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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to cameras, and more particularly,
to a camera having a camera-shake detector which detects camera-shake
occurring when a picture is taken.
2. Description of the Related Arts
Some conventional cameras have been proposed with camera-shake detecting
sensors which detect camera-shake to prevent pictures being blurred. A
conventional camera provided with a camera-shake detecting sensor
comprises a camera-shake detecting sensor, a correcting device for
correcting camera-shake amount in response to output of detection, and a
display unit for making display of a warning that a picture is being
blurred.
A conventional camera which can correct camera-shake is responsive to
output of camera-shake detecting sensor for correcting camera-shake amount
so as to allow unblurred pictures to be taken and at the same time,
display that unblurred picture are being taken.
Conventional cameras with camera-shake sensors are configured as described
above. Therefore, the conventional cameras with camera-shake sensors make
correction of camera-shake and at the same time, give a display that
camera-shake is corrected.
However, it takes time for the camera-shake sensors to become able to
provide stable output of camera-shake detection after the sensors are
turned on. Accordingly, the output of the sensors can not be used until
stabilized. Therefore, pictures taken before the sensors are stabilized
can not be subjected to camera-shake correction. As a result, even those
cameras provided with camera-shake-sensors and correction mechanism may
produce blurred pictures without operating such mechanism in such a case.
SUMMARY OF THE INVENTION
An object of the present invention is to take reliably unblurred pictures
using a camera with a camera-shake sensor.
Another object of the present invention is to eliminate unnecessary
continuous driving of a taking lens in a camera with a camera-shake
sensor.
Still another object of the present invention is to more precisely correct
camera-shake in a camera with a camera-shake sensor.
According to the present invention, the objects described above can be
achieved by a camera comprising the following elements. That is, a camera
according to the present invention comprises a camera-shake detector for
detecting camera-shake occurring when a picture is taken, a correction
device for correcting camera-shake in response to output of the
camera-shake detector, and a warning display unit for displaying a warning
when the camera-shake detector is not operating.
Camera-shake detecting means can not detect camera-shake amount immediately
after a signal for starting its operation is entered. Therefore, when such
a camera-shake detector is in an inoperable state, a warning that the
camera can not make camera-shake correction is displayed at a warning
display portion. Then, a photographer can recognize that the camera-shake
correction device is not operating and thus, does not start photographing
until output of the camera-shake sensor is stabilized. As a result, it
becomes possible to take reliably unblurred pictures using the camera with
a camera-shake sensor.
In a camera according to the present invention, lens driving for
camera-shake correction is detected when the camera-shake amount is large
in the out-of-focus state. When the camera-shake amount is large in the
out-of-focus state, the in-focus state can not be easily realized even if
a taking lens is driven. According to the present invention, driving of a
taking lens is inhibited when the camera-shake amount is large in the
out-of-focus state. Therefore, unnecessary driving of the taking lens is
eliminated in the camera with a camera-shake sensor.
According to the present invention, the camera-shake amount of a moving
object is estimated using a plurality of camera-shake data. Accordingly, a
precise camera-shake correction can be made in a camera with a
camera-shake sensor even when an object is in motion.
The foregoing and other objects, features, aspects and advantages of the
present invention will become more apparent from the following detailed
description of the present invention when taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic perspective view of a camera system according to the
present invention.
FIG. 2 is a circuit block diagram of a camera body according to the present
invention.
FIGS. 3 to 7 are flow chart diagrams showing operation of the camera system
according to the present invention.
FIGS. 8A and 8B are diagrams showing performance of a camera-shake sensor
according to the present invention.
FIGS. 9A to 13C are flow chart diagrams for explaining operation of a
camera according to the present invention.
FIGS. 14A and 14B are diagrams showing an AE program.
FIG. 15 is a flow chart diagram for explaining operation of a camera
according to the present invention.
FIGS. 16A and 16B are diagrams showing contents displayed at the display
portion and in the finder of a camera body.
FIGS. 17A and 17B are flow charts for explaining operation of a camera
system according to the present invention.
