JP2973443B2 - camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera for detecting blur, and more particularly to a TTL camera.
The present invention relates to a camera shake detection camera.

[Prior Art] Conventionally, a camera having an electronic finder is disclosed in
It is disclosed in JP-A-62-35329. However, the conventional camera with an electronic finder has not been equipped with a shake detecting device.

On the other hand, a camera with an electronic finder capable of detecting blur is disclosed, for example, in Japanese Patent Application Laid-Open No. 63-129328. According to the publication, a camera with an electronic viewfinder capable of detecting blur includes an area CCD sensor for blur detection, and detects blur by comparing an image at a certain time with an image at another time. However, the conventional shake detection camera with an electronic finder is an external light type and not a TTL type.

On the other hand, a video camera that performs blur correction by the TTL method is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-240778. According to the publication, a video camera detects a blur of an image using an angular velocity sensor and corrects the blur by moving a lens.

[Problems to be Solved by the Invention] Conventional cameras with an electronic finder and a shake detection device, and video cameras of the TTL system have been configured as described above. Therefore, still cameras have parallax because they are not of the TTL type. As a result, it has been difficult to correct image blur. Furthermore, in the case of a TTL video camera, there is no need to consider the optical path because it is not a still camera.

The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a camera capable of confirming display of a subject image before and after a shooting start instruction and confirming the presence or absence of blur during shooting. I do.

Means for Solving the Problems According to the present invention, a camera provided with a photographing optical system for guiding light from a subject and forming an image of the subject on a predetermined surface is provided. Provided in the light path,
A semi-transmissive mirror that splits light from the subject, a two-dimensional area sensor that receives one of the light from the subject split by the semi-transmissive mirror, and converts the light into an electric signal, and an output signal of the two-dimensional area sensor. Based on the output signal of the two-dimensional area sensor, a display unit for electrically displaying a subject image based on an output signal of the two-dimensional area sensor, a unit for instructing a start of photographing, Causes the display means to sequentially display the subject image on the basis of a signal repeatedly output from the area sensor, and after the instruction to start shooting, the blur detecting means based on the output signal of the two-dimensional area sensor during shooting. And control means for performing blur detection and causing the display means to display a subject image.

[Operation] In the present invention, the display unit sequentially displays the subject image before the instruction to start shooting, and after the start instruction,
In addition to causing the blur detection means to detect blur,
The subject image is displayed. Therefore, before starting shooting, you can check the viewfinder image that is repeatedly displayed in a loop,
After the start of shooting, it is possible to visually check whether or not there is blur.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main part of an electronic viewfinder-equipped shake detection camera according to the present invention.

Referring to FIG. 1, a photometric SPD (Silicon Photodiod
e) The signal from 2 is input to the photometric circuit 31. Photometry circuit 3
1 calculates the output of SPD2 and outputs the calculation result to the main CPU1. The photographing lens 3 is exchangeable, and the aperture is driven and the focus is adjusted through the aperture driving means 4 and the focus adjustment driving means 5. The photographing lens circuit 6 stores an F-number, a focal length, and various parameters for blur correction of the lens unique to the photographing lens 3. The photographing lens circuit 6 further includes an actuator for driving an optical system for blur correction and a control circuit therefor.

The AF detection mirror 7 guides a part of the light beam that has passed through the photographing lens 3 to the phase difference type AF detection module 14. AF detection mirror 7
AF does not block light to film during film exposure
It is retracted by the detection mirror driving means 8. The shutter curtain 9 of the focal plane shutter includes a front curtain and a rear curtain, and is driven by a shutter curtain driving unit 10. The switch S1 is turned on at the first stroke of the shutter button to perform photometry and AF operation. The switch S2 is turned on by the second stroke of the shutter button. The film winding means 15 winds and rewinds the film. Switches S1 'and S2' are shutter buttons provided on a remote finder described later, and have the same function as switches S1 and S2, respectively. The switch SC is a switch for operating the continuous shooting mode.

Blur detection optical system 40 and shooting optical system for electronic viewfinder
Reference numeral 41 denotes an optical system that is driven by the shake detection optical system driving unit 42 and guides light to a later-described shake detection CCD. The blur detection optical system 40 is used when performing blur detection, and the electronic finder imaging optical system 41 is used when displaying an image using the above-described CCD. The main CPU is further connected to a camera shake correction controller 18 for detecting camera shake described later. The camera shake correction controller 18 communicates with the camera shake detection and correction means 11.

The CPU further includes an exposure correction amount input means 22 for performing exposure correction on the exposure amount determined by the photometric value,
Film sensitivity setting means 23 for setting film sensitivity
Are connected.

Next, the electronic finder will be described. Figures 2A to 2D
The figure shows the usage of the electronic finder. Referring to FIG. 2A, a detachable and movable electronic finder 100 is provided on the upper surface of the camera body 12. The electronic finder 100 includes an LCD 63 for displaying a finder image, and a shutter button 101. When the electronic finder 100 is used as shown in FIG. 2A, it is used as a waist level finder. FIG. 2B is a diagram showing a state where the electronic finder 100 is raised toward the user. You can see the viewfinder image without looking through the viewfinder eyepiece. Therefore, it is possible to take a picture while checking the viewfinder image from around the chest to the height at which the camera is held above the head. FIG. 2C is a view showing the electronic viewfinder 100 raised forward. Self-timer shooting can be performed while checking the viewfinder image. In this case, LC for viewfinder image display
The D63 image is upside down from the normal case. FIG. 2D is a diagram showing a state in which the electronic finder 100 is detached from the camera body 12. By using the electronic finder extension cord 102, the release button 101 can be used for remote photography while observing the finder image on the LCD 63.

