JP3462812B2 - Power supply control method and device for vehicle-mounted camera - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for a vehicle-mounted camera, which is particularly suitable for use in a vehicle monitoring system in which a camera mounted on a vehicle body captures a scene in front of the vehicle and an image recognition device recognizes a traveling condition. The present invention relates to a control method and device.

[0002]

2. Description of the Related Art Recently, a vehicle driving monitoring system using a monocular camera or a stereo camera as a preview sensor has attracted attention. In this surveillance system, a vehicle-mounted camera mounted on the vehicle body captures a scene in front of the vehicle, and the image is recognized based on the captured screen to alert the driver or to downshift by performing downshifting. Perform behavior control. By the way, a CCD (Charge Coupled Device) is usually used as an image sensor of an in-vehicle camera.
Is used. The CCD is a semiconductor light receiving element that converts light into an electric signal, and is a MOS that transfers the load of charges generated when light is applied to the adjacent blocks one after another and converts the electric signal into an electric signal.
The device has a (metal oxide semiconductor) structure. CCDs have the advantages of small size, light weight, long life, impact resistance, high sensitivity, and little image distortion. With the improvement of manufacturing technology, CCDs with a large number of pixels are emerging. .

[0003]

[Problems to be Solved by the Invention] Needless to say, CC
D also has a recommended temperature range for guaranteeing operation. In particular, in a vehicle-mounted camera, a considerable temperature rise is expected under the hot summer of summer, and this cannot be ignored.

FIG. 6 is a graph showing the relationship between temperature and the amount of noise in the video signal with respect to temperature. As is clear from the graph, the noise level tends to increase in proportion to the temperature, so not only is the CCD protected in high temperatures, but the effect of noise is reduced even in high temperatures to provide stable images. A way to get it was desired.

The present invention has been made in view of the above circumstances, and has a temperature sensor mounted in the vicinity of a CCD, an independent power source for a camera, and an energization control including prohibition of power supply to a camera video circuit in an abnormal temperature range. CCD by performing
It is an object of the present invention to provide a power supply control method and device for a vehicle-mounted camera, which protects the above, reduces the influence of noise even in a high temperature range, and stabilizes the quality of the obtained image.

[0006]

In order to solve the above-mentioned problems, a power supply control method for an on-vehicle camera according to the present invention uses a camera mounted on a vehicle body to capture a scene in front of the vehicle, and an image recognition device is used to monitor a running condition. Used in a vehicle monitoring system that recognizes, has a camera power supply that supplies power to the camera independently of the control unit, mounts a temperature sensor in the vicinity of the image sensor of the camera, and specifies in advance via the temperature sensor. Controlling the camera power supply to cut off the power to the camera when a threshold temperature is detected ,
A temperature lower than the specified threshold value after the power is cut off.
Power is supplied to the camera if
That was it. It is also characterized in that an alarm is output to the outside when the camera power supply is controlled and cut off.

As a result, the image pickup device is not used under an unreasonable temperature environment, so that the image pickup device such as CCD can be protected and the quality of the obtained image is stabilized.

In the power supply control device for a vehicle-mounted camera of the present invention, the vehicle-mounted camera that captures a scene in front of the vehicle and generates and outputs a video signal thereof, and an image recognition device that captures and recognizes the video signal form a serial communication path. The vehicle-mounted camera has a camera control unit and a temperature sensor, and has a camera power source independently of the camera control unit, and the image recognition device has the camera through the serial communication path. It is configured to communicate with the control unit and to instruct the camera control unit to perform power supply control including disconnection of the camera power supply when a threshold temperature defined in advance by the temperature sensor is detected.

The on-vehicle camera includes a camera body including an image sensor, a temperature sensor mounted near the image sensor,
A video circuit for generating a video signal from an image captured by the camera body, a camera power supply for supplying power to the camera body and the video circuit, and a threshold value supplied by the recognition device and supplied by the temperature sensor. When a temperature exceeding 0 is detected, the power controller controls the supply of electric power from the camera power source in cooperation with the recognition device. The vehicle-mounted camera is a stereo camera, and the temperature sensor is mounted on at least one of the reference camera and the comparison camera. Further, the recognition device knows the temperature increase exceeding the threshold value by the temperature sensor by polling via the serial communication path, and notifies the outside through an alarm device connected to the outside.

