JP7740186B2 - Image recording device - Google Patents

Description

The present invention relates to an image recording device.

Patent Document 1 discloses a drive recorder that operates in a recording mode selected from the following: event recording mode, continuous recording mode, time lapse mode, and motion detection mode. With this drive recorder, time lapse mode or motion detection mode is selected while the vehicle is parked, and when motion detection mode is selected, video data is recorded if a moving object is detected from a change in the video.

Japanese Patent Application Laid-Open No. 2020-020553

When recording video captured at night, for example, it is preferable to capture the video so that it appears bright when displayed. To achieve this, the exposure time when capturing the video is lengthened. However, images captured with a long exposure time are prone to blurring, and when detecting moving objects in the captured video using image recognition, the presence of blurring can lead to a decrease in the accuracy of detecting moving objects in the captured image, leaving room for improvement.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide an image recording device that can suppress a decrease in the accuracy of detecting moving objects from captured images and record captured images that can be displayed appropriately.

To achieve the above object, a first aspect of the image recording device includes an imaging means for capturing images of the surroundings of a vehicle; a recording means for recording images captured by the imaging means on a recording medium when the device is in a first operating mode; an image recognition means for detecting moving objects in the images captured by the imaging means by recognizing them when the device is in a second operating mode; an exposure mode switching means for switching the exposure mode of the imaging means between a first exposure mode that adjusts the captured image so that it is suitable for display on an image display means and a second exposure mode that adjusts the captured image so that it is suitable for image recognition by the image recognition means; and a control means for controlling switching between the first operating mode and the second operating mode, such that when switching to the first operating mode, the exposure mode switching means switches to the first exposure mode, and when switching to the second operating mode, the exposure mode switching means switches to the second exposure mode, and when the image recognition means detects the moving object, the exposure mode switching means switches to the first operating mode and the first exposure mode.

In the image recording device of the first aspect, in the first operating mode, the recording means records the image captured by the imaging means on the recording medium, and in the second operating mode, the image recognition means detects a moving object in the image captured by the imaging means through image recognition. The control means switches between the first operating mode and the second operating mode. In this case, when the image recognition means detects a moving object in the captured image, the control means switches from the second operating mode to the first operating mode, thereby recording the image captured by the imaging means on the recording medium.

Here, the exposure mode switching means switches the exposure mode of the imaging means between a first exposure mode that adjusts the captured image so that it is suitable for display on the image display means, and a second exposure mode that adjusts the captured image so that it is suitable for image recognition by the image recognition means. The control means controls the exposure mode switching means to switch the exposure mode of the imaging means to the first exposure mode in the first operating mode, and to switch the exposure mode of the imaging means to the second exposure mode in the second operating mode.

As a result, when an image captured by the imaging means is recorded on a recording medium, the captured image can be adjusted to be suitable for display on the image display means. Furthermore, when an image captured by the imaging means is used for image recognition, the captured image is adjusted to be suitable for image recognition by the image recognition means.

The image recording device of the second aspect includes, in the first aspect, the control means controlling the device so that operation in the first operating mode is initiated when a start switch for vehicle operation is turned on, and operation in the second operating mode is initiated when the start switch is turned off.

In the second mode, the first operating mode is initiated when the start switch for running the vehicle is turned on, and the second operating mode is initiated when the start switch is turned off. In this case, in the first operating mode, the imaging means is switched to the first exposure mode, so that a captured image displayed at an appropriate brightness is recorded, and in the second operating mode, the imaging means is switched to the second exposure mode, so that moving objects can be detected with high accuracy.

The image recording device of the third aspect is the first or second aspect, and includes a configuration in which operation of the image recognition means is stopped in the first operating mode.

In the third aspect, in the first operating mode, the operation of the image recognition means is stopped, thereby suppressing the operation of the image recognition means.

According to the present invention, when an image captured by the imaging means is recorded on a recording medium, the captured image is adjusted to be suitable for display on the image display means, and when the image captured by the imaging means is used for image recognition, the captured image is adjusted to be suitable for image recognition by the image recognition means. This has the effect of suppressing a decrease in the accuracy of detecting moving objects from captured images and recording captured images that can be displayed appropriately.

1 is a block diagram showing a schematic configuration of a main part of a drive recorder according to an embodiment of the present invention; 3 is a flowchart showing an outline of the operation control of the drive recorder. 10 is a flowchart showing an outline of operation control during parking of a vehicle.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Figure 1 shows a block diagram of the general configuration of a drive recorder 10 as an image recording device according to this embodiment. The drive recorder 10 according to this embodiment is installed in a vehicle (not shown), captures images of the vehicle's surroundings, and records the captured images. Furthermore, when the drive recorder 10 detects a moving object, such as an approaching vehicle, in the captured image of a parked vehicle, it records the captured image on a recording medium.

