System for carrying out figure separation and direction identification based on light curtain

Abstract

The invention relates to the technical field of storage automation, and particularly provides a system for carrying out figure separation and direction identification based on a light curtain. A light curtain unit in the system is used for transmitting and receiving infrared light beams and detecting the shielding condition of the light beams; the light curtain unit collects shielding information that the moving target shields the light beam emitted by the light curtain emitter in real time, and transmits the shielding information to the control unit; the control unit is used for processing the data acquired by the light curtain unit, analyzing the shielding length, the motion characteristic, the shielding characteristic and the light intensity attenuation curve of the light beam by the data, identifying a human body and an object, and judging the motion direction of the human body and the object; the output unit is used for transmitting an identification result of the control unit to an external execution unit to trigger corresponding control logic; the alarm reset unit is used for automatically resetting after an alarm event is relieved when alarm is detected, and an object staying in a protection area is sent away from the protection area, the system efficiently and accurately recognizes the human body and the object, the movement direction of the human body and the object can be judged, and system paralysis is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of warehouse automation, and in particular to a system for separating people and identifying directions based on a light curtain. Background Art

[0002] In the modern warehousing and logistics industry, the widespread use of automated equipment has greatly improved operational efficiency. However, there is usually a mixed flow of people and goods in the warehousing environment. How to accurately distinguish between people and objects to ensure personnel safety and operational efficiency is an urgent problem to be solved.

[0003] As a detection device based on infrared beams, light curtains have the advantages of fast response speed, high precision, and strong anti-interference ability, which can effectively solve the above problems. However, existing light curtain technology is mainly used for security protection and object detection, and has the following shortcomings: traditional light curtains can only detect object occlusion and cannot distinguish between human bodies and goods (such as pallets); they rely on fixed thresholds to determine the direction of movement and cannot adapt to complex movement patterns (such as turning on the spot); there is no fault self-recovery mechanism, and the system is paralyzed when the light curtain is blocked by foreign objects or the light source fails. Summary of the invention

[0004] In view of this, the present invention provides a system for separating people and identifying directions based on light curtains, which is used to efficiently and accurately identify people and objects, and can determine their movement directions to avoid system paralysis.

[0005] In a first aspect, the present invention provides a system for separating people and identifying directions based on a light curtain, characterized in that the system comprises: a light curtain unit, a control unit, an output unit, an external execution unit and an alarm reset unit; The light curtain unit includes a light curtain transmitter and a light curtain receiver which are relatively arranged in the storage channel, and are used for emitting and receiving infrared light beams and detecting the obstruction of the light beams. The light curtain unit collects the obstruction information of the light beam emitted by the light curtain transmitter by the moving target in real time, and transmits the obstruction information to the control unit, wherein the obstruction information includes the obstruction length, obstruction position and obstruction time, and the obstruction light intensity attenuation. The control unit is used for processing the data collected by the light curtain unit, analyzing the obstruction length, motion characteristics, obstruction characteristics and light intensity attenuation curve of the light beam, identifying human bodies and objects, and determining their movement directions. The output unit is used for transmitting the recognition result of the control unit to the external execution unit to trigger the corresponding control logic. The alarm reset unit is used for detecting the alarm, and automatically resets after the alarm event is released, so as to send the objects stagnant in the protection area out of the protection area.

[0006] Optionally, the scanning plane of the light curtain unit faces the area at a height of 30-50 cm from the floor of the storage passage; and upon initialization, the length, movement speed and movement direction of the moving target are pre-set in the light curtain unit as legal trigger event features for allowing passage.

