EP-4256517-B1 - SYSTEMS AND METHODS FOR TEMPERATURE DETERMINATION

EP4256517B1EP 4256517 B1EP4256517 B1EP 4256517B1EP-4256517-B1

Inventors

LU, Huachao
LIU, Su
XU, Diquan
PU, TAO
WEI, Ziwei

Dates

Publication Date: 20260513
Application Date: 20210901

Claims (15)

A system, comprising: at least one storage device including a set of instructions; and at least one processor in communication with the at least one storage device, wherein when executing the set of instructions, the at least one processor is configured to cause the system to: obtain a visible image and a thermal image from an image capture device, the visible image including at least one subject; for each of the at least one subject, determine first location information associated with a face of the subject in the visible image; determine a distance between the subject and the image capture device based on the visible image, wherein the at least one processor is configured to cause the system to: determine a visible size associated with at least one reference object associated with the subject in the visible image; and determine the distance between the subject and the image capture device based on the visible size associated with the at least one reference object in the visible image and a physical size associated with the at least one reference object; determine second location information associated with the face in the thermal image based on the first location information associated with the face; and determine a temperature of the subject based on the second location information associated with the face and the distance between the subject and the image capture device; characterised in that the at least one processor is further configured to cause the system to: determine a reference parameter associated with the subject the reference parameter including at least one of the distance between the subject and the image capture device, a moving speed of the subject, or a moving direction of the subject; and determine a priority order of the at least one subject based on at least one reference parameter corresponding to the at least one subject respectively.
The system of claim 1, wherein the visible size includes a visible distance between pupil points of the subject in the visible image.
The system of claim 1, wherein the at least one reference object includes pupil points of the subject, a marker stick to the subject, or an environmental marker.
The system of any one of claims 1-3, wherein to determine second location information associated with the face in the thermal image based on the first location information associated with the face, the at least one processor is configured to cause the system to: determine the second location information associated with the face in the thermal image based on the first location information associated with the face and a location relationship between a visible capture unit used to capture the visible image and a thermal capture unit used to capture the thermal image included in the image capture device.
The system of any one of claims 1-4, wherein to determine a temperature of the subject based on the second location information associated with the face and the distance between the subject and the image capture device, the at least one processor is configured to cause the system to: determine gray values associated with the face in the thermal image based on the second location information; and determine the temperature of the subject based on the gray values associated with the face in the thermal image and the distance between the subject and the image capture device.
The system of any one of claims 1-5, wherein the at least one processor is configured to cause the system further to: determine whether the temperature of the subject is within a reference temperature range; in response to determining that the temperature of the subject is within the reference temperature range, cause a display device to display information associated with the subject; and in response to determining that the temperature of the subject is not within the reference temperature range, not cause the display device to display the information associated with the subject.
The system of claim 6, wherein the displayed information associated with the subject includes at least one of a bounding box of the face, the temperature of the subject, the distance between the subject and the image capture device, or a location of the subject.
The system of claim 6, wherein to cause the display device to display information associated with the subject, the at least one processor is configured to cause the system further to: determine whether the temperature of the subject is within a normal temperature range; in response to determining that the temperature of the subject is within the normal temperature range, cause the display device to display the information associated with the subject in a first mode; in response to determining that the temperature of the subject is not within the normal temperature range, cause the display device to display the information associated with the subject in a second mode.
The system of claim 8, wherein the at least one processor is configured to cause the system further to: in response to determining that the temperature of the subject is not within the reference temperature range or the normal temperature range, perform at least one additional temperature determination operation.
The system of any one of claims 1-9, wherein to determine a priority order of the at least one subject based on at least one reference parameter corresponding to the at least one subject respectively, the at least one processor is configured to cause the system to: in response to determining that the reference parameter of the subject satisfies a condition, determine the priority order; wherein the condition includes that the distance between the subject and the image capture device is smaller than a distance threshold, the moving speed of the subject is larger than a speed threshold, or the moving direction of the subject is a direction away from the image capture device.
The system of claim 5, wherein to determine the temperature of the subject based on the gray values associated with the face in the thermal image and the distance between the subject and the image capture device, the at least one processor is configured to cause the system to: obtain a current shell temperature of the subject before compensation based on the gray values associated with the face in the thermal image; obtain a current shell temperature of the subject after compensation by inputting the current shell temperature of the subject before compensation and the distance between the subject and the image capture device into a trained regression model; obtain a current environmental temperature of an environment where the image capture device is located; retrieve a core temperature corresponding to the current shell temperature of the subject after compensation based on the current environmental temperature and a shell-core temperature conversion table; obtain a current core temperature of the subject by compensating the core temperature based on a relationship between the current environmental temperature and environmental temperatures in the shell-core temperature conversion table.
The system of claim 11, wherein to obtain the current core temperature of the subject by compensating the core temperature based on the relationship between the current environmental temperature and environmental temperatures in the shell-core temperature conversion table, the at least one processor is configured to cause the system to: obtain a first environmental temperature and a second environmental temperature that are closest to the current environmental temperature, and a first shell temperature and a second shell temperature that are closest to the current shell temperature of the subject after compensation in the shell-core temperature conversion table; calculate a first weight of an environmental temperature that a difference between the current environmental temperature and the first environmental temperature accounts for a difference between the first environmental temperature and the second environmental temperature; calculate a second weight of the environmental temperature that a difference between the current environmental temperature and the second environmental temperature accounts for a difference between the first environmental temperature and the second environmental temperature; calculate a first core temperature and a second core temperature corresponding to the first shell temperature and the second shell temperature under the current environmental temperature based on the first weight and the second weight of the environmental temperature, respectively; calculate a first weight of a shell temperature that a difference between the current shell temperature and the first shell temperature accounts for a difference between the first shell temperature and the second shell temperature; calculate a second weight of the shell temperature that a difference between the current shell temperature and the second shell temperature accounts for the difference between the first shell temperature and the second shell temperature; and calculate the current core temperature of the subject corresponding to the first core temperature and the second core temperature under the current shell temperature based on the first weight of the shell temperature and the second weight of the shell temperature.
