JPH0320706A - Automatic focus detecting device - Google Patents

Abstract

PURPOSE:To detect relative displacement in a short time by performing focus detection by using a secondary filter means and a 2nd focus detecting means unless a focus is detected by a primary filter means and a 1st focus detecting means. CONSTITUTION:A central controller 26 controls the whole camera to calculate exposure, etc., and also extracts a 1st spatial frequency component by the primary filter means. The 1st focus detecting means performs focus detection according to the extracted spatial frequency component. Further, the secondary filter means extracts a 2nd spatial frequency component and the 2nd focus detecting means performs focus detection according to the extracted component. Then only when the 1st focus detecting means decides that focus detection is impossible, the secondary filter means and 2nd focus detecting means are put in operation. Consequently, when the 1st focus detecting means decides that focus detection is possible, the detection time can be shortened without operating the secondary filter means.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a moving focus detection device for an optical device such as a camera that detects the focus adjustment state of an imaging optical system that forms an optical image of a subject. It is.

(Prior Art) Conventionally, two optical images of almost the same part of a subject are guided onto a pair of photoelectric conversion element arrays consisting of a plurality of photoelectric conversion element arrays, and the outputs of the photoelectric conversion element arrays are calculated. There is an automatic focus detection device that detects the relative displacement of the optical image on the photoelectric conversion element array and adjusts the focus of a lens based on the detection result. Further, a plurality of specific frequency components of the subject image are extracted from the output of the photoelectric conversion element array using a plurality of filter means (primary filter means, secondary filter means, etc.), and a calculation is performed based on these frequency components. There is an automatic focus detection device that detects the relative displacement of an optical image by performing
-875 November Publication, JP-A-59-142506, JP-A-60-151607, Special rM Sho 61-2
See Publication No. 09413>.

[Problem to be solved by the invention]

However, in conventional automatic focus detection devices, each filter means always extracts the frequency components of the subject image.
For example, even if the relative displacement of the optical image can be detected even if calculation is performed using only the frequency components extracted by the primary filter means, all the filter means are operated. Therefore, there is a problem in that it takes time to detect the relative displacement. Furthermore, since a memory such as a RAM for storing data of extracted frequency components is required for each filter means, there is a problem in that a large amount of memory is required.

The present invention provides an automatic focus detection device that operates a secondary filter means to detect the relative displacement of an optical image when the relative displacement of the optical image cannot be detected even by calculation using the primary filter means. The purpose is to

[Failure to solve the problem]

In order to achieve the above object, the present invention includes: a primary filter means for extracting a first spatial frequency component; a first focus detection means for performing focus detection based on the extracted spatial frequency component; a secondary filter means for extracting a second spatial frequency component based on the extracted spatial frequency component; and a second focus detection means for performing focus detection based on the spatial frequency component extracted by the secondary filter means. , a determining means for operating the secondary filter means and the second focus detecting means when it is determined that the first focus detecting means cannot detect the focus.

[Effect]

According to the automatic fish point detection system having the above structure, the secondary filter is activated when the focus cannot be detected even with the use of the primary filter, so the focus can be detected using only the frequency components extracted by the primary filter. In this case, the time required for extracting frequency components by the secondary filter means can be reduced. In addition, when detecting a focus using the frequency components extracted by the secondary filter means, the frequency components extracted by the secondary filter means are stored in a memory such as a RAM that stores data of the frequency components extracted by the primary filter means. data can be stored.

(Embodiment) FIG. 1 shows an embodiment of the schematic structure of a camera equipped with an automatic focus detection device according to the present invention. The automatic focus detection device 111 is composed of a photographic lens 2, a focus detection means 3, a defocus amount determination means 4, a lens position detection means 5, a lens drive means 6, and a control means 7. This photographing lens 2 guides a light beam 9 emitted from a subject 8 to a focus detection stage 3.

The focus detection means 3 has a photoelectric conversion element array (not shown), and processes the output of the photoelectric conversion element array to detect the relative displacement of the light by the subject 8 on the photoelectric conversion element array. It is something.

Furthermore, the defocus amount determining stage 4 is the focus detection stage 3.
The defocus amount of the decoy lens 2 is determined based on the displacement detection signal output from the decoy lens 2. The lens position detection means 5 is for detecting the current position of the shadow lens 2. The lens driving means 6 is the defocus amount determining means 4.
The carrier lens 2 is driven based on the defocus amount signal. The control means 7 tillllll the lens driving means 6 so that the m shadow lens 2 is driven to a position corresponding to the defocusing, and also performs the focus detection?
When the matching signal is output from the means 3, the driving of the m-photo lens 2 is stopped.

FIG. 2 shows an embodiment of the mechanical configuration of the focus detection stage 3. The focus detection stage 3 is composed of a main mirror 10, a mirror 11, and a focus detection optical system 12. This main mirror 10 branches the light beam 9 that has passed through the carrier lens 2 into a finder optical system and a sub-mirror 11 (not shown). The mirror 11 further branches the light beam 9 branched by the main mirror 10 to a focus detection optical system 12ε film surface 13.

The focus detection optical system 12 includes a photoelectric conversion element array 141,
142.143 and separator lens 15 and aperture mask 1
6 and Mojico, 1 Lumirror 17 and Condenser Lens 181
, 182, 183 and a field stop 19t. The photoelectric conversion element arrays 141, 142, and 143 are arrays of a plurality of CCOM image elements, etc., and are formed on one chip above the focal point 14 of the separator lens 15.

