JPH07131688A - Camera monitoring device - Google Patents

Abstract

PURPOSE:To simplify the constitution or a camera monitoring device and to reduce the influence due to the fluctuation of the high band component of a video signal in a detection state of dew condensation by detecting electrically the dew condensation based on the high band component level of the video signal. CONSTITUTION:The high band component of the video signal sent from a camera circuit 13 is separated from other components by a filter circuit 15 and transferred to a detection circuit 16. The circuit 16 detects its input signal and sends the detection output to a dew condensation detecting circuit 17. The circuit 17 compares the output received from the circuit 16 with the reference signal which is previously set and acquired from the video signal when no dew condensation is detected. Thus it is decided whether the video signal was transmitted through the surface of dew condensation. Then a state detecting circuit 18 detects the output of the circuit 17 and decides whether the output state is held for a period longer than a prescribed time. Then the circuit 18 decides whether the output of the circuit 17 is caused temporarily by a large vibration, etc. Then the result of detection of the circuit 18 is supplied to a heater control circuit 17, and the energization applied to a conductor film is controlled based on the result of detection of the circuit 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a camera monitoring device, and more particularly to
In a surveillance camera device or an in-vehicle camera surveillance device used outdoors, the invention relates to a camera surveillance device for preventing dew condensation, frozen matter removal, and adhesion that occur on glass attached to the front surface of a case in which a camera is housed. Is.

[0002]

2. Description of the Related Art Generally, a surveillance camera is usually used outdoors, and particularly in an on-vehicle surveillance camera installed for safety confirmation or safe driving behind a vehicle, an environment such as a sudden temperature change may occur. Due to the change, dew condensation or adhesion of frozen matter may occur on the glass portion on the front surface of the case, which may prevent a good visibility from being obtained.

Regarding such a surveillance camera, an example of a surveillance camera device having a function of preventing dew condensation on the front glass portion of the case and adhesion of frozen substances has been disclosed in Japanese Patent Laid-Open No. 300715/1990.

In the technique disclosed in this publication, a glass is added to the front surface of the image pickup portion of the camera, a conductive film is formed on the back surface of the glass to have a heater function, and the glass surface is heated by energization to cause dew condensation. And prevents freezing.

Further, the temperature sensor for controlling the heater function of the conductive film on the glass surface is installed inside or outside the case accommodating the camera, and the temperature in the air inside the case becomes lower than a predetermined set temperature. Alternatively, the conductive film is energized by detecting that the temperature difference between the inside and the outside has reached a predetermined value.

Further, in order to more reliably control the heater function of the conductive film on the glass surface, the surface of the glass surface,
A dew condensation sensor is installed on the back or front and back, or a conductive film with a heater function and a dew sensor are integrated and formed on the glass surface to detect the dew condensation on the glass surface and the state of adhesion of frozen material to conduct electricity. There are those in which the film is energized, and those in which the energization of the conductive film is controlled by the output of the level detection circuit of the high frequency component of the video signal of the camera device.

[0007]

However, in the above-mentioned conventional vehicle-mounted camera monitoring device, a temperature sensor is installed inside or outside the case for housing the camera body, or a dew condensation sensor is installed on the cover glass surface of the front part of the case. In addition, the dew condensation sensor on the cover glass surface is detected by integrating the conductive film with a heater function and the dew condensation sensor, which makes the structure of the camera device complicated and The processing of the conductive film on the surface was complicated.

Further, in the case where the conduction of the conductive film is controlled by the output of the level detection circuit of the high frequency component of the video signal of the camera device, the temperature and the condensation sensor are not required, so the structure of the camera device and the processing of the glass surface are performed. Although it is simpler, the output of the level detection circuit is used as it is to detect the state of the glass surface, so when the high frequency component is temporarily reduced due to the vibration of the camera device etc. I had to make it work.

By solving the above-mentioned conventional problems, the present invention has a simple mechanical structure and can accurately detect the dew condensation state of the cover glass to control the heater to obtain a good visual field at all times. It is to provide a camera monitoring device.

[0010]

In order to achieve the above object, the present invention is a camera monitoring device comprising a camera device for picking up an image of a subject and a monitor device for displaying a video output from the camera device. The camera monitoring device according to claim 1, wherein a cover glass is attached to a front surface of a case that houses the main body, and a translucent conductive film having a heater function is formed on a front surface or a back surface of the cover glass. , A control for controlling the energization of the conductive film by providing a level detection circuit for detecting the output state of the level detection circuit by providing a level detection circuit for the high frequency component of the video signal imaged by the camera device A circuit is provided and configured.

