JPH02287423A - Image blur corrector - Google Patents

Abstract

PURPOSE:To improve operability and image grade by providing correcting means for correcting an image blur in a horizontal direction and perpendicular direction, respectively and varying the oscillation preventive characteristics of the horizontal direction and the perpendicular direction. CONSTITUTION:Sensors are disposed to an inside wall 4 and supporting member 3 of a lens barrel and a torque generator is disposed in the axisymmetric part thereof. The x-axis and y-axis are respectively of the similar constitution; in addition, the x-axis and y-axis are disposed in orthogonal positions. Namely, the correcting means for correcting the image blur are provided in the horizontal direction and the perpendicular direction, respectively and the oscillation preventive characteristics in the horizontal direction and perpendicular direction of the correcting means are so set as to vary from each other. Namely, the horizontal direction (x-axis) where a panning operation is usually frequently executed is set at the function adequate for the panning control and the perpendicular direction (y-axis) where the blurring components are many is set at the function adequate for the oscillation prevention control. The oscillation preventive system having a visually high effect is obtd. in this way.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a device for correcting image blur.

(Description of Prior Art) Imaging devices have been known that have a function of correcting image blur caused by camera shake or the like.

For example, as in US patents USP 2,959,088 and USP 2,829,557, there are systems in which a correction optical system is movably arranged and image blur is corrected by its inertia.

These conventional methods will be explained below.

Figure 1O shows the overall configuration.

In contrast to the main lens 12.13, the lens 1.2 is a correction optical system. The focal lengths of the correction optical systems are set as follows. Let f be the focal length of the lens l with negative power fixed to the lens barrel 4, and f be the focal length of the lens 2 with positive power supported by the movable support 3, then f + = −f! Set the focal length of each lens to satisfy the relationship.

Furthermore, in order to provide movable support on two axes, Gimpal 5 is used to move from the image side focal point of lens 2 at the focal length.

The lens 2 is supported at the position (=-f,).

Additionally, a counterweight is provided to balance the correction optical system.

By satisfying such optical conditions, a so-called inertial pendulum type anti-vibration optical system can be realized.

An explanation of the two-axis movement of the Gimpal 5 will be shown using FIG. 11.

The lens 2 is supported by a support member 5y that has a degree of freedom in the y-axis direction, which is further supported by a support member 5x that has a degree of freedom in the
Supported by

With such a configuration, a correction optical system having degrees of freedom in two axes can be constructed.

Next, the centering (centering) and damping (vibration suppression) operations by the various members attached to the support member 3 will be explained using FIG. 12.

The member 9 attached to the support member 3 is a non-magnetic material such as an aluminum piece, and is suppressed according to the speed by the magnetic effect formed by the magnet (Cfa material) 6 and 7 fixed to the lens barrel 4. A force (damping force) is generated.

Specifically, the eddy current generated by the magnet and the aluminum piece generates a force in a direction that reduces the offset position of the correction optical system from the center of the transverse axis, producing a damping effect.

In addition, the magnets 6 and 7 are attached only to the top of the lens barrel in the drawing, but this is omitted for convenience of explanation, and the bottom and left and right magnets are not shown, but in two-axis control is necessary.

Element lO is a counterweight.

As mentioned above, the pendulum is supported at the focal point of the correction optical system,
A member 10 is installed as a balancer that can maintain balance in a normal stable state.

The attachment is located on the opposite side of the correction optical system 2 across the Gimpal support portion of the support member 3. A member 1 integrally attached to the support member 3 with the counterweight IO
Reference numeral 1 is a magnetic material that performs a centering operation due to the magnetic effect formed between it and a magnet 8 fixed to the lens barrel 4.

The magnetic poles are configured such that the same poles (Ns) face each other and are magnetically repelled. Therefore, since the center of the magnet is aligned with the optical axis (main optical axis) of the main optical system 12.13,
Near the center, a centripetal force (centering force) is generated that causes the correction optical system to align with the main optical axis.

Lenses 12, 13 located further downstream are main lenses and form an image on the final focal plane 14.

Next, the overall operation will be explained.

