JPH03192228A - Camera capable of blur detection and correction - Google Patents

Abstract

PURPOSE:To confirm focus on a screen and to attain blur detection which covers a low-brightness subject by making a finder part transparent only nearby a blur detection area and forming a diffusion surface at other parts. CONSTITUTION:An area (a) of the finder screen is a transparent blur detection area, an optical path to a sensor 44 is secured, and the quantity of light increases. An area (c) is a mat part, light is diffused, and an image is formed thereupon to detect the focus. An area (b) is the visual field range of an electronic finder, this part is also transparent, and the quantity of light to an image pickup optical system 41 increases. Then a blur detection optical system 40 forms an image of part (a) of the screen (c) nearby the center on the image pickup surface and the image is used by the blur detection sensor 44; when the image pickup optical system 41 is used, an image extending over nearly the entire area of the screen (c) is formed and used as an image for the finder. Consequently, the focus on the screen surface can be confirmed and the blur detection and correction which cover even low-brightness subjects are made possible.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a camera capable of detecting and correcting blur;
In particular, the present invention relates to a camera that is capable of automatic focusing and capable of detecting and correcting blur.

[Prior Art] In conventional cameras capable of autofocusing, the finder screen was a diffusing surface because the focus was confirmed on the screen. Furthermore, in general, conventional cameras with rlJ fT:: detect blur using a light beam that passes through a finder screen.

[Problem to be solved by the invention] If the finder screen of a conventional camera has a diffuser surface, the light beam that should be incident on the shake detection sensor that detects shake is diffused, reducing the illuminance on the sensor surface. There was a problem. Furthermore, there is a problem in that the roughness of the diffusion surface is imaged on the sensor, resulting in a decrease in detection accuracy. On the other hand, when the entire finder screen is made transparent, the illuminance on the shake detection sensor surface increases, but there is a problem that it becomes impossible to confirm the focus on the finder screen.

This invention was made in order to solve the above-mentioned problems, and by providing a camera that can detect and correct blurring, which allows you to check the focus on the screen and can also handle low-brightness subjects. be.

[Means for Solving the Problems] The camera according to the present invention which is capable of autofocus and capable of detecting and correcting blur has a shake detection system that detects shake of a subject using a finder screen and a beam of light that has passed through the finder screen. Only the vicinity of the optical path portion through which the light beam for detecting shake of the finder screen passes is transparent.

[Operation] In the camera according to the present invention, only the vicinity of the shake detection area of the finder portion is made transparent, and the other area is made into a diffusing surface. As a result, the amount of light directed to the shake detection sensor increases.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram showing the main part of the shake detection camera with electronic viewfinder according to the present invention.

Referring to Fig. 1, 5PD for photometry (Silicoll)
The signal from Photo (Photo) 2 is manually input to the photometric amount +831. The ΔN optical circuit 31 is 5PD2
It calculates the output of and outputs the calculation result to the main CPUI. The photographic lens is replaceable, and the aperture is driven and the focus is adjusted through an aperture drive means 4 and a focus adjustment drive means 5. The photographing lens circuit 6 stores the F value of the fixed H lens in the photographing lens 3, the focal length, and various parameters for blur correction. The photographing lens circuit 6 further includes an actuator for driving an optical system for blur extraction and its control circuit.

AF detection Miramuff, phase difference type AFF output module 14
A part of the luminous flux passing through the photographing lens 3 is guided to. The AF detection mirror is retracted by the AFF output mirror driving means 8 so as not to block light to the film during exposure of the Miramuff film. The shutter i9 of the focal brain shutter includes a leading curtain and a trailing curtain, and is driven by a shutter driving means 10. The switch S1 performs ONL, photometry, and AF operations at the first stroke of the shutter button. Switch S2 is turned on by the second stroke of the shutter button. The film winding means 15 winds and rewinds the film. Switches St' and S2' are shutter buttons installed on a remote finder, which will be described later, and have the same function as switches S1 and S2, respectively. Switch SC is a switch for operating continuous shooting mode.

The shake detection optical system 40 and the electronic finder imaging optical system 41 are driven by a shake detection optical system drive first stage 42,
This is an optical system for guiding light to a COD for shake detection, which will be described later. When performing shake detection, a shake detection optical system 40 is used, and when performing image display 7J< using the above-mentioned CCD, an electronic finder imaging optical system 41 is used. The main CPU is further connected to a camera shake correction controller 18 for detecting camera shake, which will be described later. The camera shake compensation 1E controller 18 performs an interaction 1d with the camera shake detection compensation IF means 11.

The main CPU further includes an exposure compensation amount input means 2 for performing exposure compensation for the exposure amount determined by the photometric value.
2 is connected to film sensitivity setting means 23 for setting film sensitivity.

Next, the electronic finder will be explained. Figure 2A ~ 2nd
Figure D is a diagram showing how the electric finder is used. '
Referring to Figure A2A, a removable and retractable electronic viewfinder 100 is provided on the top 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 the m2A diagram, it is used as a waist level finder. Figure 2B shows
FIG. 3 is a diagram showing a state in which the electronic finder 100 is pulled forward. You can see the finder image without looking into the finder eyepiece. Therefore, you can take pictures while checking the viewfinder image from the height of the camera held above your head. FIG. 2C shows a state in which the electronic finder 100 is pulled forward.