FIGS. 18 to 23 are circuit block diagrams of a camera-shake detector
applicable to the present invention and flow chart diagrams of a
microcomputer controlling the circuit.
FIG. 24 is a circuit diagram showing a the electronic flash device ST
circuit.
FIG. 25 is a circuit diagram showing circuit structure of lens.
FIGS. 26 and 27 are flow charts diagrams for explaining operation of a
microcomputer on the side of lens.
FIG. 28 is a diagram showing results of a simulated correction of
camera-shake.
FIGS. 29 and 30 are diagrams showing driving mechanism of a correction lens
which performs correction of camera-shake according to the present
invention.
FIG. 31 is a flow chart diagram for explaining operation of the driving
mechanism.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the following, embodiments of the present invention will be described
with reference to the accompanying drawings. Meanwhile, the description
below is made not only on system of the present invention but on the
entire system including those parts or functions that have no direct
relation with the present invention.
FIG. 1 is a schematical perspective view of a camera having a camera-shake
detecting sensor according to the present invention. Referring to FIG. 1,
the camera according to the present invention comprises camera body 1 and
lens 2 interchangeably provided to camera body 1. Camera body 1 comprises
X direction camera-shake sensor Sx for detecting camera-shake amount in
the X direction in the figure, Y direction camera-shake sensor Sy for
detecting camera-shake amount in the Y direction, and display portion
DISP.sub.1 for giving a warning when X direction and Y direction
camera-shake sensors Sx and Sy are not in the operating state.
FIG. 2 is a block diagram showing a circuit of a camera according to the
present embodiment. Referring to FIG. 1, the camera according to the
present invention comprises a microcomputer .mu.C which controls the
entire camera and performs various operations, and has focus detecting
circuit AF.sub.CT connected thereto. Focus detecting circuit Af.sub.CT
comprises CCD, an integration control circuit, and an A/D converting
circuit, and gets information of an object from a focus detection area as
will be described later and A/D converts the information to output the
result to microcomputer .mu.C. The main parts shown in the circuit block
of a camera according to the present invention will be described below.
Brightness measuring circuit LM measures brightness in two areas described
later and A/D converts the measured brightness values to output the
results to microcomputer .mu.C as brightness information. Display control
circuit DISPC receives a display control signal from microcomputer .mu.C
to display a predetermined information in display portions DISP.sub.1 on
the upper surface of the camera body and DISP.sub.2 in a finder.
Camera-shake detector BL detects camera-shake as will be described later
in detail.
Microcomputer .mu.C is connected to electronic flash device ST, brightness
adjusting circuit STC which receives light reflected from an object
through an unshown taking lens at an emission of flash and stops the
emission of flash when an appropriate exposure amount is reached, and lens
circuit LE which outputs information specific to an interchangeable lens
to microcomputer .mu.C and drives an actuator for correction (a pulse
motor in the present embodiment) as will be described later, based on
correction amount information for camera-shake correction received from
the camera. Further, microcomputer .mu.C is connected to lens driving
control circuit LECN for driving a taking lens based on focus detecting
information, shutter control circuit TV.sub.CT for controlling shutter
based on a control signal from microcomputer .mu.C, aperture control
circuit AV.sub.CT for controlling aperture based on a control signal from
microcomputer .mu.C, motor control circuit MD for winding and controlling
a film based on a control signal from microcomputer .mu.C, battery E
serving as power source, reverse-current preventing diode D.sub.1,
large-capacity condenser C.sub.BU for backing up microcomputer .mu.C,
power supply transistor Tr1 for supplying power to part of the
above-described circuits, field-effect transistor FET (Tr2) for supplying
power to a motor for camera-shake correction.
In the following, description will be made on switches. Brightness
measuring switch S1 is used to perform various operations of camera (for
example, brightness measuring and display of various data) including
automatic focusing operation (referred to as "AF" hereinafter), and turned
on when an unshown release button is depresssed at a first stroke. When
light measuring switch S1 is turned on, microcomputer .mu.C executes an
interruption flow INT.sub.1 shown in FIG. 9A, as will be described later.
