JP3269706B2 - Camera shake reduction camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reducing image deterioration due to camera shake (camera shake) at the time of photographing, and more particularly to a camera for predicting and detecting camera shake before camera shake exposure to reduce camera shake.

[0002]

2. Description of the Related Art Conventionally, various devices have been proposed for preventing a photographed image from deteriorating due to camera shake. For example, according to JP-A-63-53531 proposed by the present applicant,
At the time of shooting, shutter release is instructed near the peak of camera shake, and exposure is performed. That is, the shutter is driven at the time when the camera shake is minimized to prevent image blurring.

In addition, Japanese Patent Laid-Open No.
In Japanese Patent No. 24620, a camera shake is detected as an angular velocity, and when a camera shake exceeding a preset allowable value occurs after a shutter is opened, a shutter is forcibly closed to suppress image blur. In this conventional example, the shutter is opened when a predetermined allowable value or camera shake is in a decreasing direction.

[0004]

However, in the above-mentioned Japanese Patent Application Laid-Open No. 63-53531, the shutter is released from holding near the peak of the camera shake.
Immediately after the minimum value of the camera shake (the camera shake is increasing)
If the shutter is opened at the same time, the blur during the exposure increases, and as a result, the image quality deteriorates.

In Japanese Patent Laid-Open No. Hei 4-24620, even if the camera shake is below a predetermined allowable value, photographing is prohibited if the camera shake is increasing, and in actual photographing, a shutter chance is missed. become.

Conventionally, when the output of the camera shake detecting means is converted into the size of the camera shake, motions (images) in two orthogonal directions on the screen are detected and synthesized. Can be synthesized by calculating the square mean. However, performing a square root operation in a small device such as a camera complicates the device and leads to an increase in cost.

In addition, such a square average is used to convert vertical, horizontal, and oblique blurring into a uniform size.
The blur in the diagonal direction becomes more conspicuous than in the left and right, and as a result, the impression of the image is deteriorated.

Further, in the case of predicting a blur that would occur during exposure before the shutter is opened, it has been conventionally proposed to predict blurs corresponding to two directions on a screen and to combine them thereafter. However, in this case, the calculation of the prediction is required twice, the amount of calculation is increased, and a high-performance calculator is required. In addition, in order to perform prediction, it is necessary to accumulate past camera shake signals, but this amount is also required to be doubled, which leads to an increase in cost.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a camera shake reduction camera which has a small release time lag and prevents image blurring without losing the timing of permitting the start of exposure.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a camera shake detecting means for detecting a camera shake signal related to a camera shake, and an exposure request by detecting an instruction to start exposure by manual operation of a photographer. An exposure request signal generating means for outputting a signal; and detecting the camera shake when the exposure request signal is generated.
Exposure based on the shake signal output by the means
Means for estimating the amount of camera shake at the center of the
The camera shake signal predicted by the measuring means and the exposure
Ratio with the camera shake limit value set to 1/2 of the shake amount
The shake determining means to be compared and the shake determining means
It was determined that the predicted camera shake amount was below the limit value
An exposure means for performing exposure in a case , in a camera shake reduction camera having a camera shake reduction determination means for determining an increase or decrease direction of the camera shake signal output from the camera shake determination means,
If the camera shake signal determined by the camera shake increase / decrease determination means is in the increasing direction, lower the limit value, and if the camera shake signal is in the decreasing direction, change the camera shake allowable change means to increase the limit value, The present invention provides a camera shake reduction camera characterized by comprising:

[0011]