You can take self-timer shots while checking the viewfinder image. In this case, the image on the finder image display LCD 63 is upside down compared to the normal case. FIG. 2D is a diagram showing a state in which the electronic viewfinder 100 is removed from the camera body 12. Using the electronic viewfinder extension cord 102, press the release button 1 while observing the finder image on the LCD 63.
01 allows remote photography.

The image tmtJ on the LCD 63 is captured by the CCD imaging unit 51 of the shake detection sensor 44, which will be explained later with reference to FIG. The exposure time of the CCD at this time is determined based on the exposure of the camera. Therefore, the LCD 6 displays an image with a density similar to that of the finished photograph. When shooting with auto exposure, set exposure compensation (if necessary,
The exposure correction amount manual means 22 may be adjusted so that the part to which the exposure is mainly desired can be observed with good gradation while viewing the LCD 63. When determining the exposure when photographing by manual exposure, the aperture and shutter speed may be adjusted so that the part to be exposed can be observed with good gradation while looking at the LCD 63. Further, even if you want to intentionally overexpose or underexpose, if you decide on the exposure while observing the LCD 63, you will be able to obtain a photograph with the desired exposure.

FIG. 3A is a diagram showing an optical system of a shake detection camera with an electronic finder according to the present invention. Referring to FIG. 3A, the photographing lens 3 includes a shake correction lens 32 and a shake correction lens driving device 33 for moving the shake correction lens 32. Note that the details of the correction lens driving device 33 are well known, so a description thereof will be omitted. camera body 12
A mirror mirror 34 is fixed inside, and part of the light beam passing through the photographic lens 3 is reflected toward the finder optical system, and the rest is transmitted toward the shutter curtain 35. A part of the light beam transmitted through the pellicle mirror 34 is guided toward the phase difference AF detection module 36 by the AF9 output mirror 7. During film exposure, the AF detection mirror 7 performs AF to a position that does not block the light flux reaching the film during exposure.
It is evacuated by the detection mirror drive f stage 8 (not shown).

The light beam reflected by the pellicle mirror '34 passes through the condenser lens 37 and enters the pentaprism 38.

There is a photometric 5PD on the eyepiece lens 39 side of the pentaprism 38.
2 is provided. One element 38a of the pentaprism 38
is a half mirror, and extracts a part of the incident light flux to the outside of the pentaprism 38. The extracted light beam passes through a blur detection optical system 40, is reflected by a reflecting mirror 4, and reaches a blur detection sensor 44. The blur detection optical system 40 and the electronic viewfinder imaging optical system 41 are driven by an optical detection optical system driving means 42, and are selectively moved into and out of the optical path. The shake detection optical system 40 and the electronic finder imaging optical system 41 each re-image the image on the finder focal plane 45 onto the shake detection sensor 44. The shake detection sensor 44 is a CCD area sensor. In addition, pentaprism 38
In addition to the glass block type, it may also be a hollow pentamirror with an air layer inside.

As described above, in this invention, the pellicle mirror 34
Since the light from the photographic subject is transmitted to the area sensor 44 which serves as a shake detection sensor, blur detection is performed using an image detection method in a TTL camera. moreover,
A pentaprism 38 is placed in the optical path up to the shake detection sensor 44.
, there is no need to provide a separate optical path to the shake detection sensor 44.

FIG. 3B is a diagram showing details around the blur detection optical system driving means 42. Referring to FIG. 3B, a lens holder 200.201 having a lens 40a of a blur detection optical system 40 and a lens 41a of an electronic viewfinder imaging optical system 41 fixed to a rotation shaft 205 is fixed to a rotation shaft 205, and a motor 210 is connected to the rotation shaft 205 through a gear.
is connected to. The shaft of the motor 210 is interlocked with the disk-shaped chipper 202 via a gear, and the encoder spring 202
The rotation of is read by the photocoupler 203. As the encoder spring 202 rotates, the photocoupler 203
An on-off signal is generated each time the light between the arms of the robot is interrupted. The controller 204 counts this pulse signal. As a result, the amount of rotation of the rotating shaft is monitored. Each lens 40a% 41a of the blur detection optical system 40.41 is rotated by turning on or off power to the motor 210 according to the monitored signal.

In this manner, the blur detection optical system driving means 42 switches the optical path between the blur detection 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.

FIGS. 4A to 4C are diagrams showing finder screens. 4A and 4B is a transparent blur detection area, and because of this area, an optical path to the sensor 44 is secured and the amount of light to the sensor 44 is increased. The area indicated by C is the matte portion of the finder screen, on which light is scattered, an image is focused on it, and the focus is detected in the conventional manner.

The area indicated by a is also used for displaying the finder display frame of the shake detection area. b in FIG. 4A is the field of view range of the electronic finder, and this part is also transparent, so that the amount of light to the imaging optical system 41 for the electronic finder increases. FIG. 4C is a diagram showing a case where the entire surface of the finder screen is transparent.

A portion a near the center of the finder screen C is imaged on the imaging surface by the blur detection optical system 40.

This image is used by the shake detection sensor 44.

Furthermore, when the electronic finder imaging optical system 41 is used,
Almost the entire area of the finder screen C is imaged on the imaging surface, and the image is used as an image for the electronic finder.

Note that, referring to FIG. 3A, the photographing lens 3 is attached to the camera body 12 via a lens mount portion 46, and is replaceable.

Note that if a normal lens without a camera shake correction lens is attached to the camera body 12, a warning will be displayed on the finder screen when shake is detected. A warning about camera shake may be displayed on the electronic viewfinder with the words "Be careful of camera shake".