Main switch S.sub.M puts the camera in the operable state when turned on.
When this switch is turned on/off, interruption SMINT described later is
performed. Switch S.sub.IHBL is one for inhibiting camera-shake correction
and switch S.sub.SP is one for switching brightness measuring modes
(spot/average). Release switch S2 is handled when a picture is taken, and
turned on when the release button is depressed at a second stroke (deeper
than the first stroke). Switch X is a so-called X contact, and turned on
when a travel of preceding shutter curtain is completed and turned off
when an unshown release member is charged.
FIG. 3 is a flow chart diagram showing the interruption SMINT which is
performed when main switch S.sub.M is turned on/off. Referring to FIG. 3,
when this interruption is to be made, first, microcomputer .mu.C resets
all flags and data (to 0) (step #5) (in the following, the designation of
step will not be repeated). Then, determination is made as to whether main
switch S.sub.M has been turned on or not. When the switch has been turned
on, data is entered from the lens (#10 and #15). In this embodiment, the
data includes focal length f, coefficient K.sub.L for converting defocus
amount into lens driving amount, object distance DV, fully open aperture
value AV.sub.0 and a data representing presence or absence of lens.
FIG. 4 is a flow chart diagram showing the subroutine of data input at #15
shown in FIG. 3. Referring to FIG. 4, in the subroutine of data input,
data indicative of mode (I) (data input) is set (#180), potential at
terminal CSLE is set to the L level (#182), the data set as described
above is output (#185), the above-described data such as focal length f
are entered from the lens (#190), and then potential at terminal CSLE is
set to the H level (#195). It is to be noted that the mode (I) is a
control mode for the lens, subroutine LESIO (I) denoted in FIG. 4
represents data input to the camera, and LESIO (II) shown in FIG. 5 is a
mode for outputting data from the camera.
Turning back to the flow chart of FIG. 3, determination is made, based on
the data entered from the lens, as to whether a lens has been mounted or
not (#20). When one has been mounted, potential at terminal PW1 is set to
the H level so as to turn transistor Tr2 on (#25). Thus, power is supplied
to the driving motor for camera-shake correction. Data for resetting a
camera-shake correction is set and then the data is output to the lens
according to subroutine LESIO (II) (#35). The output data includes shake
amount in the X direction .DELTA.X, shake amount in the Y direction
.DELTA.Y and a data representing mode (reset/release/OFF).
Subroutine LESIO (II) for outputting data from the camera body to the lens
will be described with reference to FIG. 5. First, data of mode (I) is
reset (#200), voltage at terminal CSLE is set to the L level (#202), and
the above-described mode signal, i.e., mode (II) is output (#205).
Thereafter, the above-described output data is output (#210), potential at
terminal CSLE is set to the H level (#215), and then the program returns
to the main routine.
Subsequently, the operation proceeds to #42 in FIG. 3 (even in the case
that determination has been made at #20 that lens is absent, the program
proceeds up to this step), timer T is reset to start, a timer flag F1
indicative thereof is set, and then potential at terminal CHST is set to
the H level to start boosting of the electronic flash device ST (#40 to
#45). Thereafter, determination is made as to whether correction inhibit
switch S.sub.IHBL for inhibiting camera-shake correction has been turned
on or not (#50). When the correction inhibit switch S.sub.IHBL has been
turned on (correction is inhibited), data for inhibiting display is set
(#55) and the data is output to the display control circuit (#60) so as to
turn off the display indicating that camera-shake correction is being
made. Thereafter, the system waits until value of timer T reaches T2
(about 5 minutes) (#65), and then the program proceeds to step #125. At
step #125, the boosting of the electronic flash device ST is stopped,
potential at terminal CHST is set to the L level, data for turning on an
angular velocity monitor is reset and a signal indicative thereof is
output to camera-shake detector BL to turn off the monitor (#125 to #135).
