JPH1184453A - Camera with shake correcting function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize such a photographing action that a shake correction interrupted during exposure can be started again and the image blurring of an object is suppressed even when an exposure time finishes without re-starting the interrupted shake correction during the interruption. SOLUTION: This camera is provided with an impossible time measurement part measuring the duration of an impossible cause when a proper shake correction becomes impossible and a shutter opening and closing control part controlling a shutter to be closed at the point of time when a proper exposure time tss1 finishes in the case that any duration is zero or under a prescribed time (tg) until the exposure time tss1 finishes from the point of time when the shutter is controlled to be opened and controlling the shutter to be closed at the point of time when the prescribed time (tg) elapses in the case that at least one duration becomes equal to or over the prescribed time (tg) and a limiting exposure time tss2 elapses from the point of time when the shutter is controlled to be opened and controlling the shutter to be closed by waiting for until the limiting exposure time tss2 elapses in the case that it does not elapse.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera that performs exposure while correcting shake of a camera body with respect to a subject.

[0002]

2. Description of the Related Art In recent years, using an area sensor or the like in which a plurality of photoelectric conversion elements such as a plurality of CCDs (charge-coupled devices) are two-dimensionally arranged, the amount of shake of a subject image, particularly caused by camera shake, is detected. A camera having a function of correcting so as to cancel the amount has been proposed. Further, among video cameras, electronic still cameras, and the like, those having similar functions are commercially available.

In such a camera, the above-described shake correction is performed during the exposure time, so that a good photographed image in which image shake is corrected can be obtained. However, shake correction is
It is not always feasible over the entire exposure time. For example, when it is difficult to accurately detect the amount of shake on the way, such as when the contrast of a reference image for shake detection obtained from the area sensor is reduced, shake correction cannot be continued.

[0004] In addition, as shown in FIG. 14, there is a case where it is difficult to correct the shake in the positional relationship between the shake detection area and the image. For example, if the camera shake is large,
During the exposure, the reference image S largely moves within the shake detection area, and if the reference image S deviates from the detection area, shake correction cannot be continued. In particular, from the viewpoint of securing the moving amount of the reference image S, that is, the speed of the image matching process performed to obtain the shake amount, the shake detection area is set in a part of the shooting screen. Is, as shown in FIG.
If it is near the end of the shake detection area, it is likely to be out of the shake detection area due to camera shake (FIG. 14B).
reference).

Further, in an apparatus for performing a shake correction by displacing a shake correction lens, even if a shake amount exceeding a movable range of the shake correction is detected, the shake correction cannot be performed.

In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. 3-170919 discloses a device that emits a flash when the contrast of an image becomes low during exposure. Japanese Patent Application Laid-Open No. Hei 6-308588 discloses that when the shake amount is large and the brightness of the subject is low,
A system is disclosed in which a shutter speed at which underexposure is performed before exposure is determined, and shooting is performed at this shutter speed. Further, Japanese Patent Application Laid-Open No. 7-261230 discloses a method in which, when a shake amount outside the movable range of the shake correction lens is calculated, the shake correction operation is interrupted, and when the shake returns to within the movable range, the shake correction operation is restarted. It has been disclosed.

[0007]

However, according to the method described in Japanese Patent Application Laid-Open No. 3-170919, FIG.
As shown in (2), when the reference image S has deviated from the shake detection area, even if the flash is fired, the shake cannot be detected. In addition, the effect cannot be obtained for a subject to which the flash light does not reach.

In the method described in Japanese Patent Application Laid-Open No. 6-308588, a predetermined state is determined before exposure instead of determining whether or not shake correction is performed during exposure. Once the speed is determined,
Thereafter, the photographing is not performed with the proper exposure time.

Further, in the method described in Japanese Patent Application Laid-Open No. Hei 7-261230, even if the shake correction operation during the interruption is not restarted, the image is exposed for the exposure time determined by the photometry before the exposure. It will not be suppressed.

[0010] The present invention has been made in view of the above circumstances, and by controlling the exposure in accordance with the shake correction disabled time,
It is an object of the present invention to provide a camera with a shake correction function capable of taking an image with the subject image shake suppressed.

[0011]

According to the present invention, there is provided a camera for performing exposure while correcting a shake of a camera body with respect to a subject, and determines whether or not the shake correction is possible during an exposure operation. Determining means, measuring means for measuring a duration during which the shake correction is not possible, and exposure control means for comparing the duration with a predetermined time and controlling exposure according to the comparison result. is there.

In this configuration, for example, the predetermined time is set to such a time that the image blur is hardly noticeable even if the subject image blur occurs over the entire time. If the exposure operation is terminated, if the shake correction can be performed again within the predetermined time, the duration does not exceed the predetermined time, and the shake correction is restarted. Also, if the duration time exceeds a predetermined time, the exposure operation ends even if the elapsed time from the shutter opening time is not the optimal exposure time, so that a photographed image with less noticeable image shake can be obtained. Become.

The shake correction may be restarted if the shake correction is enabled within the predetermined time, and the exposure operation may be terminated if the continuous time exceeds the predetermined time. According to this configuration, if the shake correction can be performed again within the predetermined time, the shake correction is restarted. If the continuous time exceeds the predetermined time, the elapsed time from the shutter opening time is the optimal exposure time. , The exposure operation ends.

[0014] The predetermined time may be equal to or less than half the proper exposure time. According to this configuration, even if the subject image shake occurs over the entire predetermined time, the image shake becomes less noticeable.