The separator lens 15 is a separator lens pair 151,1
52.153, and projects the branched light beam 9 onto photoelectric conversion element arrays 141, 142.143.

The aperture mask 16 has a circular or oval opening 161,
162.163, and limits the light flux 9 input to the separator lens 15. module mirror 17
is for guiding the light beam 9 that has passed through the condenser lenses 181, 182, and 183 to the separator lens 15. The field stop 19 has rectangular openings 191, 192, and 193, and is arranged near the focal plane, and is connected to the focus detection optical system 12.
This is to limit the field of view of the light beam 9 input to the.

FIG. 3 shows the photoelectric conversion element array 141, 142, 14.
3 (hereinafter referred to as a CCD including the light receiving section, storage top, and transfer section of the photoelectric conversion element). This photoelectric conversion element array 141 includes a reference portion 141a and a reference portion 141.
Similarly, the photoelectric conversion element array 142 consists of a reference part 142a, a reference part 142b, and a photoelectric sensor 142C, and the photoelectric conversion element array 14
3 is a reference part 143a, a reference part 143b, and a photoelectric sensor 14
It consists of 3C. The photoelectric sensor 14LC. 142c.
143c are the reference parts 141a, 142a. 143
It is disposed in the longitudinal direction on one side of the lens a, and outputs a signal according to the light received. Then, the accumulation time of COD in the 'a' accumulation part is controlled by the month corresponding to the light receiving period. In addition, as shown in FIG. 4, the photoelectric conversion element arrays 141, 142, and 143 are connected to fish point detection areas 1121, 22, and 23, respectively, located in the center of the shadow removal screen 20 in the finder. 21, 2nd island 22. A displacement detection signal is output based on the optical image of the subject 8 projected onto the third island 23).

An area 24 indicated by a dotted line in the center of the embroidery image screen 20 is for displaying to the photographer the area where focus detection is being performed.

Further, the display section 25 lights up when the image is in focus.

The number of pixels in each of the reference portions 141a, 142a, and 143a
, and reference portions 14lb, 142b. For example, as shown in FIG. 3, in the photoelectric conversion element array 141 and the photoelectric conversion element array 143, the number of pixels Y in the reference part is 34, and the number Y of pixels in the reference part is 4.
In the photoelectric conversion element array 142, the number of pixels X in the reference part is 44, and the number Y of pixels in the reference part is 52.

Further, in the automatic focus detection device 1, the reference portion 1 4 1 a.
142a. The data of each pixel of 143a is divided into a plurality of blocks, and each divided block is compared with all the data of each reference section 14lb, 142b, 143b to perform focus detection. Then, among the focus detection results in each block, the data of the rearmost bin is used for each island 2.
The focus detection data of 1.22.23, and the focus detection data of each island 21.22.23 and m-sho lens 2.
Based on the data of the image transport magnification, the high-density lens 2 is driven and focused.

Next, the photoelectric conversion element arrays 141, 142, 14
Regarding the means for determining the range (defocus range) for detecting the amount of defocus (i.e., the deviation in the optical axis direction between the intended focal plane of the imaging optical system and the image plane of the subject) from 3. This will be explained using FIGS. 5 to 7.

Figure 5 shows each island 21, 22, 23 shown in Figure 3.
This is an enlarged view of reference portions 141a, 142a, and 143a corresponding to . In the figure, each reference portion 141
a. The numerical values shown in 142a and 143a correspond to the reference parts 141a and 142a shown in FIG. The difference (i.e.,
(spatial frequency component). Moreover, this difference data indicates a component of a specific spatial frequency extracted (filtered) from the pixel data.
spatial frequency component extraction means). Note that the difference data may be every two or every other data. However, the spatial frequency components are different from those obtained when three components are taken directly, and the numerical values are also different.

Reference parts 141a, 14 of each island 21, 22.23
2a. The numerical value in 143a is the first island 2
1 has 30 pieces, 2nd island 22 has 40 pieces, and 3rd island 23 has 301 pieces! ! Become II. Further, reference portions 14lb, 142b. 143b as well as the reference part 141
a. 142a. It is obtained in the same way as the numerical value of the difference data of 143a. That is, the reference portions 14lb, 142b. 143
The numerical value of b is 40 for the first island 21, 48 for the second island 22, and 40 for the third island 23.

Next, block division in each island 21, 22, and 23 will be explained. That is, in the first island 21, K1 (1 to 20>, κ1<<11
~30) are divided into two blocks, and are respectively referred to as a first block B11 and a second block BL2. In the second island 22, κ2 (1 to 20), K
2 (11-30), K2 (2 1-40), and the third block BL3 and the fourth block, respectively.
It is assumed that the block B14 and the fifth block BL5. In the third island 23, K3 (1 to 20
), K3 (11 to 30) are divided into two blocks, the younger brother 9 block BL9 and the 10th block BLIO.

