Video recording device

Abstract

To provide a technique for suppressing power consumption and then easily recording in an appropriate manner a behavior of a suspicious person near a vehicle.SOLUTION: In a video recording device 10, a sound acquisition section 40 acquires sounds inputted to a microphone installed on a vehicle being parked. On the basis of the acquired sounds, an estimation section 42 estimates whether a target approaches the vehicle. In a case where it is estimated that the target approaches the vehicle, a video recording control section 32 activates a camera installed on the vehicle and starts recording a video in a direction in which the acquired sounds come.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an in-vehicle video recording device. [Background technology]

[0002] In recent years, the installation of drive recorders in vehicles has been increasing. Drive recorders have cameras that can record the outside and inside of the vehicle, and can record while driving, when an accident occurs, and when the vehicle is parked. When recording while the vehicle is parked, it is common to stop the camera operation while the vehicle is on standby to reduce power consumption, and to start the camera when a sensor detects something and starts recording.

[0003] For example, Patent Document 1 discloses an information recording device that acquires image and audio information from a camera and a microphone for a first period of time from when a sensor including a vibration sensor detects that an abnormality has occurred in the vehicle, and stores the information in a second RAM. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-143324 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventor has recognized that there is a demand for recording the behavior of a suspicious person even when the vibration applied to a vehicle by the suspicious person is smaller than the threshold value of a vibration sensor and cannot be detected, and that there is also a demand for recording the behavior of the suspicious person before the vibration is applied to the vehicle.

[0006] The present invention has been made in consideration of these circumstances, and its purpose is to provide a technology that makes it easy to appropriately record the behavior of suspicious people near a vehicle while reducing power consumption. [Means for solving the problem]

[0007] In order to solve the above problems, a video recording device of one embodiment of the present invention includes a sound acquisition unit that acquires sound input to a microphone installed in a parked vehicle, an estimation unit that estimates whether or not a target is approaching the vehicle based on the acquired sound, and a recording control unit that, if it is estimated that a target is approaching the vehicle, activates a camera installed in the vehicle and begins recording video from the direction from which the acquired sound is coming.

[0008] Any combination of the above components, and any transformation of the present invention into a method, device, system, recording medium, computer program, etc., are also effective as aspects of the present invention. Effect of the Invention

[0009] According to the present invention, it is possible to provide a technology that can easily and appropriately record the behavior of suspicious people near a vehicle while suppressing power consumption. [Brief description of the drawings]

[0010] [Figure 1] 1 is a top view showing a schematic diagram of a vehicle in which a video recording device according to a first embodiment is installed. [Diagram 2] FIG. 2 is a block diagram showing the configuration of the video recording device of FIG. 1. [Diagram 3] 3 is a flowchart showing a process in a parking monitoring mode of the video recording device of FIG. 2. [Figure 4] FIG. 11 is a top view that shows a schematic diagram of a vehicle in which a video recording device according to a second embodiment is installed. [Diagram 5] FIG. 13 is a top view showing a vehicle in which a video recording device according to a fourth modified example is installed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (First embodiment) 1 is a top view showing a vehicle 1 equipped with a video recording device 10 according to a first embodiment. The video recording device 10 is a drive recorder installed in the passenger compartment of the vehicle 1, and operates using power from a battery of the vehicle 1, for example.

[0012] 1, the video recording device 10 includes a first camera 12a, a second camera 12b, a third camera 12c, a fourth camera 12d, a first microphone 20a, and a second microphone 20b. Hereinafter, the first camera 12a, the second camera 12b, the third camera 12c, and the fourth camera 12d will be collectively referred to as the camera 12 as appropriate. The first microphone 20a and the second microphone 20b will be collectively referred to as the microphone 20 as appropriate.

[0013] The first camera 12a is installed in a position where it can capture an image of the front of the vehicle 1. The second camera 12b is installed in a position where it can capture an image of the rear of the vehicle 1. The third camera 12c is installed in a position where it can capture an image of the left side of the vehicle 1. The fourth camera 12d is installed in a position where it can capture an image of the right side of the vehicle 1.

