surveillance cameras

Abstract

To efficiently suppress image quality deterioration due to water droplets by removing the water droplets like rain drops adhering to a dome cover.SOLUTION: A monitoring camera comprises: a plurality of camera units which are mounted in the peripheral direction on a device body attached in substantially parallel to a ceiling surface; and a dome cover assembly which has a dome cover that collectively covers the plurality of camera units and is attached to the device body. The dome cover comprises: a water droplet guide surface which includes an axial line of the dome cover, is continuous to an R surface on a virtual surface in parallel to the axial line and is inclined downward as approaching the axial line; and a water droplet reception part which is continuous to the water droplet guide surface. The plurality of camera units have cameras which turn a lens central shaft around a tilt rotation center in the direction vertical to the virtual surface on the virtual surface. The water droplet reception part is provided on the side opposite to the lens central shaft with respect to a field angle boundary on the axial line side in the field angle of the camera in such a state that the camera is inclined to the axial line side at the maximum tilt angle.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to surveillance cameras. [Background technology]

[0002] Patent Document 1 discloses a surveillance camera device that removes dust, water droplets, etc. from a clear dome window, leaving the clear dome window clear and allowing for clear video capture. The surveillance camera device includes a housing main body with at least a built-in surveillance camera, a transparent plastic hemispherical dome-shaped cover attached to one side of the housing main body, a wiper mechanism rotatably attached to the housing main body for cleaning the dome-shaped cover, and a wiper drive unit for driving the wiper mechanism to rotate back and forth. The wiper mechanism includes a silicone rubber wiper blade with an arcuate surface that follows the curved surface of the dome-shaped cover, and a wiper arm with both ends rotatably attached around a central axis parallel to the bottom surface of the dome-shaped cover of the housing main body, with the wiper blade protruding a predetermined length toward the dome-shaped cover. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-126526 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional surveillance camera devices have the problem of high production costs because they are equipped with a wiper mechanism and a wiper drive unit that drives the wiper mechanism to rotate back and forth. Also, when the surveillance camera device is mounted on a ceiling, the height of the device from the ceiling surface, on which the device is mounted, increases due to the wiper mechanism and wiper drive unit, which hinders the device's ability to be made thinner.

[0005] The present disclosure has been devised in consideration of the above-mentioned conventional circumstances, and aims to provide a surveillance camera that can remove water droplets such as rain droplets that adhere to a dome cover and efficiently suppress degradation of image quality due to water droplets. [Means for solving the problem]

[0006] The present disclosure relates to a device body that is attached substantially parallel to a ceiling surface. Nito a dome cover assembly that has a plurality of camera units mounted thereon and a dome cover that collectively covers the plurality of camera units and is attached to the device body; the plurality of camera units are arranged in the circumferential direction of concentric circles centered on the axis of the dome cover, The dome cover includes an axis of the dome cover, and on an imaginary plane parallel to the axis, a water droplet guide surface is formed that is continuous with the R surface and slopes downward as it approaches the axis, and a water droplet receiving portion is formed that is continuous with the water droplet guide surface, and the plurality of camera units have cameras that rotate their lens central axes around a tilt rotation center in a direction perpendicular to the imaginary plane on the imaginary plane, an end portion of the water droplet guide surface that is continuous with the water droplet receiving portion extends toward the axis line side beyond the tilt rotation center of the plurality of camera units; The water droplet receiving portion is The lens central axis is provided on the opposite side of the lens central axis with respect to the boundary of the angle of view of the camera on the axis side when the camera is tilted toward the axis at the maximum tilt angle. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to remove water droplets such as rain droplets adhering to a dome cover and efficiently suppress degradation of image quality due to water droplets. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a surveillance camera according to a first embodiment, viewed obliquely from below; [Figure 2] FIG. 2 is a perspective view of the dome cover assembly shown in FIG. 1; [Figure 3] A side view illustrating the flow direction of water droplets in the surveillance camera shown in Figure 1. [Figure 4] FIG. 4 is a side view illustrating the position of the water droplet receiving portion in the surveillance camera shown in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, with reference to the drawings as appropriate, a detailed description of an embodiment specifically disclosing a surveillance camera according to the present disclosure will be provided. However, more detailed description than necessary may be omitted. For example, detailed description of well-known matters or redundant description of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0010] FIG. 1 is a perspective view of a surveillance camera 11 according to the first embodiment, viewed obliquely from below.

