Patent Publication Number: US-2005123182-A1

Title: Temperature sensor

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This present invention relates to a temperature sensor, especially to a temperature sensor for automatically sensing a temperature profile of a target surface and for judging whether a high-temperature area, having a temperature higher than a predetermined temperature, of the target surface is a major area.  
      2. Description of the Prior Art  
      There are many different kinds of temperature sensors of the prior art for sensing body temperature, such as different kinds of mercury thermometers, heat-sensitive resistor thermometers, liquid crystal thermometers, infrared thermometers . . . etc. The most convenient kind to use is an infrared thermometer which senses a temperature profile without touching a target surface. Depending on functions of different infrared thermometers, a local or a whole temperature profile of the target surface can be detected in a few seconds and only in a distance of several centimeters or meters.  
      An infrared temperature sensor of the prior art utilizes the property of an infrared ray to sense temperature without directly touching a whole or a local part of the human body, and it switches the temperature profile into an electric signal which is transmitted to a display module, then the display module shows the temperature profile in gray or colorful shades. This kind of infrared temperature sensor can be conveniently applied in places with heavy people-circulation and rapid motion, such as in airports, schools, department stores, shopping centers, or hospitals. At these places infrared temperature sensors are used to detect human temperature.  
      An infrared temperature sensor of the prior art displays the sensing result in an image form on the display module; however, a trained person is needed to judge whether a high-temperature area of a person&#39;s exteriority is higher than a predetermined temperature, or that person has what is called a “fever”. As factors like environment, types of clothing, and all kinds of personal accessories often influence the obtained result, it makes the situation complicated and difficult for the trained person to judge whether a person has a fever, thus diminishing the efficiency of the infrared sensor and the accuracy of the judgments made. For example, in a situation that a person just basking in the sun outdoors is sensed by an infrared temperature sensor, the infrared temperature sensor would show that the temperature of the person&#39;s hair to be higher than a normal state and mislead spectators to conclude that the person has a fever, whereas the person&#39;s hair simply absorbs too much radiation of sunlight. In addition, to judge whether the high-temperature area of the person&#39;s exteriority is higher than a predetermined temperature from the data shown on the display module needs an experienced person to make a decision, so the costs of labor will be increased. Thus, it is necessary to provide a temperature sensor for automatically sensing in order to reduce the costs of labor and optimize the efficiency.  
     SUMMARY OF THE INVENTION  
      One objective of the present invention is to provide a temperature sensor for sensing a temperature profile of a target surface and to judge whether a high-temperature area, having a temperature higher than a predetermined temperature, of the target surface is a major area. Another objective of the present invention is to provide a temperature sensor for automatically judging whether the high-temperature area, having a temperature higher than a predetermined temperature, of the target surface is a major area, in order to optimize monitoring efficiency and reduce the costs of labor.  
      The present invention provides a temperature sensor for sensing a temperature profile of a target surface and judges whether a high-temperature area, having a temperature higher than a predetermined temperature, of the target surface is a major area. The temperature sensor comprises an image capturing module, an image processing module, an image database, and a comparison module. An image capturing module is used for measuring the temperature profile of the target surface and for capturing a beat image of the target surface. An image processing module is used for filtering the heat image of the target surface according to the temperature profile and labelling the high-temperature area. An image database is used for storing plural images of the major areas. A comparison module, based on a figure recognition technology, is used for comparing an image of the high-temperature area with the image of the major area stored in the image database and for deciding whether the high-temperature area is the major areas.  
      The temperature sensing method of the present invention can automatically determine whether a high-temperature area, having a temperature higher than a predetermined temperature, of the target surface is a major area, with no trained persons to make the judgment; thus, the present invention can speed up the monitoring process and reduce the costs of labor. Moreover, the temperature sensing method of the present invention compares only the images of major areas, so that factors like environment, types of clothing and all kinds of personal accessories tending to influence judgment can be averted.  
      The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE APPENDED DRAWINGS  
       FIG. 1  is a schematic diagram of the temperature sensor of the present invention.  
       FIG. 2  is a schematic diagram utilizing the temperature sensor in  FIG. 1  for sensing the temperature profile of the target surface.  
       FIG. 3A  is a schematic diagram of a first image of the major area stored in the image database as illustrated in  FIG. 1   
       FIG. 3B  is a schematic diagram of a second image of the major area stored in the image database as illustrated in  FIG. 1 .  
       FIG. 4  is a block diagram of another embodiment of the temperature sensor of the present invention  
       FIG. 5  is a flowchart of the temperature sensing method of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to  FIG. 1  and  FIG. 2 ,  FIG. 1  is a schematic diagram of the temperature sensor  10  of the present invention, and  FIG. 2  is a schematic diagram utilizing the temperature sensor  10  in  FIG. 1  for sensing the temperature profile of the target surface. The temperature sensor  10  of the present invention comprises an image capturing module  20 , an image processing module  30 , an image database  40 , and a comparison module  50 . The temperature sensor  10  senses a temperature profile of a target surface and judges whether a high-temperature area, having a temperature higher than a predetermined temperature, of the target surface is a major area. In this embodiment, the target surface is a person&#39;s head; please refer to  FIG. 1  and  FIG. 2 . An image capturing module  20  measures the temperature profile of the target surface and captures a heat image of the target surface with infrared image sensing technology. In the embodiment as illustrated in  FIG. 2 , the heat image  12  is a woman&#39;s head. The heat image  12  is composed of a plurality of pixels, wherein each pixel can be displayed in a color corresponding to the temperature at each location of the target surface.  
      An image processing module  30  filters the heat image  12  of the target surface according to the temperature profile and labels the high-temperature area. For example, the high-temperature area, which has a temperature higher than a predetermined temperature, of the temperature profile is labeled with various colors.  