As described above, the temperature sensor is mounted on the vehicle-mounted camera, and the power source of the camera is configured as a power source independent of the control unit, so that the power supply to the camera video circuit is stopped in the abnormal temperature range. This protects the image pickup device such as CCD. Further, the camera control unit and the image recognition apparatus are connected by a serial communication path, and data exchange is performed to control energization, so that the power is simply turned on.
Not only / OFF but also other detailed control can be realized.

[0011]

1 is a view showing the external structure of a vehicle-mounted camera in which the present invention is realized. In-vehicle camera (hereinafter
The chassis 100 of the teleo camera) 1 is made of a highly rigid aluminum alloy so as not to be deformed by the weight of the reference camera 2a and the comparison camera 2b and the acceleration / deceleration during traveling. Chassis 100 located on the right side in the traveling direction
A reference camera 2a is attached to the end of the. A reference image is obtained by an output signal from an image sensor such as a CCD element 2a ' built in the reference camera 2a. On the other hand, the left end portion of the sheet catcher over sheet 100 is mounted is compared camera 2b, comparative image is obtained by the output signal from the comparison camera 2b. Stereo camera 1 (in this case, the reference camera 2a, that the stereo camera assembly assembled with the comparison camera 2b), in the vicinity of the rearview mirror, with an adjuster, not shown, intended to be mounted on the vehicle body.

2 and 3 are views quoted for explaining the internal structure of the vehicle-mounted camera shown in FIG. 1, respectively.
It is the figure which looked at the vehicle-mounted camera from the bottom, and the figure which shows the cross-section of the reference | standard camera 2a, and the mounting component is shown by the dotted line in both.

In the figure, a microcomputer 11, a video circuit (reference camera video circuit 3, comparison camera video circuit 4), a camera power supply 13, and an A / D conversion circuit 15 are mounted on a main board 10, and a CCD board is provided. 20 is a CCD element
In addition to the reference camera 2a having the child 2a ′ as an image sensor, CC
A temperature sensor 14 such as a thermistor is mounted near the D element 2a ' . Here, it is assumed that the temperature sensor is not mounted on the comparison camera 2b. The thermistor used as the temperature sensor 14 utilizes the fact that the resistance R of a semiconductor in which oxides such as Mo, Ni, and Co are appropriately mixed so as to obtain the required resistivity and temperature coefficient changes with temperature.

Reference numeral 21 denotes a connector to which a power source line 34, which will be described later, and a bus to be the serial communication path 31 are connected,
22a is a reference video signal line (hereinafter referred to as a video signal line
32) is connected to the connector, and 22b is connected to a comparison video signal line (hereinafter referred to as a video signal line) 33.
It is a connector to be continued . Further, 23 and 24 are lens hoods for protecting each camera lens.

FIG. 4 is a block diagram showing the internal structure of a vehicle monitoring device in which the present invention is implemented.
The blocks with the same numbers as the blocks shown in FIG. 2 are the same as those shown in FIGS. In FIG. 4, a stereo camera 1 and an image recognition device (hereinafter referred to as a recognition device)
30 are connected via a serial communication path 31.
The stereo camera 1 captures a scene in front of the vehicle and generates and outputs a video signal thereof. The recognition device 30 exchanges the data via the serial communication path 31 while transmitting the video signal to the video signal line 32. , 33 for recognition.

The stereo camera 1 includes a control unit 11 having a microcomputer as a control center, a reference camera 2a, a comparison camera 2b, and an image capturing unit 12 (shaded portions in the figure) including the video circuits 3 and 4. The camera power supply 13 that supplies power to the image capturing unit 12 independently of the control unit 11, the temperature sensor 14 such as a thermistor, and the control unit 11 by converting the output of the temperature sensor 14 into a digital signal.
It is composed of an A / D conversion circuit 15 for transmitting to

The recognition device 30 includes video signal lines 32, 3
3, the power is supplied to the control unit 11 of the stereo camera 1 via the power line 34, and status information is obtained by polling with the control unit 11 via the serial communication path 31. Acquire, camera power supply 13 described later
Control. The recognition device 30 is connected to a control device 40 that obtains a recognition result to monitor the vehicle and an alarm device 50 that includes an indicator in the instrument panel.