As shown in FIG. 1, the drive recorder 10 includes a camera 12 as an imaging means and a controller 14 (ECU: Electronic Control Unit). The camera 12 is equipped with an imaging element (image sensor, not shown) such as a CCD image sensor or CMOS image sensor, and outputs image data from the imaging element at a preset time interval (frame rate), thereby outputting video data. For simplicity's sake, the image data and video data acquired by the camera 12 will be described below as captured images.

In the drive recorder 10, a camera 12 is installed inside or outside the vehicle. The drive recorder 10 may use one camera 12 or multiple cameras 12. The camera 12 is installed inside the windshield glass at the top front of the vehicle compartment to capture images in front of the vehicle. Note that the second and subsequent cameras 12 may be installed inside the rear glass at the rear of the vehicle compartment to capture images behind the vehicle, or may be installed on both sides of the vehicle body (on both sides in the vehicle width direction) to capture images to the sides of the vehicle.

The controller 14 is located in a housing (not shown), and the camera 12 is electrically connected to the controller 14. Note that the drive recorder 10 may have the camera 12 and controller 14 separate from each other, or may be an integrated type in which the camera 12 is located in the housing of the controller 14.

The controller 14 includes a microcomputer with a CPU, ROM, RAM, non-volatile storage, etc. connected via a bus, as well as the necessary electrical circuits (all not shown). In the controller 14, the CPU reads out programs stored in the ROM and storage, and executes them while expanding them into RAM, thereby realizing functions according to the programs.

The controller 14 stores an image recording program, an image recognition program, an exposure mode switching program, and an operation control program in its ROM and storage. The controller 14 also has a recording unit 16. This allows the controller 14 to include an image recording unit 20 as image recording means, an image recognition unit 22 as image recognition means, an exposure mode switching unit 24 as exposure mode switching means, and an operation control unit 26 as control means.

The recording unit 16 can use a portable memory card 30 (or USB memory) equipped with a flash memory such as an SD card, miniSD card, microSD card, or xD picture card as a storage medium. In this case, the recording unit 16 uses a writer (or reader/writer) for writing data to the memory card 30 when the memory card 30 is inserted. The recording unit 16 may also use a USB memory or an SSD (Solid State Drive). When an SSD or the like is used as the recording unit 16, an input/output interface is used so that captured images recorded on the recording unit 16 can be output to an external device.

The image recording unit 20 reads the images captured by the camera 12 and records (writes) the read images on the memory card 30. As a result, the images captured by the camera 12 are recorded as video on the memory card 30, and the captured images (video) recorded on the memory card 30 can be displayed on a monitor (display) or other display device. The drive recorder 10 may also be provided with a display such as an LCD (which may be electrically connected), allowing the captured images recorded on the memory card 30 to be displayed (played back) on the display.

The image recognition unit 22 reads the captured image captured by the camera 12 and performs image recognition on the read captured image to detect moving objects (mobile bodies) such as people in the captured image. This allows it to detect people or other objects approaching the vehicle while the vehicle is parked and not moving. Note that well-known methods can be applied to image recognition for detecting moving objects in the captured image, and detailed explanations will be omitted in this embodiment.

On the other hand, the camera 12 used in this embodiment adjusts the brightness of the captured image by adjusting the exposure time of the image sensor. The controller 14 sets the exposure mode of the camera 12 to a display mode and a recognition mode. The exposure mode switching unit 24 switches the exposure mode of the camera 12 between the display mode and the recognition mode.

Display mode is the first exposure mode, and in display mode, the exposure time is adjusted so that the captured image has appropriate brightness when displayed on the display. In display mode, the exposure time is adjusted so that the subject in the captured image is visible even at night, when the image captured by the camera 12 is dark.

Recognition mode is the second exposure mode, and in recognition mode, when image recognition is performed using a captured image, the exposure time is adjusted so that moving objects (subjects) in the captured image can be identified. In recognition mode, the exposure time is adjusted so that the subject in the captured image is visible (without being too bright) even at night, when the image captured by camera 12 is dark. As a result, in recognition mode, the exposure time is adjusted so that the captured image (subject in the captured image) does not become too bright and its contours become unclear, and is adjusted to be shorter than in display mode. Note that in both display mode and recognition mode, the exposure time is adjusted to prevent the image captured by camera 12 from becoming too bright during the day due to backlighting, etc.

