JP3783296B2 - Image pickup apparatus having a camera shake correction function - Google Patents

Description

【００４６】
曲率半径ｒ2は、
ｒ2＝（１００＋１）＊（１．５１６３３−１）＝１００．５１６３３
となる。さて、光軸に平行な光線が高さｙ1で第１の光学レンズ（平凹レンズ）の第１面Ｇ１に入射し、そのままの高さで半径ｒ1の第２面Ｇ２に点Ｐ1で入射する。光線と円筒面での法線が光軸となす角度をｉ1とするとｉ1はこの光線の第２面Ｇ２への入射角である。この光線の屈折角をｉ2とすると
【００４７】
【数２】

【００４８】
近軸光線の近似を用いると、
【００４９】
【数３】

【００５０】
と表わせる。
【００５１】
次に屈折光線が入射光軸となす角をｉ3とすると、
【００５２】
【数４】

【００５３】
となる。更にこの光線が第２の光学レンズ３５における第３面（凸円筒面）Ｇ３に入射する点をＰ2、その高さをｙ2とすると、
【００５４】
【数５】

【００５５】
Ｐ2での、第３面Ｇ３の法線が光軸となす角をｉ4、その曲率半径をｒ2とすると
【００５６】
【数６】

【００５７】
したがって
【００５８】
【数７】

【００５９】
ここで、ｉ4＝ｉ1、すなわち第１の入射面と第２の入射面の法線の傾きが等しく、かつ両レンズ３５と３６の屈折率が等しいとき、この光線は平行な２つの境界面を屈折率ｎ1の媒質からｎ2の媒質に入り、再びｎ1の媒質に戻ったことになり、光線は元の角度を保つことになる。したがって（数１）が満たされれば上式のｉ1の係数が１となり、光線は入射と同じ光軸に平行なまま第２の光学レンズ３５の平面Ｇ７に垂直に入射し、入射角度がそのまま保たれて出射する。したがってこの垂直振れ補正機構部２２Ｙはアフォーカル系を満たす光学系となる。
【００６０】
次に第２の光学レンズ３５（３５Ｂ）の屈折率が第１の光学レンズ３６と異なる場合について考える。
【００６１】
図１０に示すように、凹面を有するレンズ３６の屈折率をｎ1、空気の屈折率をｎ2、第３面Ｇ３の曲率半径をｒ2、凸面を有するレンズ３５の屈折率をｎ3とするとき、これらの数の間に次の関係を満たすように設計する。
【００６２】
【数８】

【００６３】
この場合も上記と同様に（数７）までは成立するが、２つのレンズ３５，３６の屈折率が異なるため、点Ｐ1、Ｐ2での面の法線の傾きが一致しても出射光線が入射光線と平行にはならず、Ｐ2での屈折を調べなければならない。まずＰ2での入射角をｉ5、屈折角をｉ6とすると、
【００６４】
【数９】

