WO2020077516A1

WO2020077516A1 - Led array signal detection method, and device

Info

Publication number: WO2020077516A1
Application number: PCT/CN2018/110348
Authority: WO
Inventors: 刘鹏; 陈欣
Original assignee: 华北电力大学扬中智能电气研究中心
Priority date: 2018-10-16
Filing date: 2018-10-16
Publication date: 2020-04-23
Also published as: JP7182722B2; JP2022508842A

Abstract

An LED array signal detection method and a device. An LED array comprises N * N LEDs, where N is greater than or equal to 3, and positioning LEDs are defined as LEDs at four corner positions in the LED array. On-off states of the four positioning LEDs are pre-configured such that three of the positioning LEDs are on, and the remaining positioning LED is off. The method comprises: acquiring an image containing the LED array (200); detecting each light source from the image by means of a connected-component labeling algorithm (210); determining a position of each detected light source, and determining the positioning LEDs of the LED array in the image according to the position of each light source and the pre-configured on-off states of the four positioning LEDs (220); and determining positions of the positioning LEDs, performing detection on each light source according to the positions of the positioning LEDs and a grayscale value and the position of each light source, determining an on-off state of each LED in the LED array, and acquiring an LED array signal of the LED array (230). The invention is configured to achieve accurate identification of the positioning LEDs by means of the design of the positioning LEDs and the distance of each light source, and in turn to detect the LED array signal, thereby providing computational simplicity and improved efficiency.

Description

LED array signal detection method and device

Technical field

The invention relates to the technical field of optical communication, in particular to an LED array signal detection method and device.

Background technique

Image sensor communication (ISC) uses light emitting diodes (LEDs) as signal transmitters and image sensors as receivers. It is mainly used in intelligent transportation and indoor positioning. In addition, in order to improve communication performance, multi-input and multi-output (MIMO) technology is generally used in ISC systems. However, in the application process of MIMO-ISC technology, due to external interference and the presence of background light, etc., it is impossible to accurately detect the change of the LED, thereby reducing the system communication performance.

In the prior art, the LED array signal detection method mainly uses the edge algorithm, block growth method and frame difference method to identify the LED in the image to detect the LED array signal, but these methods have the following disadvantages: 1 ) The edge algorithm is difficult to implement and has low efficiency; 2) The block generation algorithm has low segmentation efficiency and high cost; 3) Although the frame difference method has small calculation and low complexity, it is sensitive to background noise and has poor recognition effect .

Summary of the invention

Embodiments of the present invention provide an LED array signal detection method and device to solve the problem of low efficiency and accuracy of LED array signal detection in the prior art.

The specific technical solutions provided by the embodiments of the present invention are as follows:

A light-emitting diode LED array signal detection method, the LED array includes N * N LEDs, where N is greater than or equal to 3, and the LEDs at four corner positions in the LED array are defined as positioning LEDs, and four positioning LEDs are preset The switch state is that three of the positioning LEDs are on and the remaining one is off. The method includes:

Obtaining an image containing the LED array;

A connected area labeling algorithm is used to detect each light source from the image;

Determine the positions of the detected light sources, and determine the positioning LEDs of the LED array from the image according to the positions of the light sources and the switch states of the four preset positioning LEDs;

Determine the position of the positioning LED, and detect each light source according to the position of the positioning LED, and the gray value and position of each light source, determine the switching state of each LED in the LED array, and obtain the LED array LED array signal.

Optionally, the positioning LEDs of the LED array are determined from the image according to the position of each light source and the switch states of the four preset positioning LEDs, which specifically include:

According to the position of each light source, calculate the distance between any two light sources in turn;

According to the calculated distance between any two light sources, determine the three light sources that can form an isosceles right triangle with the largest right-angle side;

If the determined right-angle side of the isosceles right-angled triangle is N-1 times the preset LED spacing of the LED array, the light sources of the three vertices of the isosceles right-angled triangle with the largest right-angled side are determined as The three switch states of the LED array are bright positioning LEDs;

According to the determined positioning LEDs whose three switch states are bright, the positions of the remaining positioning LEDs are determined.

Optionally, the method further includes: if it is determined that at least two right-angled sides have an isosceles right-angled triangle whose value is N-1 times the predetermined LED interval, then at least two LEDs corresponding to the isosceles right-angled triangles are counted The number of light sources in the array area, and the light sources at the three vertices of the isosceles right-angled triangle corresponding to the maximum number are determined to be the three positioning LEDs in the LED array whose switching state is bright.

Optionally, the method further includes: filtering out a distance not greater than the preset diagonal value of the LED array, and determining and executing three three isosceles right-angled triangles that can form the largest right-angled side according to the selected distance Light source steps.

