JP3543999B2 - Optical equipment having image blur prevention device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an optical device having an image blur prevention device in a camera, a video camera, another optical device, or the like.
[0002]
[Prior art]
In recent years, in the field of camera devices such as video cameras and still cameras, miniaturization and weight reduction have been remarkable, and at the same time, high functionality has been measured. One of such advanced functions is to increase the magnification of a photographing lens, and zoom lenses having a magnification of 10 times or 12 times have become common in the field of home cameras.
[0003]
However, when the focal length on the long focal length side becomes a large numerical value due to such an increase in the zoom ratio, the influence on the recorded image is increasing, and in a moving image such as a video camera, The main subject may move unsightly on the screen, or a shake image may be recorded in a still image. Further, in the case of still images, for example, by increasing the shutter speed, it is possible to avoid the problem to some extent.However, in the case of moving image recording, since the recording is primarily on the time axis, the effect of camera shake is affected by the shutter speed. It cannot be avoided by setting. Under such circumstances, in the field of video cameras, in particular, a shake preventing device for removing the influence of camera shake has been put to practical use.
[0004]
This shake prevention device includes at least shake detection means for detecting a shake component, and shake correction means for correcting shake in accordance with the detection result of the detection means. As the shake detection means, there is a so-called electronic detection method of comparing images between two continuous screens, and a method of directly measuring the actual camera movement using an angular velocity meter, an angular accelerometer, or the like. Can be
[0005]
In addition to the so-called electronic correction method of electronically selecting a range (cutout range) to be actually recorded from obtained images, the shake correction means optically sets the angle of the photographing optical axis. Optical shake correction means for adjusting the direction in which the camera shake is removed is given.
[0006]
Among the optical shake correction means, in particular, a method using a variable apex angle prism,19 to 23This will be described below with reference to FIG.
[0007]
FIG. 19 shows a configuration of the variable apex angle prism. 19 (A), (B) and (C), reference numerals 21 and 23 denote glass plates, and 27 denotes a bellows portion made of a material such as polyethylene. In the interior surrounded by these glass plates 21 and 23 and bellows 27, a transparent material such as silicon oil is used.Liquid 22Is enclosed.
[0008]
In FIG. 19B, the two glass plates 21 and 23 are in a parallel state.Ray 25Are equal in incidence angle and emission angle. On the other hand, when the light beam has an angle as shown in (A) and (C), the light beam is bent at a certain angle as shown by light beams 24 and 26, respectively.
[0009]
Therefore, when the camera is tilted due to camera shake or the like, the camera shake can be removed by controlling the angle of the variable apex prism provided in front of the lens so that the spectral line corresponding to the angle is bent. .
[0010]
FIG. 20 shows this state. Assuming that the variable apex angle prism is in a parallel state in FIG. 20 (A) and the optical axis captures the center of the subject, a degree as shown in FIG. By driving the variable apex angle prism to bend the light beam as shown in the figure against the blur, the photographing optical axis remains unchanged, and the center of the subject can be continuously captured.
[0011]
FIG. 21 is a diagram showing an actual configuration example of a variable apex angle prism unit including the variable apex angle prism, an actuator for driving the prism, and an apex angle sensor for detecting an angle state.
[0012]
Since the actual blur appears in all directions, the front glass surface and the rear glass surface of the variable apex angle prism are configured to be rotatable about a direction shifted by 90 degrees as a rotation axis. Here, the respective components in these two rotational directions are shown as subscripts a and b, but those having the same numbers have exactly the same functions. Parts of the b side are not shown.
[0013]
Reference numeral 41 denotes a main body of the variable apex prism, which is composed of the glass plates 21 and 23, the bellows 27 and the internal liquid. The glass plate is integrally attached to the holding frame 28 using an adhesive or the like. The holding frame 28 forms a rotating shaft 33 with a fixed component (not shown), and is rotatable around this axis. The axis 33a and the axis 33b are different in the direction by 90 degrees. A coil 35 is integrally provided on the holding frame 28, while a fixed portion (not shown) is provided with a magnet 36 and yokes 37 and 38. Therefore, the variable apex angle prism is rotated around the axis 33 by passing a current through the coil. A slit 29 is provided at the tip of an arm portion 30 integrally extending from the holding frame 28, and a vertex angle sensor is provided between a light emitting device 31 such as an iRED device provided on a fixed portion and a light receiving device such as a PSD. Make up.
[0014]
FIG. 22 is a block diagram showing the configuration of an image stabilizing lens system in which a shake preventing device having the variable apex angle prism as a shake correcting unit is combined with a lens.
[0015]
FIG.In the figure, 41 is a variable apex prism, 43 and 44 are apex angle sensors, 53 and 54 are detection circuit parts for amplifying the output of the apex angle sensor, 45 is a microcomputer, and 46 and 47 are shake detecting means composed of angular accelerometers and the like. , 48 and 49 are actuators composed of the coil 35 to the yoke 38 and the like, and 52 is a lens.
[0016]
The microcomputer 45 controls the variable apex prism to an optimal angle state for removing blur according to the angular state detected by the apex angle sensors 43 and 44 and the detection results of the blur detecting means 46 and 47. Next, the current supplied to the actuators 48 and 49 is determined.
