JP2004310397A - Device for determining wearing of mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine whether or not a person is wearing a mask according to an image of the person's face. <P>SOLUTION: It is determined whether or not the subject of photography is wearing a mask as the centerline between the top (head) and the bottom (jaw) of the person's face photographed with a camera serves as a vertical center and image information derived from a predetermined area above the vertical center is compared with that derived from a predetermined area below the vertical center. When the person is wearing a mask, the mask part and the skin part differ in brightness, color, and the amount of edges where brightness varies, so these are preferably used as image information. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for processing an image of a person's face for personal authentication and detection of a person's state, and to a mask wearing determination apparatus that determines whether or not a person is wearing a mask.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a device for detecting the position and posture of a human head, there has been disclosed a measurement device for photographing a subject with two cameras, extracting and tracking feature points, and determining their three-dimensional positions (Patent) Reference 1).
[0003]
Patent Document 2 discloses an authentication device that detects the direction of a target user's face, performs face recognition according to the direction of the face, and performs personal authentication. Here, a user is photographed from various angles in advance to create a collation image database, and personal authentication is performed by comparing the database with the database.
[0004]
[Patent Document 1]
JP-A-11-63927 (Claims)
[0005]
[Patent Document 2]
JP-A-2002-288670 (Claims)
[0006]
[Problems to be solved by the invention]
However, since the conventional technology is processed on the assumption that all human faces are visible, accurate authentication and detection cannot be performed when a human is wearing a mask.
[0007]
An object of the present invention is to easily and accurately determine whether or not a person is wearing a mask from a captured image. When it is possible to determine that a person is wearing a mask, a device that processes an image of a person's face for personal authentication and state detection of a person can perform image processing on the premise of wearing a mask. It is possible to improve detection accuracy. Further, since the wearing of a mask is an explicit manifestation of having a cold for a driver of a car, the detection of the wearing of the mask allows the driver of the car to consider the physical condition of the driver. Control becomes possible.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is directed to an imaging unit that captures a human face to obtain a captured image, a vertical center detection unit that detects a vertical center of a human face in the captured image, A mask wear determination unit that determines whether or not a person is wearing a mask by comparing image information of a predetermined area in an upper part and a lower part of a mask.
[0009]
Further, in the present invention, when comparing the image information of the predetermined area in the upper part and the lower part in the upper and lower centers, the mask wearing determination unit may include at least one of the luminance, the color, and the amount of the edge part in the captured image. It is preferred to use one.
[0010]
[Action]
According to the present invention, it is possible to determine whether or not a person is wearing a mask by comparing image information of a predetermined area in an upper part and a lower part of a human face with respect to a human face. By using this determination, it is possible to perform image processing on the assumption that a person is wearing a mask, and it is possible to perform individual authentication and state detection of a person with high accuracy.
[0011]
Further, when comparing the image information of the upper part and the lower part of the human face, at least one of the brightness, the color, and the amount of the edge portion of the captured image is used as the image information. The presence or absence of wearing a mask can be determined.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
[0013]
Hereinafter, embodiments of the present invention will be described. FIG. 1 is a diagram showing a processing flow of the mask wearing determination device of the present invention. The imaging unit 110 acquires a captured image including a human face. Here, a CCD camera, a CMOS camera, or the like can be used. Next, the vertical center detecting unit 120 detects the vertical center of the face in the captured image. The vertical center is the vertical center position of the face in the captured image, and specifically, the horizontal line 212 shown in FIG. 2 is the vertical center. In FIG. 2, there is no mask in the upper half of the face 220 and the mask 250 can be seen in the lower half. In the detection of the vertical center, the contour of the face is detected from the differential value of the luminance of the image, the uppermost portion 211 and the lowermost portion 213 are specified, and the center of these two lines (211, 213) is set to the vertical center 212. It is possible to
[0014]
However, the vertical center does not necessarily need to be at the center between the uppermost part 211 and the lowermost part 213 of the face, and the mask being worn is located substantially below the vertical center, and the face without the mask is approximately above the vertical center. Can be set arbitrarily within a range that can be detected.
[0015]
When the vertical center is detected, the mask wearing determination unit 130 determines whether the mask is worn. At this time, the presence or absence of the mask is determined by comparing the image information of the predetermined area 230 above the vertical center 212 and the predetermined area 240 below the same. In the face of the person wearing the mask, the brightness, color, and edge amount are different between the predetermined area 230 above the vertical center 212 and the predetermined area 240 below the center. By doing so, it is possible to determine whether or not a mask is worn.
