CN112087260A

CN112087260A - Color ring coding representation method for indoor positioning

Info

Publication number: CN112087260A
Application number: CN202010933123.6A
Authority: CN
Inventors: 胡冀; 李致远
Original assignee: Hangzhou Dianzi University
Current assignee: Hangzhou Dianzi University
Priority date: 2020-09-08
Filing date: 2020-09-08
Publication date: 2020-12-15

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

Color ring coding representation method for indoor positioning

Technical Field

The invention provides a color circle coding method. The method is mainly used for the coding and identification of landmarks in indoor visible light positioning. The method has the advantages of high stability and precision, convenient maintenance, low cost and great development value. The technology of the patent is not only used for landmark representation of indoor positioning, but also can be used for all application fields of identifying and coding through a camera.

Background

With the development of modern science and technology, the positioning technology is mature day by day, and attracts the wide attention of the academia and the industry. Among the many positioning systems, the most widely used is the Global Positioning System (GPS) developed by the united states department of defense. However, the GPS positioning technology is not suitable for urban building environments with complex structures, and on one hand, users cannot keep the line of sight with an orbiting satellite; on the other hand, GPS signals are also difficult to penetrate walls of urban buildings, and people in rooms with complex structures still often lose their location. Because of this, a new technology of indoor positioning system is proposed. In recent years, attention has been paid to a visible light indoor positioning technology having many advantages such as high accuracy, high safety, and low power consumption, along with the development of visible light communication.

The indoor visible light positioning technology is mainly applied to positioning navigation, intelligent supermarkets, industrial safety and intelligent transportation. In some large-scale exhibition halls, the existing LED lighting equipment is utilized to conveniently establish a complete indoor positioning system. The visitor holds equipment capable of receiving the LED light signals, and the equipment obtains the position of the visitor through signal analysis and sends explanation introduction of the exhibit at the current position. Likewise, the location technology can also be used for sending commodity information inside the supermarket. In japan, a supermarket has already provided a receiver apparatus on a shopping cart, and the current position is determined based on a received signal, thereby quickly reminding a user of specific position information of various commodities and making a trip to select an optimal route. In places sensitive to electromagnetism, such as airports or hospitals, the tracking of the position by using the LED visible light is a good choice, for example, under the illumination of the existing LED lamps in an airport hall, passengers can know the positions of the passengers and a gate.

However, currently visible light indoor positioning technology has not been able to be put on the market at a mature time. On the one hand, the infrastructure is not yet complete, but the main reason is that the technology is not yet mature. The method comprises the following aspects:

1) the LED lamp used as the landmark needs to be coded through a modulation circuit, so that the technical difficulty is high, and the production, installation and maintenance costs are high;

2) the stability of an indoor positioning system based on the LED lamp is poor and is easily influenced by system noise and external environment light.

Grantham Pang et al, from hong kong university, first proposed the concept of using fast switching LEDs and modulating visible light for communication in 1998, which received extensive attention in the field of wireless communication. The study of visible light localization was started later from 2000, first with professor Nakagawa et al from the university of celebration, japan engaged in the study of visible light communication localization based on semiconductor lighting lamps and traffic lights, after which in 2003 the Visible Light Communication Consortium (VLCC) was established to facilitate and standardize visible light technology.

The current indoor visible light positioning technology research is mainly divided from two aspects: image-based localization techniques and non-image-based localization techniques. The image-based positioning technology mainly adopts an image sensor and a mobile phone camera to analyze and position a received optical information image or utilizes image frame information to position. The non-image-based positioning technology is researched more: the positioning is performed using received visible time difference of arrival information (TDOA), intensity information (RSSI), angle information (AOA), or LHD-ID information.

Based on an image positioning technology, an image sensor or a camera of a smart phone is mainly adopted, and calculation and positioning are carried out through the geometrical relation of the distance and the position difference of an LED image imaged on the image sensor. The LED lamp positioned on the ceiling sends position data information, and the receiving end is an image sensor which determines the incident light direction and demodulates the sent visible light landmark data through the received image.