【００６５】
従って、Ｐ2を屈折した光線が光軸となす角ｉ7は次のように表わせる。
【００６６】
【数１０】

【００６７】
ここで上式の［ ］内が０となれば、ｉ7＝０となり、屈折した光線は光軸と平行となって、平凸レンズの平面を通過した後も光軸と平行となる。この平行条件は（数８）の条件が満たされれば成り立つので、（数８）が平凸レンズと平凹レンズを組み合せた頂角可変プリズム２２におけるアフォーカルの条件となる。
【００６８】
例えば第１の光学レンズ３６のみを図１１Ａから同図Ｂのようにθだけ垂直方向に可変したときには、頂角をθとする可変プリズムとなり、第１の光学レンズ３６側の光線はαだけ屈折する。したがって、スネルの法則によって、
（ｎ1／ｎ2）sinθ＝sin（θ＋α）
θが限りなくゼロに近いときには、
（ｎ1／ｎ2）θ＝（θ＋α）
∴α＝｛（ｎ1／ｎ2）−１）θ
となる。ここで、第１の光学レンズ３６の屈折率ｎ1を、
ｎ1＝１．５
とすれば、空気の屈折率ｎ2＝１であることから、
α＝０．５θ
となる。これによって、第１の光学レンズ３６を角度θだけ傾斜させると、出射する光軸角を０．５θだけ角度変位させることができる。換言すれば、光軸が垂直方向にαだけ傾いたときには、その傾きの方向とは逆方向に２αだけ第１の光学レンズ３６を傾ければ手振れの光軸を補正できる。
【００６９】
第２の光学レンズ３５Ｂと第３の光学レンズ３８との関係も上述したと同じであって、光軸が水平方向にαだけ傾いたときはその傾きの方向とは逆方向に２αだけ第３の光学レンズ３８を傾ければ光軸を補正できる。その結果、第１と第３の光学レンズ３６，３８を同時に所定角だけ回動させて傾ければ、どのような手振れでもその光軸を補正できる。
【００７０】
したがって図１に示すようにビデオカメラ１０に対する手振れ補正用として振れ補正装置を装着したときには、制御部２４では図１２に示すような補正処理が実行される。
【００７１】
同図のように角速度センサ２３，３３からの振動成分△ｘ，△ｙ,△ｘａ，△ｙａがそれぞれ取り込まれ（ステップ６１，６２）、次にそれらの成分のうち△ｘと△ｘａおよび△ｙと△ｙａの一致、不一致が判定される（ステップ６３）。
【００７２】
一致若しくは近似しているときには手振れとは判定せず、この場合には直前の補正値△ｘおよび△ｙがホールドされる（ステップ６４）。つまり手振れ補正は行われない。
【００７３】
これに対して、両成分が近似していないときには手振れと判断してこの場合には手振れを補正するに足る回動角を得るための制御信号（新しい目標値）△ｘ′，△ｙ′が算出され、算出された適正補正値をもつ回動角制御信号がそれぞれ駆動モータ２７，３０に供給されて、第１の光学レンズ３６が△ｙに相当する分回動されると共に、第３の光学レンズ３８が△ｘに相当する分回動されて手振れによる光軸補正が行われる。
【００７４】
図１３は頂角可変プリズム２２の他の実施態様であって、本例では図４の凹凸関係が逆の円筒面を有する光学レンズ３５，３６，３８を使用した場合である。凹凸面の曲率半径などは図５で説明したのと同じであるから、その詳細な説明は割愛する。
【００７５】
図１において、上述した第２の角速度検出器３３の頭部への装着は、この検出器を付けたヘアーバンド状リングやベルト、ヘッドセット用つる部などを頭部装着手段として使用することができ、これによって検出器と頭部の動きを一体化できる。
【００７６】
また図２に示す検出器本体３３Ａにピンチ、クリップ、マジックテープ、ホック、ひもあるいはベルトなどの装着手段を設け、これを帽子、ヘアーバンド、眼鏡フレームなどに装着して、検出器と頭部の動きを一体化させることができる。
【００７７】
上述した例ではこの発明をビデオカメラに適用したが、これに限らず映画用撮影機やスチルカメラなどの手振れ補正系にも適用できることは明らかである。
【００７８】
【発明の効果】
以上説明したようにこの発明では撮像装置本体のみならず、カメラマンの顔の動きも同時に検出し、これらの振動成分に基づいてカメラマンの意識的な動きか単なる手振れかを判断して手振れ補正手段を制御するようにしたものである。
【００７９】
これによれば、パンやチルト操作のようにカメラマンが意識的に撮像装置を動かしたようなときには手振れ補正が禁止されるため、従来のような戻し揺れがなくなり、手振れ補正機能のない場合の画像と全く同じ画像を収録できる特徴を有する。
【００８０】
カメラマンによる意識的な動きであっても特別なキー操作をする必要がないため、カメラマンはフィールドでの取材活動に専念できるようになり、特に業務用のビデオカメラなどに適用して好適である。
【図面の簡単な説明】
【図１】この発明に係る手振れ補正機能を有した撮像装置を取材用ビデオカメラに適用したときの一実施態様を示す要部の系統図である。
【図２】振れ検出用の角速度センサの一例を示す構成図である。
【図３】ビデオカメラとカメラマンとの関係を示す図である。
【図４】手振れ補正手段としての頂角可変プリズムの一例を示す斜視図である。
【図５】頂角可変プリズムを有する振れ補正装置の要部構成を示す断面図である。
【図６】ピッチング用補正機構部の一例をその上部から見たときの構成図である。
【図７】第１の光学レンズの駆動手段を示す図である。
【図８】第１の光学レンズの正面図である。
【図９】頂角可変プリズムがアフォーカル系であることを示す図である。
【図１０】頂角可変プリズムがアフォーカル系であることを示す図である。
【図１１】手振れ補正時の頂角可変プリズムの説明図である。
【図１２】手振れ補正のための一例を示すフローチャートである。
【図１３】頂角可変プリズムの他の例を示す斜視図である。
【符号の説明】
１０・・・ビデオカメラ、１２・・・光学系、１３・・・ＣＣＤ、２０・・・振れ補正機構部、２２・・・頂角可変プリズム、３５・・・第２の光学レンズ、３６・・・第１の光学レンズ、３８・・・第３の光学レンズ、Ｇ１〜Ｇ４・・・第１〜第４の円筒面、２３，３３・・・角速度検出器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus having a camera shake correction function. Specifically, in addition to the detection means for detecting the shaking of the imaging device body, a detection means for detecting the direction of the cameraman's face is provided, and a camera shake correction function is provided when the cameraman intentionally moves the camera body in the pan or tilt direction. By prohibiting, unintentional shake correction is prevented.
[0002]
[Prior art]
In recent video camera technology, which is an imaging device for consumers, high performance and high functionality are remarkable, and a camera with a camera shake correction function has already become common. Even in broadcast-use video cameras, there is a tendency to include this image stabilization function.
[0003]
When this camera shake correction function is installed in a video camera for news gathering, a camera stand (tripod) can be used to record images with no shake when shooting is not possible under favorable environmental conditions, or when shooting at telephoto. The correction rate for image shake due to such shakes is increased.
[0004]
[Problems to be solved by the invention]
When such a camera shake correction function is installed in a video camera, image shake due to camera shake is eliminated, and it becomes easier to see. However, the conventional camera shake correction tends to correct and suppress even a cameraman's intentional pan and tilt operations.
[0005]
This is because even if the cameraman intentionally moves the video camera aiming at the pan or tilt effect, the camera shake correction function operates and correction is made so that the image on the screen does not move suddenly. When such a camera shake correction is performed, a back swing (commonly called a change) occurs as is well known, and the camera operation is uncomfortable.
[0006]
The ideal operation of the image stabilizer is to correct all shake components that are not intended by the person (cameraman) and to stop the shake of the image. Is to provide an image as intended without performing any correction operation. In this way, unnatural movement can be eliminated.
[0007]
As a solution to this problem, it is possible to discriminate between a shake component to be removed and an intentional pan and tilt motion component that should not be removed by capturing the characteristics of the signal from the vibration detection circuit. However, with this method, it is difficult to clearly distinguish between the intended shake and what is not. For this reason, the amplitude and frequency of shake to be removed are suppressed, but in fact, erroneous correction occurs when intentional panning or tilting is performed.
[0008]