Further, the apparatus further comprises a shake detecting means for picking up an image of the subject and detecting the shake from the obtained image, wherein the determining means includes a contrast determining means for determining whether the contrast of the obtained image is low. And when the contrast is determined to be low, the shake correction may be determined to be impossible. According to this configuration, when it is determined that the contrast is low, it is determined that the shake correction is not possible.

[0016]

FIG. 1 is a block diagram of an embodiment of the present invention. The camera 1 includes a photographing unit 2, a correction lens unit 3, a shake detection unit 4, a shake correction amount setting unit 5, a drive unit 6, a position detection unit 7, and an exposure control unit 8.

The photographing unit 2 includes a photographing lens 2 having an optical axis L.
1. An unillustrated mechanism for feeding the loaded film 22 to an image forming position on the optical axis L, and a shutter 23 disposed in front of the film 22 for photographing a subject image.

The correction lens unit 3 includes a horizontal shake correction lens 31 and a vertical shake correction lens 32 disposed in front of the photographing lens 21, and corrects a subject image shake by a prism method. The horizontal shake correction lens 31 and the vertical shake correction lens 32 each have an optical axis parallel to the optical axis L,
It is supported movably in the horizontal and vertical directions orthogonal to each other on a plane orthogonal to the optical axis L.

The shake detecting section 4 includes a detecting lens 41, a shake sensor 42, a shake sensor control section 43, and a signal processing section 44.
And obtains image data for detecting a subject image shake caused by a relative shake of the camera 1 main body with respect to the subject. The detection lens 41 is
It has an optical axis parallel to the optical axis L of the taking lens 21, and forms an object image on the shake sensor 42 behind. The shake sensor 42 is an area sensor in which a plurality of photoelectric conversion elements such as CCDs are two-dimensionally arranged.
1 receives the object image formed in step 1 and obtains an electric signal corresponding to the amount of received light. The image signal of the subject image is obtained as a planar set of pixel signals, which are electric signals obtained by being received by the respective photoelectric conversion elements. The shake sensor control unit 43 causes the shake sensor 42 to repeatedly perform a light receiving operation for a predetermined charge accumulation time (integration time), and to transmit each pixel signal obtained by the light receiving operation to the signal processing unit 44. . The signal processing section 44 performs predetermined signal processing (processing such as signal amplification and offset adjustment) on each pixel signal from the shake sensor 42 and A / D converts the pixel signal into pixel data.

FIG. 2 is a diagram showing an example of a shake detection area covered by the shake detection section 4. As shown in FIG. In the present embodiment, the shake detection unit 4 is configured to cover a shake detection area A1 located at the center and a shake detection area A2 located on the left side as a peripheral area, for example, with respect to the shooting screen. . That is, the shake sensor 42 detects the shake detection area A1 in the subject image formed by the detection lens 41.
And a separate light receiving surface on which a light receiving element is formed only to cover the corresponding subject image in the shake detection area A2. ing.

Note that the shake detecting section 4 may use a shake sensor 42 that covers the entire photographed screen. in this case,
At the stage of image processing, signals of an area corresponding to the detection areas A1 and A2 may be extracted.

The shake correction amount setting unit 5 shown in FIG. 1 includes a shake amount detection unit 51, a coefficient conversion unit 52, and a target position setting unit 5.
3. Correction gain setting unit 54, temperature sensor 55, memory 5
6. Position data input unit 57 and shake correction availability determination unit 58
And sets setting data for generating a drive signal to the drive unit 6. The temperature sensor 55 detects the environmental temperature of the camera 1. The memory 56 is configured by a RAM that temporarily stores image data and data such as the amount of shake used by the shake amount detection unit 51 and a ROM that stores conversion coefficients and the like used by the coefficient conversion unit 52.

FIG. 3 is a block diagram of the shake amount detector 51 and the like. The shake amount detection unit 51 includes a shake amount calculation unit 511, a data selection unit 512, and a predicted shake amount calculation unit 513, calculates a shake amount using image data from the signal processing unit 44, and uses the shake amount. To obtain the predicted shake amount.

The shake amount calculating section 511 includes an image data dump section 511a, a detection area selecting section 511b, and an image comparing / calculating section 511c. The image data dump unit 511a dumps the image data from the signal processing unit 44 to the memory 56 (RAM). Memory 56
Stores image data of each of the shake detection areas A1 and A2.

The detection area selector 511b selects one of the shake detection areas A1 and A2 according to a predetermined selection criterion. As for the selection of the shake detection area, for example, the contrast values of the images in both areas may be compared, and the area having the higher contrast value may be selected.

The detection area selection section 511b sends the image data in the selected shake detection area to the shake correction availability determination section 58.

The image comparison / calculation unit 511c calculates the amount of shake using image data in the shake detection area selected by the detection area selection unit 511b. That is,
For the latest image data stored in the memory 56, an image corresponding to the reference image is extracted as a reference image,
From the amount of change in the reference image position with respect to the reference image position, the shake amount in pixel units is obtained. The shake amount is obtained for each of the horizontal and vertical directions, and is temporarily stored in the memory 56.

The image comparison / calculation section 511c calculates the result of the calculation of the amount of shake (image comparison calculation) by the shake correction determination section 58.
To send to.

FIG. 4 is a perspective view of the vertical shake correction lens 32 and the like housed in the lens barrel. In the present embodiment, the vertical shake correction lens 32 is housed in the lens barrel 24 and is attached to a frame 321 supported rotatably at a fulcrum O. A gear portion 322 is formed on the outer peripheral portion of the frame 321 on the side opposite to the fulcrum O. This gear portion 322
When the motor 632 having the gear 631 meshing with the lens is driven, the vertical shake correction lens 32 moves substantially in the vertical direction.
As understood from FIG. 4, the vertical shake correction lens 32
Within the movable range R corresponding to the inner diameter of the lens barrel 24, it can be moved substantially vertically. The same applies to the horizontal direction.

