JP2014203186A - Monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitoring system capable of preventing distrust and overconfidence of a user with respect to the monitoring system.SOLUTION: A monitoring system comprises: a camera 11 for acquiring a face image of a user; a face image recognition section 21 and a state detection section 22 for detecting a state of the user on the basis of the face image of the user acquired by the camera 11; a determination section 23 for determining an irradiation condition of sunlight on the face of the user; a reliability calculation section 24 for transmitting the reliability of the detected state of the user on the basis of the irradiation condition of sunlight determined by the determination section 23; a monitor 31; and a speaker 32. The higher the possibility of irradiation of sunlight on the face of the user is, the lower the reliability calculation section 24 calculates the reliability of the detected state of the user.

Description

  The present invention relates to a monitoring system that detects a user's state based on a face image obtained by photographing a user's face and monitors the user's doze or looking away.

  Detects the user's eye opening and face orientation from the user's face image, such as a driver, and alerts when the user is determined to fall asleep or look away based on the detected eye opening and face orientation Has been proposed.

  For example, Patent Document 1 irradiates a user's face with near-infrared light, photographs the user's face illuminated with the near-infrared light with a camera, and extracts edge information from the photographed face image. Then, eyebrows and upper and lower eyelids, which are facial feature points, are detected from the extracted edge information, and the opening degree of the eyes is detected based on the detected positions of the eyebrows and upper and lower eyelids. Furthermore, an alarm sound is output when it is detected that the user is drowsy based on the detected opening of the eyes.

JP 2009-219555 A

  In patent document 1, when the disturbance light hits the user's face and the accuracy of detecting the feature points from the face image deteriorates, it is detected that the user is drowsy even though the user is not drowsy, and an alarm sound may be output There is. In this case, the user may distrust the monitoring system and stop using the monitoring system. In addition, when the accuracy of detecting feature points from a face image is deteriorated due to ambient light, the user may overtrust the monitoring system even though the user's sleepiness may not be detected.

  In view of the above circumstances, it is a primary object of the present invention to provide a monitoring system capable of suppressing user distrust and overconfidence with respect to the monitoring system.

  In order to solve the above problem, the invention according to claim 1 is a monitoring system, wherein the user obtains a face image of the user, and the user based on the face image obtained by the image obtaining means. Based on the state detection means for detecting the state of the user, the determination means for determining the sunlight irradiation mode on the user's face, and the state detection means based on the sunlight irradiation mode determined by the determination means Transmitting means for transmitting the reliability of the detected state of the user.

  According to the first aspect of the present invention, the face image of the user is acquired, and the state of the user is detected based on the acquired face image of the user. However, when ambient light is shining on the user's face, noise may be mixed in the face image and the detection accuracy of the user's state may deteriorate.

  Therefore, the irradiation mode of sunlight on the user's face is determined, and the reliability of the detected state of the user is transmitted to the user based on the determined irradiation mode of sunlight. Therefore, the user can recognize whether or not the detected state of the user may be trusted by the reliability based on the sunlight irradiation mode, that is, the disturbance light mixing mode in the face image. Therefore, it is possible to suppress the user from being overconfident or distrustful with the monitoring system.

The block diagram which shows the structure of a monitoring system. The figure which shows a notification screen. The flowchart which shows the process sequence which notifies reliability.

  Hereinafter, the monitoring system according to the present embodiment will be described with reference to the drawings. The monitoring system according to the present embodiment is mounted on a vehicle, and is assumed to monitor a driver who is a user, falling asleep or looking away.

  First, the configuration of the monitoring system 10 will be described with reference to FIG. The monitoring system 10 includes a camera 11 (image acquisition means), an illumination device 12, a GPS 13, a solar radiation sensor 14 (sunlight measurement means), a driver monitor ECU 20, a monitor 31, a speaker 32, and an external storage device 33 (storage means).

  The illuminating device 12 is an illuminating device such as a near infrared LED that irradiates near infrared light toward the face of the driver. The camera 11 is a CCD camera, for example, and has high sensitivity characteristics in the near infrared region. By using the camera 11 having high sensitivity characteristics in the near-infrared region and the illumination device 12 that irradiates near-infrared light, the vehicle is illuminated by near-infrared light even when the interior of the vehicle is dark, such as at night or in a tunnel. The driver's face can be photographed with high sensitivity. The camera 11 transmits face image data to the driver monitor ECU 20 every time an image for one frame is captured. The camera 11 and the illumination device 12 are arranged at a position where the driver's face image can be taken, for example, a steering upper column or a meter panel with the optical axis facing the driver's face.

