Occupant monitoring camera

Abstract

The purpose of the present disclosure is to provide an occupant monitoring camera capable of emitting light of uniform illuminance onto an occupant in a vehicle interior. This occupant monitoring camera according to the present disclosure comprises: an imaging unit that is attached to the front upper part of a vehicle and images the inside of the vehicle; a front row light source that emits light toward a front row in the vehicle; and a rear row light source that emits light toward a rear row in the vehicle. The direction of the optical axis of the rear row light source is different from the direction of the optical axis of the front row light source, and the emission angle of the rear row light source is different from the emission angle of the front row light source.

Description

Occupant monitoring camera

[0001] The present disclosure relates to an occupant monitoring camera that captures images of occupants inside a vehicle.

[0002] Passenger monitoring cameras not only capture images of passengers and the interior of the vehicle, but also use image sensing technology to detect the faces or bodies of passengers, primarily those seated in the driver's seat, passenger seat, and rear seats. To capture images of the entire vehicle interior, including the rear seats, infrared light must be irradiated into the interior, and a wide-angle camera lens and infrared-compatible image sensor must be used. To accurately detect the faces or bodies of passengers, it is desirable for the irradiance of the infrared light to be moderate and uniform within the capture range (the entire vehicle interior). If the irradiance of this infrared light is too bright, too dark, or has a large difference in brightness, the detection performance of the image sensing system may be reduced.

[0003] Conventionally, a light illumination system that illuminates light from near the rearview mirror toward the rear interior of a vehicle has been disclosed, with a drive recorder as an application example (see, for example, Patent Document 1). Specifically, Patent Document 1 discloses a light illumination system that can efficiently illuminate from a distant to a nearby object by simultaneously irradiating light from a first light illumination means having a narrow angle and high radiation intensity and a second light illumination means having a wide angle and low radiation intensity. Patent Document 1 also states that it is preferable that the illumination direction of the first light illumination means and the illumination direction of the second light illumination means are substantially the same direction.

[0004] Another example of a low-illuminance camera is an in-vehicle monitoring camera (see, for example, Patent Document 2). Specifically, Patent Document 2 discloses a low-illuminance camera that includes a first light-emitting unit with a wide emission angle and low radiation intensity, a second light-emitting unit with a narrow emission angle and high emission intensity, and means for controlling the emission intensity of each light-emitting unit so that the light-emitting unit with the highest emission intensity is switched sequentially in synchronization with the frame cycle of the image, and that creates one piece of moving image data from frame image data obtained with the emission patterns of each light-emitting unit.

[0005] JP 2021-121537 A JP 2012-5054 A

[0006] In Patent Document 1, when image sensing is performed using images obtained by emitting light from each light emitting means, the following problems can occur. That is, when the illumination angle of the first light emitting means is large, the light emitted from the first light emitting means and the light emitted from the second light emitting means overlap, making the center of the vehicle in the driver's seat and passenger seat (e.g., the shoulders of the occupants) too bright. Also, when the illumination angle of the first light emitting means is small, the outside of the vehicle in the rear seats becomes too dark. As such, in either case, there is a possibility that the detection performance of image sensing will be reduced.

[0007] In Patent Document 2, the frame rate decreases in images obtained using a means for controlling the light emission intensity of each light-emitting element, and therefore, when image sensing is performed on such images, the detection performance may decrease.

[0008] For the reasons described above, the techniques disclosed in Patent Documents 1 and 2 are not suitable for passenger monitoring cameras.

[0009] The present disclosure has been made to solve such problems, and aims to provide an occupant monitoring camera that can irradiate occupants in the vehicle cabin with light of uniform illuminance.

[0010] In order to solve the above problems, the occupant monitoring camera according to the present disclosure is attached to the upper front part of the vehicle and comprises an imaging unit that captures images of the interior of the vehicle, a front row light source that irradiates light onto the front row of the vehicle, and a rear row light source that irradiates light onto the rear row of the vehicle, wherein the direction of the optical axis of the rear row light source is different from the direction of the optical axis of the front row light source, and the illumination angle of the rear row light source is different from the illumination angle of the front row light source.