Here, the image comparison / calculation unit 511 shown in FIG.
The reference image used by c will be described. The reference image is a center position where each lens of the correction lens unit 3 can be moved at a predetermined reference position, for example, each lens can be moved in the opposite direction by the same distance (FIG. 4).
(Where Ra = Rb), the image included in the image data taken in from the shake detecting unit 4. In this way, by using the center position as a reference, the problem that the lens that is likely to occur when one movable range is shorter than the other can easily hit the end can be avoided.

FIG. 5 is an explanatory diagram of shake amount data selection and extraction by the data selection unit 512. Data selection unit 512
Is to selectively extract four shake amounts including the latest shake amount from the memory 56 using a predetermined reference time (speed calculation time Tv and acceleration calculation time Tα). That is, the shake amount Ea at the latest time point t1 (hereinafter referred to as ta) is selectively extracted, and is longer and shorter than Tv (the time width required for obtaining a shake speed having required reliability) at the time point ta. A time point t3 (hereinafter, referred to as tb) is retrieved, and the shake amount Eb at the time point tb is selectively extracted. Further, a time point t5 (hereinafter referred to as tc) which is longer and shorter than Tα (the time width required for obtaining the shake acceleration having the required reliability) is searched for the time point ta, and at this time point Tc The shake amount Ec is selectively extracted. Further, a time point t7 (hereinafter referred to as td) which is longer and shorter than the above-described Tv with respect to the time point tc is searched,
The shake amount Ed at this time point td is selectively extracted. These four shake amounts Ea, Eb, Ec, Ed and time point t
a, tb, tc, and td are selectively extracted in each of the horizontal and vertical directions, and stored in the memory 56 correspondingly.

However, the time is older in the order of the time points t1, t2,... Each time point represents an intermediate time point of the integration time. Further, upward arrows at each time point indicate detected shake amounts, and these shake amounts are stored in the memory 56.

The data selection section 512 is not limited to the above selection method, and may select the amount of shake at the time when the separation time is closest to the predetermined reference time, or may be shorter than the predetermined reference time and the longest. The amount of shake at the point in time when the separation time becomes may be selected.

The predicted shake amount calculator 513 shown in FIG.
Is a data selection unit 512 for each of the horizontal and vertical directions.
Is used to calculate the predicted shake amount using the four shake amounts selected and extracted in (1). That is, the latest shake amount Ea and the past shake amount Ea
The shake speed V1 is obtained from the two shake amounts Eb by (Equation 1), and the shake speed V2 is obtained from (Rev. 2) from the remaining two old shake amounts Ec and Ed. Then, the shake acceleration α is obtained from the shake speeds V1 and V2 by (Equation 3).

[0035]

V1 = (Ea−Eb) / (ta−tb)

[0036]

V2 = (Ec−Ed) / (tc−td)

[0037]

Α = (V1−V2) / (ta−tc) Next, based on the assumption that the shake due to the hand shake changes substantially according to the uniform acceleration motion, the latest shake amount Ea,
From the shake speed V1 and vibration acceleration alpha, prediction shake amount E _P is calculated by the equation (4).

[0038]

(Equation 4)

Here, the constant k (0 <k <1) is a correction coefficient for approaching the actual camera shake, and T _p =
(1/2) × T1 + T2 + T3 + T4 + Td. Here, the time T1 is the integration time of the shake sensor 42, and the time T2
Is the transfer time required for the image information of the shake sensor 42 to be dumped in the memory 56, time T3 is the calculation time for calculating the shake amount, and time T4 is the calculation time for calculating the predicted shake amount. The time Td is a time required from when the shake amount detection unit 51 sends out the estimated shake amount to when the driving by the correction lens unit 3 is completed.

The coefficient conversion unit 52 shown in FIG. 1 calculates the horizontal and vertical predicted shake amounts by using the conversion coefficients stored in the memory 56 and the horizontal and vertical target angular positions with respect to the correction lens unit 3. (Drive amount). Further, the coefficient conversion unit 52 calculates a correction coefficient according to the environmental temperature detected by the temperature sensor 55, and corrects the horizontal and vertical target angle positions using the correction coefficient. This correction factor is
This is for correcting a change in the focal length of the detection lens 41 and a change in the refractive index (power) of light caused by the correction lens unit 3 due to a change in environmental temperature.

The target position setting section 53 converts the target angle position in the horizontal and vertical directions after temperature correction into target position information (drive end position). These horizontal and vertical target position information are set in the drive unit 6 as setting data SD _PH and SD _PV , respectively.

When the target position setting section 53 receives a reset command from the shake correction determination section 58, the target position information in the horizontal and vertical directions obtained by the conversion when the command is not received is received. The setting data SD _PH and SD _PV are reset in the drive unit 6 respectively.

The correction gain setting section 54 includes a temperature sensor 55
The gain correction amounts in the horizontal and vertical directions are obtained according to the environmental temperature detected in step (1), and these are set in the drive unit 6 as setting data SD _GH and SD _GV . The horizontal and vertical gain correction amounts correct the horizontal and vertical basic gains, respectively. Details of the setting data SD _GH and SD _GV and the basic gain will be described later.

The position data input unit 57 A / D converts each output signal of the position detection unit 7 and monitors each position of the horizontal shake correction lens 31 and the vertical shake correction lens 32 from the obtained output data. Things. By monitoring this position data, it is possible to detect an abnormal state of the drive mechanism for the correction lens unit 3 and the like.

