CN-115810211-B - Thermal comfort evaluation method based on infrared thermal imaging technology

CN115810211BCN 115810211 BCN115810211 BCN 115810211BCN-115810211-B

Abstract

The invention provides a thermal comfort evaluation method based on an infrared thermal imaging technology, which comprises the steps of acquiring infrared thermal imaging data of a target object in real time, determining skin temperature data of a region of interest of the face of the target object based on the infrared thermal imaging data, calculating a thermal sensation grade through the skin temperature data and combining a thermal sensation evaluation model, and adjusting temperature setting of target equipment according to the thermal sensation grade. The invention only adopts the skin temperature of a single part (such as the skin temperature of the face) to evaluate the heat sensation, is simple and convenient, has higher accuracy, does not need the user to wear intelligent equipment for acquiring the skin temperature, and acquires the skin temperature of the face of the user directly in a non-contact mode.

Inventors

LIU WEIWEI
TIAN XIAOYU

Assignees

中南大学

Dates

Publication Date: 20260505
Application Date: 20221128

Claims (5)

1. A thermal comfort evaluation method based on infrared thermal imaging technology, characterized in that the method comprises the following steps: s1, acquiring infrared thermal imaging data of a target object in real time; s2, determining skin temperature data of a region of interest of the face of the target object based on the infrared thermal imaging data; s3, calculating a thermal sensation grade by combining the skin temperature data with a thermal sensation evaluation model; s4, adjusting the temperature setting of the target equipment according to the thermal sensation level; The method comprises the steps that step S1, according to a detection time interval, infrared thermal imaging data of a face of a target object are acquired through infrared thermal imaging equipment arranged on the target equipment within an acquisition range; Step S2 comprises the steps of determining a face region of interest based on a current season and a face region priority sequence corresponding to the season, extracting a temperature measurement value of the face region of interest from the infrared thermal imaging data, correcting the temperature measurement value to obtain a corrected temperature measurement value in consideration of the influence of the ambient temperature, and calculating skin temperature data of the face region of interest through the corrected temperature measurement value; The acquisition range is determined by the following expression: ; ; Wherein, the Representing a minimum distance of the face of the target object from the infrared thermal imaging device; Representing the height of a target object; 、 representing the horizontal and vertical field views of the infrared thermal imaging device, respectively; representing a maximum distance between the face of the target object and the infrared thermal imaging device; 、 Representing pixel values of the infrared thermal imaging device; Skin temperature data of the region of interest of the face is calculated by the following formula: ; Wherein, the Skin temperature data representing a region of interest of the face; Represents the spectral transmittance of the atmosphere; Representing the shooting angle of the infrared thermal imaging equipment and the refractive index coefficient of the material of the object; is the included angle between the surface radiation normal of the target object and the observation direction; 、 respectively representing the target visual area corresponding to the minimum space opening angle of the infrared thermal imaging equipment and the distance between the target visual area and the target object; representing the shooting distance of the infrared thermal imaging equipment; Representing the ambient temperature around the target object; represents the atmospheric temperature; Representing the temperature measurement before correction, or using the temperature measurement after correction; Representing a constant determined from planck's law integral; step S3 comprises comparing skin temperature data of the region of interest with thresholds of different thermal sensation levels in the thermal sensation evaluation model to obtain the thermal sensation levels, wherein the skin temperature data is corrected by the following formula when the thermal sensation evaluation model is constructed: ; In the formula, , Respectively indicate the previous temperature And the latter temperature The corresponding difference value is equal to the actual measured value minus the calibration value; The skin temperature value and the actual measured value corrected at the i-th time are indicated by C, respectively.
2. The thermal comfort evaluation method based on infrared thermal imaging technology according to claim 1, wherein the temperature measurement value is corrected by the following formula: ; Wherein, the Representing the corrected temperature measurement; 、、、 representing the correction coefficient; Representing a temperature measurement prior to correction; representing the ambient temperature around the target object.
3. The method for evaluating thermal comfort based on infrared thermal imaging technology according to any one of claims 1 to 2, wherein step S4 comprises: if the current thermal sensation level is hot neutral, not adjusting the temperature setting of the target equipment; if the current heat sensation level is cold, the temperature setting of the target equipment is increased; And if the current heat sensation level is heat, regulating down the temperature setting of the target equipment.
4. A storage medium containing instructions for performing the method of any one of claims 1-3.
5. A thermal comfort evaluation system based on infrared thermal imaging technology, characterized in that a method according to any one of claims 1-3 is performed, the system comprising a mobile terminal and a target device, wherein: The mobile terminal performs the steps of: Determining skin temperature data of a region of interest of a face of a target object based on the infrared thermal imaging data; calculating a thermal sensation grade according to the skin temperature data and the thermal sensation evaluation model; Generating a temperature adjustment instruction for the target device according to the thermal sensation level; the target device includes: the infrared thermal imaging equipment is used for acquiring infrared thermal imaging data of the target object in real time; A wireless microcontroller for transmitting the infrared thermal imaging data to the mobile terminal and receiving the thermal sensation level and the temperature adjustment instruction transmitted by the mobile terminal; and the display screen is used for displaying the skin temperature data of the region of interest of the face and the thermal sensation level.

