JP2010134490A - Detection device and method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more accurately detect an opened/closed state of an eye. <P>SOLUTION: A face direction detection part 121 detects a direction of a face of a person based on a face image that is an image of the face of the person photographed by a camera 111. An eye detection part 122 detects size of an eye of the person based on the face image. An opening/closing degree calculation part 123 calculates an opening/closing degree wherein an opening/closing degree showing opening condition of the eye of the person based on the size of the eye of the person in the face image is corrected to a value when seeing the face of the person from the front based on the detected direction of the face of the person. The detection device can be applied to an onboard device detecting an opened/closed state of an eye of a driver. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a detection apparatus and method, and a program, and more particularly, to a detection apparatus and method for detecting an open / closed state of a human eye, and a program.

  Conventionally, the driver's face is photographed, and the degree of opening / closing indicating the degree of opening of the driver's eyes is detected based on the vertical width (height) of the driver's eyes in the photographed image, and based on the detected degree of opening / closing. Thus, it has been proposed to detect a driver's sleep.

  By the way, when a human face is photographed with a camera, the vertical width of the human eye in the obtained image varies depending on the orientation of the face even if the vertical width of the eye does not actually change. For example, when the face is facing up or down, the vertical width of the eyes in the captured image is narrower than when the face is facing the front of the camera. Therefore, when the degree of opening / closing of the eyes is detected based on only the vertical width of the driver's eyes in the captured image, the degree of opening / closing is detected small even though the eyes are open depending on the direction of the driver's face. There are times when

  Therefore, conventionally, based on the ratio of the distance between the eyes and nose when the driver's face is at the reference position and the distance between the eyes and nose, the measured value of the vertical length of the eyes is changed to the value at the reference position. It has been proposed to correct (see, for example, Patent Document 1). For example, it is possible to improve the reliability of the degree of opening / closing by detecting the degree of opening / closing of the eyes using the invention described in Patent Document 1.

Japanese Patent No. 3296118

  However, in the invention described in Patent Document 1, it is necessary to detect the position of the nose other than the eyes. For example, when the driver's nose cannot be detected, such as when wearing a mask, the vertical width of the eyes is reduced. As a result, the degree of opening and closing of the eyes cannot be accurately detected.

  The present invention has been made in view of such a situation, and makes it possible to detect the open / closed state of the eyes more accurately.

  A detection apparatus according to one aspect of the present invention includes a face direction detection unit that detects the direction of a person's face based on an image obtained by photographing a person's face, and an eye detection unit that detects the size of a human eye in the image. The degree of opening / closing that indicates the degree of opening of the person's eyes based on the size of the person's eyes in the image is corrected to the value when the person's face is viewed from the front based on the detected orientation of the person's face And an opening / closing degree calculation means for calculating.

  In the detection device according to one aspect of the present invention, the orientation of the human face is detected based on the image obtained by photographing the human face, the size of the human eye in the image is detected, and the size of the human eye in the image is detected. An opening / closing degree is calculated by correcting the opening / closing degree indicating the degree of opening of the person's eyes based on the height to a value when the person's face is viewed from the front based on the detected face direction of the person.

  Therefore, the open / closed state of the eyes can be detected more accurately.

  The face orientation detection means, the eye detection means, and the open / close degree calculation means are configured by, for example, a CPU (Central Processing Unit) or an ECU (Electronic Control Unit).

  The eye detection means detects the vertical and horizontal widths of the human eyes in the image, and the open / close degree calculation means determines the ratio between the vertical and horizontal widths of the human eyes in the image. Based on the above, it is possible to calculate the open / closed degree corrected to the value when the human face is viewed from the front.

  Thereby, the open / closed state of the eyes can be accurately detected regardless of the size and orientation of the face of the person in the image.

  In this detection device, threshold value setting means for acquiring a predetermined amount of data on the degree of opening / closing when a person has eyes open, and setting a threshold value for determining whether or not the person has eyes open based on the data; Further, it is possible to further provide determination means for determining whether or not a person has opened his eyes by comparing the degree of opening and closing with a threshold value.

  This makes it possible to accurately determine whether or not a person has his eyes open.

  The threshold setting unit and the determination unit are configured by, for example, a CPU (Central Processing Unit) or an ECU (Electronic Control Unit).

  If the frequency at which the detected degree of opening / closing exceeds the threshold exceeds a predetermined value, the threshold setting means can correct the threshold based on the degree of opening / closing within a predetermined period.

  Accordingly, it is possible to accurately determine whether or not a person has his eyes open in a flexible manner in response to a change in the state of the eyes and a change in the person to be detected.