When the camera is intentionally moved, if a push button or the like provided on the camera is additionally operated and shake correction is prohibited while the camera is pressed, the occurrence of back shaking can be avoided. However, this method requires the cameraman to add a new complicated operation in addition to the original operation of the camera, so he cannot concentrate on field coverage activities and is still practical for professional use. hard.
[0009]
Therefore, the present invention solves such a conventional problem, and proposes a video camera suitable for broadcasting business in which there is no sense of incongruity between operation and video.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problem, in the imaging apparatus having the camera shake correction function according to the first aspect of the present invention, at least a first detection that detects a change in the orientation of the imaging apparatus together with the camera shake correction unit that corrects the camera shake. The detection output from the first detection means and the second detection means for detecting a change in the orientation of the photographer's face, and the camera shake correction when both detection outputs are approximated. Control for prohibiting camera shake correction by stopping the driving of the means, and controlling the camera shake correction by driving the camera shake correction means based on the detection output from the first detection means when both detection outputs are not approximate characterized by chromatic and means.
[0011]
In the present invention, a change in the orientation of the imaging apparatus main body is detected by the first detection means, and a change in the orientation of the photographer's face is detected by the second detection means. The control means compares and discriminates these detection outputs . When both detection outputs are approximate, the control of the camera shake correction means is stopped to prohibit the camera shake correction, and when both detection outputs are not approximate, the first detection is performed. Based on the detection output from the means, the camera shake correction means is driven to perform camera shake correction.
[0012]
Specifically, the two detection outputs are compared and discriminated, and the camera shake correction function is prohibited when the two detection outputs are approximate. This is because when the cameraman's face moves in the same direction together with the imaging apparatus body, it can be determined that the imaging apparatus body has also moved in the same direction due to intentional (conscious) movement by the cameraman.
[0013]
Accordingly, when the two detection outputs are not approximate, it is determined that the movement is not conscious by the cameraman due to camera shake, and in this case, the camera shake correction means is controlled based on the first detection output as in the conventional case. Will be.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of an imaging apparatus having a camera shake correction function according to the present invention will be described in detail with reference to the drawings.
[0015]
The camera shake correction means used in the present invention is exemplified by an optical correction means, in particular, a case where the camera shake correction means is constituted by an optical axis angle variable optical mechanism that corrects camera shake by changing the optical axis. In this example, an apex angle variable prism is illustrated as the optical axis angle variable optical mechanism. As an image pickup apparatus, a video integrated camera (video camera) used for coverage is shown.
[0016]
FIG. 1 shows one embodiment of a video camera 10 for coverage provided with a shake correction device (camera shake correction means) having a variable apex angle prism. An object 11 is an image sensor via an optical system 12. In the example, the optical image of the subject is converted into an electrical signal (imaging signal) by the CCD 13 having a two-dimensional configuration. The imaging signal is converted into a composite or component color video signal by the signal processing unit 14 at the subsequent stage and is led to the terminal 15.
[0017]
A shake correction mechanism unit 20 is attached in front of the optical system 12. The shake correction mechanism unit 20 is configured as an adapter and is detachably attached to the video camera 10. Therefore, it is connected to the optical system 12 only when necessary.
[0018]
The shake correction mechanism section 20 has a vertical angle variable prism (optical axis angle variable lens system) 22 composed of first to third optical lenses 35, 36, and 38 mounted in a lens barrel 21 that forms a rectangular tube. It has been. An angular velocity detector (first angular velocity detection means) 23 is attached to the lens barrel 21 to detect vibration caused by a shake (hand shake or the like) of the video camera 10.
[0019]
As shown in FIG. 2, an angular velocity detector (vibration gyro) 23 is an angular velocity sensor 31 that detects a vibration component in the horizontal direction x (yawing and panning direction) and an angular velocity that detects a vibration component in the vertical direction y (pitching and tilting direction). A sensor constituted by the sensor 32 can be used, and the angular velocity sensor 31 is attached to the lens barrel 21 so as to be parallel to the horizontal direction of the video camera 10.
[0020]
A vibration component Δx in the horizontal direction x is detected from the sensor 31, and a vibration component Δy in the vertical direction y is detected from the other sensor 32. These are given to the control unit 24 incorporating the CPU.