  The GPS 13 receives a GPS signal from a GPS satellite and detects the position of the vehicle including the latitude and longitude, and the current date and time. Then, the GPS 13 sequentially transmits the detected vehicle position and date / time to the driver monitor ECU 20.

  The solar radiation sensor 14 is a sensor that measures the total solar radiation amount. The solar radiation sensor 14 sequentially transmits the measured solar radiation amount to the driver monitor ECU 20. Generally, a solar radiation sensor used to automatically turn on a headlight and a small lamp according to the brightness around the vehicle is installed on the dashboard of the vehicle. As the solar radiation sensor 14, the solar radiation sensor for the auto light may be used.

  The driver monitor ECU 20 is configured as a computer including a CPU, a memory such as a ROM and a RAM, an I / O, and a bus line connecting these. The memory includes a DB 26 (storage means) in which the altitude and direction of the sun with respect to latitude, longitude, and date / time are stored.

  Further, the driver monitor ECU 20 implements the functions of the face image recognition unit 21, the state detection unit 22, the determination unit 23, and the reliability calculation unit 24 by the CPU executing various programs stored in the ROM.

  The face image recognition unit 21 recognizes the driver's face image taken by the camera 11. Specifically, edges are extracted from the driver's face image photographed by the camera 11, and facial feature points such as eyebrows, upper and lower eyelids, iris portions of the eyes, nostrils, and mouth corners are detected from the extracted edges. The brightness of the contour of each part of the face is larger than that of the skin. Therefore, the outline of each part of the face, that is, the feature point of the face can be obtained from the extracted edge.

  Further, the face image recognition unit 21 detects the face direction, line of sight, and eye opening of the driver from the position and shape of the detected feature points of the face. For example, the direction of the face is detected as being front if the feature point is symmetrical with respect to the reference center line, and is detected to be right if the feature point is on the right side with respect to the reference center line. The line of sight is detected as the front if the iris part exists in the center of the area surrounded by the upper and lower eyelids, and is detected as facing right if the iris part exists in the right part of the area surrounded by the upper and lower eyelids. The opening degree of the eye is detected as being open when the curvature of the upper eyelid is convex, and is detected as closing the eye when the curvature of the upper eyelid is convex. Alternatively, when the distance between the upper eyelid and the lower eyelid is wider than the distance between the upper eyelid and the eyebrows, it is detected that the eyes are open, and the distance between the upper eyelid and the lower eyelid is the distance between the upper eyelid and the eyebrows. If it is narrower, it may be detected that the eyes are closed. The face image recognition unit 21 transmits the detected face direction, line of sight, and eye opening of the driver to the state detection unit 22.

  The state detection unit 22 detects the state of the driver based on the driver's face orientation, line of sight, and eye opening detected by the face image recognition unit 21. The driver status is whether the driver is looking away and whether the driver is asleep. For example, when the time when the driver's face is not front is longer than a predetermined time, or when the driver's line of sight is not longer than the predetermined time, it is detected that the driver is looking away. On the other hand, when the time when the driver's face is not the front is shorter than the predetermined time and the time when the driver's line of sight is not the front is shorter than the predetermined time, the driver detects that he is not looking away. In addition, when the driver's eyes are closed for longer than the predetermined time, the driver detects that he is asleep, and when the driver's eyes are closed for less than the predetermined time, the driver is asleep. Detect if not. The face image recognition unit 21 and the state detection unit 22 constitute a state detection unit.

  The determination part 23 (determination means) determines the irradiation mode of sunlight on the face of the driver. Specifically, the determination unit 23 detects the heading of the vehicle from the change in the vehicle position sequentially transmitted from the GPS 13. Further, the determination unit 23 refers to the DB 26 to detect the altitude and direction of the sun at the vehicle position and date / time transmitted from the GPS 13. The determination unit 23 receives the amount of solar radiation measured by the solar radiation sensor 14.