According to a second aspect of the present invention, there is provided a camera monitoring device, which is provided with a clarity detection circuit for performing image processing for detecting the clarity of the image of a video signal picked up by the camera device, and outputs the output of the clarity detection circuit in advance. A comparator circuit for comparing with the set reference level is provided, and a control circuit for controlling the conduction of the conductive film by the output of the comparator circuit is provided.

According to a third aspect of the present invention, there is provided a camera monitoring device, which is provided with a clarity detection circuit for performing image processing to detect the clarity of the image of the video signal picked up by the camera device, and detects the luminance component of the video signal. A detection circuit is provided, and a reference level control circuit for determining the condensation state from the output signal from the detection circuit according to the imaging environment is provided, and the reference signal controlled according to the output of the intelligibility detection circuit and the imaging environment. And a control circuit for controlling the conduction of the conductive film by the output of the comparison circuit.

According to a fourth aspect of the present invention, there is provided a camera monitoring device, which is provided with a level detection circuit for a video signal picked up by the camera device, and a clarity detection circuit for image processing for detecting the clarity of a video. , And an intelligibility detection circuit each provided with a comparison circuit for comparing with a reference level for detecting a dew condensation state, and a control circuit for controlling conduction of a conductive film by outputs of both comparison circuits. .

[0014]

According to the present invention, in the above structure, the dew condensation or freezing condition of the glass mounted on the front surface of the case in which the camera is housed is detected from the transmitted light on the glass surface.
The glass surface can be electrically processed without complicated processing, and the structure of the device can be simplified. Further, even in the case where the vehicle-mounted camera monitoring device is susceptible to vibration or the like, the condition of dew condensation on the glass surface can be detected to control the heater, and a good field of view can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a camera monitoring apparatus of the present invention will be described below with reference to the drawings. FIG. 1 shows a car 1 equipped with a rear monitoring camera 2, and the car 1 is further equipped with a display 3 for monitoring an image captured by the camera 2.

FIG. 2 is a perspective view showing the surveillance camera 2. The camera body 4 is housed in a case 5. Camera body 4
An opening for taking in an image is provided on the front wall of the case 5 facing the image pickup optical system, and is covered with a cover glass 6 to protect the camera body 4 from the external environment.

FIG. 3 is an exploded view of a structure in which the opening of the front wall of the case is covered with a cover glass 6, and one surface of the cover glass 6 has a packing material 8a for waterproofing and insulating, and the front wall 5A of the case. In addition, the other surface faces the front cover 9 via the packing material 8b and is hermetically sealed in order to protect the inside of the case from the external environment.

By the way, when riding in a car on a rainy day and running with the windows closed, the window glass becomes cloudy, and when the car is run on a cold day, the window glass becomes cloudy.
Because the air inside the car touches the cold window glass to cause condensation,
Similarly, in the surveillance camera 2 as well, when the cover glass 6 surface is rapidly cooled due to car washing or rain, a temperature difference of a certain temperature or more occurs between the air inside the case and the air outside the case, and dew condensation occurs on the cover glass 6 surface. To do. This is because the water vapor in the air that is in contact with the surface of the cover glass 6 is condensed and water droplets are attached to the surface.
It is necessary to raise the temperature of the cover glass 6 so that the water vapor in the air in contact with is not condensed.

A transparent conductive film 7 is formed on the surface (one surface or both surfaces) of the cover glass 6 by vapor deposition or by depositing a conductive thin film. The conductive film 7 is formed so as to cover the entire surface of the cover glass 6. The conductive film 7 is formed of a conductive film material having a property of generating heat when energized. The conductive film 7 on the surface of the cover glass 6 can be formed on only one glass surface, but it is desirable to form it on both the front and back surfaces of the cover glass 6.

The cover glass 6 that normally faces the inside of the case
Condensation often forms on the back of the. This is because when the air outside the case is cooled more rapidly than inside the case, the water vapor inside the case that contacts the surface of the cover glass 6 condenses, and water drops adhere to the back surface of the cover glass 6. In this case, the conductive film on the back surface can achieve the purpose of removing dew condensation, but when the camera unit is exposed to high temperature rapidly from being cold, the cover glass will be exposed if the temperature outside the case rises sharply. Condensation forms on the surface of 6.

