JP2011211557A - Monitoring camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitoring camera which improves the reliability of a method of detecting interference by comparing the luminance value of the image of a monitoring area and illuminance.SOLUTION: The monitoring camera 1a includes: an imaging element 7 provided in a housing 5; an illuminance sensor 11 provided inside the light-receiving part 12a of the housing, and detecting the illuminance; and an interference determination unit 15 for determining the interference when the luminance value of the image of the imaging element is equal to or lower than a predetermined value and the illuminance of the illuminance sensor is equal to or higher than a predetermined value. Since the light-receiving part is formed in the housing so that light from the front which is in an imaging direction and light from the upper direction different from it are both made to be incident, inconsistency arises between the luminance value and the illuminance when the front of the imaging element is widely covered. Thus, the occurrence of the interference is accurately determined and the reliability as the monitoring camera is improved.

Description

  The present invention relates to a surveillance camera for monitoring and recording a suspicious person's behavior installed in a place where a person such as a store or a company is frequently coming and going, and in particular, a surveillance camera having a high reliability for detecting a disturbing action. It is about.

  2. Description of the Related Art Conventionally, a surveillance camera system that can install a surveillance camera in a desired surveillance location such as in a store and display a captured image on a monitor for monitoring, or record image data for use as a subsequent evidence Is widely known.

  In such a surveillance camera system, for example, there is a possibility that a fraudulent person may commit a crime after covering the imaging lens of the camera with a hand or covering it so that it cannot be imaged. A person has applied for a patent according to Patent Document 1.

  In Patent Document 1, an illuminance sensor that detects the illuminance of the monitoring area is provided in the monitoring camera or in a place away from the monitoring camera, and the image is captured even though the illuminance is equal to or higher than a predetermined value (that is, bright). There is described a surveillance camera system that determines that there has been an obstruction such as closing a lens when the luminance value of an image is below a predetermined value (that is, dark).

JP 2001-218189 A

  As in the invention described in Patent Document 1, when comparing the luminance value of the image in the monitoring area and the illuminance, the point of what illuminance is detected by the illuminance sensor greatly affects the reliability of the determination result. For example, when an illuminance sensor is provided at a location away from the monitoring camera and the illuminance is detected in an area completely different from the imaging range captured by the imaging unit in the monitoring area, the imaging range is turned off and the image is displayed. When the whole changes darkly, even if it is a regular action, the luminance value of the image and the illuminance do not match, and there is a possibility that it is erroneously determined that an obstructing action such as blocking the lens has occurred.

  For this reason, the illuminance detected by the illuminance sensor is preferably matched to the imaging range of the imaging unit, but in this case, another problem may occur. For example, if the imaging unit and the illuminance sensor are arranged on the front surface of the camera housing so that the imaging unit and the illuminance sensor receive light in the same field or direction in the monitoring area, even if the front of the monitoring camera is widely covered, If there is no inconsistency between the measured values of the two, there is a possibility that the disturbing action cannot be accurately detected.

The applicant has conducted various experiments on detection of disturbing actions with respect to conventional surveillance cameras, and as a result of earnest research, has found the above-described problems.
The present invention has been made in view of the above problems, and provides a surveillance camera that improves the reliability of a technique for detecting a disturbing action by comparing the luminance value of an image obtained by imaging a surveillance area with the illuminance of the surveillance area. The purpose is to do.

  The surveillance camera of the present invention is provided in a housing as a main body, an imaging unit provided in the housing for imaging a monitoring area in a predetermined imaging direction, a light receiving unit provided in the housing, and a light receiving unit. An illuminance detection unit that detects the illuminance of the monitoring area, and when the luminance value of the image captured by the imaging unit is equal to or less than a predetermined value and the illuminance detected by the illuminance detection unit is equal to or greater than the predetermined value, there is an interference act. An interference determining unit that determines that the light receiving unit is configured to receive both light from the imaging direction of the imaging unit and light from a direction different from the imaging direction of the imaging unit. It is characterized by being composed.

  According to the present invention, the interference determination unit is configured such that, in an image composed of a plurality of divided regions captured by the imaging unit, the number of divided regions having a luminance value equal to or smaller than a predetermined value is predetermined with respect to the number of image regions of the entire image. When the ratio is equal to or greater than the ratio, the luminance value of the image captured by the imaging unit may be determined to be equal to or less than a predetermined value.

