JP4604394B2 - Surveillance camera device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surveillance camera device, and relates to an apparatus that detects and alerts when the front of a surveillance camera is covered.
[0002]
[Prior art]
When a surveillance camera becomes unmonitorable, the coping method differs depending on what causes the unmonitorable cause, so it is important to determine the cause of unmonitorable. One of the causes is that the front of the surveillance camera is covered with something and the field of view is blocked. Conventionally, when the field of view of the surveillance camera is obstructed and the screen becomes dark, the auxiliary illumination provided in the vicinity of the surveillance camera is turned on to cover and reflect the light of the auxiliary illumination. Some have detected that the field of view of the surveillance camera is covered based on an increase in brightness (average value of the video signal level from the surveillance camera). However, since the level of the video signal output from the surveillance camera is corrected by AGC (automatic gain control) and electronic shutter control, the output video signal level may not increase even when the auxiliary illumination is turned on. In some cases, it was impossible to determine from the change in screen brightness that the front was covered.
[0003]
[Problems to be solved by the invention]
The present invention turns on / off the auxiliary illumination based on the AGC voltage for controlling the amplification gain and the speed of the electronic shutter, and based on the AGC voltage, the shutter speed and the on / off status of the auxiliary illumination at this time. It is an object to improve the accuracy of covering determination by determining whether or not the front of the surveillance camera is covered.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, a surveillance camera device of the present invention inputs a surveillance camera, auxiliary illumination provided in the vicinity of the surveillance camera, and a video signal from the surveillance camera, and changes the level of the video signal. The AGC unit that varies the AGC (automatic gain control) voltage and controls the amplification gain to output to the monitor, and the electronic shutter speed of the monitoring camera according to the fluctuation in the level of the video signal output from the AGC unit The brightness of the visual field of the surveillance camera is determined based on the AGC voltage of the AGC unit and / or the shutter speed of the shutter control unit, and the auxiliary illumination is turned on or off based on the determination A brightness determination unit to be determined; an illumination control unit that turns on or off the auxiliary illumination based on the determination of the brightness determination unit; an AGC voltage of the AGC unit; A cover determination unit that determines whether the field of view of the monitoring camera is covered based on the shutter speed by the shutter control unit, the determination of brightness by the brightness determination unit, or the determination of whether the auxiliary illumination is turned on or off. An alarm unit that warns that the visual field of the monitoring camera is covered when the cover determination unit determines that there is a cover is provided.
[0005]
The brightness determination unit determines that the field of view of the monitoring camera is bright when the AGC voltage of the AGC unit is equal to or higher than a first threshold value, and is dark when the AGC voltage is equal to or lower than a second threshold value, or the shutter control unit When the shutter speed by the camera is greater than or equal to the third threshold, the field of view of the surveillance camera is bright, and when the shutter speed is less than or equal to the fourth threshold, it is determined that the field is dark, or the shutter speed by the shutter controller is greater than or equal to the third threshold In this case, it is determined that the field of view of the monitoring camera is dark when the field of view of the monitoring camera is bright and the AGC voltage of the AGC unit is equal to or lower than a second threshold.
[0006]
When the auxiliary lighting is turned on when the auxiliary lighting is turned on based on the determination of the brightness determining unit, the cover determining unit determines whether the auxiliary lighting is turned off, or for determining the brightness determining unit Based on this, when the auxiliary illumination is turned off, the brightness determination unit determines that the auxiliary illumination is turned on when the auxiliary illumination is turned on. Or, when the auxiliary lighting is turned on / off by the illumination control unit, the AGC voltage change of the AGC unit is less than a predetermined width, or the change of the shutter speed by the shutter control unit is less than the predetermined width, there is a cover judge.
[0007]
Alternatively, when the auxiliary illumination is turned on / off by the illumination control unit, the AGC voltage of the AGC unit is near the lower limit of the control range, and it is determined that there is a cover when the change in the AGC voltage is equal to or less than a predetermined width.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on examples with reference to the drawings.