[0011] The surveillance camera 11 according to the first embodiment is installed indoors or outdoors, for example, on a ceiling, under the eaves, etc., and captures images of a monitored object (for example, a person, a vehicle, a motorcycle, etc.). The surveillance camera 11 is a so-called dome-type surveillance camera, and is provided with a dome cover 15 as a protective cover that covers the camera 13. The surveillance camera 11 according to the first embodiment is, for example, a multi-camera in which a plurality of camera units 17 are each collectively covered by a dome cover 15. Note that the number of camera units 17 may be two or more, and is not limited to four as shown in FIG. 1 .

[0012] Surveillance camera 11 is installed by fixing device body 19 to a substantially horizontal ceiling surface 21 (see FIG. 3) with an attachment bracket (not shown) formed from sheet metal in a substantially circular plate shape. Dome cover assembly 23 is fixed to device body 19 with fixing screws (not shown), and is also fixed together with the attachment bracket by fixing screws (not shown) that penetrate device body 19. In other words, device body 19 of surveillance camera 11 is entirely covered by dome cover assembly 23.

[0013] The dome cover assembly 23 has a frame housing 25 formed in an annular shape and attached to the device body 19. The frame housing 25 fixes the outer periphery of the transparent dome cover 15 to the inner hole 27 in a watertight manner.

[0014] Each of the multiple camera units 17 includes one camera 13. Each of the multiple camera units 17 is configured to be able to rotate the camera 13 in a predetermined imaging direction. In other words, each of the multiple camera units 17 is configured so that the user of the surveillance camera 11 can orient the camera 13 in a predetermined imaging direction that the user wants to monitor (capture).

[0015] The device main body 19 includes a plurality of camera units 17 arranged in the circumferential direction of concentric circles centered on an axis 29. The device main body 19 includes a pan base (not shown) that allows each of the plurality of camera units 17 to move freely in the circumferential direction of the concentric circles centered on the axis 29.

[0016] Each of the multiple camera units 17 is supported on a pan chassis base (not shown) and is capable of pan rotation around the axis 29 of the dome cover 15. The camera unit 17 is supported on the pan chassis base so that the pan chassis 31 can twist rotate freely around the twist rotation center in the same direction as the pan direction.

[0017] A tilt hinge 33 is attached to the pan chassis 31. The tilt hinge 33 is supported so as to be tilt rotatable relative to the pan chassis 31 around a tilt rotation center 35 that is perpendicular to the twist rotation center. A camera 13 is attached to the tilt hinge 33. The camera 13 is supported so as to be yaw rotatable relative to the tilt hinge 33 around a lens center axis 37 (see FIG. 4).

[0018] FIG. 2 is a perspective view of the dome cover assembly 23 shown in FIG.

[0019] The dome cover 15 is coated with a hydrophilic coating, which provides excellent visibility during rain and stain resistance. The dome cover 15 is formed in a bowl shape. This bowl shape is a solid of revolution that is point-symmetric about an axis 29.

[0020] The dome cover 15 includes a dome support 39 that protrudes toward the inner periphery of the dome cover 15. The dome support 39 is provided coaxially with the axis 29.

[0021] The dome cover assembly 23 is assembled integrally by combining (covering) with the device body 19 from below with the bowl-shaped inner periphery facing upward (toward the ceiling surface 21 (see FIG. 3)). The dome cover assembly 23 is installed on the ceiling surface 21 by screwing the annular frame housing 25 in the circumferential direction to the device body 19 and the ceiling surface 21 (see FIG. 3) with fixing screws or the like.