A method implemented on a computing device having at least one processor, at least one storage medium, and a communication platform connected to a network, the method comprising: obtaining a visible image and a thermal image from an image capture device, the visible image including at least one subject; for each of the at least one subject, determining first location information associated with a face of the subject in the visible image; determining a distance between the subject and the image capture device based on the visible image, including: determining a visible size associated with at least one reference object associated with the subject in the visible image; and determining the distance between the subject and the image capture device based on the visible size associated with the at least one reference object in the visible image and a physical size associated with the at least one reference object; determining second location information associated with the face in the thermal image based on the first location information associated with the face; and determining a temperature of the subject based on the second location information associated with the face and the distance between the subject and the image capture device; characterised in that the method further comprising : determining a reference parameter associated with the subject, the reference parameter including at least one of the distance between the subject and the image capture device, a moving speed of the subject, or a moving direction of the subject; and determining a priority order of the at least one subject based on at least one reference parameter corresponding to the at least one subject respectively.
The method of claim 13, wherein the visible size includes a visible distance between pupil points of the subject in the visible image.
A non-transitory computer readable medium, comprising executable instructions that, when executed by at least one processor, directs the at least one processor to perform a method, the method comprising: obtaining a visible image and a thermal image from an image capture device, the visible image including at least one subject; for each of the at least one subject, determining first location information associated with a face of the subject in the visible image; determining a distance between the subject and the image capture device based on the visible image, including: determining a visible size associated with at least one reference object associated with the subject in the visible image; and determining the distance between the subject and the image capture device based on the visible size associated with the at least one reference object in the visible image and a physical size associated with the at least one reference object; determining second location information associated with the face in the thermal image based on the first location information associated with the face; and determining a temperature of the subject based on the second location information associated with the face and the distance between the subject and the image capture device; characterised in that the method further comprising : determining a reference parameter associated with the subject, the reference parameter including at least one of the distance between the subject and the image capture device, a moving speed of the subject, or a moving direction of the subject; and determining a priority order of the at least one subject based on at least one reference parameter corresponding to the at least one subject respectively.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202110042528.5 filed on January 13, 2021. TECHNICAL FIELD The present disclosure generally relates to thermal imaging, and in particular, to systems and methods for determining a temperature of a subject. BACKGROUND A temperature of a subject (e.g., a person) may be determined based on gray values associated with the subject in a thermal image acquired by a thermal capture device (e.g., a thermal camera). However, thermal radiation of the subject may be attenuated as a distance between the thermal capture device and the subject increases, accordingly, the larger the distance between the thermal capture device and the subject is, the lower the temperature of the subject determined based on the thermal image may be, which can't accurately indicate an actual temperature of the subject. Therefore, it is desirable to provide systems and methods for determining a temperature of a subject accurately with distance taken into consideration. Relevant prior art can be found in patent publications KR102161477B1, CN111337142A and US2009/136093A1. SUMMARY OF THE INVENTION The invention is defined in the appended set of claims. SUMMARY OF THE DISCLOSURE According to one aspect of the present disclosure, a system may be provided. The system may include at least one storage device including a set of instructions; and at least one processor in communication with the at least one storage device, wherein when executing the set of instructions, the at least one processor may be configured to cause the system to: obtain a visible image and a thermal image from an image capture device, the visible image including at least one subject; for each of the at least one subject, determine first location information associated with a face of the subject in the visible image; determine a distance between the subject and the image capture device based on the visible image; determine second location information associated with the face in the thermal image based on the first location information associated with the face; and determine a temperature of the subject based on the second location information associated with the face and the distance between the subject and the image capture device. To determine a distance between the subject and the image capture device based on the visible image, the at least one processor is configured to cause the system to: determine a visible size associated with at least one reference object associated with the subject in the visible image; and determine the distance between the subject and the image capture device based on the visible size associated with the at least one reference object in the visible image and a physical size associated with the at least one reference object. In some embodiments, the at least one reference object may include pupil points of the subject, a marker stick to the subject, or an environmental marker. In some embodiments, to determine second location information associated with the face in the thermal image based on the first location information associated with the face, the at least one processor may be configured to cause the system to: determine the second location information associated with the face in the thermal image based on the first location information associated with the face and a location relationship between a visible capture unit used to capture the visible image and a thermal capture unit used to capture the thermal image included in the image capture device. In some embodiments, to determine a temperature of the subject based on the second location information associated with the face and the distance between the subject and the image capture device, the at least one processor may be configured to cause the system to: determine gray values associated with the face in the thermal image based on the second location information; and determine the temperature of the subject based on the gray values associated with the face in the thermal image and the distance between the subject and the image capture device. In some embodiments, the at least one processor may be configured to cause the system further to: determine whether the temperature of the subject is within a reference temperature range; in response to determining that the temperature of the subject is within the reference temperature range, cause a display device to display information associated with the subject; and in response to determining that the temperature of the subject is not within the reference temperature range, not cause the display device to display information associated with the subject. In some embodiments, the displayed information associated with the subject may include at least one of a bounding box of the face, the temperature of the subject, the distance between the subject and the image capture device, or a location of the subject. In some embodiments, to cause the display