FIG. 5 shows another embodiment of the optical system according to the invention. In this case, the pentaprism 38 is omitted compared to the optical system shown in FIG. 3A.

Since there is no pentaprism 38, finder screen, or condenser lens 37, the cost can be reduced accordingly, and it is also lighter and more compact. Shake detection sensor 44'
A reimaging lens 45' is provided in front of the sensor.

The small-area relay lens 40' and the large-area relay lens 41' are used in a switched manner, thereby switching the light flux guided to the area sensor 44'. The optical system according to this embodiment is provided with a reflecting mirror 43' and an optical system drive actuator 42'.

FIGS. T86A and 6B are diagrams showing how the finder screen is used when the optical system according to another embodiment of the 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, the electronic finder 63 is removable.

Next, the contents of the camera shake detection and correction means 11 will be explained with reference to FIG. The camera shake detection sensor 44 includes a CCD imaging section 51, an output amplifier 52 for amplifying the CCD output, a fish skin monitor 53 for controlling the integration time of the CCD, and a lung 1 circuit 54. A clock generator 55 detects the output of the photometric circuit 54 and sets the integration time of the CCD and the gain of the output amplifier. In addition, the clock generator 5
5 is a COD drive clock, A/D converter 61, D
A clock is also generated for the /A converter 58, the sensitivity variation correction memory 59, and the dark output correction memory 60. The output of the shake detection sensor 44 is input to the A/D converter 61 through a differential amplifier 56 and a gain control amplifier 57. The dark output correction memory 60 and the sensitivity variation correction memory 59 respectively store data for correcting CCD sensitivity variations and dark output. Dark output correction memory 60 outputs data to D/A converter 58. The output signal of the D/A conversion is input to the differential input of the differential amplifier 56. As a result, the dark output of the CCD 51 is corrected. The gain control amplifier 57 is an amplifier whose amplification degree is controlled by a digital signal. The gain control amplifier 57 is controlled by the sensitivity variation correction data stored in the sensitivity variation correction memory 59, and
Correct sensitivity variations in CD output.

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

The arithmetic unit 68 includes a subtraction circuit 69, an absolute λ/I chain circuit 70,
It includes an adder circuit 71 and a register 72. Reference section memory 6
5 and the data in the reference section memory 66 are given as inputs.

The calculation results from the calculator 68 are stored in a correlation result memory 73, a vertical contrast memory 74, or a horizontal contrast memory 75 depending on the type of calculation. These memories are connected to the control CPL 176,
It can be accessed from the control CPU 76. Control CPU 76 also controls address generator 67 and clock generator 55. The data in the image memory 64 is D/A converted by a D/A converter 77 and input to the video signal processing circuit 62 . The switch SRV is a switch that is turned on when the LCD 63, which is an electronic viewfinder, is pulled forward.

When this switch is turned on, the video signal processing circuit 62 displays the video on the LCD 63 with the video upside down.

Next, a method of detecting blur and calculation of the amount of blur will be described.

First, the shake detection sequence will be explained. In this invention, a subject image is detected in a two-dimensional manner using an area sensor 44 that can detect two-dimensional image data. Image blur is detected by detecting the shift of the subject image over time using the area sensor 44.

The CCD 51 is an lxJ area sensor.

, AA sub-division memory 65 and reference section memory 66, respectively! The memory has a capacity of XJ words, and the correlation result memory 73 has a capacity of HXH words. CCD51
Consider dividing the light-receiving surface into MXN blocks. Each block is composed of adjacent KXL pixels. The vertical contrast memory 74 and the horizontal contrast memory 75 are each MX
The memory has a capacity of N words. The procedure for detecting blur will be explained below.
-8, L-8, M-8, N-6, H-5.

It is assumed that the resolution of the A/D converter 61 is 8 bits, the register 72 is 14 bits, and one word of the correlation result memory 73, vertical contrast memory 74, and horizontal contrast memory 75 is each represented by 14 bits.

FIG. 8 is a schematic diagram of a portion of the light receiving section of the CCD 51. One grid of small squares represents a unit pixel. In the figure, the pixel on the left side is assumed to be pixel (1, 1), and the pixel on the upper right side is assumed to be pixel (68, 52). The light receiving section of the CCD 51 is divided into blocks each consisting of 8 pixels x 8 pixels, except for two pixels on the outer periphery of the light receiving section. The parts surrounded by thick lines in the figure correspond to each block. Block the block on the left (L 1),
Let the upper right block be block (8, 6).

The shake detection sequence is large. (1) Contrast calculation and block selection (2) +n Kanshi 1 arithmetic (3) Interpolation = 1 calculation It is divided into three parts.

Contrast calculation is a calculation performed for block selection. Among the various parts of the object imaged on the light receiving section of the CCD 51, some parts are suitable for blur detection, while others are not. In this embodiment, the contrast of the object is calculated in order to select a portion suitable for blur detection. The contrast of the subject is calculated for each block, and a total of 8 blocks, 4 blocks with high contrast in the vertical direction and 4 blocks with high contrast in the horizontal direction, are taken once a month.
Is it possible to detect blur? i will be told.

(1) Description of contrast calculation and block selection First, the output of the CCD 51 is stored in both the reference part memory 65 and the taillight part memory 66. Using this data, the contrast in the vertical direction and the contrast in the bA/r direction of each block is calculated. The calculation is block (1, 1)
, (2,1), ... (7°6), (8,6) horizontal contrast, block (1,1), (2,1)%
...The vertical contrast is performed in the order of (7, 6) and (8°6).