[0022] FIG. 3 is a side view illustrating the flow direction of water droplets 41 in the surveillance camera 11 shown in FIG.

[0023] The dome cover 15 has a rounded surface 43 formed between the outer periphery that contacts the frame housing 25 and the axis 29 .

[0024] A water droplet guide surface 45 is connected to the R-surface 43 to guide water droplets 41 adhering to the surface of the dome cover 15 to a water droplet receiving portion 49. The water droplet guide surface 45 is formed on an imaginary plane 47 that includes the axis 29 of the dome cover 15 and is substantially parallel to the axis 29, continuing from the R-surface 43 and sloping downward as it approaches the axis 29. A water droplet receiving portion 49 is further formed continuously on this water droplet guide surface 45, which causes the water droplets 41 guided by the water droplet guide surface 45 to drip below the surveillance camera 11 (in the -Z direction).

[0025] As described above, in the surveillance camera 11 according to the first embodiment, when it rains or the like, the water droplets 41 adhering to the dome cover 15 flow due to gravity from the rounded surface 43 toward the water droplet guiding surface 45. The water droplets 41 that flow onto the water droplet guiding surface 45 flow down along the water droplet guiding surface 45 to the water droplet receiving portion 49 located in a direction approaching the axis 29. The water droplets 41 that flow down and accumulate in the water droplet receiving portion 49 drip below the surveillance camera 11 (in the −Z direction).

[0026] In the first embodiment, dome cover 15 is formed with circular recess 51 that is coaxial with axis 29 and recesses in a direction approaching ceiling surface 21. Therefore, water drip receiving portion 49 is provided in an annular shape radially outward of circular recess 51. Note that circular recess 51 is not an essential component and may be omitted. Note that when circular recess 51 is omitted, water drip receiving portion 49 may be provided on axis 29.

[0027] FIG. 4 is a side view illustrating the position of the water droplet receiving portion 49 in the surveillance camera 11 shown in FIG.

[0028] The camera 13 in each camera unit 17 rotates the lens central axis 37 on the imaginary plane 47 around the tilt rotation center 35 perpendicular to the imaginary plane 47 by the mechanism described above. Each of the cameras 13 shown in FIG. 4 shows a state in which the angle of view of the camera 13 has been tilted to the maximum tilt angle θTmax toward the axis 29 (i.e., approximately the center position of the dome cover 15). Each of the angles of view 53A and 53B indicates the imaging range of each of the two cameras 13 at the maximum tilt angle θTmax. Note that, for ease of understanding, FIG. 4 only shows the angles of view 53A and 53B of two cameras 13, and does not show the angles of view of the other two cameras 13.

[0029] Here, when all the cameras 13 are tilted to the maximum tilt angle θTmax, the water droplet receiving portion 49 is provided outside the angles of view 53A, 53B of all the cameras 13 and on the opposite side of the lens central axis 37 with respect to the angle of view boundary 53 on the axis 29 side of the angles of view 53A, 53B of the cameras 13. As a result, the water droplet receiving portion 49 is outside the field of view of the cameras 13.

[0030] Furthermore, the water droplet receiving portion 49 is formed with an inclination of an included angle θK = 1° to 10° inclined toward the water droplet guide surface 45 and the water droplet receiving portion 49 (i.e., toward the axis 29) with the horizontal plane 55 as the reference (i.e., 0 (zero)°).

[0031] Furthermore, the distance d between the water droplet receiving portion 49 in the direction perpendicular to the axis 29 is set to, for example, 10 mm or more, and the water droplet receiving portion 49 may be shared by multiple cameras 13. Note that if the circular recess 51 is omitted, the water droplet receiving portion 49 may be provided on the axis 29.