The image signal to the LCD 63 is picked up by the CCD pick-up unit 51 of the shake detection sensor 44 described later with reference to FIG. At this time, the exposure time of the CCD is determined based on the exposure of the camera. Therefore, an image close to the density of the completed photograph is displayed on the LCD 63. When performing exposure correction during photographing by auto exposure, the exposure correction amount input means 22 may be adjusted so that a portion to which exposure is to be mainly adjusted can be observed with good gradation while looking at the LCD 63. The exposure setting at the time of shooting by manual exposure may be adjusted by adjusting the aperture and the shutter speed so that a portion to be mainly exposed can be observed with good gradation while watching the LCD 63. In addition, even when intentionally overexposure or underexposure is desired, if the exposure is determined while observing the LCD 63, a photograph having the intended exposure can be easily obtained.

FIG. 3A is a diagram showing an optical system of a camera shake detection camera with an electronic finder according to the present invention. Referring to FIG. 3A, photographing lens 3 includes a blur correction lens 32, and a blur correction lens driving device 33 for moving blur correction lens 32. Since the details of the correction lens driving device 33 are known, the description thereof is omitted. A pellicle mirror 34 is fixed in the camera body 12, and a part of the light beam that has passed through the photographing lens 3 is reflected toward the finder optical system, and the rest is transmitted toward the shutter curtain 35. Part of the light beam transmitted through the pellicle mirror 34 is guided by the AF detection mirror 7 toward the phase difference AF detection module 36. The AF detection mirror 7 is retracted by the AF detection mirror driving means 8 (not shown) to a position where the light flux during exposure that reaches the film during exposure of the film is not blocked.

The light beam reflected by the pellicle mirror 34 passes through the condenser lens 37 and enters the pentaprism 38. On the eyepiece 39 side of the pentaprism 38, a photometric SPD2 is provided. One surface 38a of the pentaprism 38 is a half mirror, and takes out a part of the incident light beam out of the pentaprism 38. The extracted light flux passes through a blur detection optical system 40, is reflected by a reflecting mirror 43, and reaches a blur detection sensor 44. The blur detection optical system 40 and the imaging optical system 41 for an electronic finder are driven by a blur detection optical system driving means 42, and are selectively put in and out of the optical path. The blur detection optical system 40 and the electronic finder imaging optical system 41 re-image the image on the finder focal plane 45 on the blur detection sensor 44, respectively. The blur detection sensor 44 is a CCD area sensor. The pentaprism 3
8 may be not only a glass block type but also a hollow pentamirror having an air layer inside.

As described above, in the present invention, the pellicle mirror 34
Is used to transmit the light of the subject to the area sensor 44 serving as a blur detection sensor, so that the camera of the TTL system detects the blur by the image detection system. Further, since the pentaprism 38 is used in the optical path to the blur detection sensor 44, there is no need to provide a separate optical path to the blur detection sensor 44.

FIG. 3B is a diagram showing details around the shake detection optical system driving means 42. Referring to FIG. 3B, the lens 40a of the blur detection optical system 40 and the imaging optical system
Lens holders 200 and 201 to which one lens 41a is fixed are fixed, and are connected to a motor 210 via gears. Motor 2
The shaft of 10 is interlocked with the disk-shaped chopper 202 via a gear,
The rotation of the encoder spring 202 is read by a photocoupler 203. When the encoder spring 202 rotates, an on / off signal is generated each time light between the arms of the photocoupler 203 is cut off. The controller 204 counts this pulse signal. As a result, the amount of rotation of the rotating shaft is monitored. By turning on or off the energization of the motor 210 according to the monitored signal, the lenses 40a and 41a of the blur detection optical systems 40 and 41 are rotated. In this way, the shake detecting optical system driving unit 42 switches the optical path between the shake detecting optical system 40 and the electronic finder imaging optical system 41.

As described above, in the present invention, the optical system for projecting the subject image onto the blur detection sensor 44 is switched by the blur detection optical system driving means 42. As a result, the pixel area used for blur detection and the AF area selected for focusing are switched.

4A to 4C are views showing a finder screen. 4A and 4A are transparent blur detection areas,
The presence of this region secures an optical path to the sensor 44 and increases the amount of light to the sensor 44. The area represented by c is a mat portion of the finder screen, where light is scattered, an image is formed thereon as in the past, and focus is detected. The area indicated by a is also used for displaying the finder display frame of the blur detection area. FIG. 4B shows the visual field range of the electronic finder, which is also transparent, so that the amount of light to the image finder imaging optical system 41 increases. No.
FIG. 4C is a diagram showing a case where the entire surface of the finder screen is transparent.

A part a near the center of the finder screen c is imaged on the imaging surface by the shake detection optical system 40. This image is used by the blur detection sensor 44. Further, when the imaging optical system 41 for an electronic finder is used, the finder screen c
Is formed on the imaging surface, and the image is used as an image for the electronic finder.

Referring to FIG. 3A, the taking lens 3 is attached to the camera body 12 via a lens mount 46, and can be replaced.

When a normal lens without a camera shake correction lens is attached to the camera body 12, a warning is displayed on the finder screen when blur is detected. A warning of camera shake may be given to the electronic finder with the text “Caution for camera shake”.

FIG. 5 shows another embodiment of the optical system according to the present invention.
In this case, the pentaprism 38 is omitted as compared with the optical system shown in FIG. 3A. Since there is no pentaprism 38, finder screen, condenser lens 37,
The cost can be reduced, and it is lighter and more compact. A sensor re-imaging lens 45 'is provided in front of the blur detection sensor 44'. The small-area relay lens 40 'and the large-area relay lens 41' are used by switching, whereby the light flux guided to the area sensor 44 'is switched. In the optical system according to this embodiment, the reflection mirror 4
3 ', an optical system drive actuator 42' is provided.