[Function] With the camera shake reduction camera having the above configuration,
At the time of exposure, camera shake is detected in two axial directions (x, y axes), and the respective absolute values are added to determine the size of the camera shake on the image plane. The presence / absence of camera shake and the direction of increase / decrease of camera shake are detected from the output of the camera shake signal. This detection result, the limit value of the hand shake acceptable is lowered as determined strictly in increasing direction, the Keep decreasing direction changed as raised, there by increasing direction
Even if the exposure is permitted (shutter is released)
In some cases, the magnitude of a realistic camera shake is evaluated and shooting is performed, so that image blurring is reduced.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows a schematic configuration of a camera shake reduction camera according to the present invention and will be described. This camera has a camera shake reduction function. The camera includes a camera shake detection unit 1 that detects a camera shake, and a camera shake increase / decrease determination that detects an increase / decrease direction of the camera shake based on an output signal of the camera shake detection unit. A camera shake permissible limit value setting unit 3 for changing a limit value of an allowable camera shake used in a camera shake presence / absence determining unit 4 based on an output determined to increase or decrease the camera shake, and an output signal of the camera shake detection unit. A camera shake presence / absence determination unit 4 which compares the camera shake signal based on the threshold value with an allowable camera shake limit, determines whether there is a camera shake, and transmits the result to an exposure unit.
And an exposure request signal generating section 5 for detecting an instruction to start exposure by a photographer and outputting an exposure request signal, and an exposure section 6 for exposing a subject image with a predetermined amount of light to a film.

For example, as shown in FIG. 1B, a camera shake detection section 1 includes a camera shake signal detection section 7 composed of a sensor and a camera shake signal prediction section for performing an operation for predicting an output of the output signal after a predetermined time. 8. FIG. 1 (c)
As shown in the figure, an exposure start signal output section 9 for starting exposure when there is no camera shake is provided in the above-mentioned camera shake presence / absence judgment section 4, and the exposure section 10 starts exposure according to this output signal. Can also be configured.

With the configuration shown in FIGS. 1A to 1C, a judgment level for the presence or absence of camera shake is set in accordance with the direction of increase or decrease of camera shake, and if camera shake tends to increase, camera shake is erroneously made. This prevents the determination result that there is no output.

Then, as shown in FIG. 1D, the camera shake is detected in two axial directions by using a vertical camera shake detector 11 and a horizontal camera shake detector 12, and the absolute value of each is calculated. First and second absolute value calculation units 13 and 1 to be obtained
Using 4, the camera shake as the absolute value of each axis is obtained. Thereafter, an adder 15 is provided with a camera shake signal processor 16 for simply adding the absolute values of the respective axes to obtain the magnitude of camera shake on the photographing image plane, and based on the output signal of the camera shake signal processor 16. The presence or absence of camera shake is determined by the camera shake
Nothing is determined. The camera shake reduction unit 18 operates based on the determination result. With such a configuration, the blur in the diagonal direction is evaluated larger than the vertical and horizontal directions, and the more realistic magnitude of the camera shake is easily evaluated to reduce the blur.

Further, as shown in FIG. 1 (e), when a camera shake signal is predicted, the camera shake is detected using first and second camera shake detection sections 19 and 20 which detect the camera shake separately in two orthogonal directions. In the section 21, the first and second camera shake detecting sections 1
After synthesizing the signals from 9 and 20 and converting them into one kind of camera shake signal, the camera shake prediction calculating unit 22 converts the camera shake signal into a predicted camera shake signal indicating the magnitude of the camera shake in the future for a predetermined time. It may be configured by a camera shake presence / absence determination unit 23 that determines the presence or absence of camera shake based on the result, and may be simplified by a prediction calculation.

Next, FIG. 2 shows the structure of a camera shake reduction camera as a first embodiment according to the present invention. Here, as an example of detecting a camera shake signal according to the present invention, a method of detecting a relative angle shift between a photographer's face and a camera proposed by the present applicant in Japanese Patent Application No. 5-64371 is adopted. Detailed description is omitted.

In this camera, the camera shake signal detecting section 7
Is for measuring the amount of tilt between the face of the photographer (not shown) and the rear surface of the camera as shake, and includes an x-axis shake signal detection unit 7a for detecting vertical tilt and a y-axis shake signal detection for detecting horizontal tilt. 7b.

The camera shake signals sequentially detected by the camera shake signal detection section 7 are stored in a camera shake signal storage section 24 composed of a RAM in an x-axis and y-axis camera shake signal storage sections 24a and 24b, respectively. .