[0021]
The first angular velocity detector 23 is for detecting the shaking of the video camera body. In the present invention, in addition to this, a second angular velocity detecting means 33 for detecting the movement of the photographer's face is provided.
[0022]
The second angular velocity detector 33 has the same configuration as that of FIG. 2 and is attached to, for example, a cap H as shown in FIG. Since the hat H is used by being mounted on the head of the photographer K, the movement of the face can be detected by the second angular velocity detector 33.
[0023]
When the video camera is in use, as shown in FIG. 3, the subject 11 is directed toward the viewfinder VF with one eye applied. Therefore, when the cameraman consciously moves the video camera body to perform the pan or tilt operation, the face of the cameraman K also moves in the camera moving direction at the same time.
[0024]
This is because detection outputs (vibration components) Δx, Δy from the first angular velocity detector 23 provided in the main body of the video camera 10 in the case of a cameraman's conscious movement such as panning and tilting operations. The detection outputs (vibration components) Δxa and Δya from the second angular velocity detector 33 from the cameraman side are almost the same or approximate values.
[0025]
On the other hand, the video camera main body slightly moves during imaging of the subject 11 is a movement due to camera shake. In such a case, the face of the cameraman K does not move. Therefore, in this case, the detection output from the first angular velocity detector 23 and the detection output from the second angular velocity detector 33 usually do not coincide.
[0026]
The control unit 24 shown in FIG. 1 determines whether or not these coincide and do not coincide (approximate or not approximate), and when they coincide or approximate, hold the control signals Δx and Δy to the camera shake correction means. . When it is determined that the camera shake is caused by the mismatch, the swing angle of the video camera 10 is calculated from the vibration components Δx and Δy, and the rotation angle is such that the swing angle can be corrected. Control signals Δx ′ and Δy ′ are generated. These rotation angle control signals Δx ′ and Δy ′ are supplied to motor drivers 26 and 29 through corresponding control circuits 25 and 28, respectively, and applied to corresponding drive motors 27 and 30, respectively.
[0027]
Here, the drive motor 27 is a drive motor for rotating the third optical lens 38, and the other drive motor 30 is a drive motor for rotating the first optical lens 36, and is a control signal. The optical lenses 36 and 38 are varied by the rotation angles θx and θy corresponding to the values of Δx ′ and Δy ′.
[0028]
Therefore, the conventional back shake does not occur during panning and tilting operations, and the same panning and tilting operations as a video camera without camera shake correction means can be realized.
[0029]
As described above, the variable apex angle prism 22 includes the three optical lenses 35, 36, and 38, each having two surfaces with respect to the optical axis direction. The surfaces facing each other are configured as curvature surfaces (cylindrical surfaces) having the same radius of curvature, and the non-opposing surfaces are flat surfaces.
[0030]
FIG. 4 shows an example of the variable apex angle prism 22 that satisfies such a relationship. In this example, a cylindrical lens is used instead of a spherical lens. A plano-concave lens is used as the first optical lens 36, a convex-convex lens is used as the second optical lens 35, and a third optical lens 38 is used. A concave flat lens is used.
[0031]
The second optical lens 35 includes a third surface G3 and a fourth surface G4. The fourth surface G4 is a cylindrical surface of curvature that is symmetrical with the third surface G3 and approximates the third surface G3 with positive and negative signs. The first and second convex flat lenses 35A and 35B. And the 2nd optical lens 35 is comprised so that the curvature central axis may be orthogonal to the curvature central axis of the 3rd surface G3. Therefore, this can be configured such that the third surface G3 and the fourth surface G4 of the pair of convex flat lenses 35A, 35B having the same configuration are bonded to each other so that the cylindrical surfaces are orthogonal to each other. Of course, an integral configuration may be used.
[0032]
The first optical lens 36 and the first convex flat lens 35A constitute a vertical shake correction mechanism 22Y, and the third surface G3 has the same sign as the second surface G2 and is approximately similar to the second surface. The cylindrical surfaces are used so that the second surface G2 can rotate in the vertical direction YY 'with the radius of curvature as a rotation fulcrum with respect to the third surface G3. Is stipulated.
[0033]
Similarly, the horizontal shake correction mechanism 22X is configured by the second convex flat lens 35B and the third optical lens 38, and the fifth surface G5 has the same sign as the fourth surface G4, and substantially the same as the fourth surface G4. A lens with an approximate curvature cylindrical surface is used. The orientation of each cylindrical surface is determined so that the fifth surface G5 can rotate in the horizontal direction XX ′ with the radius of curvature as a rotation fulcrum with respect to the fourth surface G4.
