JP5268607B2 - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To always provide an excellent shot image even when an original focal length of an imaging optical system is displaced in imaging an object when an imaging device is removably installed in a dome type protective case. <P>SOLUTION: The imaging device 103 mountable and removable in/from a hemispherical dome type protective case 102 includes: a mounting means 108 to detachably mount the imaging device in the dome type protective case 102 along with the imaging optical system 107; and a focal length information change means 109 to change the focal length information of the imaging optical system when the imaging device is mounted in the dome type protective case 102. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a photographing apparatus that can be detachably mounted in a hemispherical dome-shaped protective case, for example, suitable as a surveillance camera.

  2. Description of the Related Art Conventionally, an imaging device used in an installation type such as a monitoring camera device is installed inside a hemispherical dome shape that covers the imaging device. There are several types of dome shapes.

  FIG. 8A shows a surveillance camera in which a photographing device 72 is arranged in a transparent clear dome 71. FIG. 8B shows a surveillance camera in which a photographing device 74 is arranged in a smoke dome 73 with a colored dome.

  The clear dome shown in FIG. 8A is used to protect the photographing apparatus from rainwater, for example. The smoke dome shown in FIG. 8B is used for the purpose of preventing a peep from the outside and making it difficult to understand the presence and orientation of the photographing apparatus.

Various types of surveillance cameras in which the photographing device is housed in the dome are proposed (Patent Documents 1 to 3).
JP 2001-45344 A JP 2000-209471 A JP 2004-104242 A

  Surveillance cameras in which a photographic device is housed inside a dome shape have the characteristics that durability against environmental changes is improved, and a wide range of surveillance can be performed if the camera can be rotated. Further, the hemispherical dome has a feature that installation space is small and installation is easy.

  On the other hand, when the photographing apparatus is installed in the dome, the focal length of the photographing optical system used in the photographing apparatus changes.

  In general, a dome has a hemispherical outer shape, and the outer portion performs a negative lens action. If the dome at this time is miniaturized, the radius of curvature of the hemispherical surface of the outer portion (hereinafter referred to as R) becomes smaller. Along with this, the focal length of the photographing optical system shifts to a shorter one, and the photographing magnification is lowered. This means that the specification as a photographing device changes depending on the type of dome installed.

  When the focal length of the photographing optical system changes, for example, the following problems occur.

(B) The shooting angle of view differs from the actual angle of view. (B) The stored focus trajectory shape changes in the rear focus type zoom lens, and focus fluctuation occurs when zooming is performed. When the image side has an anti-vibration optical system, the correction amount for anti-vibration of the anti-vibration lens is determined by the focal length of the entire system, so the generation amount for anti-vibration fluctuates and the optical performance deteriorates The present invention has an object of providing an imaging device that, when installed in a dome-shaped protective case so as to be detachable, can always obtain a good captured image even when the original focal length of the imaging optical system changes during imaging. To do.

The photographing apparatus of the present invention is a photographing apparatus that is detachable in a hemispherical dome-shaped protective case , and includes a photographing optical system , mounting means that is detachably mounted in the dome-shaped protective case , and the dome-shaped protective case . A change that changes a movement locus for focusing on a predetermined object distance corresponding to the focal length information of the photographing optical system when mounted in a case, corresponding to the zooming movement of the photographing optical system. And means .

  According to the present invention, when it is detachably installed in a dome-shaped protective case, an imaging device that can always obtain a good captured image even when the original focal length of the imaging optical system changes during imaging can be obtained.

  Embodiments of the photographing apparatus of the present invention will be described below.

  The photographing apparatus of the present invention is detachably mounted in a hemispherical dome-shaped protective case.

  The photographing apparatus has a photographing optical system such as a photographing lens or a zoom lens having a single focal length.

FIG. 1 is a schematic diagram of Embodiment 1 of the present invention. In the embodiment of FIG. 1, the photographing apparatus 103 having the photographing optical system 107 is installed in a hemispherical dome (clear dome) (dome-shaped protective case) 102 and used as the monitoring camera 101.

  The photographing apparatus 103 is installed on a support base 105 through a shaft 104 so that panning and tilting are possible. Reference numeral 106 denotes a base.