[0007] Optionally, the control unit analyzes the occlusion length, motion characteristics, occlusion characteristics and light intensity attenuation curve of the light beam through a preset algorithm to determine whether the type of the moving target is a human body or an object; and extracts key parameters by fitting the light intensity attenuation curve through the least squares method, including: initial light intensity I 0 , used to reflect the reflectivity of the surface of the object. The initial light intensity of the metal tray is 100-200μW, and the initial light intensity of the human body is 10-30μW, that is, the initial light intensity of the metal tray is greater than that of the human body; the surface attenuation coefficient α is used to characterize the absorption characteristics of the material. The attenuation coefficient of human skin is 0.02-0.05, and the attenuation coefficient of the plastic box is 0.03-0.07, that is, the attenuation coefficient of human skin is greater than that of the plastic box; the human step frequency is 0.8-1.4Hz, and the interval time distribution of the corresponding light intensity occlusion event is 1.2-2.5s Poisson distribution. The mechanical movement of the object is usually uniform linear motion, that is, fixed occlusion interval. If the occlusion length changes intermittently, the occlusion time interval obeys the 1.2-2.5s Poisson distribution, and the occlusion light intensity decays exponentially, then the moving target is the human body; if the occlusion length remains unchanged or changes continuously, the occlusion time interval is a fixed interval, and the occlusion light intensity decays linearly, then the moving target is an object.

[0008] Optionally, the control unit determines the movement direction of the mobile target through a preset algorithm according to the light beam blocking sequence and blocking time; the movement direction is determined by the following rules: if the light beam blocking sequence conforms to the preset movement direction, it is determined to be a forward direction; if the light beam blocking sequence does not conform to the preset movement direction, it is determined to be a backward direction.

[0009] Optionally, the output unit transmits the recognition result of the control unit to the external execution unit, triggering the corresponding control logic, wherein the recognition result includes the type of the moving target and the direction of the moving target; when the external execution unit triggers the control logic to enter the alarm state, after the alarm event is lifted, the alarm reset unit is immediately started until the object that is stationary in the protection area leaves the protection area.

[0010] Optionally, when a person walks, the alternating movement of the legs causes the beam blocking interval time t to follow a Poisson distribution with a parameter λ, and its expression is: ; in , T is the average step frequency, which is 1.2-2.5s.

[0011] Optionally, the light intensity attenuation curve is defined as a function of the light intensity of the light beam reflected from the object surface and propagated to the light curtain receiver after time t, and its expression is: ; Among them, I0 is the initial light intensity; R(θ) is the reflectivity of the object surface, which is related to the incident angle θ; α is the attenuation coefficient of the surface, which is related to the dielectric constant of the material; is the ambient light noise.

[0012] In the technical solution provided by the present invention, the system includes a light curtain unit, a control unit, an output unit, an external execution unit and an alarm reset unit; the light curtain unit includes a light curtain transmitter and a light curtain receiver relatively arranged in a storage channel, which are used to emit and receive infrared light beams and detect the obstruction of the light beams; the light curtain unit collects the obstruction information of the light beam emitted by the light curtain transmitter by the moving target in real time, and transmits the obstruction information to the control unit, wherein the obstruction information includes the obstruction length, the obstruction position and the obstruction time, and the obstruction light intensity attenuation; the control unit is used to process the data collected by the light curtain unit, and the data analyzes the obstruction length, motion characteristics, obstruction characteristics and light intensity attenuation curve of the light beam, identifies human bodies and objects, and determines their movement directions; the output unit is used to transmit the recognition result of the control unit to the external execution unit to trigger the corresponding control logic; the alarm reset unit is used to detect the alarm, and automatically resets after the alarm event is released, and sends the objects stagnant in the protection area out of the protection area. The system efficiently and accurately identifies human bodies and objects, and can determine their movement directions, thereby avoiding system paralysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 A schematic diagram of a system for separating people and identifying directions based on a light curtain provided in an embodiment of the present invention; Figure 2 A cargo movement diagram provided for an embodiment of the present invention; Figure 3 Human body motion diagram provided by the embodiment of the present invention Figure 4 A comparison diagram of light intensity attenuation curves provided in an embodiment of the present invention.

[0015] Figure numerals: 1 - light curtain unit; 2 - cargo; 3 - human body; 4 - metal attenuation curve; 5 - plastic box attenuation curve; Curve 6 - human body attenuation curve. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] It should be clear that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention are also intended to include plural forms, unless the context clearly indicates other meanings.