Let us take as an example the operation of the above-mentioned anti-vibration system in an optical device such as a telescope.

Inside the lens barrel 4 facing the target, the optical image of the target is focused on the focal plane 1 by the main optical system and the correction optical system as described above.
The image is formed on 4.

In the case of a telescope with a high magnification, especially when used handheld, image blur may occur due to camera shake, etc.
Vibration having a frequency component in the range of about 1=1 GHz is generated.

This vibration causes the lens barrel 4, the lens l, and the correction optical system 2.
3.5.9.10.11.

The blurring of the image is corrected by the relative displacement between the lenses 1 and 2.

In such a situation, if a sudden deviation occurs, the above-mentioned damping mechanism suppresses the deviation.

In addition, when there is no blurring, the optical characteristics are better when the center part of the lens 2 is used, so in order to eliminate manufacturing errors and deviations that correspond to DC components in the frequency components of the above deviations,
Near the center, the optical axis of the correction optical system is made to coincide with the main optical axis.

For this purpose, the structure utilizes the above-mentioned centering force.

As described above, when an image is shaken, it is possible to prevent the image from shaking using the pendulum type correction optical system, and the image stabilization characteristics are improved by adding centering and damping using magnetic effects.

(Problems to be Solved by the Invention) However, during actual photography, it is frequently necessary to perform operations such as panning and tilting in order to track the subject or change the subject. On the other hand, the conventional system is a system that only performs vibration-proofing operation, and although it has a vibration-proofing effect against vibrations such as camera shake, it has a vibration-proofing effect regarding the behavior during realistic panning and tilting operations that continuously move in one direction. There were problems in that the image stabilization effect deteriorated, the correction optical system remained largely moved in one direction, and it collided with the inner wall of the lens barrel, resulting in unnatural image movement. .

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems.
In the image pre-correction system, the purpose is to set optimal control functions for X-axis and y-axis operations as a countermeasure against panning, and to realize control of the correction optical system according to the functions. A correction means for correcting the shake is provided in each of the horizontal and vertical directions, and the vibration damping characteristics of the correction means in the horizontal direction and the vertical direction are set to be different, and further,
The vibration isolation area is set wider in the vertical direction than in the horizontal direction.

(Function) Horizontal direction (X-axis) where panning operations are usually performed frequently
is set to a function suitable for panning control, and the vertical direction (y-axis), where there are many components of camera shake, is set to a function suitable for anti-shake control.

(Example) A specific example of the above-mentioned configuration will be explained below.

Torque generating means for controlling the movement of the correction optical system in order to prevent collision with the inner wall of the lens barrel that is likely to occur during operations such as panning and tilting, a control signal generator for controlling the generating means, and a control signal generator for generating the control signal. The main component is a sensor for detecting the movement of the correction optical system as a human input signal for calculation processing.

The above control signal generator provides a non-linear output torque with respect to the swing angle of the inertial pendulum in order to satisfy the two elements of vibration isolation and prevention of excessive movement of the lens unit related to vanning. .

The characteristics of this torque output are shown in FIG.

Near the center, almost no torque is applied to damp the movement of the correction optical system so as not to impede the movement of the inertial pendulum for vibration isolation.

However, when a large movement in one direction is applied, such as when panning, the inertial pendulum lens is configured to generate a large torque to pull it back to the center so that it does not collide with the inner wall of the lens barrel. .

Furthermore, when the torque curve in Fig. 1 is viewed from the axial direction of the pendulum, it gives an image as shown in Fig. 2. Since one concentric circle indicates a predetermined amount of torque change, it can be seen that as one approaches the outer periphery, that is, the end of the lens barrel, the intervals between the concentric circles become closer and the slope of the torque characteristic becomes steeper. In other words, it shows how the torque increases by drawing a nonlinear curve as shown in FIG.

Next, an example of the configuration of the above system will be described.

In FIG. 9, sensors are provided on the inner wall 4 and support member 3 of the 11 pieces, and a torque generator is provided on the axially symmetrical portion thereof. Further, the X-axis and the y-axis have the same configuration, and are arranged at positions perpendicular to each other.