[0011] According to the present disclosure, it is possible to irradiate passengers in the vehicle cabin with light of uniform illuminance.

[0012] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0013] FIG. 1 is a cross-sectional view showing an example of the configuration of an occupant monitoring camera according to embodiment 1. FIG. 2 is a view for explaining the mounting position of an occupant monitoring camera according to embodiment 1. FIG. 3 is a view for explaining the mounting position of an occupant monitoring camera according to embodiment 1. FIG. 4 is a view for explaining the mounting position of an occupant monitoring camera according to embodiment 1. FIG. 5 is a view for explaining the mounting position of an occupant monitoring camera according to embodiment 1. FIG. 6 is a view for explaining the mounting position of an occupant monitoring camera according to embodiment 1. FIG. 7 is a view for explaining the direction of the optical axes and the illumination angles of each of a front row light source and a rear row light source according to the prior art. FIG. 8 is a view for explaining the direction of the optical axes and the illumination angles of each of a front row light source and a rear row light source according to the prior art. FIG. 9 is a view for explaining the direction of the optical axes and the illumination angles of each of a front row light source and a rear row light source according to embodiment 1. FIG. 10 is a cross-sectional view showing an example of the configuration of an occupant monitoring camera according to embodiment 2. FIG. 11 is a cross-sectional view showing an example of the configuration of an occupant monitoring camera according to embodiment 3. FIG. 12 is a cross-sectional view showing an example of the configuration of an occupant monitoring camera according to embodiment 4. FIG. 13 is a view for explaining the shape of a transparent member according to embodiment 4. FIG. 14 is a view for explaining the shape of a transparent member according to embodiment 4. FIG. 10 is a diagram showing the arrangement of the imaging unit, front row light source unit, and rear row light source unit in the occupant monitoring camera of embodiment 5.

[0014] First Embodiment <Configuration> FIG. 1 is a cross-sectional view showing an example of the configuration of an occupant monitoring camera 1 according to a first embodiment, as viewed from the vehicle width direction.

[0015] The occupant monitoring camera 1 comprises an imaging unit 2, a front row light source unit 3, a rear row light source unit 4, a control unit 5, a back member 6, a transparent member 7, a housing unit 8, and an inter-board connecting member 9.

[0016] The imaging unit 2 is composed of a camera lens 2a, a camera lens holder 2b, a sensor board 2c, an image sensor 2d, and an inter-board connector 2e, and captures images of the interior of the vehicle. The image sensor 2d is provided on the front surface of the sensor board 2c, and the inter-board connector 2e is provided on the back surface of the sensor board 2c. The image sensor 2d receives infrared light reflected from the front row light source 3b and the rear row light source 4b when they illuminate the interior of the vehicle, and converts the brightness of the received infrared light into an electrical signal. The camera lens 2a is provided on the side where the image sensor 2d receives the infrared light. The camera lens holder 2b holds the camera lens 2a.

[0017] The front row light source unit 3 is composed of a front row light source board 3a, a front row light source 3b, and an inter-board connector 3c, and irradiates light onto the driver's seat and passenger seat, which are the front rows of the vehicle. The front row light source 3b is provided on the front surface of the front row light source board 3a, and the inter-board connector 3c is provided on the back surface of the front row light source board 3a. The front row light source 3b is an LED (Light Emitting Diode) and irradiates infrared light onto the driver's seat and passenger seat.

[0018] The rear row light source unit 4 is composed of a rear row light source board 4a, a rear row light source 4b, and an inter-board connector 4c, and irradiates light onto the rear seats in the rear row of the vehicle. The rear row light source 4b is provided on the front surface of the rear row light source board 4a, and the inter-board connector 4c is provided on the back surface of the rear row light source board 4a. The rear row light source 4b is an LED, and irradiates infrared light onto the rear seats (seats other than the driver's seat and passenger seat).