Furthermore, the second island 22 detects difference data with different extraction frequencies in order to focus on the subject consisting of low frequency components (second spatial frequency component extraction means), and uses this difference data to the sixth block BL6, It is divided into a seventh block BL7 and an eighth block BL8 and used for focus detection data. That is, the data of each pixel in the standard part 142a and the reference part 142b is differenced, for example, every seventh pixel, the sum of the difference data between adjacent pixels is found, and the data of this sum is sent to the sixth block BL5. do. In other words, the number of differential data 6 is 36 in the reference section 142a and 44 in the reference section 142b, and the total number of data in the sixth block BL5 is 35 in the M quasi-section 142a and 44 in the reference section 142b. 14
In 2b, there are 43 pieces. Of the 35 reference portions 142a, the 25 pieces on the left side are the seventh block BL7, and the 25 pieces on the right side are the eighth block BL8.

Note that, in the above, the interval between the differences is set every seven, but the larger the interval, the more low frequency components can be extracted. In other words, the interval between the differences may be set to an interval other than every seven.

In this focus detection means, when the optical images of the reference part and the reference part match, when the image interval is larger than a predetermined interval, the rear bin is focused, when it is smaller, the front bin is focused, and at the predetermined interval, the image is focused. Therefore, the defocus range of the divided blocks is determined by blocks farther away from the optical center within each island, the closer the blocks are to the rear bin.

FIG. 6 shows an enlarged view of the reference portion 142a and the reference portion 142b of the second island 22, and the defocus range of the fourth block BL4, which is divided into blocks, will be explained using this figure. In other words, the 41st Ock BL of the reference part 142a
In order to focus on the image No. 4, the data of the block BL41 located at the center of the reference section 142b, that is, the image located 34th from 15'#1 from the left end of the reference section 142b, and the data of the image No. 4 of the fourth block B[4] are used. This is when the data K2 (11 to 30) match. From this, the image matches the reference part 1.
The left side of 42b is the previous bin, and the maximum number of deviation data (hereinafter referred to as deviation pitch) of the previous bin is 14. On the other hand, when the images coincide on the right side of the reference portion 142b, the rear is out of focus, and the deviation pitch of the rear bin becomes 14.

The same applies to the first island 21 and the third island 23. That is, as shown in Figure 7,
In the third block BL3, there are 4 front bin side deviation pitches,
The rear bin side shift pitch is 24 pieces, and the 570th Tsuku BL
In No. 5, there are 24 pitches deviating from the front bin side and 4 pitches deviating from the rear bin side.

Furthermore, in the first block BLl and the ninth block BL9, the front bin side deviation pitch is 5 pieces and the rear bin side deviation pitch is 15 pieces, and in the second block BL2 and the tenth block BL10, the front bin side deviation pitch is There are 15 bits, and 5 bits are off to the rear bin side. Furthermore, the 6th block 8m
5, the shift pitch is 4 on both the front bin side and the rear bin side.

In the seventh block BL7, there are 4 front bin side deviation pitches,
The rear bin side shift pitch is 14, and the 8th block BL
8, the front bin side deviation pitch is 14 pieces and the rear bin side deviation pitch is 4 pieces, but since the deviation pitch overlaps with the sixth block BL6, in the seventh block BL7, there are 4 to 14 pieces on the rear bin side. In the eighth block BL8, the defocus range is set to 4 to 14 shift pitches on the front bin side.

FIG. 8 shows an embodiment of a camera circuit block in which an automatic focus detection device according to the present invention is constructed using a microcomputer.

A central control circuit (hereinafter referred to as a microcomputer) 26 controls the entire camera, calculates exposure, etc., extracts the first spatial frequency component (primary filter means), and adjusts the focus based on the extracted spatial frequency component. detection (first focus detection means), further extracting a second spatial frequency component based on the extracted spatial frequency component (secondary filter means), and extracting a second spatial frequency component based on the extracted spatial frequency component (secondary filter means). Focus detection is performed based on the component (second focus detection means)
, when it is determined that the focus cannot be detected by the first focus detection means, the secondary filter means and the second focus detection means are activated (determination means).The lens circuit 27 is connected to the camera body. This is to transmit data specific to the photographing lens 2 (interchangeable lens) mounted on the camera (not shown) to the microcomputer 26. The focus detection data output circuit 28 corresponds to the focus detection stage 3 in FIG. The brightness detection circuit 29 detects the brightness of the subject 8 by measuring the luminous flux 9 that has passed through the Zuisho lens 2, and transmits the abex IBvo corresponding to this brightness to the microcomputer 26. The film sensitivity reading circuit 30 reads the film sensitivity from a film (not shown) and transmits an abex value Sv corresponding to the film sensitivity to the microcomputer 26.

The display circuit 31 displays exposure information and the focal state of the projection lens 2. The encoder 32 detects the amount of rotation of the lens drive motor 33, and outputs the number of pulses corresponding to a predetermined amount of rotation of the lens drive motor 33 to a lens drive control circuit 34, which will be described later. Lens drive III11
The circuit 34 inputs a motor drive direction signal and a motor stop signal from the microcomputer 26, and controls the drive of the lens drive motor 33 based on these signals.

Additionally, a counter is provided inside the microcomputer 26. This counter detects the extended position of the Wi shadow lens 2 from the infinite position, and is designed to count up or down with respect to the number of pulses. Further, when the power switch (main switch) SW1, which will be described later, is turned on, and the photographic lens 2 is driven and the photographic lens 2 is retracted to the infinity position,
The counter is adapted to be reset.