The output of pixel (i, j) of CCD 51 is A(i.

j), an address is sent from the address generator 67 so that the horizontal contrast and the vertical contrast of the block (k, (1,) are given.The data subtracted by the subtraction circuit 69 is an absolute value. The absolute value is taken in the circuit 70 and added to the register 7 in the adder circuit 71.
2 and stored in the register 72. Next, the address to be i-it1 is sent from the address generator 67, and the same =1m is performed. In this way, +2 to 1-8(k-1)+2 to 8, j-8(fL-1
) When processing is performed in the range of +3 to 8N+2, register 7
2, the procedure for executing this calculation formula on the hardware shown in FIG. 7 will be explained below. The contents of the reference section memory 65 corresponding to the output of image 4 (i, j) of the CCD 51 are R(1, J), and the contents of the reference section memory 66 are S(i.

j). First, clear the register 72 >JJ. Next, Rci,j) is input to the -h° input of the subtractor 69, and S (it1.j)'! is input to the other input. However, i −8(
k-1)+2 and j-8(gon-1)+2) are stored.

The reference part memory 65 and the reference part memory 66 store the same contents A(K, j), and Aci, j) R(
i, j) -3ci, j), the contents of the register 72 and the contents of the horizontal contrast tough 2 are transferred to and stored in the horizontal contrast memory 75 corresponding to that block.

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

Vertical contrast is then calculated. The horizontal contrast is 31. First, the register 72 is cleared, as in the case of calculation. Next, R(i, j)% is input to one input of the subtraction circuit 69, and S(i, j→1) is input to the other input (however, i-8(k-1)+3, j-8(11)+2, do)
An address is sent from the address generator 67 so that the address is given.

The data subtracted by the subtraction circuit 69 has its absolute value taken 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. Then i=i+1
The address to be obtained is sent from the address generator 67, and a similar calculation is performed. In this way, i-8(
k-1) +2 to +3 to 8, j -8 (IL-1) +2
Processing is performed in the range of ~8+2. As a result, the following is stored in the register 721; Here A ('+ J) - R(
itj) -8(・it J), so the contents of the register 72 are stored in the vertical contrast memory 74.
is transferred to the location corresponding to that block and stored.

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

The control CPU selects a block with the highest contrast from among the contrasts in the vertical and horizontal directions of each block obtained as described above. Next, choose a contrast direction from the remaining blocks that is different from the contrast direction you selected first (for example, if the first choice was vertical, then horizontal)
Select the block with the highest contrast. Thereafter, eight blocks (vertical, four gantry blocks each) are selected in descending order of contrast while changing the direction of contrast. The selected blocks are 81 to B8.

(2) Description of Correlation Calculation As for the contents of the reference section memory 65, the data on which the contrast has been calculated is left as is as reference image data. New data is successively read from the CCD 51, and each time new data is written into the reference section memory 66 as a reference image. Every 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 determined by the correlation calculation and interpolation calculation described above.

Block Bk (k-1, 2,...8) correlation ((
, ■+m-L-1+0°, 1.2 > (1i, Ji represents the youngest pixel number in block Bk) Considering the case of fl-m -0, it becomes. This value is the sum of the absolute value of the difference between the data of the same pixel in the standard image and the reference image for one block. Q
Considering cases other than m m m O, Ck
(L m) is the absolute value of the difference between the data of pixel (i, j) of the reference image and the data of pixel * (i + (1, j + m)) of the reference image - 1 block is added. 8 blocks. Let the correlation value C (story, m) - Σ Ck (garden, m) Ki -1 (Q! - m - -2, -1, 0, 1, 2) be obtained by adding the correlation value of .

The reference section memory 65 is connected to the -Jj input of the subtraction circuit 69, and the reference section memory 66 is connected to the other input. Therefore, after clearing the register 72, the subtraction circuit 6
R (i, j) to one input of 9, and the other input S (i+
Q, j+m) is input, and the address generator 67 outputs an address determined by the control CPU so that data in a predetermined range of iSj is processed. Then, C(L m) is obtained in the register 72. This is transferred to a predetermined address in the correlation result memory 73 and stored. By repeating the above process by changing the chain of 91-unit 1, C(11, m) :(see, lT
l--2, -1, 0, 1, 2) are all found.

(3) Explanation of interpolation calculation When the calculated correlation ViC (1, m) is arranged on the horizontal axis and n is arranged on the vertical axis, it becomes an array like a number.

e(-2,1) C(-!,1) C(0,1)
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(-t,-2) c(a,-
x) C(1,-2) C(2,-2) If there is no deviation between the standard image and the reference image, C(L), O
) becomes 0, and the further outside the array, the larger the value. Also, the reference image is 1o to the right of the standard image.
Assuming that the Fi element is shifted upward by mO pixels, C(lLo
r mO) becomes O, and the further away from it, the larger the value. However, the image shift is not limited to the integer number Δ of the pixel.