[0034]
Furthermore, the total focal length of the first to third optical lenses 35, 36, and 38 is an afocal system, and the conditions for that purpose will be described later. By using the afocal system, there is no influence on the optical image of the subject 11 incident on the optical system 12.
[0035]
The variable apex angle prism 22 shown in FIG. 4 is mounted in a lens barrel 21 as shown in FIG.
FIG. 5 is a cross-sectional view parallel to the vertical axis (Y-Y ′) with respect to the optical axis, and the third surface G3 is the front side at substantially the center of the rectangular tube-shaped barrel 21 having a predetermined length. Thus, the second optical lens 35 is attached and fixed.
[0036]
The first optical lens 36 is attached to the front surface of the second optical lens 35 so as to be rotatable with respect to the vertical direction while maintaining a small gap with the third surface G3. Actually, guide means 39 and drive means 44 as shown in FIG. 6 are provided so that the second face G2 can rotate in the YY ′ direction in parallel with the third face G3.
[0037]
FIG. 6 is an exploded view as viewed from the upper surface side of FIG. 5, and a pair of guide grooves 40, 41 are provided in parallel in the vicinity of both left and right end portions of the third surface G 3 constituting the second optical lens 35. Here, arc-shaped guides 58 and 59 having sliding recesses having a T-shaped cross section are fixed. The guides 58 and 59 protrude from the third surface G3 by a predetermined length, whereby the opposing distance from the second surface G2 can be determined.
[0038]
On the other hand, on the second surface G2 side constituting the first optical lens 36, guide strips 42, 43 having a T-shaped cross section are attached and fixed in a bow shape at positions facing the guides 58, 59. (Refer to FIG. 7) By mounting the projecting ends 42a and 43a in the sliding recesses of the guides 58 and 59, the first optical lens 36 is held at a predetermined gap with respect to the second optical lens 35A. It can be rotated in the −Y ′ direction.
[0039]
Between the first and second optical lenses 35 (35A) and 36 and between the second and third optical lenses 35 (35B) and 38, guide means 39 for rotating in the curvature plane direction, respectively. 49 are arranged with the same curvature center curvature, so that the rotation of the first and third optical lenses 36 and 38 with respect to the second optical lens 35 becomes very smooth. The rotation of the first optical lens 36 does not affect the rotation with respect to the third optical lens 38, and the angle can be adjusted independently of each other. As a result, the rotation angle can be adjusted accurately. Also, the configuration is very simple. In most cases, the load of the guide means 39, 49 is the first and third optical lenses 36, 38. Therefore, the load is lightened, the rotation is smoothed, and the rotation power can be reduced.
[0040]
An example of the drive means 44 for rotating the first optical lens 36 will be described with reference to FIGS. A pinion 45 is attached to the drive motor 46, the pinion 45 is engaged with the rack 47, and the rotational force is transmitted to the first optical lens 36.
[0041]
As shown in FIG. 7, the meshing surface of the rack 47 has substantially the same curvature center as the second surface G <b> 2, and the rack body is attached to the side wall side of the first optical lens 36. As a result, when the pinion 45 is rotated as shown in FIGS. 7 and 8, the first optical lens 36 can be rotated in the rotation direction. FIG. 8 is a view when the first optical lens 36 is viewed from the object side. As is clear from this figure, the first optical lens 36 is rotated by a predetermined angle in the YY ′ direction (vertical direction). Can be moved.
[0042]
Since the same configuration as described above is applied between the second optical lens 35 (35B) and the third optical lens 38, corresponding portions are denoted by corresponding reference numerals. Since the third optical lens 38 is exactly the same in configuration and operation except that it needs to be rotated in the horizontal direction (XX ′ direction) with respect to the second optical lens 35B as shown in FIG. Although the configuration and operation thereof are omitted, the guide means 49 includes guide grooves 50 and 51 and arcuate guides 52 and 53. The drive means 54 is also composed of a drive motor 56, a pinion 55 and a rack 57.
[0043]
Now, with respect to the shake correction mechanism 20 configured in this way, the combined focal length of the vertex angle variable prism 22 included therein is designed to be afocal. The conditions for this are as follows. A description will be given using the first and second optical lenses 35 and 36.
[0044]
It is assumed that BK7 is used as the material of the optical lens, the respective radii of curvature are all equal to R100 mm, and a gap of 1 mm is provided as the facing gap Δ. Then, as shown in FIG. 9, in the variable apex angle prism (tablet lens) of the concave and convex cylindrical surfaces having substantially the same radius and facing each other with a slight gap Δ (refractive index n ₂ = 1.51633), When the radius of curvature is r1, the radius of curvature of the third surface G3 is r2, and the common refractive index of the two lenses 35 and 36 is n1, it is designed to satisfy (Equation 1).
[0045]
[Expression 1]

