Library indoor lighting control system and method based on Internet of Things

Abstract

The present invention relates to the field of optical systems, and specifically discloses a library indoor lighting control system and method based on the Internet of Things. The system includes: a plurality of visible light emitting sub-nodes, each of which includes an emitting base, a first light source, a first polarizer, a first controller, and a first communication module. The first light source is embedded and fixed in the emitting base, the first polarizer is located above the first light source, the first polarizer is rotatably connected to the emitting base, and a first driving member for driving the first polarizer to rotate is provided in the emitting base; the first communication module is used to receive first control information, the first controller is used to generate a first control instruction according to a preset mode or the first control information, and the first driving member is used to drive the first polarizer to rotate according to the first control instruction to form flicker frequency information. The technical solution of the present invention can be combined with the characteristics of the library scene, so that users can use smart phones to perform visible light communication.

Description

Technical Field

[0001] The present invention relates to the field of optical systems, and in particular to a library indoor lighting control system and method based on the Internet of Things. Background Art

[0002] With the development of technology, lighting systems are gradually being given more functions. For example: automatic control, eye protection and even communication. As LED technology becomes the mainstream lighting technology, indoor visible light communication has gradually entered people's field of vision. Visible light communication means that LED is used as a lighting tool and also for visible light communication. The general technical logic is to load the communication coding signal on the LED driving circuit, so that the LED outputs the lighting light carrying the modulated signal for communication during the lighting process.

[0003] However, in a large indoor public place such as a library, it is necessary to ensure the lighting brightness while ensuring quietness. This will result in the need to set up light sources carrying modulation circuits in multiple locations to improve communication quality and coverage when arranging an optical communication system in a large indoor space. However, due to the limited lighting range of a single LED, if the entire lighting system works together, the communication efficiency is low.

[0004] When traditional lighting systems are transmitting data, changes in light intensity may cause visual discomfort to users, affecting user experience, especially in libraries, which are eye-intensive environments. Therefore, there is an urgent need for an IoT-based library indoor lighting control system and method that can combine the characteristics of library scenes and facilitate users to use smartphones for visible light communication. Summary of the invention

[0005] The present invention provides a library indoor lighting control system and method based on the Internet of Things, which can combine the characteristics of library scenes and facilitate users to use smart phones for visible light communication.

[0006] In order to solve the above technical problems, this application provides the following technical solutions:

[0007] The library indoor lighting control system based on the Internet of Things includes:

[0008] A plurality of visible light emitting sub-nodes, each of which includes an emitting base, a first light source, a first polarizer, a first controller and a first communication module, wherein the first light source is embedded and fixed in the emitting base, the first polarizer is located above the first light source, the first polarizer is rotatably connected to the emitting base, and a first driving member for driving the first polarizer to rotate is provided in the emitting base; the first communication module is used to receive first control information, the first controller is used to generate a first control instruction according to a preset mode or the first control information, and the first driving member is used to drive the first polarizer to rotate according to the first control instruction to form flicker frequency information;

[0009] A user terminal, wherein a second polarizer is fixed on the user terminal, and the user terminal receives light after passing through the second polarizer to obtain the flashing frequency information of the optical signal emitted by the visible light emitting sub-node;

[0010] It also includes several visible light intensity receiving sub-nodes, which include a receiving base, a photosensitive receiving module, a second controller and a second communication module. The photosensitive receiving module is embedded and fixed in the receiving base. The photosensitive receiving module is used to sense the changes in light intensity in the environment to obtain ground light intensity information, and feed it back to the second controller, and then send the ground light intensity information through the second communication module and send it to the first controller.

[0011] The basic scheme principle and beneficial effects are as follows: The library indoor lighting control system based on the Internet of Things of the present invention mainly uses visible light communication technology to realize the transmission of information. The core principle of the system is to realize the encoding and transmission of data by combining the rotation of the first polarizer with the fixed state of the second polarizer. Specifically, the system includes a number of visible light emitting sub-nodes, each of which integrates a transmitting base, a first light source, a first polarizer, a first controller and a first communication module. The first light source, usually an LED lamp, is embedded and fixed in the transmitting base, responsible for providing the light signal required for lighting and communication. The first polarizer is located above the first light source, and its position and rotation state determine the polarization direction of the emitted light signal.

