JP4428734B2 - Imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus such as a video camera having a vibration isolation (also referred to as vibration isolation or vibration suppression) function.
[0002]
[Prior art]
In recent video cameras, cameras with an anti-vibration function in which camera shake prevention means are mounted are common. There are optical correction and electronic correction as methods of the camera shake prevention function.
[0003]
In optical camera shake correction, a prism or lens member capable of optical axis displacement is arranged in the middle of the optical path of photographing light incident on an image sensor, and the optical axis is displaced according to camera shake, thereby performing camera shake correction. As a camera shake detection means used in the optical system, it is common to detect angular components of the camera by detecting the vibration component directly applied to the camera using an angular velocity sensor such as a vibration gyro and integrating the output. It has become.
[0004]
On the other hand, electronic image stabilization is often used in combination with a motion vector detection method that calculates the amount of motion of a camera from a change in video signal between fields and uses it as a shake signal. The stored image is corrected by extracting a part of the memory image so that the motion is removed.
[0005]
In addition, as another system for electronic camera shake correction, a sensor is used for camera shake detection, and only part of the image received by the image sensor is cut out, and the camera shake correction is performed by controlling the cutout position according to the detected camera shake. There are also types that do this.
[0006]
In the case of the electronic system, since the video signal is electrically corrected, the correction period is a field period, and hand shake during the exposure time cannot be removed, but there is an advantage that it can be made smaller and lighter than the optical system. Further, by using a high-density large-sized image pickup device, the resolution of a captured image extracted or extracted from a memory is increased, and image quality degradation, which is disadvantageous compared to the optical type, is being improved.
[0007]
[Problems to be solved by the invention]
However, in the above-described conventional camera shake correction means, regardless of the method, the object to be removed is camera shake (frequency is about 3 Hz to 8 Hz), and there is a correction effect even when considering on-vehicle etc. It was up to about 20 Hz, and it was not possible to prevent vibrations at frequencies higher than that. In the case of a video camera, it is merely a “camera shake correction function”, not a “anti-vibration function” that can remove any vibration transmitted to the camera. In particular, in the case of an electronic system, the correction cycle is a field cycle, so unless it is a frequency less than ½ of the field cycle (30 Hz or less for NTSC), in principle, it cannot be corrected, and bridge girders such as pedestrian bridges, In a shooting scene where the vibration frequency is high when the camera is installed on a tripod or on a ship, there is no anti-vibration effect or, depending on the response characteristics of the correction system, there is a phase delay, There was a problem of doing.
[0008]
Further, in the case of electronic image stabilization, there is a problem that the correction effect for large shaking is lower than that of optical image stabilization and the correction range is small. In principle, the smaller the ratio of the size of the extracted image to the entire captured image, the more the shake can be corrected. However, the smaller the extracted image, the smaller the number of pixels, and the smaller the captured image is post-processed. This is because the image quality is greatly deteriorated due to the necessity of electronic enlargement processing and the like, and therefore priority is given to the image quality at the expense of the image stabilization effect.
[0009]
The present invention has been made under such circumstances. In order to bring the image stabilization function closer to the “anti-vibration function”, the present invention has an anti-vibration effect against a wide range of vibrations and has a greater vibration. An object of the present invention is to provide an image pickup apparatus that can also prevent vibration.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, the imaging apparatus is configured as described in (1 ) below.
[0011]
(1) Image pickup means having a lens barrel and an image pickup device, detection means fixed to the image pickup means for detecting the shake of the image pickup means, and correction for correcting the shake detected by the detection means An image pickup apparatus having a means and a finder, wherein the image pickup means and the detection means fixed to each other are supported by a vibration absorbing material with respect to an exterior member of the image pickup apparatus body, and the viewfinder is supported against the outer member without being supported by the absorbing member, the vibration absorbing material, said correcting means to swing a frequency higher than the correctable shaking frequency, Ru der that there is a vibration damping effect An imaging apparatus characterized by that.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to examples of video cameras. In addition, although an Example is an apparatus which image | photographs a moving image, it can implement similarly in what is called a digital camera which image | photographs a still image, Furthermore, a silver salt film camera etc.