  Threshold value setting means for acquiring a predetermined amount of data on the degree of opening / closing when a person has eyes closed, and setting a threshold value for determining whether or not the person has eyes closed based on the data; By the comparison, it is possible to further provide a determination unit that determines whether or not a person has closed eyes.

  Thereby, it is possible to accurately determine whether or not a person has closed eyes.

  The threshold setting unit and the determination unit are configured by, for example, a CPU (Central Processing Unit) or an ECU (Electronic Control Unit).

  The threshold value setting means can correct the threshold value based on the degree of opening / closing within a predetermined period when the frequency at which the detected degree of opening / closing falls below the threshold exceeds a predetermined value.

  Thus, it is possible to accurately determine whether or not a person is closing his / her eyes, flexibly responding to changes in the state of the eyes and changes in the person to be detected.

  According to the detection method of one aspect of the present invention, the detection device detects the orientation of the person's face based on the image obtained by photographing the person's face, detects the size of the person's eyes in the image, and A step of calculating an opening / closing degree in which the opening / closing degree indicating the degree of opening of the person's eyes based on the size of the eyes is corrected to a value when the face of the person is viewed from the front based on the orientation of the detected person's face; Including.

  A program according to one aspect of the present invention detects, on a computer, the orientation of a person's face based on an image obtained by photographing the person's face, detects the size of the person's eyes in the image, and A process including a step of calculating an opening / closing degree in which the opening / closing degree indicating the degree of opening of the person's eyes based on the size is corrected to a value when the person's face is viewed from the front based on the detected face direction of the person Execute

  In the detection method or program according to one aspect of the present invention, the orientation of a person's face is detected based on an image of a person's face, the size of a person's eyes in the image is detected, and the person's face in the image is detected. The degree of opening / closing is calculated by correcting the degree of opening / closing indicating the degree of opening of the person's eyes based on the size of the eyes to a value when the person's face is viewed from the front based on the detected orientation of the person's face.

  Therefore, the open / closed state of the eyes can be detected more accurately.

  As described above, according to one aspect of the present invention, the open / closed state of the eyes can be detected. In particular, according to one aspect of the present invention, the open / closed state of the eyes can be detected more accurately.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram showing a first embodiment of an eye open / close detection system to which the present invention is applied. The eye opening / closing detection system 101 in FIG. 1 captures the face of the subject to be detected, and detects the degree of opening / closing indicating the degree of eye opening of the subject based on the photographed image. Hereinafter, a case where the eye opening / closing detection system 1 is installed in a vehicle and the degree of opening / closing of the driver's eyes is detected will be described.

  The eye opening / closing detection system 101 is configured to include a camera 111 and a detection device 112.

  The camera 111 shoots the face of the driver whose eye opening degree is to be detected, and images (hereinafter referred to as face images) obtained as a result of the shooting are detected by the face orientation detection unit 121 and the eye detection unit of the detection device 112. 122. For example, the camera 111 is installed on the steering column, takes a picture of the driver almost from the front, is installed near the center of the center mirror (room mirror) (around the center mirror is attached to the car), and obliquely forward Take a picture of the driver from above.

  The detection device 112 is configured to include a face orientation detection unit 121, an eye detection unit 122, and an opening / closing degree calculation unit 123.

  The face orientation detection unit 121 detects the face orientation of the driver based on the face image by a predetermined method. The face orientation detection unit 121 supplies information indicating the detection result to the opening / closing degree calculation unit 123.

  The eye detection unit 122 detects the size of the driver's eyes in the face image by a predetermined method. The eye detection unit 122 supplies information indicating the detection result to the open / close degree calculation unit 123.

  As described later with reference to FIGS. 2 to 5, the opening / closing degree calculation unit 123 opens and closes the driver's eyes based on the orientation of the driver's face and the size of the driver's eyes in the face image. Detect the degree. The opening / closing degree calculation unit 123 supplies information indicating the detection result to a subsequent apparatus.

  Next, the eye opening / closing degree detection processing executed by the eye opening / closing detection system 101 will be described with reference to the flowchart of FIG. This process is started when the engine of the vehicle provided with the eye opening / closing detection system 101 is started, and is ended when the engine is stopped, for example.

  In step S1, the eye opening / closing detection system 101 acquires a face image. Specifically, the camera 111 captures the driver's face. The camera 111 supplies the face image obtained as a result of shooting to the face direction detection unit 121 and the eye detection unit 122.