[0017]
The reason why the main element is composed of two blocks is that it is assumed that control in two directions shifted by 90 degrees is performed independently.
[0018]
FIG. 23 is a diagram showing a more detailed structure of a conventional variable angle prism. In FIG. 23, 21 and 23 are glass plates, 22 is a liquid sealed therein, 27 is a bellows portion, and 25 is an optical axis. Reference numerals 59 to 62 denote films formed of four donut-shaped parts for forming the bellows portion 27, 57 denotes a joint between the films, and 58 denotes a joint between the film and the frame. Further, it is composed of two parts, a frame 55 and a frame core 56.
[0019]
The joint 57 between the films is joined by welding. For this reason, the material of the films 59 to 62 is preferably a material excellent in heat sealability at least on both surfaces of the surface layer, and for example, polyethylene (PE), polypropylene (PP) and the like are generally used. Further, the frame 55 and the glass plate 21 or 23 are fixed using an adhesive, but the joint 58 between the frame 55 and the films 59 and 62 constituting the bellows is the same as the joint 57 when welding is used. And the same material as the film surface. However, the above-mentioned materials having excellent heat-sealing properties have drawbacks in that the precision of parts is hardly obtained compared to, for example, polycarbonate (PC) which is frequently used around a lens barrel, and the rigidity is low and the material is easily deformed. have. Therefore, reference numeral 56 denotes a frame core material provided to avoid this problem. The frame core 56 is made of a plastic or a metal such as aluminum or stainless steel, which has higher rigidity than the material of the frame 55 and has a high heat deformation temperature. The frame 55 is formed around the frame core 56. Thereby, the flatness of the portion of the frame 55 where the film is welded, the strength or dimensional accuracy of the body-attached portions of the glass plates 21 and 23, or the dimensional accuracy of the fitting diameter of glass are obtained.
[0020]
The configuration in the case where the variable vertex angle prism is used as the optical shake correction means has been described above.
[0021]
Next, as another example of the optical shake correction means, a method of movably disposing a correction optical system as disclosed in, for example, US Pat. No. 2,959,088 will be described.
[0022]
FIG. 24 shows the overall configuration.
[0023]
In FIG. 24, lenses 71 and 72 are correction optical systems with respect to main lenses 82 and 83. The focal length of the correction optical system is set as follows. The focal length of the lens 71 having a negative power fixed to the lens barrel 74 is represented by f₁ And the focal length of the lens 72 having a positive power supported by the movable support 73 is represented by f_Two Then
f₁ = -F_Two
The focal length of each lens is set so as to satisfy the following relationship.
[0024]
Gimbal for supporting biaxial movement75Supports the lens 72.
[0025]
A counterweight 80 is provided to balance the correction optical system.
[0026]
By satisfying such optical conditions, a shake preventing device including a so-called inertial pendulum type optical shake correcting means can be realized.
[0027]
Next, a description will be given of the biaxial movement of the gimbal 75 with reference to FIG.
[0028]
The lens 72 is supported by a support member 75y having a degree of freedom in the y-axis direction, and the support member 75y is supported by a support member 75x having a degree of freedom in the x-axis direction perpendicular to the y-axis direction. Is supported by the lens barrel 74.
[0029]
With such a configuration, a correction optical system having two degrees of freedom can be configured.
[0030]
Next, a representative example of a zoom lens when the shake correcting means having the variable apex angle prism described above is combined with a zoom lens will be described. Here, a so-called inner focus or rear focus zoom lens in which focusing is performed by a lens group behind the variator lens group for zooming will be described.
[0031]
Various such lens types are known. FIG. 26 shows an example in which the rearmost lens group is used for focusing. In the figure, 111 is a fixed front lens group, 112 is a variator lens group, 113 is a fixed lens group, and 114 is a focusing (compensator) lens group. 133 is a guide rod for preventing rotation, 134 is a variator feed rod, 135 is a fixed lens barrel, 136 is an aperture unit (inserted at a right angle to the plane of the drawing) 137 is a step motor where a focus motor is provided, and 138 is a focus motor. Male screw processing for moving the lens with the output shaft of the step motor is performed. 139 is a female thread portion that meshes with the male screw, and is integrated with the moving frame 140 of the lens 4. 141 and 142 are guide bars of the lens 4 moving frame, 143 is a rear plate for positioning and holding the guide bar, and 144 is a relay holder. 145 is a zoom motor, 146 is a zoom motor speed reducer unit 147, 148 is an interlocking gear, and 148 is fixed to the zoom feed rod 134.
[0032]
When the step motor 137 is driven by the above configuration, the focus lens 4 moves in the optical axis direction by screw feed. When the zoom motor 145 is driven, the gears 147 and 148 are interlocked and the shaft 134 is rotated, so that the variator 2 moves in the optical axis direction.
[0033]
FIG. 27 shows the positional relationship between the variator lens and the focusing lens in such a lens according to some distances. Here, as an example, the in-focus positional relationship with respect to each subject of infinity, 2 m, 1 m 80 cm, and 0 cm is shown. In the case of inner focus, since the positional relationship between the variator and the focus lens varies depending on the subject distance, the lens groups cannot be linked with a simple mechanical structure like a cam ring of the front lens focus lens. .
