JP2021096347A - Imaging device - Google Patents

Abstract

To provide an imaging device which can acquire a high-quality picture in a low-illuminance environment.SOLUTION: The imaging device includes: a housing; a plurality of camera units having imaging means with an imaging element and an optical member; a transparent member arranged to surround an effective light flux range of light entering the imaging element, the transparent member also being located on a side near an object of the camera unit; illumination means for illuminating the object; and a light shielding unit located outside the effective light flux range, the light shielding unit shielding a light flux emitted on the transparent member from the illumination means. The illumination means is arranged in the light shielding unit.SELECTED DRAWING: Figure 2

Description

The present invention relates to an imaging device.

Surveillance cameras are used for crime prevention and disaster prevention in office buildings, shops, and towns. The user selects and installs a camera according to the intended use. If the area you want to monitor, such as the entrance or passage of a building, is decided, a fixed surveillance camera is often installed. On the other hand, if you want to monitor all directions from a bird's-eye view, you may install an omnidirectional camera equipped with a fisheye lens. Furthermore, in recent years, there have been an increasing number of cases in which higher pixel images are monitored without blind spots by using a multi-lens camera in which a plurality of imaging means are housed in one camera. Furthermore, some are equipped with lighting means having a near-infrared wavelength region (hereinafter referred to as IR lighting) so that images can be acquired even in the dark, and the needs for surveillance cameras are diversifying due to the growing needs for surveillance in recent years. It has become.

By the way, in a surveillance camera, a cover for protecting the surveillance camera from an external obstacle or the like may be arranged outside the imaging means. Such a cover is sometimes called a dome, but this dome can cause a deterioration in image quality called a ghost. In response to such a problem, Patent Document 1 proposes a configuration in which the dome is rotated according to the rotation of the imaging means so that the distance from the lens to the dome does not change to reduce the deterioration of the resolution. ing.

Japanese Unexamined Patent Publication No. 2001-45344

However, when IR illumination is used for the surveillance camera of Patent Document 1, ghosts may occur when the near-infrared light emitted from the IR illumination is reflected on the inner surface of the dome and enters the imaging means. Furthermore, when installed outdoors for a long period of time, dirt adheres to the optical surface of the outer peripheral surface of the dome, and the light emitted from the IR illumination is reflected by the dirt attached to the optical surface of the outer peripheral surface of the dome, which also causes ghosting. Can be.

Therefore, an object of the present invention is to provide an imaging device capable of acquiring high-quality images in a low-light environment.

In order to solve the above problems, the present invention is arranged so as to include a housing, a plurality of camera units having an imaging means including an imaging element and an optical member, and an effective luminous flux range of light incident on the imaging element. A transparent member arranged on the subject side of the camera unit, an illumination means for illuminating the subject, and a transparent member provided outside the effective luminous flux range, and the transparent member was irradiated by the illumination means. A light-shielding portion for blocking a light beam is provided, and the lighting means is arranged in the light-shielding portion.

According to the present invention, it is possible to provide an imaging device capable of acquiring high-quality images in a low-light environment.

It is external perspective view of the image pickup apparatus which concerns on 1st Embodiment. It is external perspective view of the image pickup apparatus which concerns on the 1st Embodiment in the state which removed the exterior. It is external perspective view of the image pickup apparatus which concerns on 2nd Embodiment. It is an external perspective view including an operation part. It is external perspective view of the image pickup apparatus which concerns on 2nd Embodiment in the state which removed the exterior.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. At that time, those having the same function in the figure are given the same number, and the repeated description thereof will be omitted. The configuration shown in the following embodiments is only an example, and the present invention is not limited to the illustrated configuration.

(First Embodiment)
The first embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is an external perspective view of the image pickup apparatus 1 according to the first embodiment. The exterior of the image pickup device 1 includes a bottom cover 201, a top cover 202, and a dome 203 for mounting the image pickup device 1 on the ceiling or the like. The dome 203 may be composed of, for example, two parts, a transparent cover (transparent member) 204 made of polycarbonate and a light-shielding cover (first light-shielding member) 205 made of polycarbonate. The transparent cover 204 and the light-shielding cover 205 are integrally molded, and the two parts are molded without a gap. The dome 203 is fixed to the aluminum top cover 202 with screws (not shown). Rubber packing A (not shown) is arranged on the contact surface between the dome 203 and the top cover 202. The top cover 202 is fixed to the bottom cover 201 with screws (not shown). Rubber packing B (not shown) is arranged on the contact surface between the top cover 202 and the bottom cover 201, and the rubber packing A (not shown) and the rubber packing B (not shown) are elastic members, whereby the dome. The sealing inside the 203 is guaranteed. In this embodiment, the bottom cover 201 and the top cover 202 are combined to form a housing.

