JPH0636571B2 - Imaging device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographing device such as a video camera used in combination with a recording device such as a video tape recorder, and in particular, a stable image can be displayed regardless of rocking of the photographing device. The present invention relates to an image pickup apparatus having an image stabilization function that can be obtained.

2. Description of the Related Art In recent years, the performance of video equipment has been remarkably improved, and high-quality images have become extremely easy to obtain. Along with this, sophisticated photography techniques are required. One of them is shooting from a place where a stable image cannot be conventionally obtained, for example, a moving car, an aircraft, a horse, etc. And for that purpose,
There has been proposed an image pickup apparatus having a vibration isolation function capable of obtaining a stable image regardless of the swing of the photographer and the image pickup apparatus.

Hereinafter, a conventional imaging apparatus having a vibration isolation function will be described with reference to the drawings. FIG. 10 is a block diagram of a conventional imaging device having a vibration isolation function. An image pickup unit 701 includes a lens unit and an image pickup device. Reference numeral 702 denotes a counterweight for the image pickup unit 701, which is mechanically coupled to the image pickup unit 701 by a connecting rod 703. 705 is a joint, which is a connecting rod 7
03 and support rod 704 are rotatably connected. The photographer operates the photographing apparatus by supporting the supporting rod 704. In the above-mentioned structure, the movable unit 7 including the image pickup unit 701, the connecting rod 703, and the counterweight 702 is used.
The counterweight 702 is adjusted so that the center of gravity G of 06 is located near the joint 705. Then, the movable part 706 has a large moment of inertia around the joint 705. Therefore, even if the support bar 704 supported by the photographer suddenly tilts for some reason, the posture of the movable section 706, that is, the image pickup section 701 is kept constant without tilting due to the action of the moment of inertia of the movable section 706. . That is, a stable image can be obtained even when shooting is performed in a place where the photographer swings as described above. John Jurgens; Steedicam Design; SMP TEE Report, Vol. 87, September 1978.
Page 587 (John Jurgens "Steadicam as a Desi
gn Problem ”, SMPTE jounal Vol. 87, Sep, 1978,
P587) etc. are the prior art.

Problems to be Solved by the Invention However, in this conventional example, there is a problem in that the anti-vibration characteristics are fixed. That is, even if the shooting conditions change, it is difficult to change the image stabilization characteristics accordingly. For example, when a photographer holds an image capturing device and photographs while walking, a screen blur occurs in a cycle in which the photographer goes to the foot. On the other hand, when the photographer shoots from above the automobile or helicopter, screen blurring occurs depending on the road surface condition and the rotation speed of the engine. The former and latter have different periods of screen blurring.If the device shown in the conventional example has anti-vibration characteristics so that screen blurring can be suppressed under the former shooting conditions, the image stabilization will occur under the latter shooting conditions. Although the effect of can be obtained sufficiently, the photographing device cannot respond quickly to the operation of the photographer, which causes a problem in operability. On the contrary, if the anti-vibration characteristics are selected so as to suppress the screen shake under the latter photographing condition, the effect of the vibration proof cannot be sufficiently obtained under the former photographing condition. As described above, in the image pickup apparatus having this type of image stabilization function, the element of suppressing the screen blur and the element of the quick response to the operation of the photographer are in conflict with each other.
It is desirable that the image stabilization characteristics for suppressing the screen blur can be changed according to the shooting conditions.

The present invention has been made in view of the above points, and an object of the present invention is to provide an image pickup apparatus capable of changing the image stabilization characteristic in accordance with the image pickup conditions.

Means for Solving the Problems The device of the present invention includes a lens barrel including a lens unit and an image sensor, a support for rotatably supporting the lens barrel, and a lens barrel and a support according to supply power. An actuator means for generating a rotational force between the lens barrel, an inertial angular velocity detection means for detecting an inertial angular velocity of the lens barrel, a relative angle detection means for detecting a relative positional relationship between the lens barrel and the support, and an inertial angular velocity detection Means for synthesizing the output signal of the means and the output signal of the relative angle detecting means, a driving means for supplying electric power for causing the actuator means to generate a rotational force proportional to the synthesized signal of the synthesizing means, and a panning operation instruction. The above-described object is achieved by providing the switch means and the relative ratio variable means for changing the relative ratio of the detection gain of the inertial angular velocity detection means and the detection gain of the relative angle detection means according to the switch means. Of.

