Driver monitoring device

Abstract

The present invention provides a driver monitoring device that can determine the steering angle based on captured images, regardless of the driver's grip position on the steering wheel. [Solution] The driver monitoring device comprises a camera that acquires captured images of a shooting area including the driver's face, and a control unit that monitors the driver's state based on the captured images. The camera is positioned so that the face and at least a portion of the vehicle's steering wheel are included in the shooting area. The steering wheel is marked with marks to identify the steering angle of the steering wheel, so that at least three marks are included in the shooting area regardless of the steering wheel's rotation position. The control unit identifies the steering angle based on the marks included in the captured images.

Description

Technical Field

[0001] The present invention relates to a driver monitoring device that monitors the driver's state based on a captured image including the driver's face.

Background Art

[0002] Conventionally, a driver monitoring device that monitors the driver's state based on a captured image including the driver's face captured by a camera has been known. Further, the steering device described in Patent Document 1 (hereinafter referred to as the "conventional device") identifies the rotation locus of the steering wheel based on the captured image captured by the camera, and identifies the steering angle of the steering wheel based on the rotation locus. Specifically, the camera of the conventional device captures a captured area including the driver and the steering wheel. One mark is provided on the steering wheel, and the conventional device identifies the rotation locus of the steering wheel by tracking the mark.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] Depending on the gripping position of the driver's steering wheel, there is a possibility that the driver's hand may hide the mark. When the driver's hand hides the mark, the conventional device cannot identify the rotation locus of the mark and thus cannot identify the steering angle.

[0005] The present invention has been made to address the above-described problems. That is, one object of the present invention is to provide a driver monitoring device that can identify the steering angle based on a captured image regardless of the gripping position of the driver's steering wheel.

[0006] The driver monitoring device of the present invention (hereinafter referred to as the "device of the present invention") is A camera (22) that acquires a captured image (PI) of the shooting area including the driver's face, The system includes a control unit (20) that monitors the driver's condition based on the captured images. The camera is positioned such that the face and at least a portion of the vehicle's steering wheel (SW) are included in the shooting area. The steering wheel is marked with marks (MK1 to MK6) for identifying the steering angle of the steering wheel, such that at least three of these marks are included in the imaging area, regardless of the rotational position of the steering wheel. The control unit is configured to determine the steering angle based on the marks included in the captured image.

[0007] According to the present invention, the imaging area will include at least three marks. Therefore, even if the driver's hands cover two marks, at least one mark will be captured in the image. Consequently, the present invention can determine the steering angle based on the captured image, regardless of the driver's grip position on the steering wheel. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic system configuration diagram of a driver monitoring device according to an embodiment of the present invention. [Figure 2] Figure 1 is an explanatory diagram of the markings on the steering wheel shown. [Figure 3] Figure 1 is an explanatory diagram of the image captured by the driver's seat camera. [Modes for carrying out the invention]

[0009] A driver monitoring device 10 (hereinafter referred to as "the device 10") according to an embodiment of the present invention is applied to a vehicle VA and comprises the components shown in Figure 1. In this specification, "ECU 20" is an electronic control device mainly comprising a microcomputer. The ECU 20 is also referred to as a control unit. The microcomputer includes a CPU (processor), ROM, RAM, and an interface (I / F), etc. The functions realized by the ECU 20 may be realized by multiple ECUs.

[0010] The driver's seat camera 22 acquires an image PI by capturing a shooting area that includes the face of the driver seated in the driver's seat DS. The driver's seat camera 22 may also be referred to simply as "camera". The driver's seat camera 22 is positioned so that its shooting area includes the driver's face and at least a portion of the steering wheel SW. For example, the driver's seat camera 22 may be positioned above the steering column SC or within the meter display MD.

[0011] The memory device 24 has a non-volatile memory area. A steering angle data storage unit 24a is set in this memory area. Steering angle data is stored in the steering angle data storage unit 24a. The steering angle data defines the relationship between the steering angle of the steering wheel SW and the position of a mark placed on the steering wheel SW as seen in the captured image PI when the steering wheel SW is at that steering angle.

[0012] The ECU 20 acquires captured image PI from the driver's seat camera 22 at predetermined intervals. Based on the captured image PI, the ECU 20 identifies the state of the driver's face. If the ECU 20 determines, based on the state of the driver's face, that the driver is distracted while driving, or if it determines, based on the state of the driver's face, that the driver is drowsy while driving, it issues a warning. For example, in the case of a warning, the ECU 20 outputs a warning sound from a speaker (not shown) installed in the vehicle and displays predetermined warning display elements on the meter display MD.

[0013] As shown in Figure 2, the steering wheel switch is circular in shape. At least three marks (six marks in the example shown in Figure 2) are placed on the side of the steering wheel switch facing the driver's seat camera 22. The marks are arranged so that three marks are included in the shooting area regardless of the rotational position of the steering wheel switch.