[0032] As described above, during rainfall or the like, surveillance camera 11 according to embodiment 1 allows water droplets 41 adhering to dome cover 15 to flow down and drip into water droplet receiver 49 located outside the angle of view of all cameras 13. This allows surveillance camera 11 according to embodiment 1 to more effectively suppress deterioration in the image quality of cameras 13 caused by water droplets 41 remaining within the angle of view of all cameras 13.

[0033] Surveillance camera 11 according to embodiment 1 comprises a device main body 19 attached substantially parallel to ceiling surface 21, a plurality of camera units 17 mounted in the circumferential direction, and a dome cover 15 that collectively covers the plurality of camera units 17, and a dome cover assembly 23 attached to device main body 19. Dome cover 15 includes axis 29 of dome cover 15, and on an imaginary plane 47 parallel to axis 29, water droplet guide surface 45, which is continuous with rounded surface 43 and slopes downward as it approaches axis 29, and water droplet receiving portion 49, which is continuous with water droplet guide surface 45, are formed. The multiple camera units 17 have cameras 13 that rotate their lens central axes 37 around a tilt rotation center 35 in a direction perpendicular to the virtual plane 47 on the virtual plane 47, and the water droplet receiving portion 49 is provided on the opposite side of the lens central axis 37 with respect to the field of view boundary 53 on the axis 29 side of the field of view of the camera 13 when the camera 13 is tilted toward the axis 29 at the maximum tilt angle θTmax.

[0034] In surveillance camera 11 according to embodiment 1, dome cover 15 is formed with water droplet guide surface 45, which includes axis 29, is continuous with rounded surface 43 on imaginary plane 47 parallel to axis 29, and slopes downward as it approaches axis 29, and with water droplet receiving portion 49. Therefore, surveillance camera 11 can cause water droplets 41, such as rainwater, adhering to the side of dome cover assembly 23 or rounded surface 43 of dome cover 15 to flow downward along rounded surface 43 by gravity, reach water droplet guide surface 45 which is continuous with rounded surface 43, and then flow from water droplet guide surface 45 to water droplet receiving portion 49, which is located on the lowest surface of the dome cover surface, where they can drip.

[0035] Specifically, in surveillance camera 11, when cameras 13 are tilted toward axis 29 at maximum tilt angle θTmax, water droplets 41 accumulate in water droplet receiver 49 provided on the opposite side of lens central axis 37 with respect to field of view boundary 53 on the axis 29 side of the field of view of camera 13 in virtual plane 47, and the accumulated water droplets 41 drip downward due to gravity, thereby preventing water droplets 41 from remaining within the field of view of each camera 13. Therefore, surveillance camera 11 according to embodiment 1 can effectively prevent degradation of image quality caused by water droplets 41 appearing in images captured by each camera 13.

[0036] Furthermore, since surveillance camera 11 does not require mechanisms such as a wiper mechanism or wiper drive unit, it is possible to prevent water droplets 41 from appearing in captured images without increasing product costs. Furthermore, since surveillance camera 11 does not require mechanisms such as a wiper mechanism or wiper drive unit, it is possible to prevent the device main body 19 from becoming larger, and since protrusions (such as wiper blades or wiper arms) that protrude from the outer peripheral surface of dome cover 15 are not required, it is possible to prevent the device height from increasing in the Z direction from ceiling surface 21 of surveillance camera 11.

[0037] As described above, in dome cover 15 of surveillance camera 11 according to embodiment 1, circular recess 51 recessed in a direction approaching ceiling surface 21 is formed coaxially around axis 29, and water droplet receiving portion 49 is provided in an annular shape radially outward of circular recess 51. As a result, surveillance camera 11 according to embodiment 1 is formed coaxially around axis 29 of dome cover 15, and circular recess 51 recessed in a direction approaching ceiling surface 21 forms water droplet receiving portion 49 in an annular shape in a plan view radially outward of circular recess 51, so that water droplets 41 flowing down from any direction on dome cover 15 tend to collect in water droplet receiving portion 49. Therefore, water droplets 41 on surveillance camera 11 tend to collect in water droplet receiving portion 49.