In order to solve the problem that an LED landmark lamp needs to be modulated, the approved peace of technology university of electronic technology of Western Ann, et al, provides an indoor positioning system based on indoor lighting features and by using an image processing technology and a Kalman filtering algorithm. The system firstly carries out video acquisition on indoor decorative lighting and carries out decorative lighting feature extraction on the acquired image. Secondly, the lamp decoration characteristic information is sent to a pre-established specific indoor environment lamp decoration characteristic recognition library for matching recognition. An indoor positioning algorithm and a tracking algorithm are further designed to calculate the actual position of the moving object in the indoor environment, and the position coordinate of the object at the next moment is predicted. The invention provides a low-cost landmark coding method based on color circle coding, which is used for replacing a modulation LED lamp landmark system. At present, common coding methods comprise bar codes, two-dimensional codes and the like, but the encoding methods are not suitable for indoor positioning based on LED lamps.

The current research make internal disorder or usurp on noise interference and errors in LED indoor positioning systems mainly includes: 1) shot noise; noise due to received LED light signals, ambient light interference and dark current is the dominant noise of the system; 2) thermal noise: on one hand, the resistance of the photoelectric detector generates heat, and on the other hand, the channel of the field effect transistor has thermal noise; 3) multipath interference: in the system, the LED light is received by a detector due to the fact that the LED light is reflected by the surface of an object such as a wall; 4) for the time division multiplexing signal transmission protocol, the synchronization error of the LED signal also exists; 5) for a positioning system based on TOA, clock synchronization errors of a transmitting end and a receiving end exist; 6) intersymbol interference: when multiple LEDs simultaneously transmit information such as ID information or positions corresponding to the LEDs, particularly when the data rate is high, the conditions such as symbol overlapping and the like can be caused, so that signal distortion is caused; there are also errors such as LED coordinate position errors, quantization errors, if inertial sensor assisted measurements are used, zero-slice instability, angular random walk noise, etc.

Disclosure of Invention

Aiming at the problems of the prior art, the invention provides a color ring coding representation method for indoor positioning, which replaces led modulation with color ring coding and simplifies the modulator and the driving circuit part in the prior art in the transmitting module in the prior art; post-stage processing circuitry and demodulator in a receiver module

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

step 1, inputting position information into an encoder in a transmitting module and encoding;

step 2, displaying the coded information by an LED lamp;

step 3, the optical receiver receives the visible light signal of the LED lamp;

step 4, decoding the visible light signal to determine the position of the visible light signal;

step 1, inputting the position information to an encoder in the transmitting module and encoding, and specifically realizing the following steps:

inputting the position information of different regions in the same room into an encoder in a transmitting module, randomly allocating a serial number with 6 digits different from other regions after inputting the position information as a color ring code of the region, wherein the color ring code is formed by arranging and combining six colors, and the numbers of 1-6 respectively represent red, orange, yellow, green, blue, purple and the combined number is total

And (4) combination.

The step 2 displays the coded information by an LED lamp, and is specifically realized as follows:

and displaying the obtained color ring codes on the LED lamps of the indoor area roofs represented by the color ring codes in six concentric circles arranged from inside to outside according to corresponding colors, wherein the diameter of the LED lamps is 10cm-45cm, and the edge interval of the LED lamps in each indoor area is more than 30 cm.

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

the method comprises the steps of starting optical receiver equipment of corresponding equipment, shooting pictures of an indoor roof, processing single-frame RGB pictures into HSV images, performing threshold segmentation on the HSV images, segmenting the HSV images into a foreground and a background, and recording visible light signals of corresponding parts in the pictures of the segmented foreground images in an HSV format. The HSV format is as follows:

hue (H): the value ranges from 0 degree to 360 degrees measured by angles, the value ranges from 0 degree to 360 degrees, the red is 0 degree, the green is 120 degrees and the blue is 240 degrees calculated from the red in the anticlockwise direction.

Saturation (S): 0 to 255, which indicates the degree of color close to the spectral color. A color can be seen as the result of a mixture of a certain spectral color and white. The greater the proportion of spectral colors, the higher the degree of color approaching spectral colors and the higher the saturation of colors. High saturation and dark and bright color. The white light component of the spectral color is 0, and the saturation reaches the highest.

Luminance (V): 0-255, representing the brightness of the color, for the light source color, the brightness value is related to the brightness of the illuminant; for object colors, this value is related to the transmittance or reflectance of the object. Values typically range from 0% (black) to 100% (white).

