KR102672463B1 - Artificial marker and recognizing system for the artificial marker - Google Patents

Abstract

The present invention relates to artificial markers and artificial marker recognition systems. The present invention includes a base portion coated with a light reflecting material, and at least one pattern portion disposed on the base portion and formed with a polarizing filter. A plurality of pattern parts may be provided, and each pattern part may have a different shape and polarization direction.
In the present invention, a polarizing filter can be mounted on a light receiving unit that detects an artificial marker, and the pattern of the artificial marker can be robustly recognized by the polarizing filter, or the same artificial marker can be recognized as a different pattern.

Description

Artificial marker and artificial marker recognition system {Artificial marker and recognizing system for the artificial marker}

The present invention relates to an artificial marker and an artificial marker recognition system, and includes an artificial marker having a base portion coated with a light-reflecting material, at least one pattern portion disposed on the base portion, and a light reflected from the artificial marker being incident. It relates to an artificial marker recognition system including a light receiver and a control unit that reads the pattern of the artificial marker incident through the light receiver.

With the development of unmanned systems, robots are increasingly driving autonomously indoors and outdoors and performing actions such as carrying and moving. For a robot to drive autonomously, it is necessary to avoid obstacles while driving, accurately determine where objects are stored, and the robot's position in space. For this purpose, various sensors are used. Camera sensors can be used to check the situation ahead, or LiDAR sensors can be used.

Meanwhile, artificial markers are also used to track the robot's own location or determine its destination. Artificial markers can be installed in an indoor space or outdoors so that a robot or person can determine their location through a sensor, or they can be used to attach an artificial marker to an object and classify the object using the unique ID of the marker. Artificial markers for existing color camera sensors are formed in various colors and patterns, and the artificial markers recognize captured images and obtain information.

However, LiDAR sensors or IR camera sensors do not detect color, so it is difficult to use existing artificial markers.

Accordingly, there is a need to develop artificial markers that can be easily recognized by LiDAR sensors or IR camera sensors. Additionally, there is a need to develop an artificial marker recognition system that can effectively recognize patterns using these artificial markers.

Republic of Korea Patent No. 10-1461316 (2014.11.06)

The purpose of the present invention is to provide an artificial marker that is easy to recognize even by a LiDAR sensor or an IR camera sensor.

The purpose of the present invention is to provide an artificial marker recognition system that allows a plurality of LiDAR sensors or IR cameras to recognize one artificial marker differently, making it easy to determine the location of a robot.

The artificial marker according to an embodiment of the present invention includes a base portion and a pattern portion. A light reflecting material may be applied to the base portion. The pattern portion is disposed on the base portion and may be formed as a polarizing filter.

In the artificial marker according to an embodiment of the present invention, the background portion may have a predetermined color.

The artificial marker according to an embodiment of the present invention includes a plurality of pattern units, and at least one pattern unit may be arranged in a different polarization direction from the other pattern units.

In the artificial marker according to an embodiment of the present invention, the base part may include a first base part and a second base part. The second base may be located inside the first base. At least one first pattern part may be disposed on the first base part. At least one second pattern portion may be disposed on the second base portion.

In the artificial marker according to an embodiment of the present invention, the first background portion and the second background portion may have different colors.

An artificial marker recognition system according to an embodiment of the present invention includes an artificial marker, a light receiver, and a control unit. The artificial marker may have a base portion and a pattern portion disposed on the base portion. Light reflected from an artificial marker may be incident on the light receiving unit. The control unit can read the pattern of the artificial marker incident through the light receiving unit.

In the artificial marker recognition system according to an embodiment of the present invention, the light receiving unit may be equipped with a polarizing filter.

In the artificial marker recognition system according to an embodiment of the present invention, a plurality of light receiving units may be provided. The polarization filter provided in at least one light receiving unit may have a different polarization direction from the polarizing filter provided in the other light receiving unit.

In the artificial marker recognition system according to an embodiment of the present invention, the light receiving unit may be mounted on a lidar sensor or an IR camera.

In the artificial marker recognition system according to an embodiment of the present invention, the light receiving unit and the control unit may be mounted on a moving object.

According to an embodiment of the present invention, the artificial marker can facilitate recognition even by a LiDAR sensor or an IR camera sensor.

According to an embodiment of the present invention, the position and movement direction of a moving object can be easily determined.

