JP2671206B2 - Optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial applications)   The present invention is based on the relative positional relationship between two images of an object
To an optical device including a focus detection device for detecting
Things. (Background of the Invention)   Conventionally, as one type of camera focus detection device,
Light flux that splits the exit pupil of the imaging lens and passes through each pupil area
By observing the relative position displacement of the pair of images formed by
A so-called "image shift type" is known, which determines the focus state.
You.   As a signal processing method to detect the image shift amount from the image signal
Are disclosed in JP-A-58-142306 and U.S. Pat.
Although the information is disclosed, all are output from the sensor.
Focus detection processing using signals within all or fixed range
Was to do. For this reason, install it in the viewfinder.
The focus detection range, that is, the distance measuring frame is the entire area of the sensor
Smaller than the above, and is misaligned in the column direction of the sensor
In this case, the focus can be detected even if the subject is located within the ranging frame.
Cannot be detected, or conversely, focus detection for something outside the rangefinder frame
There was an inconvenience. In other words,
The field of view that differs from the actual field of view for focus detection.
In such a case, accurate focus detection could not be performed.   Conventionally, mechanical methods are used to deal with the above points.
The sensor and distance measuring frame are aligned by
Was. For this reason, it is very time-consuming and inefficient.
It was. Also, for example, different measurements may be
It is possible that you may want to change to a distance frame, but such a
In some cases, the above was remarkable. (Object of the invention)   The object of the present invention is to solve the above-mentioned problems and to perform photoelectric conversion.
Focus detection of observation means without mechanical adjustment of means
The area, the photoelectric conversion means, and the focus detection area on the pixel can be easily integrated.
An optical device that includes a focus detection device
To provide. (Features of the invention)   In order to achieve the above object, the present invention comprises a plurality of pixels.
The photoelectric conversion means and the light passing through the imaging optical system
An optical system for forming an image on a photoelectric conversion means and the photoelectric conversion means.
By performing the predetermined focus detection processing on the
The calculation means for detecting the focus state of the imaging optical system.
Focus detection device provided, and object through the imaging optical system
Observation with a focus detection area
An optical device including means corresponding to the focus detection area
The effective pixel range that produces an effective photoelectric conversion signal.
A memory means for storing is provided, so that it is stored in the memory means.
Focus detection processing is performed using photoelectric conversion signals in the effective pixel range.
It is characterized by doing so. (Example of the invention)   First of all, the focus detection principle of this type of device
It will be described with reference to FIG. Focusing lens to be detected
The field lens FLD is placed with the same optical axis as FLNS.
It is. At the rear position, symmetrically with respect to the optical axis, the two
Secondary imaging lenses FCLA and FCLB are arranged. Further behind
Sensor arrays SAA and SAB are arranged in the. Secondary imaging lens FCLA,
Diaphragms DIA and DIB are installed near the FCLB. field
The lens FLD forms two secondary images of the exit pupil of the taking lens FLNS.
Images are formed on the pupil planes of the lenses FCLA and FCLB. As a result,
The ray bundles incident on the subsequent imaging lenses FCLA and FCLB are
Each secondary imaging lens on the exit pupil plane of the shooting lens FLNS
Corresponding to FCLA, FCLB, do not overlap each other, etc.
It is ejected from the area of the area. Field Ren
The aerial image formed near the FLD is the secondary imaging lens FCLA,
When re-imaged on the surface of the sensor array SAA, SAB by FCLB,
Based on the displacement of the aerial image position in the optical axis direction, the sensor array SAA, SA
The two images on B will change their positions. Therefore, 2
If the displacement (deviation) of the relative position of the image is detected, the shooting lens
You can know the focus state of the FLNS.   No image from the image signal output from the sensor array SAA, SAB
As a signal processing method for detecting the amount of deviation, Japanese Patent Laid-Open No. 58-1423
06, JP-A-59-107313, JP-A-60-101513
The gazette and the like are disclosed by the applicant of the present application. concrete
, N is the number of pixels forming the sensor array SAA or SAB,
Image from the i-th (i = 0, ..., N-1) sensor array SAA, SAB
When signals are A (i) and B (i) OrBecomes k₁≤k ≤k_TwoIs calculated. Note that M is (M =
N- | k | -1) is the number of pixels calculated, and k is the phase
Called the amount of displacement, k₁, k_TwoIs usually taken to be −N / 2, N / 2.
And many. Here, the operator max {a, b} is the largest of a and b.
The operator min {a, b} represents that
Indicates that the smaller of a and b is extracted. Therefore, before
The term X in the expressions (1) and (2)₁(K), X_Two(K), Y
₁(K), Y_Two(K) can be considered as a correlation amount in a broad sense.