FIG. 1 is a block diagram showing the main part of an embodiment of the surveillance camera apparatus according to the present invention. In the figure, reference numeral 1 denotes an image pickup unit of a surveillance camera, which uses a solid-state image pickup device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxided Semiconductor), and 2 denotes a video signal from the image pickup unit 1 to change in level. An AGC unit that varies the AGC voltage and outputs the gain after controlling the amplification gain, 3 is a shutter control unit that controls the electronic shutter speed of the image pickup unit 1 in accordance with a change in the level of the video signal output from the AGC unit 2; 4 is a monitor that displays video based on the video signal from the AGC unit 2, 5 is to determine the brightness of the field of view of the imaging unit 1 based on the AGC voltage of the AGC unit 2 and / or the shutter speed by the shutter control unit 3, A brightness determination unit that determines whether to turn on or off the auxiliary illumination 7 based on this determination, and 6 denotes an illumination control unit that turns on or off the auxiliary illumination 7 based on the determination of the brightness determination unit 5. 7 is provided in the vicinity of the imaging unit 1, and 8 is an AGC voltage of the AGC unit 2, a shutter speed by the shutter control unit 3, or a brightness determination by the brightness determination unit 5 or a decision to turn on / off the auxiliary illumination. A cover determination unit 9 that determines whether or not the field of view of the image pickup unit 1 is covered, and an alarm unit 9 that warns that the image pickup unit 1 is covered when the cover determination unit 8 determines that the cover is covered.
[0009]
Next, the operation of the surveillance camera device according to the present invention will be described with reference to the explanatory diagrams of the AGC and shutter speed control range of FIG.
The video signal from the imaging unit 1 of the surveillance camera is controlled to a certain level by the AGC unit 2 and the shutter control unit 3 and is input to the monitor 4. When the video signal input level is greater than or equal to a in FIG. 2, the AGC unit 2 controls the amplification gain by varying the AGC voltage so that the video signal output level is constant, and the video signal input level is controlled by the AGC unit 2. When the value exceeds b beyond the range (ab in FIG. 2), the shutter control unit 3 changes the shutter speed of the imaging unit 1 and controls the video signal output level to be constant. The shutter control unit 3 increases the number of shutter pulses when the visual field of the imaging unit 1 is bright and the video signal output level is high, shortens the charge accumulation time of the solid-state imaging device, and lowers the video signal level. Is dark and the video signal level is low, the number of shutter pulses is reduced, and the charge accumulation time of the solid-state imaging device is lengthened to increase the video signal level. That is, the AGC voltage of the AGC unit 2 and the shutter speed of the shutter control unit 3 are indicators of the brightness of the field of view of the imaging unit 1.
[0010]
FIG. 3 is a flowchart of the operation when both the imaging unit 1 and the auxiliary illumination 7 are covered. The screen from the imaging unit 1 becomes bright when the auxiliary illumination 7 is turned on, but becomes dark when the auxiliary illumination 7 is turned off. To do. That is, when the field of view of the imaging unit 1 becomes dark, the output video signal level (average luminance of the image) decreases. Therefore, in order to increase the amplification gain of the AGC unit 2, the AGC voltage is lowered in the case of the forward AGC type, The shutter speed by the shutter control unit 3 is lowered so that the video signal level sent to the monitor 4 becomes constant. Control signals for the AGC voltage of the AGC unit 2 and the shutter speed of the shutter control unit 3 are input to the brightness determination unit 5. The brightness determination unit 5 determines whether the AGC voltage is equal to or higher than the first threshold value (predetermined gain), the shutter speed is equal to or higher than the third threshold value (predetermined speed), or the AGC voltage is equal to or higher than the first threshold value. When the shutter speed is equal to or higher than the third threshold value, the field of view of the imaging unit 1 is bright, and when the AGC voltage is equal to or lower than the second threshold value (predetermined gain), or the shutter speed is equal to or lower than the fourth threshold value ( If the AGC voltage is equal to or lower than the second threshold value and the shutter speed is equal to or lower than the fourth threshold value, the field of view of the imaging unit 1 is determined to be dark. If it is determined that the auxiliary illumination 7 is dark, the lighting of the auxiliary lighting 7 is determined (lighting condition is established), and the auxiliary lighting 7 is turned on by the lighting control unit 6 (step 1, hereinafter abbreviated as ST1). The light beam of the auxiliary illumination 7 is reflected by the cover, and the reflected light beam is incident on the imaging unit 1 and the video signal output level is increased (the average luminance of the image is increased). To suppress this, the AGC voltage of the AGC unit 2 is increased. 1 or higher, or the shutter speed by the shutter control unit 3 is higher than the third threshold.
