Image Recording Device

Abstract

To record a license plate of a following vehicle even when the following vehicle approaches one's own vehicle due to tailgate driving or the like.SOLUTION: An image recording device includes an electronic mirror camera 14 that captures the rear of a vehicle as a first image with a first angle of view, a back monitor camera 16 that captures the rear of the vehicle as a second image with a second angle of view wider than the first angle of view, and a drive recorder ECU 32 that records the first image when it is determined that the relative distance between the vehicle and a following vehicle is large to such an extent that the license plate of the following vehicle is within the first angle of view, and records the second image when it determines that the relative distance between the vehicle and the following vehicle is small to such an extent that the license plate of the following vehicle is not within the first angle of view.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an image recording device. [Background technology]

[0002] Patent Document 1 describes a technology that detects aggressive driving by a following vehicle based on the distance to the following vehicle, and records images of the rear when it is determined that the following vehicle is engaging in aggressive driving. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-205078 A Summary of the Invention [Problem to be solved by the invention]

[0004] When trying to realize a drive recorder function by recording images taken by an onboard camera used for vehicle driving assistance, etc., rather than a dedicated camera, in the vehicle's memory, when a vehicle engaging in aggressive driving approaches the vehicle's own vehicle, the license plate of the target vehicle is outside the field of view of the onboard camera, making it difficult to record properly.

[0005] The present disclosure has been made in consideration of the above-mentioned facts, and aims to provide an image recording device that is capable of recording the license plate of a following vehicle even when the following vehicle approaches the vehicle due to aggressive driving, etc. [Means for solving the problem]

[0006] The image recording device of the first aspect includes a first imaging unit that captures an image of the area behind the host vehicle as a first image with a first angle of view, a second imaging unit that captures an image of the area behind the host vehicle as a second image with a second angle of view wider than the first angle of view, and a recording control unit that records the first image when it determines that the relative distance between the host vehicle and a target vehicle behind the host vehicle is far enough that the license plate of the target vehicle falls within the first angle of view, and records the second image when it determines that the relative distance is close enough that the license plate of the target vehicle does not fall within the first angle of view.

[0007] In the first aspect, in addition to a first imaging unit that captures an image of the rear of the vehicle as a first image with a first angle of view, a second imaging unit that captures an image of the rear of the vehicle as a second image with a second angle of view wider than the first angle of view is included. Then, when the recording control unit determines that the relative distance between the vehicle and a target vehicle behind the vehicle is so close that the license plate of the target vehicle does not fit within the first angle of view, the recording control unit records a second image with a wider angle than the first image. This makes it possible to record the license plate of the following vehicle even if the following vehicle approaches the vehicle due to aggressive driving or the like.

[0008] In the second aspect, in the first aspect, the recording control unit determines, based on whether the license plate of the target vehicle can be recognized on the first image, whether the license plate of the target vehicle is far enough away to fit within the first angle of view, or whether the license plate of the target vehicle is close enough not to fit within the first angle of view.

[0009] According to the second aspect, it is possible to accurately determine whether the license plate of the target vehicle is far enough away to fit within the first angle of view, or close enough that the license plate of the target vehicle does not fit within the first angle of view.

[0010] In the third aspect, in the first aspect, the recording control unit determines whether the target vehicle's license plate is far enough away to fit within the first angle of view, or whether the target vehicle's license plate is close enough not to fit within the first angle of view, based on whether the relative distance measured by a ranging unit that measures the relative distance between the host vehicle and the target vehicle is greater than or equal to a predetermined distance.

[0011] According to the third aspect, it is possible to determine through simple processing whether the license plate of the target vehicle is far enough away to fit within the first angle of view, or close enough that the license plate of the target vehicle does not fit within the first angle of view.

[0012] A fourth aspect is that, in any of the first to third aspects, the first imaging unit is an imaging unit provided for displaying the first image on an electronic inner mirror, and the second imaging unit is an imaging unit provided for displaying the second image on a display unit when the vehicle is reversing.