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

and performing table look-up processing on the recorded visible light signal information, determining the number of each bit in the color circle codes through table look-up, combining the numbers, and determining the indoor area represented by the color circle codes of the LED lamp.

TABLE 1 color wheel code corresponding to each HSV value

The invention has the beneficial effects that:

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 LED lamp positioning device is simpler and more convenient to operate, lower in cost and suitable for indoor positioning based on the LED lamp.

Drawings

FIG. 1 is an LED lamp with color circle code 511351;

FIG. 2 is a schematic plan view of indoor positioning using navigation lights;

FIG. 3 is a block diagram of a prior art indoor visible light positioning system;

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

Detailed Description

The invention is further illustrated by the following figures and examples.

step 2, displaying the coded information by an LED lamp;

step 3, the optical receiver receives the visible light signal of the LED lamp;

Combination of seed

and displaying the obtained color ring codes on the LED lamps of the indoor area roof represented by the color ring codes by six concentric circles arranged from inside to outside according to corresponding colors, wherein the diameters of the corresponding LED lamps are 10cm-45cm, and the edge interval of the LED lamps in each indoor area is at least more than 30 cm.

and starting optical receiver equipment such as a camera or a visible light sensor of corresponding equipment, shooting an indoor roof picture, processing a single-frame RGB picture into HSV images, performing threshold segmentation on the obtained HSV images, segmenting the HSV images into a foreground and a background, and recording visible light signals of corresponding parts in the picture by the segmented foreground images in an HSV format. The HSV format is as follows:

TABLE 1 color wheel code corresponding to each HSV value

Claims

1. A color wheel coding representation method for indoor positioning is characterized by comprising the following steps:

step 2, displaying the coded information by an LED lamp;

step 3, the optical receiver receives the visible light signal of the LED lamp;

and 4, decoding the visible light signal and determining the position of the visible light signal.

2. The method as claimed in claim 1, wherein the step 1 of inputting the position information into an encoder in the transmitting module and encoding the position information is implemented as follows:

And (4) combination.

3. The color wheel code representation method for indoor positioning as claimed in claim 2, wherein the coded information in step 2 is displayed by LED lamps, and is implemented as follows:

4. The color wheel code representation method for indoor positioning as claimed in claim 3, wherein the step 3 optical receiver receives visible light signals of LED lamps, and is implemented as follows:

starting optical receiver equipment of corresponding equipment, shooting a picture of an indoor roof, processing a single-frame RGB picture into HSV images, then performing threshold segmentation on the obtained HSV images, segmenting the HSV images into a foreground and a background, and recording visible light signals of corresponding parts in the images of the segmented foreground images in an HSV format; the HSV format is as follows:

hue (H): 0-360 degrees, measured by angles, the value range is 0-360 degrees, the counter-clockwise direction is counted from red, the red is 0 degree, the green is 120 degrees, and the blue is 240 degrees;

saturation (S): 0-255, representing the degree of color approaching the spectral color; one color, which can be seen as the result of a mixture of certain spectral colors and white; the larger the proportion of the spectral color is, the higher the degree of the color close to the spectral color is, and the higher the saturation of the color is; the saturation is high, and the color is dark and bright; the white light component of the spectrum color is 0, and the saturation reaches the highest;

luminance (V): 0-255, representing the brightness of the color, for the light source color, the brightness value is related to the brightness of the illuminant; for object colors, this value is related to the transmittance or reflectance of the object; values typically range from 0% (black) to 100% (white).

5. The method as claimed in claim 4, wherein the step 4 decodes the visible light signal to determine the position, and is implemented as follows:

performing table look-up processing on the recorded visible light signal information, determining the number of each bit in the color circle codes through table look-up, combining the numbers, and determining the indoor area represented by the color circle codes of the LED lamp;

TABLE 1 color wheel code corresponding to each HSV value

H S V color code 0-22 or 312- 43-255 43-255 Red wine 1 22-52 43-255 43-255 Orange 2 52-70 43-255 43-255 Yellow colour 3 70-154 43-255 43-255 Green 4 170-250 43-255 43-255 Blue (B) 5 250-312 43-255 43-255 Purple pigment 6 154-170 43-255 43-255 Green leaf of Chinese cabbage Not to code 0-360 0-255 0-43 Black colour Not to code 0-360 0-43 0-220 Grey/white Not to code

。