Furthermore, since the speed of image blur is not constant, the blur of the image due to image blur may differ between the standard image and the reference image. The distribution of the correlation values CNL, m) in this case can be expressed as equal straight lines as shown in Fig. 9. Referring to Figure 9,
Although values are actually obtained only on the lattice points in the figure, equal lines are drawn assuming values between the lattices. The center of the isoline has the smallest value. The center of the isoline is the coordinate (X
O.

yo), and the reference image is XOs horizontally and y vertically with respect to the reference image. It is thought that there is a deviation. H1 flash:
Since only the values on the grid points are obtained in one calculation,
The MP points must be determined by interpolation using grid point data. The magnification of the blur detection optical system 40, the pixel size of the CCD 51, and the integration time are set so that the MP point satisfies -1-5<xQsyO<1.5, assuming the actual magnitude of the blur.

The interpolation calculation after the completion of the correlation=1 calculation will be specifically explained. The calculation of =1 in the horizontal direction will be explained. First, C (gong, r
Find the minimum value CN1o,mo) of r+).

The value of Qo and Ctllo−+, me ) and C(i
oft.

The cases are divided into the cases shown in (a) to (h) in FIG. 10 depending on the magnitude relationship with mo).

(a) To the place of conditions It is determined that 0≦xg<l.

Point (-1,C(-1,mo)) and point (0,C(0,
m6)) and the point (1, C(1, m6
) ) and the straight line (
Let the coordinates of the intersection with i i) be XQ.

lo −−C(28ms)+2・C(1, go)−C(
0, meeting. )C(Ov))-C(-1,5o)-C(2,
m. )”C(1,56)(b) In the case of the condition, it is determined that 1 x x0.

Points (-2,C(-2,rrmo)) and (-1,C
(-1,lTl0) ) and the point (0
゜C(0,mo) ) and the point (1,'C(1,mo
))) Let the garden coordinates of the intersection with the straight line (11) be XQ.

IQ - C(0,1o)-2◆C(-1,lo)+C(-2,1
a) C(-1,@,)-C(-2, Sono.)-C(1,@
, ) 10 (mouth, -0) (c) In the case of the condition, it is determined that 0<xo<1.

The following is the same as in case (a), 1,, = -C(2,s)''2C(1,5o)-
C(O mountain)C(0,syu) -C(-1,s,)-C
(2, m.) + C (1, ■.) (d) In the case of the condition, it is determined that 1≦XO<2.

Point (0,C(0,mo)), (1,C(1,mo)
) and a straight line (ii) that passes through (2,0(2,m6)) and whose slope is opposite to that of the straight line (i). Let XQ be the garden coordinates of the intersection.

,. ,,-3・C(0,-o)+2・
C(1,so)+C(2,IQ)2 Fist(C(
1,go)-C(0,10))(e) In the case of condition-1≦x(1<Q).

The following is the same as in (b), xo --〇(0,5o)-2 fistC(-1,10)+C
(-2,141)C(-11o)-C(-2,5o)-
In the case of the condition C(1, so)+C(0, Maro.)(f), it is determined that -2<x6<-1.

Point (-1,C(-1,mo)) and point (0,C(10
, no )) and the point (-2°C(-
2, mO) ), and the 9 coordinates of the intersection of the straight line (i i) with the slope and the straight line (i) with the opposite sign are set as x6.

2 ・(C(0,so) -C(-1,s
o)) In the case of conditions (g) and (h), it is determined that the amount of shake cannot be detected as a shake exceeding the assumed maximum shake has occurred.

Although the procedure for determining XQ has been described above, yo can also be determined in the same manner.

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 image blur will be considered. In FIG. 11, the horizontal axis t represents time, and the vertical axis X represents the position of the image, 1-, . 1-2, t-1
,... represent the integration start time of the CCD 51, i-3
, L2, t-1, . . . represent the integration completion time. The integration time TI is expressed as T1,mt,-t.

If the subject is illuminated with an AC light source, CCD51
The integral time is expressed so that the exposure amount is constant. Therefore, the integration time is not constant. Integration start time 1-
,． 1-, , e-1s"' are equal intervals Ts. A solid curve 301 shows the locus of the image on the CCD 51 when there is image blurring. When blurring is not corrected by the correction lens 32, , the image moves on this curve. Note that the blur correction starts from t-"tQ, so the curve 301 moves on the point (
tg, O). A polygonal line 302 is the 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 correction. Points P-2, P-1, P Os...
・ is the integration period 1-, ~1-. 1-2~t-2, t-
, ~ represents the average position of the image at -7...

The CCD data integrated between t1 and tl' is t1◆
The image is read out between 1 and t, and calculation processing is performed to obtain the image position P. From ``++2'', the correction lens 32 is driven by the obtained data.

In addition, in the following explanation, P-2, p-,, P Q s
...,X4,X2,X3,...,X,',X2,
X, ..., xo Sx, , x3 ...
is the name of a point and is also used as the value of the X coordinate of that point.

In order to correct from time t-tQ, from tQ to t,
It is necessary to find the speed of the blur between the two.

Find the speed of blur from the recent changes in the image position of the two points, and
Predict that the speed of the blur between ~t7 is the same as that.11?1
do. The latest image position known at the time of t-tQ is P
, is. The time from P-2 to P-1 is TS-(T
x-, -TI-, )/2, so t.

1'71?1 value VxO of the velocity of the blur of ~t. Therefore, between to and [, the correction optical system is Vx(l
is driven at a speed of

Next, consider the case of time tmt. At this time, since the correction lens 32 was driven by Vxo, it is moved to the position of Xo'. At this point, the position of po is known, so t
The predicted value vxl of the blur speed of H-12 is calculated as follows.