[0011]
As a result, the brightness determination unit 5 determines that the field of view of the imaging unit 1 has become brighter, and this determination satisfies the extinction condition of the auxiliary illumination 7 (ST2: Yes). 7 is turned off (ST3), but the screen from the imaging unit 1 is darkened by this turning off, the lighting condition of the auxiliary lighting 7 is established (ST4: Yes), and the auxiliary lighting 7 is turned on by the lighting control unit 6 (ST5). ) Is repeated (return to ST2). Then, the cover determining unit 8 needs to immediately turn off the auxiliary illumination 7 as described above, and needs to be turned on immediately when the auxiliary illumination 7 is turned off. The field of view of the imaging unit 1 and the auxiliary illumination 7 are both covered. It is determined that this is the case (ST6: Yes), and an alarm is issued from the alarm unit 9 (ST7). Note that the cover determination unit 8 may temporarily emit strong external light or may temporarily block the field of view when the condition for turning off / on is not satisfied immediately after the auxiliary lighting 7 is turned on / off. It is determined that it is not due to cover, but is not due to covering (ST6: No, ST8). Further, when the auxiliary lighting 7 is turned on / off by the lighting control unit 6, when the change in the AGC voltage of the AGC unit 2 is less than a predetermined width, or when the change in the shutter speed by the shutter control unit 3 is less than the predetermined width, the cover is covered. The determination unit 8 determines that at least the imaging unit 1 is covered, and issues a cover alarm.
[0012]
Next, when only the imaging unit 1 is covered (the auxiliary illumination 7 is not covered) and the entire monitoring visual field is dark, the brightness determination unit 5 determines that the visual field is dark, and the bright control unit 6 determines the auxiliary illumination. 7 is turned on, but the entire monitoring visual field is dark, and the light from the auxiliary illumination 7 is covered and blocked, so that the AGC voltage of the AGC unit 2 hardly changes near the lower limit (change is less than a predetermined width). Therefore, the cover determination unit 8 determines that there is a cover based on the determination result of the brightness determination unit 5 and the AGC voltage of the AGC unit 2, and issues an alarm from the alarm unit 9. Further, although the AGC voltage is not near the lower limit, even if the auxiliary illumination 7 is turned on, if the change in the shutter speed by the shutter control unit 3 is not more than a predetermined width, it is determined that the light from the auxiliary illumination 7 is covered and blocked. Therefore, the cover determination unit 8 determines that there is a cover, and issues a warning from the alarm unit 9. When the entire monitoring field is bright, even if the auxiliary illumination 7 is turned on, the incident light quantity of the imaging unit 1 is hardly affected. Therefore, it is difficult to determine whether there is a cover. For example, it is possible to determine whether or not there is a cover by turning off the main illumination.