[0014] The first microphone 20a is a directional microphone and is installed at a position where it can mainly pick up sounds near the left seat. The first microphone 20a can also pick up sounds near the left door of the vehicle 1 and sounds outside the door. An example of a rough sound pickup range Ra of the first microphone 20a is indicated by a dashed line.

[0015] The second microphone 20b is a directional microphone, and is installed at a position where it can mainly pick up sounds near the right seat. The second microphone 20b can also pick up sounds near the right door of the vehicle 1 and outside the door. An example of a rough sound pickup range Rb of the second microphone 20b is shown by a dashed line. The microphone 20 is provided in a housing that includes the first camera 12a and a microcomputer, which will be described later.

[0016] The video recording device 10 operates in a normal mode while the vehicle 1 is running, captures surrounding images with the camera 12, captures sounds inside and outside the vehicle with the microphone 20, and records the captured images and the captured sounds. A known operation can be adopted as the operation in the normal mode. The video recording device 10 also operates in a low-power parking monitoring mode while the vehicle 1 is parked, stops the operation of the camera 12, etc., and monitors whether an object is approaching the vehicle 1 by detecting sounds with the microphone 20. When it is estimated that an object is approaching, the video recording device 10 starts the camera 12, etc., captures images in the direction from which the sound is coming, and records the captured images. This makes it possible to suppress power consumption, and to easily detect the approach of an object before vibrations are applied to the vehicle body, and to start recording the images. Here, the "object" of the sound detected by the microphone 20 in the parking monitoring mode is mainly a "person", and it is assumed that the person is performing suspicious behavior that may cause some kind of harm to the vehicle. Hereinafter, the object of the sound detected by the microphone 20 will be described as a "person" or a "suspicious person".

[0017] Fig. 2 is a block diagram showing the configuration of the video recording device 10 of Fig. 1. As shown in Fig. 2, the video recording device 10 includes four cameras 12, a first processing unit 14, a first storage unit 16, two microphones 20, a vibration sensor 22, a second processing unit 24, and a second storage unit 26.

[0018] Each camera 12 supplies captured image data to a first processing unit 14. The first processing unit 14 is configured with, for example, a main microcomputer. The first processing unit 14 controls each camera 12 and causes the first storage unit 16 to record the video images supplied from each camera 12.

[0019] The first storage unit 16 includes, for example, an SD card, and records the images captured by each camera 12.

[0020] The first processing unit 14 has a video acquisition unit 30 and a recording control unit 32. The multiple functional blocks of the first processing unit 14 can be configured in hardware with circuit blocks, memory, and other LSIs, and are realized in software by a CPU executing a program loaded in a memory, etc. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms by hardware alone, software alone, or a combination thereof, and are not limited to any one of them.

[0021] In the normal mode, the recording control unit 32 controls each camera 12, the video acquisition unit 30, and the first storage unit 16, and causes the video captured by each camera 12 to be recorded in the first storage unit 16. Specifically, in the normal mode, the video acquisition unit 30 acquires the video captured by each camera 12, and supplies data of the acquired video to the first storage unit 16.

[0022] Each microphone 20 supplies input sound data to a second processing unit 24 . The vibration sensor 22 detects vibrations of the body of the vehicle 1, and supplies detection data including information on the magnitude of the detected vibrations to the second processing unit 24. The vibration sensor 22 is optional.

[0023] The second processing unit 24 is configured with, for example, a sub-microcomputer. In the parking monitoring mode, the second processing unit 24 detects the approach of a person to the vehicle 1 based on the sound input to each microphone 20 and the vibration detected by the vibration sensor 22.

[0024] The second processing unit 24 has a sound acquisition unit 40, an estimation unit 42, and a monitoring control unit 44. The multiple functional blocks of the second processing unit 24 can be configured in hardware with circuit blocks, memory, and other LSIs, and are realized in software by a CPU executing a program loaded in a memory, etc. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms by hardware alone, software alone, or a combination thereof, and are not limited to any one of them.

[0025] The monitoring control unit 44 detects whether the vehicle 1 is parked or not parked. Known techniques can be used to detect parking and the end of parking. For example, the monitoring control unit 44 receives information indicating the state of the start switch of the vehicle 1, and determines that the vehicle 1 is parked when the start switch is turned off, and determines that the vehicle 1 is not parked when the start switch is turned on. The start switch is a switch that is operated to start or stop the driving source for running the vehicle 1, and is called an ignition switch or power switch.