6A and 6B are views showing a use state of a finder screen when the optical system according to another embodiment of the present invention shown in FIG. 5 is used. These figures correspond to FIGS. 2A to 2D according to the first embodiment. Referring to FIGS. 6A and 6B, electronic finder 63 is removable.

Next, the contents of the camera shake detection and correction means 11 will be described with reference to FIG. The camera shake detection sensor 44 includes a CCD imaging unit 51, an output amplifier 52 for amplifying a CCD output, an illuminance monitor 53 for controlling the integration time of the CCD, and a photometric circuit 54. The clock generator 55 detects the output of the photometry circuit 54 and
Set the integration time and gain of the output amplifier. The clock generator 55 is used to drive the CCD drive clock, A / D
Clocks for the converter 61, the D / A converter 58, the sensitivity variation correction memory 59, and the dark output correction memory 60 are also generated. The output of the shake detection sensor 44 is input to the A / D converter 61 through the differential amplifier 56 and the gain control amplifier 57. Dark output correction memory 60, sensitivity variation correction memory 59
Stores data for correcting variations in CCD sensitivity and dark output. The dark output correction memory 60 has a D /
Data is output to A converter 58. The output signal of the D / A conversion is input to the differential input of the differential amplifier 56. Thereby, the dark output of the CCD 51 is corrected. The gain control amplifier 57 is an amplifier whose amplification is controlled by a digital signal. The gain control amplifier 57 is controlled by sensitivity variation correction data stored in the sensitivity variation correction memory 59, and corrects the sensitivity variation of the CCD output.

The output signal of the A / D converter 61 is stored in the image section memory 64, the reference section memory 65, or the reference section memory 66. The address generator 67 generates address data necessary for the operation of each of the image memory 64, the reference unit memory 65, and the reference unit memory 66.

The arithmetic unit 68 includes a subtraction circuit 69, an absolute value circuit 70, and an addition circuit
71 and a register 72 are included. Data of the reference section memory 65 and the reference section memory 66 are provided as inputs.

The calculation result from the calculator 68 is stored in one of the correlation result memory 73, the vertical contrast memory 74, and the horizontal contrast memory 75 depending on the type of calculation. These memories are connected to the control CPU 76 and can be accessed from the control CPU 76. The control CPU 76 also controls the address generator 67 and the clock generator 55. The data in the image memory 64 is stored in the D / A converter 77
/ A conversion and input to the video signal processing circuit 62. The switch SRV is turned on when the LCD 63, which is an electronic finder, is raised forward. When this switch is turned on, the video signal processing circuit 62 displays the video on the LCD 63 with the upside down.

Next, a method of shake detection and calculation of a shake amount will be described. First, a blur detection sequence will be described. In the present invention, an area sensor capable of detecting two-dimensional image data
The object image is detected two-dimensionally using 44. The image blur is detected by detecting the time-dependent shift of the subject image using the area sensor 44.

The CCD 51 is an area sensor of I × J pixels. The reference unit memory 65 and the reference unit memory 66 are each a memory of I × J words, and the correlation result memory 73 is a memory having a capacity of H × H words. The light receiving surface of the CCD 51 is divided into M × N blocks. Each block is composed of adjacent K × L pixels. The vertical contrast memory 74 and the horizontal contrast memory 75 are memories each having a capacity of M × N words. Hereinafter, the procedure of blur detection will be described. Here, I = 68, J = 52, K = 8, L = 8, M = 8, N = 6,
Let H = 5. The resolution of the A / D converter 61 is 8 bits and the register 72 is 14 bits.
3, vertical contrast memory 74, horizontal contrast memory 75
Is represented by 14 bits.

FIG. 8 is a schematic view of a part of the light receiving section of the CCD 51. One small square grid represents a unit pixel. In the figure, the lower left pixel is a pixel (1, 1), and the upper right pixel is a pixel (68, 52). CCD5 excluding the two pixels on the outer periphery of the light receiving section
One light receiving section is divided into blocks each composed of 8 pixels × 8 pixels. The portion surrounded by a thick line in the figure corresponds to each block. The lower left block is a block (1, 1), and the upper right block is a block (8, 6).

 The blur detection sequence is roughly divided into three parts: (1) contrast calculation and block selection (2) correlation calculation (3) interpolation calculation.

The contrast calculation is a calculation performed for selecting a block. Each part of the subject imaged on the light receiving part of the CCD 51 includes a part suitable for blur detection and a part not suitable for blur detection. In this embodiment, the contrast of the subject is calculated in order to select a portion suitable for blur detection. The contrast of the subject is calculated for each block, and blur detection is performed using a total of eight blocks, four blocks with high contrast in the vertical direction and four blocks with high contrast in the horizontal direction.

(1) Description of Contrast Calculation and Block Selection First, the output of the CCD 51 is stored in both the reference memory 65 and the reference memory 66. Using this data, the vertical and horizontal contrasts of each block are calculated. The calculation is for blocks (1,1), (2,1),…,
(7,6), (8,6) horizontal contrast, block (1,
1), (2, 1),... (7, 6), and (8, 6) are performed in the order of vertical contrast.

Assuming that the output of the pixel (i, j) of the CCD 51 is A (i, j), the horizontal contrast of the block (k,) is The procedure for executing this formula using the hardware shown in FIG. 7 will be described below. The contents of the reference part memory 65 corresponding to the output of the pixel (i, j) of the CCD 51 are R (i, j), and the contents of the reference part memory 66 are S (i, j). First, the register 72 is cleared. Next, R (i, j) is input to one input of the subtracter 69, and S (i + 1, j) is input to the other input, where i = 8 (k-1) +
2, the address is sent from the address generator 67 so that｝ is set to j = 8 (−1) +2. Subtraction circuit
The data subtracted at 69 is taken by the absolute value circuit 70 to obtain an absolute value, added to the content of the register 72 by the adder circuit 71, and stored in the register 72. Next, an address to be i = i + 1 is transmitted from the address generator 67, and the same calculation is performed. Thus, i = 8 (k-1) +2 to 8k + 2,
When processing is performed in the range of j = 8 (-1) +3 to 8 + 2, the register 72 stores The same contents A (i, j) are stored in the reference part memory 65 and the reference part memory 66, and A (i, j) = R (i, j) =
Since it is S (i, j), the contents of the register 72 are the horizontal contrast. It is. When the calculation for one block has been completed, the contents of the register 72 are transferred to the corresponding portion of the horizontal contrast memory 75 and stored.