Further, looking at the equations (1) and (2) in detail, X
₁(K), Y₁(K) is actually the upper part in (k-1) displacement
X is the correlation amount defined by_Two(K), Y_Two(K) is
The correlation amount at the displacement of (k + 1) is shown respectively.
You. Therefore X₁(K), X_TwoEvaluation amount X which is the difference of (k)
(K) is the image signal A (i), B (i) at the relative displacement amount k.
Means the amount of change in the correlation amount of.   X₁(K), X_TwoThe correlation amount (k) is clear from the above definition
When the correlation between the two images is highest, it is the smallest. Yo
X (k), which is the amount of change, is “0” when the correlation is highest.
And the slope should be negative. However, X (k)
Is discrete data, so in practice X (kp) ≧ 0, X (kp + 1) <0 (3)   And, the section of the relative displacement where X (kp) -X (kp + 1) is maximum
It is thought that there is a peak of the correlation amount in the interval [kp, kp + 1]
hand, Image interpolation amount less than pixel unit
PR can be detected.   Meanwhile, Y₁(K), Y_TwoFrom the above definition, the correlation amount of (k) is
When the two images have the highest correlation, X₁(K), X_TwoThe opposite of (k)
Is the largest. Therefore, the change amount Y (k) is a correlation
It should be "0" at the highest and the slope should be positive.
You. Y (k) is the same as X (k) Y (kp) ≦ 0, Y (kp + 1)> 0 (6) And when Y (kp) -Y (kp + 1) is the maximum Image interpolation amount less than pixel unit
PR can be detected.   In addition, the focus evaluation amount of either X (k) or Y (k) is used.
Even if it is possible to detect the amount of image deviation,
As can be seen from the publication, | X (kp) -X (kp + 1) |> | Y
When (kp + 1) -Y (kp) |, the focus evaluation amount X (k)
, | X (kp) -X (kp + 1) |> | Y (kp + 1) -Y (k
When p) |, the focus evaluation amount Y (k) is used and the image shift amount PR
The S / N accuracy is better when the is calculated.   FIG. 1 is a block diagram showing one embodiment of the present invention.
PRS is a camera control circuit, for example, a CPU (central processing unit)
Processing unit), RAM, ROM, EEPROM (electrically erasable program
Mable ROM), input / output port and analog with A / D conversion function
1-chip micro computer with input port etc.
The camera sequence and AF are stored in the ROM.
(Auto focus), AE (auto exposure) control software
However, the parameters required for AF and AE control are stored in the EEPROM.
Have been. SHT is the control signal CCHT from the control circuit PRS
Data input via the data bus DBUS during input
And the shutter front curtain (not shown) based on the data
Also, the shutter control circuit that controls the running of the rear curtain and the APR are controlled.
Input via the data bus DBUS while the control signal CAPR is input.
Accept data to be input, and based on the data, not shown
A diaphragm control circuit that controls the diaphragm mechanism, DSP is a control signal CDSP
Data that is input via the data bus DBUS
Data and displays various shooting information based on the data
Display circuit, SWS is a release switch
Outside the camera, such as switches for setting various information such as
And a group of switches arranged inside the unit.   SPC is a photometric circuit and its output is analog photometry.
Signal SSPC is an analog input with A / D conversion function of the control circuit PRS.
Input to the input port, A / D converted and shutter control described above
Circuit SHT and aperture control circuit Photometric data for controlling APR
It is used as a data. LCOM receives the control signal CLCOM
Receives data input via the data bus DBUS while
On the basis of the data, the lens unit and the
It is a lens communication circuit that performs Al communication,
A record indicating the amount of movement of the shooting lens FLNS in the optical axis direction in synchronization.
Data DCL for lens drive to the control circuit in the lens described later
At the same time, the image is transmitted from the control circuit in the lens.
Lens information such as the coefficient of out-of-focus amount vs. lens movement amount of the lens FLNS.
Report DLC input serially. BSY moves the shooting lens FLNS
It is a signal to inform the camera side whether it is in the middle.
When the signal of is "H" (high level), the serial communication is
It will be impossible.   LNSU is the lens unit and LPRS is the serial input data.
Drive the motor MTR based on the DCL
The lens internal control circuit that moves in the optical axis direction, ENC is
As the lens barrel holding the shooting lens FLNS moves
The pulse signal generated by the
The encoder pulse signal EPL is
In-circuit control circuit Encoder circuit that outputs to LPRS.   SDR follows the signals STR and CK input from the control circuit PRS.
Has two sensor rows SAA, SAB, such as CCD
It is a sensor drive circuit that controls the line sensor SNS.   Next, the operation will be described with reference to FIGS. What
The shutter control circuit SHT, aperture control circuit APR, display
The operations of the circuit DSP and the photometric circuit SPC are not directly related to the present invention.