The predicted time signal output unit 27 is provided with a photometric device 28 for measuring the luminance of the subject and an exposure amount (shutter speed [exposure second],
The exposure time / aperture value setting unit 29 in the CPU 25 that calculates the exposure aperture value) is provided. The exposure time / time information of the exposure time / aperture value is sent to the camera shake signal readout control unit 26 as predicted time information.

The hand-shake signal read control unit 26 selectively reads out the x-axis and y-axis hand shake signals from the x-axis hand-shake signal storage unit 24a and the y-axis hand-shake signal storage unit 24b based on the predicted time information. Enter 30.

The prediction operation section 30 comprises an x-axis camera shake signal prediction operation section 30a and a y-axis camera shake signal prediction operation section 30b, which are converted into an x-axis prediction camera shake signal and a y-axis prediction camera shake signal, respectively. The converted x-axis and y-axis predicted camera shake signals are converted into 2
It is converted into a value representing the magnitude corresponding to the dimensional shake (synthetic shake signal). The composite shake signal is input to the exposure sequence control unit 32, and the operation of the exposure sequence is determined according to the pressed state of the release switch 33.

The camera shake reducing section 18 shown in FIG. 1 specifically, as shown in Japanese Patent Application Laid-Open No. 5-19327, starts the opening of a shutter for photographing based on a signal indicating camera shake. Exposure sequence control unit 3 for permitting or prohibiting the actual opening and avoiding the timing when the image quality is degraded due to camera shake to enable shooting.
2.

The camera shake signal reading control unit 26, the prediction calculation unit 30, the predicted camera shake signal synthesis unit 31, and the exposure sequence control unit 32 are configured as programs on the CPU 25 in the photographing apparatus.

Next, a description will be given of a camera shake signal of the camera having such a structure. The camera shake signal in the present embodiment is information on an angle, which means the dimension of the position of the image when the camera shake is considered. The magnitude of the deterioration of the image quality due to the shake largely depends on the amount of movement of the subject image during the exposure.

Therefore, in the case of the present embodiment, the difference between the detected camera shake signals at two time points indicates the magnitude of the camera shake. Therefore, when the camera shake is evaluated in the exposure sequence control unit 32, attention is paid to the difference between these two points in time. The magnitude of shake occurring during exposure can be considered as a difference between the position of the image at the start of exposure and the position of the image at the end of exposure.

In the case of an exposure time of about several tenths of a second, it can be considered that the difference between the position of the image at the start of the exposure and the position of the image at the center of the exposure is about twice. In general, in the case of prediction, the longer the prediction time, the longer the signal accuracy may be degraded. Therefore, the latter is often more advantageous when considering the fluctuation during exposure.

In the case of an exposure time of about several tenths of a second, it can be considered that the difference between the position of the image at the start of the exposure and the position of the image at the center of the exposure is about twice. In general, in the case of prediction, the longer the prediction time, the longer the signal accuracy may be degraded. Therefore, the latter is often more advantageous when considering the fluctuation during exposure. The exposure sequence controller 32 in the present embodiment, those expected camera shake amount at the middle point of the exposure, to allow exposure only in the case of 1/2 hereinafter <br/> size of the deflection allowable And

The prediction will be described with reference to FIG. FIG. 3 shows the transition of the camera shake signal when the horizontal axis is time t by a solid line. Assuming that the current time point is t = 0, the camera shake signal is x ₀ , the signal at a time Δt past is x ₁ , and the 2 · Δt past is x
_{Assume 2} . When extrapolating and predicting the transition of the camera shake signal using a quadratic expression, the prediction time is represented by t _y and the predicted value is represented by _xy . The difference between the signals at t = 0 and t = _{ty at} the two time points
Think as.

[0030]

(Equation 1) Here, the coefficients a, b, and c of the quadratic expression are x ₀ , x ₁ , x
About ₂ ,

[0031]

(Equation 2) Can be obtained by solving the simultaneous equations.

[0032]

(Equation 3) Then, _xy is calculated as t _y / Δt = K.