  In step S2, the face orientation detection unit 121 detects the face orientation. That is, the face direction detection unit 121 detects the face direction of the driver based on the face image by a predetermined method. The driver's face orientation is, for example, parallel to the optical axis of the camera 111 and with the direction toward the camera 111 as a reference direction, the angle α in the vertical direction with respect to the reference direction of the driver's face and the left-right direction Is represented by the angle β. The face orientation detection unit 121 supplies information indicating the detected driver's face orientation to the opening / closing degree calculation unit 123.

  Note that the method by which the face direction detection unit 121 detects the face direction is not limited to a specific method, and it is desirable to apply a method that can detect the face direction more easily, quickly, and accurately.

  In step S3, the eye detection unit 122 detects the vertical width and horizontal width of the eyes. Specifically, the eye detection unit 122 detects the position of the driver's eyes in the face image by a predetermined method, and further detects the detected vertical and horizontal widths of the eyes (both units are pixels). The eye detection unit 122 supplies information indicating the detected width and vertical width of the driver's eyes to the opening / closing degree calculation unit 123.

  Note that the method of detecting the vertical and horizontal widths of the eyes by the eye detection unit 122 is not limited to a specific method, and a method that can detect the vertical and horizontal widths of the eyes more easily, quickly, and accurately is applied. It is desirable.

  In step S4, the opening / closing degree calculation unit 123 calculates the opening / closing degree of the eyes. Here, a method for calculating the degree of opening and closing the eyes will be described with reference to FIGS.

  The human eye changes the vertical width (height) of the eye by opening and closing, but the horizontal width hardly changes. Therefore, the eye opening / closing detection system 101 uses the vertical width of the eye / the horizontal width of the eye as the degree of opening and closing. As described above, by using the ratio of the vertical width to the horizontal width of the eyes as the degree of opening and closing, a change in the size of the driver's eyes in the face image caused by a change in the distance between the camera 111 and the driver's face, etc. It is prevented that the detection result of the opening / closing degree is affected.

  By the way, the vertical width and the horizontal width of the driver's eyes viewed from the camera 111 change depending on the direction of the driver's face with respect to the camera 111 even if the actual vertical and horizontal widths of the eyes do not change.

  3 and 4 show models of the driver's face orientation and eye position. Specifically, FIG. 3 shows a model when the face of the driver 151 is facing the camera 111 in a direction parallel to the optical axis of the camera 111, that is, facing the front of the camera 111. 4 shows a model when the face of the driver 151 is directed upward by an angle α from the state of FIG. 3. In the figure, the axis A represents an axis parallel to the optical axis of the camera 111, and the line E represents the position of the driver 151 in the eye height direction. Hereinafter, it is assumed that the actual eye vertical width of the driver 151 is Ha.

  As shown in FIG. 3, when the face of the driver 151 is facing the front of the camera 111, the vertical width Hc1 of the eye of the driver 151 viewed from the camera 111 is almost equal to the vertical width Ha of the actual eye. Will be equal. The vertical width of the eyes of the driver 151 in the face image is a size corresponding to the vertical width Hc1.

  On the other hand, as shown in FIG. 4, when the face of the driver 151 faces upward with respect to the axis A by an angle α, the vertical width Hc2 of the eye of the driver 151 viewed from the camera 111 is It becomes smaller than the vertical width Ha of the eyes. Specifically, FIG. 5 is an enlarged view of the triangle indicated by the oblique lines in FIG. 4, and it can be seen from this figure that Hc2≈Ha × cosα. The vertical width of the eyes of the driver 151 in the face image is a size corresponding to the vertical width Hc2. The same applies to the case where the face of the driver 151 faces downward with respect to the axis A by an angle α.

  Although detailed description is omitted, similarly, when the driver's face is directed right or left by an angle β from the direction parallel to the optical axis of the camera 111 with respect to the camera 111, the actual driver When the lateral width of the eyes is Wa, the lateral width Wc of the driver's eyes viewed from the camera 111 is approximately equal to Wa × cos β.

  Accordingly, when the driver's face is oriented in the direction of angle α in the vertical direction and angle β in the horizontal direction with respect to the reference direction (parallel to the optical axis of the camera 111 and toward the camera 111). When the vertical width of the driver's eyes in the face image is Hp and the horizontal width is Wp, the opening / closing degree of the driver's eyes, which represents the ratio of the actual driver's eyes' vertical width to the horizontal width, is expressed by the following equation (1). ).

  That is, the degree of opening and closing of the expression (1) is the ratio of the vertical and horizontal width of the driver's eyes in the face image when the driver is facing the front of the camera 111 based on the direction of the driver's face. The value corrected to the value, in other words, the value corrected to the value when the driver's face is viewed from the front.