[0012] The first controller generates a first control instruction according to a preset mode or the received first control information. These instructions are received through the first communication module and used to drive the first driving member, usually a stepping motor, to control the rotation of the first polarizer. The rotation speed and angle change of the first polarizer are encoded according to the information to be transmitted, thereby realizing data transmission.

[0013] The user terminal, such as a smartphone or tablet, is fixed with a second polarizer. This polarizer is fixed and is used to filter the received light signal, allowing only light with a specific polarization direction to pass through. By analyzing the flickering frequency information of the received light signal, the user terminal can decode the information transmitted by the rotation of the first polarizer.

[0014] The rotation of the first polarizer not only helps to transmit information, but also provides heat dissipation for the first light source, prolongs the service life of the light source, and reduces maintenance costs. By precisely controlling the rotation of the first polarizer, the system can achieve high-speed data transmission. This transmission method is not only fast, but also can reduce signal interference and improve communication reliability due to the directionality of the optical signal.

[0015] In summary, the present invention achieves rotation speed and angle changes of the first polarizer within a range that is imperceptible to the human eye, and users will not feel any changes in light intensity or flicker when using the library's lighting system, thereby ensuring a good reading and learning environment.

[0016] Furthermore, the first light source is an LED lamp, and the brightness of the LED lamp is adjustable.

[0017] Furthermore, the first controller is also used to automatically adjust the brightness of the first light source according to ground light intensity information.

[0018] Furthermore, the first driving member is a stepping motor, which is used to accurately control the periodic rotation of the first polarizer.

[0019] Furthermore, the first polarizer and the second polarizer are both linear polarizers.

[0020] Furthermore, the user terminal includes a photoelectric sensor for receiving and converting optical signals into electrical signals.

[0021] Furthermore, the user terminal is a smart phone.

[0022] Furthermore, the user terminal is also used to collect changes in light intensity information and use the peak value as real-time light intensity information. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a cross-sectional view of Example 1 of a library indoor lighting control system based on the Internet of Things;

[0024] Figure 2 It is a logic block diagram of Example 2 of a library indoor lighting control system based on the Internet of Things;

[0025] Figure 3 This is a schematic diagram of indoor installation of Example 2 of the library indoor lighting control system based on the Internet of Things.

[0026] The symbols in the drawings of the specification include: a visible light emitting sub-node 1, an emitting base 10, a first light source 11, a first polarizer 12, a first driving member 13, a video acquisition sub-node 2, and a visible light intensity receiving sub-node 3. DETAILED DESCRIPTION

[0027] The following is further described in detail through specific implementation methods:

[0028] Example 1

[0029] Library indoor lighting control system based on the Internet of Things (such as Figure 1 shown), including:

[0030] A plurality of visible light emitting sub-nodes 1, each of which comprises an emitting base 10, a first light source 11, a first polarizer 12, a first controller and a first communication module, wherein the first light source 11 is embedded and fixed in the emitting base 10, the first polarizer 12 is located above the first light source 11, the first polarizer 12 is rotatably connected to the emitting base 10, and a first driving member 13 for driving the first polarizer 12 to rotate is provided in the emitting base 10; the first communication module is used to receive first control information, the first controller is used to generate a first control instruction according to a preset mode or the first control information, and the first driving member 13 is used to drive the first polarizer 12 to rotate according to the first control instruction to form flicker frequency information;

[0031] A user terminal (not shown), on which a second polarizer is fixed, receives light after passing through the second polarizer, and obtains the flashing frequency information of the optical signal emitted by the visible light emitting sub-node 1;

[0032] Several visible light intensity receiving sub-nodes 3 (not shown), the visible light intensity receiving sub-nodes 3 include a receiving base, a photosensitive receiving module, a second controller and a second communication module. The photosensitive receiving module is embedded and fixed in the receiving base. The photosensitive receiving module is used to sense the change of light intensity in the environment to obtain ground light intensity information, and feed it back to the second controller, and then send the ground light intensity information through the second communication module and send it to the first controller.

[0033] When used specifically: a number of visible light emitting sub-nodes 1, each of which is responsible for lighting and communication in a specific area of ​​the library. Each visible light emitting sub-node 1 is composed of the following parts: the emitting base 10 is a fixed structure for installing and positioning the entire visible light emitting sub-node 1. The first light source 11 in this embodiment is an LED lamp, which is embedded and fixed in the emitting base 10 and is responsible for providing lighting. The first polarizer 12 is located above the first light source 11 and is installed with the emitting base 10 by a rotating connection, so that the polarizer can rotate around the axis in the base. The first driving member 13 is a stepping motor, and of course in the embodiment it can also be other driving devices that accurately control the rotation, which is built into the emitting base 10 and is used to drive the first polarizer 12 to rotate (through bearings, gears, etc.). The first controller is a microcontroller, which is used to control the first driving member 13 and generate control instructions according to a preset mode or the first control information received. The first communication module is a Bluetooth module, which is used to receive the first control information from the system central control unit and transmit the visible light communication signal to the user terminal.