[0019] The control unit 5 is composed of a control board 5a, an inter-board connector 5b, and an external connection connector 5c. The inter-board connector 5b is provided on the front surface of the control board 5a, and the external connection connector 5c is provided on the back surface of the control board 5a. The external connection connector 5c receives signals to control the front-row light sources 3b and the rear-row light sources 4b from the outside, and transmits electrical signals converted by the image sensor 2d to the outside.

[0020] The housing 8 is composed of a housing 8a, a sensor board holder 8b, a front row light source board holder 8c, a rear row light source board holder 8d, and a control board holder 8e. The sensor board holder 8b holds the sensor board 2c. The front row light source board holder 8c holds the front row light source board 3a. The rear row light source board holder 8d holds the rear row light source board 4a. The control board holder 8e holds the control board 5a.

[0021] The inter-board connection member 9 electrically connects the inter-board connection portion 2e of the imaging unit 2 to the inter-board connection portion 5b of the control unit 5, electrically connects the inter-board connection portion 3c of the front row light source unit 3 to the inter-board connection portion 5b of the control unit 5, and electrically connects the inter-board connection portion 4c of the rear row light source unit 4 to the inter-board connection portion 5b of the control unit 5.

[0022] The front surface of the housing 8 is covered with a transparent member 7. The transparent member 7 is a member that does not transmit visible light but transmits infrared light. The back surface of the housing 8 is covered with a back surface member 6.

[0023] <Installation Position of Occupant Monitoring Camera> The installation position of the occupant monitoring camera 1 will be explained using Figures 2 to 5. Figure 2 shows the case where the occupant monitoring camera 1 is installed on the dashboard inside the vehicle. Figure 3 is a diagram showing an image of the occupant monitoring camera 1 in Figure 2 capturing images of the interior of the vehicle. Figure 4 shows the case where the occupant monitoring camera 1 is installed on the overhead console inside the vehicle. Figure 5 is a diagram showing an image of the occupant monitoring camera 1 in Figure 4 capturing images of the interior of the vehicle. The areas surrounded by triangles in Figures 2 and 4 indicate the direction of the angle of view of the occupant monitoring camera 1.

[0024] In order to capture images of the faces of the occupants, the occupant monitoring camera 1 must be mounted at the front of the vehicle facing the rear of the vehicle. Furthermore, if the occupant monitoring camera 1 is not mounted above the vehicle, the faces of the rear seat occupants will often be hidden by the driver's seat and passenger seat in the images captured by the occupant monitoring camera 1.

[0025] When the occupant monitoring camera 1 is attached to the dashboard as shown in FIG. 2, the faces of the occupants in the rear seats are hidden by the driver's seat and passenger seat in the image captured by the occupant monitoring camera 1 as shown in FIG. 3.

[0026] On the other hand, when the occupant monitoring camera 1 is attached to the overhead console as shown in FIG. 4, the faces of the occupants in the rear seats are not hidden by the driver's seat or passenger seat in the images captured by the occupant monitoring camera 1 as shown in FIG. 5.

[0027] In this way, in order to capture and detect the heads, faces, and bodies of the occupants in the driver's seat and front passenger seat, and the heads, faces, and bodies of the occupants in the rear seats with a single occupant monitoring camera 1, the occupant monitoring camera 1 needs to be attached to the upper front part of the vehicle, such as the overhead console or the top of the windshield.

[0028] <Directions of Optical Axes and Illumination Angles of Front-Row Light Sources and Rear-Row Light Sources> The directions of optical axes and illumination angles of the front-row light sources 3b and rear-row light sources 4b will be described with reference to FIGS.

[0029] Fig. 6 is a diagram showing the direction of the optical axis and the illumination angle of each of the front row light source and the rear row light source according to the prior art, as viewed from the side of the vehicle. Fig. 7 is a diagram showing Fig. 6 as viewed from the top of the vehicle. Note that Figs. 6 and 7 show an example in which the rear row light source illuminates the second row seats, but it may also illuminate the third row seats.