Then, power supply transistors Tr2 and Tr1 are turned off, display data is
set, and a signal indicative thereof is output to the display circuit to
turn off the display. Thereafter, a timer flag (timer F) is reset and then
the microcomputer stops its operation (#140 to #148).
At step #50, when the switch for inhibiting correction has not been turned
on, the program proceeds to step #70, where data for turning on the
angular velocity monitor is set. Then, a sensor mode A is selected and
data indicative thereof is set and output to camera-shake detector BL (#70
to #80). Meanwhile, there are two sensor modes A and B. In the sensor mode
A, the angular velocity monitor for detecting camera-shake is turned on
only for a predetermined time, and in the sensor mode B, the angular
velocity sensor is always in the on-state. The purposes of providing the
two sensor modes are to reduce consumption current and also to make the
angular velocity sensor work only when it is required as in taking a
picture.
Next, contents of the subroutine BLSIO (I) shown at step #80 will be
described, where data is output to camera-shake detector BL. The data
output at this step is as follows.
angular velocity monitor: ON/OFF
sensor mode: A, B, OFF
focal length: f
object distance data: DV
FIG. 6 is a flow chart diagram showing the subroutine. Referring to FIG. 6,
in the subroutine BLSIO (I) where data is output to the camera-shake
detector, first, data mode is set to mode (I) for data input, potential on
terminal CSBL is set to the L level (#220 and #222), and then the data is
output (#225). Subsequently, data indicative of whether the
above-mentioned angular velocity monitor has been turned on/off is output,
potential on terminal CSBL is set to the H level, and then the program
returns to the main routine (#230 and #235).
Returning now to the flow chart shown in FIG. 3, the system waits until the
angular velocity sensor is stabilized to start measuring and then data
therefor is entered (#85 and #90). The data output from the camera is as
follows.
.DELTA.X.sub.BL : correction amount in the X direction
.DELTA.Y.sub.BL : correction amount in the Y direction
: camera-shake amount is large/not large
FIG. 7 is a flow chart diagram showing the subroutine BLSIO (II) at step
#90 shown in FIG. 3, where camera-shake amount is output from camera to
lens. Referring to FIG. 7, in the subroutine BLSIO (II), data of mode (I)
is reset (returning to mode (II) indicative of data output), potential on
terminal CSBL is set to the L level and data indicative thereof is output
(#240 to #245). Subsequently, data from camera-shake detector BL is
entered in microcomputer .mu.C, potential on terminal CSBL is set to the H
level, and then the program returns to the main routine (#250 and #255).
Turning back to the flow chart shown in FIG. 3, determination is made as to
whether the above-mentioned timer T indicates no less than T1 (about 7
seconds, corresponding to the time taken for the angular velocity sensor
to be stabilized) or not. When T.gtoreq.T1, it is determined that the
angular velocity sensor has been stabilized, and then a flag indicative
thereof (detection OKF) is set, data indicative of a WAIT display is
reset, and data is output to the display circuit (#100 to #110).
The reason why the system waits for the angular velocity sensor to be
stabilized is that when power is supplied to the sensor, data representing
a correct shake amount can not be output immediately. This is true
particularly when a vibration-type angular velocity sensor is employed.
In FIGS. 8A and 8B, there are shown times required for output of the
angular velocity sensor to be stabilized after power is turned on. In FIG.
8A, it takes about one second for the stabilization of output after power
is turned on, while in the example shown in FIG. 8B, it takes about 8
seconds for the stabilization of output. In consideration of the level to
be used, a maximum waiting time of 7 seconds is set in the present
invention.
Turning back to the flow chart shown in FIG. 3, when T=T2 in timer,
detection OK flag OKF is reset to turn off the camera and the flow
following the above-described step 125 is executed (#115 and #125).
At step #95, when timer T has not yet reached T1, the program proceeds to
step #125 and the system waits for 500 m seconds. Thereafter, t is made
equal to T1-T, data of WAIT display is set and the above-mentioned t and
the data of WAIT display are output to the display control circuit, and
then the program proceeds to step #75 (#115 to #170).