Description

Thermal comfort evaluation method based on infrared thermal imaging technology Technical Field The invention relates to the technical field of thermal comfort evaluation, in particular to a thermal comfort evaluation method based on an infrared thermal imaging technology. Background With the improvement of living standard, the demands of people on indoor hot environments are no longer satisfied for cooling in summer and heating in winter, and more tend to be a good comfortable and healthy environment. The good health and comfortable hot environment is not only beneficial to the health of human bodies, but also can effectively improve the working efficiency. Meanwhile, the indoor thermal environment is controlled at a comfortable level, which is also of great significance to building energy saving research. Currently, methods used in air conditioning systems to create comfortable indoor environments are mainly empirical, based on PMV models and user feedback thermal preferences. The empirical method is to set the indoor set temperature according to the standard GB50019-2015 of the design specification of heating ventilation and air conditioning of industrial buildings. The indoor comfortable temperature range in winter is 18-24 ℃, and the indoor comfortable temperature range in summer is 25-28 ℃. The PMV model is used to predict the thermal sensation of a population in a steady state environment. The PMV value is within the range of-0.5 to 0.5, so that 80% of people feel hot and comfortable to the hot environment of the air conditioner. However, a great deal of research has found that PMV does not necessarily truly reflect human thermal comfort. For example, dear and Brager recognize that human thermal comfort is not only related to ambient temperature, radiant temperature, relative humidity, wind speed, etc., but is also affected by physiological heat exercise, psychological expectations, windowing, etc. Huizer et al conducted on-site investigations of 215 office environments in the United states, canada and France, and found that only 11% of the office environments met the thermal comfort of 80% of the population. On the other hand, the PMV model needs to collect parameters of indoor air temperature, relative humidity, radiation temperature, garment thermal resistance, wind speed and human metabolic rate in real time. The acquisition parameters are more in the practical application process. The user feeds back the thermal preference, i.e. the user actively inputs the thermal preference into the air conditioning system. The system adjusts the indoor air temperature and humidity according to the thermal preference fed back by the user. This approach better reflects the individual thermal comfort level compared to the PMV model. There are limitations in that users need to input a large number of thermal preferences, and they can only be targeted to specific users and cannot be widely applied to other users. Aiming at the problems in the prior art, the invention provides a thermal comfort evaluation method based on an infrared thermal imaging technology. Disclosure of Invention In order to solve the problems of the prior art, the invention provides a thermal comfort evaluation method based on an infrared thermal imaging technology, which comprises the following steps: s1, acquiring infrared thermal imaging data of a target object in real time; s2, determining skin temperature data of a region of interest of the face of the target object based on the infrared thermal imaging data; s3, calculating a thermal sensation grade by combining the skin temperature data with a thermal sensation evaluation model; And S4, adjusting the temperature setting of the target equipment according to the thermal sensation level. According to one embodiment of the invention, step S1 comprises acquiring the infrared thermal imaging data of the face of the target object through an infrared thermal imaging device arranged on the target device in an acquisition range according to a detection time interval. According to one embodiment of the invention, the acquisition range is determined by the following expression: ; ; Wherein, the Representing a minimum distance of the face of the target object from the infrared thermal imaging device; Representing the height of a target object; 、 representing the horizontal and vertical field views of the infrared thermal imaging device, respectively; representing a maximum distance between the face of the target object and the infrared thermal imaging device; 、 Representing pixel values of the infrared thermal imaging device. According to one embodiment of the present invention, step S2 comprises: determining a face region of interest based on the current season and the face region priority order corresponding to the season; Extracting a temperature measurement of the facial region of interest from the infrared thermal imaging data; Correcting the temperature measured value in consideration of the