CN112087260A - Color ring coding representation method for indoor positioning - Google Patents

Abstract

The invention provides a color circle coding representation method for indoor positioning. Firstly, inputting position information into an encoder in a transmitting module and coding; then the coded information is displayed by an LED lamp; receiving a visible light signal of the LED lamp through a light receiver; and finally, decoding the visible light signal to determine the position. The invention adopts color ring coding, and simplifies the modulator and the drive circuit part in the transmitting module; the post-stage processing circuit and demodulator are simplified in the receiving module. Compared with the prior art, the method is simpler and more convenient to operate, lower in cost and suitable for indoor positioning based on the LED lamp.

Description

A Color Ring Coding Representation Method for Indoor Positioning

technical field

The invention provides a color ring coding method. It is mainly used for the coding and identification of landmarks in indoor visible light positioning. It has high stability and precision, easy maintenance, low cost and great development value. The patented technology is not limited to landmark representation for indoor positioning, but can also be used in all application areas where coding is identified by cameras.

Background technique

With the development of contemporary science and technology, positioning technology is becoming more and more mature, attracting extensive attention from academia and industry. Among the many positioning systems, the most widely used is the Global Positioning System (GPS) developed by the US Department of Defense. However, GPS positioning technology is not suitable for complex urban building environments. On the one hand, users cannot maintain a line of sight with orbiting satellites; on the other hand, GPS signals are also difficult to penetrate the walls of urban buildings. , still get lost from time to time. Because of this, the new technology of indoor positioning system was proposed. In recent years, visible light indoor positioning technology, which has many advantages such as high precision, high security, and low energy consumption, has gradually attracted attention with the development of visible light communication.

Indoor visible light positioning technology is mainly used in positioning and navigation, smart supermarkets, industrial security and intelligent transportation. In some large exhibition halls, a complete indoor positioning system can be easily established by using the existing LED lighting equipment. Visitors hold a device that can receive LED light signals. The device obtains the location of the visitor through signal analysis, and sends an explanation of the exhibits at the current location. The same principle, positioning technology can also be used to send commodity information within the supermarket. In Japan, large supermarkets have installed receivers on shopping carts to determine the current location according to the received signals, quickly remind users of the specific location information of various commodities and choose the best route to go. In electromagnetically sensitive places such as airports or hospitals, it is a good choice to use LED visible light to track the position. For example, under the existing LED lighting of the airport hall, passengers can know their own and the location of the boarding gate.

However, at present, the visible light indoor positioning technology has not been able to be maturely introduced to the market. On the one hand, the infrastructure is not yet perfect, but the main reason is that the technology is not yet mature. Including the following aspects:

1) The LED lamp as a landmark needs to be encoded by a modulation circuit, which is technically difficult and has high production, installation and maintenance costs;

2) The indoor positioning system based on LED lights has poor stability and is easily affected by system noise and external ambient light.

In 1998, Grantham Pang et al. from the University of Hong Kong first proposed the concept of using fast-switching LEDs and modulating visible light for communication, which has received extensive attention in the field of wireless communication. Subsequently, the research on visible light positioning began in 2000. First, Professor Nakagawa and others from Keio University in Japan were engaged in the research of visible light communication positioning based on semiconductor lighting and traffic lights. Later, in 2003, the Visible Light Communication Consortium (VLCC) was established to Promote and regulate visible light technology.

The current indoor visible light positioning technology research is mainly divided into two aspects: image-based positioning technology and non-image-based positioning technology. Image-based positioning technology mainly uses image sensors and mobile phone cameras to analyze and locate the received light information images, or use image frame information for positioning. Non-image-based positioning technology research is more: using received visible light time difference of arrival information (TDOA), intensity information (RSSI), angle information (AOA), or LHD-ID information for positioning.

Based on the image positioning technology, the image sensor or the camera of the smartphone is mainly used to calculate and locate the geometric relationship between the distance and the position difference of the LED image on the image sensor. The LED lights on the ceiling send position data information, and the receiving end is an image sensor to determine the direction of incident light and demodulate the transmitted visible light landmark data through the received image.

In order to overcome the problem that LED landmark lights need to be modulated, Xu Luping and others from Xidian University proposed an indoor positioning system based on indoor lighting features, using image processing technology and Kalman filtering algorithm. The system firstly collects video for indoor lighting, and extracts lighting features from the collected images. Secondly, the lighting feature information is sent to a pre-established specific indoor environment lighting feature recognition library for matching and identification. The indoor positioning algorithm and tracking algorithm are further designed to calculate the actual position of moving objects in the indoor environment, and predict the position coordinates of the objects at the next moment. The present invention proposes a low-cost landmark coding method based on color ring coding, which is used to replace the modulated LED lamp landmark system. At present, the commonly used coding methods include bar code, two-dimensional code, etc., but they are not suitable for indoor positioning based on LED lights.