Since the velocity VXj is obtained based on recent image position data, it is considered to be more accurate than VXO as a predicted value of the blur velocity during i(1''=*H. The error ERX is calculated as follows.

ERx + ” (Vx O-Vx +) ” T
The position of the image at i m i from S these chains, X, is measured as follows.

X, -VxO-TS-C; -ERx.

” (Vxo c (Vxo vx+)) ・T
SG is called a prediction coefficient, and FIG. 11 shows the case of prediction coefficient G-2. Here, the correction lens 32
needs to be driven to the newly predicted point X7,
Driving requires a time of t, to t,/. During that time, it is predicted that the image will move to the position of X,', so the correction lens 32 will move to the position of
-t, ), and between t, l and t2, ■8. is driven at a speed of

Next, consider the case of time t"tz. At this time, the correction lens has been moved to the positions represented by X, -X, +vx, -TS. At this point, the predicted value of the velocity
2 can be calculated as 1 as follows.

VX2 is 1. The predicted value of the blur speed between -12 is v
It is considered that the accuracy is higher than xl. Therefore, the preliminary 11 error E
Calculate RX2 as follows.

E RX 2- (Vx + -Vx 2) T
S From these values, the image position X2 at 1-12 is calculated as follows.

X2-X'-C;-ERx.

=X+ + (Vx) - to (Vx
+ -VX 2 )) TS Here, the correction lens 32 needs to be driven to the newly preset position X2, but the driving requires a time of t2 to 12/. During that time, the image moves to the position of X2, which can be predetermined by 3-1, so the correction lens 32 is driven to the position of X2 - X2 + V, be done.

Next, time 1-1. Consider the case of At this time, the correction lens X2'' is at a position represented by X2''X2+Vx2-'rs. At this point, the position of P2 is known, so the deviation velocity between t and t4 (however, [-t
, ~tmt,' are ignored. )vx, is t2~t
Since it is considered to be more accurate than vx□ as a predicted value of the blur speed between 8 and 8, the predicted ffi2mER3 is obtained as follows.

ER3-(Vx 2-VX s ) ” TS From these values, the image position X at 1-1. is X, = Xz −
G Threat ERx a ”X2 + (VX 2-G (Vx 2-VX 3)
It can be predicted that it will be 1TS. Here, the correction lens 32 is newly prefilled.
The image needs to be driven to the position
Since it can be predicted that the correction lens 32 will move to the position
is driven to the position of X,'-x,+vx3* (t31-t3), and is driven at a speed of VX3 between t3' and t1.

Hereinafter, in the same way, X4, VX 4, Xl, VX3
, . . . are determined, and the correction optical system is driven.

Note that in this example, the prediction coefficient G is constant.

However, depending on the situation of shake detection, the value of G may be changed during the correction sequence. If the prediction error ER does not become smaller even after several times of blur correction,
Or, if the sign of the prediction error ER, is not reversed,
The prediction coefficient G may be increased. Also, the prediction error ER,
If the sign of G cannot withstand repeated inversions, the value of G may be reduced.

Referring to FIG. 11, the time TR from time t6 to tz
is the camera's exposure time. As can be seen from FIG. 11, the sequence for performing camera shake correction is repeated many times within this photographing exposure time TR. Therefore, 1
Correction is not performed only once or twice, but at least several times. Therefore, the time required for actual camera shake amount calculation and correction must be performed within a reasonably short period of time. In addition, the integral time of the sensor for detecting camera shake is T I 3 , T I 2 , ・” T 16 ・”
T I n also needs to be short. TI while the photographing exposure time TR is on the order of several tens of mg to 1000 msec. is about several ms. If this relationship is not maintained, the effect of image stabilization will not be apparent.

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

Next, the interface between the interchangeable lens 3 and the camera body 12 will be explained. From the interchangeable lens 3, correction magnifications KBLX, KBLY (ff1 corresponding to each focal length when zooming is performed): (image movement 1i1 on the film surface) / (drive pulse) are input as lens-specific information. .

And drive pulse xi - image movement EIXo/correction magnification KB
It is determined by LX or yi-image movement mYo/correction magnification KBLY. Next, the data required to drive the lens described above: ■ Direction X: positive, negative ■ Drive speed ■ xl ■ Drive pulse Xl ■ Drive pulse X.

■Direction Y: Positive, Negative ■Drive speed Vyl ■Drive pulse Y ■Drive pulse Y.

■Return to origin information is output to the lens side. Here, the origin return signal (2) is set only when the lens is returned to the origin, and the lens side returns the correction lens 32 to the origin only when this signal is present.

Note that $ill on the lens side drives the correction lens 32 as described above based on the input data.

Furthermore, when undetectable data is output, the same data as the previous data is output.

Next, control of the integration time of the CCD 51 will be explained. FIG. 12A shows a circuit for controlling the integration time of the CCD 51, and includes an SPD for illuminance monitoring and a photometry circuit. The photometric circuit includes an integrating circuit and a reset circuit. The illuminance monitor SPD is formed near the imaging area of the CCD 51. The photocurrent that is the output of the illuminance monitor SPD is integrated by an integrating circuit. The output of the integrating circuit is proportional to the amount of light incident on the illuminance monitor during the integration period. The purpose of using the illuminance monitor and photometry circuit is to keep the output of the CCD 51 constant even when the subject is illuminated with an AC light source such as a fluorescent light. This is because when capturing an image of a subject under illumination with an AC light source, if the integration time of the CCD 51 is kept constant, the readout output will vary each time. This will be discussed later. In order to stabilize the readout output of the CCD 51, it is necessary to adjust the integration time by 2J in accordance with the illuminance of the subject. In this embodiment, the photometric circuit starts integrating at the same time as the CCD 51 starts integrating, and the output of the integrating circuit
The exposure amount of D51 is monitored.