[0034] The user terminal is a user's smart phone or other portable device, on which a second polarizer is fixed. The polarizer is used to filter the received light and only allow light with a specific polarization direction to pass through, thereby receiving the light signal flashing frequency information emitted by the visible light emitting subnode 1.

[0035] The visible light intensity receiving subnode 3 is used to monitor the light intensity in the library and feed it back to the central control system to achieve the purpose of automatically adjusting the lighting. The receiving base is used to install and fix the entire receiving subnode. The photosensitive receiving module is embedded and fixed in the receiving base to sense the changes in light intensity in the environment and obtain ground light intensity information. The second controller receives the light intensity information sensed by the photosensitive receiving module and generates corresponding control instructions. The second communication module sends the ground light intensity information to the first controller for lighting adjustment.

[0036] The first controller sends instructions to the first driver 13 through the first communication module according to the preset mode or the received first control information, driving the first polarizer 12 to rotate at a specific frequency, thereby changing the polarization direction and flickering frequency of the light and carrying visible light communication information. The user terminal receives the modulated light through the built-in second polarizer and decodes the flickering frequency information to achieve communication with the system. At the same time, the photosensitive receiving module monitors the light intensity in the library and feeds the information back to the second controller, which is then sent to the first controller through the second communication module to achieve automatic adjustment of the lighting intensity.

[0037] Example 2

[0038] Compared with the embodiment 1, the only difference is that it also includes a wireless communication parent node, a plurality of video acquisition child nodes 2 and a positioning server (such as Figure 2 as shown).

[0039] The wireless communication parent node (a router is selected in this embodiment) is used to receive indoor positioning and navigation request information sent by the user terminal, wherein the indoor positioning and navigation request information includes the MAC address information and the target address information of the user terminal;

[0040] Several visible light emitting subnodes 1 (three LED lights are selected in this embodiment, and the flashing frequency can of course be controlled. In this embodiment, the flashing frequencies of the three LED lights are 25Hz, 30Hz and 40Hz respectively) are installed on the roofs on the paths in the library (such as Figure 3 As shown), the range that can be illuminated by each visible light emitting sub-node 1 is divided into cells, which are used to independently send optical signals to the preset cell range according to a preset flashing frequency, wherein the preset flashing frequency is higher than 24 Hz, and the optical signals emitted by the visible light emitting sub-nodes 1 in adjacent cells do not interfere with each other in frequency, and the optical signals include the fixed position information of the visible light emitting sub-node 1;

[0041] Several visible light intensity receiving sub-nodes 3 are fixed on the ground to collect ground light intensity information in the current environment, and then send the ground light intensity information to the wireless communication parent node;

[0042] The user terminal (smartphone and / or tablet computer) is also used to collect the posture of the user terminal after sending the indoor positioning navigation request information, and after the screen posture of the user terminal is horizontally upward, collect the real-time light intensity information of the current environment and the light signal flickering frequency information emitted by the visible light emission sub-node 1, and send the real-time light intensity information and the light signal flickering frequency information to the wireless communication parent node, and then display the terminal image information through the display screen of the user terminal according to the user refresh frequency below the maximum refresh rate of the display screen (in this embodiment, it is a flicker of 50Hz), and synchronously send the user refresh frequency to the wireless communication parent node;

[0043] Several video acquisition sub-nodes 2 (in this embodiment, implemented by 3 cameras) are installed on the roof, and are used to collect environmental image information within a preset range, and identify the terminal image information in the environmental image information to obtain the identification frequency, and then identify the environmental coordinate information of the terminal image information in the environmental image information, and send the identification frequency and environmental coordinate information to the wireless communication parent node;