  The determination unit 23 determines whether or not the amount of solar radiation measured by the solar radiation sensor 14 is less than a predetermined amount. This predetermined amount is less than the amount of solar radiation when it is clear or when there are thin clouds in the sky, and more than the amount of solar radiation when it is rainy or in the sky at night, in a tunnel, or when there is heavy clouds in the sky. . The determination unit 23 determines whether or not there is a possibility that the driver's face is exposed to sunlight based on the heading of the vehicle and the altitude and heading of the sun. That is, the determination unit 23 receives a sufficient amount of sunlight to reduce the detection accuracy of the driver's face orientation, line of sight, and eye opening by the face image recognition unit 21, and thus the detection accuracy of the driver state by the state detection unit 22. Then, it is determined whether or not there is a possibility of hitting the user's face. Then, the determination unit 23 outputs the determination result regarding the position of the vehicle, the azimuth of the vehicle, the date and time, the predetermined information including the sun altitude and the azimuth, and the manner of irradiating the driver's face with sunlight. Send to. The GPS 13, the determination unit 23, and the DB 26 constitute an information detection unit.

  The reliability calculation unit 24 (reliability calculation means) determines that the determination result received from the determination unit 23 is that the amount of solar radiation measured by the solar radiation sensor 14 is less than a predetermined amount, or the driver's face is exposed to sunlight. If there is no possibility, the reliability of the driver state detected by the state detection unit 22 is calculated as a maximum value. In addition, the reliability calculation unit 24 determines that the determination result received from the determination unit 23 is greater than the predetermined amount of solar radiation and the driver's face may be exposed to sunlight. The higher the possibility of sunlight, the lower the reliability of the driver state detected by the state detection unit 22.

  The possibility of sunlight hitting the driver's face is highly correlated with the heading toward the vehicle and the altitude and heading of the sun at the current position and date. That is, the possibility that sunlight hits the driver's face has a high correlation with the relative position of the sun with respect to the vehicle. Therefore, the reliability calculation unit 24 calculates the reliability of the driver state based on the predetermined information received from the determination unit 23.

  When the altitude of the sun is kept constant at a sufficiently low altitude, when the heading of the vehicle coincides with the heading of the sun, the possibility of sunlight hitting the driver's face is the highest. The difference between the heading and the lower the possibility that the driver's face will be exposed to sunlight. Therefore, the reliability calculation unit 24 calculates the reliability of the driver state detected by the state detection unit 22 as the difference between the heading of the vehicle and the sun position at the current position and date / time is smaller.

  In addition, when the azimuth of the sun is constant at the azimuth toward the vehicle, the lower the altitude of the sun, the higher the possibility that sunlight will hit the driver's face. Therefore, the reliability calculation unit 24 calculates the reliability of the driver state detected by the state detection unit 22 as the sun altitude at the current position and date is lower.

  Also, if the sun's altitude is constant at a sufficiently low altitude, when the sun's heading is on the driver's side of the vehicle, the sun's head is closer to the driver's seat than when the sun's heading is on the passenger's seat The chance of hitting is high. Therefore, the reliability calculation unit 24 determines the state detection unit 22 when the sun direction at the current position and date is on the side of the driver's seat of the vehicle, compared with when the sun direction is on the side of the passenger seat of the vehicle. The reliability of the state of the driver detected by is calculated low.

  Furthermore, when the driver's face is exposed to sunlight, the greater the amount of solar radiation, the lower the recognition accuracy of the driver's face image by the face image recognition unit 21 and thus the detection accuracy of the driver's state by the state detection unit 22. Therefore, the reliability calculation unit 24 calculates the reliability of the driver state detected by the state detection unit 22 as the amount of solar radiation measured by the solar radiation sensor 14 increases. The reliability calculation unit 24 transmits the calculated reliability of the driver state to the monitor 31 and the speaker 32.

  The monitor 31 and the speaker 32 transmit the reliability of the user's state detected by the state detection unit 22 based on the sunlight irradiation mode determined by the determination unit 23. Specifically, when the reliability calculated by the reliability calculation unit 24 is smaller than a threshold (for example, 50%), the monitor 31 displays that the monitoring system 10 cannot be used on the screen as shown in FIG. The speaker 32 outputs an alarm sound. The speaker 32 may output by voice that the monitoring system 10 cannot be used. The above-described reliability calculation unit 24, the monitor 31, and the speaker 32 constitute transmission means.

  Further, the speaker 32 outputs an alarm to the driver when the state detection unit 22 detects the driver's state as a dozing state or a looking-aside state. The alarm may be a sound for prompting attention or awakening, or may be an alarm sound different from that for notifying that the reliability is low.

  The external storage device 33 stores the face image of the driver photographed by the camera 11 and the reliability calculated by the reliability calculation unit 24 in association with each other.