Similarly, the horizontal contrast of all the remaining blocks is calculated and stored in the horizontal contrast memory 75.

Next, the vertical contrast is calculated. As in the case where the lateral contrast was calculated, first register 72
Is cleared. Next, R (i,
j), and the other input is S (i, j + 1) where i = 8 (k−
1) +3, j = 8 (−1) +2, and the address is sent from the address generator 67 so that｝ is given.
The data subtracted by the subtraction circuit 69 has an absolute value obtained by an absolute value circuit 70, is added to the contents of a register 72 by an addition circuit 71, and is stored in the register 72. Next, an address to be i = i + 1 is sent from the address generator 67, and the same calculation is performed. Thus, i = 8 (k-1) +3
The processing is performed in the range of 88k + 2, j = 8 (−1) +2 to 8. As a result, the register 72 contains Is stored. Where A (i, j) = R (i, j) = S
Since (i, j), the contents of register 72 are the vertical contrast. It is. When the calculation for one block is completed, the contents of the register 72 are transferred to a location of the vertical contrast memory 74 corresponding to the block and stored.

Similarly, the vertical contrast of all the remaining blocks is calculated and stored in the vertical contrast memory 74.

The control CPU selects the block having the highest contrast from the vertical and horizontal contrasts of each block obtained as described above. Next, a block having the highest contrast is selected from the remaining blocks in a direction different from the previously selected contrast direction (for example, in the case of the vertical direction in the case of the vertical direction, the horizontal direction). In the same manner, eight blocks (four in each of the vertical and horizontal directions) are selected in the order of the blocks having the highest contrast while changing the direction of the contrast. The selected blocks are B1 to B8.

(2) Description of Correlation Calculation As the contents of the reference portion memory 65, data on which contrast has been calculated is left as it is as reference image data. New data is read from the CCD 51 one after another, and each time it is written into the reference memory 66 as a reference image.
Each time new data is written to the reference section memory 66, the reference image and the reference image are compared, and a spatial shift between the two is detected as image blur. Image blur is obtained by correlation calculation and interpolation calculation described below.

The block Bk (k = 1, 2,... 8) correlation value is defined by the following equation.

(I _k , j _k represent the youngest pixel number in block Bk) = m = 0 Becomes This value is obtained by adding the absolute value of the difference between the data of the same pixel in the reference image and the reference image for one block.
= M = 0, Ck (, m) is the data of pixel (i, j) of the reference image and pixel (i +
, j + m) is obtained by adding the absolute value of the difference with the data of one block. The correlation value obtained by adding the correlation values for 8 blocks And

One input of the subtraction circuit 69 is connected to the reference unit memory 65, and the other input is connected to the reference unit memory 66. Therefore, after clearing the register 72, R (i, j) and S (i +, j + m) are input to one input of the subtraction circuit 69, and data in a predetermined range of i and j is processed. Then, the address determined by the control CPU is transmitted from the address generator 67. Then, register 72 contains C
(, M) is obtained. This is transferred to a predetermined address of the correlation result memory 73 and stored. , m is changed and the above processing is repeated to obtain C (,
m): (, m = -2, -1,0,1,2) are all obtained.

(3) Description of Interpolation Calculation When the calculated correlation values C (, m) are arranged on the horizontal axis and m is arranged on the vertical axis, an array like a number is obtained.

C (−2,2) C (−1,2) C (0,2) C (1,2) C (2,2) C (−2,1) C (−1,1) C (0,1) 1) C (1,1) C (2,1) C (−2,0) C (−1,0) C (0,0) C (1,0) C (2,0) C (−2 , -1) C (-1, -1) C (0, -1) C (1, -1) C (2, -1) C (-2, -2) C (-1, -2) C (0, -2) C (1, -2) C (2, -2) If there is no deviation between the reference image and the reference image,
(0,0) becomes 0, and the value becomes larger toward the outside of the array. Further, ₀ pixels to the right with respect to the reference image in the reference image, when deviated m ₀ pixels above, C _(0,
m ₀ ) becomes 0, and has a larger value as it goes away from it. However, the image shift is not always an integral multiple of the pixel. Further, since the speed of the image blur is not constant, the blur of the image due to the image blur may be different between the reference image and the reference image. FIG. 9 shows how the distribution of the correlation value C (, m) in such a case is represented by contour lines. Referring to FIG. 9, values are actually obtained only on grid points in the figure, but contour lines are drawn assuming values between grids.
The contour lines have smaller values toward the center. The center of the contour line is the MP point at the coordinates (x ₀ , y ₀ ), and the reference image is considered to be shifted by x ₀ horizontally and y ₀ vertically with respect to the reference image. Since only the values on the grid points are obtained by the correlation calculation, the MP points need to be obtained by interpolation using the data of the grid points. As for the magnification of the blur detection optical system 40, the pixel size of the CCD 51, and the integration time, the MP point is −1.5 <x ₀ , y ₀ assuming the actual magnitude of the blur.
It is set to be <1.5.

The interpolation calculation after the completion of the correlation calculation will be specifically described. The calculation in the horizontal direction will be described. First find C (, m) minimum value C of _(0, m _0). The value of ₀ and C (
_0-1 , m ₀ ) and C ( _{0 + 1} , m ₀ ) are classified into the cases shown in FIGS.