  According to the present invention, the light receiving unit includes a light receiving window formed continuously across the first surface on which the imaging unit is provided on the outer surface of the housing and the second surface adjacent to the first surface. It can be configured.

  According to the present invention, the light receiving section is formed on the first surface on which the imaging section is provided on the outer surface of the housing and on one or more other surfaces adjacent to the first surface. The light receiving window can be provided.

  According to the present invention, the light-receiving unit includes a first surface on the outer surface of the housing on which the imaging unit is provided, two light-receiving windows formed on the other surface serving as the back surface of the first surface, A light guide path that guides light from the light receiving window to the illuminance detection unit may be provided.

  According to the present invention, the illuminance detection unit is installed in the light receiving unit such that the light receiving surface is in the same direction as the imaging direction of the imaging unit, and the light receiving unit is inserted into the light receiving unit from a direction different from the imaging direction. It is possible to provide a guide means for guiding the light incident on the light receiving surface of the illuminance detection unit as light in the same direction as the imaging direction of the imaging unit.

  According to the surveillance camera of the present invention, the light receiving unit provided with the illuminance detection unit has a structure in which both light from the imaging direction of the imaging unit and light from a direction different from the imaging direction can enter the light receiving unit. Therefore, the brightness value of the image captured by the imaging unit and the illuminance detected by the illuminance detection unit are unlikely to be inconsistent when the imaging range becomes dark overall due to extinction or the like. There is less risk of misjudgment that sabotage has occurred. On the other hand, when the front of the imaging unit is widely covered, etc., there is a mismatch between the luminance value of the image captured by the imaging unit and the illuminance detected by the illuminance detection unit, and thus an obstruction act has occurred. The possibility of being able to accurately perform the determination is increased, and the reliability as a surveillance camera is improved.

  According to the present invention, in an image composed of a plurality of divided areas captured by the imaging unit, the occurrence of interference occurs when the number of divided areas having a luminance value equal to or less than a predetermined value is equal to or greater than a predetermined ratio with respect to the total number of divided areas. Since the determination is performed, it is possible to perform a more appropriate determination in accordance with the actual situation by appropriately determining the determination reference value such as the luminance value and the number of divisions based on an experiment or the like that simulates an actual situation.

  According to the present invention, the light receiving unit extends from the surface of the housing where the image capturing unit is provided to another surface adjacent thereto so that light from the imaging direction and other directions can enter the light receiving unit. The light receiving windows can be formed continuously.

  Further, according to the present invention, the light receiving unit is provided on the surface of the housing where the image capturing unit is provided and the other surface adjacent thereto so that light from the imaging direction and other directions can enter the light receiving unit. A plurality of light receiving windows can be formed respectively.

  According to the present invention, the light receiving unit receives light on the surface on which the image capturing unit of the housing is provided and the other surface on the back of the surface so that light from the image capturing direction and other directions can enter the light receiving unit. A window can be formed, and a light guide path can be provided from each light receiving window to the illuminance detection unit to guide light.

  According to the present invention, the illuminance detection unit is installed in the light receiving unit in the same direction as the imaging direction so that light from the imaging direction and other directions can enter the light receiving unit. Guiding means may be provided so that light incident on the light receiving unit from a direction different from the imaging direction is guided by the guiding unit and reaches the illuminance detecting unit as light in the same direction as the imaging direction.

It is a figure which shows the installation condition of the surveillance camera which concerns on embodiment of this invention. 1 is an overall configuration diagram of a surveillance camera system according to an embodiment of the present invention. It is a perspective view of the surveillance camera which concerns on embodiment of this invention. It is an expanded sectional view of the light-receiving part of the surveillance camera concerning the embodiment of the present invention. It is a flowchart which shows the interference determination procedure in the interference determination part of the surveillance camera system which concerns on embodiment of this invention. It is a functional block diagram which shows the structure of the image recording device which is a part of the surveillance camera system which concerns on embodiment of this invention. It is a perspective view of the surveillance camera which concerns on 2nd Embodiment of this invention. It is a perspective view of the surveillance camera which concerns on 3rd Embodiment of this invention. It is a perspective view of the surveillance camera which concerns on 4th Embodiment of this invention. It is a perspective view of the surveillance camera which concerns on 5th Embodiment of this invention.