[0034]
Therefore, simply driving the zoom motor 145 under the structure as shown in FIG. 26 will cause blurring.
[0035]
Due to the above characteristics, the inner focus lens has advantages such as "small number of lenses" in addition to the above-mentioned advantage of "excellent shooting ability" compared to the front lens focus lens. Nevertheless, practical application was delayed.
[0036]
However, in recent years, a technique for optimally controlling the lens positional relationship as shown in FIG. 27 according to the subject distance has been developed, and commercialization has been carried out.
[0038]
In Japanese Unexamined Patent Publication No. 1-280709 by the present applicant, the positional relationship between the variator and the compensator (focus lens) is maintained by the method shown in FIGS.
[0039]
FIG. 28 shows a block diagram. Reference numerals 111 to 114 denote the same lens groups as those shown in FIG. Variator lens group112Is detected by the zoom encoder 149Is done. hereAs a type of the encoder, for example, a volume encoder configured to slide a brush integrally attached to a variator moving ring on a substrate on which a resistance pattern is printed can be considered. Reference numeral 150 denotes an aperture encoder for detecting an aperture value, for example, using a Hall element output provided in an aperture meter. Reference numeral 151 denotes an image sensor such as a CCD, and 152, a camera processing circuit. The Y signal is taken into an AF circuit 153. The AF circuit determines whether the subject is in focus or out of focus. If the subject is out of focus, it is determined whether the focus is on the front focus or the back focus, and the degree of defocus is determined. These results are taken into the CPU 154.
[0040]
A power-on reset circuit 155 performs various reset operations when the power is turned on. Reference numeral 156 denotes a zoom operation circuit which, when the operator operates the zoom switch 157, notifies the CPU 154 of the operation. 158-160FIG.Is the direction data 158, speed data 159, and boundary data 160. Reference numeral 161 denotes a zoom motor driver, 162 denotes a step motor driver, and the number of input pulses of the step motor is continuously counted in the CPU and used as an encoder for the absolute position of the focus lens. In such a configuration, since the variator position and the focus lens position are obtained by the zoom encoder 149 and the number of step motor input pulses, one point on the map shown in FIG. 27 is determined. On the other hand, the map shown in FIG. 27 is divided into small zigzag areas by the boundary data 160 as shown in FIG. Here, the shaded area is an area where the placement of the lens is prohibited. When a point on the map is determined in this way, it is possible to determine an area of the small area to which the point belongs.
[0041]
In the speed data and direction data, the rotation speed and direction of the step motor obtained from the locus passing through the center of each area are stored in each area. For example, in the example of FIG. 29, the horizontal axis is divided into ten zones. Now, assuming that the zoom time is 10 seconds, the passage time of one zone is naturally 1 second. 30 is an enlarged view of the block III in FIG. 29, a locus 164 passes through the center of the block, a locus 165 passes through the lower left, and a 166 passes through the upper right. Here, if the center locus moves at a speed of xmm / sec, the locus can be traced with almost no error.
[0042]
When the speed thus obtained is referred to as a region representative speed, the speed memory stores values corresponding to the respective regions in the number of small regions. When this speed is shown as 168, the representative speed is finely adjusted to 167 or 169 according to the detection result of the automatic focus adjustment device, and the step motor speed is set. In the direction data, since the rotation direction of the step motor changes according to the area even in the same tele-to-wide (wide to tele) zoom, this code is stored in the memory.
[0043]
In addition to the area representative speed obtained from the variator and the focus lens position as described above, the stepping motor speed is corrected by using the stepping motor speed determined by correcting this speed based on the detection result of the automatic focus detection circuit. Is driven to control the position of the focus lens, it is possible to prevent out-of-focus even during zooming even with an inner focus lens.
[0044]
Here, in addition to the representative speed of 168 in FIG. 30, speeds such as 167 and 169 are stored for each block, and one speed is selected from three types of speeds according to the detection result of the automatic focus detection device. A method for performing this is also disclosed in Japanese Patent Application Laid-Open No. 2-173605 by the present applicant.
[0045]
In addition to the method of storing such speeds, some curves such as ∞, 2m and 1m shown in FIG. 27 are stored as memories of focus lens positions corresponding to a plurality of variator positions. In the case of an intermediate distance between the stored curves, there is also known a method in which the positional relationship between the two lens groups to be obtained from the data of the upper and lower stored curves is calculated by interior calculation.
[0046]
FIG. 31 shows an example of a configuration in a case where the shake correcting means using the zoom lens and the variable apex angle prism is connected to the above-described zoom lens.
[0047]
In FIG. 31, reference numeral 263 denotes a rotating shaft portion provided integrally with the holding frame 28, and 267 denotes a rotating shaft opposite to the rotating shaft 263. And the like are thickened in the holding frame. 268 is a leaf spring, 269 is a screw for fixing the leaf spring, and 266 is a flat glass, which is provided to prevent a photographer or the like from directly touching the variable apex prism and damaging it. Reference numeral 265 denotes a mounting screw for accessories, and 264 denotes a fixed lens barrel part including a hole for a rotary bearing of the variable apex prism.
[0048]
The lens barrel part 264 is fastened to the fixed lens barrel 135 of the zoom lens by a screw 270.