As described above in connection with steps #95 to #110 and #115 to #170,
according to the present invention, a display that photographing is
"waited" is made after the turning-on of main switch SM until time T1
taken for the angular velocity sensor to be stabilized has passed. When
the time taken for the angular velocity sensor to become stable has
passed, the display is reset. As a result, a photographer can determine
whether the angular velocity sensor for detecting camera-shake is
operating or not. Therefore, when the camera-shake detecting sensor is not
operating, pictures are not taken, thus preventing blurred pictures being
taken.
Subsequently, a program executed when brightness measuring switch S1 is
turned on will be described below. FIG. 9A is a flow chart diagram showing
the program executed when brightness measuring switch S1 is turned on.
First, potential on terminal FLOK for indicating that flash emission is
possible is set to the L level, and all display data is reset (#260 and
#265). Then, determination is made as to whether main switch SM has been
turned on or not. If the switch has been turned off, microcomputer .mu.C
stops (#275). If the switch has been turned on, transistor Tr1 is turned
on to supply power to brightness measuring-and AF circuits and the like,
flag AFEF indicating the in-focus state and flag MDF indicating that
camera-shake amount is large after the in-focus state is achieved are
reset, and then determination is made as to whether the correction inhibit
switch has been turned on or not (#280 to #290). When correction inhibit
switch S.sub.IHBL has been turned on at step #290, the program proceeds to
step #475 to set display inhibit data and further proceeds to step #395 to
execute the flow following thereafter (#475), details of which will be
described later.
When the correction inhibit switch has been turned off at step #290, the
program proceeds to step #295 and determination is made as to whether a
flag indicating that the angular velocity sensor can perform detection, or
detection OK flag OKF has been set or not. When the flag has been set, the
program proceeds to step #300 to set data of monitor ON. Subsequently, a
flag indicating that the sensor is in the A mode is set, data indicative
thereof is output to camera-shake detector BL, and then the system waits
for a certain time (10 m second). Thereafter, data of camera-shake amount
is entered from the above-mentioned detector BL and the program proceeds
to step #395 (#305 to #320). From the original purpose of correcting
camera-shake which takes place at the time of exposure, operation of the
camera-shake detecting sensor may not be started until release switch S2
is turned on. However, if the switch of the camera-shake detector is
turned on before release switch S2 is turned on, as shown in this flow,
its rising time can be reduced. When the detection OK flag indicating that
the angular velocity sensor can perform detection has not been set at step
#295, i.e., when the sensor has not yet been stabilized, data indicating
that the monitor is ON and data indicating that the sensor is in the A
mode are set and output to camera-shake detector BL to reset display
inhibit data, and then data is entered from lens (#330 to #345). It is
determined from the entered data whether a lens has been mounted or not.
When a lens has been mounted, transistor Tr2 is turned on to supply power
to the motor for correction on the lens side, lens mode is reset,
information indicative thereof is output to the lens, and then the program
proceeds to step #370 (#350 to #365). Even when no lens has been mounted
at step #360, the program proceeds also to step #370.
At step #375, determination is made as to whether the timer flag has been
set or not. When the flag has been set, the program proceeds to step #376.
When the timer flag has not been set, the timer-flag is set, timer T is
reset to start, and then the program proceeds to step #376 (#370 to #374).
At step #376, determination is made as to whether timer T has reached a
value no less than T1 or not. When T.gtoreq.T1, the detection OK flag is
set, WAIT display is reset, and the program proceeds to step #395 (steps
#376 to #385). On the other hand, when T<T1, it is determined that the
angular velocity sensor has not been yet stabilized. Then, operation is
made to make t equal to T1-T, WAIT display data is set, and then the
program proceeds to step #395.
At step #395, data is entered from lens, brightness is measured, and then
AF operation is performed. Exposure operation (AE operation) is performed
based on the measured brightness data to stop down aperture, and a shutter
speed is found (#400 to #410). Those respective subroutines will be
described later.