1. 1st Embodiment (FIGS. 1-6)
A surveillance camera 1a according to the first embodiment and a surveillance camera system including the surveillance camera 1a will be described with reference to FIGS.

(1) Overall Configuration As shown in FIG. 1, in the surveillance camera system of this embodiment, a surveillance camera 1a is installed on a ceiling C or the like in a room R of a store or a company, and a surveillance area in the room R The image captured by the monitoring camera 1a is monitored by an image recording apparatus or the like (described later) installed at another location and recorded as necessary. Although FIG. 1 shows one monitoring camera 1a provided in one room R, the number of monitoring cameras 1a included in the monitoring camera system is not limited as will be described later.

  As shown in FIG. 2, the surveillance camera system of the present embodiment records one or more surveillance cameras 1a that are installed in a surveillance area and photograph the area, and image data captured by the surveillance camera 1a. Therefore, the image recording apparatus 2 installed at a location different from the monitoring camera 1a is connected by the LAN 3. The network connecting the monitoring camera 1a and the image recording apparatus 2 is not limited to the LAN 3, and a wide area network such as the Internet network or ISDN network may be used. The image recording apparatus 2 is connected to an external device such as a display 4 (image display means) such as an LCD that can be used for displaying an image in a monitoring area as an external device.

(2) Surveillance camera 1a
The surveillance camera 1a is means for digitally encoding images taken at each installation location and transmitting image data to the image recording device 2 via the LAN 3.

  As shown in FIG. 2, the monitoring camera 1 a includes an optical system 6 that captures an image of a monitoring area outside the housing 5 in a substantially rectangular parallelepiped housing 5 that is a main body, and a predetermined image obtained by the optical system 6. An image pickup unit including an image pickup element 7 that converts the signal into a signal and outputs the signal is provided. As shown in FIG. 3, the optical system 6 of the imaging unit is attached to the front surface 5 a so as to protrude toward the front imaging direction on the outer surface of the substantially rectangular parallelepiped housing 5.

  As shown in FIG. 2, the housing 5 further includes an image analog / digital converter 8 that converts an analog image signal sent from the image sensor 7 of the imaging unit into a digital signal, and an image analog / digital converter 8. An image compression circuit 9 that generates and outputs compression-encoded data (image data) by compressing the above signal, and a communication unit 10 that transmits the image data from the image compression circuit 9 to the image recording apparatus 2 via the LAN 3. It has. Note that all surveillance cameras 1a are assigned camera numbers for individually identifying each surveillance camera 1a, and are stored in a storage unit (not shown) provided in any part of the circuit configuration of each surveillance camera 1a. The camera number of each surveillance camera 1a is stored in advance.

  In the surveillance camera 1a, the image signal output from the image sensor 7 is converted into a digital signal by the image analog / digital converter 8 at the shooting interval stored as shooting information, and the digital signal is further stored in the image quality stored as shooting information. Are compressed by the image compression circuit 9 according to the parameters corresponding to the above, and compressed encoded data (image data) is generated.

  In this embodiment, a method based on the JPEG2000 standard is adopted as the image compression encoding method, but other standards such as the JPEG standard and the MPEG2 Video standard may be used. In addition, cameras of different image compression encoding methods may be mixed on the LAN 3, or the image compression encoding method of the monitoring camera 1a may be switched.

  The generated image data is transmitted from the communication unit 10 to the image recording apparatus 2 via the LAN 3. The image data transmitted at this time includes the above-described camera number. Note that a microphone (not shown) may be provided in the monitoring camera 1a, and an audio signal input from the microphone may be compression-coded in the monitoring area, multiplexed with image data, output to the LAN 3, and transmitted to the image recording apparatus 2. Good.

  Next, as shown in FIG. 2, the monitoring camera 1 a has an illuminance sensor 11 in the housing 5 as illuminance detection means for detecting the illuminance of the monitoring area outside the housing 5. The illuminance sensor 11 receives light from the outside via a light receiving portion 12 formed in the housing 5 of the monitoring camera 1a.