The power supply battery 35 directly supplies power to the microcomputer 26 and switches described below, and supplies power to other circuits via a power supply circuit 36 described later. Power supply circuit 3
Reference numeral 6 supplies power to circuits such as the lens circuit 27 and the focus detection data output circuit 28 based on a control signal from the microcomputer 26.

The power switch SW1 starts or stops the operation of the camera when opened or closed. The one-shot circuit 37 generates a predetermined pulse in conjunction with the opening/closing operation of the power switch SW1, and inputs this pulse to the microcomputer 26. Akira Iso preparation switch SW
2 is opened and closed by operating a release switch (not shown), and when this removal preparation switch SW2 is turned on, a focus detection operation is started. Limit switch SW3 is II! This is turned on when the lens 2 is retracted to an infinity position or extended to the most extreme position. The selection switch SW4 is used to select automatic focus adjustment mode (hereinafter referred to as AF mode) or focus detection display mode (hereinafter referred to as FA mode).When this selection switch SW4 is turned on, it becomes FA mode, and when it is turned off. Then the camera will enter AF mode.

Next, the operation of the camera with the above configuration will be explained.

First, when the power switch SW1 is turned on, a pulse is output from the one-shot circuit 37 to the interrupt input terminal [N10 of the microcomputer 26, and the microcomputer 26 executes the interrupt operation flowchart shown in FIG.

In other words, the microcomputer 26 prohibits the focus detection operation due to the turning on of the focus preparation switch SW2 (step #1), and determines whether this interrupt operation is due to the turning on or turning off of the power switch SW1 via the interrupt input terminal IP of the microcomputer 26.
The determination is made based on the voltage input to step #1 (step #2).

And if this input voltage is high voltage, step #
Without performing the processes 3 to #11, power to the lens circuit 2827 and the like is stopped, and the microcomputer 26 enters an operation standby state (steps #12 and #13). If this input voltage is low-m voltage, the power switch SWt is determined to be on, and the operation of the counter in the microcomputer 26 is prohibited (step #3).
Set the flags used to execute the flowchart and the output terminals of the microcomputer 26 (Step #4)
.

Next, the output terminal OP1 of the microcomputer 26 is set to high voltage to supply power to circuits such as the lens circuit 27 (step #5>). The bow is input, and the carrying lens 2 is retracted toward the infinity position (step #6).Then, the LA shadow lens 2 is retracted to the infinity position, and wait for the limit switch SW3 to be turned on ( Step #7).

When the limit switch SW 3 is turned on in step #7, the driving of the Chusho lens 2 is stopped (step #8)
.

Along with this, a counter in the microcomputer 26 is reset to count the number of pulses corresponding to the rotation rate of the lens drive motor 33 (steps #9 and #10). and,
Interruption of the focus detection operation by turning on the photographing preparation switch SW2 is enabled (=1) (step #11).

Then, the output terminal OP1 is set to a low voltage and the lens circuit 2
7, etc., and keep them in operation until the shooting preparation switch SW2, etc. is pressed (steps #12 and #13).
).

Furthermore, if the starvation*Ifi switch SW2 is turned on during the operation standby state in step #13, the microcomputer 26
executes the interrupt operation flowchart shown in FIG.

That is, the microcomputer 26 initializes the flags used to execute the flowchart and the output terminals of the microcomputer 26 (step #21). Furthermore, a timer provided in the microcomputer 26 is reset, and then this timer is started (step #22). Then, a flag AFSF indicating that this is the first sunspot adjustment operation is set (step #23), and the output terminal OP1 is set to a high voltage to supply power to the lens circuit 27, etc. (step #23).
24). Next, data consisting of coefficients for converting focal length data, open aperture value, defocusing, etc. of the decoy lens 2 into the number of pulses for driving the lens is sent to the lens circuit 2.
7 (step #25). Then, difference data is input from the focus detection data output circuit 28, and this difference data is stored (steps #26 and #27). Next, the defocus amount of each of the islands 21, 22, and 23 described above is calculated, and furthermore, exposure calculation is performed, and the results of these calculations are displayed on the display circuit 31 (steps #28 to #2).
30).

Next, it is determined whether it is the FA mode or the AF mode (step #31), and if it is the AF mode, calculate the driving position of the picture lens 2 from the defocus lens, and based on this, m Drive the lens 2 <<Step #32>>. On the other hand, if it is FA mode in step #31, step #
The process moves to step #34 without performing the process of step #32. In step #34, it is determined whether the m-shadow preparation switch SW2 is open or closed.

If the concession preparation switch SW2 is on, the flag AFSF is reset (step #35), the process returns to step #25, and the processing from step #25 is repeated. On the other hand, if the photographing preparation switch SW2 is off in step #34, the power supply circuit 36 is turned off and the lens circuit 27 is turned off.
etc. [Step #36], llffl
The operation is kept on standby until the light preparation switch SW2 or the like is pressed (step #37). And the detailed image preparation switch SW
When 2 etc. is pressed, the process moves to the flowchart shown in FIG.

Next, the subroutine for calculating the defocus amount for each island 21, 22, 23 shown in step #28 of FIG. 10 will be explained using FIGS. 11 to 14.