[0033]

(Equation 4) Can be expressed as

When the prediction time is changed, if t _y is changed, the coefficient of each term is changed, the quadratic expression for the prediction is changed, and the characteristics of the prediction are changed. Here, with respect to the equation (5), a calculation output _xy when a sine wave is given to the input will be considered. For example, assuming that a prediction of 30 ms is made, t _y
= 30 ms, Δt = 10 ms, input signal sin2πf ·
Assuming t ( f ; input frequency, t; time), and for simplicity,

[0035]

(Equation 5) Then, the phase advances, that is, under the condition of prediction,

[0036]

(Equation 6) Becomes Here, C is the gain obtained by the calculation of the equation (5), and φ is the phase difference corresponding to the prediction time. FIG. 4 shows a graph of the gain, and FIG. 5 shows a graph of the input frequency with respect to the prediction time. The solid line is the characteristic of the operation obtained by equation (5). As shown in Japanese Patent Application No. 4-11373 proposed by the present applicant, an example in which the values of α, β, and γ in equation (6) are optimized from the actual camera shake signal and calculated. Is indicated by a dotted line. By the way, in the case of equation (5),

[0037]

(Equation 7) For optimization,

[0038]

(Equation 8) It is. From equations (7) and (7 ′), α + β + γ = 1
In the case of (1), it can be seen from the graph that the gain on the low frequency side at 1 Hz or less becomes 1, and the total of α, β, and γ is also set to 1.

By the way, as can be seen from the graph,
The calculation of equation (5) does not have flat characteristics with respect to the gain and the prediction time with respect to the frequency. However, since the frequency component of the camera shake signal is considered to have its main component at about 10 Hz or less, it is important that the prediction calculation characteristics be flat at 10 Hz or less. There is an advantage of the method.

However, by setting the optimum coefficient,
Disadvantages of performing the prediction calculation by reading out according to the prediction time also lead to an increase in the size and cost of a storage device for presetting coefficients for each prediction time and storing them.

Therefore, Δt is changed in order to change the prediction characteristics. When f = 1 Hz, in the case of equation (9), Δt = 0.02 S; A = 0.845, B = 0.148, φ = 0.173
, Prediction time = 27.5 ms Δt = 0.01 S; A = 0.877, B = 0.072, φ = 0.081
, Prediction time = 13.0 ms Δt = 0.005 S; A = 0.884, B = 0.035, φ = 0.040
, The predicted time = 6.4 ms. That is, at f · Δt << 1,

[0042]

(Equation 9) So that

[0043]

(Equation 10) And the prediction time is (φ / 2π) · 1 / f, so the prediction time is proportional to Δt.

That is, by keeping the coefficient for prediction used in the equation (6) constant, and changing the time interval Δt to the past shake signal input, the prediction time changes proportionally. By the way, in this embodiment, since the shake is evaluated as in the expression (1), from the expression (6),

[0045]

[Equation 11] Therefore, it is also possible to simplify the calculation by storing α ′ as a prediction coefficient instead of α as α ′ = α−1 and using it at the time of prediction calculation. In this embodiment,
The basic Δt is 10 msec, and yt is 30 msec. This reference value, respectively Δt _o, and y _to.

Next, the operation of each component of this embodiment will be described with reference to the flowchart shown in FIG. Here, the reference numerals of FIG. 1 and FIG.
First, after the program of the CPU 25 is started, the camera shake data storage number counter M is cleared (Step S).
1) Next, the photometric device 28 is operated to measure the subject brightness (step S2). Next, based on the measured subject luminance, the exposure time at the time of shooting and the aperture value are obtained by a known Apex operation formula (step S3). This calculation program is executed by the aperture value setting unit 29 at the time of exposure.

Next, the occurrence of camera shake is detected as a camera shake signal using the x-axis camera shake signal detector 7a and the y-axis camera shake signal detector 7b of the camera shake signal detector 7 (step S).
4). These detected camera shake signals are RA signals for each of the x and y axes.
It is sequentially stored in the x-axis camera shake signal storage unit 24a and the y-axis camera shake signal storage unit 24b in M24 (step S5). Also, the camera shake data storage number counter M is counted up.