  The photographing apparatus 103 is provided with attachment means 108 that is detachably attached to the dome-shaped protective case 102. And when the imaging device 103 is mounted in the dome-shaped protective case 102, it has a focal length information changing means 109 for changing the focal length information of the imaging optical system 107.

  Here, the focal length information changing unit 109 drives the lens element in the optical axis direction by vibration or remote operation manually by the switching unit 110 provided in the photographing apparatus 103.

  The photographing apparatus 103 is provided with a detecting means (automatic attachment detecting means) 111 for automatically detecting whether or not the photographing apparatus 103 is attached in the dome-shaped protective case 102.

  The detecting means 111 detects the dome shape such as the curvature and thickness of the surface of the dome-shaped protective case 102, the distance from the photographing optical system 107 to the dome 102, and the like.

  The focal length information changing unit 109 changes the focal length information of the photographing optical system 107 based on a signal from the automatic mounting detecting unit (detecting unit) 111.

  For example, the focal length information of the photographing optical system is changed in various ranges depending on the shape of the dome 102. For example, the focal length of the entire system is changed by changing the amount of movement of the lens element.

  FIG. 2 is a schematic diagram of a main part of a part of the photographing apparatus 103 of the present invention. FIG. 3 is an explanatory diagram showing the relationship between the photographing optical system 1 and the dome 102.

2 and 3, reference numeral 1 denotes a photographing optical system, which includes a four-group rear focus zoom lens (hereinafter referred to as "RFZ lens") including four lens groups. The RFZ lens 1 includes a fixed first lens unit L1, a second lens unit L2 having a variable power function, a fixed third lens unit L3 composed of an afocal system, a focus function, and an image plane associated with variable power. The fourth lens unit L4 has a function of correcting the fluctuation.

  In FIG. 3, 1 is a photographing optical system, and 102 is a dome. G is a glass block such as a filter or a face plate. IP is an image plane on which a solid-state image sensor such as a CCD is disposed.

  The photographing optical system 1 includes a zoom lens that performs focusing by a part of the zoom unit or a lens unit on the image side of the zoom unit.

  Actually, each lens group is composed of a plurality of lenses, but the number of lenses constituting each lens group is not particularly limited.

  Reference numeral 2 denotes a photoelectric conversion element such as a CCD. Reference numeral 3 denotes a diaphragm member for adjusting the amount of light incident on the photoelectric conversion element 2. Reference numeral 4 denotes a diaphragm driving unit that drives the aperture of the diaphragm member 3 with a signal from the control unit 7 so that the amount of light incident on the photoelectric conversion element 2 is constant.

  Reference numeral 5 denotes an aperture position detecting means for detecting the aperture (aperture value) of the aperture member 3. Reference numeral 6 denotes a detection circuit that detects the output from the aperture position detection means 5 and outputs it to the control means 7.

  Reference numerals 8 and 9 denote driving means such as step motors for driving the second and fourth lens groups L2 and L4, respectively. Reference numerals 10 and 11 denote drivers for driving the driving means 8 and 9.

  An amplifier 12 amplifies the output from the photoelectric conversion element 2. A process circuit 13 generates an AF signal (auto focus detection signal) for converting the signal into a signal such as an NTSC video signal and performing AF (auto focus operation). Reference numeral 14 denotes an AF means for performing an AF operation by an AF signal from the process circuit 13. Note that any AF method may be used. For example, a method known as a hill climbing method (Japanese Patent Laid-Open No. Sho 62-103616) can be applied.

  Reference numeral 15 denotes detection means for detecting the presence or absence of the dome and the shape of the dome. Reference numeral 16 denotes a dome setting means (fixing means), which is composed of a member used when setting the photographing apparatus to a dome.

  In this embodiment, the control means (focal length information changing means) 7 detects the presence / absence of a dome sent from the detection means 15 and the optical axis direction of the lens portion of the photographing optical system stored in the storage means in advance. The focal length information corresponding to the position is changed or corrected.

  FIG. 4 shows a flow of operation in the control means 7 at this time. Start in step S200.