At present, the research on noise interference and error in LED indoor positioning system mainly includes: 1) shot noise; the noise caused by the received LED light signal, ambient light interference and dark current is the main noise of the system; 2) Thermal noise: On the one hand, it is due to the heating of the photodetector resistance, and on the other hand, there is thermal noise in the FET channel; 3) Multipath interference: In this system, the LED light is detected due to the reflection of the LED light through the surface of objects such as walls. 4) For the time-division multiplexed signal transmission protocol, there is still a synchronization error of the LED signal; 5) For the TOA-based positioning system, there is a clock synchronization error between the transmitter and the receiver; 6) Intersymbol interference: When multiple LEDs send their corresponding ID information or position information at the same time, especially when the data rate is high, it will lead to symbol overlap, etc., resulting in signal distortion; there are also some errors such as LED coordinate position error, quantization error, if inertial is used For sensor-assisted measurement, there are zero-chip instability, angular random walk noise, etc.

SUMMARY OF THE INVENTION

Aiming at the problems of the prior art, the present invention provides a color ring coding method for indoor positioning, which replaces LED modulation with color ring coding, and simplifies the modulator and driving circuit of the prior art in the transmitting module of the prior art part; the post-processing circuit and demodulator are simplified in the receiving module

In order to solve the technical problem, the method of the present invention comprises the following steps:

Step 1. Input the position information into the encoder in the transmitter module and encode it;

Step 2. Display the coded information with LED lights;

Step 3. The light receiver receives the visible light signal of the LED light;

Step 4. Decode the visible light signal to determine the location;

Described step 1, input position information to the encoder in the transmitter module and encode, the specific implementation is as follows:

种组合。Input the location information of different areas in the same room into the encoder in the transmitter module, after input, it will be randomly assigned to a 6-digit serial number different from other areas, as the color ring code of the area, the color ring code is composed of six. The colors are arranged and combined, the numbers 1-6 represent red, orange, yellow, green, blue, purple, and the number of combinations is total

kind of combination.

The step 2 is to display the coded information with LED lights, and the specific implementation is as follows:

The obtained color ring code is displayed on the LED lights on the roof of the indoor area represented by the color ring code in six concentric circles arranged from the inside to the outside according to the corresponding color. The diameter of the LED lights is 10cm-45cm, and each The edge interval of LED lights in indoor areas is greater than 30cm.

In step 3, the optical receiver receives the visible light signal of the LED lamp, and the specific implementation is as follows:

Turn on the light receiver device of the corresponding device, take a picture of the indoor roof, process the single-frame RGB picture into an HSV image, and then perform threshold segmentation on the obtained HSV image, segment it into foreground and background, and divide the segmented foreground image as HSV image The format records the visible light signal of the corresponding part of the picture. The HSV format is:

Hue (H): 0°～360°, measured by angle, the value range is 0°～360°, starting from red and counting counterclockwise, red is 0°, green is 120°, and blue is 240°.

Saturation (S): 0 to 255, indicating how close the color is to the spectral color. A color that can be seen as the result of a spectral color mixed with white. The greater the proportion of spectral colors, the higher the degree of color close to spectral colors, the higher the color saturation. The saturation is high, and the color is deep and vivid. The white light component of the spectral color is 0, and the saturation is the highest.

Brightness (V): 0 to 255, indicating the brightness of the color. For the light source color, the brightness value is related to the brightness of the illuminant; for the object color, this value is related to the transmittance or reflectance of the object. Typical values range from 0% (black) to 100% (white).

The step 4 is to decode the visible light signal to determine the location, and the specific implementation is as follows:

The recorded visible light signal information is processed by looking up the table, and the number of each digit in the color ring code is determined by looking up the table, and the numbers are combined to determine the indoor area represented by the color ring code of the LED lamp.

Table 1. Color ring codes corresponding to each HSV value

Beneficial effects of the present invention:

The present invention adopts color ring coding, which simplifies the modulator and driving circuit parts in the transmitting module; and simplifies the post-stage processing circuit and the demodulator in the receiving module. Compared with the prior art, the operation is simpler and the cost is lower, and it is suitable for indoor positioning based on LED lights.

Description of drawings

Figure 1 is an LED light with a color ring code of 511351;

Fig. 2 is a schematic plan view of indoor positioning using a navigation light;

3 is a block diagram of an indoor visible light positioning system in the prior art;

FIG. 4 is a block diagram of the indoor visible light positioning system of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

Step 1. Input the position information into the encoder in the transmitter module and encode it;

Step 2. Display the coded information with LED lights;

Step 3. The light receiver receives the visible light signal of the LED light;

Step 4. Decode the visible light signal to determine the location;

Described step 1, input position information to the encoder in the transmitter module and encode, the specific implementation is as follows:

种组合Input the location information of different areas in the same room into the encoder in the transmitter module, after input, it will be randomly assigned to a 6-digit serial number different from other areas, as the color ring code of the area, the color ring code is composed of six. The colors are arranged and combined, the numbers 1-6 represent red, orange, yellow, green, blue, purple, and the number of combinations is total

combination

The step 2 is to display the coded information with LED lights, and the specific implementation is as follows:

The obtained color ring code is displayed on the LED lights on the roof of the indoor area represented by the color ring code in six concentric circles arranged from the inside to the outside according to the corresponding color, and the corresponding LED lights have a diameter of 10cm-45cm. All can achieve good results, and the edge interval of LED lights in each indoor area should be at least greater than 30cm.