The operation control unit 26 is connected to an IG switch (ignition switch) 32 that serves as a start switch provided on the vehicle. The operation control unit 26 detects the on/off (ON/OFF) operation of the IG switch 32 and switches the operation mode of the drive recorder 10 in response to the on/off operation of the IG switch 32. Note that if the vehicle has an engine as a driving source, the IG switch 32 is used, but if the vehicle has an electric motor as a driving source (such as an electric vehicle), a power switch is used as the start switch.

When the IG switch 32 is turned on, the operation control unit 26 switches the operation of the drive recorder 10 to image recording mode, and when the IG switch 32 is turned off, the operation control unit 26 switches the operation of the drive recorder 10 to monitoring mode. The operation control unit 26 also controls the exposure mode switching unit 24 so that the exposure mode of the camera 12 is switched to display mode in image recording mode, and the exposure mode of the camera 12 is switched to recognition mode in monitoring mode.

Next, as the operation of this embodiment, the operation of the drive recorder 10 will be described.
FIG. 2 is a flowchart showing an outline of the operation mode switching process executed by the controller 14, and FIG. 3 is a flowchart showing an outline of the process in the image recognition mode.

The drive recorder 10 operates regardless of whether the IG switch 32 is on or off, and the controller 14 executes the process shown in Figure 2 at predetermined time intervals to switch operating modes and perform image recording processing, and executes the process shown in Figure 3 to perform monitoring processing and image recording processing during monitoring processing.

In the first step 100 of the flowchart in Figure 2, the controller 14 checks whether the IG switch 32 is on. If the IG switch 32 is on to drive the vehicle, the controller 14 makes a positive determination in step 100 and proceeds to step 102.

In step 102, the controller 14 sets the operating mode to image recording mode. At the same time, in step 104, the controller 14 controls the exposure mode switching unit 24 to switch the exposure mode of the camera 12 to display mode. Then, in step 106, the controller 14 reads images captured by the camera 12 and records the read images sequentially on the memory card 30.

As a result, the drive recorder 10 continues to operate in image recording mode until the IG switch 32 is turned off to stop driving and park the vehicle, and images (video) captured by the camera 12 while the vehicle is driving are recorded on the memory card. Furthermore, because the exposure mode of the camera 12 in the drive recorder 10 is set to display mode, high-quality images are recorded on the memory card 30 that allow each subject in the captured image to be easily recognized when displayed on a display or the like.

On the other hand, when the vehicle has finished driving and is parked, the IG switch 32 is turned off. When the IG switch 32 is turned off, the controller 14 makes a negative determination in step 100 and proceeds to step 108. In step 108, the controller 14 sets (switches) the operating mode to monitoring mode. As a result, the drive recorder 10 ends the image recording mode and transitions to monitoring mode.

The controller 14 begins executing the flowchart of FIG. 3 by proceeding to step 108. In the first step 110 of this flowchart, the controller 14 switches the exposure mode of the camera 12 to the recognition mode, and then in step 112 begins image recognition. In image recognition, the controller 14 reads in the image captured by the camera 12 and performs image recognition on the read-in image to detect the presence or absence of a moving object.

This allows the drive recorder 10 to detect people or other objects approaching the vehicle while it is parked. When the IG switch 32 is turned on, the controller 14 ends monitoring mode and transitions to image recording mode (see Figure 2).

When a person or other object approaches the vehicle, the appearance of a moving object in the captured image is detected by performing image recognition on the image captured by camera 12. In step 114, controller 14 checks whether a moving object has been detected by image recognition, and if a moving object is detected, controller 14 makes a positive determination in step 114 and proceeds to step 116.

In step 116, the controller 14 stops image recognition and stops operation in monitoring mode. In the next step 118, the controller 14 changes the operating mode to image recording mode.

At the same time, in step 120, the controller 14 switches the exposure mode of the camera 12 to the display mode (corresponding to step 104 in Figure 2), and in step 122, starts recording images captured by the camera 12 to the memory card 30 (corresponding to step 106 in Figure 2). As a result, in the drive recorder 10, images captured by the camera 12 that include moving objects (such as a person approaching the vehicle) are recorded to the memory card 30.

The controller 14 then checks in step 124 whether to stop recording the captured image, and when the preset stop timing is reached, a positive determination is made in step 124, and the process proceeds to step 126 to stop image recording. Note that the timing for stopping image recording can be when a preset time has elapsed (for example, several minutes to several tens of minutes), when the IG switch 32 is turned on, or the like.