[0046]
The radius of curvature r2 is
r2 = (100 + 1) * (1.51633-1) = 100.51633
It becomes. A light beam parallel to the optical axis enters the first surface G1 of the first optical lens (plano-concave lens) at a height y1, and enters the second surface G2 of the radius r1 at the point P1 at the same height. If i1 is the angle formed by the normal between the light beam and the cylindrical surface and the optical axis, i1 is the angle of incidence of this light beam on the second surface G2. If the refraction angle of this ray is i2,
[Expression 2]

[0048]
Using the paraxial ray approximation,
[0049]
[Equation 3]

[0050]
It can be expressed as
[0051]
Next, if i3 is the angle between the refracted light and the incident optical axis,
[0052]
[Expression 4]

[0053]
It becomes. Furthermore, if the point at which this light ray enters the third surface (convex cylindrical surface) G3 of the second optical lens 35 is P2, and its height is y2,
[0054]
[Equation 5]

[0055]
Assuming that the angle formed by the normal of the third surface G3 at P2 and the optical axis is i4 and the radius of curvature is r2,
[Formula 6]

[0057]
Therefore [0058]
[Expression 7]

[0059]
Here, when i4 = i1, that is, when the inclinations of the normal lines of the first incident surface and the second incident surface are equal and the refractive indexes of both the lenses 35 and 36 are equal, this light ray is defined as two parallel boundary surfaces. The medium having the refractive index n1 enters the medium n2 and returns to the medium n1 again, so that the light beam maintains the original angle. Therefore, if (Equation 1) is satisfied, the coefficient of i1 in the above equation becomes 1, and the light beam is incident on the plane G7 of the second optical lens 35 perpendicularly to the same optical axis as the incident light, and the incident angle is maintained as it is. Lean and exit. Therefore, the vertical shake correction mechanism 22Y is an optical system that satisfies the afocal system.
[0060]
Next, a case where the refractive index of the second optical lens 35 (35B) is different from that of the first optical lens 36 will be considered.
[0061]
As shown in FIG. 10, when the refractive index of the lens 36 having a concave surface is n1, the refractive index of air is n2, the radius of curvature of the third surface G3 is r2, and the refractive index of the lens 35 having a convex surface is n3. It is designed to satisfy the following relationship between the numbers.
[0062]
[Equation 8]

[0063]
In this case as well, the above holds up to (Equation 7). However, since the refractive indexes of the two lenses 35 and 36 are different, the outgoing ray is emitted even if the normal inclinations of the surfaces at the points P1 and P2 match. It should not be parallel to the incident ray and the refraction at P2 must be examined. First, if the incident angle at P2 is i5 and the refraction angle is i6,
[0064]
[Equation 9]

[0065]
Therefore, the angle i7 formed by the light beam refracting P2 with the optical axis can be expressed as follows.
[0066]
[Expression 10]

[0067]
If the value in [] in the above equation is 0, i7 = 0, and the refracted light beam is parallel to the optical axis, and is parallel to the optical axis after passing through the plane of the plano-convex lens. Since this parallel condition is satisfied if the condition of (Equation 8) is satisfied, (Equation 8) is an afocal condition in the variable apex angle prism 22 in which a plano-convex lens and a plano-concave lens are combined.
[0068]
For example, when only the first optical lens 36 is varied in the vertical direction by θ as shown in FIG. 11A to FIG. 11B, it becomes a variable prism having an apex angle θ, and the light beam on the first optical lens 36 side is refracted by α. To do. Therefore, according to Snell's law,
(N1 / n2) sinθ = sin (θ + α)
When θ is infinitely close to zero,
(N1 / n2) θ = (θ + α)
∴α = {(n1 / n2) -1) θ
It becomes. Here, the refractive index n1 of the first optical lens 36 is
n1 = 1.5
Since the refractive index of air n2 = 1,
α = 0.5θ
It becomes. Thus, when the first optical lens 36 is tilted by the angle θ, the outgoing optical axis angle can be angularly displaced by 0.5θ. In other words, when the optical axis is tilted by α in the vertical direction, the optical axis of camera shake can be corrected by tilting the first optical lens 36 by 2α in the direction opposite to the tilt direction.
[0069]
The relationship between the second optical lens 35B and the third optical lens 38 is also the same as described above. When the optical axis is inclined by α in the horizontal direction, the third is set by 2α in the direction opposite to the direction of the inclination. If the optical lens 38 is tilted, the optical axis can be corrected. As a result, if the first and third optical lenses 36 and 38 are simultaneously rotated by a predetermined angle and tilted, the optical axis can be corrected by any camera shake.
[0070]