  The degree-of-opening / closing degree calculation unit 123 calculates the degree of opening / closing of the driver's eyes according to the equation (1), and outputs information indicating the calculated degree of opening / closing of the eyes to the subsequent apparatus.

  Thereafter, the process returns to step S1, and the processes after step S1 are executed.

  In this way, regardless of the direction of the driver's face, the degree of opening / closing of the driver's eyes can be accurately detected without using a face portion other than the driver's eyes.

  Note that if the driver's face orientation with respect to the reference direction is greater than or equal to a predetermined angle, there is a high possibility that the eyes are not sufficiently reflected in the face image, and the reliability of the opening / closing degree is lowered. The degree of opening / closing may not be detected.

  Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the second embodiment of the present invention makes it possible to determine the opening / closing of the eyes of the driver based on the degree of opening / closing of the eyes.

  FIG. 6 is a block diagram showing a second embodiment of an eye opening / closing detection system to which the present invention is applied. 6 is configured to include a camera 111, a detection device 112, and a determination device 211. That is, the eye opening / closing detection system 201 is configured by adding a determination device 211 to the eye opening / closing detection system 101 of FIG. In the figure, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description of parts having the same processing will be omitted because it will be repeated.

  The determination device 211 is configured to include a threshold setting unit 221, an accumulation unit 222, and a determination unit 223.

  The threshold setting unit 221 acquires information indicating the degree of opening / closing of the driver's eyes from the degree-of-opening / closing degree calculation unit 123, and actually captures a face image that is a detection target of the degree of opening / closing of the eyes. Data indicating whether the person has opened or closed his eyes is acquired from the outside. The threshold setting unit 221 associates the detected degree of opening / closing of the driver's eyes with the result of opening / closing the eyes of the driver inputted from the outside, and accumulates them in the accumulating unit 222.

  Then, the threshold setting unit 221 determines whether or not the driver is opening his eyes based on the data of the degree of opening and closing when the driver is opening his eyes among the data stored in the storage unit 222. Set the threshold THopen to do. Further, the threshold setting unit 221 determines whether or not the driver is closing his eyes based on the data of the degree of opening and closing when the driver is closing his eyes among the data stored in the storage unit 222. Set the threshold THclose to do. The threshold setting unit 221 supplies information indicating the set threshold THopen and threshold THclose to the determination unit 223.

  Further, after setting the threshold value THopen and the threshold value THclose, the threshold value setting unit 221 compares the detected degree of opening / closing of the driver's eyes with the threshold value THopen and the threshold value THclose, and corrects the threshold value THopen and the threshold value THclose as appropriate. The threshold setting unit 221 supplies information indicating the corrected threshold THopen and threshold THclose to the determination unit 223.

  The storage unit 222 is configured by a recording medium such as an HDD (hard disk drive).

  The determination unit 223 acquires information indicating the degree of opening / closing of the driver's eyes from the opening / closing degree calculation unit 123. The determination unit 223 compares the acquired degree of opening / closing of the driver's eyes with the threshold set by the threshold setting unit 221 so that the driver determines opening / closing of the eyes. The determination unit 223 outputs information indicating the determination result to a subsequent apparatus.

  Next, the learning process executed by the eye opening / closing detection system 201 will be described with reference to the flowchart of FIG. This process is started when, for example, an instruction to start a learning process is input to the eye opening / closing detection system 101 via an input unit (not shown).

  The processing in steps S101 to S104 is the same as the processing in steps S1 to S4 in FIG. 2, and the description thereof will be omitted because it will be repeated. By this process, the degree of opening / closing of the driver's eyes is detected based on the driver's face image, and information indicating the degree of opening / closing of the detected eyes is supplied from the opening / closing degree calculation unit 123 to the threshold setting unit 221. Is done.

  In step S105, the threshold setting unit 221 acquires the result of opening and closing the eyes. Specifically, data indicating whether the driver or other user actually opened or closed the driver's eyes when taking a face image that was the target of detection of the opening / closing degree this time. Is input to the threshold setting unit 221 via an input unit (not shown), and the threshold setting unit 221 acquires the input data.

  In step S106, the threshold setting unit 221 accumulates data. Specifically, the threshold setting unit 221 associates the degree of opening / closing of the driver's eyes detected this time with the result of opening / closing of the eyes of the driver input from the outside, and accumulates them in the accumulation unit 222.

  In step S <b> 107, the threshold setting unit 221 determines whether a predetermined amount of data is stored in the storage unit 222. If it is determined that the predetermined amount of data has not yet been accumulated, the process returns to step S101.