With the above configuration, the present invention realizes an electro-mechanical anti-vibration function, and the photographer can change its anti-vibration characteristics according to the photographing conditions by the switch means and the relative ratio varying means. It is possible.

Embodiment An embodiment of the photographing apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, a lens barrel section 101 is shown. The lens barrel section 101 is a lens section 102 for converging light from a subject, and an image sensor 1 for converting an optical image into an electric signal.
It consists of 03 and. Reference numeral 104 denotes a support body that rotatably supports the lens barrel portion 101 around a rotation axis 105, and the operation of the photographing apparatus is performed via the support body 104. 106 is the lens barrel 1
It is an actuator that generates a rotational force around the rotation axis 105 between 01 and the support 104. Reference numeral 107 denotes an inertial angular velocity detection element that is attached to the lens barrel portion 101 and detects an inertial angular velocity of the lens barrel portion 101. Reference numeral 108 denotes an inertial angular velocity detection element that processes an output signal of the inertial angular velocity detection element 107 and outputs an inertial angular velocity signal. It is a vessel. Reference numeral 109 is a relative angle detecting element for detecting a relative angle between the lens barrel 101 and the support 104, and 110 is a relative angle detector for processing an output signal of the relative angle detecting element 109 and outputting a relative angle signal. Reference numeral 111 denotes a gain switching signal generator whose output signal becomes active when the operator of the photographing apparatus instructs a panning operation. 112 and 113 switch the inertial angular velocity detection gain and the relative angle detection gain, respectively, according to the output signal of the gain switching signal generator 111. The output signal of the inertial angular velocity detector 108 that has passed through the angular velocity detection gain switch 112 and the relative angle detector 110 that has passed through the angle detector switch 113.
The output signals of are combined by the combiner 114. 115 is synthesizer 1
Actuator 106 in response to the signal synthesized by 14
Is a driver that supplies electric power to the.

Next, the operation of each component will be described. First, FIG. 2 shows a specific configuration of the inertial angular velocity detecting means, which includes an inertial angular velocity detecting element 107 and an inertial angular velocity detector 108.
Consists of. The forced vibration circuit 201 has a sine wave oscillating circuit of a predetermined frequency, and an inertial angular velocity detecting element is generated by the oscillating signal.
The drive element 202 made of 107 piezoelectric elements is vibrated forcibly. Since the sense element 203 made of a piezoelectric element is arranged in mechanical contact with the drive element 202, it vibrates at the same frequency as the drive element 202. At this time, when the lens barrel 101 rotates about the rotation axis 105 in the inertial coordinate, a Coriolis force of a magnitude proportional to the inertial angular velocity of the lens barrel 101 is generated in the sense element 203 at the same frequency as the forced vibration. To do. The Coriolis force causes mechanical strain in the sense element 203, and an electric signal is generated by a piezoelectric action. If the output of the sense element 203 is synchronously detected by the synchronous detection circuit 204 at the same frequency as the forced vibration and smoothed by the low-pass filter 205, a signal a proportional to the angular velocity of inertia of the lens barrel 101 around the rotation axis 105 is obtained. can get.

FIG. 3 shows a specific structure of the relative angle detecting means, which includes a relative angle detecting element 109 and a relative angle detector 110.
It consists of and. The relative angle detection element 109 is a Hall element and is attached to the support 104. This relative angle detector 1
A magnet 116 is arranged on the side of the lens barrel portion 101 facing the 09, as shown in FIG. 4 (a). And the magnet 116 is the support 104
And a magnetic field corresponding to the relative angle of the lens barrel 101 is generated on the relative angle detecting element 109 (FIG. 4 (b)).
Then, by the action of this magnet 116, the relative angle detecting element 1
A voltage proportional to the product of the current flowing from the input terminal Y to Y ′ and the strength of the magnetic field applied to the relative angle detecting element 109 is generated at the output terminal XX ′ of 09. In FIG. 3, the current flowing from the input terminal Y to Y ′ of the relative angle detecting element 109 is fixed by the current limiting resistors 206 and 207, so that the output terminal X
The voltage generated at X'is proportional to the strength of the magnetic field. That is, the relative angle between the lens barrel portion 101 and the support 104 can be detected by detecting the voltage generated at the output end XX '. The relative angle detector 110 is an operational amplifier.
A differential amplifier composed of 208 and resistors 209, 210, 211 and 212, which differentially amplifies the output of the relative angle detection element 109 by a predetermined factor to obtain an output signal b.