[0030] As shown in Figures 6 and 7 , in the occupant monitoring camera 10 according to the prior art, the illumination range 11 of the front row light source and the illumination range 13 of the rear row light source are different, but the optical axis 12 of the front row light source and the optical axis 14 of the rear row light source are oriented in the same direction. Generally, the light emission intensity of a light source such as an LED tends to decrease as the angle from the optical axis direction increases. However, when the optical axis 12 of the front row light source and the optical axis 14 of the rear row light source are oriented in the same direction as in the prior art, if the illumination range 11 of the front row light source and the illumination range 13 of the rear row light source overlap, the center of the vehicle near the driver's seat and passenger seat, for example, the shoulders of the occupants, become too bright, raising the concern that the image or video corresponding to these bright areas (shown by the two circles in Figure 7 ) will be blown out.

[0031] To address these concerns in the prior art, as shown in Figures 8 and 9, in the occupant monitoring camera 1 according to embodiment 1, the direction of the optical axis 4e of the rear row light source 4b is different from the direction of the optical axis 3e of the front row light source 3b, and the illumination range 4d of the rear row light source 4b is different from the illumination range 3d of the front row light source 3b. The illumination range 4d of the rear row light source 4b is narrower than the illumination range 3d of the front row light source 3b so as to avoid overlapping the shoulders of the driver's seat and passenger seat occupants as much as possible. Furthermore, the illumination range 4d of the rear row light source 4b overlaps with the illumination range 3d of the front row light source 3b in a range that is farther up the vehicle from the direction of the optical axis 3e of the front row light source 3b (a range where the radiation intensity of the light emitted from the front row light source 3b is lower than that of the optical axis 3e). Here, the illumination range 4d is determined by the illumination angle of the light emitted from the rear row light source 4b. Similarly, the illumination range 3d is determined by the illumination angle of the light emitted from the front-row light source 3b. In other words, the illumination angle of the rear-row light source 4b is different from the illumination angle of the front-row light source 3b. This eliminates the blown-out highlights in images or videos that were a concern in conventional technology. Note that while Figures 8 and 9 show an example in which the rear-row light source illuminates the second-row seats, it may also illuminate the third-row seats.

[0032] <Effects> According to the first embodiment, the direction of the optical axis 4 e of the rear row light source 4 b is different from the direction of the optical axis 3 e of the front row light source 3 b, and the irradiation range 4 d (irradiation angle) of the rear row light source 4 b is different from the irradiation range 3 d (irradiation angle) of the front row light source 3 b. This reduces the overlap of the ranges with high radiation intensity of light emitted from the rear row light source 4 b and the front row light source 3 b. In other words, it becomes possible to irradiate occupants in the vehicle cabin with light of uniform illuminance. This reduces the illuminance difference of light within the shooting range, and obtains an image with uniform brightness.

[0033] 1 illustrates a configuration in which the imaging unit 2, front row light source unit 3, and rear row light source unit 4 are housed in the same housing unit 8, but the present invention is not limited to this. The imaging unit 2, front row light source unit 3, and rear row light source unit 4 may be housed in separate housing units as long as they are electrically connected to each other. However, the configuration illustrated in FIG. 1 reduces the space required to mount the occupant monitoring camera 1 on a vehicle, allowing for greater freedom in designing the vehicle structure surrounding the mounting of the occupant monitoring camera 1.

[0034] 2 to 9 show a vehicle with three rows of seats as an example, but the present invention is not limited to this and may be a vehicle with two rows of seats or a vehicle with four or more rows of seats.

[0035] <Embodiment 2> Figure 10 is a cross-sectional view showing an example of the configuration of an occupant monitoring camera 1 according to embodiment 2. In embodiment 2, the relationship between the light emitted from the front row light source 3b and the light emitted from the rear row light source 4b will be described. The configuration of the occupant monitoring camera 1 according to embodiment 2 is the same as that of the occupant monitoring camera 1 according to embodiment 1 (see Figure 1).

[0036] The infrared light 3f emitted from the front row light source 3b has a wider angle and weaker radiation intensity than the infrared light 4f emitted from the rear row light source 4b.