[0049]
In FIG. 31, components such as a holding frame for rotating the glass in front of the variable apex angle prism, an actuator, and a sensor unit for detecting the apex angle are not shown for simplicity.
[0050]
[Problems to be solved by the invention]
However, when the above-described optical shake correction means such as using a variable apex angle prism or making the correction optical system movable is used, particularly when the correction angle is large, or the focal length of the combined zoom lens is large. Alternatively, in a situation where a part of a screen is enlarged and recorded by electronic zooming or the like, there is a concern that color shift due to the influence of chromatic aberration that occurs in principle by bending the optical axis becomes noticeable.
[0051]
Conventionally, this problem has been suppressed to a level below the level at which it is almost a problem. However, in the future, the image quality will be improved by increasing the number of pixels of the CCD which is an image sensor. Considering the background such as the tendency of so-called electronic zoom) to be generalized, the emergence of cameras with improved image quality such as 3CCD cameras, etc. It may contribute as a factor of image quality degradation.
[0056]
[Means for Solving the Problems]
The present inventionIs a photographing lens having an optical axis, an image pickup means for picking up an image from the photographing lens, a shake detecting means for detecting a shake, and an image shake preventing means for correcting the image shake by tilting the optical axis by being movable. Means for detecting a resolution in a processing format of an image picked up by the image pickup means, and control means for controlling driving of the image blur prevention means in accordance with an output from the shake detection means, wherein the control means When the means for detecting the resolution detects the first resolution, the movable range of the image blur prevention means is set to the first movable range, and the means for detecting the resolution is higher than the first resolution. When a high second resolution is detected, the movable range of the image blur prevention unit is set to a second movable range smaller than the first movable range.It is characterized by:
[0057]
In addition, the present inventionComprises: a zoom lens having an optical axis; imaging means for capturing an image from the zoom lens; focal length detection means for detecting a focal length of the zoom lens; blur detection means for detecting blur; Means for correcting the image blur by tilting the optical axis, means for detecting the resolution in the processing format of the image captured by the image sensor, and preventing the image blur according to the output from the blur detection means Control means for controlling the driving of the means, wherein the control means sets the movable range of the image blur prevention means to the first movable range when the means for detecting the resolution detects the first resolution. Then, when the detection result of the resolution detecting means detects a second resolution higher than the first resolution, the movable range of the image blur prevention means is detected by the focal length detecting means. Set to a second movable range smaller than the first movable range in response to the focal length becomes longerIt is characterized by:
[0060]
【Example】
(First embodiment)
FIG. 1 is a block diagram of the first embodiment of the present invention.Show. In FIG. 1, the same components as those in FIG. 22 are denoted by the same reference numerals, and description thereof will be omitted.In FIG. 1, reference numeral 1 denotes a focal length sensor which detects a position of a variator lens of a zoom lens and the like. Various detection methods are conceivable, for example, a method of detecting by sliding a brush on a fixed variable resistance pattern integrally provided with a lens barrel for fixing the lens, and a method of detecting the movement of the lens group. A method is provided in which a step motor is provided and position detection is performed by continuously counting the number of drive pulses input to the step motor from a reference position.
[0061]
Reference numeral 2 denotes maximum shake angle data which is stored in a microcomputer, for example, as a table corresponding to the focal length.
[0062]
That is, conventionally, no information on the photographing lens is used in the shake preventing apparatus including the variable apex angle prism as shown in FIG. 22, but in the first embodiment, the information on the focal length is used. The variable apex angle is controlled by a microcomputer for controlling a variable apex angle in order to prevent a shake.
[0063]
Even when using other optical shake correction means such as a method in which the above-described correction optical system is movable using a gimbal, the present invention can be similarly implemented by regulating the movable range of the movable part. Become.
[0064]
With reference to FIG. 2, the chromatic aberration of magnification caused by using a prism will be described. When white light is incident on a prism having a certain angle as shown in the figure, the emitted light causes an angular shift according to the wavelength. Therefore, if such a prism is arranged in front of the image forming optical system, an image is blurred because the image forming position changes according to the wavelength. In particular, color misalignment tends to be conspicuous at black and white edges having high contrast.
[0065]
In general, the design (achromatism) of suppressing the influence of the chromatic aberration is performed in the design of a zoom lens or the like. However, when a variable apex angle prism is used, the amount of color shift varies depending on the apex angle state. That is, in a standard state (a state in which two glasses are parallel), the color shift caused by the variable apex angle prism is zero, but the amount of the color shift increases as the apex angle increases.
[0066]
FIG. 3 shows the relationship between the focal length and the color shift, and the relationship between the focal length and the optical axis correction angle when the variable apex angle prism is in the use maximum angle state.
[0067]
The term “color shift” as used herein means an image position shift between light beams of two wavelengths on an image plane.
[0068]
In the figure, it is assumed that the relationship between the focal length and the color shift is written on a log-log graph. It is assumed that the optical axis correction angle is 1 ° at any focal length. This is expressed as ε = (n−1) × θ, where θ is the angle of the variable apex angle prism, ε is the optical axis correction angle, and n is the refractive index of the liquid inside the variable apex angle prism. This is because if the constant maximum apex angle is set regardless of the value, the same value is obtained. On the other hand, the influence of the chromatic aberration becomes more conspicuous as the focal length increases (the graph of the focal length and the color shift is indicated by a chain line).