  As shown in FIG. 3, the light receiving portion 12a is formed at the corner between the front surface 5a to which the optical system 6 of the imaging unit is attached and the upper surface 5b continuous with the front surface 5a on the outer surface of the substantially rectangular parallelepiped housing 5. Further, at the same angle portion, the optical system 6 is disposed at the right position when viewed from the front. The light receiving portion 12 a includes a light receiving window 13 that is a slit-like opening formed continuously between the front surface 5 a and the upper surface 5 b of the housing 5. Therefore, the light receiving unit 12a transmits light from the monitoring area on the front surface 5a side, which is the imaging direction of the image sensor 7, and light from above on the upper surface 5b side, which is different from the imaging direction, through the light receiving window 13. It can be taken into the light receiving part 12a.

  As shown in FIGS. 3 and 4, an illuminance sensor 11 is provided inside the light receiving portion 12 a formed in the housing 5. The illuminance sensor 11 is arranged with its light receiving surface 30 facing forward, and can directly receive light from the monitoring area on the front surface 5a side, which is the imaging direction of the image sensor 7. Although not shown in FIG. 3, as shown in detail in FIG. 4, the light incident on the light receiving unit 12 a from the upper direction different from the imaging direction is inside the light receiving unit 12 a. A reflecting mirror 14 is provided as a guiding means for reflecting and guiding incident light so as to reach the light receiving surface 30 of the illuminance sensor 11 from substantially the same direction as the imaging direction. The reflection mirror 14 of the present example is configured by arranging two reflection mirrors 14 and 14 in a posture inclined at 45 degrees in the same direction with the reflection surfaces facing the upper side and the lower side at a predetermined interval from the light incident side. The light that is a member of a set and that is incident from directly above is not in the same direction as the imaging direction of the image sensor 7, but can reach the light receiving surface 30 of the illuminance sensor 11 as light from obliquely upward and forward near this. it can. Therefore, according to the light receiving unit 12a, even if the light receiving capability of the illuminance sensor 11 has some directivity, the light from the imaging direction of the imaging element 7 that hits the light receiving surface 30 from the front and the light are perpendicular to each other. Both light from above can be detected properly. That is, according to the embodiment of the present invention, light that is incident on the light receiving unit 12a from a direction different from the imaging direction reaches the light receiving surface 30 as light from the same direction as the imaging direction. As the degree of conversion or guidance, the light from the same direction can reach the light receiving surface 30 to such an extent that the illuminance can be properly measured in view of the object of the invention. In addition to the reflection mirror 14 described above, for example, a guide unit may be configured using a prism, a half mirror, a light guide plate, or the like.

  In the present embodiment, the illuminance sensor 11 is arranged in the light receiving unit 12a so that the light receiving surface 30 faces the front, and the reflection mirror 14 is provided in the light receiving unit 12a so that light from above is directed to the light receiving surface 30 side. However, the illuminance sensor 11 is arranged in the light receiving portion 12a so that the light receiving surface 30 faces the direction of 45 degrees obliquely forward, and both the light from the front and the light from above are received under the same conditions. It may be incident on the surface 30. In this case, guide means such as the reflection mirror 14 are not necessary.

  Next, as shown in FIG. 2, the monitoring camera 1 a further includes an interference determination unit 15 that determines whether or not an interference act exists. The disturbance determination unit 15 calculates the luminance value of the image data, and based on the luminance value and the detection result of the illuminance sensor 11, whether or not an obstructing action is performed so as to block the optical system 6 and make imaging impossible. It is a means to determine.