FIG. 6 is a block diagram of the shake correction availability determination section 58. The shake correction availability determination unit 58 includes a low contrast (low contrast) determination unit 581, an area over determination unit 582, an end arrival determination unit 583, and an availability determination unit 584, and determines whether or not appropriate shake correction is possible.

The low contrast determination unit 581 compares the contrast value of the image data from the detection area selection unit 511b with a predetermined value (threshold), and determines whether the image in the selected shake detection area is low contrast. It is determined whether or not. That is, if the contrast value of the image data is equal to or less than a predetermined value, it is determined that the image is a low contrast, and a low contrast state that causes an inappropriate shake correction is detected.

The area over determining section 582 determines whether or not the area is over based on the image comparison calculation result from the image comparison calculating section 511c. In the present embodiment, if the image comparison / calculation unit 511c cannot detect the reference image corresponding to the reference image from the shake detection area selected by the detection area selection unit 511b, it is determined that the area is over and appropriate shake correction is performed. An area over condition which causes an impossibility is detected. The result of the image comparison operation is not limited to the detection result of the detection of the reference image, but may be the shake amount itself because it is possible to determine whether or not the area is over by checking the shake amount.

The end-of-arrival determination unit 583 determines that at least one of the horizontal shake correction lens 31 and the vertical shake correction lens 32 has reached the movement end position from each position information from the position data input unit 57 (hereinafter simply referred to as the end position). Is reached.). That is, if at least one has reached the movement end position, it is determined that the end has been reached, and the end arrival state that causes an improper shake correction is detected.

The availability determining unit 584 includes a low contrast determining unit 58
1. Area over determination unit 582 and terminal arrival determination unit 5
In accordance with the determination result of 83, it is determined whether or not appropriate shake correction is possible. In the present embodiment, if a determination result indicating at least one of the low contrast, the area over, and the arrival at the end is obtained, it is determined that appropriate shake correction is not possible.

If appropriate shake correction is not possible, the possibility determination section 584 issues a reset command to the target position setting section 53.
Notify. By the notification of the reset command, the execution of the shake correction is interrupted, and each lens of the correction lens unit 3 is driven to stop at the current position (see FIG. 11B).

The drive section 6 comprises a drive control circuit 61, a horizontal actuator 62 and a vertical actuator 63. The drive control circuit 61 includes setting data SD _PH and S _PH from the target position setting unit 53 and the correction gain setting unit 54.
It generates horizontal and vertical drive signals in accordance with D _PV , SD _GH , and SD _GV . The horizontal actuator 62 and the vertical actuator 63 are composed of a coreless motor or the like (see the motor 632 and the gear 631 in FIG. 4), and perform horizontal shake correction in accordance with horizontal and vertical drive signals generated by the drive control circuit 61, respectively. Lens 31 and vertical shake correction lens 3
2 is driven.

FIG. 7 is a block diagram showing an example of the drive control circuit 61 constituting a part of the servo circuit. First, the setting data SD _GH , SD set in the drive control circuit 61
_GV will be described. When the environmental temperature of the camera 1 changes, various characteristics of the drive system for shake correction change. For example, as the environmental temperature changes, each torque constant of the motor (see the motor 632 in FIG. 4), the backlash of the drive system (movable mechanism) in the correction lens unit 3 and the drive unit 6, and the gear ( The hardness of the gear portion 322 and the gear 631 in FIG. 4) changes.

FIG. 8 is a temperature characteristic diagram of the motor torque which is a factor of this change. As can be understood from FIG.
If the environmental temperature deviates from the reference temperature (for example, 25 ° C.), the motor torque indicates a value different from the value at the reference temperature. As a result, the drive characteristics related to the shake correction change. As described above, the drive characteristics based on the horizontal and vertical basic gains (drive gains at the reference temperature) change when the environmental temperature obtained by the temperature sensor 55 deviates from the reference temperature.

Therefore, the correction gain setting section 54 generates a gain correction amount for correcting a change in drive characteristics due to each of the basic gains in the horizontal and vertical directions according to the environmental temperature obtained by the temperature sensor 55. In the present embodiment, a function (environment temperature is used as an argument) for obtaining a gain correction amount for individually correcting each variation such as motor torque, backlash, and gear hardness that occurs when the environment temperature deviates from the reference temperature. )But,
It is determined in advance for each of the horizontal and vertical directions. Then, for each of the horizontal and vertical directions, the environmental temperature detected by the temperature sensor 55 is input to each correction function, and the total value of the obtained values is obtained as a gain correction amount. These gain correction amounts in the horizontal and vertical directions are respectively set in the setting data SD.
_GH and SD _GV are set in the drive control circuit 61.

Next, the drive control circuit 61 will be described. In FIG. 1, the setting data SD _GH , SD
_{The GV} is illustrated as being transmitted on two signal lines, but actually, two data lines (SCK, SD) not shown
And serially transmitted and set by three control lines (CS, DA / GAIN, X / Y). Similarly, the setting data D _PH and SD _PV are sent to the drive control circuit 61 alternately.

For this purpose, the drive control circuit 61 includes a buffer, a sample hold circuit, and the like. That is, FIG.
, The buffers 601 and 602 store setting data S that are set alternately from the target position setting unit 53, respectively.
This is a memory for storing D _PH and SD _PV .

The DAC 603 is a D / A converter, and converts the setting data SD _PH set in the buffer 601 into a target position voltage V _PH . Further, the DAC 603 converts the setting data SD _PV set in the buffer 602 into a target position voltage V _PV .