FIG. 11 shows the defocus amount of each island 21, 22, 23 for the first island 21 (step #41), the second island 22 (step #41), and the third island 23.
(Step #41).
Figures 1 to 14 show specific flowcharts of the defocus amount WAn for each island 21, 22, and 23.

Figure 12 shows the defocus amount calculation for the first island 21 (
The subroutine of step #41) is shown. As mentioned above, this first island 21 is located at the 170th island B[
1 and 270th block BL2, and a predetermined value "1K" is stored in variables DFI and DF2 that respectively store the defocus times of these blocks BL1 and BL2 (steps #51 and #52). This predetermined value "1K" is a front bin state that cannot be obtained in each block BL1 and BL2, and is the defocus amount when the focus cannot be detected in the first island 21 (hereinafter referred to as O-con). Output.

Next, a flag LCF1 indicating the 0-con state in the first island 21 is set (step #53). Then, the detection of the focal state R (ship bin state, rear bin state, in-focus state) of the first block BL1 and the defocus fiDF are extracted (step #54), and it is possible to detect the focal point from this result. For example, the flag LCF1 is reset and the obtained defocus IDF is stored in the variable DFI that stores the defocus field of the first block BL1 (step #55).
~#57), then proceed to step #58.

On the other hand, if it is determined in step #55 that focus detection is impossible, steps #56 and #57 are not performed and step #
58.

Next, step #58> detects the focus state of the second block BL2 and calculates the defocus IIIDF. If focus detection is impossible from this calculation result, the flag LCFI is
Determine if is set.

Then, when the flag LCF1 is reset, that is, when focus detection is determined to be impossible in the determination at step #55, the process moves to step #62. Also,
When the flag LCFI is set in step #60, the process moves to the defocus field calculation subroutine (FIG. 13) for the second island 22 in step #42 shown in FIG.

On the other hand, if it is determined in step #59 that focus detection is possible, the process proceeds to step #62 without performing the process in step #60.

In step #62, an inter-block defocus value ΔOF to be used in an average processing routine to be described later is determined. Next, defocus ffi DF1 and defocus ffl
Determine the size of DF2 and select the larger defocused ant,
That is, the defocus value of the subject closer to the withdrawal lens 2 (camera) is set as the defocus amount θFIS1 of the first island 21. In other words, when the defocus IDFI is larger than the defocus ffi DF2, the defocus 11 0FI is the defocus of the first island 21! lIDFIS1, conversely, defocus ffi
When DF2 is larger than defocus @OF1,
Defocus amount 2 is set as defocus tflDFls1 of first island 21 (steps #63 to #67
). Also, step #64. #65 defocus DF1
and defocus II DF2 is smaller than inter-block defocus amount ΔOF, defocus ao
f1 and defocus are averaged with DF2, and this average is calculated as the defocus flOFIS1 of the first island 21.
(Step #68). And step #66.
After completing the processing in #67 and #6B, the process moves to step #42 in FIG. 11.

Figure 13 shows defocus 1 of the second island 22? jl
llll subroutine is shown.

First, the third block BL3, the 41st block 814, the 5th block BL3,
Variables DF3, DF4, and DF5 that store each defocus amount of block BL5 are set to a predetermined value.
Set I1 (steps #71 to #73),
Flag L indicating the state of low contrast at the second island 22
Set CF2 (step #74). Then, the focus state detection and defocus ffiDF of each block 8L3, BL4, and BL5 are calculated (steps #75, #79, and #83). That is, step #75
If focus detection is possible from the calculation result of the defocus amount DF of the third block BL3 by Move to #79. Conversely, if it is determined that focus detection is impossible, step #77. Proceed to step #79 without performing the process in #78. Defocus flDF of 410th Tsuku BL4
Similarly, if focus detection is possible from the calculation result in step #79, the flag LCF2 is reset and the defocus IDF is stored in the variable DF4 (steps #80 to #
82), proceed to step #83. Conversely, if it is determined that focus detection is impossible, the process proceeds to step #83 without performing steps #81 and #82.

Similarly to the defocus lfiDF of the fifth block BL5, if focus detection is possible from the calculation result of step #83, the flag LCF2 is reset and the defocus IDF
is stored in variable F5 (steps #84 to #86),
The process moves to step #87. Conversely, if it is determined that focus detection is impossible, the process proceeds to step #87 without performing steps #85 and #86.

In step #87, it is determined whether the low contrast flag LCF2 has been hit. And flag LCF
2 is not set, i.e. step #7
6. When focus detection is determined to be impossible in each of the determinations in #80 and #84, an inter-block defocus amount (average processing width) ΔDF to be used in an average processing routine to be described later is determined (step #88). Next, each block BL
3, BL4, BL5 each defocus amount DF3
, DF4, and DF5 are determined, and the largest defocus lfi}IAXDF is extracted (step #89). Then, if there is no other block smaller than the average processing width ΔDF, the defocus II
Defocus ID of the second island 22 with HAXDF
Step #90 as FIs2. #91), if there is one or more other blocks smaller than the average processing width ΔDF, the defocus HAXDF and the average processing width Δ
Average is performed only with the defocus amounts of other blocks smaller than OF (average processing), and this average value is set as defocus l[lFIs2 of the second island 22 (step #92). Then, step #91, After completing the process in #92, the defocus calculation subroutine for the third island 23 in step #43 shown in FIG. 11 (FIG. 14)
to move to.