[0014] More specifically, as shown in Figure 2, marks MK1 to MK6 are arranged at equal angular intervals of 60 degrees on the side of the steering wheel switch facing the driver's seat camera 22. Mark MK1 (0 degrees) is located directly above the steering wheel switch in the neutral position, mark MK2 (60 degrees) is located 60 degrees counterclockwise from mark MK1, and mark MK3 (120 degrees) is located 60 degrees counterclockwise from mark MK2. Furthermore, mark MK4 (180 degrees) is located 60 degrees counterclockwise from mark MK3 (directly below the steering wheel switch in the neutral position), mark MK5 (240 degrees) is located 60 degrees counterclockwise from mark MK4, and mark MK6 (300 degrees) is located 60 degrees counterclockwise from mark MK5.

[0015] In the example shown in Figure 3, the shooting angle range θp, which represents the angle range of the steering wheel SW captured in the captured image PI, is 200 degrees. The angle range θm of the three marks placed at 60-degree intervals is 120 degrees. Since the shooting angle range θp is greater than the angle range θm, the three marks are always included in the shooting area regardless of the rotation position of the steering wheel SW. In other words, if the marks are arranged so that the angle range θm is less than or equal to the shooting angle range θp, the three marks will always be included in the shooting area.

[0016] The steering angle data described above registers the positions of three marks that appear in the captured image PI at 60-degree intervals, starting from a steering angle of "0 degrees". For example, when the steering angle is 0 degrees (i.e., when the steering wheel SW is in the neutral position), the steering angle data registers the positions of marks MK1, MK2, and MK6 as shown in Figure 3. When the steering wheel SW rotates 60 degrees in the direction of the arrow shown in Figure 3, the steering angle becomes 60 degrees. When the steering angle is 60 degrees, the steering angle data registers the positions of the marks such that mark MK2 is located at the position of mark MK1 in Figure 3, mark MK3 is located at the position of mark MK2 in Figure 3, and mark MK1 is located at the position of mark MK6 in Figure 3.

[0017] The ECU 20 determines the steering angle by comparing the position of the marks captured in the image PI acquired from the driver's seat camera 22 (captured mark positions) with the positions of the three marks registered in the steering angle data (registered mark positions). More specifically, the ECU 20 selects the steering angle in which the number of marks that match the marks captured in the image PI is the most numerous among the three marks registered in the steering angle data corresponding to the steering angle. Then, the ECU 20 obtains the deviation angle of the captured mark positions from the "registered mark positions corresponding to the selected steering angle in the steering angle data," and determines the steering angle based on the selected steering angle and the deviation angle in the steering angle data.

[0018] Depending on the driver's grip position on the steering wheel switch, the driver's hand may cover two of the marks. As mentioned above, the marks are positioned on the steering wheel switch so that all three marks are always included in the imaging area. Therefore, even if the driver's hand covers two of the marks, only one mark will be captured in the captured image PI. The ECU 20 can determine the steering angle based on this single mark captured in the captured image PI and the steering angle data. Thus, the device 10 can determine the steering angle based on the captured image PI regardless of the driver's grip position on the steering wheel.

[0019] Furthermore, this device 10 eliminates the need to install a conventional steering angle sensor. This reduces the manufacturing cost of the vehicle VA.

[0020] The driver's seat camera 22 may be an infrared camera. In this case, the mark is applied to the steering wheel SW using an infrared paint that reflects only infrared light. Further, the mark may be realized by a light emitting device such as an LED. In this case, the light emitting device disposed on the steering wheel SW emits light in a unique light emission pattern that is different from other light emitting devices.

[0021] Note that the number of marks applied to the steering wheel SW is not limited to six. It is sufficient that the steering wheel SW is provided with a number of marks such that at least three marks are included in the imaging area. That is, the marks may be arranged such that the angular range θm of the three marks is less than or equal to the imaging angle range θp.

[0022] The present device 10 is applicable to vehicles such as engine vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and electric vehicles, and is also applicable to autonomous vehicles.

Explanation of Reference Numerals

[0023] 10... Driver monitoring device, 22... Driver monitoring camera, SW... Steering wheel, MK1 to MK6... Marks.

Claims

[Claim 1] A camera that captures images of the area including the driver's face, The system includes a control unit that monitors the driver's condition based on the captured image, The camera is positioned such that the face and at least a portion of the vehicle's steering wheel are included in the shooting area. The steering wheel is marked with at least three marks for identifying the steering angle of the steering wheel, such that these marks are included in the imaging area regardless of the rotational position of the steering wheel. The control unit is configured to determine the steering angle based on the marks included in the captured image. Driver monitoring device.

Images