human eye. The bright light represents "1" in the sequence, and the dark light represents "0" in the sequence. According to the communication requirement of large amount of information, each group of light sources with the largest diameter, i.e., d max,i The maximum length of the PN transmission sequence is used as the communication sequence light source; the kth light source of each group of light sources is uniformly selected, that is, di,k As a characteristic sequence light source, a PN transmission sequence of a specific length is given to quickly identify the light group ID; the remaining permanently on lights do not require a transmission sequence and rely on current flow to provide lighting.

[0012] Step 2: Arrange the sub-light sources in each light source array into a polygonal dot matrix in a clockwise or counterclockwise order. Record the order of the size of the sub-light sources in each light source array in a clockwise or counterclockwise order.

[0013] The receiving part is as follows:

[0014] Step 1: The receiving end uses a camera with a scanning frequency greater than the flickering frequency of the light source to aim at the light source for shooting.

[0015] Step 2: The receiving end receives the kth light source d preset in the image i,k Decode and determine the light source ID number, and confirm the arrangement order of the light source sequence shape according to the ID.

[0016] Step 3: Check whether the light source array sequence in the camera is consistent with the light source shape arrangement sequence confirmed by ID in step 2: If it matches the sequence preset during installation, it is determined to be a real light source and can be brought into the positioning and solving process. Otherwise, it is determined to be a mirror light source and is not brought into the positioning and solving process.

[0017] Compared with the existing visible light counterfeit detection technology, the beneficial effects of the present invention are:

[0018] The present invention does not need to use stripes to distinguish the IDs between sub-light sources, and can identify counterfeits according to the arrangement order of sub-light sources in each light source array. The identification method is simple and easy to calculate, which improves the accuracy and speed of identification, can effectively identify counterfeits, and the light source design is simple and easy to modify. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the arrangement of the i-th group of light sources and the principle of light source mirroring. 1, 2, and 3 are designed real light sources with different diameters. Light source 1 is used for communication, light source 2 is used as a characteristic sequence light source to facilitate identification of the light group ID, and light source 3 is used for lighting; 1', 2', and 3' represent pseudo light sources for mirror imaging; a is a mirror. DETAILED DESCRIPTION

[0020] The method for detecting fake light sources based on light source design in visible light positioning includes two parts: installation and receiving, and specifically includes the following steps:

[0021] The installation part is as follows:

[0022] Step 1: When installing the light source, use a light source array to replace a single point light source. The light source array consists of multiple point light sources with different diameters, such as Figure 1As shown in the figure, three point light sources are used. Light sources 1, 2, and 3 are designed real light sources with different diameters, and light sources 1', 2', and 3' are pseudo light sources for mirror imaging. The diameters of the 1, 2, and 3 photon light sources are d i1 , d i2 , d i3 , where i represents the i-th group of light sources, and the sub-light sources in each group of light sources are sorted according to their size. By sorting the diameters in each group, the sorted diameter sequence is obtained: d′ i3 ≤d′ i2 ≤d′ i1 , where d′ ij is the diameter of the jth sub-light source after sorting.

[0023] For the i-th group of light sources, select the second sub-light source from the sorted diameter sequence, denoted as: d i,k =d′ ik , where k is the position of the selected sub-light source in the sorted sequence, and the selected k is consistent in all groups; the light source with the largest size is expressed as: in represents the maximum diameter of the i-th group of light sources, represents the maximum diameter of the i-th group of light sources. Select k = 2, where d max,i =d 1,i .

[0024] At the transmitting end, the PN sequence containing the positioning information is modulated onto the light source according to actual needs. The light source emits the PN sequence at a high-speed flashing frequency that is imperceptible to the human eye. The bright light represents "1" in the sequence, and the dark light represents "0" in the sequence. According to the communication requirement of large amount of information, each group of light sources with the largest diameter, i.e., d 1,max The PN transmission sequence of length N = 15 is used as the communication sequence light source; the second light source of each light source group, i.e. d2, is uniformly selected. i As a characteristic sequence light source, a PN transmission sequence of length N=7 is assigned to quickly identify the light group ID; the remaining permanently on lights do not require a transmission sequence and rely on current flow to provide lighting.

[0025] Step 2: Arrange the sub-light sources in each light source array into a polygonal dot matrix in a clockwise or counterclockwise order. Record the order of the size of the sub-light sources in each light source array in a clockwise order.