In step 3, the optical receiver receives the visible light signal of the LED lamp, and the specific implementation is as follows:

Turn on the corresponding device's camera or visible light sensor and other light receiver equipment, take a picture of the indoor roof, process a single-frame RGB picture into an HSV image, and then perform threshold segmentation on the obtained HSV image, segment it into foreground and background, and will be segmented. The foreground image records the visible light signal of the corresponding part of the picture in HSV format. The HSV format is:

Hue (H): 0°～360°, measured by angle, the value range is 0°～360°, starting from red and counting counterclockwise, red is 0°, green is 120°, and blue is 240°.

Saturation (S): 0 to 255, indicating how close the color is to the spectral color. A color that can be seen as the result of a spectral color mixed with white. The greater the proportion of spectral colors, the higher the degree of color close to spectral colors, the higher the color saturation. The saturation is high, and the color is deep and bright. The white light component of the spectral color is 0, and the saturation is the highest.

Brightness (V): 0 to 255, indicating the brightness of the color. For the light source color, the brightness value is related to the brightness of the illuminant; for the object color, this value is related to the transmittance or reflectance of the object. Typical values range from 0% (black) to 100% (white).

The step 4 is to decode the visible light signal to determine the location, and the specific implementation is as follows:

The recorded visible light signal information is processed by looking up the table, and the number of each digit in the color ring code is determined by looking up the table, and the numbers are combined to determine the indoor area represented by the color ring code of the LED lamp.

Table 1. Color ring codes corresponding to each HSV value

Claims (5)

1. a color ring coding representation method for indoor positioning, is characterized in that, step is as follows: Step 1. Input the position information into the encoder in the transmitter module and encode it; Step 2. Display the coded information with LED lights; Step 3. The light receiver receives the visible light signal of the LED light; Step 4: Decode the visible light signal to determine the location. 2. a kind of color ring coding representation method for indoor positioning according to claim 1, is characterized in that, described step 1, input position information in the encoder in the transmitting module and encode, concrete realization is as follows : Input the location information of different areas in the same room into the encoder in the transmitter module, after input, it will be randomly assigned to a 6-digit serial number different from other areas, as the color ring code of the area, the color ring code is composed of six. The colors are arranged and combined, the numbers 1-6 represent red, orange, yellow, green, blue, purple, and the number of combinations is total

kind of combination. 3. a kind of color ring coding representation method for indoor positioning according to claim 2, is characterized in that, described step 2 is to display coded information with LED light, and concrete realization is as follows: The obtained color ring code is displayed on the LED lights on the roof of the indoor area represented by the color ring code in six concentric circles arranged from the inside to the outside according to the corresponding color. The diameter of the LED lights is 10cm-45cm, and each The edge interval of LED lights in indoor areas is greater than 30cm. 4. a kind of color ring coding method for indoor positioning according to claim 3, is characterized in that, described step 3 light receiver accepts LED lamp visible light signal, and concrete realization is as follows: Turn on the light receiver device of the corresponding device, take a picture of the indoor roof, process the single-frame RGB picture into an HSV image, and then perform threshold segmentation on the obtained HSV image, segment it into foreground and background, and divide the segmented foreground image as HSV image The format records the visible light signal of the corresponding part in the picture; the HSV format is: Hue (H): 0°～360°, measured by angle, the value range is 0°～360°, starting from red and counting counterclockwise, red is 0°, green is 120°, and blue is 240°; Saturation (S): 0 to 255, indicating the degree to which the color is close to the spectral color; a color can be regarded as the result of mixing a certain spectral color with white; the greater the proportion of the spectral color, the color close to the spectral color The higher the degree is, the higher the saturation of the color; the higher the saturation, the darker and brighter the color; the white light component of the spectral color is 0, and the saturation is the highest; Brightness (V): 0 to 255, indicating the brightness of the color. For the light source color, the brightness value is related to the brightness of the illuminant; for the object color, this value is related to the transmittance or reflectance of the object; usually the value range is 0% (black) to 100% (white). 5. a kind of color ring coding method for indoor positioning according to claim 4, is characterized in that, described step 4 decodes the visible light signal, determines the location, and is specifically implemented as follows: The recorded visible light signal information is processed by a table lookup, and the number of each digit in the color ring code is determined by looking up the table, and the numbers are combined to determine the indoor area represented by the color ring code of the LED lamp; Table 1. Color ring codes corresponding to each HSV value H S V color code 0-22 or 312-360 43-255 43-255 red 1 22-52 43-255 43-255 orange 2 52-70 43-255 43-255 yellow 3 70-154 43-255 43-255 green 4 170-250 43-255 43-255 blue 5 250-312 43-255 43-255 purple 6 154-170 43-255 43-255 green no coding 0-360 0-255 0-43 black no coding 0-360 0-43 0-220 gray no coding .

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