  Thereafter, the processes in steps S101 to S107 are repeatedly executed until it is determined in step S107 that a predetermined amount of data has been accumulated. During this time, the driver stores, for example, data of detection results of various face orientations and open / closed degrees in the open / closed state of the eyes while changing the orientation of the face, opening and closing eyes. To accumulate.

  On the other hand, if it is determined in step S107 that a predetermined amount of data has been accumulated, that is, if it is determined that sufficient data has been accumulated to set a threshold value for determining eye opening / closing, the process proceeds to step S107. The process proceeds to S108.

  In step S108, the threshold setting unit 221 sets a threshold for determining opening / closing of the eyes. For example, the threshold setting unit 221 calculates an average value of the degree of opening and closing when the driver's eyes are open based on the data stored in the storage unit 222, and sets the calculated average value as the threshold THopen. . Further, the threshold setting unit 221 calculates an average value of the degree of opening and closing when the driver's eyes are closed based on the data stored in the storage unit 222, and sets the calculated average value as the threshold value THclose. . The threshold setting unit 221 supplies information indicating the calculated threshold THopen and threshold THclose to the determination unit 223. Thereafter, the learning process ends.

  Next, the eye opening / closing determination process executed by the eye opening / closing detection system 201 will be described with reference to the flowchart of FIG. This process is started, for example, when the engine of the vehicle provided with the eye opening / closing detection system 201 is started, and is ended when the engine is stopped.

  The processing in steps S131 through S134 is the same as the processing in steps S1 through S4 in FIG. 2, and the description thereof will be omitted because it will be repeated. In this process, the degree of opening / closing of the driver's eyes is detected based on the driver's face image, and information indicating the degree of opening / closing of the detected eyes is sent from the opening / closing degree calculation unit 123 to the threshold setting unit 221 and the determination. To the unit 223.

  In step S135, the determination unit 223 determines opening / closing of the eyes. Specifically, the determination unit 223 determines that the driver has opened his eyes when the detected degree of opening / closing of the driver's eyes is above the threshold THopen, and when the driver's eyes open / closed is below the threshold THclose, It is determined that the driver is closing his eyes, and if the value is between the threshold THopen and the threshold THclose, it is determined that the driver's eyes are half open. The determination unit 223 outputs information indicating the determination result to a subsequent apparatus.

  In step S136, the threshold setting unit 221 accumulates the degree of opening / closing. That is, the threshold setting unit 221 stores data indicating the degree of opening / closing of the eyes of the driver detected by the detection device 112 in the storage unit 222 together with the detected time.

  In step S137, the threshold setting unit 221 determines whether the frequency at which the degree of opening / closing of the eyes exceeds the threshold THopen exceeds a predetermined value. Specifically, the threshold setting unit 221 determines whether the driver's eye open / closed degree detected within the latest predetermined time (for example, the past 3 minutes) based on the data stored in the storage unit 222 is: Check how often the threshold THopen is exceeded. If the threshold setting unit 221 determines that the frequency exceeds a predetermined value (for example, 80%), the process proceeds to step S138.

  In step S138, the threshold setting unit 221 corrects the threshold THopen. That is, for example, when the driver changes, or the driver or the surrounding state changes (for example, the driver's surroundings change from a dazzling state to a dark state), the degree of opening and closing of the eyes is the threshold THopen When the value frequently exceeds the threshold value, the threshold value setting unit 221 corrects the threshold value THopen.

  For example, the threshold setting unit 221 creates a histogram of eye open / closed degrees detected within the latest predetermined time (for example, the past 3 minutes). Then, the threshold value setting unit 221 calculates an average value of the opening / closing degree in the data within a predetermined range centered on the peak of the created histogram as a new threshold value THopen. At this time, by limiting the data used for calculation of the threshold THopen to a predetermined range centered on the peak of the histogram, the average degree of opening / closing detected when the driver closes his eyes due to blinking etc. It can be excluded from the calculation target of the value. The threshold setting unit 221 supplies information indicating the calculated threshold THopen to the determination unit 223. Thereafter, the process returns to step S131, and the processes after step S131 are executed.

  Here, a specific example of the processing of steps S137 and S138 will be described with reference to FIG. FIG. 9 shows an example of the detection result of the degree of opening and closing of the driver's eyes, and the horizontal axis shows time. Further, Dmax indicates the maximum value of the degree of opening / closing of the driver's eyes detected during the learning process of FIG. 7, and Dmin indicates the minimum value.