  In step S201, the presence / absence of a dome is detected. If there is a dome, focal length information in the case of having a dome is obtained and output in step S202. When there is no dome in step S202, the focus information when there is no dome is obtained in step S203. For example, the focal length data for the presence / absence of the dome may be stored in advance in the storage means as the storage information, and the storage information may be determined based on the storage information.

  Further, the focal length information of either the presence or absence of a dome is previously stored. For example, when a state where a dome is present is detected, and a state where the dome is not present is detected, it may be obtained from a predetermined calculation. Alternatively, correction may be performed with a correction coefficient, and the method for obtaining focal length information based on the presence or absence of a dome is not particularly limited. Then, the process ends in step S204.

  FIG. 5 is an explanatory diagram of the in-focus position (optical axis direction) of the fourth lens unit L4 for each subject distance at each focal length when zooming is performed in the zoom lens having the configuration shown in FIG. is there.

That is, it is the trajectory information of the fourth lens unit L4 stored in the storage unit in the control unit 7 when performing the zooming operation while keeping the image plane position constant.

In FIG. 5, curves a, c, and b indicate the movement trajectory of the fourth lens unit L4 during zooming when focusing on an object at infinity, an object at an intermediate distance, and an object at a close distance in order.

  In the present embodiment, the movement locus of the fourth lens unit L4 is stored in the storage means in some form (the locus itself or a function with the lens position as a variable).

  The trajectory information is read according to the position of the second lens unit L2 for zooming on the optical axis, and the fourth lens unit L4 is moved based on the information.

  In the locus following operation shown in FIG. 5, the points a0, a1, a2,... A11 and the points b0, b1, b2,. It is a trajectory. Points c0, c1, c2,..., C11 are trajectories calculated by the following formula based on the two representative trajectories a0 to a11 and b0 to b11 at an arbitrary intermediate distance.

c (n + 1) = | c (n) −a (n) | / | b (n) −a (n) |
× | b (n + 1) −a (n + 1) | + a (n + 1) (1)
According to the equation (1), for example, in FIG. 5, when the fourth lens unit L4 is at the point c0, the ratio of the internal division from the point c0 to the line segment b0-a0 is obtained. Then, the zoom position Z is obtained from the position of the second lens group 102 on the optical axis. When the zoom position is Z1, the point c1 is a position on the optical axis of the fourth lens unit L4 that internally divides the line segment b1-a1 according to this ratio.

  For example, the internal ratio is calculated as follows.

α: Internal ratio numerator β: Internal ratio denominator α = c0−a0
β = b0−a0
c1 = a1 + (b1-a1) × (α / β)
Thus, the position on the optical axis of the fourth lens unit L4 when the subject distance position of the point c0 is zoomed in focus is the point c1.

A position (zoom position) Z on the optical axis of the second lens unit L2 is obtained by a position sensor. When the zoom position Z is obtained, the movement locus (curve C) of the fourth lens unit L4 at each zoom position is obtained using the internal ratio described above.

For example, an example in which the number of stored trajectories is 8 (trajectory numbers 0 to 7 in the figure) is shown.

Assume that the current focus position of the fourth lens unit L4 is Fpos and the zoom position is Zpos.

  When the focus preset storage operation is performed at this position, the movement locus used for the fourth lens unit L4 and the internal division ratio described above are stored. Thus, the stored subject distance position of the focus preset is set.

  An example is shown below. If the current zoom position Z is on the zoom position having the storage locus data described above, the internal ratio can be obtained by the above-described calculation. Here, it is assumed that the zoom position Zpos is not stored data of the trajectory but is between the zoom positions Zpos0 and Zpos1 having the stored trajectory data.

  In order to obtain the internal ratio at the current zoom position Z, the following calculation is performed. The closest locus position FposA at the current zoom position Z and the infinite locus position FposB at the current zoom position are approximately obtained from the stored locus data. Here, a calculation example obtained by linear approximation will be described.

  In terms of numerical values, zooming is larger on the tele side and smaller on the wide side. In addition, the focus is assumed to be large on the near side and small on the infinite side.