The configuration of the sensor is shown in FIG.

A light emitting element 30 such as an LED attached to the inner wall 4 of the lens barrel
, a power source 34 for the light emitting element, and a PSD that receives the light.
The sensor is made up of a one-dimensional image sensor 32 such as the one shown in FIG.

The slit curtain 31 provided between the light emitting element 30 and the one-dimensional image sensor 32 moves in the direction of the arrow in the figure as the support member 3 of the correction optical system moves, so that the slit curtain 31 is not deflected from the -dimensional image sensor 32. Since a signal corresponding to the angle can be detected, a position signal of the correction optical system can be obtained from the sensor amplifier 33.

Next, the configuration of the torque generator is shown in FIG. 4, taking a voice coil type configuration as an example.

When a control signal is input to the control input terminal 43, a magnetic coupling force (or magnetic repulsion force) is generated between the voice coil 42 and the magnet 41 depending on the amount and polarity of the current.
Torque can be generated in the direction of the arrow in FIG.

Like the sensor, it is arranged so that the X and Y axes are perpendicular to each other, and along with Ginpal support, it is possible to control torque in all directions to dampen the movement of the correction optical system.

Next, FIG. 5 shows an example of a microcomputer-based control system for obtaining a nonlinear curve for controlling vibration isolation, panning, and tilting as shown in FIG. 1.

As mentioned above (regarding X and y), 3G, 31, 32
, 33° 34, the signal from the sensor is sent to the microcomputer 5.
0 is converted into a digital signal by an A/D converter,
It is processed within the microcomputer 50 as deflection angle data.

The processing result is converted into analog data by a D/A converter, and the torque generator configured by 41 and 42 is driven via the torque generator drive circuit 53.

Note that the portions (51, 52) indicated by dotted lines have the same configuration except for the data in the LUT (look up table), and represent the processing contents in terms of hardware.

Next, the internal processing of the microcomputer 50 will be explained below using the flow chart shown in FIG.

Step O1: In order to calculate the control signal in the two horizontal directions, the processing mode i is designated as X.

Step 02: Sensor output θ according to the swing angle of the inertial pendulum
is input as digital data from an A/D converter. This data acts as a spring ring that generates a centering force according to the offset position from the center of the inertial pendulum.

Step 03: Integrate the aforementioned θ to obtain data dl.

This di is for centering, and has the effect of canceling errors caused by various factors such as accumulated errors and manufacturing errors during mass production, and returning the inertial pendulum to the optical axis position.
Since such an integral term has a low degree of influence on the control system, it is not subjected to nonlinear processing like other terms.

Step 04: Differentiate the aforementioned θ to obtain data Δ. This term is a damping term and has an effect on rapid panning, etc.

Step 05: Refer to LUT 1 corresponding to the above-mentioned θ and set it as data "LUT-1." An example of the curve of the function data stored in LUT 2 is converted to the X curve in FIG. 7 or Shown as an X curve.

Step 06: Refer to LUT 2 corresponding to the above-mentioned θ and set data as “LUT-2”. Basically, LUT 1
It has a similar tendency, and depending on the conditions, the l of the LUT
and LUT 2 may be the same function.

However, in order to optimize each of the spring ring and damping term described above, it is desirable to set a dedicated table.

Step 07: Multiply the above θ by "LUT-1" and use this as data d2.

Step 08: Multiply the above Δ by -LUT-2'' and use this as data d3.

Step 09: The above data di, d2. Add d3 and store it as "DATA".

This data is the general control function of the servo loop expressed by the following equation:

DATA = kl umbrella θ + k2* dθ/d
t+l θdtThe above kl and k2 are coefficient data stored in advance in the LUT in the microcomputer. This is based on the characteristics shown in FIG. 7 or 8, refers to a coefficient table of torque control values corresponding to the deflection angle, and selects coefficient data corresponding to the deflection angle.

Step IO: Determine whether the current processing mode i is related to X or y.

If it is an odd number of times, it is related to X (n.

) Return to step 02 through steps 11 and 12, and then.