[0069]
In contrast, FIGS. 4A and 4B show the case of the first embodiment of the present invention. FIG. 4A shows an example in which the focal length at which a predetermined color shift amount is reached is set as a boundary, and on the long focal length side, the maximum shake angle is set to be small so that the color shift has a predetermined value.
[0070]
FIG. 4B shows a case in which the set value of the maximum use apex angle is smoothly varied according to the focal length so that a predetermined color shift occurs at the longest focal length.
[0071]
It is preferable to reduce the maximum use shake angle on the long focal length side for the following reasons. That is, according to the studies by the inventors, the amount of camera shake that occurs when a still object is photographed in a normal hand-held state is from ± 0.3 ° at the optical axis angle to about 0.5 ° at most. Dominant. On the other hand, when the camera is shaken by panning, etc., in order to drive and control the variable apex prism without discomfort, the use of the optical axis correction angle that is much larger than the optical axis correction angle required to eliminate the influence of camera shake of the stationary subject If you do not secure enough movable area to perform panning control by providing an angle range, the inclination of the variable apex angle prism will reach the end of the used angle range during panning and the screen will bump into the screen Will occur. On the other hand, if the used angle range is set large, low-frequency, large-amplitude vibration may remain during normal camera shake correction. This is often due to the characteristics of the shake detection sensor, filter characteristics provided for the output of the shake detection sensor, and the like.
[0072]
On the other hand, considering actual photographing, panning and the like are frequently used at a wide focal length to a middle focal length, and at a telephoto end (the longest focal length) (of course, depending on the numerical value, for example, a 400 mm in a 35 mm format of a film camera). It is rare that panning is heavily used.
[0073]
As described above, in general, if the maximum apex angle range at the telephoto end is restricted as in the present invention and the correction is not made insufficient (for example, 1 °), the still object can be shot still. In this case, it is possible to sufficiently prevent camera shake, and even if a slight squeaky feeling occurs during panning, it can also contribute to reducing the remaining of the low-frequency large-amplitude screen shake. It becomes more preferable.
[0074]
When a large angle is required for shake correction in a special case (such as photographing from a car or a boat), it is possible to cope with a manual setting of a shake angle by a photographer in an embodiment to be described later.
[0075]
FIG. 5 shows a flowchart of setting the target apex angle value of the microcomputer 45 of the first embodiment.
[0076]
Start with step 1. In step 2, the focal length information at that time is read from the detection result of the focal length sensor 1. Next, in step 3, the maximum deflection angle value corresponding to the focal length at that time is read from the table of the maximum deflection angle (vertical angle) data 2. In step 4, the value θ_M Set. In step 5, the detection result from the shake detection sensor is used to correct the vertex angle θ._P Read as In step 6, both values are compared. As a result, θ_P Is smaller in step 7 as the target apex angle position θ._PIs set. As a result of step 6, θ_P Is larger in step 8 as the target apex angle position θ_M Is set.
[0077]
(Second embodiment)
In the first embodiment, the content in which the used maximum apex angle (shake angle) is changed based on the focal length information has been described. In the second embodiment of the present invention, not only the maximum apex angle used, but also a threshold value on the angle used for control, or a coefficient between the output of the blur detection means and the apex angle displacement amount. Also, by changing the setting, a more sophisticated blur prevention device is provided.
[0078]
FIG. 6 is a block diagram showing a main part configuration of the second embodiment. This configuration is different from the first embodiment in that K, θ_T It has data 3 and is a coefficient between the maximum shake angle, the output of the combined shake detecting means, and the amount of displacement of the apex angle, according to the detection result of the focal length. K value, θ_T Is made variable, thereby achieving a blur prevention device that does not cause a sense of discomfort. Note that the description of the same configuration as in FIG. 1 is omitted here.
[0079]
The K value will be described with reference to FIG. In FIG. 7, the horizontal axis indicates the angle change of the photographing optical axis by driving the variable apex prism or the correction optical system (0 ° is a standard position). As described above, in a case where a still subject is photographed in a still state, if there is a correction angle range of about ± 1 °, blur correction can be performed. On the other hand, when a large shake angle is detected by the shake detection means due to panning or the like, if the shake is completely corrected and the camera is shaken at the start of panning, the subject stops and the image is taken. When panning is stopped, recording is performed as if panning is continued even if the camera is stopped.
[0080]
Therefore, in many cases, for such a large amplitude, the target position in the microcomputer 45 is not set as the detection result of the shake detecting means, but is reset to a smaller target position. There are various methods for this. For example, the detection result of the shake detecting_P And the target position is θ, and the threshold angle is θ_T1, Coefficient K,
θ_P ≤θ_T1At the time, θ = θ_P
θ_T1<Θ_P <Θ_M At the time, θ = θ_T1+ (Θ_P −θ_T1) × K
By performing such calculations, the target apex angle (shake angle) is set (provided that each value is positive).