FIG. 2 is an external perspective view of the image pickup apparatus 1 according to the first embodiment with the exterior removed. Inside the transparent cover 204, as shown in FIG. 2, a camera unit 301 including an image pickup means including an optical component (optical member) such as an optical filter (not shown) and a lens 302 and an image pickup element such as an image pickup sensor 303 is eight. It is arranged on the circumference of each individual. When the exterior is attached, the transparent cover 204 is arranged on the subject side of the camera unit. Further, when the exterior is attached, the transparent cover 204 is arranged so as to include a range through which the effective luminous flux of the light incident on the image pickup sensor 303 passes (effective luminous flux range). The camera unit 301 is rotatably held by engaging the rotation holding portion 305 formed on the base 206 (base portion) with the shaft 304 protruding from the camera unit 301. In the normal state, the camera unit 301 is held by the frictional force between the shaft 304 and the rotation holding portion 305. The camera units 301 are arranged so as to be tilt-rotatable from the horizontal direction to the vertically upward direction about the axis 304, and each camera unit 301 can rotate individually. When the user wants to change the shooting direction of the camera unit 301 when installing the image pickup device 1, the user changes the shooting direction by operating the camera unit 301 with a force equal to or greater than the frictional force between the shaft 304 and the rotation holding unit 305. Can be done.

The transparent cover 204 and the light-shielding cover 205 may be integrally molded as in this embodiment, may be joined by an adhesive or welding, or may be joined by a screw or the like.

By the way, in order to take a picture of a subject in a low illuminance environment such as darkness, a lighting means for illuminating the subject is often required. In general, a method of illuminating a subject using illumination in the near-infrared wavelength region is often used, and an insertable optical filter that transmits only the near-infrared wavelength is inserted in front of the image pickup sensor, for example. The method of acquiring black-and-white video is well known. Since the technique for acquiring such an image is a known technique, the details will be omitted.

Next, in this embodiment, the configuration of the lighting means and the like for acquiring the above-mentioned image will be described. As shown in FIG. 2, eight IR lights 401 are arranged inside the light-shielding cover 205 at substantially intermediate positions of adjacent camera units 301. An opening (not shown) is provided on the surface of the light-shielding cover 205 located on the subject side of the IR illumination 401. Then, the light emitted from the IR illumination 401 passes through the opening (not shown), and further passes through the IR cover 208 as a near-infrared light transmitting member provided on the subject side and is irradiated to the subject side. .. The IR cover 208 is, for example, a translucent member that transmits the light source wavelength of the IR illumination 401. The IR illumination 401 is composed of a near-infrared LED having a near-infrared wavelength region that can be irradiated in an irradiation range that covers the rotation range of the camera unit 301.

By the way, when the light emitted from the IR illumination 401 enters the space in which the camera unit 301 is arranged and reaches the image sensor 303, there is a possibility that image deterioration called ghost occurs in the captured image. Further, when the image pickup apparatus 1 is installed outdoors, there is a high possibility that dirt such as dust and sand adheres to the dome 203 as an optical surface. When the IR illumination 401 is irradiated to the dome 203 with dirt attached to the dome 203, the near-infrared light is reflected by the dirt attached to the dome 203 and the reflected light enters the image pickup sensor 303, causing ghosting. There is a possibility that it will become.

When used for surveillance purposes, it is desirable that the number of ghosts is as small as possible because the desired image cannot be obtained due to the ghosts and it may be difficult to identify the person. In order to reduce the ghost caused by the light emitted from the IR illumination 401, the IR illumination 401 and the space where the camera unit 301 is arranged are optically blocked, and the IR illumination is applied to the dirt adhering to the optical surface. It is desirable not to irradiate the direct light from 401. Further, the occurrence of ghost may be reduced by preventing the stray light from the IR illumination 401 from entering the image pickup sensor 303.

In the present embodiment, a light-shielding plate (second light-shielding member) 207 is provided to block the space where the IR illumination 401 is arranged and the space where the camera unit 301 is arranged. In this embodiment, the IR illumination 401 is arranged on the shading plate 207. The surface extending upward of the light-shielding plate 207 is in contact with the inner surface of the light-shielding cover 205. That is, the IR illumination 401 is arranged in a space surrounded by the light-shielding plate 207, the light-shielding cover 205, and the base 206. Therefore, the light reflected by a part of the light emitted from the IR illumination 401 without passing through the opening (not shown) provided in the light-shielding cover 205 is surrounded by the light-shielding plate 207, the light-shielding cover 205, and the base 206. It will be reflected repeatedly in the space. As a result, the light as described above is only attenuated or radiated to the outside through the opening (not shown) of the light-shielding cover 205 by repeated reflection, and in the space where the camera unit 301 is arranged, It is less likely to enter directly. As a result, the possibility of ghosts that can cause image deterioration is also reduced.