With reference to the flowchart shown in FIG. 5 and FIG. 2, the determination procedure of the obstruction act by the obstruction determination part 15 demonstrated briefly above is demonstrated.
First, the power of each part of the surveillance camera system is turned on. Each monitoring camera 1 a of the system captures an image of the monitoring area with the image sensor 7 and outputs an image signal to the interference determination unit 15. The interference determination unit 15 captures image signals from the image sensor 7 at predetermined time intervals in step S1. In step S2, for each frame image obtained, the brightness value of each pixel constituting the image is calculated (256 levels in terms of brightness gradation), and the averaging process is performed to obtain the average brightness value of the entire image. calculate. In step 3, the calculated average brightness value of the entire image is compared with a predetermined brightness value set in advance. This is a step of determining whether the entire image of the monitoring area is dark or bright on the basis of a certain standard, and when the predetermined luminance value is larger than the average luminance value of the entire image (YES in step 3). In this case, the monitoring area is dark, and the process proceeds to Step 4. In step 4, for each of the plurality of divided regions constituting one frame, the luminance values of the plurality of pixels included in each divided region are averaged to calculate the average luminance value of the divided region. In step S5, the number of divided areas having a predetermined luminance value or less is calculated among the plurality of divided areas for which the average luminance value is calculated. The predetermined luminance value used here may be the same as or different from the luminance value used in step 3. In step 6, the number of divided areas having a predetermined luminance value or less is compared with a predetermined value m. This is a step of determining whether or not there are many dark portions in the image of the monitoring area on the basis of a certain standard. When the number of divided areas equal to or less than a predetermined luminance value is larger than a predetermined value m (step) No. 6 is a case where there are many dark portions in the image of the monitoring area, and the process proceeds to Step 7. In step 7, the illuminance detected by the illuminance sensor 11 is compared with a predetermined value, and if the illuminance detected by the illuminance sensor 11 is equal to or greater than the predetermined value (YES in step 7), When the monitoring area of the image sensor 7 is darker than the predetermined reference, the monitoring area of the illuminance sensor 11 is brighter than the predetermined reference. An abnormal signal is output. While the power is on, the determination by the above steps is repeated and the detection of the disturbing action is continued.

  As described above, in the interference determination unit 15, when the entire monitor area screen is dark (YES in step 3) and there are many dark areas in the monitor area screen (YES in step 6), the monitor area screen is displayed. In this case, the illuminance detected by the illuminance sensor 11 that is a detection target not only in the detection direction by the image sensor 7 but also in the other direction is compared with the reference, and the illuminance is equal to or greater than a certain standard. In the case, it is determined that there was an obstruction.

  As illustrated in FIG. 2, when the interference determination unit 15 determines that there is an interference act, the interference determination unit 15 outputs the determination result and information used for the determination as an abnormal signal, and from the communication unit 10 together with information on the camera number of the monitoring camera 1a. The data is sent to the image recording apparatus 2 via the LAN 3.

(3) Image recording device 2
The image recording apparatus 2 shown in FIG. 2 and FIG. 6 records image data and abnormal signals received from the monitoring camera 1a, and informs a warning when abnormal information such as disturbing actions is received from the monitoring camera 1a. Output.

  As illustrated in FIG. 6, the image recording apparatus 2 includes a communication unit 16, an external device connection unit 17, a notification unit 18, an operation unit 19, a storage unit 20, and a control unit 21.

  As shown in FIG. 6, the control unit 21 includes a recording processing unit 22, a display control unit 23, and a notification control unit 24. The communication unit 16 is a communication I / F connected to the LAN 3. The image recording apparatus 2 is connected to the monitoring camera 1a and a monitoring center (not shown) via the LAN 3 by the communication unit 16.

  The external device connection unit 17 is connected to the display 4 such as the LCD described above as a monitoring device.

  The notification unit 18 includes a light emitting unit such as an LED and / or a sounding unit such as a buzzer, and performs notification with light or sound when abnormal information such as an obstruction is received from the monitoring camera 1a. In addition, it is good also as a structure which abbreviate | omits the alerting | reporting part 18 by making monitoring means, such as the display 4 mentioned above connected to the external apparatus connection part 17, function as an alerting | reporting part.

  The operation unit 19 includes a plurality of buttons and the like, and is operated by a user to input setting information such as an image recording schedule.

  The storage unit 20 is a storage medium such as a ROM / RAM, a hard disk drive (HDD), or a DVD-R. The storage unit 20 records image data 25 that is controlled by the recording processing unit 22 and received from the monitoring camera 1a, and abnormality information 26 based on an abnormality signal.

  The recording processing unit 22 of the control unit 21 sequentially records the image data 25 received for each monitoring camera 1 a together with the camera number and the current time in the storage unit 20 based on the setting information set by the operation unit 19. When an abnormal signal is received from the monitoring camera 1a, various information included in the abnormal signal is recorded as abnormal information 26 in the storage unit 20 in association with the camera number and the current time.