Optionally, according to the position of the positioning LED, and the gray value and position of each light source, each light source is detected to determine the switching state of each LED in the LED array to obtain the LED array signal of the LED array , Including:

Respectively detecting the light sources, determining the switching state of the LEDs corresponding to the light sources, and obtaining the LED array signal of the LED array according to the switching state of the LEDs;

Wherein, when detecting any one of the light sources, specifically include:

Determine whether the gray value of any one light source is within the range of the preset minimum gray value and maximum gray value of the LED, and according to the determined position of any one positioning LED, the preset position error value and the preset LED spacing, determine the position interval of each LED in the LED array, and determine whether the position of any one light source is in the corresponding position interval;

If the judgment is YES, it is determined that the switch state of the LED corresponding to any one light source is on and decoded as 1, otherwise, the switch state of the LED corresponding to any one of the light sources is determined to be off and decoded as 0.

An LED array signal detection device, the LED array includes N * N LEDs, where N is greater than or equal to 3, and the LEDs at four corner positions in the LED array are defined as positioning LEDs, and the switching states of the four positioning LEDs are preset For three of the positioning LEDs to be on and the remaining one to be off, the device includes:

An acquisition module for acquiring an image containing the LED array;

The detection module is used to detect each light source from the image by using a connected area labeling algorithm;

A first determining module, configured to determine the positions of the detected light sources, and determine the positioning LEDs of the LED array from the image according to the positions of the light sources and the switch states of the four preset positioning LEDs;

The second determination module is used to determine the position of the positioning LED, and respectively detect the light sources according to the position of the positioning LED, and the gray value and position of each light source, and determine the switching state of each LED in the LED array To obtain the LED array signal of the LED array.

Optionally, when determining the positioning LEDs of the LED array from the image according to the position of each light source and the switch states of the four preset positioning LEDs, the first determining module is specifically configured to:

Optionally, the first determining module is further configured to: if at least two right-angled sides are determined as isosceles right-angled triangles with a value of N-1 times the predetermined LED interval, at least two equal points are counted respectively The waist right-angled triangle corresponds to the number of light sources in the LED array area formed, and the light sources at the three vertices of the isosceles right-angled triangle corresponding to the maximum number are determined to be the positioning LEDs whose three switch states are bright.

Optionally, the first determining module is further configured to: filter out a distance not greater than the preset diagonal value of the LED array, and determine and execute to determine the largest square angle can be formed according to the selected distance Steps of three light sources of isosceles right triangle.

Optionally, according to the position of the positioning LED, and the gray value and position of each light source, each light source is detected to determine the switching state of each LED in the LED array to obtain the LED array signal of the LED array At this time, the second determining module is specifically used to:

Wherein, when detecting any one of the light sources, specifically include:

A computer device, including:

At least one memory for storing computer programs;

At least one processor for implementing the steps of any one of the above LED array signal detection methods when executing a computer program stored in a memory.

A computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, implements any of the steps of the LED array signal detection method described above.

In the embodiment of the present invention, the LED array includes N * N LEDs, where N is greater than or equal to 3, and the LEDs at the four corner positions in the LED array are defined as positioning LEDs, and the switching states of the four positioning LEDs are preset as Three positioning LEDs are on, and the other positioning LEDs are off; when performing LED array signal detection, specifically: acquiring an image containing the LED array; using a connected area marking algorithm to detect each light source from the image; Determine the position of each detected light source, and determine the positioning LED of the LED array from the image according to the position of each light source and the switch state of the four preset positioning LEDs; determine the position of the positioning LED, and according to the positioning The position of the LED, and the gray value and position of each light source, respectively detect the light source, determine the switching state of each LED in the LED array, obtain the LED array signal of the LED array, so that the LED array The four corners of the LED are defined as positioning LEDs, and set three on and one off, so that the positioning LED can be accurately identified from the image according to the distance of the light source and the position of the positioning LED switch, and the accuracy is high. Simple calculation, calculation speed, and thus can be positioned according to the LED, the LED arrays detected signal, the detection efficiency and accuracy.

In addition, the positioning LED of the LED array is turned on and off three times, which not only facilitates the determination of the location of the identified LED and thus the range of the LED array, but also determines the positive direction of the LED array and corrects the LED array according to the switching state of the positioning LED. The position of it is convenient to decode the line by line to obtain the LED array signal and improve the accuracy.

BRIEF DESCRIPTION

The drawings incorporated in and forming a part of the specification illustrate embodiments of the invention, and together with the description thereof, serve to explain the principles of the invention.