[0013]
【The invention's effect】
As described above, according to the surveillance camera device of the present invention, the brightness of the field of view of the imaging unit is determined based on whether the AGC voltage is high or low, the shutter speed is fast or slow, and the auxiliary illumination is turned on or off. Whether or not the field of view of the imaging unit of the surveillance camera is covered based on the change in the AGC voltage and the change in the shutter speed at this time, the determination of the brightness of the field of view when the auxiliary lighting is turned on and off, etc. Therefore, the determination is not ambiguous as in the conventional determination based on the output level of the video signal (average luminance of the screen), and the presence or absence of the cover can be determined with high accuracy.
[Brief description of the drawings]
FIG. 1 is a main part block diagram of an embodiment of a surveillance camera device according to the present invention.
FIG. 2 is an explanatory diagram of a control range of an AGC unit and a shutter control unit.
FIG. 3 is a flowchart for explaining the operation of the surveillance camera device according to the present invention;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image pick-up part 2 AGC part 3 Shutter control part 4 Monitor 5 Brightness determination part 6 Illumination control part 7 Auxiliary illumination 8 Cover determination part 9 Alarm part

Claims (7)

A surveillance camera, auxiliary lighting provided in the vicinity of the surveillance camera, and a video signal from the surveillance camera are input, and the AGC (automatic gain control) voltage is varied according to the level change of the video signal to amplify the gain. AGC unit that controls and outputs to the monitor, a shutter control unit that controls the electronic shutter speed of the surveillance camera in accordance with fluctuations in the level of the video signal output from the AGC unit, the AGC voltage of the AGC unit, And / or determining the brightness of the field of view of the monitoring camera based on the shutter speed by the shutter control unit and determining whether to turn on or off the auxiliary illumination based on the determination, and determining the same brightness determination unit a companion to the auxiliary illumination control section for turning on or off of illumination, illumination and extinction of the amount of time a state change of the turning on and off of the auxiliary illumination, or the auxiliary lighting based on Variation of the AGC voltage of the AGC portion or the auxiliary judges covering determining section for determining whether or not a field of view of the monitoring camera is covered from the amount of change in the shutter speed by accompanying the shutter control unit in the turning on and off of illumination And a warning camera device that warns that the visual field of the surveillance camera is covered when it is determined by the cover determination unit that there is a cover. 2. The brightness determination unit according to claim 1, wherein when the AGC voltage of the AGC unit is equal to or higher than a first threshold value, the visual field of the monitoring camera is bright, and when the AGC voltage is equal to or lower than a second threshold value, the brightness determination unit is determined to be dark. Surveillance camera device. The brightness determination unit determines that the visual field of the monitoring camera is bright when the shutter speed by the shutter control unit is equal to or higher than a third threshold value, and is dark when the shutter speed is equal to or lower than the fourth threshold value. Surveillance camera device. The brightness determination unit has a bright field of view of the monitoring camera when the shutter speed by the shutter control unit is greater than or equal to a third threshold, and the brightness of the monitoring camera when the AGC voltage of the AGC unit is less than or equal to a second threshold. The surveillance camera device according to claim 1, wherein the field of view is determined to be dark. When the auxiliary lighting is turned on when the auxiliary lighting is turned on based on the determination of the brightness determining unit, the cover determining unit determines whether the auxiliary lighting is turned off, or for determining the brightness determining unit The surveillance camera device according to claim 1, wherein when the auxiliary illumination is turned off, the brightness determination unit determines whether the auxiliary illumination is turned on when the auxiliary illumination is turned on. When the auxiliary control is turned on / off by the illumination control unit, the cover determination unit has a change in AGC voltage of the AGC unit that is a predetermined width or less, or a change in shutter speed by the shutter control unit is a predetermined width or less. The surveillance camera device according to claim 1, wherein the presence of a cover is determined. The cover determining unit determines that there is a cover when the AGC voltage of the AGC unit is near the lower limit of the control range when the auxiliary lighting is turned on / off by the lighting control unit, and the change in the AGC voltage is less than a predetermined width. The surveillance camera device according to claim 1, comprising:

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