[0026] When it is detected that the vehicle 1 is parked, the monitoring control unit 44 ends the normal mode, starts the parking monitoring mode, and stops the operation of the camera 12, the first processing unit 14, and the first storage unit 16. The power consumption of each component that has stopped operating becomes substantially zero. The second processing unit 24 can operate with lower power consumption than the power consumption of the camera 12, the first processing unit 14, and the first storage unit 16. Therefore, the power consumption in the parking monitoring mode can be reduced.

[0027] When it is detected that the vehicle 1 is not parked, the monitoring control unit 44 ends the parking monitoring mode, starts the normal mode, activates the first processing unit 14, and supplies a shooting instruction for the normal mode to the first processing unit 14. When the first processing unit 14 is activated, the recording control unit 32 starts recording video as described above in accordance with the received shooting instruction. In the normal mode, the sound acquisition unit 40 acquires sounds input to each microphone 20, and supplies data of the acquired sounds to the recording control unit 32. The recording control unit 32 also records the sound data in the first storage unit 16.

[0028] In the parking monitoring mode, the following process is executed.

[0029] The sound acquisition unit 40 periodically acquires sounds input to each microphone 20, and supplies information about the acquired sounds to the estimation unit .

[0030] The estimation unit 42 periodically estimates whether or not a person is approaching the vehicle 1 based on the sound acquired by the sound acquisition unit 40. When a predetermined condition related to the acquired sound is satisfied, the estimation unit 42 estimates that a person is approaching the vehicle 1. The predetermined condition is, for example, that the volume of the acquired sound is equal to or greater than a threshold value and that a characteristic related to the frequency of the acquired sound has changed.

[0031] If the volume of the acquired sound is equal to or greater than a threshold value and the characteristics related to the frequency of the acquired sound change in either the sound acquired from the first microphone 20a or the sound acquired from the second microphone 20b, the estimation unit 42 estimates that a person has approached the vehicle 1 and notifies the monitoring control unit 44 of the estimation result. In this case, the estimation unit 42 identifies the arrival direction of the sound and also notifies the arrival direction of the sound to the monitoring control unit 44. If a predetermined condition is satisfied for the sound acquired from the left first microphone 20a, the estimation unit 42 identifies the arrival direction of the sound as the left side, and if a predetermined condition is satisfied for the sound acquired from the right second microphone 20b, the estimation unit 42 identifies the arrival direction of the sound as the right side.

[0032] If the volume of the sound acquired from the first microphone 20a and the sound acquired from the second microphone 20b is less than a threshold value or if the frequency characteristics of the acquired sound have not changed, the estimation unit 42 estimates that no person is approaching the vehicle 1 and stores the frequency characteristics of the sound in the second memory unit 26.

[0033] The second storage unit 26 includes a memory such as a RAM (Random Access Memory) and stores features related to the frequencies of the sounds acquired from the first microphone 20a and the second microphone 20b. The second storage unit 26 is updated as needed with the latest features related to the frequencies of the sounds.

[0034] Specifically, the estimation unit 42 executes the following process for each of the sound acquired from the first microphone 20a and the sound acquired from the second microphone 20b. The estimation unit 42 reads out the feature related to the frequency of the sound acquired at the previous processing timing (hereinafter also referred to as the second feature) from the second storage unit 26. If the feature related to the frequency of the sound acquired at the current processing timing (hereinafter also referred to as the first feature) is different from the read second feature, the estimation unit 42 determines that the feature related to the frequency of the sound has changed. If the first feature is the same as the read second feature, the estimation unit 42 determines that the feature related to the frequency of the sound has not changed. If the difference between the first feature and the second feature is within a predetermined range, the estimation unit 42 determines that the first feature and the second feature are the same. The threshold value and the predetermined range of the volume can be appropriately determined by an experiment. The threshold value and the predetermined range of the volume may be set by the user. In addition, in the above description, the change is determined based on the first feature and the second feature from the previous time, but the change may also be determined by referring to more information by storing the feature from the time before last or even further back in the second memory unit 26.