FIG. 1 is a schematic structural diagram of an ISC system based on MIMO in an embodiment of the present invention;

2 is a flowchart of a method for detecting LED array signals in an embodiment of the present invention;

3 is a schematic diagram of the detection result of the connected region marking algorithm in the embodiment of the present invention;

FIG. 4 is a schematic diagram of the identification result of the positioning LED in the first case in the embodiment of the present invention;

FIG. 5 is a schematic diagram of the identification result of the positioning LED in the second case in the embodiment of the present invention;

6 is a schematic diagram of a recognition result of a positioning LED in a third case in an embodiment of the present invention;

7 is a schematic diagram of the principle of decoding LED array signals based on positioning LEDs in an embodiment of the present invention;

8 is a schematic structural diagram of an LED array signal detection device according to an embodiment of the present invention;

9 is a schematic structural diagram of a computer device in an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

In practice, the light emitting diode (LED) light source can be used not only for lighting, but also for communication. The signal is transmitted through the change of the light and dark of the LED light source. Visible light communication (VLC) is a type of LED. The technology of wireless communication that changes light and shade. In order to improve reliability and efficiency, the image sensor can be used as the receiving end, that is, image sensor communication (ISC). ISC uses LED as the signal transmitting end and the image sensor as the receiving end, which can be applied to intelligent transportation and For indoor positioning and other scenarios, the key to ISC communication is accurate identification of LEDs. In addition, in order to improve communication performance, multi-input and multi-output (MIMO) technology is usually applied to ISC systems. However, in MIMO-ISC systems, due to the presence of external interference and background light noise, etc., the image The sensor cannot accurately recognize the change of the LED, thereby reducing the communication performance. In the prior art, several LED array signal detection methods are provided, mainly using edge algorithm, block growth method and frame difference method to identify and restore from the image LED array signals, however, these methods have low detection efficiency and accuracy for LED arrays.

Therefore, in the embodiment of the present invention, the LED array is used as the signal emitting end, mainly to identify and extract the LED array light source from the complex background noise, improve the recognition accuracy and efficiency, and design the positioning of the LED array at four corner positions in advance The working state of the LED is three on and one off. After taking the image containing the LED array with the image sensor, the connected area marking method is used to detect each light source in the image, and according to the position of each light source, the positioning LED is determined by finding the largest isosceles right triangle In order to determine the working status of each LED in the LED array, decode it, identify the information contained in the LED array, and obtain the transmitted optical signal.

Referring to FIG. 1, it is a schematic structural diagram of an ISC system based on MIMO in an embodiment of the present invention, which includes at least a receiving end and a sending end.

Part 1: The sending end. The sending end includes at least signal input, modulation, LED array driver, and LED array emitting end part.

The basic principle of the sending end is: input a binary sequence signal, convert the binary sequence signal into a parallel multi-channel digital signal after serial-to-parallel conversion, and then modulate each digital signal separately, for example, binary on-off key control (On-Off Keying, OOK) modulation, which is not limited in the embodiment of the present invention. Finally, based on the modulated signal, the LED array driver is driven by the LED array driver to work, that is, the switching state of each LED in the LED array is changed, and the signal is transmitted through the lens.

Furthermore, in the process of signal communication, the input source signal can also be encoded first and then transmitted to improve reliability.

That is to say, in the embodiment of the present invention, the modulated signal can be loaded into the LED array and emitted, for example, the LED in the LED array can be lit to indicate “1” and off to indicate “0”.

Among them, in the embodiment of the present invention, the LED array includes N * N LEDs, where N is greater than or equal to 3, in order to facilitate the receiver to accurately identify the LED array signal, the LEDs at four corners of the LED array are defined as positioning LEDs, and The switch state of the four positioning LEDs is preset as three of the positioning LEDs are on, and the remaining one of the positioning LEDs is off, and the position of the on-positioning LED and the off-positioning LED in the LED array can also be set.

In this way, the working status of the positioning LED and the position in the LED array in the embodiment of the present invention can not only facilitate the accurate detection of the LED array signal at the receiving end, but also facilitate the positioning of the LED array at the receiving end, and can be used to detect the emission The area at the end, determine whether the picture is distorted, and estimate the LED array correction parameters, such as the rotation angle.

Part 2: The receiving end. The receiving end includes at least a lens, an image sensor, a digital image processing and decoding part.

The basic principle of the receiving end is: real-time shooting through the image sensor to obtain the image containing the LED array, then, read the captured image, perform digital image processing on the image, detect and identify each light source in the image, determine the positioning LED, and finally, according to the positioning Determine the LED, decode it, determine the switching state of each LED in the LED array, and restore the transmitted binary sequence signal, that is, the LED array signal.

Among them, the digital image processing of the image is mainly implemented in the embodiment of the present invention, and decoding is performed to obtain the LED array signal, which will be specifically described in the LED array signal detection method below.

It is worth noting that the system principle structure diagram in the embodiments of the present invention is to more clearly explain the technical solutions in the embodiments of the present invention, and does not constitute a limitation on the technical solutions provided in the embodiments of the present invention. For other system structures and For business applications, the technical solutions provided by the embodiments of the present invention are also applicable to similar problems.

In various embodiments of the present invention, the LED array signal detection method is used as a schematic structural diagram of the system shown in FIG. 1 as an example for schematic description.

Referring to FIG. 2, it is a flowchart of a method for detecting an LED array signal according to an embodiment of the present invention. The method includes:

Step 200: Acquire an image containing an LED array.