FIG. 5 shows a specific configuration of the gain switching signal generator 111, the angular velocity detection gain switching device 112, the angle detection gain switching device 113, and the combiner 114. The gain changeover signal generator 111 is composed of a changeover switch 213. When the photographer intentionally changes the screen by operating the photographing apparatus (hereinafter referred to as panning operation), the changeover switch 213 is in the state shown in FIG. (+ 12V side) and change the switch 213 from + 12V side to the ground side when you want to suppress the screen blur caused by the shaking of the shooting device, etc., other than during panning operation. Therefore, the output signal of the gain switching signal generator 111 is + 12V when the panning operation is performed, and is the ground potential otherwise. The angular velocity detection gain switch 112 is a gain switching signal generator.
A solenoid 214 driven by the output signal of 111,
It consists of a relay contact 215 that is switched by the electromagnetic force generated in the solenoid 214, and resistors 216 and 217. The angle detection gain switch 113 has the same configuration as the angular velocity detection gain switch 112, and includes a solenoid 218, a relay contact 219, resistors 220, 221.
Consists of. The output signal of the gain switching signal generator 111 is + 12V
State, that is, when instructing the panning operation,
The output signal a of the inertial angular velocity detector 108 is guided to the combiner 114 via the resistor 216. Conversely, when the output signal of the gain switching signal generator is at ground potential, relay contact 215 switches,
The output signal a of the inertial angular velocity detector 108 is guided to the combiner 114 via the resistor 217. The operation of the angle detection gain switch 113 is similar, and when the panning operation is instructed, the output signal b of the relative angle detector 110 is guided to the combiner through the resistor 220, and in the opposite case through the resistor 221. Guided to the synthesizer. The combiner 114 consists of an operational amplifier 223 and a resistor 222,
The currents Ia and Ib flowing into the input terminal are added, and an output signal c proportional to the sum is output.

FIG. 6 shows a specific structure of the driver 115, which is composed of an operational amplifier 225, driving transistors 226 and 227, and a current detection resistor 228. The output signal c of combiner 114 is applied to the non-inverting input terminal of operational amplifier 225. The operational amplifier 225 operates so as to equalize the potential of the non-inverting input terminal and the potential of the inverting input terminal, that is, the voltage generated in the current detection resistor 228 by the current flowing through the coil 229 of the actuator 106. Therefore, the actuator 106
A current proportional to the output signal of the combiner 114 flows through the coil 229 of the.

FIG. 7 shows a concrete structure of the actuator means. The magnet 230, the coils 229 (a) and 229 (b), and the back yokes 231 (a) and 231 (b) made of a ferromagnetic material are provided. It is arranged around the rotating shaft 105. Magnet 230 is back yoke 231
It is connected to the lens barrel 101 via (a) and is magnetized as shown in FIG. 7 (b). On the other hand, the coils 229 (a) and 229 (b) are coupled to the support 104 via the back yoke 231 (b),
The coils 229 (a) and 229 (b) are arranged as shown in FIG. 7 (c). Now, when an electric current flows through the coils 229 (a) and 229 (b), an electromagnetic force is generated between the magnet 230 and the coils 229 (a) and 229 (b), and under the configuration of FIG. A rotating force is generated around the axis 105 according to the magnitude of the current.

