JP2017156379A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitoring camera having a function for suppressing an image blur and suppressing the expansion of the amplitude of the vibration of an imaging unit, without enlarging a camera body and with a simple configuration.SOLUTION: In an imaging apparatus including the imaging unit comprising at least three parts of a lens barrel, an imaging element, and vibration detection means, image blur correction means, a main body case which stores the imaging unit, a window which is disposed on the front surface of the imaging unit, illumination means which is arranged around the imaging unit, a first light shielding member which is arranged between the window and the imaging unit and whose one end is fixed to the window, and a second light shielding member which is arranged in the backward periphery of the imaging unit and whose one end is fixed to the main body case, the first light shielding member and the second light shielding member comprise a viscoelastic body and the imaging unit includes a regulation member which is supported by the first light shielding member and the second shielding member and arranged around the imaging unit.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image blur suppression function of a surveillance camera.

  In the surveillance camera, there is a problem of “image blur” in which the camera body vibrates due to external vibration and the captured video is shaken.

  In order to suppress image blur, image blur correction means such as an electronic type or an optical type is generally used. Since the existing image shake correction means is a function for correcting low-frequency camera shake caused by hand-held shooting, the correctable vibration is limited to a low frequency.

  On the other hand, in a surveillance camera installed in a structure, high-frequency vibration may also occur due to wind, running vibration of a car, a train, or the like. For this reason, it is difficult for existing image blur correction means to correct high-frequency image blur due to the limit of the frame rate of the image and the limit of the response of the actuator that drives the optical system. Yes.

  In order to solve this problem, Patent Document 1 corrects low-frequency image blur with optical image blur correction built in the imaging unit, and supports the imaging unit with a vibration-isolating support mechanism using a viscoelastic body. A configuration for suppressing high-frequency image blur is cited. Moreover, the vibration damping effect of the vibration isolation support mechanism using a viscoelastic body is shown. Generally, as a characteristic of the viscoelastic body, the amplitude is increased near the resonance frequency, but it is considered that the vibration damping effect described in Patent Document 1 can be obtained by setting the resonance frequency as close to 0 Hz as possible.

  Here, when the configuration of the imaging unit supported by the viscoelastic body is simply replaced with a one-degree-of-freedom vibration system, the resonance frequency is represented by √ (k / m) / 2π. Here, k is the spring constant of the viscoelastic body, and m is the mass of the imaging unit. From the above resonance frequency equation, in order to make the resonance frequency as close as possible to 0 Hz, it is necessary to make the spring constant k of the viscoelastic body close to 0 or make the weight m of the imaging unit close to infinity.

  However, in order to construct it realistically, it is necessary to devise the material and shape of the viscoelastic body in order to support the imaging unit with a viscoelastic body having a low spring constant, or to add a weight to the imaging unit. The problem is that the degree of freedom in design becomes low and the configuration becomes complicated.

  To deal with this problem, Patent Document 2 is configured to increase the amplitude at a low frequency, but there is a method of suppressing the amplitude increase with a simple configuration in which the periphery of the lens is supported by a shock absorber.

Japanese Patent No. 5761843 JP 2010-204293 A

  However, in the prior art disclosed in Patent Document 1 and Patent Document 2 described above, a new mechanism needs to be added in order to suppress image blur, and thus there is a problem that the camera body becomes large. In addition, even if image shake is suppressed with the configuration described in Patent Document 1 or Patent Document 2 described above, in a surveillance camera with built-in illumination, if the illumination is on the camera body, the illumination light may be shaken by the vibration of the camera body. This is a problem.

  Therefore, an object of the present invention is to provide a surveillance camera having a function of suppressing image blur and suppressing the amplitude of vibration of an imaging unit from being enlarged with a simple configuration without increasing the size of the camera body. It is to provide.

In order to achieve the above object, an imaging apparatus according to the present invention includes:
An imaging unit comprising at least three points of a lens barrel, an imaging element, and vibration detection means for detecting vibration applied to the lens barrel;
An image blur correction unit that corrects an image blur using the vibration detected by the vibration detection unit;
A main body case for storing the imaging unit;
A transparent window disposed in front of the imaging unit;
Illumination means disposed around the imaging unit;
A first light-shielding member disposed between the window and the imaging unit in a cylindrical shape, one end of which is fixed to the window;
In the imaging apparatus having a second light-shielding member disposed around the rear of the imaging unit and having one end fixed to the main body case,
The first light shielding member and the second light shielding member are made of a viscoelastic body, and the imaging unit is supported by the first light shielding member and the second light shielding member and arranged around the imaging unit. It is characterized by having a regulating member.