  The display control unit 23 of the control unit 21 decompresses the image data 25 received from the monitoring camera 1a, and displays it on the display 4 that is an external device from the external device connection unit 17. In addition, when the abnormality determination is made by the recording processing unit 22, the display control unit 23 superimposes and displays the abnormality display on the display 4 together with the image determined to be abnormal. Even if the front of the optical system 6 of the image pickup means is covered by the image plan and the image by the image pickup device 7 becomes dark, it is the same as the screen when the light is turned off or the like simply by darkening the screen of the display 4. Therefore, it cannot be judged that it is abnormal by itself. Therefore, when there is an abnormality determination, the display control unit 23 displays, for example, characters such as “abnormality due to shielding of the imaging unit” on the screen of the darkened display 4 and displays the monitoring area. 4 indicates that the dark screen is due to an abnormality.

  When the notification control unit 24 of the control unit 21 receives an abnormal signal from the monitoring camera 1a, the notification control unit 24 causes the notification unit 18 to notify and output the abnormality. At this time, an alarm signal may be output to a center device provided in a remote monitoring center.

2. Other embodiments (FIGS. 7 to 10)
Monitoring cameras 1b to 7e according to other embodiments having different structures of the light receiving unit 12 will be described with reference to FIGS.

  First, in the monitoring camera 1b shown in FIG. 7, the light receiving unit 12b that houses the illuminance sensor 11 includes a front surface 5a from which the optical system 6 of the imaging unit protrudes on the outer surface of the housing 5, and an upper surface 5b adjacent to the front surface 5a. And a circular light receiving window 33 formed independently of each other. Each light receiving window 33 is opened on the surface of the housing 5, and the inside of the housing 5 in which each light receiving window 33 is opened is a cavity having the same shape as the slit-shaped light receiving portion 12 in the first embodiment shown in FIG. It has become. And the illuminance sensor 11 is arrange | positioned in the position where the centerline of each circular light reception window 33 cross | intersects inside the cavity of the light-receiving part 12b. Although the illuminance sensor 11 has the light receiving surface 30 facing the light receiving window 33 on the front surface 5a, the light incident from the light receiving window 33 on the upper surface 5b sufficiently reaches the light receiving surface 30 of the illuminance sensor 11 and measures the illuminance. Can do. Alternatively, a light guiding member as shown in FIG. 4 is provided inside the cavity of the light receiving portion 12b, and the light incident from the light receiving window 33 on the upper surface 5b is substantially equivalent to the light from the light receiving window 33 on the front surface 5a. It may be configured to reach the light receiving surface 30 of the illuminance sensor 11 under certain conditions.

  Next, in the monitoring camera 1c shown in FIG. 8, the light receiving unit 12c that houses the illuminance sensor 11 includes a front surface 5a from which the optical system 6 of the imaging unit projects on the outer surface of the housing 5, and one of the adjacent front surfaces 5a. The side surface 5c (the right side as viewed from the line of sight facing the optical system 6) is provided with a circular light receiving window 33 formed independently. Each light receiving window 33 is an opening to the outside of a through hole formed inside the housing 5, and each through hole communicates within the housing 5 to constitute a light receiving portion 12 c. And the illuminance sensor 11 is arrange | positioned in the cross | intersection part of both through-holes. Although the illuminance sensor 11 has the light receiving surface 30 facing the light receiving window 33 on the front surface 5a, the light incident from the side light receiving window 33 can reach the light receiving surface 30 of the illuminance sensor 11 sufficiently to measure the illuminance. it can. Alternatively, a light guide member is provided inside the light receiving unit 12 so that light incident from the light receiving window 33 on the side surface is incident on the light receiving surface 30 of the illuminance sensor 11 under substantially the same conditions as the light from the light receiving window 33 on the front surface 5a. It may be configured to reach.

  Next, in the monitoring camera 1d shown in FIG. 9, the light receiving unit 12d that houses the illuminance sensor 11 includes a front surface 5a from which the optical system 6 of the imaging unit protrudes on the outer surface of the housing 5, and an upper surface 5b adjacent to the front surface 5a. And three circular light receiving windows 33 formed independently on one side surface 5c (on the right side when viewed from the line of sight facing the optical system 6). Each light receiving window 33 is an opening to the outside of three through holes respectively formed in the housing 5, and each through hole communicates at one intersection in the housing 5 to form a light receiving portion 5 d. is doing. The illuminance sensor 11 is disposed at the intersection of the three through holes. The illuminance sensor 11 has the light receiving surface 30 facing the light receiving window 33 on the front surface 5a. However, light incident from the light receiving windows 33 on the upper surface 5b and the side surface 5c sufficiently reaches the light receiving surface 30 of the illuminance sensor 11 to increase the illuminance. Can be measured. Alternatively, a light guide member is provided inside the light receiving portion 12d, and light incident from the light receiving windows 33 on the upper surface 5b and the side surface 5c is substantially the same as the light from the light receiving window 33 on the front surface 5a. You may comprise so that the light-receiving surface 30 may be reached.