By forming the conductive films 7 on both surfaces as in this embodiment, even if dew condensation occurs on any surface of the cover glass 6, it can be removed. Also, in the case of adhesion of frozen material, it is possible to remove the frozen material more quickly by forming the conductive films 7 on both surfaces.

FIG. 4 shows the above-mentioned vehicle-mounted surveillance camera,
It is a block diagram explaining the electric control of the camera monitoring apparatus performed using the video signal which permeate | transmitted the cover glass 6.
Power from the battery 10 is supplied to the vehicle-mounted surveillance camera 2. The camera 2 has a built-in power supply circuit 11, and stabilizes the output voltage so that it does not change due to fluctuations in the battery voltage, while performing the signal processing for capturing the video signal and displaying it on the monitor, and the conductive film 7. The necessary voltage is supplied to the heater control circuit 12 that controls the energization of the heater.

The drive circuit 14 provided in the camera 2 supplies power from the power supply circuit 11 to the heater control circuit 12 or the camera circuit 13 when necessary as described below. For example, when the car key is inserted and the engine is operating, power is supplied to the heater control circuit 12 so that the conductive film 7 can be energized so that it can function as a heater, and the gear is changed to the back gear. At this time, a gear change signal is input to supply power from the power supply circuit 11 to the camera circuit 13 and the heater control circuit 12.

When the engine is started by the operation of the drive circuit 14, power is supplied to the camera circuit 13 and the heater control circuit 12, and dew condensation is detected by using the picked-up video signal. The energization of 7 is controlled so that the camera circuit 13 is energized while the heater is energized. When the power supply to the heater is finished, the power supply to the camera circuit 13 is also finished. Even when the back gear is checked backward even after the power is turned on, the power is supplied to the camera circuit 13 and the heater control circuit 12, and the conductive film heater is controlled according to the dew condensation detection result.

When the surface of the cover glass 6 is dewed,
The video signal transmitted through the condensed cover glass 6 and taken into the camera 2 has a characteristic that high frequency components are reduced. However, in addition to the dew condensation state on the surface of the cover glass 6, the high frequency component of the video signal may be temporarily reduced due to a large vibration or the like.

Therefore, in the present invention, in consideration of the above, a level detection circuit for the high frequency component of the video signal is provided, and further a state detection circuit for detecting the output state of the level detection circuit is provided, and the state detection circuit is provided. Dew condensation shall be judged by the output of.

A filter circuit 15 to which a video signal from the camera circuit 13 is input is provided, and the filter circuit 15 is provided.
The high frequency component of the video signal is separated by and is transferred to the detection circuit 16 provided in the next stage. The detection circuit 16 detects the input signal and outputs the output to the dew condensation detection circuit 17. The dew condensation detection circuit 17 compares the output from the detection circuit 16 with a preset reference signal obtained from the video signal when there is no dew condensation, and determines whether the video signal has passed through the dew condensation surface.

The state detection circuit 18 detects the output of the dew condensation detection circuit 17 and determines whether the output state is held for a preset time or longer, and the dew condensation detection circuit 17 is detected.
Determines whether the output of is temporary due to a large vibration, etc., and outputs. The detection result of the state detection circuit 18 is input to the heater control circuit 12 and controls energization of the conductive film 7 according to the detection content.

FIG. 5 does not detect the dew condensation state of the glass surface 6 by the level detection circuit and the state detection circuit of the high frequency component of the video signal picked up by the camera device. When the dew condensation on the glass surface 6 that has an effect on the surface of the cover glass 6 is blurred, the image is blurred and indistinct (image state like through a frosted glass). It is a block diagram of the electric control part of what does.