Furthermore, when it is determined in step #87 that the flag LCF2 is set, fST1i is re-processed from every third difference data to every seventh difference data in order to focus on the subject consisting of low frequency components (step #87). #93). That is, for example, when looking at pixel data, 1. Sky 2. ..., party n, ..., the difference data for every third party is d[)
n -Qt-Q5, ... Q5-Qta. ...,
fln-Qn+*. ...becomes... Seven again? The difference data is dQm =Qt-(1g....,Qm-Q
Work +8,... This difference data dD every 7th
m is obtained by taking the sum of every third difference data dDn. In other words, the difference data for every 7th position is d[)m - dD+◆dDs. ..., dD city + d[
)m+4,...-Q1-1! s +Q5 -419
．． −． Qn-4-an +Qn-Qn+4, -
...=Q1-Q9. −． Qn-<-Qn4<. −=
Tomi Q1-Qta.・・・． Q1 -Q+! +8.
...becomes... However, n=I+4.

Furthermore, the sum of adjacent difference data dDa is calculated to create a new data string dD! +(m)=dDI +d■m+1
is calculated and used to perform focus detection in the sixth block BL6 to detect focal ant and defocus ffiD
To calculate F, step #94), if focus detection is possible, reset the flag LCF2 and start the sixth block BL6.
The defocus IL DF6 of the second island 22 is set as the defocus IDFIs2 of the second island 22, and the process moves to Step #43 (Steps #95 to #97). On the other hand, Step #9
If focus detection is not possible in step #5, focus detection is performed in the seventh block BL7, detection of the focus state and calculation of defocus suspension DF (step #98), and if focus detection is possible (step #98) step #99), returns to step #96, resets the flag LCr2, and changes the defocus suspension of the seventh block BL7 to the defocus ffi of the second island 22.
As OFIS2, the process moves to step #43.

On the other hand, if focus detection is not possible in step #99, the eighth
Focus detection is performed in block BL8, and the focus state is detected and the defocus amount DF is calculated (step #100).
, if focus detection is possible 《Step #1 01)
, returns to step #96, resets the flag LCF2, sets the defocus area of the eighth block BL8 as the defocus area DFIS2 of the second island 22, and proceeds to step #43. On the other hand, if focus detection is not possible in step #101, step #96. The process proceeds to step #43 without performing the process in #97.

FIG. 14 shows the calculation of the defocus amount of the third island 23 (
The subroutine of step #43) is shown.

First, each defocus of the 9th block BL9 and the 10th block BL10 is a variable OF9.0F that stores .
The predetermined value II K #l is stored in the memory 10 (steps #111 and #112). Next, the flag 10 indicating the low contrast state at the third island 23 is set to ``3'' (step #1 13). Then, the focus state detection and defocus DF of the ninth block 819 are calculated (step #114), and if focus detection is possible, flag l.
cF3 is reset, and the obtained defocus ffiDF is stored in the defocus ffiDF9 of the ninth book BL9 (steps #115 to #117). On the other hand, if it is determined in step #115 that focus detection is impossible, step #116. Step #11 without performing the process #117
Move to 8.

Next, detect the focus state of the 10th block BLIO and calculate the defocus WiDF <<Step #. 118)
, If focus detection is impossible from this calculation result, flag L is set.
Determine whether CF3 is set. Then, when the flag LCF3 has been reset, that is, when focus detection is determined to be impossible in the determination at step #115, the process moves to step #122. If the flag LCF3 is set, the process moves to the exposure subroutine of step #29 shown in FIG. 10 (steps #119 and #120). Meanwhile, step #1
If it is determined in step #19 that focus detection is possible, step #12
The process moves to step #122 without performing the 0 process.

In step #122, an inter-block defocus value ΔDF for an average processing routine to be described later is determined. Next, the magnitude of the defocus It DF9 and the defocus ffiDF10 is determined, and the larger defocus field is set as the defocus fi DFIS3 of the third island 23 (steps #123 to #127). Also, step #1 2
4. #1 25 defocus ffiO "If the difference between 9 and defocus I DEIO is smaller than the average processing width ΔDF, defocus amount DF9 and defocus li
DFIO is averaged and this average value is set as the defocus fiDFIS3 of the third island 23 (step #
128>. And step #1 26. #1 27,
#1 After completing the process of 28, step #2 in Figure 10
Move to 9.

Next, the exposure calculation subroutine shown in step #29 of FIG. 10 will be explained using FIG. 15.

First, the illff detection circuit 29 detects the open Xi degree value {Avex+l!} corresponding to the brightness of the subject 8. ! ) BVO is input to the microcomputer 26 (step #131).

Subsequently, film sensitivity 1iti (Avex-Hani) Sv corresponding to the film sensitivity is input from the film sensitivity reading circuit 30 to the microcomputer 26 (step #132). Next, from the sum of these open aperture tli rU fIB vO, film sensitivity msv, and open aperture inAvO which has been input into the microcomputer 26 in advance in step #27 of FIG. 10, the exposure (aEV (EV -3VO4-SV +A
VO) (step #133).

Next, the control aperture mAV and shutter speed TV are determined based on the exposure 1iaEV (step #134).
After that, the process moves to step #30 shown in FIG.