Next, it is determined whether the photographer has operated the release switch 33 for photographing, that is, whether or not the second-stage release switch has been turned on (step S6). If there is no operation (NO), the process returns to the photometry in step S2, and the following is repeated periodically from the photometry. However, when the release switch 33 is operated (YE
S), the previously obtained exposure time is read out (step S7).

Next, time data to be predicted is set (step S8), and it is determined whether or not prediction is possible with this value (step S9). This is also data for checking the accumulated amount of past data required for performing the prediction calculation. As described above, the shake at the center of the exposure time is predicted. However, in the case of exposure in units of seconds, the prediction of the shake at the center of the exposure is very long and it is very difficult to obtain accuracy. In the present embodiment, the limit value of the prediction having practical accuracy is set to 50 ms. That is, the camera shake prevention operates up to the exposure of about 1/10 second. Therefore, の of the value set as the exposure time is compared with the limit value 50 ms, and the smaller one is set as the predicted time ty .

Ty = (exposure second / 2) and the smaller of (limit value) (11) Next, it is determined whether or not there is enough data to be predicted. That is, the value of the hand shake data storage number counter M indicating the circuit storing the data is converted into the storage time based on the storage interval time Δtm, and the ratio between the predicted time ty and the predicted time reference value tyo is converted to the data interval reference value Δto Is compared with twice the image multiplied by, to determine whether the accumulation time is long. If this is expressed by the formula,

[0051]

(Equation 12) Will be examined. here,

[0052]

(Equation 13) And the time interval Δt of the input data input to the prediction calculation is determined (step S10). If the data cannot be predicted due to insufficient data accumulation (NO), the process returns to photometry, and the camera shake detection and storage is repeated.

Next, based on the input data time interval Δt, the camera shake signal used for prediction is stored in the camera shake signal storage unit 2 (R
AM 12) (step S11). That is, x
Axis, y-axis, latest value, Δt past value, 2 · Δt
Reading past values.

Next, a prediction operation is performed (step S1).
2). The predicted camera shake signal on the x axis is d _y , the latest camera shake data is x ₀ , the data at Δt past is x ₁ , the data at 2 · Δt past is x _2, and similarly, the y axis is d _y , y
_0, and y _1, y _2. Further, the prediction coefficients used in the above equation (10) are α ′, β, and γ. Then

[0055]

[Equation 14] Becomes Thus, the magnitude of the shake after the prediction time is obtained. Next, the two axes are combined (step S1).
3). When the shake is considered as a movement vector of the image on the image plane, the magnitude d of the combination is

[0056]

(Equation 15) Is represented as

Next, the presence / absence of a shake is determined by comparing the obtained synthesized hand shake signal d with information Th about an allowable limit value of the shake (step S14). Normally, a shake equal to the allowable scattering circle diameter can be tolerated, and since the predicted combined camera shake signal d indicates the magnitude of the shake at the center of the exposure, it corresponds to Th = 1/30 mm.

When d> Th / 2 (16), it is determined that there is a shake. This Th may be set to a correspondingly large value when the purpose is to remove a large shake peculiar to a beginner.

As a result of the shake determination in step S14,
If it is determined that "there is a shake" (YES), the process returns to the detection of the shake signal described above and the following steps are repeated. However, if the result of the shake determination is “no shake” (NO),
The exposure unit 34 for exposing a known film at a predetermined shutter speed and aperture value is operated to expose the film (step S15). After that, return to the beginning of the program and execute the following again.

Further, the above-described synthesis of the shake around the two axes of the x-axis and the y-axis will be further described. In the above-described embodiment, considering the shake in a vector, the shake on the x-axis is represented by d _x ,
Assuming that the y-axis deflection is d _y ,

[0061]

(Equation 16) It was expressed. However, in a small-scale device such as a camera, it is sometimes difficult to calculate the square root in consideration of the size of the program and the time required for executing the program. Therefore, d _x, the absolute value of _{d y | d x |, |} d y | a, transforming the equation (15).