[0026] The receiving part is as follows:

[0027] Step 1: The receiving end uses a mobile phone camera with a scanning frequency greater than the light source emission frequency to aim at the light source for shooting, where the camera shutter speed is 1 / 4000s and the ISO sensitivity is 600.

[0028] Step 2: After receiving, the receiving end first identifies the characteristic sequence of the light source with the second largest diameter during demodulation to distinguish different groups of light source arrays. After identifying the ID, the arrangement order of the light source sequence shape is confirmed according to the ID.

[0029] Step 3: Check whether the light source array sequence in the camera is consistent with the light source array sequence confirmed by ID in step 2: If it is consistent with the sequence preset during installation, it is determined to be a real light source and can be brought into the positioning and solving process. Otherwise, it is determined to be a mirror light source and is not brought into the positioning and solving process.

[0030] Compared with the existing visible light authentication technology, the present invention does not need to use stripes to distinguish the IDs between sub-light sources. It only needs to identify the characteristic sequence light source, and then authenticate according to the arrangement order of the sub-light sources in each group of light source arrays. The identification method is simple and easy to calculate, which improves the accuracy and speed of identification, can effectively authenticate, and the light source design is simple and easy to modify.

[0031] The above-described embodiments merely express the implementation methods of the present invention, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for detecting fake light sources based on light source design in visible light positioning, characterized in that: The pseudo-light source authentication method adopts a plurality of light sources with different radii as a group of light source arrays, and the plurality of light sources are arranged in a polygonal dot matrix in a clockwise or counterclockwise cycle. After the arrangement is completed, the size order relationship of each sub-light source in each group of light sources is recorded in a clockwise or counterclockwise order. During the receiving process, after the light source ID is confirmed by identifying the characteristic sequence point light source, the authenticity of the light source is judged by analyzing whether the clockwise or counterclockwise arrangement order of the sub-light sources in the light source array is consistent with the preset recorded arrangement order. If the arrangement relationship of the sub-light sources in the light source array is consistent with that during installation, it is determined to be a real light source; otherwise, it is determined to be a mirror light source.

2. The method for detecting fake light sources based on light source design in visible light positioning according to claim 1, characterized in that: The fake light source identification method includes two parts: installation and receiving, and includes the following steps: The installation part is as follows: Step 1: When installing the light source, a light source array is used to replace a single point light source; the light source array is composed of a plurality of point light sources with different diameters, and the number of point light sources is set according to actual needs and is greater than two; Sort the sub-light sources in each group of light sources by size; assuming that the diameters of the sub-light sources in each group of light sources are where i represents the i-th light source group, n i Represents the number of sub-light sources in the i-th group; the sorted diameter sequence is obtained by sorting the diameters in each group: where d ′ ij is the diameter of the jth sub-light source after sorting; where d ′ ij is the diameter of the jth sub-light source after sorting, where i represents the i-th group of light sources; For the i-th group of light sources, select the k-th sub-light source from the sorted diameter sequence, denoted as: d i,k =d ′ ik , where k is the position of the selected sub-light source in the sorted sequence, and the selected k is consistent in all groups; the light source with the largest size is expressed as: in represents the maximum diameter of the light source in the i-th group; At the transmitting end, the PN sequence containing the positioning information is modulated onto the light source according to actual needs. The light source transmits the PN sequence, where the bright light represents "1" in the sequence and the dark light represents "0" in the sequence. The light source with the largest diameter in each group is given a diameter of d max,i The PN transmission sequence with the maximum length is used as the communication sequence light source; the kth light source of each light source group is uniformly selected, that is, d i,k As a characteristic sequence light source, a PN transmission sequence of a specific length is given to quickly identify the light group ID; the other permanent lights do not need a transmission sequence and rely on current flow to provide lighting; Step 2: Arrange the sub-light sources in each light source array into a polygonal dot matrix in a clockwise or counterclockwise order; record the order of the sizes of the sub-light sources in each light source array in a clockwise or counterclockwise order; The receiving part is as follows: Step 1: The receiving end uses a camera with a scanning frequency greater than the flickering frequency of the light source to aim at the light source for shooting; Step 2: The receiving end receives the kth light source d preset in the image i,k Decode and determine the light source ID number, and confirm the arrangement order of the light source sequence shape according to the ID; Step 3: Check whether the light source array sequence in the camera is consistent with the light source shape arrangement sequence confirmed by the ID in step 2: If it matches the sequence preset during installation, it is determined to be a real light source and can be brought into the positioning solution process; otherwise, it is determined to be a mirror light source and is not brought into the positioning solution process.

Images