  Next, a processing procedure for notifying the driver of the reliability will be described with reference to the flowchart of FIG. This process is repeatedly executed by the driver monitor ECU 20 at predetermined intervals. The determination unit 23 performs the processes of S11 to S15, and the reliability calculation unit 24 performs the processes of S16 to S18.

  First, in S <b> 11, the determination unit 23 acquires the amount of solar radiation measured by the solar radiation sensor 14. Subsequently, in S12, the determination unit 23 determines whether or not the amount of solar radiation acquired in S11 is greater than a threshold value (predetermined amount). If the amount of solar radiation is less than the threshold, even if the user's face is exposed to sunlight, the image recognition accuracy by the face image recognition unit 21 and thus the detection accuracy of the driver state by the state detection unit 22 are not lowered. On the other hand, if the amount of solar radiation is greater than the threshold, when the user's face is exposed to sunlight, the image recognition accuracy by the face image recognition unit 21 and the driver state detection accuracy by the state detection unit 22 are increased. May decrease.

  For example, the amount of solar radiation when it is clear or when there are thin clouds in the sky is greater than the threshold, and the amount of solar radiation when there is heavy clouds in the night, in the tunnel, in the rain, or in the sky is the amount of solar radiation. Is less than the threshold. If it is determined that the amount of solar radiation is greater than the threshold (YES), the process proceeds to S12. If it is determined that the amount of solar radiation is less than the threshold (NO), the process proceeds to S16.

  If it is determined in S12 that the amount of solar radiation is less than the threshold value, there is no possibility that the detection accuracy of the driver state by the state detection unit 22 will be reduced regardless of whether the driver's face is exposed to sunlight. Therefore, in S16, the reliability calculation unit 24 sets the reliability of the driver state detected by the state detection unit 22 to 100% (maximum value) regardless of the possibility that the driver's face is exposed to sunlight. calculate. That is, the reliability calculation unit 24 calculates the reliability of the driver state detected by the state detection unit 22 to 100% based on the influence of sunlight.

  On the other hand, if it is determined in S12 that the amount of solar radiation is greater than the threshold, the accuracy of detection of the driver state by the state detection unit 22 may decrease when sunlight hits the driver's face. Therefore, the determination unit 23 performs the processes of S13 to S15, and determines whether or not there is a possibility that sunlight hits the driver's face.

  First, in S <b> 13, the determination unit 23 acquires the position and date of the vehicle detected by the GPS 13, and acquires the heading of the vehicle from the acquired position change of the vehicle. Subsequently, in S14, the determination unit 23 acquires, from the DB 26, the altitude and direction of the sun at the vehicle position and date and time acquired in S13.

  Subsequently, in S15, the determination unit 23 determines whether or not there is a possibility that sunlight hits the driver's face from the vehicle position and vehicle heading acquired in S13 and the sun altitude and heading acquired in S14. To determine. If it is determined that the driver's face may be exposed to sunlight (YES), the process proceeds to S17. If it is determined that the driver's face is not likely to be exposed to sunlight (NO), S16 Proceed to processing.

  If it is determined in S15 that there is no possibility that the driver's face will be exposed to sunlight, even if the amount of solar radiation is larger than the threshold value, the detection accuracy of the driver state by the state detection unit 22 may not be reduced. Therefore, in S16, the reliability calculation unit 24 calculates the reliability of the driver state detected by the state detection unit 22 to 100% (maximum value) regardless of the amount of solar radiation. That is, the reliability calculation unit 24 calculates the reliability of the driver state detected by the state detection unit 22 to 100% based on the influence of sunlight.

  On the other hand, when it is determined in S15 that the driver's face may be exposed to sunlight, there is a risk that the detection accuracy of the driver state by the state detection unit 22 may be reduced. Therefore, in S17, the reliability calculation unit 24 determines the amount of sunlight that may hit the driver's face based on the amount of solar radiation acquired by the determination unit 23 in S11 and the predetermined information acquired in S13 and S14. The greater the number of, the lower the reliability of the driver state detected by the state detector 22 is calculated.

  Specifically, the greater the amount of solar radiation measured by the solar radiation sensor 14, the lower the reliability is calculated. Further, the smaller the difference between the heading of the vehicle and the heading of the sun, the lower the reliability is calculated. In addition, the lower the solar altitude, the lower the reliability. Further, when the sun direction is on the driver's seat side, the reliability is calculated lower than when the sun direction is on the passenger seat side. The reliability calculation unit 24 calculates the reliability based on a reliability map set in advance for each of the four parameters, integrates the reliability, and detects the driver state detected by the state detection unit 22. The reliability of is calculated.