S / Hs 604 and 605 are sample and hold circuits. The S / H 604 samples the target position voltage V _PH converted by the DAC 603, and holds the value until the next sampling. Similarly, S / H605
Samples the target position voltage V _PV converted by the DAC 603 and holds the value until the next sampling.

The adder circuit 606 calculates the difference voltage between the target position voltage V _PH and the output voltage V _H of the lateral position detector 71. The addition circuit 607 obtains a difference voltage between the target position voltage V _PV and the output voltage V _V of the vertical position detection unit 72. The adder circuits 606 and 607 add the negative output voltages V _H and V _V output from the horizontal position detector 71 and the vertical position detector 72 to the target position voltages V _PH and V _PV , respectively, to obtain a difference voltage. Seeking.

V / V 608 amplifies the input voltage to a voltage as a lateral proportional gain at a preset ratio with respect to the reference temperature, and V / V 609 converts the input voltage to the reference temperature. To a voltage set as a proportional gain in the vertical direction at a preset ratio. Here, the proportional gain in the lateral direction refers to the lateral shake correction lens 31.
Is a gain proportional to the difference between the target position of the horizontal shake correction lens 31 and the position of the lateral shake correction lens 31 detected by the horizontal position detection unit 71. The vertical proportional gain is a gain proportional to the difference between the target position of the vertical shake correction lens 32 and the position of the vertical shake correction lens 32 detected by the vertical position detection unit 72.

The differentiating circuit 610 performs differentiation by a predetermined time constant with respect to the reference temperature on the difference voltage obtained by the adding circuit 606 to obtain a voltage as a differential gain in the horizontal direction. The obtained voltage corresponds to a speed difference in the lateral direction (difference between the target drive speed and the current drive speed). Similarly, the differentiating circuit 611 obtains a voltage as a differential gain in the vertical direction by performing differentiation by a preset time constant with respect to the reference temperature on the difference voltage obtained by the adding circuit 607. The obtained voltage corresponds to a vertical speed difference (difference between the target driving speed and the current driving speed).

In this way, the V / V 608 and 609 and the differentiating circuits 610 and 611 set the proportional and differential gains as the basic gain with respect to the reference temperature in each of the horizontal and vertical directions.

The buffer 612 includes the correction gain setting section 54
It is a memory for storing the setting data _SDGH from. The setting data _SDGH is a gain correction amount (proportional and differential gain correction amount) for correcting the horizontal basic gain (proportional and differential gain). The buffer 613 is a memory that stores the setting data SD _GV from the correction gain setting unit 54. The setting data SD _GV is a gain correction amount (proportional and differential gain correction amount) for correcting the vertical basic gain (proportional and differential gain).

The HP gain correction circuit 614 has a V / V60
8 with respect to the horizontal proportional gain obtained in
An analog voltage corresponding to the horizontal proportional gain correction amount from 12 is added to output a horizontal proportional gain after temperature correction. The VP gain correction circuit 6
Numeral 15 adds an analog voltage corresponding to the vertical proportional gain correction amount from the buffer 613 to the vertical proportional gain obtained by the V / V 609, and outputs a vertical proportional gain after temperature correction. Is what you do.

The HD gain correction circuit 616
An analog voltage corresponding to the horizontal differential gain correction amount from the buffer 612 is added to the horizontal differential gain obtained in step 10 to output the horizontal differential gain after temperature correction. Further, the VD gain correction circuit 617 adds an analog voltage corresponding to the vertical differential gain correction amount from the buffer 613 to the vertical differential gain obtained by the differentiating circuit 611, and outputs the vertical differential gain after temperature correction. It outputs the differential gain in the direction.

As described above, the HP gain correction circuit 614,
VP gain correction circuit 615, HD gain correction circuit 616
And the VD gain correction circuit 617 performs temperature correction on the proportional and differential gains as the basic gain.

The LPF 618 includes an HP gain correction circuit 61
4 and a low-pass filter for removing high-frequency noise included in each output voltage of the HD gain correction circuit 616. L
The PF 619 is a low-pass filter that removes high-frequency noise included in each output voltage of the VP gain correction circuit 615 and the VD gain correction circuit 617.

The driver 620 includes LPFs 618 and 61
9 is a motor driving IC that supplies drive power corresponding to the output voltage of No. 9 to the horizontal actuator 62 and the vertical actuator 63, respectively.

The position detector 7 shown in FIG. 1 comprises a horizontal position detector 71 and a vertical position detector 72.
The horizontal position detector 71 and the vertical position detector 72 detect the current positions of the horizontal shake correction lens 31 and the vertical shake correction lens 32, respectively.

FIG. 9 is a block diagram of the horizontal position detecting section 71. The horizontal position detection unit 71 includes a light emitting diode (LED) 7.
11, a slit 712 and a PSD 713.
The LED 711 is connected to the frame 31 of the horizontal shake correction lens 31.
1 (see LED 721 in FIG. 4). The slit 712 is an LED
This is for sharpening the directivity of light emitted from the light emitting unit 711. The PSD 713 is attached to a position facing the LED 711 on the inner wall side of the lens barrel 24,
It outputs photoelectric conversion currents I1 and I2 having values corresponding to the light receiving position (centroid position) of the luminous flux emitted from the ED 711. By measuring the difference between the photoelectric conversion currents I1 and I2,
The position of the lateral shake correction lens 31 is detected. The vertical position detection section 72 is also configured to detect the position of the vertical shake correction lens 32 in the same manner.