1 is a diagram showing an artificial marker according to an embodiment of the present invention.
Figure 2 is a diagram showing that polarizing filters forming a pattern portion in an artificial marker according to an embodiment of the present invention are arranged in different directions.
Figure 3 is a diagram showing a state in which an artificial marker according to an embodiment of the present invention is photographed by a LiDAR sensor.
Figure 4 is a diagram showing an artificial marker according to another embodiment of the present invention.
Figure 5 is a diagram showing a state in which an artificial marker is recognized while a moving object is moving in an artificial marker recognition system according to an embodiment of the present invention.
Figure 6 is a diagram showing a state in which a lidar sensor mounted on a moving object photographs an artificial marker.
Figure 7 is a diagram showing an artificial marker having two pattern portions with different polarization directions.
FIG. 8 is a diagram illustrating a state in which one artificial marker is recognized differently by a polarization filter of a light receiving unit in an artificial marker recognition system according to an embodiment of the present invention.
Figure 9 is a diagram showing a situation in which a moving object detects an artificial marker in an indoor space where the artificial marker is attached.

Since the present invention can be modified in various ways and have various embodiments, specific embodiments will be exemplified and explained in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention.

The terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as 'include' or 'have' are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. At this time, note that in the attached drawings, like components are indicated by the same symbols whenever possible. Additionally, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some components are exaggerated, omitted, or schematically shown in the accompanying drawings.

FIG. 1 is a diagram showing an artificial marker according to an embodiment of the present invention, and FIG. 2 is a diagram showing that polarizing filters forming a pattern portion in the artificial marker according to an embodiment of the present invention are arranged in different directions, Figure 3 is a diagram showing a state in which an artificial marker according to an embodiment of the present invention is photographed by a LiDAR sensor.

As shown in FIG. 1, the artificial marker 1000 according to an embodiment of the present invention includes a base portion 1100 and a pattern portion 1200. A light reflecting material is applied to the base portion 1100. As a light-reflecting material, reflective tape or reflective spray can be applied. LiDAR sensors or IR cameras recognize patterns by detecting laser light or infrared light reflected by light-reflecting materials.

The light reflecting material applied to the base portion 1100 may have a specific color. For example, the background portion 1100 may have a color such as white, red, blue, or yellow. The artificial marker 1000 of the present invention enables recognition using a LiDAR sensor or an IR camera, but a general camera capable of identifying colors may also be used as a sensor. Alternatively, a lidar sensor, an IR camera, and a general camera can be used in combination. In this case, the artificial marker 1000 can be identified by the color of the background portion 1100.

The pattern portion 1200 is disposed on the base portion 1100. Pattern portions 1200 of various shapes may be formed on the base portion 1100 so that various types of artificial markers 1000 disposed at different positions can be identified. Unique information is provided to the artificial marker 1000 by the various shapes and arrangements of the pattern portion 1200.

The pattern portion 1200 is formed of a polarizing filter. Light travels by vibrating in various directions, and a polarizing filter only passes light in a specific direction among the light vibrating in various directions. The pattern portion 1200 only passes light that vibrates in a specific direction among the light reflected from the base portion 1100 according to the arrangement direction.

The pattern portion 1200 may be formed in a line shape and arranged in a stripe or grid shape. Alternatively, it can be cut into various small block shapes and placed in various arrangements.

As shown in FIG. 2, in order to provide various unique information to the artificial marker 1000, a pattern portion 1200 formed of a polarizing filter is arranged on the base portion 1100 in various sizes and patterns. The pattern portion 1200 may be arranged in various polarization directions, such as 0°, 45°, or 90°.

As the light reflected from the reflector passes through the polarizing filter, the amount of light reflection decreases. Since a polarizing filter only passes light in a certain direction, the amount of light passing through varies depending on the direction in which the polarizing filter is attached.

The amount of light reflected through the pattern portion 1200 varies depending on the direction in which the pattern portion 1200 is disposed. The LiDAR sensor detects reflected light reflected from the artificial marker 1000, and a three-dimensional effect is given to the detected artificial marker image by the difference in the amount of reflected light received.