  Next, in the monitoring camera 1e shown in FIG. 10, the light receiving unit 12e that houses the illuminance sensor 11 includes a front surface 5a from which the optical system 6 of the imaging unit protrudes on the outer surface of the housing 5, and a rear surface with respect to the front surface 5a. Two rear light receiving windows 33 formed independently are provided on the rear surface 5d. The light receiving window 33 on the front surface 5a is an opening of a through hole formed inside the housing 5, and the illuminance sensor 11 is disposed inside the through hole with the light receiving surface 30 facing upward. The light receiving window 33 on the rear surface and the through hole are connected by a light guide path 35 made of an optical fiber, a light guide plate, or the like for guiding light from the light receiving window 33 on the rear surface to the illuminance sensor 11. Similarly, a light guide path may be formed for the light receiving window 33 and the through hole on the front surface 5a. In the present embodiment, the light receiving surface 30 of the illuminance sensor 11 faces upward not facing any light receiving window 33, but light incident from the light receiving windows 33 on the front surface 5 a and the rear surface 5 d is the light receiving surface 30 of the illuminance sensor 11. It is possible to measure the illuminance by sufficiently reaching

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c, 1d, 1e ... Surveillance camera 2 ... Image recording device 5 ... Housing 5a ... Front surface of housing 5b ... Upper surface of housing 5c ... Side surface of housing 5d ... Rear surface of housing 6 ... Optics constituting imaging means System 7 ... Imaging device constituting imaging means 11 ... Illuminance sensor as illuminance detection means 12a, 12b, 12c, 12d, 12e ... Light receiving part 13, 33 ... Light receiving window 14 ... Reflecting mirror 15 as guide means 15 ... Interference determining part 30 ... Light receiving surface of illuminance sensor 31 ... Light guide path

Claims (6)

A housing;
An imaging unit provided in the housing for imaging a monitoring area in a predetermined imaging direction;
A light receiving portion provided in the housing;
An illuminance detection unit that is provided in the light receiving unit and detects the illuminance of the monitoring region;
A disturbance determining unit that determines that there is an obstruction when the luminance value of an image captured by the imaging unit is a predetermined value or less and the illuminance detected by the illuminance detection unit is a predetermined value or more;
The monitoring camera, wherein the light receiving unit is configured such that light from an imaging direction of the imaging unit and light from a direction different from the imaging direction of the imaging unit are incident on the light receiving unit. In the image including a plurality of divided regions picked up by the image pickup unit, the interference determination unit is configured such that the number of divided regions having a luminance value equal to or smaller than a predetermined value is equal to or greater than a predetermined ratio with respect to the number of divided regions in the entire image. The monitoring camera according to claim 1, wherein the luminance value of the image captured by the imaging unit is determined to be equal to or less than a predetermined value. 3. The light receiving portion according to claim 1, wherein the light receiving portion includes a light receiving window formed continuously across a first surface on which the imaging portion is provided on an outer surface of the housing and a second surface adjacent to the first surface. The described surveillance camera. The light receiving portion includes a first surface on the outer surface of the housing on which the imaging portion is provided and a plurality of light receiving windows formed independently on one or more other surfaces adjacent to the first surface. Item 3. The surveillance camera according to item 1 or 2. The light receiving unit includes two light receiving windows formed on a first surface on which the imaging unit is provided on the outer surface of the housing, another surface serving as a back surface of the first surface, and the illuminance detection from each light receiving window. The surveillance camera according to claim 1, further comprising a light guide that guides light to a portion. The illuminance detection unit is installed in the light receiving unit such that the light receiving surface thereof is in the same direction as the imaging direction of the imaging unit,
Guide means is provided in the light receiving unit for guiding light incident on the light receiving unit from a direction different from the imaging direction to reach the light receiving surface as light from a direction equivalent to the imaging direction of the imaging unit. The surveillance camera according to any one of claims 1 to 5.

Images