[0062]

[Equation 17] Here, d = 0 when d _x = d _y = 0, and the above equation is for d ≠ 0. Here we pay attention to the route.

[0063]

(Equation 18) When partial differential with | d _x |

[0064]

[Equation 19]

In the case of the [0065] is, | dx | = | dy | a and, at that time, the Z = 1/2. FIG. 7 shows Z and |
dx |, | dy | Also, | dx
Considering the symmetry of Z with |, | dy |

[0066]

(Equation 20) Has the largest error when | d _x | = | d _y |. However, when x and y are orthogonal to up, down, left and right,
| D _x | = | _dy | is an oblique swing.

By the way, many ordinary subjects have an edge or a linear contrast in the upper, lower, left, and right directions. Therefore, when comparing photographs in which the same amount of image is blurred so as to bleed vertically, horizontally, and diagonally, the contrast of the diagonally blurred photograph is the largest. Therefore, the impression of the deterioration of image quality when viewed photos, of the up-and-down direction
Due to the diagonal shaking that the shaking and the horizontal shaking combined
Bleeding will be felt most strongly.

For example, when the shake in the two-axis direction is detected vertically, horizontally, and the two axes are combined and evaluated, when weighting based on the shake direction is considered, d = │d _x │ + _│dy │. It can be said that the combining operation according to (21) performs this weighting simultaneously with the combining.

Further, the operation time is very simple as compared with the equation (15), and the system is not complicated. Therefore, it is also useful to determine the magnitude of the camera shake using the equation (21).

When combining two-axis shakes, in the above embodiment, the camera shake signals on the x and y axes are separately predicted and then combined. It is also possible to predict this after synthesis. In this case, the shake signal (x, y) on the x and y axes is detected, and the shake speed signal (vx, vy) is obtained from the previous measurement value ( x ', y') and the measurement time interval (Δtm).

[0071]

(Equation 21)

Next, the combined shake signal (v) is obtained as v = | v _x | + | v _y | (23), and the combined shake signal v is stored in a time series. In the prediction calculation, the predicted shake signal is V _y , and the latest shake signal is v
₀ , the signal at Δt time past is v ₁ , the signal at 2 · Δt time past is v ₂ , and α, β, γ are prediction coefficients, and V _y = α · v ₀ + β · v ₁ + γv ₂ (24) Is required.

As described above, since the predicted shake signal _Vy is obtained from the combined value of the shake speeds, it is dimensionally equivalent to the shake speed. Therefore, the exposure time S is multiplied to obtain the magnitude of the shake during the exposure. This product is compared with the allowable limit of the shake (Th). That is, V _y
-It is determined that there is a shake when S> Th.

In the first embodiment, when it is determined whether or not the magnitude of the shake is within the allowable value, the allowable value is fixedly handled in the first embodiment. As well as increasing the accuracy, the opportunity for release can be increased.

FIG. 8 shows an example of a temporal transition of the shake signal d. The section marked with * below the predetermined value Th is the range in which exposure is permitted. At time t _A, and there is an indication of exposure start of the photographer. The magnitude of the shake at that time is A. Allowable value Th
As compared with, since A> th, the release operation is not performed. At time t _B , the shake signal d becomes equal to the allowable value, and the exposure starts. In this manner, the exposure is performed at a timing with a small shake, but it is assumed that the photographer instructs the start of the exposure at the timing of the time t _C.

The shake in this case is C. Since C is equal to or less than the allowable value, the exposure is performed immediately. However, at this timing, the shake is in the increasing direction, and the shake during the actual exposure may exceed the allowable value. In other words, the shake during the exposure is expected before the exposure, and this possibility remains. In the case of the timing t _B is the runout decreasing direction, this possibility is considered low.