  According to the present invention, there is provided a surveillance camera capable of suppressing an increase in amplitude even when the amplitude is increased by suppressing image blur without increasing the size of the camera body and with a simple configuration. be able to.

1 is an external view of a surveillance camera according to a first embodiment of the present invention. 1 is an exploded perspective view of a surveillance camera according to a first embodiment of the present invention. It is sectional drawing of the surveillance camera by the 1st Example of this invention. It is a conceptual diagram of the light-shielding principle of the 1st light-shielding member by the 1st Example of this invention. It is a figure which shows the vibration damping effect by 1st Example of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[Example 1]
Hereinafter, the image blur correction function of the surveillance camera according to the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is an external view of a surveillance camera according to a first embodiment of the present invention.

  A main body case 101, a window frame 102, and a transparent window 103 disposed in front of the imaging unit 201 are configured. The window 103 is fixed to the window frame 102 by means such as adhesion.

  FIG. 2 is an exploded perspective view showing the configuration of the surveillance camera according to the first embodiment of the present invention.

  Inside the main body case 101, an imaging unit 201, an LED 202 as an illumination unit, a first light shielding member 203, a second light shielding member 204, and a regulating member 205 are housed. Here, electronic image blur correction, which is an image blur correction unit in the present embodiment, will be described.

  First, the imaging unit 201 has at least a lens barrel, an imaging element, and a gyro sensor. The image entered from the lens barrel is formed on the image sensor, and a partial area of the image sensor is extracted and output as an image. Further, the direction and amount of shake applied to the monitoring camera are detected by the gyro sensor. Then, an image in which the image blur correction is corrected is output by moving the region in the image sensor in the direction opposite to the direction of the shake detected by the gyro sensor.

FIG. 3 is a sectional view of the surveillance camera according to the first embodiment of the present invention.
Around the front of the image pickup unit 201, a plurality of LEDs 202 as illumination means are attached to the image pickup unit 201 via a support member. In addition, a cylindrical first light shielding member 203 is disposed so as to surround the entire circumference of the front surface of the imaging unit 201, and one end of the first light shielding member 203 is fixed to the inside of the window 103 by means such as adhesion. Has been.

  Here, the light shielding principle of the first light shielding member 203 in the present invention will be described with reference to FIG. FIG. 4 is a schematic view showing the light shielding principle of the first light shielding member in the present invention.

  Light rays from the LEDs 202 arranged around the imaging unit 201 are reflected within the thickness of the window 103. The reflected light beam is blocked by the first light blocking member 203 in contact with the window. This prevents light from entering the lens barrel. Here, as shown in FIG. 4, the light from the LED 202 is incident from the outer edge of the first light shielding member 203 at a constant irradiation angle θ, and the reflected light is shielded by the inner edge. Then, the thickness x in the circumferential direction of the first light shielding member necessary for light shielding is x ≧ 2t · tan (θ / 2) from the irradiation angle θ of the light beam emitted from the LED and the plate thickness t of the window. Become.

  In FIG. 4, the LED 202 is disposed at a position close to the circumferential direction of the imaging unit 201 for convenience, but it goes without saying that the light shielding effect is not affected even if the LED 202 is disposed outside.

  A cylindrical second light-shielding member 204 is disposed so as to surround the entire circumference around the rear of the imaging unit 201, and one end of the second light-shielding member 204 is fixed to the inside of the main body case 101 by means such as adhesion. Has been. The light beam from the LED 202 is diffusely reflected in the main body case 101 and enters through the gap in the imaging unit 201 to affect the image. By shielding the gap in the imaging unit 201 inside the second light shielding member 204, the influence on the image is prevented.

  In the present embodiment, the first light shielding member 203 and the second light shielding member 204 are formed of viscoelastic bodies and have a vibration damping function. The imaging unit 201 is supported so as to be sandwiched between the first light shielding member 203 and the second light shielding member 204. In this embodiment, the maximum frequency that can be corrected by electronic image blur correction is 1 to 30 Hz. Therefore, the vibration system including the imaging unit 201, the first light shielding member 203, and the second light shielding member 204 is configured to have a vibration damping effect at 30 Hz or more.

  Moreover, as shown in FIG. 3, the 1st light shielding member 203 and the 2nd light shielding member 204 are members of the substantially identical shape comprised with the same material. Thereby, the number of parts can be reduced and it can contribute to cost reduction. In addition, the position of the center of gravity G of the imaging unit is adjusted so that a load is evenly applied to the front first light shielding member 203 and the rear second light shielding member 204. With this configuration, the optical axis A of the imaging unit 201 can move substantially parallel to the vibration from the main body case 101.