Next, the image stabilizing function of the image pickup apparatus of the present invention will be described.
When the angle θ _m around the rotation axis 105 of the lens barrel 101 as viewed from the inertial coordinates, the inertial angular velocity as ω _m , and the angle of the support 104 also as viewed from the inertial coordinates as θ _o , the configuration of FIG. A control block diagram of the image stabilization function of the image pickup apparatus is as shown in FIG. The relative angle θ _o −θ _m between the lens barrel 101 and the support 104 is detected by the relative angle detection element 109. Relative angle detection element 1
09, relative angle detector 110, angle detection gain switch 113
Is represented by block 301 in FIG. 8 and the relative angle θ _o −
A signal b ′ that is B times θ _m is obtained. The inertial angular velocity ω _m of the lens barrel 101 is calculated by the inertial angular velocity detecting element 107 and the inertial angular velocity detector 108.
Detected by. The inertial angular velocity detection element 107, the inertial angular velocity detector 108, and the angular velocity detection gain switching device 112 obtain a signal a ′ that is A times the inertial angular velocity ω _m of the lens barrel portion 101, which is represented by block 302. The influence of the low-pass filter 205 used for smoothing can be ignored by appropriately selecting its pass frequency band). The signals a'and b'are added and combined at the addition point 303 (combiner 114) to obtain the signal c. The driver 115 and the actuator 106 are represented by a block 304, and a rotational force T _a proportional to the magnitude of the output signal c of the combiner 114 is applied to the lens barrel 101 and the support 105.
Occurs during. Here, g _m is the voltage-current conversion gain of the driver 115, and k _t is the torque constant of the actuator 106. A block 305 represents transmission from the rotational force _Ta to the angular velocity ω _{m due} to the mechanical moment of inertia J _m of the lens barrel 101, and a block 306 represents a relationship between ω _m and θ _m . Here, S means the Laplace operator.

Now, if D = B · g _m · k _t / J _m …… (1) F = A · g _m · k _t / J _m …… (2), from the angle θ _o of the support 104, the lens barrel The transfer function of the part 101 to the angle θ _m is G (s) = θ _m (s) / θ _o (s) = D / (S ² + F · S + D) (3) Here, when setting ω ₁ = 2π · f ₁ = D / F …… (4) ω ₂ = 2π · f ₂ = F …… (5), ω ₁ << ω ₂ …… (6) There is. Therefore, the broken line approximate Bode diagram of the frequency transfer function G (jω) is as shown in FIG. That is, the transfer characteristic G (jω) of the angle θ _m of the lens barrel 101 with respect to the angle θ _o of the support 104 viewed from the inertial coordinate is the first breakpoint frequency f.
_It becomes 1 (0 dB) in the frequency range of ₁ or less (line), and attenuates at -6 dB / oct (line) in the frequency range of f ₁ or more and the second corner frequency f ₂ or less (line), and frequency of f ₂ or more. In the range, it is attenuated by -12 dB / oct (line). From FIG. 9, the amount of transmission from the vibration of θ _{o to} the vibration of θ _m becomes small in the frequency range of f _{1 and} above. The degree is 0
It is represented by the difference Z between the dB (line) and the characteristic line.

On the other hand, the quick response of the photographing device to the operation of the photographer is largely influenced by the _first break point frequency f ₁ . The response time to the operation of the photographer is approximately proportional to the reciprocal of f ₁ . Therefore, it is difficult to achieve both the anti-vibration effect and the quick response.

Therefore, the first break point is set in a shooting condition in which importance is attached to the quick response rather than the effect of image stabilization (for example, when the subject is moving, panning, or the like, in which the photographer intentionally moves the angle of view). The frequency is set high (f ₁ ′), and the characteristics are represented by lines, lines, and lines in FIG. 9, and conversely, under the shooting conditions where the effect of image stabilization is important, the image stabilization effect Z is large. The first break frequency is set to be low (f ₁ ) so that the characteristics are represented by lines, lines, and lines.

Now, the first breakpoint frequency is f ₁ and the second breakpoint frequency is f ₁ .
When the _2, the inertial angular velocity detection gain A, and the relative angle detection gain B, the first corner frequency is f _{1 ',} the second break frequency is f _2' when the, the inertial angular velocity detection gain Assuming that A ′ and the relative angle detection gain are B ′, f ₁ B / (2π · A) …… (7) f ₂ A · g _m · k _t / (2π · J _m ) …… (8) f ₁ ′ B ′ / (2π · A ′) (9) f ₂ ′ A ′ · g _m · k _t / (2π · J _m ) ... (10). Therefore, A ′ and B ′ are A ′ = (f ₂ ′ / f ₂ ) · A (11) B ′ = (f ₂ ′ / f ₂ ) · (f ₁ ′ / f ₁ ) · B ……… (12).