[0044] The positioning server (the relevant functions implemented by the local server in this embodiment) pre-stores the frequency information and fixed position information of the optical signal emitted by each visible light emitting sub-node 1, and annotates the positions of the visible light emitting sub-node 1, the visible light intensity receiving sub-node 3 and the video acquisition sub-node 2 in the pre-stored BIM model; it is used to receive the indoor positioning navigation request information, ground light intensity information, real-time light intensity information, optical signal flashing frequency information, user refresh frequency, recognition frequency and environmental coordinate information sent by the wireless communication parent node, and then uses the light propagation to receive the indoor positioning navigation request information, ground light intensity information, real-time light intensity information, optical signal flashing frequency information, user refresh frequency, recognition frequency and environmental coordinate information according to the ground light intensity information and the real-time light intensity information and the distance information between the visible light emitting sub-node 1 and the visible light intensity receiving sub-node 3. Attenuation formula is used to determine the Z-axis coordinate information of the user terminal, and then according to the matching degree of the light signal flashing frequency information, the user refresh frequency and the recognition frequency, the location information of the user terminal corresponding to the MAC address information of the recognition frequency is identified in the environmental image information, and then the X-axis coordinate information and Y-axis coordinate information of the user terminal are determined according to the location information of the user terminal in the environmental coordinate information, and then the Z-axis coordinate information, the X-axis coordinate information and the Y-axis coordinate information are processed into the current coordinate information in combination with the BIM model, and navigation path information is generated according to the current coordinate information and the target address information, and the navigation path information is sent to the user terminal through the wireless communication parent node; the user terminal is also used to display the navigation path information.

[0045] When used specifically: the user sends an indoor positioning navigation request through a smartphone or tablet. After sending the request, the user terminal collects the posture of the user terminal, and after the screen posture is horizontally upward, collects the real-time light intensity information of the current environment and the light signal flashing frequency information emitted by the visible light emission sub-node 1. This information is then sent to the wireless communication parent node. The display screen of the user terminal displays the terminal image information at a user refresh rate that does not exceed the maximum refresh rate (50Hz in this embodiment), and sends the refresh rate synchronously to the wireless communication parent node.

[0046] A router is selected as the wireless communication parent node, which is responsible for receiving indoor positioning and navigation request information from the user terminal. The request information includes the MAC address information and the target address information of the user terminal. In this embodiment, three LED lights with controllable flashing frequency are selected as visible light emitting sub-nodes 1. These sub-nodes are installed on the roof on the path in the library, and each sub-node is responsible for illuminating a specific cell. Three photosensitive sensors are set as visible light intensity receiving sub-nodes 3, which are fixed on the ground. These sub-nodes are responsible for collecting ground light intensity information in the current environment and sending the information to the wireless communication parent node. The video acquisition sub-node 2 is realized by three cameras, which are installed on the roof and are used to collect environmental image information within a preset range. The system identifies the terminal image information in the environmental image information, obtains the identification frequency, and identifies the environmental coordinate information of the terminal image information in the environmental image information. This information is sent to the wireless communication parent node.

[0047] The local server is used as the positioning server, which pre-stores the optical signal frequency information and fixed position information emitted by each visible light emitting sub-node 1, and marks the positions of these nodes in the pre-stored BIM model. The positioning server receives all relevant information from the wireless communication parent node, including indoor positioning and navigation request information, ground light intensity information, real-time light intensity information, optical signal flashing frequency information, user refresh frequency, recognition frequency and environmental coordinate information.

[0048] The positioning server determines the Z-axis coordinate information of the user terminal based on the received ground light intensity information and real-time light intensity information and the distance information between the visible light transmitting subnode 1 and the visible light intensity receiving subnode 3 using the light propagation attenuation formula. By matching the light signal flashing frequency information, user refresh frequency and recognition frequency, the server identifies the location information of the user terminal with the MAC address information corresponding to the recognition frequency in the environmental image information, and then determines the X-axis coordinate information and Y-axis coordinate information of the user terminal. The positioning server combines the Z-axis, X-axis and Y-axis coordinate information with the BIM model to process the current coordinate information, and generates navigation path information based on the current coordinate information and the target address information.

[0049] The generated navigation path information is sent to the user terminal through the wireless communication parent node, and the user terminal is responsible for displaying the navigation path information to complete the indoor navigation.

[0050] The workflow for user A to achieve indoor positioning through a smartphone is as follows:

[0051] Initiating a navigation request: User A uses his smartphone to open the indoor navigation application in the library, selects a destination, and sends an indoor positioning navigation request.

[0052] User terminal information collection: The smartphone collects the posture information of the user terminal, and after the screen posture is horizontally upward, it starts to collect the real-time light intensity information of the current environment and the flashing frequency information of the light signal emitted by the visible light emission sub-node 1.