(A) In the case of condition It is determined that 0 ≦ x ₀ <1.

A straight line (i) connecting the point (−1, C (−1, m ₀ )) and the point (0, C (0, m ₀ )), the point (1, C (1, m ₀ )), and the point (2, C (2, m ₀ ))
The coordinates of an intersection between a straight line (ii) connecting the x _0.

(B) In the case of condition It is determined that 1 <x ₀ <0.

A straight line (i) connecting the point (−2, C (−2, m ₀ )), (−1, C (−1, m ₀ )), and the point (0, C (0, m ₀ )) , Point (1, C (1,
m ₀₎₎ the coordinates of an intersection between a straight line (ii) and x ₀ connecting.

(C) In the case of condition It is determined that 0 <x ₀ <1.

The following is the same as in the case of (a), (D) In case of condition It is determined that 1 ≦ x ₀ <2.

A straight line (i) connecting the points (0, C (0, m ₀ )) and (1, C (1, m ₀ )), and a straight line (i, i) passing through (2, C (2, m ₀ )) ) and the coordinates of an intersection of the opposite sign of the linear (ii) and x _0.

(E) In the case of the condition: It is determined that −1 ≦ x ₀ <0.

The following is the same as in the case of (b), (F) In the case of the condition: It is determined that −2 <x ₀ <−1.

Point (-1, C (-1, m 0)) through the point (0, C (10, m 0)) and linear (ii) through line (-2, C (-2, m 0)) , slope to the coordinates of the intersection of the straight line (ii) the opposite sign of the straight line (i) and x _0.

In the case of the conditions (g) and (h), it is determined that a shake exceeding the assumed maximum shake has occurred and that the shake amount cannot be detected.

While illustrating a procedure for obtaining the above x _0, it can be obtained in the same for y _0.

Next, a method of driving the correction lens 32 shown in FIG. 3A will be described. FIG. 11 is a diagram for explaining a method of driving the correction lens 32. Here, only the horizontal component of the image blur is considered. In FIG. 11, the horizontal axis t represents time, and the vertical axis x
Represents the position of the image, t _-3 , t _-2 , t _-1 ,... Represent the CCD 51 integration start time, and t _-3 ″, t ₋₂ ″, t ₋₁ ″,. The integration time TI _i is represented by TI _i = t _i ″ −t _i . If the subject is illuminated with an AC light source, CCD5
The integration time is changed so that the exposure amount of 1 becomes constant.
Therefore, the integration time is not constant. Integration start time t
_-3 , t _-2 , t _-1 , ... are equally spaced T _s . Solid curve 301
Indicates the locus of the image on the CCD 51 when there is image blurring. If the blur correction by the correction lens 32 is not performed, the image moves on this curve. Since the blur correction starts at t = t ₀ , the curve 301 is drawn so as to pass through the point (t ₀ , 0). A polygonal line 302 is a locus of the correction lens 32. A broken line 303 represents the locus of the image on the CCD 51 when the correction lens 32 is moved to perform the correction. Points P _-2 , P _-1 ,
P ₀ ,... Are integration periods t _{−3 to} t ₋₃ ″, t ₋₂ to t ₋₂ ″, t ₋₁ to
t _-1 ", ... .t _i ~ which represents the average position of the image in
CCD data obtained by integrating between t _i "is read during _{t i + 1 ~t i + 2} , calculation processing is performed to seek from .t _{i + 2} position P _i of the image are obtained The correction lens 32 is driven by the obtained data.

In the following description, P _-2 , P _-1 , P ₀ , ..., X ₁ ,
X ₂ , X ₃ ,…, X ₁ ′, X ₂ ′, X ₃ ′,…, X ₀ ″, X ₁ ″,
X ₃ ″,... Are the names of the points and are also used as the x-coordinate values of the points.

In order to perform the correction from the time t = t _0, it is necessary to find the speed of the blur between t ₀ and t ₁ . Change obtain a speed of the motion from the image position of the last two points, predicts the rate of blur between t ₀ ~t ₁ is also simultaneously therewith. The latest image position known at time t = t ₀ is P ₋₁ . Since the time from P _-2 to P _-1 is _{TS- (TI -3 -TI -2) /} 2, t 0 ~t 1 of the predicted value V _x0 velocity of blurring It is. Thus, between t ₀ ~t _1, the correction optical system is driven at a speed of V _x0.

Next, consider the case of time t = t _1. At this time the correction lens
Since 32 is driven by V _X0 , it is moved to the position of X ₀ ″. At this time, since the position of P ₀ has been changed, the predicted value V _x1 of the blurring speed from t _{1 to} t ₂ is calculated as follows. Required.

Since the speed V _x1 is obtained based on the latest image position data, the predicted value of the blurring speed between t ₀ and t ₁ is V
_It is considered to be more accurate than _x0 . Therefore, the prediction error ER _x1
Is calculated as follows.

_{ER x1 = (V x0 -V x1} ) · TS position X ₁ of the image at t = t ₁ from these values are predicted as follows.

X ₁ = V _x0 · TS−G · ER _x1 = {V _x0 −G (V _x0 −V _x1 )} · TS G is referred to as a prediction coefficient. In FIG. It is shown. Here the correction lens 32 needs to be driven to the newly predicted X ₁ point, but the driving time is required for t ₁ ~t ₁ '. 'Because it is predicted to move to the position of the correction lens 32 X _1' statue X ₁ between them 'is driven to a position _{(-t 1, t 1 = X} 1 + V x1 × t 1)' ~t 2 Is driven at the speed of _Vx1 .

Next, consider the case of time t = t _2. . In this case the correction lens is moved to a position represented by _{X 1 "= X 1 + V} x1 · TS at this time, since the found position of P ₁ t ₂ -
The predicted value V _x2 of the blur speed during t ₃ can be calculated as follows.