Therefore, detailed description is omitted here. Also in this embodiment
Shows the "AF" flow from the sequence flow of the camera.
It takes the form called Brutin.   When the AF operation starts, first the flag RCFLG and the flag N
Set the two flags of RSDFLG to "N" (meaning NO)
(Step 10 in Figure 2). The operation of the flags RCFLG and NRSDFLG
The details will be described later. Next, the subroutine for reading the image signal
Call Chin "IMAGE" (step 11). here
Drives the line sensor SNS via the sensor drive circuit SDR
Then, two image signals A (i) and B (i) are obtained. this
Operation of the sensor drive circuit SDR and line sensor SNS etc.
A brief description will be given with reference to FIGS. "H" from control circuit PRS
When the accumulation start signal STR is output (Step 5 in FIG. 3)
0), the clear signal CL from the sensor drive circuit SDR
It is output to the SNS and the voltage of each photoelectric conversion unit of the sensor array SAA, SAB is
The load is cleared. Then on the line sensor SNS
Secondary imaging lens, etc. (shown in FIG. 1)
However, it is arranged as shown in Fig. 15).
Photoelectric conversion of the optical image formed on the sensor array SAA, SAB
The charge storage operation is started. Is the above operation started?
After a predetermined time, the sensor drive circuit SDR
The transmission number SH is output to the line sensor SNS and is sent to the photoelectric conversion unit.
The accumulated charge is transferred to the CCD section. At the same time
The "H" accumulation end signal IEND is generated in the drive circuit SDR,
The signal is input to the control circuit PRS (step 51). So
CCD drive clock CK is output from the post-control circuit PRS
And the drive signal φ from the sensor drive circuit SDR₁, φ₂Is output
It is. This allows the line sensor SNS to follow this signal.
The analog image signal SSNS is output to the control circuit PRS.
In response to this, the control circuit PRS is synchronized with the CCD drive clock CK.
The analog image signal SSNS is A / D converted and the two image signals A
Store as (i), B (i) at a predetermined address in RAM
(Steps 52-55). Here, the pixels of the sensor array SAA, SAB
The number is assumed to be 40.   Returning to FIG. 2 again, step 12 is
Focus calculation using all pixels as the processing target range, or
Whether to perform focus detection calculation with some pixels as the processing target range
Set the processing target pixel range for round focus detection calculation
When "WD" (meaning a large out-of-focus amount) is set with the flag VSN
Is the focus detection subroutine "WPRED" and "NR"
(Meaning by the side), the focus detection subroutine "NPRE"
Call "D" (step 12). For example, in Figure 4
When the image signal is significantly out of focus,
Adopted "WPRED" to adjust the focus to near the focus as shown in Fig. 5.
Then, the subroutine "NPRED" is adopted. Note that the charge
The power-on flag VSN is set to "WD".
Since the focus state is unknown), the AF operation has started.
When it is started, "WD" is set depending on the focus state at that time.
Rui is reset to "NR". Later on this resetting
Will be described.   Focus detection when the subroutine "WPRED" is called
The processing will be described according to the flow of FIG. Steps 100-1
In 05, the relative displacement k was changed within the range of “-20 to 20”.
The focus evaluation amount X (k) at the time is calculated. Where relative displacement
The amount k is set in the range of −20 to 20 as described above.
It is assumed that the number of pixels in the sensor array SAA, SAB is "40".
However, this processing target pixel range is used for the shooting lens
It may be variable according to the focal length of FLNS.   First, in step 101, the calculation pixel is calculated by the formula M = 39− | k |
Calculate the number M. The number of calculated pixels M depends on the relative displacement amount k.
It is variable and decreases as the absolute value of k increases. this is
As the relative displacement amount k increases, the corresponding sensor output
This is because the force is missing from the end. In step 102
Check the sign (whether positive or negative) of the relative displacement amount k, and then
Pixel position P at the beginning of the calculation of A image and B image according to the number
A and PB are calculated in step 103 or 104. Step 105
Then, the focus evaluation amount X (k) is calculated.   Here, FIG. 7 shows the processing steps in steps 100 to 105.
It demonstrates using. FIG. 7 (a) shows two image signals A
(I) and B (i) are shown. FIG. 7 (b) shows k = −20.
Represents the correspondence of the sensor array for the correlation calculation in
At this time, M = 39− | 20 | = 19, PA is “0”, PB is “20”.
is there. That is, since the relative displacement amount k is a negative value, the B image is
Only the pixel (-20 pixels) is relatively displaced to the left. this
Correspondence in which B image is further displaced to the left by one pixel from the correspondence.
Is the first term of the formula when X (−20) is calculated
On the contrary, the image A is calculated by the correspondence relationship that is displaced to the left by one pixel.