FIG. 10 is a block diagram of the horizontal position detecting section 71. The horizontal position detection unit 71 includes the LED 711 and the PSD
In addition to the components 713, I / V conversion circuits 714 and 715, an addition circuit 716, a current control circuit 717, a subtraction circuit 718, an LPF 719, and the like. The I / V conversion circuits 714 and 715 respectively output the output current I
1, I2 are converted into voltages V1, V2. The addition circuit 716 obtains an addition voltage V3 of the output voltages V1 and V2 of the I / V conversion circuits 714 and 715. The current control circuit 717 increases or decreases the base current of the transistor Tr1 so as to keep the output voltage V3 of the adder circuit 716, that is, the light emission amount of the LED 711 constant. The subtraction circuit 718 calculates a difference voltage V4 between the output voltages V1 and V2 of the I / V conversion circuits 714 and 715. LPF
Reference numeral 719 cuts a high-frequency component included in the output voltage V4 of the subtraction circuit 718.

Next, the detection operation by the horizontal position detector 71 will be described. Current I sent from PSD 713
1 and I2 are converted into voltages V1 and V2 by I / V conversion circuits 714 and 715, respectively.

Next, the voltages V1 and V2 are added to the adder 716.
Is added. The current control circuit 717 supplies a current at which the voltage V3 obtained by the addition is always constant to the base of the transistor Tr1. The LED 711 emits light with a light amount corresponding to the base current.

On the other hand, the voltages V1 and V2 are subtracted from the subtraction circuit 718.
Is subtracted. The voltage V4 obtained by this subtraction is a value indicating the position of the lateral shake correction lens 31. For example, when there is a light receiving position (center of gravity position) at a position that is distance x to the right from the center of PSD 713, length x, current I1,
The light receiving area length L of I2 and PSD 713 satisfies the relationship of (Equation 5).

[0075]

(Equation 5)

Similarly, the length x, the voltages V1 and V2, and the light receiving area length L satisfy the relationship of (Equation 6).

[0077]

(Equation 6)

From this, the value of V2 + V1, that is, the voltage V3
Is controlled to be always constant, the relationship of (Equation 7) is obtained, and the value of V2−V1, that is, the value of the voltage V4 becomes the length x
The position of the lateral shake correction lens 31 can be detected by monitoring the voltage V4.

[0079]

(Equation 7)

The exposure control unit 8 shown in FIG.
1, an exposure determining unit 82, an unacceptable time measuring unit 83, and a shutter opening / closing control unit 84. The photometric unit 81
The light from the subject is received by a photoelectric conversion element such as Cds (cadmium sulfide) and the brightness of the subject (subject brightness) is detected.

The exposure determining section 82 includes an appropriate exposure time determining section 821 for determining an appropriate exposure time (tss1) according to the subject brightness, and a limit exposure time determining section 822 for determining a limit exposure time (tss2) from tss1. It is configured. In the present embodiment, the limit exposure time is set to half of tss1 (under one step). The limit exposure time is not limited to this, and may be, for example, two steps under half of tss1 or less. In short, the limit exposure time may be a time within a range in which image deterioration due to underexposure can be corrected at the time of printing.

When the appropriate shake correction becomes impossible, the unacceptable time measuring section 83 measures the duration of the cause of the inability to correct the shake. That is, if the shake correction cannot be performed in the low contrast, the duration (TM1) of the low contrast state is measured. Also,
If the shake correction becomes impossible due to the area over, the continuation time (TM2) of the area over state is measured. Further, if the shake correction becomes impossible at the end point, the duration time (TM3) of the end point state is measured. However, the duration TM1,
TM2 and TM3 are set to “0” by default. Note that the unacceptable time measuring unit 83 calculates the duration times TM1, TM2,
Instead of measuring the TM3 individually, it is also possible to collectively measure the time during which at least one state of low contrast, area over, and arrival at the end is continued.

FIGS. 11A and 11B are views showing the state of control by the shutter opening / closing control section 84. FIG. 11A shows a case where opening / closing control is performed with a proper exposure time, and FIG. The case where control is performed is shown. The shutter opening / closing controller 84 determines the proper exposure time ts from the time of the shutter opening control.
By the end of s1, if any of the durations of TM1, TM2, and TM3 is “0” (see FIG. 11A) or less than a predetermined time tg, the shutter closing control is performed at the end of tss1 (this operation is performed) At this time, the actual exposure time tss is tss1
become). In the present embodiment, even if the shake correction cannot be performed within tss1, if the shake correction can be performed again in a short time shorter than the predetermined time tg (for example, 1/8 of tss2), the influence on the image shake is small. Therefore, the shake correction is restarted.
On the other hand, at least one of the durations TM1, TM2, TM3
If one of them is equal to or longer than the predetermined time tg, the shutter closing control is performed if the limit exposure time tss2 has elapsed from the time of the shutter opening control, as shown in FIG.
Tss from the time of shutter opening control.
If 2 has not elapsed, it is performed after elapse.
Note that the predetermined time tg is not limited to one-eighth of tss2,
For example, half of tss1 may be sufficient.
Even if the subject image shake occurs over the entire time of tg, any time may be used as long as the image shake is not noticeable.

The shake sensor control unit 43, signal processing unit 44, shake amount detection unit 51, coefficient conversion unit 52, target position setting unit 53, correction gain setting unit 54, position data input unit 5
7. The shake correction availability determination unit 58, the exposure determination unit 82, the impossible time measurement unit 83, and the shutter open / close control unit 84 are configured by an MPU (microprocessor unit) that executes a program describing the following processing. Further, each of the above units may be configured by one or a plurality of MPUs.