A sync separation circuit 19 to which the brightness signal from the camera circuit 13 is input is provided, and the brightness signal whose synchronization is separated by this sync separation circuit 19 is divided into two, and one is input to the delay circuit 20. The other one of the luminance signals that have been synchronously separated and the luminance signal delayed through the delay circuit 20 are input to the subtraction circuit 21 in the next stage. The subtraction circuit 21 subtracts the delayed luminance signal from the non-delayed luminance signal and outputs the difference signal between the two signals. Here, there is a characteristic that the higher the clarity of the image of the video signal from the camera device, the larger the output amplitude from the subtraction circuit 21. This means that the high clarity of the image means that the brightness of the screen is clear, so that the amplitude of the luminance signal becomes large and the output amplitude of the subtraction circuit becomes large. Further, when dew condensation that affects the field of view occurs on the glass surface 6 to the extent that the contour of the subject is unknown, the image is blurred and the change in the luminance signal is gradual, and the output amplitude of the subtraction circuit 21 is small. Become.
The output of the subtraction circuit 21 is input to the next-stage full-wave rectification circuit 22 and full-wave rectified. The output of the full-wave rectifier circuit 22 is input to the peak detection circuit 23 at the next stage. Peak detection circuit 2
The peak value detected in 3 is input to the next stage dew condensation detection circuit 24. The dew condensation detection circuit 24 compares the input peak value with a preset reference value to determine the dew condensation state of the glass surface 6. The detection result of the dew condensation detection circuit 24 is input to the heater control circuit 12 and controls the energization of the conductive film 7 according to the detection content. According to this dew condensation detection method, the clarity of the entire screen is detected as compared with the case of the high frequency signal of the video signal, so that it is less likely to be affected by vibration or the like.

Since the output amplitude of the subtraction circuit 21 changes depending on the ambient illuminance even when the same subject is imaged, a reference signal for determining the dew condensation is output according to the ambient illuminance. Need to control. Therefore, a function of adjusting according to the surrounding environment of image pickup is added.

In order to adjust the level of the reference signal,
A luminance detection circuit 25 is provided and the output of the sync separation circuit 19 is input to this circuit. The luminance component is detected by the luminance detection circuit 25 to form an output signal for determining the imaging environment. The output signal of the luminance detection circuit 25 is input to the reference signal control circuit 26, forms a signal for adjusting the reference level, and corrects the level of the reference signal preset in the dew condensation detection circuit 24 according to the imaging environment. . The dew condensation detection circuit 24 determines the dew condensation by using the corrected reference signal, and controls the power supply to the conductive film 7.

Further, the dew condensation detection based on the clarity of the image has a characteristic that it is hardly affected by vibration and the like, and the dew condensation on the glass surface 6 affects the visual field to the extent that the contour of the subject is unknown. Occasionally, it is possible to detect dew condensation accurately, but in a dew condensation situation in which the influence on the field of view is relatively small, the clarity of the image does not deteriorate so much, so it is possible that dew condensation cannot be detected accurately.

In the dew condensation detection by detecting the level of the high frequency component of the video signal, when dew condensation occurs on the glass surface 6, the dew condensation affects the high frequency component of the distorted image. Although dew condensation can be detected regardless of the situation, it is possible that dew condensation cannot be accurately detected due to temporary influence of fluctuations in the high frequency components of the image due to vibrations and the like.

Therefore, by using both the dew condensation detection based on the clarity of the image and the dew detection based on the level detection of the high frequency component of the image, the dew condensation state of the glass surface 6 and the influence of vibration etc. Moreover, dew condensation can be detected.

[0036]

According to the invention of claim 1, since the camera monitoring apparatus of the present invention has the above-mentioned structure, the dew condensation is electrically detected by the high frequency component level of the video signal.
The mechanical structure of the device can be simplified. In addition, it is possible to provide the one that is not easily affected by the temporary fluctuation of the high frequency component of the video signal due to vibration or the like at the time of detection.

According to the second aspect of the present invention, since the dew condensation is electrically detected by the clarity of the image obtained by processing the image signal from the camera device, the mechanical structure of the device is simple. Can be In addition, since the clarity of the image has a characteristic that it is not easily affected by vibration etc. as described above, when the dew condensation that affects the visibility is generated on the glass surface so that the contour of the subject is unknown, the vibration etc. It is possible to provide a device that can be accurately detected regardless of the above.

According to the third aspect of the present invention, since the dew condensation is electrically detected by the clarity of the image obtained by processing the image signal from the camera device, the mechanical structure of the device is simple. Can be In addition, the clarity of the image has the characteristic that it is not easily affected by vibration as described above, so if the dew condensation that affects the field of view occurs on the glass surface so that the contour of the subject is unknown. It can be detected accurately regardless of the above. Furthermore, by adding the correction of the imaging condition at the time of detection, it is possible to provide the one which is not easily affected by the surrounding environment of the camera device.