The second item corresponds to the second item, respectively. This first term, second
In the section, the A image and the B image are displaced by 1 pixel each to the left and calculated.
Therefore, when calculating the calculation pixel M, M = 40− | k |
Then, M = 39− | k |. FIG. 7 (c) shows that k = 0.
It represents the correspondence of time. In FIG. 7 (d), k = 20
7 shows the correspondence of the correlation calculation in FIG.
Contrary to (b), the image A is displaced to the left by 20 pixels.   The focus evaluation amount X (k) calculated as described above is calculated by the professional.
FIG. 8 shows an example of the set products.   Returning to the flow of FIG. 6, in step 110, focus evaluation
From the amount X (k), the peak of the amount of image shift in pixel units of 2 images A and B
Find the value kp. Below, in steps 120 to 146
The lower image shift amount PR is obtained by the above step 11
Based on the peak value kp found in 0, in steps 120-135
Recalculates the two focus evaluation quantities X (k) and Y (k). This
There are two reasons. One is the previous step to find kp
Is the number of calculated pixels M is variable according to the relative displacement amount k.
Focus evaluation amount X calculated in the variable calculation range
(K) is interpolated to obtain the image shift amount PR less than the pixel unit
And the error due to the number of calculated pixels M not matching
May be included. Another one is only the focus evaluation amount X (k)
X (k), Y (k) is combined rather than the image shift amount PR is calculated with
It is better to use them together in the earlier application (Japanese Patent Laid-Open No. 60-101513)
As mentioned above, depending on the signal pattern of the subject, S / N
Because it is excellent. From the above, Step 12
From 0 to 135, the number of calculation pixels M is made constant based on kp (step
120) and the focus evaluation values X (k) and Y (k) are obtained at the same time.
I have.   First, in step 120, the calculation is performed such that M = 38− | kp |
The value of the number of calculated pixels M is determined. Then in steps 130-135
Centering on kp obtained earlier, k = kp−1, kp, kp + 1 3
At the point, the focus evaluation values X (k) and Y (k) are calculated in the same manner as above.
You. When calculating the number of calculated pixels M, M = 38− | kp |
What was done is that the absolute value of the three points of k = kp−1, kp, kp + 1
To fix the number of calculation pixels M at the maximum relative displacement
It is. Next, the focus evaluation amount X obtained as described above
From (k) and Y (k) again, the pixel singles according to each focus evaluation amount
The image shift amounts kpx and kpy are detected (steps 140 and 141).
At this time, the contrast evaluation of each focus evaluation amount X (k), Y (k)
XD (XD = X (kpx) -X (kpx + 1)), which represents the valence,
YD (YD = Y (kpx + 1) -Y (kpx)) is also obtained. This
This is based on the calculation method disclosed in the previous application in this embodiment.
Therefore, the magnitude of the image signal at the end is compared for each relative displacement.
Not (because the calculation process becomes complicated), the out-of-focus amount is large.
Contrast when the image signal information at the edges is taken into consideration
Sometimes the evaluation values XD and YD are seen as if the end of each relative displacement
Paying attention to the fact that you can obtain information as if you were looking at an image signal.
This is because the information is used for the contrast evaluation amount XD, Y
The larger D is, the better the S / N is. Therefore
In Step 142, compare the two contrast evaluation values XD and YD.
When XD ≧ YD, the focus evaluation amount X (k) is adopted (step
143), when XD <YD, the focus evaluation amount Y (k) is adopted.
(Step 144). In steps 145 and 146, the adopted ZD
(Z₁−Z_Two), Kz PR ＝ kz ＋ | Z₁/ ZD | Image interpolation amount PR is calculated by substituting pixel
You. This process is shown in FIG. In an example like this figure
Has a relationship of XD <YD, so the focus evaluation amount Y (k) is adopted.
When the image shift amount PR is calculated in pixel units or less, kz = kpy, Z₁
= Y (kp), Z_Two= Y (kp + 1) is used.   Steps 150 to 158 are processes for determining the focus state,
First, in step 150, four flags LCFLG, SDFLG, NJFFLG, JF
Set FLG to “N”. Qualitative meaning of each flag
In other words, "LCFLG" has a low contrast image signal.
It is a flag that indicates that it is a
The amount of displacement is relatively small, that is, the shooting lens FLNS
This is a flag that indicates that the amount of focus is relatively small.
“G” has a fairly small displacement between the two images, that is, the shooting lens
This is a flag that indicates that the FLNS is almost in focus.
"G" has almost no deviation between the two images, that is, in focus
It is a flag that indicates that.   Next, the contrast evaluation amount ZD of the focus evaluation amount adopted
The predetermined value LCTH is compared (step 151). This results in ZD <L
In the case of CTH, the contrast is considered to be low, and "LCFLG"
Is "Y" (meaning YES), and the subroutine "WPRED"
To end. When ZD ≧ LCTH, it is not enough to perform focus detection.