[0053] Optical signal reception and processing: The smartphone’s sensor receives optical signals from the visible light emitting subnode 1 installed on the roof. These signals contain the subnode’s fixed position information and a preset flashing frequency (25 Hz, 30 Hz, or 40 Hz).

[0054] Information is sent to the parent node: The smartphone sends the collected real-time light intensity information, light signal flashing frequency information, and MAC address information of the user terminal to the wireless communication parent node (router).

[0055] Light intensity information collection: At the same time, the visible light intensity receiving sub-node 3 (photosensitive sensor) is fixed on the ground to collect the ground light intensity information in the current environment and send this information to the wireless communication parent node.

[0056] Video information acquisition: The video acquisition child node 2 (camera) is installed on the roof to collect environmental image information, identify the smartphone (user terminal) in the image, obtain the recognition frequency and environmental coordinate information, and then send this information to the wireless communication parent node.

[0057] Data integration and positioning calculation: The wireless communication parent node sends all collected information to the positioning server. The positioning server calculates the coordinates of the user terminal on the Z axis based on the light propagation attenuation formula, combined with the ground light intensity information, real-time light intensity information, and the distance information between the visible light transmitting sub-node 1 and the visible light intensity receiving sub-node 3.

[0058] Coordinate matching and path generation: The positioning server uses the matching degree of the light signal flashing frequency information, user refresh frequency and recognition frequency to identify the location information of the user terminal in the environmental image information and determine the X-axis and Y-axis coordinates. Then, the server processes these coordinate information into current coordinate information in combination with the BIM model and generates navigation path information.

[0059] Navigation path information transmission: The positioning server sends the generated navigation path information back to the wireless communication parent node, which is then transmitted to user A's smartphone by the parent node.

[0060] Navigation path display: After receiving the navigation path information, the smartphone displays the navigation path on the screen at the user refresh rate (50 Hz in this embodiment) to guide user A to his destination.

[0061] User navigation: User A moves in the library along the route planned by the system according to the navigation path information displayed on the smartphone until he reaches the target location.

[0062] Example 3

[0063] Compared with Example 2, the only difference is that the positioning server is also used to determine the fixed position information of the visible light emitting subnode 1 where the user terminal is located based on the light signal flashing frequency information and the pre-stored association table of the light signal flashing frequency information and fixed position information sent by the visible light emitting subnode 1, and send the fixed position information and the BIM model to the user terminal through the wireless communication parent node. The positioning server is also used to mark the fixed position information in the BIM model after determining the fixed position information of the visible light emitting subnode 1 to form a marked image, and send the marked image to the user terminal through the wireless communication parent node. The wireless communication parent node is also used to feedback the light signal flicker frequency requirement information to the user terminal after receiving the indoor navigation request sent by the user terminal. After receiving the light signal flicker frequency requirement information, the user terminal collects the light signal flicker frequency information in the current environment after the posture of the user terminal satisfies the horizontal screen upward, and sends it to the wireless communication parent node; the wireless communication parent node is also used to establish an association relationship between the light signal flicker frequency information and the MAC address after receiving the light signal flicker frequency information, and access the light signal flicker frequency information and fixed position information association table through the positioning server to determine the fixed position information of the visible light emission sub-node 1, and send the fixed position information to the user terminal. The user terminal is also used to collect the user's walking vibration information, generate the user terminal estimated coordinate information in real time according to the walking vibration information, and use the current coordinate information to correct the estimated coordinate information; the user terminal is also used to display the estimated coordinate information when the light signal flicker frequency information emitted by the visible light emission sub-node 1 cannot be collected.

[0064] The specific workflow for user A to achieve indoor positioning through a smartphone is as follows:

[0065] Indoor navigation request: User A uses his smartphone to open the indoor navigation application in the library, selects the destination, and sends an indoor positioning navigation request.

[0066] Optical signal flashing frequency demand feedback: After the wireless communication parent node (router) receives the indoor navigation request sent by the user terminal, it feeds back the required optical signal flashing frequency information to the user terminal.

[0067] Light signal flicker frequency collection: User A adjusts the posture of the smartphone to ensure that the screen is horizontal and facing upward. The smartphone starts to collect light signal flicker frequency information in the current environment.

[0068] Light signal information transmission: The smartphone sends the collected light signal flashing frequency information to the wireless communication parent node.