  Subsequently, in S18, the reliability calculation unit 24 determines the reliability of the driver state detected by the state detection unit 22 by the monitor 31 and the speaker 32 when the calculated reliability is lower than a threshold value (for example, 50%). Tell the driver that the degree is low.

  According to this embodiment described above, the following effects are obtained.

  If the driver's face is exposed to ambient light, noise may be mixed in the face image captured by the camera 11, and the state detection unit 22 may deteriorate the user state detection accuracy. Therefore, the sunlight irradiation mode on the driver's face is determined, and the reliability of the detected driver state is transmitted to the driver based on the determined sunlight irradiation mode. Therefore, the driver can recognize whether or not the user's state detected by the state detection unit 22 can be trusted based on the reliability based on the sunlight irradiation mode, that is, the disturbance light mixing mode in the face image. . Therefore, it is possible to suppress the driver from being overconfident or distrustful with respect to the monitoring system 10.

  The state of the driver detected based on the face image is higher as the possibility that the driver's face is exposed to sunlight, that is, the possibility that noise is mixed in the face image taken by the camera 11 is higher. Is calculated with low reliability. Therefore, the driver can recognize whether or not the driver's state detected by the state detection unit 22 can be trusted according to the possibility that the face is exposed to sunlight.

  -The possibility that sunlight hits the driver's face has a high correlation with the heading of the vehicle and the altitude and heading of the sun at the current position and date. The altitude and direction of the sun can be calculated from the current position and date of the vehicle. Therefore, the reliability of the user's state detected by the state detection unit 22 can be calculated based on predetermined information including the position of the vehicle, the heading of the vehicle, and the date and time.

  ・ When the altitude of the sun is constant, the possibility that sunlight will hit the driver's face is the highest when the heading of the vehicle coincides with the heading of the sun. The more different, the less likely the sunlight will hit the driver's face. Therefore, the smaller the difference between the heading of the vehicle and the heading of the sun, the lower the reliability of the driver state detected by the state detector 22 can be calculated.

  -When the direction of the sun is fixed, the lower the altitude of the sun, the higher the possibility that the user's face will receive sunlight. Therefore, the lower the altitude of the sun, the lower the reliability of the detected user state.

  -When the altitude of the sun is kept constant, there is a higher possibility that sunlight will hit the driver's face when the sun's direction is on the driver's side of the vehicle than when it is on the passenger's side. Therefore, the reliability of the state of the driver detected by the state detection unit 22 can be calculated lower when the direction of the sun is on the side of the driver's seat than on the side of the passenger seat.

  If the sun is present at an altitude and direction where the driver's face is not exposed to sunlight, noise is not mixed in the face image captured by the camera 11, so that the detection accuracy of the driver state based on the face image does not deteriorate. Therefore, when the sun at the current position and date and time is at an altitude and direction where sunlight does not hit the driver's face, the reliability of the driver state detected by the state detection unit 22 can be calculated to the maximum value.

  -When sunlight hits the driver's face, the greater the amount of solar radiation, the more difficult it is to detect the driver's state. Thus, the greater the amount of solar radiation, the lower the reliability of the driver state detected by the state detector 22 can be calculated.

  ・ In rainy or cloudy, at night, the amount of solar radiation is less than the prescribed amount. In such a case, even if the driver's face is exposed to sunlight, the amount of solar radiation that hits the driver's face is sufficiently reduced, and the detection accuracy of the driver's state based on the face image does not decrease. Therefore, when the amount of solar radiation is smaller than the predetermined amount, the reliability of the driver state detected by the state detection unit 22 can be calculated to the maximum value regardless of the altitude and direction of the sun.

  -The altitude and direction of the sun according to the detected current position and date / time of the vehicle can be acquired from the DB 26.

  The face image photographed by the camera 11 and the reliability of the user state detected based on the face image are stored in the external storage device 33. Therefore, face images with low reliability can be excluded, and only face images with high reliability can be used for accident verification or the like. That is, the face image acquired during driving can be effectively used later.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows.

  When the reliability calculated by the reliability calculation unit 24 is higher than the threshold value, the driver may be notified that the reliability of the state of the driver detected by the state detection unit 22 is high. Alternatively, when the reliability calculated by the reliability calculation unit 24 is higher than the threshold, the driver is notified that the reliability is high, and when the reliability calculated by the reliability calculation unit 24 is lower than the threshold. The driver may be notified that the reliability is low. Even in this case, the driver can recognize that the reliability is lowered when the reliability of the state of the driver detected by the state detection unit 22 is lowered. Alternatively, the reliability calculated by the reliability calculation unit 24 may be displayed on the monitor 31.