For example, the LED array sends a signal through the change of the switch status of each LED, and the LED array can be photographed in real time by a camera to obtain an image containing the LED array.

Step 210: A connected area labeling algorithm is used to detect each light source from the image.

Further, the image is binarized to obtain a binarized image, so that a connected region labeling algorithm can be used to detect the light source from the binarized image.

Among them, the basic principle of the connected area labeling algorithm is: use the second traversal to complete the labeling. During the first round of traversal, the image is scanned line by line, and the connected area is marked as a cluster. The clusters of all lines except the first line, if If there is an overlap between the groups in the previous row, the group is given the smallest label of the connected group, and the labels of these groups with the same label are equivalent. During the second round of traversal, the labels of the starting group are traversed to find the equivalent sequence. Relabel.

Referring to FIG. 3, which is a schematic diagram of the detection result of the connected area marking algorithm in the embodiment of the present invention, it can be seen that the areas of each light source can be marked, and the center of each area can be regarded as the position of the light source, so that all light source positions can be obtained, including The positions of the LED light source and the interference source are determined afterwards to determine whether the light source at each position is an LED or an interference source.

In this way, the connected area labeling algorithm is used to detect the light source, which is more efficient and takes less time. For images of different frames, the time is the same.

Step 220: Determine the positions of the detected light sources, and determine the positioning LEDs of the LED array from the image according to the positions of the light sources and the switch states of the four positioning LEDs set in advance.

When step 220 is executed, it specifically includes:

First, according to the position of each light source, the distance between any two light sources is calculated in sequence.

For example, if there are 3 light sources, namely light source 1, light source 2 and light source 3, then calculate the distance between light source 1 and light source 2, light source 1 and light source 3 and light source 2 and light source 3 in sequence, and record the calculated The distance and the position of the corresponding light source.

Then, based on the calculated distance between any two light sources, three light sources that can form an isosceles right triangle with the largest right-angle side are determined.

Specifically, according to each distance recorded and the light source corresponding to each distance, three light sources capable of forming an isosceles right-angled triangle are sequentially determined, and three light sources corresponding to the isosceles right-angled triangle with the largest right-angle side are determined.

Further, in order to facilitate calculation and determination, in this embodiment of the present invention, the distances of the light sources can be sorted first from small to large, so that the isosceles right-angled triangle with the largest right-angled side can be determined faster according to the sorted distance.

Then, if the determined right-angle side of the isosceles right-angled triangle is N-1 times the preset LED spacing of the LED array, the light source of the three vertices of the isosceles right-angled triangle with the largest right-angled edge is determined as the LED array The three switch states are the bright positioning LED.

It should be noted that in an ideal state, the value of the right-angle side of the largest isosceles right-angled triangle should be N-1 times the LED pitch of the N * N LED array, so the largest isosceles right-angled triangle can also be called It is an ideal isosceles right-angled triangle. For ease of description, the following is a right-angled isosceles right-angled triangle with N-1 times the LED pitch of the N * N LED array, referred to as an ideal isosceles right-angled triangle, but in actual There may be some position errors, and the determined right-angle side of the largest isosceles right-angled triangle may not be N-1 times the LED spacing. Therefore, in order to improve the accuracy of judgment, a possible In an embodiment, an error threshold is set, and if the value of the right-angle side of the determined isosceles right-angled triangle is within the error threshold range of N-1 times the LED pitch, the light sources of the three vertices of the isosceles right-angled triangle are determined to be LEDs The three switch states of the array are bright positioning LEDs.

In the embodiment of the present invention, since three of the positioning LEDs in the LED array are always on, the light source in the captured image will contain these three positioning LEDs, and the three positioning LEDs are located at the corners according to the positioning LEDs. The positioning LEDs can form the characteristic of the largest isosceles right-angled triangle. Therefore, in the embodiment of the present invention, three positioning LEDs in a bright state can be determined by searching for the largest isosceles right-angled triangle.

Further, when determining an isosceles right triangle, it can be divided into the following situations:

The first case: there is only one ideal isosceles right triangle.

Referring to FIG. 4, it is a schematic diagram of the identification result of the positioning LED in the first case in the embodiment of the present invention. It can be seen that there may be multiple isosceles right-angle triangles in determining the isosceles right-angle triangle, but the right-angle side is the largest and takes values There is only one isosceles right-angled triangle that is N-1 times the LED pitch, that is, there is only one ideal isosceles right-angled triangle. For example, as shown in FIG. 4, three isosceles right-angled triangles are determined, but only one isosceles right-angled triangle triangle.

That is to say, in an ideal situation, there is only one ideal isosceles right-angled triangle for the image containing the LED array. Therefore, in this ideal situation, even if there is noise, it may not be affected very much. Only one can be determined Ideal isosceles right triangle.

Therefore, it can be determined that the light sources of the three vertices of the ideal isosceles right-angled triangle are the positioning LEDs whose three switch states of the LED array are bright.

The second case: at least two ideal isosceles right triangles.