[0013] In the fourth aspect, since imaging sections that are not dedicated to image recording are used as the first imaging section and the second imaging section, the cost of the image recording device according to the present disclosure can be reduced. Effect of the Invention

[0014] The present disclosure has the effect of making it possible to record the license plate number of a following vehicle even when the following vehicle approaches the vehicle due to aggressive driving or the like. [Brief description of the drawings]

[0015] [Figure 1] 1 is a block diagram showing a schematic configuration of an in-vehicle system according to an embodiment; [Diagram 2] FIG. 2 is an image diagram showing an example of the angle of view of the electronic mirror camera. [Diagram 3] FIG. 2 is a perspective view showing an example of an installation position of the electronic mirror camera. [Figure 4] FIG. 2 is a functional block diagram of a drive recorder ECU. [Diagram 5] 13 is a flowchart showing a camera switching process executed by a drive recorder ECU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An example of an embodiment of the present disclosure will be described in detail below with reference to the drawings. Fig. 1 shows an in-vehicle system 10 according to this embodiment. The in-vehicle system 10 is configured by connecting a plurality of devices and a plurality of ECUs (Electronic Control Units) to a system bus 12. The plurality of devices include an electronic mirror camera 14, a rear monitor camera 16, a clearance sonar 18, other cameras 20, and a shift lever 22. The plurality of ECUs also include an electronic mirror ECU 24, a rear monitor ECU 28, and a drive recorder ECU 32.

[0017] The electronic mirror camera 14 is a camera provided near the rear end of the vehicle for the purpose of capturing an image (moving image) to be displayed on the electronic inner mirror 26 (described later), and captures an image of the rear of the vehicle as a first image with a first angle of view. The first angle of view of the electronic mirror camera 14 is set such that the turn signal of a following vehicle that is a distance X (for example, about 15.5 m) away from the vehicle falls within the first angle of view, in accordance with the field of view of an optical inner mirror (shown as "mirror mirror" in FIG. 2) (see the range shown as "digital inner mirror" in FIG. 2). For this reason, the electronic mirror camera 14 has a blind spot in a relatively short range behind the vehicle.

[0018] If the vehicle has a back door as shown in FIG. 3(A), the more specific installation location of the electronic mirror camera 14 is near the license plate (see "Position A" in FIG. 3(A)), or on the interior side of the rear window (a position corresponding to the wiping range of the rear wiper: see "Position B" in FIG. 3(A)), or near the rear spoiler (see "Position C" in FIG. 3(A)). If the vehicle does not have a back door as shown in FIG. 3(B), the more specific installation location of the electronic mirror camera 14 is near the license plate (see "Position A" in FIG. 3(B). The electronic mirror camera 14 is an example of a first imaging unit in the present disclosure.

[0019] The rear monitor camera 16 is a camera provided near the rear end of the vehicle for the purpose of capturing an image (moving image) to be displayed on a display 30 (described later) when the vehicle is reversing, and captures an image of the rear of the vehicle as a second image with a second angle of view wider than the first angle of view. The focal length of the lens of the rear monitor camera 16 is set so that a part of the rear bumper of the vehicle is captured as the second image so that the second angle of view can be used as a landmark when the vehicle is reversing. The more specific installation position of the rear monitor camera 16 is, for example, near the license plate (see "position A" in Figures 3(A) and (B)). The rear monitor camera 16 is an example of a second imaging unit in the present disclosure.

[0020] The clearance sonar 18 includes a plurality of ultrasonic sensors provided near the front end and the rear end of the vehicle for the purpose of assisting driving operations such as parking the vehicle. Each ultrasonic sensor detects the distance between the vehicle and an obstacle present around the vehicle by ultrasonic waves. The detection result of an obstacle by the ultrasonic sensor of the clearance sonar 18 is used to output an alarm as necessary when a driving operation such as parking the vehicle is performed, or to perform intervention brake control to brake and decelerate the vehicle on behalf of the driver. The clearance sonar 18 is an example of a distance measuring unit in the present disclosure.

[0021] The other cameras 20 include a plurality of cameras that capture images of the areas around the vehicle, in front and to the sides, that are not captured by the electronic mirror camera 14.

[0022] The electronic mirror ECU 24 is connected to an electronic inner mirror 26 that is provided in the vehicle interior at a position spaced above the vehicle from the center of the instrument panel of the vehicle. The electronic mirror ECU 24 causes the electronic inner mirror 26 to display a first image captured by the electronic mirror camera 14 while the ignition switch of the vehicle is on.

[0023] The rearview monitor ECU 28 is connected to a display 30 provided in the center of the instrument panel of the vehicle interior. The rearview monitor ECU 28 displays the second image captured by the rearview monitor camera 16 on the display 30 while the shift lever 22 is in the reverse position.