[0081]
FIG. 7 shows θ and θ in this case._P And the threshold angle θ_T1In a range where the absolute value is larger, the target apex angle (shake angle) is set smaller. FIG. 8 shows actual setting values. Focal length is f_W To f_T A zoom lens with a focal length of_M1And f_M2(I preferably divide equally on a logarithmic graph). When the focal length is in each area, each value is set as shown in FIG. As a result, θ and θ_P Is as shown in FIG. In the figure, the solid line indicates the case of the region I, the broken line indicates the case of the region II, and the dashed line indicates the case of the region III.
[0082]
FIG. 10 is a flowchart showing the operation of the microcomputer for controlling the drive of the variable apex angle prism with the characteristics shown in FIGS. In step 1, the process starts, and in step 9, the focal length state is detected. In step 10, the threshold value θ is obtained from the information provided in the microcomputer as shown in FIG._T1, K, θ_M Is determined respectively. In step 12, the detection result from the shake detecting means is defined as a value θ as a dimension of the apex angle or the shake angle._P Is read. In step 13, this θ_P Absolute value of θ_T1Are compared, and as a result, the absolute value θ_P Is smaller than the target value θ in step 14,_P Is set. Also, the absolute value θ_P Is θ_T1If it is larger than the above, in step 15 θ_M Is compared. Absolute value θ_P Is θ_M If it is larger, a positive / negative determination is made in step 16;_M , If negative, −θ in step 17_M Set. In step 15, the absolute value θ_P Is θ_M In the following cases, a positive / negative determination is made in step 19, and if positive, a step 20 is performed, and if negative, a step 21 is performed to calculate the target position according to the above-described formula.
[0083]
In this example, the focal length is divided into three regions. However, more divisions or two divisions may be used. Further, a plurality of threshold angles may be provided instead of one, and the K value may be finely set in accordance with each. Further, instead of determining the coefficients and thresholds using a table as in this example, the target angle θ and the blur detection angle θ_P It is also conceivable to provide an arithmetic expression between the above and calculate the target vertex angle (shake angle) by calculation.
[0084]
Also, θ and θ_P It goes without saying that not only the first-order relationship shown in FIG.
[0085]
(Third embodiment)
In the first and second embodiments, the amount of color misregistration can be reduced by making the maximum apex angle or the threshold between the control and the coefficient between the output of the blur detection means and the apex angle displacement variable according to the focal length. At the same time, the anti-shake performance desired in practical use was achieved.
[0086]
In the third embodiment of the present invention, not only the focal length information but also whether or not the subject is conspicuous in color misregistration is determined from the value of the focus voltage of the automatic focusing device using the high frequency component of the video signal, and based on this information. Alternatively, from both of this information and the above-mentioned focal length information, setting of the maximum apex angle (vibration angle) as described in the first and second embodiments, the threshold value for control, and the above-mentioned coefficient is performed. To present.
[0087]
FIG. 11 is a block diagram showing a main part configuration of the third embodiment. The description of the same configuration as in FIG. 1 is omitted here. The information formed on the CCD 151 is processed by the camera processing circuit 152 into a predetermined TV signal, for example, an NTSC signal in Japan. Among them, the Y signal corresponding to the luminance is taken into the AF circuit 153, where the high-frequency component of the Y signal is obtained as the focus voltage. FIGS. 12A to 12C illustrate this focus voltage.
[0088]
In FIG. 12A, the subject has a black portion 272 and other white portions, and the Y signal of the signal capturing area 271 for automatic focus detection is as shown at 273 in FIG. 274 of FIG. 12C is a signal obtained by differentiating the signal 273, and the peak height V of the signal 273 is obtained._F Is the focal voltage.
[0089]
Generally, the color shift is conspicuous at the black-and-white edge portion, that is, a subject having a high contrast. Therefore, the microcomputer 45 sets a certain threshold value for the focus voltage, and when a focus voltage exceeding the threshold value is obtained, it is determined that the subject has a high contrast. For example, the focal length of the region I in FIG. However, it is possible to suppress the occurrence of color misregistration by adopting a method such as changing the setting to each value of III.
[0090]
FIG. 13 shows an example of this selection table, in which combinations of the values I to III shown in FIG. 8 are selected from both the focal length and the contrast state determined from the focal voltage.
[0091]
Various methods other than the above-described method using the focus voltage of the automatic focusing device can be used for detecting the contrast. For example, in general, a bright subject often has a higher contrast than a dark subject. From this point, it is conceivable that the contrast is roughly determined using the aperture information.
[0092]
FIG. 14 is a block diagram showing a configuration for performing this control, and a description of the same configuration as in FIG. 1 will be omitted here. In this configuration, the detection result of the aperture encoder 150 is taken into the microcomputer 45, and the maximum vertex angle (shake angle) is set based on this information.
[0093]
It should be noted that the focal length information and the focal voltage information may be used as a material for the determination together with FIG. Also, in FIGS. 11 and 14, only block 1 of the maximum deflection angle data is described, but K, θ described in the second embodiment are used._T Data block 3 may be added.
[0094]
(Fourth embodiment)
The present invention controls the optical blur correction means so that the image quality does not deteriorate due to color misregistration.The format of the record, which is the resolution in etc.It depends. As is well known, home video formats include 8 mm and its high band version Hi8, VHS and its high band version S-VHS. The effect of color shiftNormal version resolutionBut,High band version resolutionConfusing. From this, in the fourth embodiment,Recording format that is the resolutionIt is proposed to switch between a case where the control is changed as shown in the first to third embodiments and a case where the control is not changed according to the first embodiment.