[0035] The feature related to the frequency of the sound may be, for example, the length of one period of the waveform of the sound. The feature related to the frequency of the sound may be the frequency of a frequency component contained in the sound that is equal to or greater than a threshold value. This frequency may be multiple. This frequency may be derived by applying an FFT (Fast Fourier Transform) to the sound signal. By using such simple features, the computational load can be reduced, and power consumption can also be reduced.

[0036] The frequency of sound acquisition by the sound acquisition unit 40 and the frequency of estimation by the estimation unit 42 may be, for example, once every few seconds, and can be appropriately determined through experiments.

[0037] The estimation unit 42 may estimate whether or not a person has approached the vehicle 1 based on the acquired sound, using a trained model such as a neural network.

[0038] When the estimation unit 42 estimates that a person has approached the vehicle 1, the monitoring control unit 44 activates the first processing unit 14 and supplies the first processing unit 14 with an instruction to capture an image including the direction from which the sound is coming.

[0039] When the first processing unit 14 is started, the recording control unit 32 starts the camera 12 in the direction from which the sound comes according to the received shooting instruction, and starts recording the video in the direction from which the sound comes. Specifically, the video acquisition unit 30 acquires the video in the direction from which the sound comes from the left or right, which is captured for a certain period of time by the activated third camera 12c or fourth camera 12d, and supplies the acquired video data to the first storage unit 16. The first storage unit 16 records the video in the direction from which the sound comes for a certain period of time. The first storage unit 16 may also record the sound input to the microphone 20. The certain period of time may be within a range of, for example, several seconds to about one minute, and can be appropriately determined by experiment. The certain period of time may be set by the user.

[0040] For example, if the sound is coming from the right side, there is a possibility that a person is approaching the vehicle 1 along the path p1 indicated by the arrow in Fig. 1. In this case, the video captured by the fourth camera 12d is recorded.

[0041] When the fixed period of photographing and video recording has ended, the monitoring control unit 44 stops the operation of the camera 12, the first processing unit 14, and the first storage unit 16, and returns to the processing already described in the parking monitoring mode.

[0042] In the embodiment, the recording control unit 32 is described as not activating cameras 12 other than the camera 12 in the direction from which the sound is coming. This can reduce power consumption. Since the recording control unit 32 does not record images other than images in the direction from which the sound is coming, the amount of recorded data can also be reduced.

[0043] In addition, even if the monitoring control unit 44 estimates that no person is approaching the vehicle 1, it determines whether the magnitude of vibration generated in the body of the vehicle 1 exceeds the vibration threshold based on the detection data supplied from the vibration sensor 22. Even if the magnitude of vibration exceeds the vibration threshold, the monitoring control unit 44 starts the first processing unit 14 and supplies a shooting instruction to the first processing unit 14. The vibration threshold can be appropriately determined by experiment. The vibration threshold may be set by the user. When the first processing unit 14 starts, the recording control unit 32 starts the four cameras 12 in accordance with the shooting instruction and starts recording images in four directions. When the shooting and recording of images for a certain period of time are completed, the monitoring control unit 44 stops the operation of the cameras 12, the first processing unit 14, and the first storage unit 16, and returns to the processing described above in the parking monitoring mode. By using the vibration sensor 22 in combination, it is possible to record images even if a suspicious person approaches the vehicle 1 without making a sound.

[0044] Fig. 3 is a flowchart showing the processing of the parking monitoring mode of the video recording device 10 of Fig. 2. The processing of Fig. 3 is periodically executed when it is detected that the vehicle 1 has been parked. This processing is executed for each of the sounds input to the two microphones 20.

[0045] The sound acquisition unit 40 acquires sound input to the microphone 20 (S10), and if the volume is not greater than or equal to the threshold value (N in S12), the second memory unit 26 stores the frequency-related characteristics of the sound acquired this time (S16), and the processing ends.