[0037] Generally, light intensity attenuates inversely proportional to the square of the distance to the illuminated object. The distance from the occupant monitoring camera 1 mounted at the front upper part of the vehicle to the occupants in the rear seats is greater than the distance to the occupants in the driver's seat and passenger seat. Therefore, by differentiating the radiation intensities of the front row light source 3b and the rear row light source 4b, it is possible to reduce the illuminance difference of light within the shooting range more than in the first embodiment. Other effects are the same as those in the first embodiment.

[0038] <Embodiment 3> Figure 11 is a cross-sectional view showing an example of the configuration of an occupant monitoring camera 1 according to embodiment 3. As shown in Figure 11, the occupant monitoring camera 1 according to embodiment 3 is characterized by including a front row light source board holder 8f and a rear row light source board holder 8g. The other configuration is the same as that of the occupant monitoring camera 1 according to embodiment 1 (see Figure 1), so detailed description will be omitted here.

[0039] The front-row light source board holding portion 8f has a board installation angle that is different from that of the front-row light source board holding portion 8c shown in Fig. 1. Specifically, the front-row light source board holding portion 8f has an inclined cross section. The same is true for the rear-row light source board holding portion 8g. In this way, by inclining the cross sections of the front-row light source board holding portion 8f and the rear-row light source board holding portion 8g, it is possible to arbitrarily adjust the orientation of the optical axes of the front-row light source 3b and the rear-row light source 4b.

[0040] The inclination of the cross section of each of the front row light source board holding portion 8 f and the rear row light source board holding portion 8 g may be realized by machining or by using a mold insert. Furthermore, screws or adhesive may be used to fix the front row light source board holding portion 8 f to the front row light source board 3 a and the rear row light source board holding portion 8 g to the rear row light source board 4 a.

[0041] Because the positional relationship between the occupant monitoring camera 1 and the driver's seat, passenger seat, and rear seats varies depending on the vehicle model, it may be necessary to adjust the direction of the optical axis of each of the front row light source 3b and the rear row light source 4b depending on the vehicle model in which the occupant monitoring camera 1 is installed. With the occupant monitoring camera 1 of embodiment 3, only new molds need to be prepared for the front row light source board holding portion 8f and the rear row light source board holding portion 8g, and the same molds as those used for the occupant monitoring camera 1 of embodiment 1 (see FIG. 1) can be used for the other components, thereby reducing the number of types of molds required and reducing the cost of manufacturing the occupant monitoring camera 1.

[0042] <Fourth Embodiment> Fig. 12 is a cross-sectional view showing an example of the configuration of an occupant monitoring camera 1 according to a fourth embodiment. As shown in Fig. 12, the occupant monitoring camera 1 according to the fourth embodiment is characterized in that a portion of the transparent member 7 is a curved portion 7a. The other configurations are basically the same as those of the occupant monitoring camera 1 according to the first embodiment (see Fig. 1), so detailed description will be omitted here. However, the rear row light source unit 4 has the same configuration as the rear row light source unit 4 of the occupant monitoring camera 1 according to the third embodiment (see Fig. 11). Note that the front row light source unit 3 and the rear row light source unit 4 may have the same configuration as those of either the first or second embodiment.

[0043] The infrared light emitted from each of the front row light sources 3b and the rear row light sources 4b is emitted in multiple directions, not just one. For example, as shown in Figure 13, if the flat portion of the transparent member 7 of the occupant monitoring camera 1 according to embodiments 1 and 2 is placed in front of the front row light sources 3b and the rear row light sources 4b, when the angle of incidence of the infrared light emitted from each of the front row light sources 3b and the rear row light sources 4b becomes large, the infrared light will be reflected by the surface of the transparent member 7, and the infrared light that passes through the transparent member 7 will be attenuated, which may prevent uniform radiation intensity from being obtained.

[0044] 14, when the curved surface portion 7a is disposed in front of the front-row light sources 3b and the rear-row light sources 4b, the curved surface portion 7a has a surface perpendicular to the direction of the infrared light emitted from each of the front-row light sources 3b and the rear-row light sources 4b. Therefore, most of the infrared light emitted from each of the front-row light sources 3b and the rear-row light sources 4b is transmitted without being reflected by the curved surface portion 7a. This allows for uniform radiation intensity.