[0095]
FIG. 15 is a block diagram showing a main part configuration of the fourth embodiment. The description of the same configuration as in FIGS. 6, 11, and 14 is omitted here. In the configuration of FIG. 15, the recording format is detected at block 276, and this information is sent to the microcomputer 45.
[0096]
FIG. 16 is a flowchart for determining the target value. It starts in step 22. In the step 23, it is determined whether the recording format is 8 mm or Hi8 in the case of this example. If the recording format is 8 mm, the control is not changed as shown in the first to third embodiments, and θ = θ in the step 24._P And In the case of Hi8, for example, the processing is connected to the flowchart shown in FIG.
[0097]
FIG. 16 is an example, and in the case of the standard (8 mm, VHS), for example, a combination of the values of II shown in FIG. 8 may be fixed. Furthermore, the detection result of the recording format can be used in the same row as the focal length, the focal voltage, and the aperture value.
[0098]
(Fifth embodiment)
In the fifth embodiment, the signal processing of the camera is digitized, and a case where the present invention is applied to a video camera or the like having an electronic enlargement function (so-called electronic zoom function) accompanying the digitalization is shown in FIGS. A fifth embodiment will be described.
[0099]
In FIG. 17, the portions having the same numbers as those in FIGS. 15 and 28 indicate the same functions. Reference numeral 278 denotes a digital signal processing circuit of a camera including A / D conversion, which incorporates an AF circuit therein. Reference numeral 279 denotes an IC for digital effects, which performs enlargement for electronic zoom and other processes for obtaining various effects. Reference numeral 280 denotes a digital effect operation unit operated by the photographer, and 281 denotes a D / A conversion.
[0100]
In this case, in the above-described embodiment, the maximum apex angle (deflection angle), K, θ_T Information for selection, such as, is sent from the lens control CPU 154 to the microcomputer 45 for the blur prevention device. When the photographer operates the external operation key 157 for zooming, if the operation in the telephoto direction continues even though the camera is already at the optical telephoto end, a command is sent to the digital effect IC to enter the electronic zoom range. The information is also transmitted from the CPU 154 to the microcomputer 45. The microcomputer 45 calculates the maximum apex angle or K, θ from these information._T Set the value of.
[0101]
FIGS. 18A and 18B show the setting of the maximum apex angle when the electronic zoom region is continuously provided at the tele end of the optical zoom. In FIG. 4A, the setting of the maximum apex angle is made variable while entering the electronic zoom range, and the effect of color misregistration is reduced to a predetermined value or less.
[0102]
FIG. 18B shows a configuration in which the setting of the maximum apex angle (shake angle) is smoothly changed from the optical zoom range to the electronic zoom range.
[0103]
(Sixth embodiment)
By making the values for various controls of the camera shake prevention device variable according to various types of information such as the focal length as described above, it is possible to eliminate the influence of color shift and perform control in accordance with the focal length. In some cases, for example, even if color misregistration occurs to some extent, it may be desirable to perform even large amplitude hand shake prevention.
[0104]
For example, photographing from a ship corresponds to this.
[0105]
In such a case, it is possible to configure so that the change of the control performed in the fifth embodiment is turned off by the mode switching 277 by the photographer in FIG.
[0106]
In the present invention, each component or a part of the components of the claims or the embodiments may be provided in a separate device. For example, the shake detecting device may be provided in the camera body, the shake correcting device may be provided in the lens barrel mounted on the camera, and the control device for controlling them may be provided in the intermediate adapter.
[0107]
The present invention is not limited to the means for directly preventing the shake as the shake preventing means, and the user may be warned by light, sound, or the like that the shake is occurring or may be caused by the user. May be indirectly prevented from generating a shake.
[0108]
The present invention provides any method capable of detecting a shake, such as an angular accelerometer, an accelerometer, an angular velocimeter, a speedometer, an angular displacement meter, a displacement meter, and a method of detecting image shake itself. It may be something like this.
[0109]
The present invention, as a shake preventing means, a light flux changing means such as a shift optical system or a variable-length prism that moves an optical member in a plane perpendicular to the optical axis, and an apparatus that moves an imaging surface in a plane perpendicular to the optical axis, Furthermore, any device that can prevent shake, such as one that corrects shake by image processing, may be used.
[0110]
The present invention is also applied to a case where an image blur prevention means such as a variable apex angle prism is provided in an interchangeable lens that can be attached to both a silver halide camera and a video camera, and the interchangeable lens is attached to a video camera. In such a case, the operating range of the image blur prevention means may be made larger than when the camera is mounted on a silver halide camera.
[0111]
That is, since the image plane (CCD) of a video camera is generally smaller than the image plane of a silver halide camera, the area in which aberration must be taken into consideration naturally becomes smaller, and the image blur prevention means can be displaced more largely. In the above-described example, this is utilized to make the operation range different, and to prevent image blurring in a wide range if possible.
[0112]
In the above-described embodiment, the microcomputer 45 corresponds to the control means of the present invention.