Assuming that the contrast is sufficient, go to the next step 153.
Transition. In step 153, the absolute value PR of the image shift amount PR and
When a predetermined value “3” is compared and PR> 3, that is, the image shift amount is
When it is 3 pixels or more, the subroutine "WPRED" ends.
I do. When PR ≦ 3, the out-of-focus amount is relatively small, so “SD
FLG "is set to" Y "(step 154), then PR and a predetermined value
"1" is compared (step 155). As a result, PR> 1
If the image shift amount is more than 1 pixel,
Brutin "WPRED" is finished. Omitted when PR> 1
"NJFFG" is set to "Y" because it is in focus (step 15).
6) Finally, compare PR with the predetermined value JFTH (step 15).
7). Note that the predetermined value JFTH is a value at which the image shift amount PR can be regarded as being in focus.
It is. If PR> JFTH as a result of this, here is a subroutine
End "WPRED". When PR ≦ JFTH, focus is achieved.
Therefore, set “JFFLG” to “Y” (step 158), and
Brutin "WPRED" is finished. In addition, the above four
The functions of lag LCFLG, SDFLG, NJFFLG, JFFLG will be described later.
You.   Next, the subroutine "NPRED" will be described. "N
"PRED" is a focus detection process that is applied near the in-focus point.
Of all the sensors, the range equivalent to the rangefinder frame in the viewfinder
Focus detection processing is performed only on the data within the circle. This thing
FIG. 10 showing the positional relationship between the finder and the sensor array SA
This will be described with reference to FIG. In the figure, FFRM is on the viewfinder
It is a distance measuring frame. Distance measurement frame FFR in subroutine "NPRED"
M range further R₁, R_Two, R_ThreeDivided into 3 areas as shown in
Area R in the ranging frame FFRM for each part₁, R_Two, R_ThreeIs the sensor row
Which pixel of SA corresponds to the beginning of each part
Pixel position NR₁, NR_Two, NR_ThreeIn advance during the adjustment process
It is stored in the EEPROM in the control circuit PRS. At this time to each part
The included NNPX are the same (R₁= R_Two= R_Three) And this value NNPX
Similarly, it is also stored in the EEPROM. In this example, NNPX
= 12, NR₁, NR_Two, NR_ThreeAre "8", "14" and "20" respectively
Yes, (NNPX + k) is the processing target range in this case
(The shaded area in Figure 12). These values are the optical system for focus detection
And several pixels depending on the installation status of the line sensor SNS
Although it may shift, it is stored in the EEPROM as described above.
Therefore, the range of calculation for performing focus detection processing with the focus detection frame FFRM
Can be matched. For the image signal of FIG.
Showing R₁, R_Two, R_ThreeIs the above subroutine "NPRED" processing
Is a divided area in.   The first operation when the subroutine "NPRED" is called
It will be described according to the flow of Fig. 1. Number of pixels calculated in step 200
Let M be NNPX. In the above-mentioned subroutine "WPRED"
Although the number of calculation pixels M was variable according to the relative displacement amount k,
This focus detection process is fixed to NNPX. This is WP
"RED" uses all pixel output for calculation, while "WPRE"
In “D”, the displacement of the sensor array SA is used because part of the output is used.
May cause data at the end of the corresponding sensor output to be lost.
Because there is nothing. Therefore, in "NPRED", "WPRED"
The number of calculation pixels M performed in steps 120 to 141 of is fixed.
No recalculation is done. Also, say that the recalculation is not
Therefore, the evaluation quantities X (k) and Y (k) are calculated simultaneously from the beginning.
To seek.   Steps 210-221 are area R₁Focus on image data
This is a detection process. The same processing parts as "WPRED" in the figure are the same
The same step number is attached. Subroutine "NPRED"
Then, the range of the relative displacement amount k is set to (-4 to 4). This
This is what "NPRED" is applied near focus.
Therefore, the image shift amount is originally small. In this case
Region R, as shown in steps 212 and 213₁Start position NR₁Is considered
Is being considered. This process is shown in FIG. 13 (a). Figure
The solid line represents the focus evaluation amount X (k), and the broken line represents Y (k).
You. The same process as described in "WPRED" (Step 1
40 ~ 146) according to area R₁Image displacement amount PR₁Ask for.
PR in step 221₁And contrast evaluation amount ZD₁To
It is stored in the RAM in the control circuit PRS. Similarly, step
Area R from 230 to 241_TwoImage shift amount PR at_Two, Con
Trust evaluation amount ZD_Two(See Fig. 13 (b))
Up 250-261 area R_ThreeImage displacement amount PR_ThreeContra
Strike amount ZD_Three(See Fig. 13 (c))
It is stored in the RAM in the control circuit PRS.   In steps 270-278, the three
Area R₁, R_Two, R_ThreeImage shift amount PR₁, PR_Two, PR_ThreeWhich of
Determine whether to use the image shift amount as the final image shift amount PR
Is going. That is, in this embodiment, the
The trust is high enough and the maximum image shift amount is adopted.