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

Next, the operation of the integral time control circuit shown in FIGS. 12A and 12B when the CCD 51 is used as a shake detection sensor will be described. The reset circuit is turned on and the refinement circuit is reset. The charge in the storage section of the CCD is cleared. When the CCD 51 starts integrating, the reset circuit is turned off and the photometry circuit starts integrating.

FIG. 13 is a diagram showing temporal changes in the output of the photometric circuit. The horizontal axis t represents the integration time, and the vertical axis I represents the magnitude of the output of the JIJ optical circuit. If the subject is illuminated by an AC light source, il? The output of one optical circuit increases in a curved line as shown in the figure. Set the photometric output to an appropriate reference value!
, when the photometric output I reaches io, the integration circuit is reset and the integration of the CCD 51 is discontinued. C
The output of the CD 51 is read and it is determined whether the exposure amount is appropriate. If the exposure amount is appropriate, the reference 1i11o is used for subsequent exposures. If the exposure amount is inappropriate, for example, the exposure amount is multiplied by 1o
k is set as a new reference V11o, and subsequent exposures are 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. Output signal of δ-1 optical circuit 31, exposure correction amount manual means 2
The reference value No. is set based on the signal from the film sensitivity setting means 23 and the signal from the film sensitivity setting means 23 (this content will be explained in sequence step #70 of the main CPU with reference to FIG. 14).

The camera sequence including the blur detection, correction, remote finder, etc. described above will be explained based on the flowchart of the main CPU and the control CPU of the blur correction "E".

First, the main CPUI sequence will be explained. Referring to FIG. 14, the main CPU is in a standby state in the loop of step #5 (hereinafter the step is abbreviated). That is, the loop #5 waits for the switch S1 to be turned on by the first stroke of the release button. When the switch S1 is turned ON, the AF completion flag AFEF and the signal are reset (#10), and the υ1 optical circuit 31, A
Power is turned on to necessary circuits such as the F exposure module 14 and the image stabilization controller 18 (#15).

Next, the origin return signal of the correction lens 32 is output to the photographic lens 3 (#20), the timer is reset, and then started (#25), the lens data of the photographic lens 3 is input manually (#30), and the camera is opened. Photometry is performed (#35)
.

In #40, it is determined whether the AF completion flag AFEF is 1, and if it is 1, the program jumps to #65, and the AF completion flag AFEF is set to 1.
Otherwise, the program proceeds to #45. AF in #45
Detection is performed. In #50, it is determined whether or not the subject is in focus as a result of the AF detection in #45. If it is in focus, the program goes to #55, if it is not in focus, it goes to #60.
Branch to. After the photographing lens 3 is driven to the focus position in #60, the program jumps to #45.

At #55, the AF completion flag AFEF is set to 1.

In #65, AE calculation is performed based on the 1111 light value obtained in #35, the film sensitivity, and the distance information obtained as a result of AF in #45. In #70, the exposure amount of the CCD 51 is set.

At #75, switch S for the second stroke of the shutter button
It is checked whether or not 2 is turned on. If switch S2 is ON, the program goes to #105,
If not ON, branch to #80. In #80, it is determined whether the switch S1 is ON. If switch S1 is ON, the program jumps to #25. If it is not ON, the shutter button has not been pressed at all, so #8
In step 5, check the timer to see if a certain amount of time has elapsed. If a certain period of time has passed, 11$3 Optical circuit 3, AF
After turning off the power to the circuits such as the detection module 14 and the camera shake correction controller 18 (#100), the program jumps to the standby state in #5.

If a certain period of time does not pass, the AF completion flag AFEF becomes 0.
is set (#90), and the program proceeds to #80.

At #105, since the second stroke of the shutter button has been pressed, the release signal is set to H level, and the control CPU is notified of this.

After #110, the aperture of the photographic lens 3 is stopped down to the aperture value determined by the AE calculation in #65 (#110).

Image pickup optical system 41 for electronic finder Shake detection optical system 4
The optical system is switched to 0 (#115), the shake detection signal is set to H level, and the shake detection sequence of the control cPυ is started (#120). The AF mirror 7 is retracted (#125), and the focusing 111 light is performed (#125).
130), the shutter speed at which the AE calculation was performed is corrected (Trial 135).

At #140, the CPU waits until the exposure permission signal from the control CPU becomes H level. When the exposure permission signal becomes H level, the shutter 'Fi9 is operated and exposure control is performed (#145). When the exposure is completed, a return-to-origin signal is output to the photographing lens 3 (#150), and the correction lens 32
is returned to the origin position, the shake detection signal is set to L level, and the control cPU is notified that the exposure has ended (#155).

The film is advanced (#160), and it is determined whether continuous shooting mode is selected (#165). If it is not the quick-shot mode, the program branches to #180, and if it is the quick-shot mode, the program goes to #17o, where it is determined whether the switch S2 is ON. Here, if the switch S2 is OFF, the program branches to #18o in continuous shooting mode but not continuous shooting.

If the switch S2 is ON, rapid shooting is performed, so the blur detection signal is set to H level (#175) and the program jumps to #130.