As described above in connection with steps #376 to #390, according to the
present invention, also in an interruption flow where the brightness
measuring switch is turned on, WAIT display is made at the display portion
of camera after the turning-on of the brightness measuring switch until
the angular velocity sensor is stabilized, and after the time taken for
the angular velocity sensor to be stabilized has passed, the display is
reset. Therefore, as previously described, before the camera-shake
detecting sensor becomes stable, it is displayed that the camera-shake
detecting sensor has not been yet stabilized. Accordingly, a photographer
does not take pictures in such a state. As a result, a camera capable of
photographing unblurred pictures can be provided.
Meanwhile, according to the present invention, as shown at step #325, when
the detection OK flag indicating that camera-shake can be detected
represents NO, ON data is set for the camera-shake detecting monitor.
Accordingly, at the same time that the brightness measuring switch is
turned on, the sensor circuit of the camera-shake detector is turned on.
Subsequently, the brightness measuring subroutine shown at step #400 in
FIG. 9 will be described with reference to FIG. 10. In FIG. 11, there is
shown a brightness measuring pattern as viewed from a finder. As shown in
FIG. 11, the brightness measuring pattern is composed of two areas; one is
spot brightness measuring area BV.sub.SP at the center and the other is
peripheral brightness measuring area BV.sub.AM surrounding the former.
Brightness values measured from the respective areas are represented as
BV.sub.SP and BV.sub.AM.
Referring to FIG. 10, data of values BV.sub.SP and BV.sub.AM measured in
the respective areas are entered and determination is made as to whether
the spot brightness measuring switch has been turned on or not. When the
switch has not been turned on, the measured value BV is set to (BV.sub.AM
+BV.sub.SP)/2 and then the program returns to the main routine (#480 to
#490). On the other hand, when the spot brightness measuring switch has
been turned on at step #485, determination is made, based on the data
entered from camera-shake detector BL, as to whether the camera-shake
amount is large or not. When the camera-shake amount is large, the data is
not updated but the program returns to the main routine. When the
camera-shake amount is small,BV.sub.SP is substituted for the measured
value BV and then the program returns to the main routine (#495 to #500).
The reason why the data is not updated in the case of a large camera-shake
amount is that deviation of measured values should be prevented which
might take place when a brightness measuring range is shifted due to a
momentary camera-shake.
Subsequently, the AF subroutine shown at step #405 in FIG. 9 will be
described below. FIG. 12 is a flow chart diagram showing contents of the
AF subroutine. Referring to FIG. 12, first, integration of CCD is done,
data is entered, and then current defocus amount DF1 is calculated based
on the entered DF amount for driving lens (#505 to #515). At step #520,
determination is made as to whether flag MDF indicating that camera-shake
amount is large after the in-focus state is achieved has been set on or
not. If MDF has been set, the program returns immediately to the main
routine (#520). Thus, when the camera-shake amount after achievement of
the in-focus state is large, determination of a moving object is inhibited
and AF lock is made. This is because AF information can not be relied on
when the camera-shake amount is large.
On the other hand, when flag MDF has not been set at step #520,
determination is made as to whether flag AFEF indicative of the in-focus
state has been set or not (#525). When the flag has not been set,
determination is made as to whether camera-shake amount is large or not
(#530). When the camera-shake amount is large, reliability of the defocus
amount is low. Therefore, the program returns to the main routine without
driving lens. When the camera-shake amount is not large at step #530, the
obtained defocus amount DF1 is set as defocus amount DF for lens drive.
When the defocus amount is not below a predetermined value, lens drive
amount is taken by multiplying the DF amount by coefficient for converting
lens drive amount so as to perform lens drive, and then the program
returns to the main routine (#535, #540, #555 and #560). When the defocus
amount DF for lens drive is below the predetermined value at step #540,
flag AFEF indicative of the in-focus state is set, N is set to 0, and then
the program returns to the main routine (#545 and #550).
When flag AFEF indicative of the in-focus state has been set at step #525,
the program proceeds to step 570 and the current defocus amount DF1 is
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