[0021]
【Example】
Example 1
FIG. 1 is a cross-sectional view illustrating a configuration of a “video camera” according to the first embodiment. FIG. 1A is a view of the video camera body as viewed from the front, and shows a state in which the front cover member is removed (a cross-sectional view taken along a plane BB ′ in FIG. 1B). Moreover, FIG.1 (b) represents sectional drawing which cut | disconnected (a) figure by plane AA hit. (B) In the figure, light from a subject passes through a lens barrel 101 and is imaged on an image sensor 102 such as a CCD, and is sent to a substrate 104 having a signal processing circuit via a signal line 103. It is processed as a video signal and recorded by the magnetic recording device 105 or displayed on the finder 106 as necessary. Reference numeral 107 denotes a microphone, and 108 denotes a sensor holding member to which angular velocity sensors 111 and 112 such as a vibration type gyro are fixed, and a detection signal is sent to the substrate 104 via signal lines 109 and 110, respectively. The angular velocity sensors 111 and 112 are fixed to the lens barrel 101 by a sensor holding member 108 and integrated.
[0022]
Reference numeral 113 denotes an exterior (also referred to as a housing) member of the video camera body. As a feature of the present embodiment, the lens barrel 101, the image sensor 102, and the holding member 108 of the angular velocity sensor are integrated and connected to the exterior member 113 via a rubber seat 114 as a vibration absorbing material. The shake detection unit has a structure that is not easily affected by flooding such as camera shake.
[0023]
In this embodiment, the magnetic recording device 105 and the substrate 104 are directly fixed to the exterior member 113, but vibration is absorbed by the flexible portions of the signal lines 103 and 110, and the imaging unit and the shake detection units 101 and 102. , 108 is not affected. In the structure of this embodiment, it is only necessary that at least the integrated imaging units 101 and 102 and the shake detection unit 108 are connected to the main body exterior member 113 via the vibration absorbing material 114, such as the substrate 104 and the magnetic recording device 105. Alternatively, a structure in which the entire video camera main body is integrated with the imaging unit and connected to the exterior member 113 with a rubber seat may be used.
[0024]
A method of connecting the lens barrel 101 and the exterior member 113 via the rubber seat 114 will be described with reference to FIG. The rubber seat 114 is fixed to the lens barrel 101 and the sensor holding member 108 (the pitch angular velocity sensor 111 and the yaw angular velocity sensor 112 are fixed to the sensor holding member 108). (This may be fixed with an adhesive for the sake of simplicity). The rubber seat 114 has a stop hole 114a having a diameter larger than that of the screw 115 screwed from the exterior. At the contact surface between the rubber hole 114a and the screw 115, the lens barrel 101 is held with respect to the exterior member 111 to form a suspended structure.
[0025]
Due to this suspension structure, the vibration transmitted to the imaging system (101, 102) and the vibration detection system (111, 112) has a small amplitude due to the damping action of the rubber seat 114, and a vibration with a high frequency is also eliminated. The Therefore, since the vibration component having a large amplitude and high frequency, which is not good for the camera shake correction means, can be removed by the rubber, the shake component that cannot be removed by the rubber can be easily corrected by the camera shake correction means.
[0026]
Next, electronic vibration isolation will be described with reference to FIG. Reference numeral 101 denotes a lens barrel, and 102 denotes an image sensor such as a CCD. An image on the image sensor 102 is photoelectrically converted, amplified to an optimum level by an amplifier 201 via a flexible wired signal line 103, input to the camera signal processing circuit 202, and converted into a standard television signal.
[0027]
The camera shown in FIG. 2 has an electronic camera shake correction function, and the image stabilization is turned on / off by detecting the state of the switch 211. The angular velocity sensors 111 and 112 detect the shaking angular velocity of the imaging unit composed of the lens barrel 101 and the imaging element 102, amplify them by the amplifiers 207 and 208, respectively, integrate the angular velocity signals by the integrators 209 and 210, and convert them into angular displacements. Then, the image is taken into the image stabilization control unit microcomputer 205. In accordance with the obtained angular displacement, that is, the swing angle θ and the focal length f of the optical system, the microcomputer 205 determines the pixel movement due to the shake on the image sensor 102 (approximately equivalent to f · tan θ) as the movement direction due to the shake. Shake correction is performed by moving in the opposite direction. It should be noted that the angular velocity sensors 111 and 112 are connected to the amplifiers 207 and 208 (in the substrate 104) via a signal line 110 that is flexibly wired.