[0113]
The above is the correspondence between the respective configurations of the embodiments and the respective configurations of the present invention. However, the present invention is not limited to the configurations of the embodiments, and the functions described in the claims or the configurations of the embodiments are not limited thereto. Any configuration may be used as long as the function can be achieved.
[0114]
Further, each embodiment or their technical elements may be combined as needed.
[0117]
【The invention's effect】
In the optical apparatus having the image blur prevention device of the present invention, the operating range of the image blur prevention means is changed according to the resolution (recording format). Even if changes occur, the degree of the effect can always be kept within the allowable range, and the deterioration of the image can be prevented.is there. Further, according to the present invention, since the operating range of the image blur prevention means is reduced in accordance with an increase in the focal length, even when the influence of the aberration increases due to the increase in the focal length, This makes it possible to prevent the degree of occurrence of aberration from becoming too large, and to prevent image deterioration..
[Brief description of the drawings]
FIG. 1 is a block diagram showing a main configuration of an apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram for explaining the principle of generation of chromatic aberration.
FIG. 3 is a graph showing a relationship between a conventional focal length and color misregistration.
FIG. 4 is a graph showing a relationship between a color shift and a focal length in the first embodiment of the present invention.
FIG. 5 is a flowchart showing the operation of the apparatus according to the first embodiment of the present invention.
FIG. 6 is a block diagram showing a main configuration of an apparatus according to a second embodiment of the present invention.
FIG. 7 is a graph showing a target apex angle of a conventional blur correction means.
FIG. 8 is a table showing a setting example of each coefficient in the device according to the second embodiment of the present invention;
FIG. 9 is a graph showing a target apex angle in the device according to the second embodiment of the present invention.
FIG. 10 is a flowchart showing the operation of the device according to the second embodiment of the present invention.
FIG. 11 is a block diagram showing a main configuration of an apparatus according to a third embodiment of the present invention.
FIG. 12 is a schematic explanatory diagram of a focus voltage of the automatic focus adjustment device.
FIG. 13 is a setting combination table of each coefficient according to the third embodiment of the present invention.
FIG. 14 is a block diagram showing a main configuration of a modification of the third embodiment of the present invention.
FIG. 15 is a block diagram showing a main configuration of a fourth embodiment of the present invention.
FIG. 16 is a flowchart showing the operation of the device according to the fourth embodiment of the present invention.
FIG. 17 is a block diagram showing a main configuration of a fifth and sixth embodiments of the present invention.
FIG. 18 is a graph showing a relationship between a color shift and a focal length in the fifth embodiment of the present invention.
FIG. 19 is a diagram for explaining the principle of a variable apex angle prism.
FIG. 20 is a diagram for explaining the principle of image blur correction by image blur correction means using a variable apex angle prism.
FIG. 21 is a perspective view showing a variable apex angle prism driving unit.
FIG. 22 is a block diagram illustrating a main configuration of an image blur prevention apparatus using a variable apex angle prism.
FIG. 23 is a sectional view of a variable apex angle prism.
FIG. 24 is a diagram illustrating a lens having a correction optical system.
FIG. 25 is a diagram illustrating a gimbal support structure of the correction optical system.
FIG. 26 is a sectional view of a general zoom lens of a video camera.
FIG. 27 is a diagram for explaining a zoom tracking curve.
FIG. 28 is a block diagram illustrating a main configuration of a zoom lens control system.
FIG. 29 is a diagram illustrating an example of area division for zoom tracking.
FIG. 30 is a diagram illustrating an example of zoom tracking speed setting.
FIG. 31 is a diagram showing a state where a zoom lens and a variable apex angle prism drive unit are combined.
[Explanation of symbols]
1 Focal length sensor
2 Maximum deflection angle data
3 K, θ_Tdata
41 Variable angle prism
45 Microcomputer
150 Aperture encoder
152 Camera processing circuit 153 AF circuit

Claims (2)

An imaging lens having an optical axis;
Imaging means for capturing an image from the taking lens;
Blur detection means for detecting blur,
Image blur prevention means for correcting the image blur by tilting the optical axis by moving,
Means for detecting a resolution in a processing format of an image captured by the imaging means;
Control means for controlling the driving of the image blur prevention means according to the output from the blur detection means;
With
The control means,
When the means for detecting the resolution detects the first resolution, the movable range of the image blur prevention means is set to the first movable range;
When the means for detecting the resolution detects a second resolution higher than the first resolution, the movable range of the image blur prevention means is set to a second movable range smaller than the first movable range. An optical apparatus having an image blur prevention device. A zoom lens having an optical axis;
Imaging means for capturing an image from the zoom lens;
Focal length detecting means for detecting the focal length of the zoom lens,
Blur detection means for detecting blur,
Image blur prevention means for correcting the image blur by tilting the optical axis by moving,
Means for detecting a resolution in a processing format of an image captured by the image sensor;
Control means for controlling the driving of the image blur prevention means according to the output from the blur detection means;
With
The control means,
When the means for detecting the resolution detects the first resolution, the movable range of the image blur prevention means is set to the first movable range;
When the detection result of the resolution detecting means detects a second resolution higher than the first resolution, the focal length detected by the focal length detecting means in the movable range of the image blur preventing means becomes longer. An optical apparatus having an image blur prevention device, wherein the second movable range is set to be smaller than the first movable range according to the following .

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