FIG. 5 is a flow chart showing the operation of the control unit 11 with a built-in stereo camera shown in FIG. 4. Specifically, the control procedure of the software recorded in the ROM (not shown) built in the control unit 11 is shown. Only the portions related to the present invention are extracted and shown.

The operation of the embodiment of the present invention shown in FIGS. 1 to 4 will be described in detail below with reference to the flow chart shown in FIG.

During normal operation, the image capturing unit 12 of the stereo camera 1 is driven by an independently prepared camera power source 13, and images captured by the reference camera 2a and the comparison camera 2b are imaged by the respective video circuits 3 and 4. The signal is converted into a signal, and the recognition device 30 is supplied via the video signal lines 32 and 33, respectively.
Supply to. As a result, the recognition device 30 recognizes, for example, a road shape or a three-dimensional object including a traveling vehicle in front of the vehicle, which is the result of the image capturing. This recognition is performed based on image data stored in an image data memory (not shown) or navigation information. Recognition device 30
When it is determined that the alarm is necessary based on the recognition result and the behavior state of the vehicle, the alarm device 50 is activated to call the driver's attention. Here, an indicator provided on the instrument panel is turned on, or a buzzer or the like is used for notification. Also, automatically performed by controlling via the control device 40 AT downshift and the engine output control, such as the (automatic transmission), or vehicle in control that is effected actuation trough of the brake as required.

On the other hand, the recognition device 30 polls the control unit 11 of the stereo camera 1 at regular time intervals to receive various status information of the stereo camera 1. Of the status information, the temperature is shown as an example.
1 is always monitoring the output from the temperature sensor 14, when the recognition unit 30 receives the polling (step S51), the relationship between the advance CCD temperature and Bruno <br/> size b of the video signal Only when the temperature rise exceeds the threshold level defined based on the above (step S52),
This is notified to the recognition device 30 via the serial communication path 31 (step S53: status information notification).

The recognizing device 30 knows that the temperature rise exceeds the threshold level as the status information, and controls to stop the power supply from the camera power supply 13 which is the power driving source of the stereo camera 1 if necessary. Instruct the section 11. The control unit 11 receives this instruction via the serial communication path 31 (step S54), controls the camera power supply 13 via the built-in input / output port, and sets the reference camera 2a,
The power supply to the image capturing unit 12 including the comparison camera 2b and the video circuits 3 and 4 is stopped (step S55). Since the drive power of the control unit 11 is supplied through the power supply line 34 and the recognition device 30, even if the power supply from the camera power supply 13 is stopped, the operation is not affected.

Further, regarding this (the camera cannot operate due to the interruption of the camera power supply 13), the control unit 11 causes the control device 40 to operate.
In order to notify the operator including, the alarm device 50 is driven via the recognition device 30 (step S56). The indicator ON of the alarm device 50 indicates that the information indicating that the power supply from the camera power supply 13 is prohibited from the control unit 11 is used as status information via the serial communication path 31 to recognize the device 3.
0 is received, and the recognition apparatus 30 recognizes this, and it is performed. As described above, according to the present invention, the temperature sensor is mounted in the vicinity of the image pickup device such as CCD, the camera power source is independent, and the power supply to the camera video circuit is prohibited in the abnormal temperature range where a large amount of noise is superimposed on the video signal. By controlling the energization including the above, the image sensor such as CCD is protected, and it is not used in an unreasonable temperature environment.
The image quality can be stabilized.

Although not shown, when the detected value of the temperature sensor 14 falls below a predetermined threshold level, the power supply from the camera power supply 13 to the image capturing section 12 is restarted. Although the thermistor is used as the temperature sensor in the embodiment of the present invention, the temperature sensor is not limited to this element, and another temperature sensor may be used instead. Further, although the example in which the temperature sensor is mounted only on the reference camera has been described, the temperature sensor may be mounted on the comparative camera or both. Further, although the stereo camera is exemplified as the vehicle-mounted camera, the same control is possible even with a monocular camera.