[0038] In the first embodiment, when the water droplet receiving portion 49 extends "parallel" from the downwardly sloping water droplet guide surface 45, it has a "bell-shaped" underside with the convex side facing downward. This underside shape can also be said to have the outer circumferential shape of a truncated cone. The water droplet receiving portion 49 may also extend "horizontally" from the downwardly sloping water droplet guide surface 45. In this case, the water droplet receiving portion 49 has, for example, a "flat washer" underside.

[0039] The dome cover 15 is molded from, for example, a polycarbonate resin, which has excellent moldability, transparency, and impact resistance. More specifically, with the bowl-shaped dome opening facing upward, an annular flange portion (not shown) is formed radially outward from the dome opening. A substantially cylindrical straight portion is connected to the flange portion. A substantially spherical rounded surface 43 that gradually approaches the axis 29 is connected to the lower end of the straight portion. The aforementioned water droplet guide surface 45, which slopes downward as it approaches the axis 29, is formed at the lower end of the rounded surface 43. Furthermore, an annular water droplet receiver 49 is connected to the lower end of this water droplet guide surface 45.

[0040] In the dome cover 15, the inside of the annular water droplet receiving portion 49 forms a circular recess 51. In the surveillance camera 11, the water droplet receiving portion 49 and the circular recess 51 are located outside the imaging area of ​​the camera 13. In particular, the circular recess 51 may be made of a non-transparent material, as it has almost no effect on the transmission of imaging light.

[0041] The dome cover 15 can be manufactured by resin molding (such as injection molding) using a mold. Resin molding uses a mold that has a resin injection space (cavity) in the shape of the dome cover, and molten resin is injected into this resin injection space through a gate. In this case, the dome cover 15, which has a shape like a body of revolution, can be manufactured by providing a gate (for example, a direct gate) at the radiation point located on the axis, which reduces the amount of resin used with a simple mold structure and makes it easier to inject the molten resin uniformly in the radial direction, making it easier to obtain a better molded product.

[0042] In such a case, a gate cut mark may remain on the axis of dome cover 15. In dome cover assembly 23, the gate cut mark is positioned inside circular recess 51, and circular recess 51 can be covered with a non-transparent member (for example, dome center cover 57). In this way, surveillance camera 11 can hide the gate cut mark by providing circular recess 51 inside annular water droplet receiving portion 49.

[0043] Furthermore, as described above, the water droplet receiving portion 49 in the surveillance camera 11 according to the first embodiment is shared by multiple cameras 13. As a result, the surveillance camera 11 according to the first embodiment is formed into a substantially circular surface in a plan view, and therefore it is not necessary to provide a corresponding water droplet receiving portion 49 for each camera 13. As a result, even if the surveillance camera 11 is configured so that each of the cameras 13 is movable in the circumferential direction of a circle concentric with the axis 29, the surveillance camera 11 can cause water droplets 41 to flow down from 360° in the circumferential direction of the dome cover 15 toward the water droplet receiving portion 49, and can more effectively suppress the reflection of water droplets 41 in the angle of view of all the cameras 13, regardless of the arrangement of each camera 13 relative to the circumferential direction of the dome cover 15 or the rotation angle of the pan rotation or tilt rotation.

[0044] In a configuration in which the circular recess 51 is omitted, the water droplet receiving portion 49 has a substantially circular surface in plan view, achieving the same effects as those described above. The water droplet receiving portion 49 extends continuously and substantially parallel to the downwardly sloping water droplet guide surface 45, forming an inverted conical side surface with its apex pointing downward (in the -Z direction). The bottom surface of this inverted cone is provided on the opposite side of the lens central axis 37 with respect to the field of view boundary 53 on the axis 29 side of the field of view of the camera 13. In this case, the surveillance camera 11 can provide the water droplet receiving portion 49 shared by multiple cameras 13 in a single location substantially coaxial with the axis 29, allowing the diameter of the dome cover 15 in plan view to be further reduced (particularly the diameter can be made smaller).