Referring to FIG. 5, it is a schematic diagram of the identification result of the positioning LED in the second case in the embodiment of the present invention. In the embodiment of the present invention, due to the presence of noise, multiple ideal isosceles right triangles may be determined. Next, the maximum distance between the light sources may be greater than the diagonal value of the LED array. Therefore, it is necessary to identify the ideal isosceles right triangle composed of the positioning LEDs that actually belong to the LED array. This embodiment of the present invention provides a possibility The implementation of the ISC system is based on the actual working conditions of the ISC system, and the ideal isosceles right triangle that actually belongs to the LED array can be determined according to the method of probability theory, mainly by comparing the LED array composed of the positioning LEDs corresponding to each ideal isosceles right triangle The probability of the light source appearing in the area, the probability is the ideal isosceles right triangle that actually belongs to the LED array. For example, as shown in Figure 5, two ideal isosceles right triangles are detected, and these two ideal isosceles right triangles correspond The number of light sources in the LED array is different, and the LEDs in the actual LED array are arranged in an orderly and dense manner. Over the isosceles right triangle to be LED array comprises more light sources, therefore, the LED array more number of light sources over the isosceles right triangle is determined as corresponding to the ideal isosceles right triangle actually belong to the LED array in FIG. 5.

Specifically: if at least two right-angled isosceles right-angled triangles with a value of N-1 times the preset LED spacing are determined, the number of light sources in the LED array area corresponding to at least two isosceles right-angled triangles are respectively counted And determine the light sources of the three vertices of the isosceles right-angled triangle corresponding to the maximum number as the three LEDs of the LED array with the bright positioning LEDs.

The third case: there may be isosceles right-angled triangles with larger right-angled sides than ideal isosceles right-angled triangles.

Referring to FIG. 6, which is a schematic diagram of the recognition result of the positioning LED in the third case in the embodiment of the present invention, due to the presence of noise, an isosceles right-angled triangle with larger right-angle sides than an ideal isosceles right-angled triangle may also appear The value of the right-angle side is greater than N-1 times the LED spacing, which may be caused by noise or interference sources, and is usually not an ideal isosceles right-angled triangle for the LED array. For example, as shown in FIG. 6, two isosceles right-angled triangles are determined. Among them, the oblique side of the isosceles right-angled triangle on the upper left is larger than the length of the diagonal of the LED array, and in practice it is determined that the isosceles right-angled triangle does not belong to the LED array.

In order to avoid this situation and improve the efficiency of subsequent determination of ideal isosceles right-angled triangles, an embodiment of the present invention provides a possible implementation manner, after calculating the distance between the light sources, sort the distance from small to large At this time, only consider the value of the distance not greater than the hypotenuse of the ideal isosceles right triangle, that is, the value of the distance is not greater than the length of the diagonal of the LED array.

Specifically, the method further includes: filtering out a distance not greater than a predetermined diagonal value of the LED array, and according to the filtered distance, determining and executing the step of determining three light sources capable of forming an isosceles right triangle with the largest right-angle side .

In this way, according to the way of finding an ideal isosceles right triangle, it is easier to determine the positioning LED, the calculation speed is fast, and the efficiency is high.

Finally, according to the determined positioning LEDs whose three switch states are bright, the positions of the remaining positioning LEDs are determined.

Specifically, according to the characteristics of the uniform distribution of the LED array and the positions of the three determined positioning LEDs, the positions of the remaining one positioning LED are determined.

That is, since the four positioning LEDs can form a square, the position of the last remaining positioning LED can be determined according to the distance calculation, and the positioning LED at the position is in an off state, and there is no light source in the image.

In this way, in the embodiment of the present invention, the largest isosceles right triangle can be found according to the distance between the light sources, so as to determine the positioning LEDs in the LED array, for example, the determined positioning LEDs in the bright state are respectively located in the LED array (1,1), (1, n) and (n, 1), the positioning LED in the off state is located in (n, n) of the LED array.

Step 230: Determine the position of the positioning LED, and detect each light source according to the position of the positioning LED, and the gray value and position of each light source, determine the switching state of each LED in the LED array, and obtain the LED array signal of the LED array .

When step 230 is executed, it specifically includes:

First, determine the location of the LED.

After the four positioning LEDs of the LED array are determined, the position of the positioning LEDs in the image can be known.

Then, according to the position of the positioning LED, and the gray value and position of each light source, each light source is detected to determine the switching state of each LED in the LED array to obtain the LED array signal.

Specifically, traversing line by line, each of the light sources is sequentially detected, wherein the detection of any one light source is taken as an example for description.

1) It can be divided into two judgment conditions:

The first judgment condition: gray value judgment.

Specifically, it is determined whether the gray value of any one light source is within the range of the preset minimum gray value and maximum gray value of the LED.