Therefore, when the shake correction apparatus is mounted for correcting the camera shake with respect to the video camera 10 as shown in FIG. 1, the control unit 24 executes a correction process as shown in FIG.
[0071]
As shown in the figure, vibration components Δx, Δy, Δxa, Δya from the angular velocity sensors 23, 33 are taken in (steps 61, 62), respectively, and among these components, Δx, Δxa, and Δ A match or mismatch between y and Δya is determined (step 63).
[0072]
When they are coincident or approximate, it is not determined that the camera shake has occurred, and in this case, the immediately preceding correction values Δx and Δy are held (step 64). That is, camera shake correction is not performed.
[0073]
On the other hand, when the two components are not approximate, it is determined that the camera shakes, and in this case, control signals (new target values) Δx ′ and Δy ′ for obtaining a rotation angle sufficient to correct the camera shake are obtained. The calculated rotation angle control signal having the calculated appropriate correction value is supplied to the drive motors 27 and 30, respectively, and the first optical lens 36 is rotated by an amount corresponding to Δy, and the third The optical lens 38 is rotated by an amount corresponding to Δx, and the optical axis is corrected by camera shake.
[0074]
FIG. 13 shows another embodiment of the variable apex angle prism 22, and in this example, the optical lenses 35, 36, and 38 having cylindrical surfaces with the concavo-convex relationship in FIG. 4 reversed are used. Since the radius of curvature of the uneven surface is the same as that described with reference to FIG. 5, the detailed description thereof is omitted.
[0075]
In FIG. 1, the above-mentioned second angular velocity detector 33 is mounted on the head by using a hair band ring, belt, headset vine or the like with this detector as the head mounting means. This allows the detector and head movements to be integrated.
[0076]
In addition, the detector main body 33A shown in FIG. 2 is provided with attachment means such as a pinch, clip, velcro, hook, string or belt, and this is attached to a hat, a hair band, a spectacle frame, etc. The movement can be integrated.
[0077]
In the example described above, the present invention is applied to a video camera. However, the present invention is not limited to this, and it is obvious that the present invention can be applied to a camera shake correction system such as a movie camera or a still camera.
[0078]
【The invention's effect】
As described above, the present invention detects not only the main body of the imaging apparatus but also the movement of the cameraman's face at the same time, and based on these vibration components, determines whether the cameraman's conscious movement is a mere camera shake or not. It is intended to be controlled.
[0079]
According to this, when a cameraman consciously moves the imaging device, such as panning or tilting operation, camera shake correction is prohibited, so there is no back shaking as in the conventional case, and there is no image stabilization function. It has the feature that can record the exact same image.
[0080]
Even if it is a conscious movement by a cameraman, it is not necessary to perform special key operations, so that the cameraman can concentrate on field coverage activities, and is particularly suitable for application to a business video camera or the like.
[Brief description of the drawings]
FIG. 1 is a system diagram of a main part showing an embodiment when an imaging apparatus having a camera shake correction function according to the present invention is applied to a video camera for coverage.
FIG. 2 is a configuration diagram showing an example of an angular velocity sensor for shake detection.
FIG. 3 is a diagram illustrating a relationship between a video camera and a photographer.
FIG. 4 is a perspective view illustrating an example of a vertex angle variable prism as a camera shake correction unit.
FIG. 5 is a cross-sectional view showing a main configuration of a shake correction apparatus having a variable apex angle prism.
FIG. 6 is a configuration diagram of an example of a pitching correction mechanism section as viewed from above.
FIG. 7 is a diagram illustrating a driving unit for the first optical lens.
FIG. 8 is a front view of a first optical lens.
FIG. 9 is a diagram showing that the variable apex angle prism is an afocal system.
FIG. 10 is a diagram showing that the vertex angle variable prism is an afocal system.
FIG. 11 is an explanatory diagram of a vertex angle variable prism at the time of camera shake correction.
FIG. 12 is a flowchart illustrating an example for camera shake correction.
FIG. 13 is a perspective view showing another example of a variable apex angle prism.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Video camera, 12 ... Optical system, 13 ... CCD, 20 ... Shake correction mechanism part, 22 ... Vertical angle variable prism, 35 ... 2nd optical lens, 36. ..First optical lens 38 ... third optical lens G1-G4 ... first to fourth cylindrical surfaces 23, 33 ... angular velocity detector