Next, the carrier lens 2 shown in step #32 of FIG.
The process of calculating drive 1 will be explained. In the process of step #32, patterns are divided into how the subject is distributed from each defocus amount of each island 21, 22, 23, and the optimum defocus amount calculation procedure is selected for each pattern. In this way, the optimum driving amount of the projection lens 2 is obtained. Here, the means for selecting the calculation procedure will be briefly explained.

First, it is determined whether the mode is FA mode or AF mode. In the case of FA mode, if the distance measurement of the second island 22 is performed first, and the second island 22 is capable of distance measurement,
The driving amount of the Oriaki lens 2 is determined based on the defocus IDFIS2 of the second island 22, and the second island 2
2, the amount of drive of the L shadow lens 2 is determined based on the defocusing distance of the nearest island.

In other words, in FA mode, shots are often taken with a stationary subject in the center, and if the amount of defocus is calculated based on distance measurement over a wide range, it becomes unclear which island is selected and displayed. Therefore, the defocus lDF of the second island 22 performs distance measurement in the center of the play screen.
We decided to give priority to Is2.

On the other hand, in the case of AF mode, each island 21.22
．． When any one of the 23 subjects 8 can be detected in focus, the defocus of the nearest island, that is, the island whose defocus bottle is a size,
Based on the focal length data of the projection lens 2 and the distance to the subject, Ili! Calculate the prize magnification and calculate this performance IiI
The calculation procedure for defocusing was changed depending on the Song Dynasty.

That is, basically, if the m-photo magnification is large, it is assumed that the main subject always exists in the center of the decoy image, and the defocus lfiDFIs2 of the second island 22 is invaded.

In addition, if the carrying magnification is small, the VPL shadow will include the clear sky, and the dispersion of the distance distribution to the subject will be large.
Furthermore, since the main subject is often located close to the camera, priority is given to the closer side of the distance distribution. FIG. 16 shows an example of a chain that serves as a standard for determining the projection magnification and a procedure for selecting a calculation means based on this value.

That is, for example, in the case of the AF mode, the calculation means is selected with the focal length 111f of the photographic lens 2 at 35IluI. If the focal length 111f is larger than 35 am and the magnification βdr of the nearest island is smaller than a predetermined magnification βH (for example, the magnification “$1/25”), based on the fear of defocus of the nearest island, Determine the driving force vJm of the carrier lens 2.

On the other hand, when the carrying magnification βd exceeds the predetermined magnification βH, the second island 22 is defocused! Priority is given to tDF1s2, and if distance measurement is not possible for the second island 22, the driving amount of the photographing lens 2 is determined based on the defocus amount of the nearest island.

Furthermore, if the focal length @1 is less than 35 am, the driving position of the brightening lens 2 is determined based on the defocus output of the nearest island. This is because as the focal length f becomes shorter, the depth of field becomes deeper, so even if you focus on the subject on the nearest island in the distance distribution, objects detected on other islands will be within the depth of field to a considerable extent. This is because it can be included in

In addition, in the case of FA mode, priority is given to the defocus IDEls2 of the second island 22 regardless of the focal length 111f, and if distance measurement is not possible for the button 2 island 22, it is based on the defocus degree of the nearest island. Then, the drive point of the decoy lens 2 is determined.

Here, the above-mentioned means for calculating the imaging magnification βdf will be explained.

This I shadow magnification βdf is expressed by the following formula from the focal length lIl [If and the subject distance X from the camera.

βdf- f/x Since the data of the focal length wif is input from @shadow lens 2, when the object distance wix is calculated, the focal length wif is calculated as follows:
f is calculated. Further, this object distance X can be determined using the defocus amount DFx from the infinity position of the photographing lens 2 to the object position 1d as shown in the following equation.

x-f2/DFx However, the m-shadow lens 2 is not a single thin ideal lens, but has principal points at the front and back, and the principal points differ depending on the change in focal length, so from the above equation, the subject distance It is required as.

On the other hand, the defocusing fear DFo from the infinity position to the current position of the IN photo lens 2 is determined by the rotational fear (number) of the lens drive motor 33 stored in the counter inside the microcomputer 26.
It is determined from the number of pulses corresponding to N, and the relationship is as shown in the following equation.

N-k-DF. However, the value of the coefficient k is determined based on the number of pulses and the like.

From the above equation, the defocus IOFo is DFo -N/k. Then, the defocus flDF from the current position of the projection lens 2 to the subject position is DFx −DFo
+ [) F. From these formulas, the subject distance X is x-f'/
DFx-f2/ (N/k+DF) Therefore, the imaging magnification βdf is βdf-f/x- (N/k+DF)/f.

In addition to the above formula, the Zuisho magnification βIH is the driving amount ΔN〈ΔN-DF-
k), it can also be obtained as βdr−(N+ΔN>/f−k).

Next, regarding the subroutine that performs the averaging process, the 70-diagram of the second island 22 (step #88 in FIG.
．． #92) will be explained as an example.

Average step #88 in Figure 13 1! I! Radiation ΔD is determined according to the subroutine shown in FIG.
(Step #141).