For example, compare the amount of light reflection when the pattern portion 1200 is disposed at 0° and when the pattern portion 1200 is disposed at 45°. As shown in FIG. 3, the image 100 of the artificial marker detected by the LiDAR sensor is structured in three dimensions. While the pattern portion 1200 arranged at 0° allows all reflected light to pass through, the pattern portion 1200 arranged at 45° allows only a portion of the reflected light to pass through, so the LiDAR sensor determines the distance to each pattern portion 1200. The difference is perceived as being about twice that. Accordingly, the artificial marker image 100 expressed in three dimensions is recognized as having holes 120 having different shapes and different depths formed on the three-dimensional background 110. Each artificial marker 1000 is recognized and identified as a different pattern depending on the shape and polarization direction of the pattern portion 1200. The artificial marker 1000 according to the present invention can provide information to the artificial marker 1000 through differences in the shape and arrangement of the pattern portion 1200 and the amount of light reflection due to the polarization direction of the pattern portion 1200.

When detecting the artificial marker 1000 using an IR camera, it may be recognized as a pattern with a difference in brightness due to a difference in the amount of light reflection of each pattern portion 1200.

FIG. 4 is a diagram illustrating an artificial marker according to another embodiment of the present invention, and FIG. 5 is a diagram illustrating a state in which an artificial marker is recognized while a moving object is moving in an artificial marker recognition system according to an embodiment of the present invention.

Mobile objects such as robots can travel indoors and outdoors with artificial markers attached. A plurality of artificial markers 1000 may be arranged to determine the location and mark a unique area along the traveling path of the moving object. When a moving object recognizes an artificial marker from a long distance, recognition is difficult if the artificial marker is small in size. Therefore, artificial markers need to be large in size to enable identification from a long distance.

As shown in FIG. 4, an artificial marker having a small-sized artificial marker may be placed inside a relatively large-sized artificial marker. For recognition at a distance, a large artificial marker, for example, a long-distance artificial marker (1000A) measuring several meters to tens of centimeters in size, can be formed.

When the artificial marker (1000') and the position of the moving object are close, the LIDAR sensor or IR camera recognizes the artificial marker (1000') in a small viewing range rather than a wide range. A small-sized near-field artificial marker (1000B) is placed inside the long-distance artificial marker (1000A) and can be recognized by the lidar sensor. The base portions of the far-distance artificial marker 1000A and the near-distance artificial marker 1000B may have different colors, and may have pattern portions of different shapes and arrangements.

Specifically, the remote artificial marker 1000A includes a first base portion 1100A and a first pattern portion 1200A. The short-distance artificial marker 1000B includes a second base portion 1100B and a second pattern portion 1200B. The second base portion 1100B is located inside the first base portion 1100A. The first background portion 1100A and the second background portion 1100B may have different colors. This is to consider an environment in which color cameras, rather than lidar sensors or IR cameras, are used.

At least one first pattern part 1200A is disposed on the first base part 1100A. At least one second pattern part 1200B may be disposed on the second base part 1100B. To enable easy recognition from a distance, the first pattern portion 1200A may be formed to be relatively larger than the second pattern portion 1200B.

A moving object traveling indoors can move to its destination by recognizing the long-distance artificial marker (1000A) and the short-distance artificial marker (1000B). As shown in FIG. 5, for example, assuming that the mobile object 2000 moves toward area A-1, area A-1 includes a distant artificial marker 1000A indicating area A and area A-1. Near-distance artificial markers 1000B displaying may be arranged to overlap each other outside and inside. The long-distance artificial marker (1000A) can be formed in a size of 1 to 2 m, and the near-distance artificial marker (1000B) can be formed in a size of several tens of centimeters.

The mobile object 2000 can recognize area A by the long-distance artificial marker 1000A at a distance of 10 m or more from the artificial marker 1000, and move in a direction toward which the artificial marker approaches. When the mobile object 2000 approaches the vicinity of area A, it can determine the exact location of A-1 by recognizing the short-range artificial marker 1000B located inside.

The pattern of the artificial marker 1000 may be recognized as a three-dimensional structure with different depth or a pattern with different brightness depending on the distance from the lidar sensor or IR camera. While the mobile object 2000 moves, the three-dimensional pattern of the artificial marker 1000 changes in depth, and its position can be accurately estimated by comparison with a previously stored pattern.

Figure 6 is a diagram showing a state in which a lidar sensor mounted on a moving object photographs an artificial marker, Figure 7 is a diagram showing an artificial marker having two pattern parts with different polarization directions, and Figure 8 is an embodiment of the present invention. This is a diagram showing a state in which one artificial marker is recognized differently by the polarization filter of the light receiver in the artificial marker recognition system according to , and FIG. 9 is a diagram showing a situation in which a moving object detects an artificial marker in an indoor space where an artificial marker is attached. .