After #180, the AF mirror 7 is returned to the detection position (1
180), the aperture of the photographic lens 3 is opened (#185)
), the release signal is set to L level (#190), and the control CPUI is notified of this. The camera shake detection optical system 40 is switched to the electronic viewfinder imaging optical system 41 (#200), and waits for S2 to turn OFF (#20).
5) The program jumps to #80 and prepares for the next shooting.

Next, the operation of the control CPU will be explained with reference to FIG. At #15 in FIG. 14, the power to the 14-shake blur correction controller 18 is turned on, and the sequence is started. The flag and output signal are reset (#B5),
After the integration of the CCD 51 is reset, integration is started (#B10). If the integration is finished at #B15,
The read data is dumped to the image memory 64 (#B
20).

The dumped data is sequentially read out and D/A converted,
An image is displayed on the LCD 63 by the video signal processing circuit 62. At #B25, after the integration of the CCD 51 is reset, integration is started, and the program jumps to #B15.

If the integration is not completed at #B15, the program branches to #B30. At #B30, the release signal from the main CPU is checked, and if it is at H level, the program advances to #B35-\, and if it is at L level, the program branches to #B15.

At #B35, it waits until the shake detection signal from the main CPtJ becomes H level and shake detection is started.

When the shake detection signal becomes H level, integration is started after 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. At #B45, the completion of the integration of CCD'51 is awaited. After the CCD 51 completes the integration, the read data is dumped into the standard memory 65 and reference memory 66 (#B'30). After the integration of the CCD 51 is reset, integration is started (#B 55).

Contrast calculation is performed (#B60), and a block to be used for blur detection is selected (#B6
5). Waiting for CCD51 to complete integration (#870)
. After completing the integration, dump the read data to the reference memory 66 (#B75), and after resetting the integration of the CCD 51,
Integration begins.

A correlation calculation (#B85) and an interpolation calculation (#B90) are performed to detect the amount of image blur. Read the lens data of the photographing lens 3 (#895), correct the correction lens 32,
The amount and direction are fipped (#B100).

In #8105, it is determined whether or not the shake detection signal from the main CPU is at L level. If it is at L level, shake detection is terminated, and the program branches to #B130. #B10
If the shake detection signal is not at L level in step 5, shake detection continues, and the program advances to #B110. The exposure permission signal is set to H level (#8110), notifying the main CPU that exposure may be started, lens correction data is output to the photographing lens 3 (#B120), and the program jumps to #870. .

At #B130, the release signal from the main CPU is L.
determine whether the level is If the level is L, the program jumps to #B10 because the shooting has ended. If it is not the L level, continuous shooting is being performed, so the program advances to #B135 and waits for the detection signal to become the H level. If the detection signal goes to H level, the program goes to #B.
40B40 Hedge Jump FIG. 16 is another embodiment of the control CPU. Even after the release starts, #B247 and #B275
The data is dumped to the image memory, and image information for camera shake detection is displayed. In other words, the entire photographic area is displayed on the LCD 63 until just before exposure, but once exposure begins, the optical system is switched and the camera shake detection area is displayed on the LCD.
This is done on D63.

[Effects of the Invention] As described above, according to the present invention, autofocus is zero.
In a camera capable of detecting and compensating for blur, only the vicinity of the blur detection area in the viewfinder is made transparent, and the other parts are made into a diffusive surface. Therefore, the amount of light directed to the shake detection sensor increases. As a result, it is possible to provide a camera that can confirm focus on the screen, can handle low-luminance objects, and is capable of detecting and correcting blur.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a main CPU that forms the central part of a shake detection camera with an electronic viewfinder according to the present invention, and FIGS. 2A to 2D are diagrams for explaining how the electronic viewfinder is attached to the camera body. FIG. 3A is a diagram showing the optical system of the shake detection camera with an electronic viewfinder according to the present invention, and FIG. 3B is a diagram showing details around the shake detection optical system drive means, and FIGS. Figure 4C is a diagram showing the screen of the electronic finder, Figure 5 is a diagram showing an example of the shape of the optical system shown in Figure 3A, and Figures 6A and 6B are diagrams showing the implementation shown in Figure 5. FIG. 7 is a block diagram of the f-shake detection and correction means, and FIG.
FIG. 9 is a diagram for explaining the correlation value for determining the amount of image blur, and FIG. 10 is a diagram for explaining the interpolation calculation method. FIG. 11 is a diagram for explaining the method of driving the correction lens.
Figures A and 12B are circuit diagrams showing a circuit that controls the integration time of the CCD, and Figure 13 is a diagram showing changes in the photometric circuit output over time. The main CPU of the shake detection camera with electronic viewfinder,
3 is a flowchart for explaining the operation of a control CPU. 1 is a main CPU, 2 is an SPD, 3 is a photographic lens, 4 is an aperture drive means, 5 is a focus adjustment drive means, 6 is a photographic lens circuit, 7 is an AF detection mirror, 31 is a photometry circuit, 32 is a correction lens, 40 1 is a detection optical system, 41 is an electronic finder imaging optical system, and 42 is an optical system switching means. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] A camera capable of autofocus and capable of detecting and correcting shake, comprising: a finder screen; and a shake detecting means for detecting shake of a subject image using a light beam passing through the finder screen. A camera capable of detecting and correcting blur, wherein only the vicinity of an optical path portion of the finder screen through which the light flux for detecting the blur passes is transparent.