  For example, if the driver's eyes are changed during the period P1, and the driver's eyes are longer than the driver's eyes, the driver's eyes are longer than the driver's eyes before the change, as shown in FIG. After switching, the frequency with which the degree of opening / closing of the detected eyes exceeds the threshold THopen increases. If the frequency at which the degree of opening / closing of the eyes exceeds the threshold value THopen in the period P2 having a predetermined length exceeds the predetermined value, in step S138, for example, based on the degree of opening / closing of the eyes detected in the period P2. The threshold THopen is corrected.

  For example, when the surrounding area is dazzling and the driver continues to squint, and the threshold value THopen is corrected to a small value in step S141, which will be described later, the surrounding area becomes dark and the driver's eyes are original. Similarly, when the driver returns from the narrowed state to the original state, such as when returning to the size, the detected frequency of eye opening / closing exceeds the threshold THopen, and as a result, the threshold THopen Is corrected.

  For example, if the degree of opening / closing of the eyes exceeds the maximum value Dmax or the average value of the degree of opening / closing of the eyes continues to exceed the threshold THopen, the driver is likely to change, and the threshold THopen It is desirable to correct. Therefore, whether or not the degree of opening / closing of the eyes exceeds the maximum value Dmax and whether or not the state where the average value of the degree of opening / closing of the eyes exceeds the threshold value THopen continues for a predetermined time is used as the determination condition in step S137. Also good.

  On the other hand, if it is determined in step S137 that the frequency at which the eye open / close degree exceeds the threshold value THopen does not exceed the predetermined value, the process proceeds to step S139.

  In step S139, the threshold setting unit 221 determines whether or not the frequency at which the degree of opening / closing of the eyes falls below the threshold THclose exceeds a predetermined value. The frequency that the threshold setting unit 221 has the degree of opening / closing of the driver's eyes below the threshold THclose within the most recent predetermined time (for example, the past 3 minutes) exceeds a predetermined value (for example, 80%). If it is determined, the process proceeds to step S140.

  In step S140, the threshold setting unit 221 corrects the threshold THclose. That is, for example, when the driver changes and the degree of eye opening and closing frequently falls below the threshold THclose, the threshold setting unit 221 corrects the threshold THclose.

  For example, the threshold setting unit 221 creates a histogram of eye open / closed degrees detected within the latest predetermined time (for example, the past 3 minutes). The threshold setting unit 221 calculates the average value of the open / closed degree in the data within a predetermined range centered on the peak of the created histogram as the new threshold THclose. At this time, by limiting the data used for calculating the threshold THclose to a predetermined range centered on the peak of the histogram, the degree of opening / closing detected when the driver is opening his eyes is calculated as an average value. Can be excluded from the subject. The threshold setting unit 221 supplies information indicating the calculated threshold THclose to the determination unit 223. Thereafter, the process returns to step S131, and the processes after step S131 are executed.

  Here, with reference to FIG. 10, the specific example of the process of step S139 and S140 is demonstrated. FIG. 10 shows an example of the detection result of the degree of opening and closing of the driver's eyes, similar to FIG.

  For example, during the period P11, the driver is changed, and in the period P12 after the change, when the driver closes his eyes due to dozing, depending on the shape of the driver's eyes, as shown in FIG. There is a case where the frequency of the degree of opening / closing of the detected eye is lower than the threshold value THclose. Then, when the frequency that the degree of opening / closing of the detected eyes falls below the threshold THclose in the predetermined length of period P12 exceeds the predetermined value, in step S140, for example, the degree of opening / closing of the eyes detected in period P12 Based on the above, the threshold THclose is corrected.

  Note that, for example, when the degree of opening / closing of the eyes is below the minimum value Dmin, or when the average value of the degree of opening / closing of the eyes continues below the threshold THclose, the driver is highly likely to change, and the threshold THclose It is desirable to correct. Therefore, whether or not the degree of opening / closing of the eyes is below the minimum value Dmin, and whether or not the state where the average value of the degree of opening / closing of the eyes is below the threshold THclose continues for a predetermined time are used as the determination conditions in step S139. Also good.

  On the other hand, if it is determined in step S139 that the frequency at which the degree of opening / closing of the eyes falls below the threshold value THclose does not exceed the predetermined value, the process proceeds to step S141.

  In step S141, the threshold setting unit 221 determines whether or not the frequency at which the degree of opening / closing of the eyes is between the threshold THopen and the threshold THclose exceeds a predetermined value. The threshold setting unit 221 determines that the frequency at which the degree of opening / closing of the driver's eyes is between the threshold THopen and the threshold THclose within a predetermined period of time (for example, the past three minutes) is a predetermined value (for example, 80% ), The process proceeds to step S142.