[0016]
When the upper predetermined region 230 and the lower predetermined region 240 are compared by such means, when a person wears a mask, the brightness of the lower predetermined region 240 becomes higher. Similarly, when the mask is worn, the color of the lower predetermined region 240 shows a color closer to white. Generally, the mask is for white. Therefore, the luminance processing unit 131 and the color processing unit 132 can compare the two predetermined areas 230 and 240 to determine whether or not a person is wearing a mask.
[0017]
Further, the luminance of the image is differentiated in the upper predetermined region 230 and the lower predetermined region 240, and an edge portion where the luminance value changes can be detected. When the mask is worn, the edge portion is hardly detected in the lower predetermined region 240. This is because the mask has no edge portion. On the other hand, in the upper predetermined region 230, a large number of edge portions caused by eyes, eyebrows, and the like are detected. Therefore, by comparing the amounts of the edge portions included in the two predetermined regions 230 and 240, it can be determined whether or not a person is wearing a mask. This processing is performed by the edge processing unit 133.
[0018]
In FIG. 1, the mask wearing determination unit 130 includes a luminance processing unit 131, a color processing unit 132, and an edge processing unit 133, but at least one of them may be used in practice. Further, it is also possible to further improve the accuracy by using a plurality.
[0019]
The presence / absence of wearing a mask is determined by the means described above, and the result of the determination is finally output (140). This determination is indispensable for personal authentication and human state detection, and the accuracy of personal authentication is improved by clarifying whether or not a mask is worn, and the human state can also be accurately detected. It can also be used for driving control support of automobiles.
[0020]
Hereinafter, the determination process of wearing a mask using luminance will be described in more detail. FIG. 3 is a diagram showing a flow of this processing. First, a captured image captured by the imaging unit 110 is captured (301). Next, the vertical center 212 of the face of the captured image is detected (302), and predetermined regions 230 and 240 at the upper and lower portions of the vertical center are cut out (303). Then, the average value of the luminance in these predetermined areas is calculated (304), and the two are compared (305). In this comparison, the average luminance value in the predetermined area 230 above the vertical center 212 is subtracted from the average luminance value in the predetermined area 240 below the vertical center 212. If the difference is larger than the predetermined value, it is determined that the mask is worn. (306), it is determined that the mask is not worn when the brightness is small (that is, almost the same brightness) (307).
[0021]
Here, the positions of the upper and lower predetermined regions 230 and 240 for calculating the average luminance value may be set so that a portion where the mask is not worn and a portion where the mask is worn can be accurately processed. However, at least both are set at positions sandwiching the vertical center 212. In other words, the vertical center 212 should be set at a position that divides the lower part with the mask and the upper part without the mask. Actually, the center between the uppermost part 211 and the lowermost part 213 of the face is appropriate.
[0022]
Further, the predetermined value in the determination unit 305 for determining whether to wear the mask can be arbitrarily set based on the difference in luminance caused by the difference between the human face and the mask.
[0023]
Similarly to the above description, it is possible to determine whether or not a mask is worn by detecting a difference in color and a difference in the amount of an edge portion in a predetermined region between an upper portion and a lower portion.
【The invention's effect】
According to the present invention, it is possible to determine whether or not the subject is wearing a mask using only the captured image. Since this does not require complicated processing, it is possible to easily determine whether or not to wear a mask even when the processing capacity is limited, such as in an automobile or a portable terminal. By using this determination result, it becomes possible to perform image processing on the premise of wearing a mask, improve the accuracy of personal authentication, and accurately detect the state of a person. It is possible to do.
[Brief description of the drawings]
FIG. 1 is a diagram showing a processing flow of a mask wearing determination device of the present invention.
FIG. 2 is a diagram illustrating an example of processing of a captured image.
FIG. 3 is a diagram showing a flow of mask wearing determination using luminance.
[Explanation of symbols]
110 Imaging means 120 Vertical center detecting section 130 Mask wearing determining section 131 Luminance processing section 132 Color processing section 133 Edge processing section 211 Top section 212 of face Top and bottom center 213 Lower section 230 of face Upper section where image information is compared And the predetermined area 250 at the bottom of the mask

Claims (2)

Imaging means for capturing a human face to obtain a captured image;
In the captured image, a vertical center detecting unit that detects the vertical center of a human face,
A mask wear determination device, comprising: a mask wear determination unit that determines whether or not a person is wearing a mask by comparing image information of a predetermined region in an upper portion and a lower portion of the upper and lower centers. The mask wearing determination unit, when comparing the image information of the predetermined area in the upper and lower portions of the upper and lower center, using at least one of the brightness, color, the amount of the edge portion in the captured image The mask wear determination device according to claim 1, wherein:

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