V _x2 is considered to be more accurate than V _x1 as the predicted value of the shake speed between t ₁ ~t _2. Therefore, the prediction error ER _x2 is calculated as follows.

ER _x1 = (V _x1 −V _x2 ) · TS From these values, the position X ₂ of the image at t = t ₂ is predicted as follows.

X ₂ = X ″ G · ER _x2 = X ₁ + {V _x1 −G (V _x1 −V _x2 )} · TS Here, the correction lens 32 needs to be driven to the newly predicted position X ₂ , the driving 'is required time. during which the image is X _2' t ₂ ~t ₂ correction lens since it predicted to move to the position of the 32 _{X 2 '= X 2 + V} x2 · (t 2' -t It is driven to a position of _2), between t ₂ '~t ₃ is driven at a speed of V _x2.

Next, consider the case of time t = t _3. At this time the correction lens
X ₂ ″ is at a position represented by X ₂ ″ = X ₂ + _Vx2 · TS. Predicted value V _x3 displacement speed between t ₃ ~t ₄ because you know the position of P ₂ at this point can be calculated as follows.

(Where _{t = t 1 ~t = t 1} ' of time is ignored.) V _x3 prediction order is considered to be more accurate than V _x2 as the predicted value of the shake speed between t ₂ ~t ₃ error ER ₃ Is determined as follows.

_{ER 3 = (V x2 -V x3} ) · TS position X ₃ of the image at t = t ₃ from those values _{X 3 = X 2 "-G ·} ER x3 = X 2 + {V x2 -G (V _x2 -V _x3)} · TS and can be predicted. where the correction lens 32 should be driven to a position X ₃ newly predicted time is required between t ₃ ~t ₃ 'to drive . since it can be predicted that the image during moving to the position of X ₃ ", the correction lens 32 is driven to a position of _{X 3 '= X 3 + V} x3 · (t 3' -t 3), t 3 '~t 4 It is driven at a speed of _Vx3 .

Hereinafter, similarly, X ₄ , V _x4 , X ₅ , V _x5 ,... _Are obtained, and the correction optical system is driven.

In the present embodiment, the prediction coefficient G is fixed. However, the value of G may be changed during the correction sequence depending on the situation of blur detection. Even if the number of times of the motion compensation is performed, if the prediction error ER is not reduced, or when the sign of the prediction error ER _i is not inverted, the prediction coefficient G may be large. Further, when repeated inversion not endure the sign of the prediction error ER _i may the value of G is small.

With reference to FIG. 11, the time TR from time t ₀ to t _z is a photographic exposure time of the camera. As can be seen from FIG. 11, the sequence for performing the camera shake correction is repeated many times within the photographing exposure time TR. Therefore, the correction is not performed only once or twice, but is performed at least several times. Therefore, the actual camera shake amount calculation and correction calculation time need to be performed within a certain short time. In addition, the integration times TI ₃ , TI ₂ ,
… TI ₀ … TI _n must also be short. Exposure time TR
Is on the order of several tens to 1000 ms, TI _n is on the order of several ms. If this relationship is not maintained, the effect of camera shake correction will not appear.

As described above, in the present invention, blur detection is performed using the output of the area sensor that detects the subject image, and the above-described blur correction is performed using the detected blur amount.

Next, an interface between the interchangeable lens 3 and the camera body 12 will be described. From the interchangeable lens 3, correction magnifications KBLX and KBLY (values corresponding to respective focal lengths when zooming is performed): (amount of image movement on the film surface) / (driving pulse) are input as lens-specific information. .

Then, the driving pulse xi is calculated by the following formula: xi = image movement amount X ₀ / correction magnification KBLX or yi = image movement amount Y ₀ / correction magnification KBLY. Next, the data necessary for performing the above-described lens driving direction X: positive and negative driving speed V _xi , driving pulse X _i driving pulse X _i ′ direction Y: positive and negative driving speed V _yi , driving pulse Y driving pulse Y _i ′ Origin return is output to the lens side. Here, the origin return signal is set only when the lens is returned to the origin, and the lens returns the correction lens 32 to the origin only when this signal is present.

In the control on the lens side, the correction lens 32 is driven based on the input data as described above. When undetectable data is output, the same data as the immediately preceding data is output.

Next, control of the integration time of the CCD 51 will be described. No. 12A
The figure shows a circuit for controlling the integration time of the CCD 51, and includes an illuminance monitor SPD and a photometric circuit. The photometric circuit includes an integrating circuit and a reset circuit. SPD for illuminance monitor is CCD51
Is formed in the vicinity of the photographing area. The photocurrent output from the illuminance monitor SPD is integrated by the integration circuit. The output of the integration circuit is proportional to the amount of light input to the illuminance monitor during the integration period. The illuminance monitor and photometric circuit are used even when the subject is illuminated by an AC light source such as a fluorescent lamp.
In order to keep the output of the constant. When the subject under the illumination of the AC light source is imaged, if the integration time of the CCD 51 is kept constant, the readout output fluctuates every time. This will be described later. In order to stabilize the read output of the CCD 51, it is necessary to adjust the integration time according to the illuminance of the subject. In this embodiment, the integration of the photometric circuit is started simultaneously with the start of the integration of the CCD 51, and the exposure amount of the CCD 51 is monitored by the output of the integrating circuit.

 FIG. 12B is a modification of FIG. 12A.

Next, the first case of using the CCD 51 as a blur detection sensor
The operation of the integration time control circuit shown in FIGS. 2A and 12B will be described. The reset circuit is turned on, and the integration circuit is reset. The charge in the CCD storage section is cleared. When the integration of the CCD 51 is started, the reset circuit is turned off, and the photometric circuit starts the integration.