  In step S142, the threshold setting unit 221 calculates an average value of the degree of opening / closing of the eyes within the latest predetermined period (for example, the past 3 minutes).

  In step S143, the threshold setting unit 221 determines whether or not the obtained average value of the degree of opening / closing of the eyes is equal to or greater than a predetermined threshold. This threshold value is set, for example, to the maximum value of the degree of opening and closing when the driver closes his eyes in the data accumulated in the learning process of FIG. Thereby, when the average value of the obtained opening / closing degree is equal to or greater than the threshold value, it can be estimated that the driver generally opened his eyes within the most recent predetermined period. If it is determined that the obtained average opening / closing degree of the eyes is equal to or greater than a predetermined threshold, the process proceeds to step S144.

  In step S144, the threshold value THopen is corrected in the same manner as in step S138. Thereafter, the process returns to step S131, and the processes after step S131 are executed.

  On the other hand, if it is determined in step S143 that the calculated average value of the degree of opening / closing of the eyes is less than a predetermined threshold, the process proceeds to step S145.

  In step S145, the threshold value THclose is corrected in the same manner as in step S140. Thereafter, the process returns to step S131, and the processes after step S131 are executed.

  Here, with reference to FIG. 11, a specific example of the processing of steps S141 to S145 will be described. In addition, FIG. 11 has shown an example of the detection result of the opening / closing degree of a driver | operator's eyes similarly to FIG. 9 and FIG.

  For example, when the direction of the vehicle changes at time T1, direct sunlight enters the vehicle, and the driver narrows his eyes, as shown in FIG. 11, the detected degree of opening / closing of the eyes is a threshold THopen. And the threshold THclose is increased. If the frequency at which the degree of opening / closing of the eyes is between the threshold THopen and the threshold THclose exceeds a predetermined value in the period P21 having a predetermined length, in step S144, for example, the eye detected in the period P21 The threshold THopen is corrected based on the degree of opening / closing.

  It should be noted that, for example, when the driver's eyes are switched and the driver's eyes have a vertical width smaller than the driver's eyes before the replacement, the detected eye open / closed degree is the threshold THopen. The frequency between the threshold THclose increases, and as a result, the threshold THopen is corrected.

  In addition, for example, when the driver is switched and the driver closes the eyes after the switching, the detected degree of opening / closing of the eyes may be higher than the threshold THclose depending on the shape of the driver's eyes. . If the frequency at which the eye open / closed degree is between the threshold value THopen and the threshold value THclose exceeds a predetermined value in a predetermined length period, the threshold value THclose is corrected in step S145.

  As described above, the opening / closing of the driver's eyes can be accurately determined. In addition, even when the driver changes or the driver's eyes change, it is possible to accurately determine whether the driver's eyes are opened or closed in a flexible manner.

  A learning process is performed for each driver, threshold THopen and threshold THclose for each driver are obtained in advance, and the driver is authenticated by various biometrics such as face authentication, or operation means such as buttons are used. For example, the threshold THopen and the threshold THclose may be selected for each driver by selecting data.

  Further, only one of the threshold value THopen and the threshold value THclose may be obtained according to the use, and only one of whether the eyes are open or whether the eyes are closed may be determined.

  Furthermore, in the above description, the example of detecting the degree of opening / closing of the driver's eyes and determining the opening / closing of the eyes has been shown, but the present invention detects the degree of opening / closing of the eyes of a person other than the driver, and It can be applied to the determination of eye opening and closing.

  Further, the opening / closing degree of the eyes is not limited to the above-described example, and a value other than the ratio between the vertical width and the horizontal width of the eyes may be used.

  The series of processes described above can be executed by hardware or can be executed by software. When a series of processing is executed by software, a program constituting the software is installed in the computer. Here, the computer includes, for example, a general-purpose personal computer capable of executing various functions by installing various programs by installing a computer incorporated in dedicated hardware.

  FIG. 12 is a block diagram illustrating a hardware configuration example of a computer that executes the above-described series of processing by a program.

  In a computer, a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, and a RAM (Random Access Memory) 503 are connected to each other by a bus 504.

  An input / output interface 505 is further connected to the bus 504. An input unit 506, an output unit 507, a storage unit 508, a communication unit 509, and a drive 510 are connected to the input / output interface 505.