Next, the exposure processing of the camera 1 will be described. FIG. 12 is a flowchart of a subroutine "exposure process". This subroutine is called when a shutter release button (not shown) is fully pressed. When this subroutine is called, each lens of the correction lens unit 3 is driven to the center position (# 5). Next, shake detection starts (# 10), and the horizontal and vertical shake amounts required to calculate the predicted horizontal and vertical shake amounts are obtained.
Stored in the memory 56. This makes it possible to calculate the predicted shake amounts in the horizontal and vertical directions from the first processing of “shake correction” in step # 20 described below. In calculating the shake amount, one of the shake detection areas A1 and A2 is selected. When the shake amount calculation is completed, the setting data SD _GH and SD _GV are set in the drive unit 6.

Next, the shutter 23 opens according to the shutter opening control (# 15), and a subroutine of "shake correction" described later is executed (# 20). Thereafter, the shutter 23 is closed according to the closing control (# 25), and the process returns.

Each lens of the correction lens unit 3 is driven to the center position in step # 5, but is not limited to this, and is driven to the center position before this subroutine is called. You may do so.

FIG. 13 is a flowchart of a subroutine "vibration correction". When this subroutine is called, horizontal and vertical shake amounts are detected (# 100),
Stored in the memory 56.

Thereafter, it is determined whether or not the area is over (# 105), and then, it is determined whether or not the terminal is reached (# 110).

Next, after it is determined whether or not it is a low contrast, it is determined whether or not shake correction is possible according to the result of the low contrast determination (# 115).

If it is not a low contrast (NO in # 115),
That is, if the shake can be corrected with respect to the contrast, it is determined whether or not the shake can be corrected according to the determination result of the area over in step # 105 (# 120).

If the area is not over (N in # 120)
O), that is, if the shake can be corrected for the area over, it is determined whether or not the shake can be corrected according to the determination result of the arrival at the end in step # 110 (# 125).

If the end is not reached (NO in # 125),
That is, if appropriate shake correction is possible, the predicted shake amount is calculated from the shake amount stored in the memory 56 in each of the horizontal and vertical directions (# 130). Each of the calculated predicted shake amounts is converted to a target angle position, subjected to temperature correction, and then converted to a target position. These horizontal and vertical target position information are set in the drive unit 6 as setting data SD _PH and SD _PV , respectively (# 135). As a result, each lens of the correction lens unit 3 moves so as to suppress the occurrence of subject image shake due to camera shake.

Next, it is determined whether or not the flag Fg is "1"(# 140). If Fg is not "1" (NO in # 140), it is determined whether or not the elapsed time Tc from the shutter opening control is equal to or longer than the proper exposure time tss1 (# 145). If Tc is not equal to or greater than tss1 (NO in # 145), the process returns to step # 100. If Tc is equal to or greater than tss1 (YES in # 145), the process returns.

If Fg is "1" (YE at # 140)
S), it is determined whether or not the elapsed time Tc is equal to or longer than the limit exposure time tss2 (# 150). Tc is tss2
If not (NO in # 150), step # 100
And if Tc is not less than tss2 (YE in # 150)
S), and return.

On the other hand, if it is low contrast (YE in # 115)
S), that is, if appropriate shake correction is not possible with the low contrast,
It is determined whether or not the duration TM1 of the low contrast state is equal to or longer than the predetermined time tg (# 155). TM1 is tg
If this is the case (YES in # 155), the flag Fg is set to "1"(# 160). Thereafter, the process proceeds to step # 140.

If TM1 is not equal to or greater than tg (NO in # 155), the duration TM
1 is updated (# 165). Next, a reset command is notified from the shake correction availability determination unit 58 to the target position setting unit 53, and the latest horizontal and vertical target position information when this instruction is not notified are set data SD _PH and S respectively.
It is set again to the drive unit 6 as D _PV (# 155). As a result, each lens of the correction lens unit 3 stops at the current position. Thereafter, the process proceeds to step # 140.

If the area is over (YE in # 120)
S), that is, if appropriate shake correction is not possible due to area over, it is determined whether or not the duration TM2 of the area over state is equal to or longer than tg (# 175). If TM2 is equal to or greater than tg (YES in # 175), step # 1
Proceed to 60.

If TM2 is not equal to or greater than tg (NO in # 175), the duration TM
2 is updated (# 180). Next, a reset command is notified from the shake correction availability determination unit 58 to the target position setting unit 53, and the latest horizontal and vertical target position information when this instruction is not notified are set data SD _PH and S respectively.
It is set again to the drive unit 6 as D _PV (# 185). As a result, each lens of the correction lens unit 3 stops at the current position. Thereafter, the process proceeds to step # 140.

If the terminal has arrived (YES in # 125),
That is, if appropriate shake correction is not possible at the end point, it is determined whether or not the duration time TM3 of the end point state is equal to or longer than tg (# 190). If TM3 is equal to or greater than tg (YES in # 190), the flow advances to step # 160.

If TM3 is not equal to or greater than tg (NO in # 190), the duration TM
3 is updated (# 195). Next, a reset command is notified from the shake correction availability determination unit 58 to the target position setting unit 53, and the latest horizontal and vertical target position information when this instruction is not notified are set data SD _PH and S respectively.
It is set again to the drive unit 6 as D _PV (# 200). As a result, each lens of the correction lens unit 3 stops at the current position. Thereafter, the process proceeds to step # 140.