  The monitor 31 may not be provided. In that case, only the speaker 32 notifies the driver of the reliability of the state of the driver detected by the state detection unit 22. Further, the reliability of the driver state detected by the state detection unit 22 may be notified to the driver only by the monitor 31.

  -An indicator is installed in a place where the driver can easily recognize and the indicator is turned on when the reliability of the driver state detected by the state detection unit 22 is low or high, and the driver has low or high reliability. May be notified. Alternatively, depending on whether the reliability of the driver state detected by the state detection unit 22 is low or high, the indicator may be lit in different colors to notify the driver that the reliability is low and high.

  The DB 26 may be included in the external storage device 33. Further, the external storage device 33 may not be provided, and the face image captured by the camera 11 and the reliability calculated by the reliability calculation unit 24 may be stored in the memory of the driver monitor ECU 20.

  -The altitude and direction of the sun may be detected directly by a sensor. Moreover, you may detect directly the irradiation aspect of the sunlight to a driver with a sensor.

  -You may install the monitoring system 10 other than a vehicle.

  The user's face image irradiated with near-infrared light by the illumination device 12 is captured by the near-infrared camera 11, but the present invention is not limited to this. You may make it image | photograph a user's face image with the visible light camera arrange | positioned in the vehicle interior.

  DESCRIPTION OF SYMBOLS 11 ... Camera, 20 ... Driver monitor ECU, 21 ... Face image recognition part, 22 ... State detection part, 23 ... Determination part, 24 ... Reliability calculation part, 31 ... Monitor, 32 ... Speaker.

Claims (11)

Image acquisition means (11) for acquiring a user's face image;
State detection means (21, 22) for detecting the state of the user based on the face image acquired by the image acquisition means;
A determination means (23) for determining an irradiation mode of sunlight on the user's face;
Based on the sunlight irradiation mode determined by the determination unit, a transmission unit (24, 31, 32) for transmitting the reliability of the user state detected by the state detection unit;
A monitoring system comprising:   The said transmission means is provided with the reliability calculation means (24) which calculates low the reliability of the said user's state detected by the said state detection means, so that possibility that the sunlight of the said user is hitting is high. The monitoring system according to claim 1. The user is a vehicle driver;
Comprising information detecting means (13, 23, 26) for detecting predetermined information including the position of the vehicle, the heading of the vehicle and the date and time;
The monitoring system according to claim 2, wherein the reliability calculation unit calculates the reliability based on the predetermined information detected by the information detection unit.   The reliability calculation means calculates the reliability lower as the difference between the heading of the vehicle detected by the information detection means and the sun direction at the position and date detected by the information detection means is smaller. The monitoring system according to claim 3.   The monitoring system according to claim 3 or 4, wherein the reliability calculation unit calculates the reliability lower as the sun altitude at the position and date / time detected by the information detection unit is lower.   In the case where the azimuth of the sun at the position and date and time detected by the information detection means is lateral to the driver's seat of the vehicle, the reliability calculation means is when the azimuth of the sun is lateral to the passenger seat of the vehicle. The monitoring system according to any one of claims 3 to 5, wherein the reliability is calculated to be lower.   The reliability calculation means calculates the reliability to the maximum value when the sun at the position and date / time detected by the information detection means exists at an altitude and direction where the user's face does not receive sunlight. The monitoring system according to claim 3. The user is a vehicle driver;
The solar radiation measuring means (14) for measuring the solar radiation amount is provided.
The monitoring system according to claim 2, wherein the reliability calculation unit calculates the reliability lower as the amount of solar radiation measured by the solar radiation measurement unit increases.   When the amount of solar radiation measured by the solar radiation measuring unit is less than a predetermined amount, the reliability calculating unit sets the reliability to the maximum value regardless of the possibility that the user's face is exposed to sunlight. The monitoring system according to claim 8, which is calculated as follows.   The monitoring system according to any one of claims 3 to 9, further comprising a storage device (26) in which the altitude and direction of the sun according to the position and date of the vehicle are stored.   The monitoring system according to any one of claims 2 to 10, further comprising a storage device (33) for storing the face image acquired by the image acquisition unit and the reliability corresponding to the face image.

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