FIG. 13 is a diagram showing a temporal change in the output of the photometric circuit. The horizontal axis t indicates the integration time, and the vertical axis I indicates the magnitude of the output of the photometric circuit. When the subject is illuminated by the AC light source, the output of the photometric circuit rises in a curve as shown in the figure. By comparing the photometric output with the appropriate reference value I _0, the integrating circuit when the photometric output I becomes I ₀ is reset, the integral of the CCD51 is aborted. The output of the CCD 51 is read, and it is determined whether the exposure amount is appropriate. If the exposure amount is appropriate, the reference value I ₀ is used for the subsequent exposure. If the exposure amount is inappropriate, for example, the exposure amount is multiplied by k to make I ₀ × k a new reference value I _0, and subsequent exposure is performed.

Next, the operation of the integration time control circuit when the CCD 51 is used as an image sensor for an electronic finder will be described.
The output signal of the photometric circuit 31, a reference value I ₀ is set on the basis of a signal from the signal and film sensitivity setting means 23 from the exposure correction amount input unit 22 (for the contents of the main with reference to FIG. 14 This will be described in sequence step # 70 of the CPU).

The sequence of the camera including the above-described shake detection, correction, remote finder, and the like will be described based on the flowcharts of the main CPU and the shake correction control CPU.

First, the sequence of the main CPU 1 will be described. 14th
Referring to the figure, the main CPU is in a standby state in a loop of step # 5 (hereinafter, step is abbreviated). That is, # 5
Waiting for the switch S1 to be turned ON in the first stroke of the release button. Switch S1 is ON
, The AF completion flag AFEF and the signal are reset (# 10), and the necessary circuits such as the photometry circuit 31, the AF detection module 14, and the camera shake correction controller 18 are turned on (#
15). Next, the origin return signal of the correction lens 32 is transmitted to the photographing lens 3.
(# 20), and after the timer is reset, it is started (# 25), the lens data of the photographing lens 3 is input (# 30), and open metering is performed (# 35).

In # 40, it is determined whether the AF completion flag AFEF is 1 or not.
If it is 1, the program jumps to # 65. If it is not 1, the program goes to # 45. In # 45, AF detection is performed. In # 50, it is determined whether or not the camera is in focus as a result of the AF detection in # 45. If it is in focus, the program goes to # 55, and if not, it branches to # 60. In step # 60, after the photographing lens 3 is driven to the focus position, the program jumps to step # 45. At # 55, the AF completion flag AFEF is set to 1. In # 65, the AE calculation is performed based on the photometric value, the film sensitivity obtained in # 35, and the distance information obtained as a result of the AF in # 45. In # 70, the exposure amount of the CCD 51 is set.

Switch S2 of the second stroke of the shutter button at # 75
It is checked whether is turned on. Switch S2
If is ON, the program goes to # 105; if not, the program branches to # 80. In # 80, it is determined whether the switch S1 is ON. If the switch S1 is ON, the program jumps to # 25. If it is not ON, since the shutter button has not been pressed at all, it is checked by a timer at # 85 whether a predetermined time has elapsed. If the predetermined time has elapsed, the program jumps to the standby state of # 5 after turning off the power of the circuits such as the photometry circuit 3, the AF detection module 14, and the camera shake correction controller 18 (# 100). If the fixed time has not elapsed, the AF completion flag AFEF is set to 0 (# 90),
The program proceeds to # 80.

In step # 105, since the second stroke of the shutter button has been pressed, the release signal is set to the H level, and the control CPU is notified of that. After # 110, the aperture of the taking lens 3 is reduced to the aperture value obtained by the AE calculation of # 65 (# 110). The optical system is switched from the electronic viewfinder imaging optical system 41 to the blur detection optical system 40 (# 115), the blur detection signal is set to the H level, and the blur detection sequence of the control CPU is started (# 120). The AF mirror 7 is retracted (# 125), aperture metering is performed (# 130),
The shutter speed for which AE calculation was performed is corrected (# 13
Five).

In step # 140, the flow waits for the exposure permission signal from the control CPU to go high. When the exposure permission signal becomes H level, the shutter curtain 9 is run and exposure control is performed (# 145). When the exposure is completed, an origin return signal is output to the photographing lens 3 (# 150), the correction lens 32 is returned to the origin position, the blur detection signal is set to L level, and the control CPU is notified that the exposure is completed. (# 155).

The film is wound up (# 160), and it is determined whether the mode is the continuous shooting mode (# 165). If not in continuous shooting mode, the program branches to # 180 and if in continuous shooting mode, # 1
Go to 70 to determine whether the switch S2 is ON. If the switch S2 is OFF, the program in the continuous shooting mode but without continuous shooting branches to # 180. Switch S
If 2 is ON, continuous shooting is performed, so the blur detection signal is H
Leveled (# 175), the program jumps to # 130.

After # 180, the AF mirror 7 is returned to the detection position (# 18
0), the aperture of the photographing lens 3 is opened (# 185), the release signal is set to L level (# 190), and the control CPU
1 will be notified. The blur detection optical system 40 is switched to the electronic viewfinder imaging optical system 41 (# 200), and S2 is turned off.
(# 205), the program jumps to # 80 and prepares for the next shooting.

Next, the operation of the control CPU will be described with reference to FIG. Image stabilizer controller 18 at # 15 in Fig. 14
Is turned on, and the sequence is started. The flag and the output signal are reset (# B5), and integration is started after the integration of the CCD 51 is reset (# 10). When the integration is completed in # B15, the read data is stored in the image memory 64.
(# B20). The dumped data is sequentially read and D / A converted, and the video signal processing circuit 62
The image is displayed at 63. In # B25, the integration is started after the integration of the CCD 51 is reset, and the program is executed in # B1.
Jump to 5.