In this embodiment, when the changeover switch 213 of the gain switching signal generator 111 is on the ground side, the gain of the inertial angular velocity detector 108 or the resistance value of the resistor 217 is adjusted so as to be the inertial angular velocity detection gain A. The gain of the relative angle detector 110 or the resistance value of the resistor 221 is adjusted so that the relative angle detection gain becomes B, and then the resistance value of the resistor 216 is changed to the resistance 217.
(F ₂ / f ₂ ′) times the resistance value of the resistor 220, the resistance value of the resistor 220 is (f ₂ / f ₂ ′) × (f ₁ /
f ₁ ′) times the gain switching signal generator 1
By switching the changeover switch 213 of 11 to the + 12V side, the inertial angular velocity detection gain can be set to A'and the relative angle detection gain can be set to B '. That is, when the photographer attaches importance to quick response, the switch 213 of the gain switching signal generator 111 is set to +12.
When the panning operation is instructed on the V side and, on the contrary, the effect of the image stabilization is emphasized, the above-mentioned object can be achieved by setting the changeover switch 213 to the ground side.

Next, preferable settings of the inertial angular velocity detection gain and the relative angle detection gain will be described. The relative ratio of the relative angle detection gain and the inertial angular velocity detection gain when the panning operation is instructed is set to be twice or more larger than the relative ratio when the panning operation is not instructed. That is, B ′ / A ′> 2 × B / A (13) By substituting the above equations into the equations (7) and (9) and substituting, 2π × f ₁ ′> 2 × 2π × f ₁ (14). The first break point frequency in the characteristic diagram of FIG.
Corresponding to the quick response is as described above, and by setting the relative ratio of each detection gain as shown in equation (13), the image stabilization characteristics are changed according to the shooting conditions, and the image stabilization effect is It is possible to achieve the object of the present invention to achieve both high speed and quick response.

As described above, the present invention is provided with the switch means for the photographer to instruct the panning operation, and the relative ratio variable means for changing the relative ratio of the relative angle detection gain and the inertial angular velocity detection gain. In an image pickup apparatus having an image stabilization function capable of obtaining a stable image regardless of the vibration of the support of the image pickup apparatus, the image stabilization characteristics can be easily switched according to the shooting conditions.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of an image pickup apparatus of the present invention, FIG. 2 is a diagram showing an inertial angular velocity detection element and an inertial angular velocity detector, and FIG. 3 is a diagram showing a relative angle detection element and a relative angle detector. FIG. 4 is a diagram showing the arrangement of relative angle detection elements, FIG. 5 is a diagram showing a gain switching signal generator, an angular velocity detection gain switching device, an angle detection gain switching device, and a combiner, and FIG. 6 is a driving device. FIG. 7, FIG. 7 is a view showing an actuator, FIG. 8 is a block diagram of the present invention, and FIG. 9 is a view from the angle θ _o of the support to the angle θ _{m of the} lens barrel in the block diagram of FIG. FIG. 10 is a configuration diagram of a conventional imaging device showing Bode diagram showing transfer characteristics. 101 ... Lens barrel, 102 ... Lens section, 103 ... Imaging element, 104 ... Support, 105 ... Rotation axis, 106 ... Actuator, 107 ... Inertial angular velocity detection element, 108 ... Inertial angular velocity Detector, 109 …… Relative angle detection element, 110 …… Relative angle detector, 111 …… Gain switching signal generator, 112 ……
Angular velocity detection gain switching device, 113 …… angle detection gain switching device, 114 …… combiner, 115 …… driver.

Claims (1)

[Claims] 1. A lens section for optically forming an image of light from a subject, an image pickup element for converting an optical image obtained by the lens section into electrical information, and the lens section and the image pickup element mechanically. A lens barrel portion that is coupled to form an optical axis, and a support body that rotatably supports the lens barrel portion with respect to a predetermined rotation axis.
Actuator means for generating a rotational force between the lens barrel portion and the support, inertial angular velocity detection means for detecting an inertial angular velocity of the lens barrel portion around the rotation axis, the lens barrel portion and the support Relative angle detecting means for detecting the relative positional relationship of the body, combining means for combining the output signal of the inertial angular velocity detecting means and the output signal of the relative angle detecting means, and a rotational force proportional to the combined signal of the combining means. The actuator means is provided with driving means for supplying electric power to be generated, and a first state is provided with an operation switch corresponding to anti-vibration photography and a second state is provided for panning photography, and inertial angular velocity detection in the first state is provided. The output signal A'of the inertial angular velocity detecting means and the output signal B of the relative angle detecting means B in the second state with respect to the combined ratio K = B / A of the output signal A of the means and the output signal B of the relative angle detecting means. ′ Ratio K '= B' / A 'photographing apparatus characterized by greater were more than doubled.