For example, hij is the judgment result of the first judgment condition. If the gray value is determined to be within the range of the minimum gray value and the maximum gray value of the LED, the judgment result is 1, otherwise the judgment result is 0, that is:

Among them, thmax and thmin are respectively the maximum gray value and the minimum gray value of the LED, and Sij is the gray value of the light source (i, j) in the gray image.

The second judgment condition: according to the determined position of any one positioning LED, the preset position error value and the preset LED spacing, determine the position interval of each LED in the LED array, and determine whether the position of any one light source is in the corresponding In the location interval.

For example, taking any positioning LED as the positioning LED at the (1,1) position, for example, pij is the judgment result of the second judgment condition, and if it is determined that the calculated position is in the corresponding position interval, the judgment result is 1 , Otherwise the judgment result is 0, namely:

Among them, x_1, y_1 are the position coordinates of the positioning LED (1,1), d is the LED array spacing, and δ is the position error value.

Referring to FIG. 7, it is a schematic diagram of the principle of decoding LED array signals based on positioning LEDs in an embodiment of the present invention. As shown in FIG. 7, the four positioning LEDs are located at four corners of the LED array at positions (1, 1 ), (1, n), (n, 1) and (n, n), and the positioning LEDs at the (1,1), (1, n), (n, 1) positions are on and located at (n , N) The positioning LED in the off state is off. Therefore, according to the position of the off-positioning LED and the relative relationship between the off-positioning LED and the rest of the on-positioning LEDs, you can easily determine the location of (1, n ) Positioning LEDs, under normal circumstances, the position of the LED light source should be in the area composed of four positioning LEDs, and the LEDs in the LED array are fixedly arranged in sequence according to the spacing, so that they can be positioned according to the (1, n) position The coordinates of the LED, with LED (1, n) as the starting point, are decoded from (1, n) to (1,1) first, and then decoded line by line to determine whether the position of each light source is in line with the actual LED array. To determine whether it is an LED light source.

2) If the judgments are both yes, determine that the LED switch corresponding to any one light source is on and decode to 1, otherwise, determine that the LED switch corresponding to any one light source is off and decode to 0.

That is, when the LED array is detected and decoded, there are two judgment conditions. Only when both hij and pij are 1 at the same time, the LED corresponding to the position can be decoded to 1, otherwise it is decoded to 0.

In the embodiment of the present invention, after the image is binarized according to a preset threshold, the gray value of each light source is obtained, and the type of each light source is judged separately, that is, whether it is an LED or an interference source. If it is an LED light source, then The LED corresponding to the light source position is in a bright state and decoded as 1. If it is an interference source, for example, a light source caused by interference or overlap of surrounding light sources, the LED corresponding to the light source position is in an off state and decoded as 0.

In this way, the corresponding code value of each LED in the LED array can be decoded in sequence, and the LED array signal, that is, the input binary sequence signal can be detected according to the order.

Further, if the LED array is placed at a normal angle, it usually starts from the first bit in the upper left corner and carries the signal bits in order from left to right and from top to bottom, but the LED array may rotate and may be captured The picture containing the LED has a certain angle of rotation, so it is necessary to be able to correctly find the starting position of the signal sequence. In the embodiment of the present invention, the positioning LED of the LED array is defined, and the four positioning LEDs are designed to turn on and off three times. The position of the positioning LED and the positioning LED in the off state in the LED array are also preset. Therefore, in the embodiment of the present invention, the positioning LED in the off state can also be used as a reference positioning LED, according to the mutual position between the positioning LEDs Relationship, which can detect whether the LED array rotates, determine the rotation angle, correct the position of the LED array, rotate it to the correct angle, and can determine the starting position of the signal sequence, so that it can follow the predetermined LED during the decoding process The signal bits in the array are decoded sequentially to obtain the correct LED array signal.

In the embodiment of the present invention, the LEDs at the four corner positions in the LED array are defined as positioning LEDs, and the switching state of the four positioning LEDs is preset as three of the positioning LEDs are on, and the remaining one of the positioning LEDs is off. The image of the array uses the connected area labeling algorithm to detect each light source from the image, and determines the positioning LED according to the position of each light source and the distance between each other, so that according to the position of the positioning LED and the gray value of each light source And position, detect each light source separately, determine the switching status of each LED in the LED array, and obtain the LED array signal, so that the positioning LED can be accurately identified from the image according to the design of the positioning LED in the LED array, thereby detecting the LED Array signals, with fast calculation speed, can not only quickly detect LED array signals from the background light, but also be used in indoor positioning.

In addition, in the embodiment of the present invention, the direction of the LED array can also be determined, which is suitable for the rotation of the LED array, and the position of the LED array can be corrected to accurately detect the LED array signal.