As shown in FIG. 6, the artificial marker recognition system according to an embodiment of the present invention includes an artificial marker 1000, a light receiving unit 2100, and a control unit 2200. The artificial marker 1000 includes a base portion 1100 and a pattern portion 1200. The pattern portion 1200 is disposed on the base portion 1100.

Light reflected from the artificial marker 1000 is incident on the light receiving unit 2100. The light receiving unit 2100 may be a lens of a lidar sensor, IR camera, etc. A polarizing filter 2110 may be mounted on the light receiving unit 2100. The amount of light transmitted through the polarizing filter 2110 varies depending on the arrangement direction. The pattern of the artificial marker 1000 may be distorted by the polarization filter 2110 disposed on the light receiving unit 2100.

For example, consider the case where the artificial marker 1000 has a shape in which two square pattern parts 1200 are arranged on a rectangular base part 1100 (FIG. 7). Here, the pattern portion 1200a has a polarization direction of 45°, and the pattern portion 1200b has a polarization direction of -45°. The artificial marker 1000 can be recognized as an image 100 of a three-dimensional structure in the shape of a rectangular parallelepiped with square holes 120a and 120b disposed on the left and right sides by the pattern portions 1200a and 1200b.

Here, when the polarization filter 2110 of the light receiving unit 2100 of the LiDAR sensor has a polarization direction of 45°, the polarization direction is the same as that of the pattern unit 1200a, so most of the reflected light from the pattern unit 1200a is transmitted to the light receiving unit ( 2100). However, in the case of the pattern portion 1200b, the polarization direction is different from that of the polarization filter 2110, so only a portion of the reflected light from the pattern portion 1200b passes through the light receiving portion 2100. Accordingly, as shown in (a) of FIG. 8, the left square hole 120a of the artificial marker image 100 can be sensed as having a shallow depth, and the right square hole 120b can be sensed as having a deep sense of depth.

Conversely, when the polarization filter 2110 of the light receiving unit 2100 of the LiDAR sensor has a polarization direction of -45°, the polarization direction is different from that of the pattern unit 1200a, so only a portion of the reflected light from the pattern unit 1200a is transmitted to the light receiving unit. (2100) is transmitted. Additionally, in the case of the pattern portion 1200b, since the polarization direction is the same as that of the polarization filter 2110, most of the reflected light from the pattern portion 1200b passes through the light receiving portion 2100. Accordingly, as shown in (b) of FIG. 8, the left square hole 120a of the artificial marker image 100 can be sensed as having a deep depth, and the right square hole 120b can be sensed as having a shallow depth.

When a polarizing filter is mounted on the light receiving part of an IR camera, if the polarizing filter 2110 has a polarization direction of 45°, the left square hole 120a of the artificial marker image 100 is bright, and the right square hole 120b is bright. It may be perceived as dark.

Conversely, when the polarization filter 2110 has a polarization direction of -45°, the left square hole 120a of the artificial marker image 100 may be perceived as dark and the right square hole 120b may be perceived as bright.

In a plurality of LiDAR sensors or IR cameras, by setting the polarization direction of the polarization filter 2110 of the light receiver 2100 differently, one artificial marker can be recognized as a different pattern.

Marker recognition errors can be detected by using a configuration that recognizes one artificial marker as a different pattern. For one artificial marker, two LiDAR sensors or two IR cameras, each equipped with a polarization filter with a 90° difference in polarization direction, recognize the artificial marker, and the pattern of the artificial marker recognized by one sensor Other sensors perceive the image as reversed. In other words, errors in artificial marker recognition can be detected based on the difference between the normal marker pattern and the reversed marker pattern.

In the case of an IR camera, the angle between the artificial marker and the polarizing filter attached to the camera light receiver can be set variously to express different brightness. If one marker is recognized by multiple IR cameras equipped with filters with different polarization directions, different patterns can be read for each IR camera, allowing a lot of information to be stored in the marker. For example, in a situation where four IR cameras recognize one artificial marker, if the artificial marker can be recognized at four levels of brightness by adjusting the polarization direction, the first IR camera will display '123412341234...' ' pattern, the 2nd IR camera is '432143214321... ' pattern, IR camera number 3 is '213421342134... ' pattern, IR camera number 4 is '431243124312... 'patterns can be recognized.