[0028]
FIG. 3 is a diagram for explaining an image region extracted by electronic image stabilization control. 301 of (a) is an effective pixel area of the image sensor 102, and only a part of the area 302 is extracted, and 302 is set as a starting point (x0, y0) within the range of 301 so as to correct shaking. The image is shaken by moving it, and only the area 302 is displayed on a monitor 106 such as a TV or a viewfinder, or recorded in the magnetic recording device 105 (FIG. 3B).
[0029]
As a technique for this purpose, the image of the area 301 is temporarily stored using a field memory, and the horizontal and vertical scanning lines are interpolated while being enlarged to a size of 303 while reading only the image of the area 302. There are a method of obtaining the display of 303 and a method of using a high-density, high-pixel type large CCD as the imaging device so that the extraction region 302 satisfies the number of scanning lines necessary for the standard TV signal in advance. Since both the former and the latter require an expensive field memory and a large CCD, in this embodiment, a general-purpose PAL CCD is used for an NTSC camera. Since the CCD for PAL has a high pixel density in the vertical direction, the vertical scanning direction is a CCD drive circuit such as a timing generator, and the number of lines to be swept out is angularly displaced within the range of extra lines with respect to the NTSC standard. If it is changed accordingly, the position of the cut-out image in the vertical direction can be changed. Further, in the horizontal scanning direction, if the relationship between the write start pixel position and the read start pixel position to the line memory is changed while performing the enlargement process by the vertical and horizontal ratio by the configuration of the line memory and the memory control circuit, the horizontal scan direction The screen position can be changed, and an inexpensive shake correction device can be realized.
[0030]
FIG. 2 shows the configuration of such a correction system. In the pixel movement in the vertical scanning direction, the microcomputer 205 controls the CCD drive circuit 206 to perform high-speed sweep control, thereby extracting a desired scanning region. The pixel movement in the horizontal scanning direction is performed by taking in the video signal processed by the camera signal processing circuit 202, and by using the line memory 203 and the memory control circuit 204, the readout position of the stored horizontal scanning image is shaken and corrected pixel movement amount In accordance with the ratio, the enlargement process (the memory read rate is changed) corresponding to the vertical / horizontal ratio is performed, the signal is returned to the camera signal processing circuit 202, and the color process is performed to convert it into a standard TV signal.
[0031]
By arranging the video camera having the image stabilization system shown in FIG. 2 in the configuration shown in FIG. 1, two main advantages can be obtained.
[0032]
For one thing, high-frequency vibration components can be removed by the passive vibration-proofing effect of the vibration-proofing members such as rubber seats, and low-frequency by the active vibration-proofing system consisting of the vibration detection system and electronic correction system. Vibration components can be removed, and the effects of camera shake and vibration can be removed over a wide frequency band. This is shown in FIG. FIG. 4 shows the effect of suppressing the vibration frequency. 401 shows the characteristics of the electronic vibration isolation system, and 402 shows the characteristics of the vibration absorbing member.
[0033]
As a second advantage, since the vibration absorbing member can attenuate the vibration and vibration amplitude, the swing angle (converted to the camera rotation angle on the optical axis) that can be corrected by the electronic vibration isolation system:
Maximum correction angle θ = Tan ^-1 (Maximum moving amount of cutout position on CCD / focal length)
Even when the above shaking is applied to the camera body, it is possible to prevent vibration.