Based on the above embodiment, referring to FIG. 8, which is a schematic structural diagram of an LED array signal detection device according to an embodiment of the present invention, wherein the LED array includes N * N LEDs, where N is greater than or equal to 3, and defines the LED array The LEDs located at the four corners are positioning LEDs. The switching status of the four positioning LEDs is preset, three of which are on, and the other one is off. The device specifically includes:

The obtaining module 80 is used to obtain an image containing the LED array;

The detection module 81 is used to detect each light source from the image by using a connected area labeling algorithm;

The first determining module 82 is used to determine the positions of the detected light sources, and determine the positioning LEDs of the LED array from the image according to the positions of the light sources and the switch states of the four preset positioning LEDs;

The second determining module 83 is used to determine the position of the positioning LED, and respectively detect the light sources according to the position of the positioning LED, and the gray value and position of each light source, and determine the switch of each LED in the LED array State, the LED array signal of the LED array is obtained.

Optionally, when determining the positioning LEDs of the LED array from the image according to the position of each light source and the switch states of the four preset positioning LEDs, the first determining module 82 is specifically configured to:

Optionally, the first determining module 82 is further configured to: if it is determined that at least two right-angled sides have an isosceles right-angled triangle with a value of N-1 times the predetermined LED interval, then at least two are counted respectively The isosceles right-angled triangle corresponds to the number of light sources in the LED array region formed, and the light sources at the three vertices of the isosceles right-angled triangle corresponding to the maximum number are determined to be the positioning LEDs whose three switch states of the LED array are bright.

Optionally, the first determining module 82 is further configured to: filter out a distance not greater than a predetermined diagonal value of the LED array, and determine and execute to determine that the largest right-angle side can be formed according to the filtered distance Steps of three light sources of an isosceles right triangle.

Optionally, according to the position of the positioning LED, and the gray value and position of each light source, each light source is detected to determine the switching state of each LED in the LED array to obtain the LED array signal of the LED array At this time, the second determining module 83 is specifically used to:

Wherein, when detecting any one of the light sources, specifically include:

Referring to FIG. 9, in an embodiment of the present invention, a schematic structural diagram of a computer device.

An embodiment of the present invention provides a computer apparatus. The server may include a processor 910 (Center Processing Unit, CPU), a memory 920, an input device 930, an output device 940, etc. The input device 930 may include a keyboard, a mouse, a touch screen, etc. The output device 940 may include a display device, such as a liquid crystal display (Liquid Crystal Display, LCD), a cathode ray tube (Cathode Ray Tube, CRT), and the like.

The memory 920 may include a read-only memory (ROM) and a random access memory (RAM), and provide the processor 910 with program instructions and data stored in the memory 920. In the embodiment of the present invention, the memory 920 may be used to store the program of the LED array signal detection method described above.

The processor 910 calls the program instructions stored in the memory 920, and the processor 910 is used to execute any LED array signal detection method in the embodiment of the present invention according to the obtained program instructions.

Based on the above embodiments, in an embodiment of the present invention, there is provided a computer readable storage medium on which a computer program is stored, and the computer program is executed by a processor to implement the LED array signal detection method in any of the above method embodiments .

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram and a combination of the flow and / or block in the flowchart and / or block diagram may be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, special-purpose computer, embedded processing machine, or other programmable data processing device to produce a machine that enables the generation of instructions executed by the processor of the computer or other programmable data processing device A device for realizing the functions specified in one block or multiple blocks of one flow or multiple blocks of a flowchart.

These computer program instructions may also be stored in a computer readable memory that can guide a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, the instructions The device implements the functions specified in one block or multiple blocks of the flowchart one flow or multiple flows and / or block diagrams.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operating steps are performed on the computer or other programmable device to produce computer-implemented processing, which is executed on the computer or other programmable device The instructions provide steps for implementing the functions specified in one block or multiple blocks of the flowchart one flow or multiple flows and / or block diagrams.

Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. In this way, if these modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and equivalent technologies thereof, the present invention is also intended to include these modifications and variations.

Claims

A light-emitting diode LED array signal detection method, characterized in that the LED array includes N * N LEDs, where N is greater than or equal to 3, and the LEDs at four corner positions in the LED array are defined as positioning LEDs. The switching status of the positioning LEDs is that three of the positioning LEDs are on and the remaining one is off. The method includes:

Obtaining an image containing the LED array;

A connected area labeling algorithm is used to detect each light source from the image;

Determine the positions of the detected light sources, and determine the positioning LEDs of the LED array from the image according to the positions of the light sources and the switch states of the four preset positioning LEDs;

Determine the position of the positioning LED, and detect each light source according to the position of the positioning LED, and the gray value and position of each light source, determine the switching state of each LED in the LED array, and obtain the LED array LED array signal.
The method of claim 1, wherein determining the positioning LED of the LED array from the image according to the position of each light source and the switch state of the four preset positioning LEDs specifically includes:

According to the position of each light source, calculate the distance between any two light sources in turn;

According to the calculated distance between any two light sources, determine the three light sources that can form an isosceles right triangle with the largest right-angle side;

If the determined right-angle side of the isosceles right-angled triangle is N-1 times the preset LED spacing of the LED array, the light sources of the three vertices of the isosceles right-angled triangle with the largest right-angled side are determined as The three switch states of the LED array are bright positioning LEDs;