In this embodiment, the durations TM1,
TM2 and TM3 are each compared with the same predetermined time tg, but may be compared with corresponding individual times. For example, when appropriate shake correction cannot be performed with the low contrast, it is unlikely that shake correction will be possible again, so that TM1 may be compared with a shorter time than the others.

Since the limit exposure time differs depending on the characteristics of the film used for photographing, it may be changed according to the type of the film used.

Further, in the present embodiment, the shake correction availability determination section 58 determines whether or not appropriate shake correction is possible according to any of low contrast, area over, and arrival at the end. However, the present invention is not limited thereto. Instead, for example, when an abnormal state of the shake correction drive system or an abnormal output of the shake detection system is detected, it may be determined that appropriate shake correction cannot be performed. The abnormal state of the shake correction drive system may be detected when, for example, the shake correction lens unit 3 causes vibration or the like and the control performance deteriorates. In addition, the abnormal output of the shake detection system may be detected when a shake amount that is not considered to be the original shake is calculated.

In FIG. 13, the processes of steps # 105 and # 110 are executed before the determination of steps # 115 to # 125. However, the process of step # 105 is executed immediately before step # 120. And step # 1
The process of 10 may be executed immediately before step # 125. Thus, for example, when it is determined that appropriate shake correction cannot be performed with the low contrast, step 10
5,110 processing can be skipped.

Further, the terminal arrival determining unit 583 determines the terminal arrival from the output of the position data input unit 57, but is not limited thereto, and may detect the terminal arrival by a mechanical switch or the like.

[0107]

As is apparent from the above description, according to the first aspect of the present invention, it is possible to resume the shake correction interrupted during the exposure, and without restarting the shake correction during the interruption. Even when the exposure time has ended, it is possible to take a picture in which the subject image shake is suppressed.

According to the second aspect of the invention, if the shake correction can be performed again within a predetermined time, the shake correction can be restarted.
The exposure operation can be ended even if the elapsed time from the shutter opening time is not the optimal exposure time.

According to the third aspect of the present invention, even if the subject image shake occurs over the entire predetermined time, the image shake can be made inconspicuous.

According to the fourth aspect of the present invention, it is possible to determine whether or not shake correction due to low contrast is impossible.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a shake detection area covered by a shake detection unit.

FIG. 3 is a block diagram of a shake amount detection unit and the like.

FIG. 4 is a perspective view of a vertical shake correction lens and the like housed in a lens barrel.

FIG. 5 is an explanatory diagram of shake amount data selection and extraction by a data selection unit.

FIG. 6 is a block diagram of a shake correction availability determination unit.

FIG. 7 is a block diagram showing an example of a drive control circuit forming a part of a servo circuit.

FIG. 8 is a temperature characteristic diagram of a motor torque which is a factor of a change in drive characteristics.

FIG. 9 is a configuration diagram of a horizontal position detection unit.

FIG. 10 is a block diagram of a horizontal position detection unit.

11A and 11B are diagrams illustrating a state of control of a shutter opening / closing control unit. FIG. 11A illustrates a case where opening / closing control is performed with a proper exposure time, and FIG. 11B illustrates a case where opening / closing control is performed with a time shorter than the proper exposure time. Is shown.

FIG. 12 is a flowchart of a subroutine of “exposure processing”.

FIG. 13 is a flowchart of a subroutine of “shake correction”.

14A is a diagram illustrating a state in which a subject is located in a shake detection area at the start of shake correction, and FIG. 14B is a view illustrating a state in which the subject is out of the shake detection area during shake correction. FIG.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 camera 2 imaging unit 3 correction lens unit 4 shake detection unit (shake detection unit) 5 shake correction amount setting unit 6 drive unit 7 position detection unit 8 exposure control unit (exposure control unit) 21 shooting lens 22 film 23 shutter 31 lateral shake Correction lens 32 Vertical shake correction lens 41 Detection lens 42 Shake sensor 43 Shake sensor control unit 44 Signal processing unit 51 Shake amount detection unit 52 Coefficient conversion unit 53 Target position setting unit 54 Correction gain setting unit 55 Temperature sensor 56 Memory 57 Position data Input unit 58 Shake correction availability determination unit (judgment unit) 61 Drive control circuit 62 Horizontal actuator 63 Vertical actuator 71 Horizontal position detection unit 72 Vertical position detection unit 81 Photometry unit 82 Exposure determination unit 83 Impossible time measurement unit (Measurement unit) 84 Shutter Opening / closing control unit 581 Low contrast judgment unit (judgment means, contrast Constant means) 582 Area over determination section (determination means) 583 termination arrival determination section (determination means) 584 determining section (determining means)

Claims (4)

[Claims] 1. A camera that performs exposure while correcting a shake of a camera body with respect to a subject, and a determination unit that determines whether the shake correction is possible during an exposure operation, and measures a duration during which the shake correction is not possible. A camera with a shake correction function, comprising: a measuring unit that performs the exposure; and an exposure control unit that compares the continuation time with a predetermined time and controls the exposure according to a result of the comparison. 2. The method according to claim 1, wherein the shake correction is restarted if the shake correction is enabled within the predetermined time, and the exposure operation is terminated if the duration exceeds the predetermined time. Item 2. A camera with a shake correction function according to Item 1. 3. The camera with a shake correction function according to claim 1, wherein the predetermined time is not more than half of an appropriate exposure time. 4. A camera according to claim 1, further comprising: a shake detecting unit that captures an image of the subject and detects the shake from an obtained image.
The apparatus according to claim 1, further comprising a contrast determination unit configured to determine whether a contrast of the obtained image is low, and determining that the shake correction is not possible when the contrast is determined to be low. A camera with a shake correction function according to 1.