As a result, the drive recorder 10 stops recording images captured by the camera 12 while the vehicle is parked, and the controller 14 returns to the flowchart in Figure 2, thereby starting operation in the operating mode (image recording mode or monitoring mode) corresponding to the on/off state of the IG switch 32.

In this way, the drive recorder 10 switches the exposure mode of the camera 12 between a display mode, in which the captured image is adjusted to be suitable for display on the image display means, and a recognition mode, in which the captured image is adjusted to be suitable for image recognition. Furthermore, the display mode is applied to the exposure mode of the camera 12 in the image recording mode, and the recognition mode is applied in the monitoring mode.

As a result, when images captured by camera 12 are recorded on memory card 30, they are adjusted to be suitable for display on the display. Furthermore, when images captured by camera 12 are used for image recognition, the captured images are adjusted to be suitable for image recognition. Therefore, the drive recorder 10 can prevent a decrease in the accuracy of detecting moving objects from images captured by camera 12, and can record images captured by camera 12 so that they can be displayed appropriately.

In addition, when the IG switch 32 for vehicle driving is turned on in the drive recorder 10, the exposure mode of the camera 12 is set to display mode and operation in image recording mode begins. When the IG switch 32 is turned off, the exposure mode of the camera 12 is set to recognition mode and operation in monitoring mode for detecting moving objects begins. As a result, the drive recorder 10 records captured images that can be displayed at appropriate brightness on the memory card 30 while the vehicle is driving, and can accurately detect moving objects moving around the vehicle, such as those approaching the vehicle while it is parked.

Furthermore, in the drive recorder 10, the controller 14 stops image recognition in image recording mode, which reduces the processing load on the controller 14 and reduces product costs compared to using functional components with high processing capabilities.

In the embodiment described above, when the IG switch 32 is turned on, the exposure mode is switched to the display mode and operation in the image recording mode is initiated, and when the IG switch 32 is turned off, the exposure mode is switched to the recognition mode and operation in the monitoring mode is initiated. However, when applying the second operating mode, the image recording device may apply the first exposure mode as the exposure mode during the day when the surroundings of the vehicle are relatively bright, and the second exposure mode as the exposure mode during the night when the surroundings of the vehicle are dark.

In other words, the control means may control the exposure mode switching means to switch to the second exposure mode when operating in the second operating mode at night. In this case, an illuminance sensor (sunlight sensor) or the like may be used to detect the brightness around the vehicle while operating in the second operating mode, and the exposure mode of the imaging means may be switched to the second exposure mode when the brightness around the vehicle becomes a predetermined level or less. This allows for effective exposure mode switching and accurate image recognition.

Furthermore, in this embodiment, the image recognition unit 22 detects a moving object from the image captured by the camera 12. However, the image recording device may also include vibration detection means or acceleration detection means for detecting vibrations, etc. applied to the vehicle body, and if a moving object is detected by the image recognition means or vibrations, etc. of the vehicle body are detected by the acceleration detection means, etc. while operating in the second operating mode, the device may switch to the first operating mode and record the image captured by the imaging means on the recording medium.

10. Drive recorder (image recording device)
12 Camera (imaging means)
14 Controller 20 Image recording unit (image recording means)
22 Image recognition unit (image recognition means)
24 Exposure mode switching unit (exposure mode switching means)
26 Operation control means (control means)
30 Memory card (recording medium)
32 IG switch (start switch)

Claims (3)

imaging means for imaging the surroundings of the vehicle;
a recording means for recording an image captured by the imaging means on a recording medium when the camera is in a first operation mode;
an image recognition unit that recognizes a moving object in an image captured by the imaging unit when the second operation mode is selected;
an exposure mode switching means for switching an exposure mode when capturing an image by the image capturing means between a first exposure mode in which the captured image is adjusted to a brightness suitable for display on the image display means and a second exposure mode in which the captured image is adjusted to a brightness suitable for image recognition by the image recognition means;
a control means for controlling the exposure mode switching means so that, when controlling switching between the first operation mode and the second operation mode, the exposure mode is switched to the first exposure mode when switching to the first operation mode, the exposure mode is switched to the second exposure mode when switching to the second operation mode , and the exposure mode is switched to the first exposure mode when the moving object is recognized by the image recognition means in the second operation mode and the operation mode is switched to the first operation mode;
An image recording device comprising: The image recording device of claim 1, wherein the control means controls the vehicle so that operation in the first operating mode is initiated when a start switch for vehicle operation is turned on, and operation in the second operating mode is initiated when the start switch is turned off. 3. The image recording device according to claim 1, wherein the image recognition means starts operating when the first operating mode is switched to the second operating mode, and stops operating prior to switching from the second operating mode to the first operating mode.