[0045] <Fifth Embodiment> Figure 15 is a diagram showing the arrangement of the imaging unit 2, front row light source unit 3, and rear row light source unit 4 in an occupant monitoring camera 1 according to a fifth embodiment. As shown in Figure 15, the occupant monitoring camera 1 according to the fifth embodiment is characterized in that the imaging unit 2, front row light source unit 3, and rear row light source unit 4 are arranged side by side in the longitudinal direction of the vehicle. The rest of the configuration is the same as that of the occupant monitoring camera 1 according to any one of the first to fourth embodiments (see Figures 1, 10, 11, and 12), and therefore detailed description thereof will be omitted here.

[0046] The occupant monitoring camera 1 is mounted, for example, on an overhead console (see FIG. 4). The image sensor 2d of the imaging unit 2, the front row light source 3b of the front row light source unit 3, and the rear row light source 4b of the rear row light source unit 4 are aligned in the longitudinal direction of the vehicle. This allows the irradiation ranges of the infrared light emitted from the front row light source 3b and the rear row light source 4b to be symmetrical across the vehicle width. This reduces the illuminance difference within the imaging range, allowing for the acquisition of images with uniform brightness.

[0047] Within the scope of the present disclosure, the embodiments can be freely combined, modified, or omitted as appropriate.

[0048] Although the present disclosure has been described in detail, the above description is illustrative in all respects and is not restrictive. It is understood that countless variations not illustrated can be envisioned.

[0049] DESCRIPTION OF SYMBOLS 1 Occupant monitoring camera, 2 Imaging unit, 2a Camera lens, 2b Camera lens holder, 2c Sensor board, 2d Image sensor, 2e Board-to-board connection unit, 3 Front row light source unit, 3a Front row light source board, 3b Front row light source, 3c Board-to-board connection unit, 3d Irradiation range, 3e Optical axis, 3f Infrared light, 4 Rear row light source unit, 4a Rear row light source board, 4b Rear row light source, 4c Board-to-board connection unit, 4d Irradiation range, 4e Optical axis, 4f Infrared light, 5 Control unit, 5a Control board, 5b Board-to-board connection unit, 5c External connection connector, 6 Back member, 7 Transparent member, 7a Curved surface unit, 8 Housing unit, 8a Housing, 8b Sensor board holding unit, 8c Front row light source board holding unit, 8d Rear row light source board holding unit, 8e Control board holding unit, 8f Front row light source board holder, 8g rear row light source board holder, 9 inter-board connection member, 10 occupant monitoring camera, 11 illumination range, 12 optical axis, 13 illumination range, 14 optical axis.

Claims

1. an imaging unit attached to an upper front portion of a vehicle and configured to capture an image of the interior of the vehicle; a front row light source that irradiates light onto the front row of the vehicle; a rear row light source that irradiates light onto a rear row of the vehicle; Equipped with An occupant monitoring camera, wherein the substrate and optical axis direction of the rear row light source are different from the optical axis direction of the front row light source, and the substrate and illumination angle of the rear row light source are different from the illumination angle of the front row light source.

2. The occupant monitoring camera according to claim 1 , wherein the front row light source and the rear row light source are housed in the same housing.

3. The occupant monitoring camera according to claim 1 , wherein the light emitted from the front row light source has a wider angle and a weaker radiation intensity than the light emitted from the rear row light source.

4. The occupant monitoring camera according to claim 1 , wherein the directions of the optical axes of the front row light sources and the rear row light sources are adjustable.

5. The occupant monitoring camera according to claim 1 , further comprising a transparent member having a surface perpendicular to the direction of light emitted from each of the front row light sources and the rear row light sources.

6. The occupant monitoring camera according to claim 1 , wherein the imaging unit, the front row light source, and the rear row light source are arranged side by side in a longitudinal direction of the vehicle.