      Referring to  FIG. 3A  and  FIG. 3B ,  FIG. 3A  is a schematic diagram of a first image of the major area  42   a  stored in the image database  40  as illustrated in  FIG. 1 , and  FIG. 3B  is a schematic diagram of a second image of the major area  42   b  stored in the image database  40  as illustrated in.  FIG. 1 . The image database  40  stores the images of the major areas  42  (as illustrated in  FIG. 1 ). In the embodiment as illustrated in  FIG. 2 , the major areas  16  represents real surface areas of a human body including a forehead, two cheeks, temples, and the areas in the vicinity of the mouth where a high temperature would indicate that the person might have a fever. The first image  42   a  and the second image  42   b  respectively illustrate images of different major areas  16  stored in the image database  40 .  
      The comparison module  50 , based on a figure recognition technology, compares the images of the high-temperature areas of the target surface with the images of the major areas  42  stored in the image database  40 , and it then decides whether the high-temperature area of the target surface is the major area  16 . The comparison module  50  compares each pixel of the image of the high-temperature area with each pixel of the image of the major areas  42 , wherein, the image processing  30  has already filtered the heat images  12  of the target surface according to the temperature profile and has labelled the high-temperature area, of which the temperature is higher than a predetermined temperature, with various colors, in the embodiment as illustrated in  FIG. 2 , a matching value is obtained after the comparison module  50  evaluates the similarity between a pixel of the image of the high-temperature area and a pixel of the image of the major areas  42   a , where the matching value is a quantitative measurement of the similarity between the two pixels in, for instance, colors, gray scale or other characteristics of pixels. When the sum of the matching values exceeds a critical value, the high-temperature area is judged as the major area  16 . As illustrated in  FIG. 3A  and  FIG. 3B , the image database  40  records many different images of the major areas  42 , wherein the major areas  16  vary with different types of human body features such as long hair, short hair, bald, and hat-wearing.  
      Thus, when a place with heavy people-circulation and rapid motion, such as airports, schools, department stores, shopping centers or hospitals, makes use of the temperature sensor  10  of the present invention to sense human temperature, the temperature sensor  10  can automatically judge whether the high-temperature area of the target surface is higher than a predetermined temperature, so that not only the accuracy of the judgment is improved, but also the monitoring efficiency. Furthermore, the present invention doesn&#39;t require a trained person to compare or monitor the sensing result to decide whether the high-temperature area of the target surface is higher than a normal state, such that it speeds up the entire process and reduces the costs of labor.  
      Besides, the temperature sensor  10  of the present invention judges by comparing the images of the major area  16 , hence erroneous judgment can be prevented. For example, in a situation of the prior art where a person walks indoors from outside wearing a hat in a dark color, because the hat has absorbed too much heat of sunlight, the raise in the temperature of the hat may lead to the erroneous judgment that the person&#39;s body temperature is higher than a predetermined temperature. The present invention, however, judges by comparing the temperatures of the major areas  16 , so as to prevent erroneous judgment that may be caused by factors like environment, clothing types and all kinds of personnel accessories.  
      Referring to  FIG. 4 ,  FIG. 4  is a block diagram of another embodiment of the temperature sensor  22  of the present invention. The difference between the temperature sensor  22  and the temperature sensor  10  illustrated in  FIG. 1 , lies in that the temperature sensor  22  further comprises an alarm module  52 , and a display module  54 .  
      The alarm module  52  sends out an alarm signaling that the high-temperature area is the major area when the comparison module  50  judges that the high-temperature area, having a temperature higher than a predetermined temperature, of the target surface is the major area. The display module  54  displays the images of the high-temperature areas.  
      Furthermore, the temperature sensor  22  of the present invention not only automatically judges whether the high-temperature area of the target surface is higher than a predetermined temperature but also automatically sends an alarm to signal that the temperature of major areas of the target surface is higher than a predetermined temperature.  
      Besides, in the temperature sensor  22 , the temperature profile of the target surface is detected by the image capturing module  20  using microwave sensing technology. In the temperature sensor  22 , the image processing module  30  filters the heat image  12  of the target surface according to the temperature profile, and labels the high-temperature area, wherein the images of the high-temperature area is retained and the rest of the images of the heat image  12  is discarded.  
      Referring to  FIG. 5 .  FIG. 5  is a flowchart of the temperature sensing method of the present invention. Taking the temperature sensor  22  in  FIG. 4  as an example, the temperature sensing method comprises the following steps: 
          S 60 : measuring the temperature profile of the target surface and capturing a heat image  12  of the target surface,     S 62 : filtering the heat image  12  of the target surface according to the temperature profile and labeling the high-temperature area,     S 64 : comparing the image of the high-temperature area with the image of the major area  42  stored in a image database  40  and deciding whether the high-temperature area is the major area  16 .        

      The step of S 62  further comprises the step of labeling only the parts of the heat image  12  with the temperature exceeding the predetermined temperature.  
      The step of S 62  also comprises a step of displaying the images of the high-temperature areas on the display module  54 .  
      After the step S 64  is completed, the step of S 66  to send out an alarm may be added to inform a trained person that the high-temperature area of the target surface is the major area  16 .  
      Therefore, the temperature sensor of the present invention not only automatically judges whether the temperature of the high-temperature area of the target surface is higher than a predetermined temperature but also automatically sends out an alarm signaling that the high-temperature area is the major area, not requiring a trained person to make the judgment. Thus the temperature sensor of the present invention has a greater efficiency than that of the prior art and reduces the costs of labor. Furthermore, the temperature sensing method judges by comparing the temperatures of certain areas of concern, so as to prevent erroneous judgment that may be caused by factors like environment, clothing types, and all kinds of personal accessories.  
      With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.