[0069] Establishing an association relationship: After the wireless communication parent node receives the optical signal flashing frequency information, it establishes an association relationship between the information and the MAC address of the user terminal.

[0070] Fixed position information query: The wireless communication parent node accesses the pre-stored association table of optical signal flashing frequency information and fixed position information through the positioning server to determine the fixed position information of the visible light emitting sub-node 1 where the user terminal is located.

[0071] Fixed location information transmission: The positioning server sends the queried fixed location information to the user terminal through the wireless communication parent node.

[0072] BIM model and marked image: The positioning server marks the fixed position information of the visible light emitting sub-node 1 in the BIM model and generates a marked image. Then, the marked image is sent to the user terminal through the wireless communication parent node.

[0073] User terminal location information display: After the user terminal receives the fixed location information and marked pictures, it displays this information on the screen to help user A understand his specific location in the library.

[0074] Walking vibration information collection: The smartphone continuously collects the user's walking vibration information.

[0075] Estimated coordinate information generation: The smartphone generates estimated coordinate information in real time based on the collected walking vibration information.

[0076] Coordinate information correction: The smartphone uses the current coordinate information received from the positioning server to correct the estimated coordinate information to improve positioning accuracy.

[0077] Display of estimated coordinate information: When the smartphone cannot collect the flashing frequency information of the light signal emitted by the visible light emitting subnode 1, the estimated coordinate information will be displayed to assist user A in indoor navigation.

[0078] Navigation path generation and display: The positioning server generates a navigation path in the BIM model based on the corrected coordinate information and target address information of the user terminal, and sends it to the user terminal. The user terminal displays the navigation path to guide user A to the destination.

[0079] User navigation to the destination: User A moves within the library along the route planned by the system according to the navigation path information displayed on the smartphone until reaching the target location.

[0080] This workflow demonstrates how user A can use a smartphone to achieve accurate positioning and navigation in an indoor environment, including how to use walking vibration information for position estimation and correction when the signal is poor.

[0081] Example 4

[0082] Compared with Example 3, the only difference is that the visible light intensity receiving subnode 3 is also used to collect ground light intensity information, based on the flashing frequency of the light signal emitted by the visible light emitting subnode 1, collect the brightness when the visible light emitting subnode 1 is turned on as the ground light intensity information, and collect the brightness when the visible light emitting subnode 1 is blocked as the ambient light intensity information, and send the ambient light intensity information corresponding to the visible light emitting subnode 1 to the positioning server through the wireless communication parent node; the positioning server is also used to use the light propagation attenuation formula to determine the Z-axis coordinate information of the user terminal based on the ground light intensity information and the real-time light intensity information and the distance information between the visible light emitting subnode 1 and the visible light intensity receiving subnode 3, and use the ambient light intensity information as a correction parameter of the light propagation attenuation formula. The light propagation attenuation formula is:

[0083]

[0084] Where d2 is the distance between the user terminal and the visible light emitting subnode 1, is the distance between the visible light intensity receiving subnode 3 and the visible light emitting subnode 1, is the ground light intensity information, For real-time light intensity information, It is the ambient light intensity information.

[0085] In specific use, an example of the workflow of user A achieving indoor positioning through a smartphone is shown below, including the new functions of the visible light intensity receiving sub-node 3 and the application of the light propagation attenuation formula:

[0086] Indoor navigation request: User A uses his smartphone to open the indoor navigation application in the library, selects the destination, and sends an indoor positioning navigation request.

[0087] Light signal flicker frequency collection: After the smartphone receives the light signal flicker frequency requirement information fed back by the wireless communication parent node, it adjusts the screen posture to be horizontal and upward, and starts to collect the light signal flicker frequency information in the current environment.

[0088] Visible light intensity receiving sub-node 3 works: Visible light intensity receiving sub-node 3 (photosensitive sensor) is installed on the ground. According to the flashing frequency of the light signal emitted by the visible light emitting sub-node 1, the brightness collected when the LED light is turned on is used as the ground light intensity information ( ), the brightness collected when the LED light is blocked is used as the ambient light intensity information ( ).

[0089] Light intensity information transmission: The visible light intensity receiving sub-node 3 sends the ground light intensity information and the ambient light intensity information to the wireless communication parent node.

[0090] Real-time light intensity information collection: The smartphone simultaneously collects the real-time light intensity information of the user terminal’s current environment ( ).