[0024] The drive recorder ECU 32 includes a CPU (Central Processing Unit) 34, a memory 36 such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a non-volatile storage unit 38 such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive), and a communication unit 40. The CPU 34, the memory 36, the storage unit 38, and the communication unit 40 are connected to each other via an internal bus 42 so as to be able to communicate with each other.

[0025] The storage unit 38 of the drive recorder ECU 32 stores a camera switching program 44 and is provided with an image recording area 46. While the ignition switch of the vehicle is on, the drive recorder ECU 32 records the first image captured by the electronic mirror camera 14 or the second image captured by the rear monitor camera 16, and the images captured by the other cameras 20 in the image recording area 46 as drive recorder images.

[0026] 4 and performs a camera switching process described later, by the camera switching program 44 being read from the storage unit 38 and loaded into the memory 36, and the camera switching program 44 loaded into the memory 36 being executed by the CPU 34. The drive recorder ECU 32, together with the electronic mirror camera 14 and the rear monitor camera 16, is an example of an image recording device according to the present disclosure.

[0027] Next, as an operation of this embodiment, a camera switching process executed by the drive recorder ECU 32 while the ignition switch of the host vehicle is on will be described with reference to FIG.

[0028] In step 70 of the camera switching process, the recording control unit 48 of the drive recorder ECU 32 acquires a first image captured by the electronic mirror camera 14 from the electronic mirror camera 14. In step 72, the recording control unit 48 performs a predetermined image processing on the first image acquired in step 70, thereby attempting to determine whether or not the license plate of the vehicle following the host vehicle can be recognized in the first image.

[0029] In step 74, the recording control unit 48 acquires from the clearance sonar 18 the relative distance L between the host vehicle and the following vehicle, which is detected by an ultrasonic sensor, of the multiple ultrasonic sensors included in the clearance sonar 18, that has a detection range behind the host vehicle.

[0030] In step 76, the recording control unit 48 determines whether or not a first condition is satisfied, that is, the license plate of the following vehicle cannot be recognized on the first image, and a second condition is satisfied, that is, the relative distance L between the host vehicle and the following vehicle is less than a predetermined distance. Note that the predetermined distance in the determination in step 76 is set to a value equivalent to the inter-vehicle distance between the host vehicle and the following vehicle when the host vehicle is too close for the license plate of the following vehicle to be included within the first angle of view of the electronic mirror camera 14.

[0031] In step 76, if at least one of the first condition and the second condition is not satisfied, it can be determined that the following vehicle is far enough away from the host vehicle that the license plate of the following vehicle falls within the first angle of view of the electronic mirror camera 14. Therefore, if the determination in step 76 is negative, the process proceeds to step 78. Then, in step 78, the recording control unit 48 acquires a first image (moving image) from the electronic mirror camera 14, and in step 82, the recording control unit 48 records the acquired first image in the image recording area 46 as a drive recorder image behind the host vehicle.

[0032] On the other hand, in step 76, if both the first condition and the second condition are satisfied, it can be determined that the following vehicle is approaching so close that the license plate of the following vehicle does not fit within the first angle of view of the electronic mirror camera 14. A typical example of such a situation is when the following vehicle is engaging in aggressive driving. When the distance between the vehicle and the following vehicle becomes small due to aggressive driving or the like, the license plate of the following vehicle enters the blind spot area of ​​the electronic mirror camera 14, making it impossible to leave evidence to identify the aggressive following vehicle.

[0033] Therefore, if the determination in step 76 is positive, the process proceeds to step 80. Then, in step 80, the recording control unit 48 acquires a second image (moving image) from the rear monitor camera 16, and in step 82, the recording control unit 48 records the acquired second image in the image recording area 46 as a drive recorder image behind the vehicle. This makes it possible to leave evidence for identifying the following vehicle that engaged in aggressive driving.

[0034] As described above, in this embodiment, the image recording device includes an electronic mirror camera 14 that captures an image of the rear of the vehicle as a first image with a first angle of view, a back monitor camera 16 that captures an image of the rear of the vehicle as a second image with a second angle of view wider than the first angle of view, and a recording control unit 48 that records the first image when it is determined that the relative distance between the vehicle and the following vehicle is such that the license plate of the following vehicle falls within the first angle of view, and records the second image when it is determined that the relative distance between the vehicle and the following vehicle is such that the license plate of the following vehicle does not fall within the first angle of view. This makes it possible to record the license plate of the following vehicle even if the following vehicle approaches the vehicle due to aggressive driving or the like.