I am trying to do it. Adopt the maximum image shift amount here
The meaning is that the rear focus is set when the image shift amount is positive, and the rearmost focus is set.
The subject is the closest subject, and
It means focusing on the body. The final image
After obtaining the amount PR and the contrast evaluation amount ZD, step 28
The focus state is determined at 0. Processing here is "WPRED"
Since the processing is the same as that described above, the description thereof is omitted.
You.   As described above, when the amount of defocus is large
By the subroutine "WPRED",
Is the amount of image shift at that time by the subroutine "NPRED",
That is, it is possible to detect the out-of-focus amount of the shooting lens FLNS.
it can.   Returning to FIG. 2, the explanation from step 15 is continued. S
Step 15 sees the flag LCFLG, "WPRED" or
Check the contrast during focus detection processing of “NPRED”.
Check. When LCFLG is “Y”, the contrast is low
Then, in the next focus detection process, use "WPRED".
Set lag VSN to "WD" (step 35) and display subroutine
Execute "DISP" and lens control subroutine "LENS"
(Steps 19, 20). The display subroutine "DISP" is
Since it is not directly related to the present invention, it is omitted here.
The control subroutine "LENS" will be described later.   In step 16, the flag VSN is checked again. VSN
When it is "WD", the processing from step 17 onwards is performed, and when it is "NR"
To do this, the processing from step 28 onward is performed.   First, the processing when VSN = "WD" will be described. VSN = "WD"
Indicates that the previous focus detection process was performed with "WPRED".
You. In step 17, the flag RCFLG is checked. RCFLG
When performing focus detection processing twice in the "AF" routine
It is "Y". In this embodiment, the "AF" routine is
When executing, first use "W" with the VSN set in the previous "AF".
Execute either "PRED" or "NPRED".
VSN is set to "WD" in the early stage
However, the resulting image shift amount depends on each condition.
When not touching, reset VSN and set flag RCFLG to "Y".
This time, different focus detection processing "NPRED" or "WPR
ED ”will be executed. RCFLG is a flag for that
It is. The VSN resetting will be described later.   Flag RCFLG is "N", that is, the first focus detection process
At this time, the flag SDFLG is checked (step 18). SDFLG
Is set in "WPRED" or "NPRED" as described above.
Flag (SDFLG in this step is set in “WPRED”)
Defined), when this flag is "Y" (within 3 pixels)
Means that the current focus state is relatively close to focus
You. Therefore, VSN is "WD" and SDFLG is "N" (3 pixels or more)
If so, display "WPRED" as appropriate.
Chin "DISP", lens control subroutine "LENS" execution
Move to. On the other hand, if SDFLG is “Y”, then “NPRED”
It is more appropriate to recalculate, that is, the accurate image shift amount PR
And set VSN to “NR” (step
21) and temporarily store the image shift amount PR in the buffer BPR (step
22), set RCFLG to “Y” (step 23), and then restart
Routine from step 12 (actually step 12 → step
14 → step 15 → step 16 → step 28 → step 33
→) is executed. No image in step 22
The reason for temporarily storing the amount PR in the buffer BPR is as follows.
If the result calculated by the routine "NPRED" is not appropriate
In other words, as a result of calculation with “NPRED”, in step 33
If the SDFLG is "N" (3 pixels or more), the subroutine
Chin "WPRED" To adopt the image shift amount PR obtained in the first time
(Step 34 → step 27 →).   When RCFLG is “Y” in step 17, that is, the second focus detection.
For output processing, go to step 24 and check SDFLG here.
To click. As a result, if SDFLG is "N", focus at this time
Since the exit distance is "WPRED", the focus detection process here is
Display as appropriate Subroutine "DISP", lens control
Move to execution of the subroutine "LENS". Also, SDFL
If G is "Y", is RCFLG "Y" and VSN "WD"?
, The first focus detection process is performed by "NPRED", and
The result is "NPRED", which is not appropriate. Later
However, in the first "NPRED", the flag NJFFLG
"Y", that is, it is not appropriate unless it is in focus
However, if SDFLG is “Y”, flag NRSDFLG is set to “Y” (combined).
It is not in focus, but within 1 pixel). That is, NR
If SDFLG is "Y", it is omitted in the first "NPRED"
It is not in focus, but it means that it was relatively close to focus
You. At this time, the image shift amount PR in “NPRED” is equal to the buffer BPR.