[0091] Information transmission to the positioning server: The wireless communication parent node sends the received ground light intensity information, real-time light intensity information, ambient light intensity information and the MAC address information of the user terminal to the positioning server.

[0092] Distance calculation: The positioning server uses the light propagation attenuation formula to calculate the distance between the user terminal and the visible light emitting subnode 1 ( ). The formula is:

[0093] in, is the distance between the visible light intensity receiving subnode 3 and the visible light emitting subnode 1, is the ground light intensity information, For real-time light intensity information, It is the ambient light intensity information.

[0094] Z-axis coordinate determination: The positioning server determines the Z-axis coordinate according to the calculated distance ( ) and the distance information between the visible light transmitting subnode 1 and the visible light intensity receiving subnode 3 ( ), determine the coordinate information of the user terminal on the Z axis, and use the ambient light intensity information as a correction parameter for the light propagation attenuation formula.

[0095] Location information and navigation path generation: The positioning server combines the BIM model and the corrected coordinate information of the user terminal to generate navigation path information.

[0096] Navigation information transmission and display: The positioning server sends the navigation path information and the fixed position information of the visible light emission sub-node 1 to the user terminal through the wireless communication parent node. After receiving this information, the smartphone displays the user's current location and the navigation path to the destination on the screen.

[0097] User movement according to the navigation path: User A moves in the library along the route planned by the system according to the navigation path information displayed on the smartphone until reaching the destination.

[0098] In the whole process, user A's smartphone and the visible light transmitting subnode 1 and receiving subnode in the library work together to improve the accuracy of indoor positioning through accurate distance measurement and correction of ambient light intensity information. This indoor positioning system based on visible light communication (VLC) can not only provide accurate positioning information, but also work effectively in indoor environments with complex light conditions.

[0099] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. The common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement the scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for the ordinary technicians in the relevant field to implement this application. It should be pointed out that for the technicians in this field, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. The library indoor lighting control system based on the Internet of Things is characterized by: include: A plurality of visible light emitting sub-nodes, each of which comprises an emitting base, a first light source, a first polarizer, a first controller and a first communication module, wherein the first light source is embedded and fixed in the emitting base, the first polarizer is located above the first light source, the first polarizer is rotatably connected to the emitting base, and a first driving member for driving the first polarizer to rotate is provided in the emitting base; The first communication module is used to receive first control information, the first controller is used to generate a first control instruction according to a preset mode or the first control information, and the first driving member is used to drive the first polarizer to rotate according to the first control instruction to form flicker frequency information; A user terminal, wherein a second polarizer is fixed on the user terminal, and the user terminal receives light after passing through the second polarizer to obtain the flashing frequency information of the optical signal emitted by the visible light emitting sub-node; It also includes a plurality of visible light intensity receiving sub-nodes, which include a receiving base, a photosensitive receiving module, a second controller and a second communication module. The photosensitive receiving module is embedded and fixed in the receiving base. The photosensitive receiving module is used to sense the change of light intensity in the environment to obtain ground light intensity information, and feed it back to the second controller, and then send the ground light intensity information through the second communication module and send it to the first controller; It also includes a wireless communication parent node, several video acquisition child nodes and a positioning server; The wireless communication parent node is used to receive indoor positioning and navigation request information sent by the user terminal, wherein the indoor positioning and navigation request information includes the MAC address information and the target address information of the user terminal; Several visible light emitting sub-nodes are installed on the roofs of the paths in the library, and the range that can be illuminated by each visible light emitting sub-node is divided into small cells, which are used to independently send optical signals to the preset small cell range according to a preset flashing frequency. The preset flashing frequency is higher than 24 Hz. The optical signals emitted by the visible light emitting sub-nodes in adjacent small cells do not interfere with each other in frequency, and the optical signals include the fixed position information of the visible light emitting sub-node; Several visible light intensity receiving sub-nodes are fixed on the ground to collect ground light intensity information in the current environment, and then send the ground light intensity information to the wireless communication parent node; The user terminal is also used to collect the posture of the user terminal after sending the indoor positioning navigation request information, and after the screen posture of the user terminal is horizontally upward, collect the real-time light intensity information of the current environment and the light signal flickering frequency information emitted by the visible light emission sub-node, and send the real-time light intensity information and the light signal flickering frequency information to the wireless communication parent node, and then display the terminal image information through the display screen of the user terminal according to the user refresh frequency below the maximum refresh rate of the display screen, and synchronously send the user refresh frequency to the wireless communication parent node; Several video acquisition sub-nodes are installed on the roof to collect environmental image information within a preset range, identify the terminal image information in the environmental image information to obtain the identification frequency, then identify the environmental coordinate information of the terminal image information in the environmental image information, and send the identification frequency and environmental coordinate information to the wireless communication parent node; The positioning server pre-stores the frequency information and fixed position information of the optical signal emitted by each visible light emitting sub-node, and marks the positions of the visible light emitting sub-node, the visible light intensity receiving sub-node and the video acquisition sub-node in the pre-stored BIM model; Used to receive indoor positioning and navigation request information, ground light intensity information, real-time light intensity information, light signal flashing frequency information, user refresh frequency, identification frequency and environmental coordinate information sent by a wireless communication parent node, and then determine the Z-axis coordinate information of the user terminal according to the ground light intensity information and the real-time light intensity information and the distance information between the visible light transmitting sub-node and the visible light intensity receiving sub-node using the light propagation attenuation formula, and then identify the location information of the user terminal with the MAC address information corresponding to the identification frequency in the environmental image information according to the matching degree of the light signal flashing frequency information, the user refresh frequency and the identification frequency, and then determine the X-axis coordinate information and Y-axis coordinate information of the user terminal according to the location information of the user terminal in the environmental coordinate information, and then process the Z-axis coordinate information, the X-axis coordinate information and the Y-axis coordinate information into the current coordinate information in combination with the BIM model, and generate navigation path information according to the current coordinate information and the target address information, and send the navigation path information to the user terminal through the wireless communication parent node; The user terminal is also used to display the navigation path information.