[0019] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0020] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0021] Figure 1 A schematic diagram of a system for separating people and identifying directions based on a light curtain provided in an embodiment of the present invention, such as Figure 1 As shown, the system includes: a light curtain unit, a control unit, an output unit, an external execution unit and an alarm reset unit; The light curtain unit includes a light curtain transmitter and a light curtain receiver which are arranged relatively in the storage channel, and are used to transmit and receive infrared light beams and detect the obstruction of the light beams. The light curtain unit collects the obstruction information of the light beam emitted by the light curtain transmitter by the moving target in real time, and transmits the obstruction information to the control unit, wherein the obstruction information includes the obstruction length, obstruction position and obstruction time, and the obstruction light intensity attenuation. The control unit is used to process the data collected by the light curtain unit, and analyze the obstruction length, motion characteristics, obstruction characteristics and light intensity attenuation curve of the light beam to identify the human body and objects, and determine their movement direction. The output unit is used to transmit the recognition result of the control unit to the external execution unit to trigger the corresponding control logic. For example, when it is detected that a human body enters the dangerous area, the output unit triggers the equipment to stop running; when it is detected that an object passes through, the output unit triggers the sorting system to sort. The alarm reset unit is used to detect the alarm, and automatically resets after the alarm event is released, and sends the objects stagnant in the protection area out of the protection area, wherein the control logic includes but is not limited to alarm and equipment stop.

[0022] In the embodiment of the present invention, the scanning plane of the light curtain unit faces the 30-50 cm height area of ​​the storage channel ground; initialization, the length, movement speed and movement direction of the moving target are pre-set in the light curtain unit as legal trigger event features for allowing passage.

[0023] In the embodiment of the present invention, the control unit analyzes the occlusion length, motion characteristics, occlusion characteristics and light intensity attenuation curve of the light beam through a preset algorithm to determine whether the type of the moving target is a human body or an object; and extracts key parameters by fitting the light intensity attenuation curve through the least squares method, including: initial light intensity I 0 , used to reflect the reflectivity of the surface of the object. The initial light intensity of the metal tray is 100-200μW, and the initial light intensity of the human body is 10-30μW, that is, the initial light intensity of the metal tray is greater than that of the human body; the surface attenuation coefficient α is used to characterize the absorption characteristics of the material. The attenuation coefficient of human skin is 0.02-0.05, and the attenuation coefficient of the plastic box is 0.03-0.07, that is, the attenuation coefficient of human skin is greater than that of the plastic box; the human step frequency is 0.8-1.4Hz, and the interval time distribution of the corresponding light intensity occlusion event is 1.2-2.5s Poisson distribution. The mechanical movement of the object is usually uniform linear motion, that is, fixed occlusion interval. If the occlusion length changes intermittently, the occlusion time interval obeys the 1.2-2.5s Poisson distribution, and the occlusion light intensity decays exponentially, then the moving target is the human body; if the occlusion length remains unchanged or changes continuously, the occlusion time interval is a fixed interval, and the occlusion light intensity decays linearly, then the moving target is an object.

[0024] In the embodiment of the present invention, Figure 2As shown, the arrow points to the direction of light from the light curtain transmitter to the light curtain receiver. When the moving target is a regular cargo, the shielding length and shielding interval are fixed; Figure 3 As shown, the arrow points to the direction of light from the light curtain transmitter to the light curtain receiver. When the moving target is a human body, the interval is Poisson distributed in a range of 1.2-2.5s due to the occlusion of the human leg step frequency.

[0025] In an embodiment of the present invention, the control unit determines the movement direction of the mobile target through a preset algorithm based on the light beam blocking sequence and blocking time; the movement direction is determined by the following rules: if the light beam blocking sequence conforms to the preset movement direction, it is determined to be the forward direction; if the light beam blocking sequence does not conform to the preset movement direction, it is determined to be the backward direction.

[0026] In an embodiment of the present invention, the output unit transmits the recognition result of the control unit to the external execution unit, triggering the corresponding control logic, wherein the recognition result includes the type of the moving target and the direction of the moving target; when the external execution unit triggers the control logic to enter the alarm state, after the alarm event is lifted, the alarm reset unit is immediately started until the object stagnant in the protection area leaves the protection area.