  The input unit 506 includes a keyboard, a mouse, a microphone, and the like. The output unit 507 includes a display, a speaker, and the like. The storage unit 508 includes a hard disk, a nonvolatile memory, and the like. The communication unit 509 includes a network interface or the like. The drive 510 drives a removable medium 511 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

  In the computer configured as described above, the CPU 501 loads the program stored in the storage unit 508 to the RAM 503 via the input / output interface 505 and the bus 504 and executes the program, for example. Is performed.

  The program executed by the computer (CPU 501) can be provided by being recorded on a removable medium 511 as a package medium or the like, for example. The program can be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

  In the computer, the program can be installed in the storage unit 508 via the input / output interface 505 by attaching the removable medium 511 to the drive 510. Further, the program can be received by the communication unit 509 via a wired or wireless transmission medium and installed in the storage unit 508. In addition, the program can be installed in the ROM 502 or the storage unit 508 in advance.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  Further, in the present specification, the term “system” means an overall apparatus composed of a plurality of apparatuses and means.

  Furthermore, the embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

1 is a block diagram showing a first embodiment of an eye opening / closing detection system to which the present invention is applied. It is a flowchart for demonstrating the eye opening / closing degree detection process performed by an eye opening / closing detection system. It is a figure for demonstrating the calculation method of the opening degree of eyes. It is a figure for demonstrating the calculation method of the opening degree of eyes. It is a figure for demonstrating the calculation method of the opening degree of eyes. It is a block diagram which shows 2nd Embodiment of the eye opening / closing detection system to which this invention is applied. It is a flowchart for demonstrating the learning process performed by the eye opening / closing detection system. It is a flowchart for demonstrating the eye opening / closing determination process performed by the eye opening / closing detection system. It is a figure for demonstrating the specific example of the correction process of threshold value THopen. It is a figure for demonstrating the specific example of the correction process of threshold value THclose. It is a figure for demonstrating the specific example of the correction process of threshold value THopen and threshold value THclose. And FIG. 11 is a block diagram illustrating an example of a configuration of a computer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Eye opening / closing detection system 111 Camera 112 Detection apparatus 121 Face direction detection part 122 Eye detection part 123 Opening / closing degree calculation part 201 Eye opening / closing detection system 211 Determination apparatus 221 Threshold setting part 222 Storage part 223 Determination part

Claims (8)

Face orientation detection means for detecting the orientation of the person's face based on an image of the person's face;
Eye detection means for detecting the size of the human eye in the image;
The degree of opening / closing indicating the degree of opening of the person's eyes based on the size of the person's eyes in the image is a value when the person's face is viewed from the front based on the detected orientation of the person's face. An opening / closing degree calculating means for calculating the corrected opening / closing degree. The eye detection means detects the vertical and horizontal widths of the human eye in the image,
The opening / closing degree calculating means corrects the ratio of the vertical and horizontal widths of the human eye in the image to a value when the human face is viewed from the front based on the detected orientation of the human face. The detection device according to claim 1, wherein the opening / closing degree is calculated. Threshold value setting means for acquiring a predetermined amount of data of the degree of opening and closing when the person has eyes open, and setting a threshold value for determining whether or not the person has eyes open based on the data;
The detection device according to claim 1, further comprising: a determination unit that determines whether or not the person is opening an eye by comparing the degree of opening and closing with the threshold value. The threshold value setting unit corrects the threshold value based on the degree of opening / closing within a predetermined period when the frequency at which the detected degree of opening / closing exceeds the threshold value exceeds a predetermined value. Detection device. Threshold value setting means for acquiring a predetermined amount of data of the degree of opening and closing when the person has eyes closed, and setting a threshold value for determining whether or not the person has eyes closed based on the data;
The detection device according to claim 1, further comprising: a determination unit that determines whether or not the person is closing eyes by comparing the degree of opening and closing with the threshold value. The threshold value setting unit corrects the threshold value based on the degree of opening / closing within a predetermined period when the frequency at which the detected degree of opening / closing is less than the threshold value exceeds a predetermined value. Detection device. The detection device
Based on the image of the person's face, the direction of the person's face is detected,
Detecting the size of the human eye in the image;
The degree of opening / closing indicating the degree of opening of the person's eyes based on the size of the person's eyes in the image is a value when the person's face is viewed from the front based on the detected orientation of the person's face. A detection method including a step of calculating the corrected opening / closing degree. On the computer,
Based on the image of the person's face, the direction of the person's face is detected,
Detecting the size of the human eye in the image;
The degree of opening / closing indicating the degree of opening of the person's eyes based on the size of the person's eyes in the image is a value when the person's face is viewed from the front based on the detected orientation of the person's face. A program for executing a process including a step of calculating the corrected opening / closing degree.

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