  A regulating member 205 is disposed so as to surround the imaging unit 201. In the present embodiment, when the image pickup unit 201 is stationary, the regulating member 205 does not contact the image pickup unit 201 on the entire circumference and has a clearance L. This clearance L is determined by the magnitude of the amplitude that can be corrected by electronic image blur correction.

  The outer periphery of the regulating member 205 is fixed to the inside of the main body case 101 by bonding or the like. Alternatively, a member integrated with the main body case 101 may be used. Further, in order to relieve an impact when the imaging unit 201 comes into contact with the regulating member 205, a portion where the regulating member 205 comes into contact with the imaging unit 201 or the whole regulating member 205 may be formed of a viscoelastic body. In this case, the regulating member 205 may be in contact with the imaging unit 201 when the imaging unit 201 is stationary, but the viscoelastic body is elastic by the clearance L when the vibration is applied. It shall be comprised so that it may deform | transform.

  Desirably, the regulating member 205 is arranged on a line that is substantially perpendicular to the optical axis A of the imaging unit 201 and passes through the vicinity of the center of gravity G of the imaging unit 201 as shown in FIG. With this configuration, even if the imaging unit 201 is regulated by the regulating member 205, the optical axis A of the imaging unit 201 can be maintained substantially parallel.

Here, the vibration suppressing effect of the present invention will be described.
FIG. 5 is a graph showing an example of the vibration attenuation effect by the first light shielding member 203 and the second light shielding member 204 in the present embodiment. The vibration response ratio for each excitation frequency is shown. The vibration response ratio is a ratio of the amplitude of vibration of the imaging unit 201 to the amplitude of vibration applied to the main body case 101.

  As shown in FIG. 5, at a low frequency, the amplitude is expanded due to the influence of resonance, and the amplitude response ratio at 1 Hz is about 1.15 at about 1.00, 5 Hz, and about 1.47 at 10.87 Hz. The maximum vibration response ratio. From 18 Hz or higher, the higher the frequency, the more attenuated, and the frequency is about 1.00 at 18 Hz, about 0.50 at 30 Hz, about 0.27 at 50 Hz, and about 0.19 at 70 Hz.

  In this embodiment, when the vibration frequency is within a frequency range that can be corrected by electronic image blur correction, the imaging unit is affected by the viscoelastic body of the first light shielding member 203 and the second light shielding member 204. The amplitude increases. However, since the vibration of the photographing unit 201 is suppressed within the clearance L by the restricting member 205, it can be corrected by electronic image blur correction.

  If the frequency to be excited is greater than or equal to the frequency range that can be corrected by the electronic image blur correction, the electronic image blur correction does not function, but the vibration of the imaging unit 201 is attenuated by the vibration damping effect of the viscoelastic body. , Image blur is suppressed.

  With the above configuration, it is possible to provide a monitoring camera that corrects image blur in a wide range of frequencies with a simple configuration without increasing the size.

  In this embodiment, the LED 202 is attached to the photographing unit 201. Since this is a configuration for maintaining the positional relationship between the imaging unit 201 and the LED 202 and preventing shake of illumination, of course, even if it is fixed to the main body case 101 or the window frame 102 other than the imaging unit 201, the vibration damping effect Needless to say, it has no effect.

101 body case, 103 window, 201 imaging unit, 202 LED,
203 1st light shielding member, 204 2nd light shielding member, 205 Restriction member

Claims (4)

An imaging unit comprising at least three points of a lens barrel, an imaging element, and vibration detection means for detecting vibration applied to the lens barrel;
An image blur correction unit that corrects an image blur using the vibration detected by the vibration detection unit;
A main body case for storing the imaging unit;
A transparent window disposed in front of the imaging unit;
Illumination means disposed around the imaging unit;
A first light-shielding member disposed between the window and the imaging unit in a cylindrical shape, one end of which is fixed to the window;
In the imaging apparatus having a second light-shielding member disposed around the rear of the imaging unit and having one end fixed to the main body case,
The first light shielding member and the second light shielding member are formed of viscoelastic bodies, and the imaging unit is supported by the first light shielding member and the second light shielding member,
An imaging apparatus comprising a regulating member disposed around the imaging unit. The imaging apparatus according to claim 1, wherein the first light shielding member and the second light shielding member have the same shape. The imaging device according to claim 1, wherein the restricting member is disposed at a position that is perpendicular to the optical axis of the imaging unit and that passes through the vicinity of the center of gravity of the imaging unit. The imaging apparatus according to claim 1, wherein the illumination unit is attached to the imaging unit.