Claims (6)

At least a first detection unit that detects a change in the orientation of the imaging apparatus together with a camera shake correction unit that corrects camera shake;
Second detection means for detecting a change in the orientation of the photographer's face ;
The detection output from the first and second detection means is compared and determined, and when both detection outputs are approximate, the drive of the shake correction means is stopped and the shake correction is prohibited.
Image stabilizer characterized by chromatic and control means for performing camera shake correction by driving and controlling the camera shake correction means based on a detection output from said first detection means when both detector outputs are not similar An imaging apparatus having   2. The image pickup apparatus having a camera shake correction function according to claim 1, wherein the first and second detection means are constituted by angular velocity sensors. The camera shake correction means is composed of an optical axis angle variable optical mechanism,
2. An image pickup apparatus having a camera shake correction function according to claim 1, wherein the camera shake is corrected by changing the optical axis angle.   2. The image pickup apparatus having a camera shake correction function according to claim 1, wherein the second detection unit is provided in a mounting unit mounted on a head. 5. The image pickup apparatus having a camera shake correction function according to claim 4 , wherein said mounting means uses a hair band ring, a belt, a headset or the like. The camera shake correction means is composed of three optical lenses arranged close to each other, and a first optical lens whose one surface is a cylindrical surface is configured to be rotatable in the vertical direction,
2. An imaging apparatus having a camera shake correction function according to claim 1, wherein a variable vertex angle prism is used in which the third optical lens whose one surface is a cylindrical surface is configured to be rotatable in the horizontal direction. .

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