When stored. Therefore, in step 24, SDFLG is "Y".
If you say, "WPRED" is relatively close to focusing on the second time
Therefore, it is necessary to refer to the result of "NPRED" for the first time.
Check flag NRSDFLG at p.25. NRSDFLG here
If is "N" (1 pixel or more), the first time is not appropriate
"WPRED" is displayed using the second image shift amount PR.
Brutin "DISP", lens control subroutine "LENS"
Shift to execution. If NRSDFLG is "Y", the next "A
In "F", VSN should be set to "NPRED" for the first focus detection process.
Is set to “NR” (step 26) and already stored in the buffer BPR.
Take out the amount of image shift PR in the first "NPRED"
(Step 27), display subroutine "DISP", lens control
Temporarily shifts to the execution of the subroutine "LENS".   Go up the flow and in step 16 the VSN is judged to be "NR".
If so, the flag RCFLG is checked in step 28.
Here, when RCFLG is "N", the first "NPRED" is changed to "Y".
Time means the second time of "NPRED". In case of “N”
Check SDFLG in step 29. When SDFLG is "N"
The second focus detection process, because "NPRED" is not appropriate
VSN is set to “WD” (step
30), temporarily store the image shift amount PR in "WPRED" in the buffer BPR
Store (step 22) and set RCFLG as “Y” (step 2)
3) Go back to step 12 and execute the routine again.
(Actually, step 12 → step 13 → step 15 → step
Step 17 → Step 24 →). Steps
When SDFLG is “Y” at 29, flag NJFFL at step 31.
Check G. This was explained in step 25 above
However, in the first "NPRED", focus detection processing by NJFFLG
It is determined whether or not was appropriate. NJ in step 31
If FFLG is "N" (1 pixel or more and 3 pixels or less), it is almost in focus
If not, but relatively close to focus,
The second step of the focus detection process "WPRED"
Flag NRSDFLG “Y” for use in
Then, the process proceeds to step 30. Also, in step 22,
"NPRED" temporarily stored in the FA BRP PR of the first image shift
As needed, ie “WPRED” on the second step 27
Used in   When RCFLG is “Y” in step 28, “NPRED” twice
It is the eye, and as you can see from the above, the first time is "WPRED"
It means that the result was judged to be inappropriate. or
As mentioned above, check SDFLG in step 33 and click "Y"
If so, "NPRED" is judged to be appropriate for the second time, and the image as it is
Displacement PR display subroutine "DISP", lens control sub
Move to execution of routine "LENS". SDFLG is "N"
If there is, "NPRED" is not appropriate for the second time, and the next "AF"
VSN to set the focus detection process in "WPRED"
Set to "WD" (step 34) and temporarily store "WPRED" for the first time
Take out the image shift amount PR stored in the buffer BPR
(Step 27), display subroutine "DISP", lens control
Move to execution of the subroutine "LENS".   The flow of the above "AF" processing can be briefly summarized as "A
When "F" is called, the image signal of the sensor array SA is read
(“IMAGE”), focus detection processing “WPRED” or “NPRE”
"D" is performed, but "WPRED" has a large out-of-focus amount
Sometimes the premise that "NPRED" is applied near the focus
The detected image shift amount is unsuitable for the processing at that time.
In such a case, the same image signal is recalculated and combined using an appropriate processing method.
The image shift amount PR used for the local lens control has a large defocus amount.
"WPRED" when there is no light, and "NPRED" when near focus
It will be calculated more. In other words, the out-of-focus amount is large
Sometimes it is not appropriate to perform focus detection processing with "WPRED".
The in-focus state is clearly understood, and this result is determined to be near the in-focus state.
If it is turned off, focus detection processing is performed by "NPRED".
This is because the accuracy of focus detection can be improved by using this method.   On the contrary, the subroutine "LENS" is used by using the flow of FIG.
Will be described. Check the flag LCFLG in step 60.
Click. This flag is the target of focus detection processing as described above.
When the contrast evaluation amount of the image signal is
ing. When LCFLG is "N", the focus detection process is applied to the image signal.
If the contrast is reasonably sufficient,
The taking lens FLNS is controlled on the basis of the image shift amount PR.
First, check the signal BSY input to the lens communication circuit LCOM
Yes (step 61). While this signal BSY is "H", the lens
Since it cannot communicate with the internal control circuit LPRS, the signal BSY
Wait until it becomes "L" (low level). The signal BSY is
When it becomes “L”, the control circuit LPRS in the lens changes the shooting lens FL
The coefficient S of the NS defocus vs. lens movement amount is referred to as the signal DLC.
Input (step 62). Next, from the image shift amount PR
The defocus amount DEF of the lens FLNS is changed to the formula DEF = K · PR.