Next, an embodiment will be described which reduces the possibility that the shake becomes an unacceptable value during the exposure at the timing t _C. As shown in FIG. 9, the allowable limit Th _d
And a stricter allowable limit value Th _u is set. If the shake signal d is in the decreasing direction, the magnitude of the shake signal d is compared with the allowable value Th _d to determine whether there is a shake. In the vibration signal d is increasing direction section (section in FIG black circle), comparing th _u and d is a tight tolerance limits, determines the presence or absence of vibration. As a result, the range where the actual exposure is permitted is the range of the shake signal indicated by the thick line in FIG.
Exposure in _C is prohibited, and the range in which there is a possibility of shake can be accurately prohibited.

As a second embodiment according to the present invention, referring to the flowchart shown in FIG. 10, the shake speed is obtained by setting the tilt of the camera due to the shake of the two axes x and y as (x, y) and determining the shake speed. Combining, storing in chronological order, using the stored data to predict the shake that would occur during exposure,
The operation of the camera that determines the presence or absence of a shake at an allowable limit of a different shake based on the direction of increase or decrease of the signal and permits or prohibits exposure will be described.

First, a camera shake data storage number counter M indicating the number of combined camera shake signals stored in the camera shake signal storage unit is cleared (step S21). Then, the subject brightness is measured using the photometric device 28 (step S2).
2).

Next, using the exposure time / aperture value setting section 29, the exposure time (S) used for proper exposure and the aperture value are calculated from the subject luminance (step S23). Further, the camera shake signals on the x and y axes are detected (step S2).
4).

Let the deflection angle of the x axis be x and the deflection angle of the y axis be y
And then, then calculated according the aforementioned (22), swing velocity _v v, it determines the y _y (step S25). Next, the previous shake detection value (x ′,
y ′) is replaced with the latest camera shake detection value as x ′ = x, y ′ = y (step S).
26).

Next, the camera shake speed is synthesized according to the equation (23) to obtain a synthesized camera shake signal (step S27), and the obtained synthesized camera shake signal is stored in the camera shake signal storage unit 24 (step S28).

Next, the release switch 33 by the photographer
Is detected (step S29). That is, if there is no operation until the second-stage release switch is turned on (NO), the process returns to the photometry in step S22.
If there is a release operation (YES), the exposure time is read out as in the first embodiment (step S30), time data to be predicted is set (step S31), and it is determined whether prediction is possible (step S31). Step S32). When the prediction cannot be made by this determination (NO), the process returns to the photometry in step S22. If the prediction can be made by this determination (YES), as in the first embodiment, the address of the camera shake signal is set (step S33), and the past camera shake signal is read (step S3).
4). In the second embodiment, one kind of synthesized camera shake velocity signal (v) is obtained.

Next, a prediction operation is performed from the read synthesized camera shake velocity signal and the prediction coefficient to obtain a predicted camera shake signal (step S35). Next, it is determined whether or not the predicted camera shake signal is in the increasing direction (step S36). If the determination is in the increasing direction (YES), the strict allowable limit value Th _u is substituted for the allowable limit value Th for determining the presence or absence of a shake (step S37). However, when the direction is not the increasing direction (NO), the normal allowable limit value th _d is substituted (step S38).

Next, the product of the allowable limit value Th and the predicted camera shake signal exposure time (S) is compared to determine the presence or absence of a shake (step S39). If it is determined in this determination that there is a shake, the process returns to step S24 described above, where the camera shake signal (x, y) is detected, and if it is determined that there is no shake,
The subject image is exposed on the film using the exposure unit 18 (Step S40), and thereafter, the process returns to Step S21.

As described above, according to the camera with reduced camera shake of the second embodiment, the judgment level for the presence or absence of camera shake is set in accordance with the direction in which the camera shake increases or decreases. The determination of "no blur" is prevented.

Immediately after the release switch is depressed, the allowable value is determined strictly even if the camera shake tends to increase, thereby increasing the possibility of permitting the shutter opening (exposure). In addition, the camera shake reduction camera can accurately estimate a camera shake that will occur later with a simpler configuration and can reduce image deterioration due to camera shake at a small size and at low cost.