[0046] If the volume is equal to or greater than the threshold value in S12 (Y in S12), and if the characteristics related to the frequency of the acquired sound are the same as the characteristics related to the frequency of the sound acquired previously (N in S14), the process proceeds to S16. If the characteristics related to the frequency of the acquired sound are different from the characteristics related to the frequency of the sound acquired previously (Y in S14), the recording control unit 32 starts up the camera 12 in the direction from which the acquired sound comes, records video for a certain period of time in the direction from which the acquired sound comes (S18), and ends the process.

[0047] According to the embodiment, the approach of a person can be detected before vibrations are applied to the body of the vehicle 1, making it easier to start recording video. Even if the vibration sensor 22 cannot detect vibrations applied to the body, it is easier to start recording video. Even if a suspicious person does not touch the vehicle 1, recording can be started by making a suspicious movement and sound near the door of the vehicle 1, so it is possible to record the actions of the suspicious person before touching the vehicle 1, the direction from which the suspicious person came, and the suspicious person's advance reconnaissance. Therefore, it is easier to properly record the actions of a suspicious person near the vehicle 1.

[0048] In addition, power consumption can be reduced compared to a configuration in which the camera is always operating while the vehicle is parked and recording is performed, or a configuration in which a motion sensor is used separately to detect human movement. Since video in the direction of the sound is recorded, power consumption and the amount of recorded data can be reduced compared to recording video in all possible directions. The approach of a person can be detected using the existing microphone 20 of the video recording device 10, without the need to install new motion sensors or radio wave sensors for detecting human movement in each location and direction of the vehicle 1. This can reduce costs and the complexity of installation work such as wiring.

[0049] Furthermore, the video recording device 10 can be configured by updating the software without changing the system configuration of the existing drive recorder, so it can be configured inexpensively. Also, it can be combined with the vibration sensor of the existing drive recorder, so by operating both functions, sufficient operation can be expected even in situations where it is difficult to detect sound.

[0050] The estimation unit 42 may set the above-mentioned predetermined condition, which is a condition for estimating that a person has approached the vehicle 1, according to the surrounding conditions of the vehicle 1. For example, when the surrounding conditions of the vehicle 1 are conditions in which the noise is relatively loud, i.e., conditions in which erroneous detection is likely to occur, the estimation unit 42 may set the predetermined condition so that it is less likely to be estimated that a person has approached the vehicle 1, compared to when the noise is relatively quiet. Setting the predetermined condition so that it is less likely to be estimated that a person has approached the vehicle 1 may include, for example, setting the threshold value of the sound volume higher than the reference value and setting the predetermined range narrower than the reference range. This makes it possible to suppress erroneous determinations and more accurately estimate that a person has approached the vehicle 1, according to the surrounding conditions of the vehicle 1.

[0051] For example, the estimation unit 42 may determine that the surrounding conditions of the vehicle 1 are conditions in which noise is relatively low when the current time is within a specified time period including late night and early morning, and may determine that the surrounding conditions of the vehicle 1 are conditions in which noise is relatively high when the current time is outside the specified time period.

[0052] For example, when the volume of the sound acquired from the first microphone 20a and the sound acquired from the second microphone 20b is equal to or greater than a threshold value continuously for a predetermined period of time, the estimation unit 42 may determine that the surrounding conditions of the vehicle 1 are conditions in which the noise is relatively loud. In bad weather such as heavy rain or strong winds, or in a situation where there is a lot of pedestrian traffic near the vehicle 1, it is expected that the sounds acquired by each of the two microphones 20 will be continuously loud. The predetermined period of time can be appropriately determined through experiments.

[0053] The estimation unit 42 may set a predetermined condition so that, when an obstacle such as a wall that prevents a person from approaching the vehicle 1 is present on the left or right side of the vehicle 1, the sound acquired from the microphone 20 in the direction in which the obstacle is present is excluded from the determination. For example, when a wall is present immediately adjacent to the left side of the vehicle 1, the estimation unit 42 estimates that a person has approached the vehicle 1 when the volume of the sound acquired from the second microphone 20b on the right side is equal to or greater than a threshold value and the characteristics related to the frequency of the sound have changed. In this case, since it is unlikely that a suspicious person approaches from the direction in which the obstacle is present, erroneous determination can be suppressed by excluding the sound in the direction in which the obstacle is present and determining the approach of a person. The estimation unit 42 may identify the presence of an obstacle and the direction of the obstacle by known image recognition or the like based on the image of the camera 12 when the vehicle 1 is parked.