[0035] Furthermore, in this embodiment, the recording control unit 48 judges whether the license plate of the following vehicle is far enough away to be included within the first angle of view or close enough not to be included within the first angle of view based on whether the license plate of the following vehicle can be recognized on the first image. This makes it possible to accurately judge whether the license plate of the following vehicle is far enough away to be included within the first angle of view or close enough not to be included within the first angle of view.

[0036] In this embodiment, the recording control unit 48 judges whether the license plate of the following vehicle is far enough away to be included within the first angle of view or close enough not to be included within the first angle of view based on whether the relative distance between the vehicle and the following vehicle measured by the clearance sonar 18 that measures the relative distance between the vehicle and the following vehicle is equal to or greater than a predetermined distance. This makes it possible to judge by simple processing whether the license plate of the following vehicle is far enough away to be included within the first angle of view or close enough not to be included within the first angle of view.

[0037] In this embodiment, the electronic mirror camera 14 is an imaging unit provided for displaying a first image on the electronic inner mirror 26, and the back monitor camera 16 is an imaging unit provided for displaying a second image on the display 30 when the vehicle is reversing. This makes it possible to reduce the cost of the image recording device.

[0038] In the above, the second image is recorded when the determination in step 76 in FIG. 5 is positive, and the first image is recorded when the determination is negative. However, in order to prevent the second image and the first image from frequently switching between them while the following vehicle is tailgating, the determination in step 76 in FIG. 5 (image switching control) may have hysteresis.

[0039] In the above, the embodiment has been described in which it is determined that the license plate of the target vehicle is too close to be included in the first angle of view when the first condition that the license plate of the target vehicle cannot be recognized on the first image is satisfied and the second condition that the relative distance between the vehicle and the target vehicle is less than a predetermined distance is satisfied, but the present disclosure is not limited to this. For example, it may be determined that the license plate of the target vehicle is too close to be included in the first angle of view when the first condition is satisfied without performing a determination corresponding to the second condition, and that the license plate of the target vehicle is far enough to be included in the first angle of view when the first condition is not satisfied. Also, it may be determined that the license plate of the target vehicle is too close to be included in the first angle of view when the second condition is satisfied without performing a determination corresponding to the first condition, and that the license plate of the target vehicle is far enough to be included in the first angle of view when the second condition is satisfied.

[0040] Further, in the above embodiment, a moving image is recorded as the second image, but the present invention is not limited to this, and a still image may be recorded as the second image. [Explanation of symbols]

[0041] 10. In-vehicle systems 14 Electronic mirror camera (first imaging unit) 16 Rear monitor camera (second imaging unit) 18 Clearance sonar (ranging unit) 26 Electronic rearview mirror 30 Display (Display unit) 32 Drive recorder ECU 46 Image recording area

Claims

1. a first imaging unit that captures an image of an area behind the vehicle as a first image with a first angle of view; a second imaging unit that captures an image of an area behind the vehicle as a second image with a second angle of view that is wider than the first angle of view; a recording control unit that records the first image when it is determined that a relative distance between the host vehicle and a target vehicle behind the host vehicle is such that a license plate of the target vehicle falls within the first angle of view, and records the second image when it is determined that the relative distance is such that the license plate of the target vehicle does not fall within the first angle of view; An image recording device comprising:

2. The image recording device of claim 1, wherein the recording control unit determines whether the license plate of the target vehicle is far enough away to fit within the first angle of view, or whether the license plate of the target vehicle is close enough not to fit within the first angle of view, based on whether the license plate of the target vehicle can be recognized on the first image.

3. The image recording device of claim 1, wherein the recording control unit determines whether the license plate of the target vehicle is far enough away to fit within the first angle of view, or whether the license plate of the target vehicle is close enough not to fit within the first angle of view, based on whether the relative distance measured by a distance measuring unit that measures the relative distance between the vehicle itself and the target vehicle is greater than or equal to a predetermined distance.

4. the first imaging unit is an imaging unit provided to display the first image on an electronic rear-view mirror, 4. The image recording device according to claim 1, wherein the second image capturing section is an image capturing section provided for displaying the second image on a display section when the host vehicle is reversing.

Images