Further, according to the invention of claim 4, since the dew condensation is electrically detected by the high frequency component level of the video signal and the clarity of the video obtained by image processing the video signal, the machine of the apparatus is Structure can be simplified. Moreover, as described above, it is possible to provide a camera monitoring device that is not easily affected by vibrations and the like and that can detect dew condensation on the glass surface appropriately regardless of the degree of dew condensation on the glass surface.

[Brief description of drawings]

FIG. 1 is an external perspective view of a vehicle equipped with an in-vehicle camera that is an embodiment of a camera monitoring device of the present invention.

FIG. 2 is a partially exploded perspective view of a surveillance camera which is an embodiment of the camera surveillance device of the present invention.

FIG. 3 is an exploded view of a main part of a cover glass mounting portion on a front surface of a case of a surveillance camera which is an embodiment of the camera surveillance device of the present invention.

FIG. 4 is a block diagram illustrating a dew condensation detecting operation of a surveillance camera which is an embodiment of the camera surveillance apparatus of the present invention.

FIG. 5 is a block diagram illustrating a dew condensation detecting operation of a surveillance camera that is another embodiment of the camera surveillance apparatus of the present invention.

[Explanation of symbols]

 2 Surveillance camera 4 Camera body 5 Camera body case 6 Cover glass 7 Conductive film 11 Power supply circuit 12 Heater control circuit 13 Camera circuit 14 Drive circuit 15 Filter circuit 16 Detection circuit 17 Condensation detection circuit 18 Status detection circuit 19 Sync separation circuit 20 Delay circuit 21 Subtraction circuit 22 Full wave rectification circuit 23 Peak detection circuit 24 Condensation detection circuit 25 Luminance detection circuit 26 Reference signal control circuit

Claims (4)

[Claims] 1. A camera device for mounting a cover glass on a front surface of a case for accommodating a camera body, and imaging a subject having a transparent conductive film having a heater function formed on the cover glass surface, and the camera device. In a camera monitoring device comprising a monitor device for displaying the video output of the above, a state detection circuit for detecting the output state of the level detection circuit is provided with a level detection circuit for a high frequency component of a video signal imaged by the camera device. And a control circuit for controlling the conduction of the conductive film by the output of the state detection circuit to automatically remove the dew condensation on the surface of the cover glass. 2. A camera device for mounting a cover glass on a front surface of a case for accommodating a camera body, and imaging a subject having a transparent conductive film having a heater function formed on the cover glass surface, and a camera device comprising: In a camera monitoring device comprising a monitor device for displaying the video output of the device, an intelligibility detection circuit for performing image processing for detecting the intelligibility of an image of a video signal picked up by the camera device is provided. A camera monitoring device characterized in that a control circuit for controlling the conduction of a conductive film is provided by comparing the output of the circuit with a preset reference level to automatically remove the dew condensation on the cover glass surface. 3. A camera device for mounting a cover glass on a front surface of a case for accommodating a camera body, and imaging a subject having a transparent conductive film having a heater function formed on the cover glass surface, and the camera device. In a camera monitoring device provided with a monitor device for displaying the video output of the video signal, an intelligibility detection circuit for performing image processing to detect the intelligibility of the video image of the video signal captured by the camera device is provided, A reference level control circuit for controlling a reference level for determining the condensation state according to the imaging environment from the signal obtained by detecting the luminance component is provided, and the output of the intelligibility detection circuit is a reference signal controlled according to the imaging environment. In comparison, a surveillance camera device is provided which is provided with a control circuit for controlling the energization of the conductive film to automatically remove the dew condensation on the cover glass surface. 4. A camera device for mounting a cover glass on a front surface of a case for accommodating a camera body, and imaging a subject having a transparent conductive film having a heater function formed on the cover glass surface, and the camera device. In a camera monitoring device comprising a monitor device for displaying the video output of the device, a level detection circuit for a video signal picked up by the camera device and an intelligibility detection circuit for image processing to detect the intelligibility of the image are provided. , The level detection circuit and the intelligibility detection circuit each determine a dew condensation state, and a control circuit for controlling the conduction of the conductive film according to the detection result is provided to automatically remove the dew condensation on the cover glass surface. Surveillance camera device.