According to the determined positioning LEDs whose three switch states are bright, the positions of the remaining positioning LEDs are determined.
The method of claim 2, further comprising:

If it is determined that at least two right-angled sides have an isosceles right-angled triangle with a value of N-1 times the predetermined LED interval, then the number of light sources in the LED array area corresponding to at least two isosceles right-angled triangles is counted, And the light sources at the three vertices of the isosceles right-angled triangle corresponding to the maximum number are determined as the three positioning LEDs of the LED array with the bright switching state.
The method of claim 2, further comprising:

A distance no greater than a predetermined diagonal value of the LED array is selected, and according to the selected distance, the step of determining three light sources that can form an isosceles right triangle with the largest right-angle side is determined and executed.
The method according to any one of claims 1 to 4, characterized in that, according to the position of the positioning LED, and the gray value and position of each light source, each light source is detected to determine each of the LED arrays The switching state of the LED to obtain the LED array signal of the LED array specifically includes:

Separately detecting the light sources, determining the switching state of the LEDs corresponding to the light sources, and obtaining the LED array signal of the LED array according to the switching state of the LEDs;

Wherein, when detecting any one of the light sources, specifically include:

Determine whether the gray value of any one light source is within the range of the preset minimum gray value and maximum gray value of the LED, and according to the determined position of any one positioning LED, the preset position error value and the preset LED spacing, determine the position interval of each LED in the LED array, and determine whether the position of any one light source is in the corresponding position interval;

If the judgment is YES, it is determined that the switch state of the LED corresponding to any one light source is on and decoded as 1, otherwise, the switch state of the LED corresponding to any one of the light sources is determined to be off and decoded as 0.
A light-emitting diode LED array signal detection device, characterized in that the LED array includes N * N LEDs, where N is greater than or equal to 3, and the LEDs at four corner positions in the LED array are defined as positioning LEDs, and four are preset The switch status of the positioning LEDs is that three of the positioning LEDs are on and the remaining one is off. The device includes:

An acquisition module for acquiring an image containing the LED array;

The detection module is used to detect each light source from the image by using a connected area labeling algorithm;

A first determining module, configured to determine the positions of the detected light sources, and determine the positioning LEDs of the LED array from the image according to the positions of the light sources and the switch states of the four preset positioning LEDs;

The second determination module is used to determine the position of the positioning LED, and respectively detect the light sources according to the position of the positioning LED, and the gray value and position of each light source, and determine the switching state of each LED in the LED array To obtain the LED array signal of the LED array.
The device according to claim 6, characterized in that, when the positioning LEDs of the LED array are determined from the image according to the position of each light source and the switch state of four preset positioning LEDs, the first determination The module is specifically used for:

According to the position of each light source, calculate the distance between any two light sources in turn;

According to the calculated distance between any two light sources, determine the three light sources that can form an isosceles right triangle with the largest right-angle side;

If the determined right-angle side of the isosceles right-angled triangle is N-1 times the preset LED spacing of the LED array, the light sources of the three vertices of the isosceles right-angled triangle with the largest right-angled side are determined as The three switch states of the LED array are bright positioning LEDs;

According to the determined positioning LEDs whose three switch states are bright, the positions of the remaining positioning LEDs are determined.
The apparatus of claim 7, wherein the first determining module is further used to:

If it is determined that at least two right-angled sides have an isosceles right-angled triangle with a value of N-1 times the predetermined LED interval, then the number of light sources in the LED array area corresponding to at least two isosceles right-angled triangles is counted, And the light sources at the three vertices of the isosceles right-angled triangle corresponding to the maximum number are determined as the three positioning LEDs of the LED array with the bright switching state.
The apparatus of claim 7, wherein the first determining module is further used to:

A distance no greater than a predetermined diagonal value of the LED array is selected, and according to the selected distance, the step of determining three light sources that can form an isosceles right triangle with the largest right-angle side is determined and executed.
The device according to any one of claims 6-9, characterized in that each light source is separately detected according to the position of the positioning LED and the gray value and position of each light source to determine each of the LED arrays In the switch state of the LED, when the LED array signal of the LED array is obtained, the second determining module is specifically used to:

Respectively detecting the light sources, determining the switching state of the LEDs corresponding to the light sources, and obtaining the LED array signal of the LED array according to the switching state of the LEDs;

Wherein, when detecting any one of the light sources, specifically include:

Determine whether the gray value of any one light source is within the range of the preset minimum gray value and maximum gray value of the LED, and according to the determined position of any one positioning LED, the preset position error value and the preset LED spacing, determine the position interval of each LED in the LED array, and determine whether the position of any one light source is in the corresponding position interval;

If the judgment is YES, it is determined that the switch state of the LED corresponding to any one light source is on and decoded as 1, otherwise, the switch state of the LED corresponding to any one of the light sources is determined to be off and decoded as 0.