[0027] In the embodiment of the present invention, the interval time t of light beam blocking caused by alternating movements of the legs when a person walks obeys a Poisson distribution with a parameter λ, and its expression is: ; in , T is the average step frequency, which is 1.2-2.5s.

[0028] In the embodiment of the present invention, the light intensity attenuation curve is defined as a function of the light intensity of the light beam reflected from the object surface and propagated to the light curtain receiver after time t, which is expressed as: ; Among them, I 0 is the initial light intensity; R(θ) is the reflectivity of the object surface, which is related to the incident angle θ; α is the attenuation coefficient of the surface, which is related to the dielectric constant of the material; is the ambient light noise.

[0029] In the embodiment of the present invention, Figure 4 As shown, curve 4 is the metal attenuation curve; curve 5 is the plastic box attenuation curve; curve 6 is the human body attenuation curve; metal light intensity attenuation curve (curve 4): τ≈1.1ms, I 0 ≈120μW, the waveform is smooth and linearly decays; Plastic box light intensity decay curve (curve 5): τ≈800μs, I 0 ≈55μW, showing a moderately slow decay; Human body light intensity decay curve (curve 6): τ≈380μs, I0 ≈15μW, exponentially decaying with high-frequency vibration noise.

[0030] In the embodiment of the present invention, the scenario is described as follows: in a storage channel, personnel and heavy goods flow together, and it is necessary to accurately distinguish between personnel and goods, and determine their direction of movement to ensure personnel safety and work efficiency; at the same time, after the alarm is triggered and the alarm event is lifted, the goods stagnant in the protection area must be transported away by a conveyor belt due to their weight.

[0031] Implementation steps: The light curtain unit collects the light beam blocking information in real time. The control unit analyzes the light beam blocking length and blocking characteristics, and the light intensity attenuation curve to determine the type of moving target. The control unit determines the moving direction of the moving target based on the blocking sequence and blocking time of the light beam. If the moving target is a human body, the output unit triggers an alarm. After the alarm event is lifted, the alarm reset starts until the stopped goods are sent out of the protection area; if the moving target is an object, the output unit triggers the sorting system for sorting.

[0032] The characteristics of the system in the present invention are as follows: direction recognition, by analyzing the blocking sequence and blocking time of the light beam, the moving direction of the moving target can be accurately determined; fast response: the response speed of the light curtain unit is extremely fast, and the recognition can be completed within milliseconds; strong anti-interference ability: the light curtain unit is not affected by ambient light and background interference, and is suitable for complex environments. Low cost: the light curtain unit has a low cost and is suitable for large-scale applications. The system in the present invention can efficiently and accurately identify human bodies and objects, and determine their direction of movement, and has an alarm reset function, which automatically resets when the system fails. It has the advantages of high precision, fast response, strong anti-interference ability, and low cost. It is suitable for storage channels, and is also suitable for scenes such as automated sorting systems and safety protection areas, and has broad application prospects.

[0033] In the technical solution provided by the present invention, the system includes a light curtain unit, a control unit, an output unit, an external execution unit and an alarm reset unit; the light curtain unit includes a light curtain transmitter and a light curtain receiver relatively arranged in a storage channel, which are used to emit and receive infrared light beams and detect the obstruction of the light beams; the light curtain unit collects the obstruction information of the light beam emitted by the light curtain transmitter by the moving target in real time, and transmits the obstruction information to the control unit, wherein the obstruction information includes the obstruction length, the obstruction position and the obstruction time, and the obstruction light intensity attenuation; the control unit is used to process the data collected by the light curtain unit, and the data analyzes the obstruction length, motion characteristics, obstruction characteristics and light intensity attenuation curve of the light beam, identifies human bodies and objects, and determines their movement directions; the output unit is used to transmit the recognition result of the control unit to the external execution unit to trigger the corresponding control logic; the alarm reset unit is used to detect the alarm, and automatically resets after the alarm event is released, and sends the objects stagnant in the protection area out of the protection area. The system efficiently and accurately identifies human bodies and objects, and can determine their movement directions, thereby avoiding system paralysis.