Additionally, depending on the environment in which the artificial marker 1000 is located, external light may be unevenly irradiated, or brightness inside and outside may become uneven due to shadows, etc. In this case, the pattern of the artificial marker can be recognized more robustly by attaching a polarizing filter 2110 to the light receiving unit 2100 of the LiDAR sensor or IR camera. In another embodiment, the polarizing filter is rotatably mounted, so that the direction of polarization can be adjusted as needed.

Additionally, when multiple LiDAR sensors are directed at one artificial marker, the laser light output from each LiDAR sensor may affect other LiDAR sensors. At this time, the effect can be attenuated by attaching polarization filters with different polarization directions to the light receiving part of each LIDAR sensor.

The control unit 2200 can read the pattern of the artificial marker 1000 incident through the light receiving unit 2100. The control unit 2200 can read the pattern of the artificial marker 1000 and compare it with a pre-stored pattern to determine the location of a moving object or to find a desired place or object. The light receiving unit 2100 and the control unit 2200 may be mounted on the moving body 2000.

The moving object 2000 may be equipped with a plurality of LiDAR sensors, IR cameras, or color cameras, and each LiDAR sensor or IR camera may be equipped with polarization filters having different polarization directions.

As shown in FIG. 9, LiDAR sensors may be mounted on the left and right sides of the moving object 2000, and polarization filters having different polarization directions may be mounted on each LiDAR sensor.

The mobile body 2000 may travel on the first passage (P1) and the second passage (P2). The mobile object 2000 travels on the first passage P1 or the second passage P2 and can detect the artificial marker 1000 located in the center block. A plurality of pattern portions 1200 having different shapes and polarization directions may be formed on the artificial marker 1000.

If the polarization directions of the polarization filters mounted on the left and right light receivers of the moving object 2000 are different from each other, the control unit recognizes the same artificial marker 1000 as a different pattern. Accordingly, the control unit is capable of tracking the location of the passage along which the moving object 2000 is currently traveling and the position of the moving object.

Above, an embodiment of the present invention has been described, but those skilled in the art can add, change, delete or add components without departing from the spirit of the present invention as set forth in the patent claims. The present invention may be modified and changed in various ways, and this will also be included within the scope of the rights of the present invention.

1000: Artificial marker 1100: Base part
1200: pattern part 2000: moving object
2100: light receiving unit 2110: polarizing filter

Claims (10)

A base coated with a light-reflecting material; and
It includes a plurality of pattern parts disposed on the base part and formed of a polarizing filter,
The base portion includes a first base portion and a second base portion, and the second base portion is located inside the first base portion,
A plurality of first pattern portions are disposed on the first base portion,
A plurality of second pattern portions are disposed on the second base portion,
At least one first pattern portion among the plurality of first pattern portions has a polarization direction different from that of other first pattern portions, and at least one second pattern portion among the plurality of second pattern portions has a polarization direction different from that of the other second pattern portions. Artificial markers characterized by these different characteristics. delete delete delete According to paragraph 1,
An artificial marker, wherein the first background portion and the second background portion have different colors. An artificial marker having a base portion coated with a light reflecting material, and a plurality of pattern portions disposed on the base portion and formed with a polarizing filter;
a light receiving unit including a polarizing filter and receiving light reflected from the artificial marker; and
It includes a control unit that reads the pattern of the artificial marker incident through the light receiving unit,
The base part includes a first base part and a second base part, and the second base part is located inside the first base part,
A plurality of first pattern portions are disposed on the first base portion,
A plurality of second pattern portions are disposed on the second base portion,
At least one first pattern portion among the plurality of first pattern portions has a polarization direction different from that of other first pattern portions, and at least one second pattern portion among the plurality of second pattern portions has a polarization direction different from that of the other second pattern portions. An artificial marker recognition system characterized by these different features. delete According to clause 6,
An artificial marker recognition system wherein a plurality of light receiving units are provided, and a polarization filter provided in at least one light receiving unit has a different polarization direction from a polarizing filter provided in another light receiving unit. According to claim 6 or 8,
An artificial marker recognition system, wherein the light receiving unit is mounted on a lidar sensor or an IR camera. According to claim 6 or 8,
An artificial marker recognition system, wherein the light receiving unit and the control unit are mounted on a moving object.

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