Zpos: Current zoom position Fpos: Current focus position FposA: Nearest locus position at the current zoom position FposB: Infinite locus position at the current zoom position Zpos0: Tele zoom position with storage locus data Zpos1: With storage locus data Wide-side zoom position FposA0: Nearest memory trajectory position at Zpos0 FposA1: Nearest memory trajectory position at Zpos1 FposB0: Infinite memory trajectory position at Zpos0 FposB1: Infinite memory trajectory position at Zpos1 α: Internal ratio numerator β: Internal division Specific denominator FposA = FposA0 + (FposA1-FposA0) ×
(Zpos-Zpos1) / (Zpos0-Zpos1)
FposB = FposB0 + (FposB1−FposB0) ×
(Zpos-Zpos1) / (Zpos0-Zpos1)
α = Fpos-FposA
β = FposB-FposA
The trajectory number used in the calculation is the selection number of the trajectory used from the current focus position and zoom position. For example, in the above example, No. 1 and No. 2 are used. In this case, as the stored data, not only the internal ratio but also information for identifying which storage trajectory used for calculation is selected and used is required. In the above example, since the first or second of the trajectory is used, any information that can determine whether the first or second is used as the stored data may be used. For example, “No. 1 and No. 2” are stored as stored data, or “No. 1” is stored in advance, so that “No. 1” and “No. 2” are used in advance for calculation. If it can be identified, the trajectory data to be stored is not particularly limited.
The following is an example of stored data.

TrackData: locus number data TrackData = 1
α = 100
β = 300
These data are stored in a memory (storage means) when a preset storing operation is performed.

FIG. 6 is a diagram showing that the following locus of the fourth lens unit L4 changes when focusing on an infinite subject depending on the presence or absence of a dome. As can be seen from this figure, the fourth lens unit L4, for example, takes a trace trace obtained from the calculation described above when a dome is mounted. Also, when zooming is performed using the trajectory information with a dome when there is no dome, the shape of the movement trajectory is different, so the image plane position cannot be made constant and the focus is blurred.

  Therefore, in this embodiment, the movement locus accompanying zooming of the fourth lens unit L4 is changed depending on the presence or absence of the dome. This prevents the image plane position (focus position) from changing during zooming. The current zoom position and focus preset are obtained from the trajectory number, the internal ratio numerator α, and the internal ratio denominator β stored by the storage operation.

  Based on the following calculation.

Zpos: current zoom position FposTarget: preset focus position (position on the optical axis of the fourth lens unit L4 )
FposTarget A: Nearest locus position obtained from the storage locus number at the current zoom position Z FposTargetB: Infinite locus position Zpos0 obtained from the storage locus number at the current zoom position Z Wide-side zoom position FposTarget A0: Storage locus position FposTarget A1 obtained from the closest-side storage locus number at the tele-side zoom position Zpos0: Storage locus position FposTargetB0 obtained from the nearest-side storage locus number at the wide-side zoom position Zpos1 From the infinite-side storage locus number at Zpos0 Obtained memory trajectory position FposTargetB1: Memory trajectory position obtained from infinite memory trajectory number in Zpos1 α: internal ratio numerator β: internal ratio denominator FposTarget etA = FposTargetA0 + (FposTargetA1−FposTargetA0) × (Zpos−Zpos1) / (Zpos0−Zpos1)
FposTargetB = FposTargetB0 + (FposTargetB1-FposTargetB0) × (Zpos−Zpos1) / (Zpos0−Zpos1)
FposTarget = FposTargetB +
(FposTargetA-FposTargetB) × (α / β)
When the zoom operation is performed with the dome mounted, driving from the current focus position to the preset focus position FposTarget may be performed. Then, the subject distance position when stored can be reproduced even if the zoom position is changed.

  Next, FIG. 7 shows a flow.

  In step S701, it is determined whether or not there is a focus preset storage operation. If an operation has been performed, the trajectory number and internal ratio are stored from the current focus and zoom position in step S702, and the process proceeds to step S703. If there is no storage operation in step S701, the process proceeds to step S703. In step S703, it is determined whether or not there is an effective operation.