Since the IR illumination 401 may be arranged in a space surrounded by the light-shielding plate 207, the light-shielding cover 205, and the base 206, it may be arranged on the light-shielding cover 205 or the base 206, for example.

Further, since it is sufficient that the space where the IR illumination 401 is arranged and the space where the camera unit 301 is arranged can be blocked, the IR illumination 401 may be arranged outside the dome 203. In this case, for example, a light-shielding cover 205 and a light-shielding plate 207 are provided outside the effective light flux range of the light incident on the image sensor 303, in other words, in a range that does not block the light flux incident on the image sensor 303. Then, the IR illumination 401 is arranged in the light-shielding portion, and the light from the IR illumination 401 with respect to the transparent cover 204 is blocked by the light-shielding portion.

The transparent cover 204 has a curved optical surface, and is formed on a curved surface that follows the tilt rotation locus of the camera unit 301, thereby reducing the deterioration of resolution due to the tilt rotation of the camera unit 301. I'm letting you.

With these configurations, when the subject is irradiated with the IR illumination 401 in the dark and an image is acquired, a high-quality image can be acquired.

In the present embodiment, the tilt operation of the camera unit 301 is manually performed, but it may be electrically tilted. Although the light-shielding plate 207 is provided on the base 206, it may be a light-shielding surface provided on the dome 203. Further, although the illumination means is IR illumination 401 as a near-infrared light source, a wavelength region other than near-infrared may be used for the purpose of photographing a subject.

Further, the arrangement and number of the camera unit 301 and the IR illumination 401 in the present embodiment are merely examples, and are not limited thereto. The number of the camera unit 301 and the IR illumination 401 may be different.

(Second embodiment)
In the first embodiment, in the configuration in which the camera unit 301 and the IR illumination 401 are arranged all around, a configuration for reducing ghosts due to the light emitted from the IR illumination 401 has been described. However, depending on the installation form of the image pickup device, the camera unit 301 and the IR illumination 401 are arranged only in a part of the circumference, and when the image pickup device is installed, the camera unit 301 and the IR illumination 401 are rotated on the circumference. A configuration is also conceivable in which the shooting direction can be changed by allowing the camera to change the shooting direction. For example, when installing near the outer wall of an office building, the direction in which the photograph is desired is often only on the opposite side of the wall. For that purpose, the camera unit 301 does not necessarily have to be arranged all around, and may be arranged, for example, about half a circumference. Further, it is considered desirable that the camera units can be rotated in order to adjust the shooting direction of the camera units arranged about half a circumference. The configuration will be described in detail with reference to FIGS. 3 to 5. The description of the parts that overlap with the first embodiment will be omitted.

FIG. 3 is an external perspective view of the image pickup apparatus 2 according to the second embodiment. The top cover 502 can change its phase with respect to the bottom cover 501 in the rotation direction centered on the central axis 511 of the outer cylindrical surface, and can be fixed with screws (not shown) even at the changed phase position. Has been done. When the user changes the phase of the top cover 502 once fixed and fastened, the fastened screw (not shown) is loosened, and then the operation unit 510 (shown in FIG. 4) provided on the light-shielding cover 505 is gripped. Can rotate.

FIG. 5 is an external perspective view of the image pickup apparatus 2 according to the second embodiment with the exterior removed. Inside the transparent cover 504, as shown in FIG. 5, four camera units 601 as imaging means are arranged on the circumference. The camera units 601 are held so as to be tiltable as in the first embodiment, and each camera unit 601 can individually rotate from the horizontal direction to the vertically upward direction.

The base 506 is rotatably arranged with respect to the bottom cover 501 by a rotation guide portion (not shown) about a substantially central axis 511 of the exterior cylindrical portion.

As shown in FIG. 5, five IR lights 401 are arranged inside the light-shielding cover 505. Specifically, three IR lights 401 are arranged at substantially intermediate positions of adjacent camera units 601 and one is arranged outside each of the two camera units 601 arranged at the ends.

The top cover 502 is provided with a protrusion (not shown) that engages with the oblong hole 605 provided in the base 506. When the top cover 502 is rotated when it is attached to the bottom cover 501, the top cover 502 and the base 506 are caused by the engagement between the protruding portion of the top cover 502 (not shown) and the oval hole (605) of the base 506. It rotates as one.

The rotation of the top cover 502 and the base 506 will be described below while showing specific installation work. As an installation form, installation on the ceiling or installation on the wall via an installation accessory or the like can be considered, but in this embodiment, the work of installing on the ceiling will be described.

When the image pickup device 2 is installed on the ceiling, the work is performed with the top cover 502 integrated with the dome 503 removed as shown in FIG. The bottom cover 501 is fixed to the ceiling with screws (not shown) in the state shown in FIG.