To calculate (step 63). K is the focus detection optical system
The value is set in advance and is set in advance. Then Def
Moving amount FP of shooting lens FLNS from focus amount DEF and coefficient FP
Is calculated by FP = DEF / S (step 64). FP is Enco
Equivalent to the count number of the feeder circuit ENC. And step
Check the signal BSY again at page 65, and confirm that the signal BSY is “L”.
Then, the lens movement amount FP (signal DCL) is controlled within the lens.
Communicate to the control circuit LPRS (step 66). On the other hand, LCFLG
When it is “Y”, the contrast is not enough,
In order to perform the search operation, the moving amount FP of the shooting lens FLNS is FP =
Calculate with CDEF / S (step 67). CDEF is one search
Converts the lens movement amount that is moved during operation to a defocus amount
However, it is preset.   The lens movement amount FP is input to the control circuit LPRS in the lens.
Then, the drive control of the taking lens FLNS is performed based on the information.
U. Image signal A when the shooting lens FLNS is stopped
(I), a series of focus adjustments starting from the input of B (i)
The "AF" process ends.   According to this embodiment, the pixels corresponding to the viewfinder distance measuring frame
The range (effective range) of EEPR
Since it is stored in the OM, mechanical adjustment
It becomes unnecessary and the work efficiency is very good. Also,
Cameras with the same structure, only viewfinder distance measurement frame
To a different one (matte surface, split image)
Even if you want to, you can easily change it. Furthermore, the group
If it is found that the sensor has uneven sensitivity after the stand is finished.
Or if it is found that the AF optical system has aberrations
It is easy to avoid using that part, etc.
Wear. (Correspondence between invention and embodiment)   In this embodiment, the taking lens FLNS is the imaging light of the present invention.
Field system FLD, secondary imaging lens FCLA, FCL
B is the optical system, and the sensor arrays SAA and SAB are photoelectric cells consisting of multiple pixels.
The conversion means, the CPU functions as the calculation means, and the EEPROM functions as the storage means.
Hit (Modification)   In this embodiment, the "image shift type" device has been described.
However, the focal plane is not limited to this.
So-called "sharpness type" focus detection that detects strike changes
It can also be applied to a device. (The invention's effect)   As described above, according to the present invention, the focus of the observation means is
Generates a valid photoelectric conversion unit signal corresponding to the point detection area
A storage means for storing the effective pixel range is provided.
The photoelectric conversion signal of the effective pixel range stored in the storage means
Since more focus detection processing is performed, photoelectric conversion means
The focus detection area of the observation means without any mechanical adjustment of
And the focus detection area on the pixel of the photoelectric conversion means can be easily matched.
Can be made.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an example of a focus adjusting device for a camera suitable for carrying out the present invention, FIG. 2 is a partial flowchart thereof, and FIG. Flow charts, FIGS. 4 and 5 are diagrams showing an example of an image signal output from the sensor array, FIG. 6 is a partial flow chart, and FIG. 7 is a diagram showing a correspondence relationship between two images at the time of focus detection calculation. , FIG. 8 is a diagram showing a change in the evaluation amount, FIG. 9 is a diagram showing a part of the change in the evaluation amount, FIG. 11 is a partial flowchart, and FIG. 10 is a viewfinder distance measuring frame and sensor array. Figure 12 showing the positional relationship
The figure shows the correspondence between the two images during focus detection calculation. Fig. 13 shows a part of the change in the evaluation amount. Fig. 14 shows a part of the flowchart. Fig. 15 shows a general secondary result. It is a layout showing an optical system of the image-based focus detection device. PRS ... Control circuit, LCOM ... Lens communication circuit, LNSU ...
Lens unit, SDR …… Sensor drive circuit, SAA, SAB ……
Sensor array, FLNS …… Shooting lens, k …… Relative displacement.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Yasuo Suda               770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa               Inside the Tamagawa Office of Canon Inc. (72) Inventor Ichiro Onuki               770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa               Inside the Tamagawa Office of Canon Inc. (72) Inventor Keishi Otaka               770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa               Inside the Tamagawa Office of Canon Inc. (72) Inventor Takeshi Koyama               770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa               Inside the Tamagawa Office of Canon Inc.                (56) Reference JP-A-58-150918 (JP, A)

Claims (1)

(57) [Claims] By performing a predetermined focus detection process on a photoelectric conversion signal from the photoelectric conversion unit, a photoelectric conversion unit composed of a plurality of pixels, an optical system that forms an image of the light passing through the imaging optical system on the photoelectric conversion unit, In a focus detection device including a calculation unit that detects a focus state of the imaging optical system, and an optical device including an observation unit for observing an object through the imaging optical system and including a focus detection region. An optical device comprising: storage means for storing an effective pixel range corresponding to the focus detection area for generating an effective photoelectric conversion signal.