2. According to the Internet of Things-based library indoor lighting control system of claim 1, it is characterized by: The positioning server is also used to determine the fixed position information of the visible light emitting subnode where the user terminal is located according to the light signal flickering frequency information and the pre-stored association table of the light signal flickering frequency information and fixed position information sent by the visible light emitting subnode, and send the fixed position information and the BIM model to the user terminal through the wireless communication parent node; The positioning server is also used to mark the fixed position information of the visible light emitting sub-node in the BIM model to form a marked image after determining the fixed position information of the visible light emitting sub-node, and send the marked image to the user terminal through the wireless communication parent node; the wireless communication parent node is also used to feedback the light signal flickering frequency requirement information to the user terminal after receiving the indoor navigation request sent by the user terminal. After receiving the light signal flickering frequency requirement information, the user terminal collects the light signal flickering frequency information in the current environment and sends it to the wireless communication parent node after the posture of the user terminal satisfies the screen horizontal upward. The wireless communication parent node is also used to establish an association relationship between the light signal flashing frequency information and the MAC address after receiving the light signal flashing frequency information, and access the light signal flashing frequency information and fixed position information association table through the positioning server to determine the fixed position information of the visible light emitting sub-node, and send the fixed position information to the user terminal; the user terminal is also used to collect the user's walking vibration information, generate the user terminal estimated coordinate information in real time according to the walking vibration information, and use the current coordinate information to correct the estimated coordinate information; the user terminal is also used to display the estimated coordinate information when the light signal flashing frequency information emitted by the visible light emitting sub-node cannot be collected.

3. The library indoor lighting control system based on the Internet of Things according to claim 2 is characterized in that: The first light source is an LED lamp, and the brightness of the LED lamp is adjustable.

4. The library indoor lighting control system based on the Internet of Things according to claim 3 is characterized by: The first controller is also used to automatically adjust the brightness of the first light source according to ground light intensity information.

5. The library indoor lighting control system based on the Internet of Things according to claim 4 is characterized in that: The first driving member is a stepping motor, which is used to accurately control the periodic rotation of the first polarizer.

6. The library indoor lighting control system based on the Internet of Things according to claim 5 is characterized by: The first polarizer and the second polarizer are both linear polarizers.

7. The library indoor lighting control system based on the Internet of Things according to claim 6 is characterized by: The user terminal includes a photoelectric sensor for receiving and converting optical signals into electrical signals.

8. The library indoor lighting control system based on the Internet of Things according to claim 7 is characterized in that: The user terminal is a smart phone.

9. The library indoor lighting control system based on the Internet of Things according to claim 8 is characterized in that: The user terminal is also used to collect changes in light intensity information and use the peak value as real-time light intensity information.

10. The library indoor lighting method based on the Internet of Things is characterized by: A system as claimed in any one of claims 1 to 9 is employed.

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