[0025]

As described above, according to the present invention, a power supply for supplying electric power to a vehicle-mounted camera is provided independently of the control unit, and a temperature sensor is mounted in the vicinity of the image sensor of the camera, by controlling the camera power when it detects a threshold temperature defined by the relationship between the noise <br/> amount in advance the video signal through the sensor, protection such as a CCD imaging element Hakare obtained Image quality is stabilized. The ON / OFF control of the camera power supply is performed by data exchange between the vehicle-mounted camera and the recognition device.
Not only the ON / OFF control of the camera power supply due to the rise in environmental temperature, but also the turning on of the alarm indicator that notifies this
/ OFF, and by using a timer, fine power control such as prohibiting power supply when the camera is not used for a certain period of time becomes possible.

[Brief description of drawings]

FIG. 1 is a diagram showing an external structure of a vehicle-mounted camera according to the present invention.

FIG. 2 is a diagram showing an arrangement of mounting components of the vehicle-mounted camera according to the present invention.

FIG. 3 is a diagram showing an arrangement of mounted components around a reference camera in FIG.

FIG. 4 is a block diagram showing an embodiment of a vehicle monitoring device in which the present invention is realized.

5 is a flowchart showing the operation of the control unit in FIG.

FIG. 6 is a graph showing the relationship between temperature and the amount of noise in the video signal with respect to temperature.

[Explanation of symbols]

1 ... vehicle-mounted camera, 2a ... standard camera, 2b ... comparison camera, 3 (4) ... video circuit, 10 ... main board, 11 ... control part, 12 ... image acquisition circuit, 13 ... camera power supply, 1
4 ... Temperature sensor, 15 ... A / D conversion circuit, 20 ... CCD
Substrate, 30 ... Recognition device, 31 ... Serial communication path, 34 ...
Power line, 40 ... Control device, 50 ... Alarm device

Claims (6)

(57) [Claims] 1. A camera power supply for use in a vehicle monitoring system, wherein a camera mounted on a vehicle body captures a scene in front of a vehicle and an image recognition device recognizes a traveling condition, and a camera power supply for supplying power to the camera is a control unit. In addition to having it independently, a temperature sensor is mounted in the vicinity of the image pickup element of the camera, and the camera power source is controlled to detect the predetermined threshold temperature via the temperature sensor, thereby controlling the camera.
Disconnecting the power to a temperature below the specified threshold after disconnecting the power.
Power is supplied to the camera if
Power control method for onboard cameras, characterized in that that. 2. The power control method for a vehicle-mounted camera according to claim 1, wherein an alarm is output to the outside when the camera power is controlled and cut off. 3. An in-vehicle camera that captures a scene in front of the vehicle and generates and outputs a video signal thereof, and an image recognition device that captures and recognizes the video signal are connected via a serial communication path, and the in-vehicle camera is In addition to having a camera control unit and a temperature sensor, a camera power supply for supplying power to the camera is provided independently of the camera control unit, and the image recognition device has the camera control unit via the serial communication path. Communicate with
A power control device for a vehicle-mounted camera, which instructs the camera control unit to perform power control including disconnection of a camera power when a threshold temperature defined in advance by the temperature sensor is detected. 4. The vehicle-mounted camera, a camera body including an image sensor, a temperature sensor mounted near the image sensor, a video circuit for generating a video signal from an image captured by the camera body, and the camera. A camera power supply for supplying power to the main body and the video circuit, and when the recognition device supplies power and a temperature exceeding a certain threshold is detected by the temperature sensor, the camera cooperates with the recognition device. The power supply control device for the vehicle-mounted camera according to claim 3, further comprising a power supply control unit that controls the supply of electric power from the power supply. 5. The power supply for a vehicle-mounted camera according to claim 4, wherein the vehicle-mounted camera is a stereo camera, and the temperature sensor is mounted on at least one of a reference camera and a comparison camera. Control device. 6. The recognizing device is notified of an increase in temperature exceeding a threshold value by a temperature sensor by polling via a serial communication path, and notifies the outside through an alarm device connected to the outside. The power supply control device for the vehicle-mounted camera according to item 1.