If the integration is not completed in # B15, the program branches to # 30. In # B30, the release signal from the main CPU is checked.
The program proceeds to 5, and if it is at the L level, the program branches to # B15. In # B35, the process waits until the shake detection signal from the main CPU goes to H level and the shake detection is started.

When the shake detection signal becomes H level, integration is started after the integration of the CCD 51 is reset. (# B40). At this time, the optical system has already been switched to the blur detection optical system by the main CPU. In # B45, the end of CCD51 integration is awaited.
After the CCD 51 integration is completed, the read data is stored in the reference memory 65.
And dumped to the reference memory 66 (# B50). After the integration of the CCD 51 is reset, the integration is started (# B55).

A contrast calculation is performed (# B60), and a block used for blur detection is selected (# B65). CCD
The completion of integration of 51 is awaited (# B70). After the integration is completed, the read data is dumped to the reference memory 66 (# B75), and the CCD 51
After the integration is reset, integration is started.

The correlation calculation (# B85) and the interpolation calculation (# B90) are performed, and the image blur amount is detected. The lens data of the taking lens 3 is read out (# B95), and the correction amount and direction of the correction lens 32 are calculated (# B100).

In # B105, it is determined whether or not the shake detection signal from the main CPU is at the L level. If the shake detection signal is at the L level, the shake detection ends, and the program branches to # B130. If the blur detection signal is not at the L level in # B105, the blur detection is continued, and the program proceeds to # B110. The exposure permission signal is set to the H level (# B110) to notify the main CPU that the exposure may be started, lens correction data is output to the photographing lens 3 (# B120), and the program jumps to # B70. I do.

In # B130, it is determined whether or not the release signal from the main CPU is at the L level. If it is at the L level, the program has jumped to # B10 since the shooting has been completed. If it is not L level, it is continuous shooting, so the program is # B135
To wait for the detection signal to go to the H level. When the detection signal becomes H level, the program jumps to # B40.

FIG. 16 shows another embodiment of the control CPU. Even after the release is started, the data is dumped to the image memory at # B247 and # B275, and the image information of the camera shake detection is displayed. In other words, the entire shooting area is LC just before the exposure
On the other hand, when the exposure starts, the optical system is switched and the camera shake detection area is displayed on the LCD 63 while the exposure is started.

[Effects of the Invention] As described above, according to the present invention, a subject image is captured by an area sensor by dividing a light beam for film photography, and the subject image is displayed on the display means before the photographing start instruction is used. Are displayed in sequence, and after the start instruction, the blur is detected by the blur detecting means and the display means displays the subject image. As a result, it is possible to provide a camera capable of confirming the display of the subject image before and after the photographing start instruction and confirming the presence / absence of blur during photographing.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main CPU which is a central part of a camera for detecting a blur with an electronic finder according to the present invention.
FIGS. 2A to 2D are views for explaining a mounting state of the electronic finder to the camera body, and FIG. 3A is a view showing an optical system of the camera for detecting a blur detected by the electronic finder according to the present invention, and FIG. FIG. 4A is a diagram showing details around a shake detection optical system driving means, FIGS. 4A to 4C are diagrams showing a screen of an electronic finder, and FIG. 5 is a diagram showing a modification of the optical system shown in FIG. 3A. 6A and 6B are diagrams showing a state of attachment of the electronic finder to the camera body in the embodiment shown in FIG. 5, and FIG. 7 is a block diagram of a camera shake detection and correction means. FIG. 8 is a schematic diagram of a light receiving unit of a CCD, FIG. 9 is a diagram for explaining a correlation value for obtaining an image blurring amount, and FIG. 10 is a diagram for explaining a method of interpolation calculation. FIG. 11 is a diagram for explaining a method of driving the correction lens, and FIG. FIG. 12B is a circuit diagram showing a circuit for controlling the integration time of the CCD, FIG. 13 is a diagram showing a time change of the output of the photometric circuit, and FIGS. 14 to 16 are electronic viewfinders according to the present invention. 6 is a flowchart for explaining operations of a main CPU and a control CPU of the shake detection camera. 1 is a main CPU, 2 is an SPD, 3 is a photographing lens, 4 is an aperture driving unit, 5 is a focus adjustment driving unit, 6 is a photographing lens circuit,
7 is an AF detection mirror, 31 is a photometry circuit, 32 is a correction lens, 40
Is a blur detection optical system, 41 is an electronic viewfinder imaging optical system, 42
Denotes optical system switching means. In the drawings, the same reference numerals indicate the same or corresponding parts.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Otsuka 2-3-113 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside the Osaka International Building Minolta Camera Co., Ltd. (56) References JP-A-54-55425 (JP, A) JP-A-1-194580 (JP, A) JP-A-64-78581 (JP, A) JP-A-61-215538 (JP, A) JP-A-2-239781 (JP, A) JP-A-59 -202417 (JP, A) JP-A-1-130126 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03B 5/00-5/08

Claims (1)

(57) [Claims] 1. A camera provided with a photographing optical system for introducing light from a subject and forming an image of the subject on a predetermined surface, the camera being provided in an optical path from the subject to the predetermined surface,
A semi-transmissive mirror that divides light from the subject; a two-dimensional area sensor that receives one of the lights from the subject divided by the semi-transmissive mirror and converts the light into an electric signal; A shake detection means for detecting a shake based on the output signal of the above; a display means for electrically displaying the subject image based on an output signal of the two-dimensional area sensor; a means for instructing a start of photographing; Prior to the start of photographing, the display unit sequentially displays the subject image based on the output signal repeatedly output from the area sensor, and after the start of photographing, the display of the two-dimensional area sensor is started. A system which causes the blur detecting means to perform blur detection based on an output signal during shooting and causes the display means to display the subject image. Camera, characterized in that a means.