[0034]
Although the present embodiment has been described with respect to the configuration using the PAL CCD and the line memory, the correction may be performed by controlling the position of the extracted image using the field memory, or the enlargement control may not be required. A large or ultra-high pixel type CCD may be used. Further, not only an electronic correction system but also an optical camera shake correction system may be used. In this case, the optical correction system may be connected to the camera exterior via a vibration absorbing member. In this embodiment, an angular velocity sensor is used as the shake detection means, but an acceleration sensor may be used. In this case, integration processing may be performed once more in the vibration control microcomputer or outside. Further, although the calculation of the swing angle displacement amount has been described with reference to FIG. 2 as a hardware configuration, it may be processed by software. Further, the rubber material has been described as an example of the vibration absorbing member. However, the present invention is not limited to this, and any material can be used as long as it can absorb vibration and has a high elastic modulus.
[0035]
(Example 2)
In the first embodiment, the case where a shake sensor is used as the shake detection unit has been described as an example. However, in the second embodiment, a case where a so-called motion vector detection unit that detects a shake amount of an imaging system from a change in a captured image is used. It is an example.
[0036]
In this case, only the imaging system including the lens barrel and the imaging element may be used as the suspension structure from the exterior member via the vibration absorbing member. The configuration of FIG. 1 has the same effect as shown in FIG. Can be obtained. The block of the image stabilization system is as shown in FIG. In FIG. 6, the same components as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0037]
The video signal from the camera signal processing circuit 202 is sent to the field memory 301 and the motion detection circuit 303. The motion detection circuit 303 extracts a changed portion of the subject from continuous video signals (for example, between fields) and outputs the extracted portion to the image stabilization control unit 304. In accordance with the motion signal, the image stabilization control unit 304 determines whether the screen is moving partly or the entire screen (whether the camera is moving). In the latter case, the motion is corrected. The correction command to be output is output to the memory control circuit 302. The memory control circuit 302 extracts the area selected according to the correction signal from the video information stored in the field memory 301, returns the signal to the camera signal processing circuit 202, and performs color processing etc. to convert it into a standard TV signal. To do. In the image stabilization system using the field memory 301, it is not necessary to perform image cutout in the vertical direction by high-speed sweeping control by the CCD drive circuit 206.
[0038]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an imaging apparatus that has a vibration suppression effect against a wide range of frequency fluctuations and can prevent vibrations even from larger vibrations. Specifically, at least the imaging system and the shake detection sensor connected to the imaging system (only the imaging system may be used in the case of motion vector detection) are supported from the housing member that is the exterior of the imaging device via the vibration absorbing material. As a result, the vibration transmitted from the image pickup apparatus body to the image pickup system is removed from the high frequency component, and the low frequency shake component transmitted to the image pickup system is suppressed by the shake detection means and the correction means. Therefore, to provide a comfortable imaging device that eliminates camera shakes and vibrations caused by vibrations in every shooting situation, from hand-held shooting to shooting on a tripod on a vehicle or on a ship, and shooting on a bridge girder on a footbridge. Is possible.
[0039]
In particular, through the vibration absorber, it is possible to sharply attenuate the swing amplitude transmitted from the main body to the imaging system, so that even for a large shaking shooting situation, the swing to the imaging system has a small amplitude, Vibration isolation is possible. As a result, it is possible to provide an imaging apparatus capable of realizing comfortable shooting, in which the shake correction range can be expanded and a stable captured image without blurring can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of Example 1. FIG. 2 is a block diagram showing a configuration of a main part of Example 1. FIG. 3 is an explanatory diagram of electronic vibration isolation. FIG. FIG. 5 is a cross-sectional view showing the configuration of the second embodiment. FIG. 6 is a block diagram showing the configuration of the main part of the second embodiment.
101 Lens barrel 102 Image sensor 108 Sensor holding member 114 Rubber seat (vibration absorbing member)

Claims (1)

An image pickup means having a lens barrel and an image pickup device; a detection means fixed to the image pickup means for detecting a shake of the image pickup means; a correction means for correcting the shake detected by the detection means; An imaging apparatus having a finder, wherein the imaging means and the detection means fixed to each other are supported by a vibration absorbing material with respect to an exterior member of the imaging apparatus main body, and the finder is supported by the vibration absorbing member is supported against the outer member without being supported, the vibration absorber, wherein the correction means to swing a frequency higher than the correctable shake frequency, characterized in der Rukoto that there is vibration damping effect An imaging device.

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