[0034] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A system for separating people and identifying directions based on a light curtain, characterized in that: The system comprises: a light curtain unit, a control unit, an output unit, an external execution unit and an alarm reset unit; The light curtain unit includes a light curtain transmitter and a light curtain receiver which are relatively arranged in the storage channel, and are used for emitting and receiving infrared light beams and detecting the obstruction of the light beams. The light curtain unit collects the obstruction information of the light beam emitted by the light curtain transmitter by the moving target in real time, and transmits the obstruction information to the control unit, wherein the obstruction information includes the obstruction length, obstruction position and obstruction time, and the obstruction light intensity attenuation. The control unit is used for processing the data collected by the light curtain unit, analyzing the obstruction length, motion characteristics, obstruction characteristics and light intensity attenuation curve of the light beam, identifying human bodies and objects, and determining their movement directions. The output unit is used for transmitting the recognition result of the control unit to the external execution unit to trigger the corresponding control logic. The alarm reset unit is used for detecting the alarm, and automatically resets after the alarm event is released, so as to send the objects stagnant in the protection area out of the protection area.

2. The system according to claim 1, characterized in that The scanning plane of the light curtain unit faces the area at a height of 30-50 cm from the floor of the storage passage; during initialization, the length, movement speed and movement direction of the moving target are pre-set in the light curtain unit as legal trigger event features for allowing passage.

3. The system according to claim 1, characterized in that The control unit analyzes the occlusion length, motion characteristics, occlusion characteristics and light intensity attenuation curve of the light beam through a preset algorithm to determine whether the type of the moving target is a human body or an object; the light intensity attenuation curve is fitted through the least squares method to extract key parameters, including: initial light intensity I0, which is used to reflect the surface reflectivity of the object. The initial light intensity of the metal tray is 100-200μW, and the initial light intensity of the human body is 10-30μW, that is, the initial light intensity of the metal tray is greater than the initial light intensity of the human body; the surface attenuation coefficient α, which is used to characterize the absorption characteristics of the material. The attenuation coefficient of human skin is 0.02-0.05, and the attenuation coefficient of the plastic box is 0.01-0.

03. The coefficient is 0.03-0.07, that is, the attenuation coefficient of human skin is greater than that of the plastic box; the human step frequency is 0.8-1.4Hz, and the interval time distribution of the corresponding light intensity occlusion event is 1.2-2.5s Poisson distribution. The mechanical movement of an object is usually uniform linear motion, that is, a fixed occlusion interval. If the occlusion length changes intermittently, the occlusion time interval obeys the 1.2-2.5s Poisson distribution, and the occlusion light intensity decays exponentially, then the moving target is a human body; if the occlusion length remains unchanged or changes continuously, the occlusion time interval is a fixed interval, and the occlusion light intensity decays linearly, then the moving target is an object.

4. The system according to claim 1, characterized in that The control unit determines the movement direction of the mobile target through a preset algorithm according to the light beam blocking sequence and blocking time; the movement direction is determined by the following rules: if the light beam blocking sequence conforms to the preset movement direction, it is determined to be a forward direction; if the light beam blocking sequence does not conform to the preset movement direction, it is determined to be a backward direction.

5. The system according to claim 1, characterized in that The output unit transmits the recognition result of the control unit to the external execution unit, triggering the corresponding control logic, wherein the recognition result includes the type of the moving target and the direction of the moving target; when the external execution unit triggers the control logic to enter the alarm state, after the alarm event is lifted, the alarm reset unit is immediately started until the object that is stationary in the protection area leaves the protection area.

6. The system according to claim 3, characterized in that When a person walks, the alternating movement of the legs causes the beam blocking interval time t to follow the Poisson distribution with parameter λ, and its expression is: ； in , T is the average step frequency, which is 1.2-2.5s.

7. The system according to claim 3, characterized in that The light intensity attenuation curve is defined as the function of the light intensity that changes with time after the light beam is reflected from the object surface and propagated to the light curtain receiver after time t. Its expression is: ； Among them, I0 is the initial light intensity; R(θ) is the reflectivity of the object surface, which is related to the incident angle θ; α is the attenuation coefficient of the surface, which is related to the dielectric constant of the material; is the ambient light noise.

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