[0054] The user may operate an external terminal such as a smartphone, and the estimation unit 42 may change the predetermined condition in response to a change instruction wirelessly transmitted from the external terminal in response to the user operation. This allows the user to adjust the predetermined condition in accordance with the surrounding situation of the vehicle 1.

[0055] Furthermore, when it is estimated that a person has approached the vehicle 1 more than a predetermined frequency, the estimation unit 42 may stop the estimation for a certain period of time. The predetermined frequency can be appropriately determined through experiments. When an approach is detected more frequently than the predetermined frequency, there is a high possibility that the erroneous determination is due to the surrounding conditions being inappropriate. In this case, only abnormality detection by the vibration sensor 22 is performed.

[0056] (Second embodiment) The second embodiment differs from the first embodiment in that a microphone array is formed using a plurality of omnidirectional microphones to identify the direction from which a sound comes. The following mainly describes the differences from the first embodiment.

[0057] Fig. 4 is a top view showing a vehicle 1 in which a video recording device 10A according to the second embodiment is installed. The video recording device 10A further includes a third microphone 20c and a fourth microphone 20d in addition to the configuration of the video recording device 10 shown in Fig. 1. Hereinafter, the first microphone 20a, the second microphone 20b, the third microphone 20c, and the fourth microphone 20d will be collectively referred to as microphones 20 as appropriate.

[0058] Each of the four microphones 20 is an omnidirectional microphone. The four microphones 20 form a microphone array. The first microphone 20a is installed on the front left side of the vehicle interior. The second microphone 20b is installed on the front right side of the vehicle interior. The third microphone 20c is installed on the rear left side of the vehicle interior. The fourth microphone 20d is installed on the rear right side of the vehicle interior.

[0059] The third microphone 20c and the fourth microphone 20d are provided, for example, in a housing including the second camera 12b. The third microphone 20c and the fourth microphone 20d also supply input sound data to the second processing unit 24. The number of microphones 20 is not limited to "4" and can be determined appropriately depending on the required performance of the microphone array.

[0060] The sound acquisition unit 40 periodically acquires sounds input to each of the four microphones 20, and supplies information about the acquired sounds to the estimation unit .

[0061] When the estimation unit 42 estimates that a person has approached the vehicle 1 based on the multiple sounds acquired by the sound acquisition unit 40, the estimation unit 42 identifies the direction from which the sound is coming based on the multiple sounds acquired. To identify the direction from which the sound is coming, a known technology for identifying the direction of a sound source using beamforming using a microphone array or the like may be used.

[0062] The estimation unit 42 may estimate the position and moving direction of the sound source of the acquired sound based on the acquired sounds. In this case, the estimation unit 42 estimates that a person has approached the vehicle 1 when the sound source moves toward the vehicle 1, the volume of the acquired sound is equal to or greater than a threshold, and the characteristics related to the frequency of the acquired sound change. This makes it possible to more accurately estimate that a person has approached the vehicle 1, suppress the recording of unnecessary video, and further reduce power consumption. For example, when it is estimated that the sound source is moving along the path p2 or path p3 indicated by the arrow in FIG. 4, it is not estimated that a person has approached the vehicle 1 because the sound source is not moving toward the vehicle 1. In this case, it is highly likely that a passerby simply walked past the vehicle 1, so recording is considered unnecessary.

[0063] According to the second embodiment, a microphone array can be configured with multiple microphones 20 on the front side of the vehicle 1 and multiple microphones 20 on the rear side, so that the sound arrival direction, the position of the sound source, and the moving direction of the sound source can be estimated with higher accuracy. In addition, as shown in Fig. 4, the microphones arranged in the front and rear can be widely spaced, making it easier to analyze the time difference when the sound arrives and accurately estimating whether the sound is coming from the front or rear. Correspondingly, it is also possible to suitably select and record the images from the first camera 12a that captures the front and the second camera 12b that captures the rear.