Processing related to y to calculate vertical control data
Follow the same procedure.

If it is an even number, it is related to y (in the case of YES), and the output processing of steps 13, 14 and 15 is performed.

Step 11 + Store the calculation result "DATA" in Dx as horizontal control data.

Step 12: Change the processing mode i to y and return to step 02.

Step 13: Store the calculation result "DATA" in Dy as vertical control data.

Step 14: Output data "Dx'" from the D/A converter.

Step 15: Output data "Dy" from the D/A converter.

Step 16: As (Determine whether it is okay to end the anti-vibration operation. If it ends (if yes), proceed to the end; if it continues (if no), return to step 01 and end the above process. Repeat until.

In this manner, the generated control data for the torque generator is converted into an analog signal, which is output to the torque generator described above to perform control based on the characteristics shown in FIGS. 7 and 8.

Further, the correction optical system that has been moved to a position close to the inner wall of the lens barrel is returned to the center position by the magnetic force of the magnet 41 of the correction optical system and the magnet 42 on the fixed part side in FIG. 9 during panning and tilting operations. Ru.

In this way, the torque required to return the pendulum toward the center as described above is a measure against large movements such as panning, but it has a negative effect on the original purpose of vibration isolation, and from this point of view, it is better to use less torque. is good.

However, assuming that a consumer camcorder is used, it is known that the frequency of panning operations in the horizontal direction is usually high, but the frequency of tilting operations in the vertical direction is low.

Furthermore, it has been found from measurement data that amateurs experience slightly more camera shake in the vertical direction than in the horizontal direction.

Therefore, the above-mentioned non-linear characteristics are made suitable for a beburning operation in which the X-axis is compared to the Y-axis in accordance with the usage situation of the camcorder. On the other hand, the y-axis is made more suitable for the vibration damping effect than the x-axis.

In other words, the way in which torque is applied to return the object to the center on the vertical axis is weakened relative to the horizontal axis. This situation is illustrated in FIG. 7, and FIG. 8 is an image diagram showing this as seen from the optical axis direction.

These characteristics can be realized by changing the nonlinear characteristic data of the LUT in FIG.

By adopting the configuration as described above, it is possible to stabilize the image during panning and improve the characteristics during image stabilization, as shown in FIGS. 7 and 8 using the LUT data.

(Effect of the invention) Since the X-axis and the y-axis can be optimized for numerical purposes, the above-mentioned conventional problems can be solved, and the limited correction of the correction optical system can be made. It has become possible to create a vibration isolation system that can effectively utilize the deflection angle and has an extremely high visual vibration isolation effect.

When the present invention, which can be used with good optical characteristics at the center of the optical axis and does not require switching operations between camera shake and pan, is applied to consumer videos, it is possible to use it with good optical characteristics at the center of the optical axis. This has the effect of significantly improving operability and image quality because it can be adapted to various usage situations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 9 are diagrams for explaining the present invention in detail, and FIGS. 10 to 12 are diagrams for explaining a conventional example. Figure 1: Nonlinear function with the same xy characteristics Figure 2: Diagram of Figure 1 viewed from the optical axis direction 3 factors: Configuration diagram of the sensor Figure 4 Configuration diagram of the torque generator Figure 5 Two The configuration of the torque generator Overall electrical configuration diagram Figure 6: Explanation of microcomputer operation Figure 7: Nonlinear functions with different characteristics in x and y Figure 8: View of Figure 7 from the optical axis direction Figure 9 Mechanical diagram of the two embodiments Overall configuration diagram Figure 1O: Overall configuration diagram of conventional example Figure TI: Partial diagram for explaining gimbal support Figure 12:
Partial diagram for explaining magnetic effect - Part 1 - Figure 1

Claims (2)

[Claims] (1) An image blur correction device, wherein correction means for correcting image blur is provided in each of the horizontal and vertical directions, and the image stabilization characteristics of the correction means are set to be different in the horizontal and vertical directions. (2) The vibration isolation device according to claim (1), wherein the vibration isolation area in the vertical direction is set wider than in the horizontal direction.