After that, first, the shooting direction of each camera unit 601 is set to a desired direction. Further, each IR illumination 401 is also set in a desired direction.

Next, the top cover 502 integrated with the dome 503 is assembled to the bottom cover 501, and the top cover 502 is integrated with the base 506 in which the four camera units 601 and the five IR lights 401 are arranged. Rotate. That is, the transparent cover 504, the IR illumination 401, the light-shielding cover 505, and the light-shielding plate 207 can be integrally rotated about a rotation axis in a direction substantially perpendicular to the bottom surface of the bottom cover 501. Therefore, the top cover 502 is brought into contact with the bottom cover 501 while the protruding portion (not shown) provided on the top cover 502 is engaged with the oblong hole 605 provided on the base 506. Since the top cover 502 and the bottom cover 501 are slidable in the abutted state, the top cover 502 is placed around the substantially central axis 511 of the exterior cylindrical portion in the state where the top cover 502 is in contact with the bottom cover 501. Rotate to. When rotating, the operation unit 510 provided on the light-shielding cover 505 is rotated while being held by hand, so that the work can be performed without touching the optical surface of the dome 503 with bare hands during the work. Then, the rotation work is performed while checking the image, and when the desired shooting angle is reached, the top cover 502 is fixed to the bottom cover 501 with screws (not shown).

Through these operations, the camera unit 601 can be easily arranged in a desired shooting direction including the tilt direction of the camera unit 601.

Further, the distance from the lens 602 of the camera unit 601 to the optical surface of the dome 503 is substantially the same even when the camera unit 601 is tilted or the four camera units 601 are rotated together. From this, the deterioration of the resolution due to the tilting operation and the rotation of the camera unit 601 is reduced, so that a good image can be acquired regardless of the shooting direction of the camera unit 601.

In the present embodiment, four camera units are arranged on the circumference, but the number of camera units is not limited. Further, although the camera unit 601 and the top cover 502 are manually moved, the effect of the present embodiment can be maintained even if the camera unit is moved electrically.

<Other Embodiments>
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof. For example, a combination of the respective embodiments is also included in the disclosure contents of the present specification.

1, 2, Imaging device 201, 501 Bottom cover 202, 502 Top cover 203, 503 Dome 204, 504 Transparent cover 205, 505 Light-shielding cover 206, 506 Base 207 Light-shielding plate 301, 601 Camera unit

Claims (8)

With the housing
A plurality of camera units having an image pickup means including an image sensor and an optical member,
A transparent member arranged so as to include an effective luminous flux range of light incident on the image sensor and arranged on the subject side of the camera unit.
Lighting means for illuminating the subject and
A light-shielding portion provided outside the effective light flux range and for light-shielding the light flux emitted from the lighting means to the transparent member is provided.
An imaging device characterized in that the lighting means is arranged in the light-shielding portion. The light-shielding portion
A first light-shielding member that is joined or combined with or integrally formed with the transparent member and is arranged on the subject side of the lighting means.
A second light-shielding member arranged between the camera unit and the lighting means is included.
The lighting means is arranged in a space surrounded by the camera unit, a base portion on which the lighting means is arranged, the first light-shielding member, and the second light-shielding member. The imaging device according to claim 1. With the housing
A plurality of camera units having an image pickup means including an image sensor and an optical member,
A transparent member arranged on the subject side of the camera unit and
Lighting means for illuminating the subject and
A second light-shielding member formed by joining or combining with or integrally with the transparent member and arranged on the subject side of the lighting means, and a second light-shielding member arranged between the camera unit and the lighting means. A light-shielding member and a light-shielding portion including the light-shielding member are provided.
The lighting means is arranged in a space surrounded by the camera unit, a base portion on which the lighting means is arranged, the first light-shielding member, and the second light-shielding member. Imaging device. The plurality of camera units can be rotated individually, and regardless of the rotation of the camera unit, the curved surface of the transparent member to which the effective luminous flux is incident and the imaging means of each of the plurality of camera units. The imaging apparatus according to any one of claims 1 to 3, wherein the distances are substantially the same. The transparent member, the lighting means, and the light-shielding portion are integrally rotatable about a rotation axis in a direction substantially perpendicular to the bottom surface of the housing. The imaging apparatus according to any one of 4. The imaging device according to any one of claims 1 to 5, wherein the lighting means includes a light source capable of irradiating light having a near infrared wavelength. The invention according to any one of claims 1 to 6, wherein a translucent member that transmits the light source wavelength of the lighting means is provided on the subject side of the light-shielding portion in which the lighting means is arranged. Imaging device. The imaging device according to any one of claims 1 to 7, wherein an elastic member for sealing is provided between the light-shielding portion and the housing.

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