[0064] In addition, the housing having the first camera 12a arranged at the front of the vehicle interior is used as the main housing, which houses the first processing unit 14 and the second processing unit 24, and the sub-housing having the second camera 12b arranged at the rear of the vehicle interior is used as the sub-housing. The communication line connecting the main housing arranged at the front of the vehicle interior may be used for both communication of video data for recording and communication of audio data for the parking monitoring mode. When recording rearward video data, this communication line transmits video data required for recording, which is captured by the second camera 12b. When detecting a suspicious person in the parking monitoring mode, the data to be transmitted is switched, and this communication line transmits audio data input to the third microphone 20c and the fourth microphone 20d. This eliminates the need to increase the number of communication lines.

[0065] The present invention has been described above based on the embodiment. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each treatment process, and that such modifications are also within the scope of the present invention.

[0066] (First Modification) In the first and second embodiments, video recording begins when it is estimated that a person is approaching vehicle 1, but video recording may also begin after the camera 12 has gone through a standby state depending on whether the person has left the approaching state.

[0067] When the estimation unit 42 estimates that a person has approached the vehicle 1, the monitoring control unit 44 activates the first processing unit 14 and supplies the first processing unit 14 with a standby instruction including the direction from which the sound is coming.

[0068] When the first processing unit 14 is started, the recording control unit 32 starts the camera 12 in the direction from which the sound comes in accordance with the received standby instruction, and waits in a standby state. In the standby state, shooting does not start.

[0069] When the estimation unit 42 estimates that a person is approaching the vehicle 1, the estimation unit 42 periodically estimates, based on the sound acquired by the sound acquisition unit 40, whether or not the person is moving away from the vehicle 1.

[0070] If the estimation unit 42 does not estimate that a person is leaving the vehicle 1 within a predetermined waiting period after sending the standby instruction, or if the magnitude of the vibration detected by the vibration sensor 22 exceeds the vibration threshold value, the monitoring control unit 44 supplies a shooting instruction to the first processing unit 14. The waiting period can be appropriately determined through experiments. In accordance with the received shooting instruction, the recording control unit 32 causes the activated third camera 12c or fourth camera 12d to start shooting and start recording the video in the direction from which the sound is coming. Since the camera 12 is already activated, it can start shooting and recording immediately in response to the shooting instruction.

[0071] On the other hand, if the estimation unit 42 estimates that a person will leave the vehicle 1 within the standby period after sending the standby instruction and the magnitude of the vibration detected by the vibration sensor 22 does not exceed the vibration threshold value, the monitoring control unit 44 stops the operation of the camera 12, the first processing unit 14, and the first memory unit 16, and returns to the processing of the parking monitoring mode described above. According to the first modified example, it is possible to suppress unnecessary recording.

[0072] (Second Modification) In the first and second embodiments, four cameras 12 are provided, but one camera 12 may be provided. In this case, the camera 12 may be a camera with a fisheye lens capable of capturing an image of the surroundings of the vehicle 1 in 360 degrees, or may be a camera that can rotate 360 ​​degrees.

[0073] The recording control unit 32 starts the camera 12 according to the received shooting instruction, and starts recording the video in the direction from which the sound is coming. In the case of the camera 12 having a fisheye lens, the camera 12 shoots the video within a predetermined range including the direction from which the sound is coming. The camera 12 may be controlled to maintain a high resolution of the video within the predetermined range compared to the case of shooting the surroundings in 360 degrees. In the case of the camera 12 that can rotate 360 ​​degrees, the camera 12 rotates to face the direction from which the sound is coming, and shoots the video within a predetermined range including the direction from which the sound is coming. This modification improves the degree of freedom of the configuration of the video recording device 10.

[0074] (Third Modification) In the first embodiment, the video recording device 10 may further include a third microphone 20c installed at a position capable of picking up sounds mainly from the front of the vehicle 1. The third microphone 20c is also a directional microphone. When it is estimated that a person is approaching the vehicle 1, if the sound is coming from the front, the recording control unit 32 may start the first camera 12a and start recording the video from the direction from which the sound is coming. This allows a suspicious person approaching the front of the vehicle 1 to be recorded.