  If there is an operation, the presence / absence of stored information is determined in step S704, and if there is, a preset position is calculated from the zoom position and stored information in step S705. In step S706, it is compared whether or not the current focus position is a preset position. If it is not the preset position, the focus lens (fourth lens group) is driven in step S707, and the process returns to step S706 to drive until the preset position is reached. If there is no storage position in step S704, the process returns to step S701.

  If there is no effective scanning in step S703, the process returns to step S701.

  As described above, the focus preset position is changed by changing the zoom position. By using the selection trajectory number and the internal division ratio as preset storage information so as to keep the subject distance position, it is possible to enable the focus preset function even in the rear focus type lens configuration in the entire zoom range.

  Further, as can be seen from the locus of the rear focus lens, it can be seen that the locus is concentrated on the wide side, but dispersed on the tele side.

  The focus preset is stored at the zoom position A, and then the second lens group L2 is driven in the wide direction in the manual focus mode without adjusting the focus to the zoom position B. When the focus preset storage operation is performed and then the zoom position A is restored to the original zoom position A, the stored position is shifted.

  This is because the resolution of the subject distance is coarser than the zoom position A at the zoom position B on the wide side. For example, if the internal ratios α and β are 115 and 300 when the zoom position A is set to the wide zoom position B and the preset storage is performed again, it becomes 1 and 3. For this reason, when the zoom position is returned to the original position, the calculation is performed from the internal ratio of 1 and 3. For this reason, α calculates the subject distance position corresponding to 1: 3 to 100 as the preset position with respect to 115 with respect to β300, so that the difference between 115 and 100 appears as the difference between the stored subject positions.

  Accordingly, when the preset is stored in the manual focus state and the focus preset is stored when zooming to the wide side in the manual focus mode without performing the focus adjustment, the following operation is performed. That is, it is only necessary not to update the focus preset storage information.

  From the above description, according to the present embodiment, the rear focus type zoom lens is equivalent to the fact that the focus preset is not stored with the zoom operation. Even if it is stored, there is a restriction that it must be canceled by a zoom operation, so that the problem that the focus preset function in the rear focus lens cannot be realized in practice can be solved. Because of these problems, it is possible to incorporate a focus preset function that could not be done because it is a rear focus type zoom lens.

Schematic diagram of Example 1 of the present invention Schematic diagram of essential parts of Embodiment 1 of the present invention 1 is an enlarged explanatory view of a part of FIG. Flowchart of Embodiment 1 of the present invention Explanatory drawing of the focus of the photographing optical system according to the present invention FIG. 4 is an explanatory diagram of a cam locus of a lens unit in zooming with and without a dome in Embodiment 1 of the present invention. Flow chart of the first embodiment Illustration of a conventional dome-shaped camera

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Surveillance camera 102 Dome 103 Imaging device 104 Axis 105 Support stand 106 Base 107 Imaging optical system 108 Mounting device 109 Focal length information change means 110 Switching means 111 Detection means

Claims (5)

A photographic device detachable in a hemispherical dome-shaped protective case,
Photographic optics ,
Mounting means for detachably mounting in the dome-shaped protective case;
When mounted in the dome-shaped protective case , a movement locus for zooming of the photographing optical system, and a movement locus for focusing on a predetermined subject distance corresponding to the focal length information of the photographing optical system Change means to change,
A photographing apparatus comprising:   The photographing apparatus according to claim 1, wherein the focal length information changing unit is driven by vibration or remote operation by a switching unit provided in the photographing apparatus. The photographing apparatus includes a detecting unit that detects whether or not the dome-shaped protective case is mounted, and the focal length information changing unit is configured to perform zooming of the photographing optical system based on a signal from the detecting unit. The photographing apparatus according to claim 1 or 2, wherein the accompanying movement locus is changed. The photographing apparatus has detection means for detecting whether or not the dome-shaped protective case is mounted, and the detecting means detects a dome shape of the dome-shaped protective case to which the photographing apparatus is mounted; 4. The focal length information changing unit changes a movement trajectory associated with zooming of the photographing optical system based on a signal from the detection unit. Shooting device.   5. The photographing apparatus according to claim 1, wherein the photographing optical system includes a zoom lens that performs focusing by a part of the zoom unit or a lens unit on the image side of the zoom unit.