[0045] As a result of the above, the angle θK between the water droplet guide surface 45 and the horizontal plane 55 in the surveillance camera 11 according to embodiment 1 is in the range of 1° to 10°. As a result, the surveillance camera 11 according to embodiment 1 has a downwardly sloping lower surface in which the water droplet guide surface 45 forms an angle θK = 1° to 10° with the horizontal plane 55, and can achieve a thin thickness of the surveillance camera 11 in the Z direction while also achieving good downward flow of water droplets 41 outside the angle of view of each camera 13.

[0046] As a result, the water droplet receiving portion 49 in the surveillance camera 11 according to embodiment 1 has a distance d of 10 mm or more in the direction perpendicular to the axis 29. As a result, when the distance d, which is the radial width of the water droplet receiving portion 49, is 10 mm or more, the surveillance camera 11 according to embodiment 1 can prevent the water droplets 41 that have adhered to the water droplet receiving portion 49 due to surface tension from spreading into the angle of view of the camera 13. As a result, the water droplet receiving portion 49 increases the mass of the water droplets 41 that accumulate in the water droplet receiving portion 49 due to surface tension, making it easier for the adhered (accumulated) water droplets 41 to fall, and allowing the accumulated water droplets 41 to fall before they spread into the angle of view of the camera 13.

[0047] Although various embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that those skilled in the art can conceive of various modifications, alterations, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also fall within the technical scope of the present disclosure. Furthermore, the components of the various embodiments described above may be combined in any manner without departing from the spirit of the invention. [Industrial Applicability]

[0048] INDUSTRIAL APPLICABILITY The present disclosure is useful as a surveillance camera that can remove water droplets such as rain droplets adhering to a dome cover and efficiently suppress degradation of image quality due to water droplets. [Explanation of symbols]

[0049] 11. Surveillance Cameras 13 Camera 15 Dome cover 17 Camera Unit 19 Device body 21 Ceiling surface 23 Dome cover assembly 29 axis 35 Tilt rotation center 37 Lens central axis 43 R side 45 Water drop guiding surface 47 Virtual Surface 49 Water drip tray 51 Circular recess 53 Angle of View Boundary 53A, 53B angle of view 55 horizontal plane θK included angle θTmax Maximum tilt angle

Claims

1. a plurality of camera units mounted on a device body attached substantially parallel to a ceiling surface; a dome cover assembly that has a dome cover that collectively covers the plurality of camera units and is attached to the device body; the plurality of camera units are arranged in the circumferential direction of concentric circles centered on the axis of the dome cover, The dome cover includes an axis of the dome cover, and on an imaginary plane parallel to the axis, a water droplet guide surface is formed that is continuous with the R surface and slopes downward as it approaches the axis, and a water droplet receiving portion is formed that is continuous with the water droplet guide surface, the plurality of camera units each include a camera that rotates a lens central axis around a tilt rotation center in a direction perpendicular to the virtual plane, an end portion of the water droplet guide surface that is continuous with the water droplet receiving portion extends toward the axis line side beyond the tilt rotation center of the plurality of camera units; The water droplet receiving portion is provided on the opposite side of the lens central axis with respect to a boundary of an angle of view of the camera on the axis side in a state in which the lens central axis of the camera is tilted toward the axis at a maximum tilt angle. Surveillance camera.

2. The dome cover has a circular recess that is continuous with the drip tray and recesses from the drip tray toward the ceiling surface, and the circular recess is formed coaxially around the axis line, The water droplet receiving portion is provided in an annular shape radially outward of the circular recess. The surveillance camera according to claim 1 .

3. The water droplet receiving portion is shared by a plurality of the cameras. The surveillance camera according to claim 1 .

4. The included angle between the water droplet guide surface and the horizontal plane is in the range of 1° to 10°; The surveillance camera according to any one of claims 1 to 3.

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