[0075] The video recording device 10 may further include a fourth microphone 20d installed at a position capable of picking up sounds mainly from the rear of the vehicle 1. The fourth microphone 20d is also a directional microphone. When it is estimated that a person is approaching the vehicle 1, if the sound is coming from the rear, the recording control unit 32 may start the second camera 12b and start recording the video from the direction from which the sound is coming. This allows a suspicious person approaching the rear of the vehicle 1 to be recorded.

[0076] (Fourth Modification) In the fourth modified example, the arrangement of the microphones 20 is different from that in the first embodiment. Fig. 5 is a top view that shows a schematic diagram of a vehicle 1 in which a video recording device 10B in the fourth modified example is installed. The video recording device 10B includes a second microphone 20b and a third microphone 20c as the microphones 20. The second microphone 20b is the same as in the first embodiment.

[0077] The third microphone 20c is a directional microphone and is installed at a position where it can mainly pick up sounds near the left rear seat. The third microphone 20c can also pick up sounds near the left door of the vehicle 1 and sounds outside the door. An example of a rough sound pickup range Rc of the third microphone 20c is indicated by a dashed line.

[0078] The positional relationship between the first camera 12a and the second microphone 20b included in the first housing installed at the front of the vehicle interior is the same as the positional relationship between the second camera 12b and the third microphone 20c included in the second housing installed at the rear of the vehicle interior. Therefore, by arranging the first housing and the second housing in the opposite direction along the front-rear direction of the vehicle 1, it is possible to collect sounds on the left and right sides of the vehicle 1 as in the first embodiment. The above-mentioned configuration is advantageous in terms of cost effectiveness and reliability due to mass production of the housings, etc., since the component configurations of the first housing and the second housing can be made the same. Also, in a drive recorder, for example, in which only the front first housing is used alone, the second microphone 20b faces in a direction suitable for acquiring the voice uttered by the driver in a right-hand drive vehicle. This results in a rational housing structure even in operations by voice recognition.

[0079] (Fifth Modification) In the first embodiment, two microphones 20 are provided, but only the second microphone 20b may be provided. In this case, when the estimation unit 42 estimates that a person is approaching the vehicle 1, the sound comes from the right side, and the recording control unit 32 activates the fourth camera 12d in the direction from which the sound comes, and starts recording the video in the direction from which the sound comes. In this modified example, the degree of freedom of the configuration of the video recording device 10 can be improved. [Explanation of symbols]

[0080] 1...vehicle, 10, 10A, 10B...video recording device, 12...camera, 12a...first camera, 12b...second camera, 12c...third camera, 12d...fourth camera, 14...first processing unit, 16...first memory unit, 20...microphone, 20a...first microphone, 20b...second microphone, 20c...third microphone, 20d...fourth microphone, 22...vibration sensor, 24...second processing unit, 26...second memory unit, 30...video acquisition unit, 32...recording control unit, 40...sound acquisition unit, 42...estimation unit, 44...monitoring control unit.

Claims

1. a sound acquisition unit that acquires a sound input to a microphone installed in a parked vehicle; an estimation unit that estimates whether or not an object is approaching the vehicle based on the acquired sound; a recording control unit that starts a camera installed in the vehicle and starts recording an image in the direction from which the acquired sound comes when it is estimated that an object has approached the vehicle; A video recording device comprising:

2. The sound acquisition unit acquires a sound input to one or more microphones installed on a front side of the vehicle and a sound input to one or more microphones installed on a rear side of the vehicle, The estimation unit identifies a direction from which a sound comes based on the acquired plurality of sounds.

2. The video recording device according to claim 1.

3. The estimation unit estimates that an object has approached the vehicle when the volume of the acquired sound is equal to or greater than a threshold value and a characteristic related to a frequency of the acquired sound has changed.

3. The video recording apparatus according to claim 1 or 2.

4. The estimation unit is Estimating the location and direction of movement of the captured sound source; When the estimated sound source moves toward the vehicle, the volume of the acquired sound is equal to or greater than a threshold, and the frequency characteristics of the acquired sound change, it is estimated that an object has approached the vehicle.

3. The video recording apparatus according to claim 1 or 2.

5. The estimation unit sets a condition for estimating that an object has approached the vehicle according to a surrounding situation of the vehicle.

3. The video recording apparatus according to claim 1 or 2.

Images