Further, in this embodiment, the predicted camera shake signal based on the detected camera shake signal is compared with a predetermined camera shake limit value, but the detected camera shake signal itself is compared with the camera shake limit value. Is also good.

In each of the embodiments of the present invention, the method of controlling the timing of starting exposure is used as the shake reducing unit.
The present invention is not limited to this method alone, and can also be applied to a shake reduction method such as changing the exposure time and strobe conditions, and various other modifications can be made without departing from the gist of the invention. Of course, it is possible to apply. Also, an example in which a quadratic expression is used as the prediction calculation has been described, but it is easy to develop a higher-order expression than a cubic expression.

[0090]

As described above in detail, according to the present invention, it is possible to provide a camera having a reduced release time lag and a prevented image blurring without losing the timing of permitting the start of exposure. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a camera shake reduction camera according to the present invention.

FIG. 2 is a diagram showing a configuration of a camera shake reduction camera as a first embodiment according to the present invention.

FIG. 3 is a diagram illustrating a relationship between a time and a transition of a camera shake signal in the camera shake reduction camera according to the first embodiment.

FIG. 4 is a diagram illustrating gain characteristics of prediction characteristics in the camera shake reduction camera of the first embodiment.

FIG. 5 is a diagram illustrating a characteristic of an input frequency with respect to a prediction time among prediction characteristics in the camera shake reduction camera according to the first embodiment.

FIG. 6 is a flowchart for explaining the operation of each component of the first embodiment.

FIG. 7 shows Z and | in the camera shake reduction camera of the first embodiment.
d _x |, | a diagram showing the relationship | d _y.

FIG. 8 is a diagram illustrating an example of a temporal transition of a shake signal d in the camera shake reduction camera according to the first embodiment.

[9] and the hand shake signal in hand shake reduction camera of the first embodiment, a diagram showing the relationship between tolerable Th _d and the allowable limit value Th _u.

FIG. 10 is a flowchart for explaining the operation of a camera shake reduction camera as a second embodiment according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Camera shake detection part, 2 ... Camera shake increase / decrease determination part, 3 ... Camera shake allowable limit setting part, 4, 17, 23 ... Camera shake presence / absence determination part,
5: Exposure request signal generation unit, 6, 10: Exposure unit, 7: Camera shake signal detection unit, 7a: x-axis camera shake signal detection unit, 7b: y
Axis camera shake signal detection unit, 8: camera shake signal prediction unit, 9: exposure start signal output unit, 11: vertical camera shake detection unit, 12 ...
Left and right hand shake detector, 13... First absolute value calculator, 14
... Second absolute value calculation unit, 15 addition unit, 16 camera shake signal processing unit, 18 camera shake reduction unit, 19 first camera shake detection unit, 20 second camera shake detection unit, 21 camera shake synthesis unit, 2
2. Hand shake prediction calculation unit.

Continuation of the front page (72) Inventor Toshiro Kikuchi 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-Limpus Optical Industrial Co., Ltd. Examiner Masahiro Etsuka (56) References JP-A-2-116835 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03B 5/00, 7/097, 17/00

Claims (1)

(57) [Claims] A camera shake detecting means for detecting a camera shake signal related to the camera shake; an exposure request signal generating means for detecting an instruction to start exposure by a manual operation of a photographer and outputting an exposure request signal; When the camera shake is detected,
At the center of exposure based on the shake signal output
Prediction means for predicting a camera shake amount at a point; a camera shake signal predicted by the prediction means;
Limit value of camera shake set to 1/2 of allowable camera shake
Means for determining whether the predicted amount of camera shake is within the above-mentioned range.
An exposure means for performing exposure when it is determined that the value is equal to or less than a threshold value, a camera shake reduction camera having: a camera shake increase / decrease determination means for determining an increase / decrease direction of the camera shake signal output from the camera shake determination means; If the shake signal determined by the increase / decrease determination means is in the increasing direction, the limit value is decreased, and if the shake signal is in the decreasing direction, the limit value is changed to increase the limit value. Camera that reduces camera shake.