That is, when the previous averaging process is performed, the flag lF2
is set. Then, if the averaging process was performed last time, the coefficient k1 is set to "1.5", and if the previous averaging process was not performed, the coefficient k1 is set to "1" (steps #142, #143). .The reason for setting the coefficient k1 is
In order to prevent averaging processing from being performed or not performed due to variations in distance measurement values, if -m averaging processing is performed, the averaging processing width may be widened and averaging processing may be performed from the second time onwards. (This is to increase the probability).

Next, the shooting magnification β (H) detected during the previous distance measurement is determined, and if the Ill type magnification βdf is “1/20” or more, the coefficient k2 is set to “1”, and the four-shot magnification βdf is is “1”
/20" to "1/50", the coefficient k2 is set to "0.
5", and if the lI! award magnification βdf is less than "1/50", the coefficient k2 is set to "0" (step #14
5 to #149), the process moves to step #150. The margin for setting the coefficient k2 is lI! This is because when the shadow magnification βd' is high, there is a high possibility that the same subject will occupy multiple blocks within the same island.

Next, in step #150, the aperture implantation FNo.
．． The reference average processing width ΔDFI is set based on the following. In other words, the aperture @FNo. The depth of focus δ, which is obtained by multiplying by the allowable diameter of the circle of confusion ε, is set as the reference average processing width ΔDFI for preserving the resolution of the photographed image.

Then, by applying the coefficient k1 and the coefficient k2 to the reference average processing width ΔDFI, the average processing width ΔDF is determined, and the flag 12 is reset (step #151). The process moves to step #89 shown in FIG.

In addition, the first island 21 and the third island 23 also have a flag for determining whether or not the previous averaging process was performed, similar to the flag IIllF2, and when the previous averaging process is performed, the flag ZF2 is set,
If the previous averaging process was not performed, it is reset.

Here, the third block BL3 is used as an example for the defocus amount of each block and the focus detection failure determination.
Steps #75 to #78) in the figure will be explained using FIG. 18(a).

First, data of the reference part 142b in the differential A-waste range from the front bin side shift pitch of 4gl (shift pitch ``-4'') to the rear bin side shift pitch of 24 positions (shift pitch "24"). The phase of the data of the third block BL3 and the data of the reference section 142b at each shift position [fl several 3 (
I) (step #1 61 ).

This phase rMrM number H3(1) is expressed by the following formula.

1-13([)-(I K2(1)-32(5+
I) l + l K2(20)-82(24”I)
l)/2+Σ1κ2(j)-S2(4-j+1)
J+2 However, K2S. The difference data string of the tl quasi section 142a is shown, and S2 shows the difference data string of the reference section 142b.

Next, the correlation function 83(
1) with the best correlation, that is, the phase OQOQ number H
The shift ffilH (I
H-MIN(l-13(1)) ) is extracted (step #162). Next, interpolation calculation between each bit is performed using the value of each point of the correlation function 83(1) (step #16
3).

The interpolation bit XM obtained by this complementary calculation is as shown in the following formula (see Japanese Patent Laid-Open No. 60-247211).

XH − I M + (H3(IN−
1)-83(Il4+1))/[MIN{H
3 (IN-1) total 1 3 (IN.1)) - 8 3 (I
N) 1/2 The reason for performing this interpolation calculation is that if one pitch deviation is converted into a defocus error, it will be approximately 1,000 μm.
This is because distance measurement with good tllf can be performed by compensating for this pitch gap.

The thus obtained interpolation pitch XH is multiplied by a coefficient α determined by the pitch length of the optical system and the photoelectric conversion element array to convert it into defocus IDF (DF-XHα) <<Step #164). Next, the contrast (light m>value C<3>) of the data of the third block BL3 is calculated in the M1 section 142.
Find it as the sum of adjacent data of a (step #i6
5), this contrast IC<3) is expressed by the following formula.

At the same time, this interpolation value YH and contrast value C〈
Find the ratio laR(3) with 3) (step #167
).

These complements 11sillYH and the ratio IIR(3) are as shown in the following equation.

YH - }{3(IN)-1 83(IN-1)
-83(IH+1) l /2R(3)-C(3)/
YH Focus detection is possible only when both the contrast IIc(3) or the ratio f
If either fiR(3) is not satisfied,
Make focus detection impossible (low contrast judgment). That is, first, it is determined whether the focus of the third block BL3 was detectable in the previous routine processing using the detection flag NLB3 (step #168). This is to reduce the determination level when focus detection was possible last time, and to prevent the determination of whether focus detection is possible from becoming unstable for a subject whose focus detection determination level is at the very edge. That is, for a subject at the very edge of the focus detection judgment level, the judgment levels Cth and Rth are each set to a predetermined value of 111c1.
．． Set R1 (step #169). Then, in step #168, if the focus cannot be detected or the first routine processing is performed, that is, the detection flag NLB3
If it has been reset, 1&shadow magnification βtS is calculated when photographing is performed using the current projection lens 2 (step #1 70).

This seed shadow magnification βLS is calculated by the above-mentioned Iffi influence ratio β(H, that is, β+H− (N/k+OF)/f
It is obtained by substituting "O" into the defocus fiDF of .

Then, the product of this Il shadow magnification βLS and the focal length f is calculated, and this product is a predetermined value (ifif·βth (for example, 300
(in the case of an im lens, βth is 1715 or more), the determination levels Cth and Rth are each set to a predetermined value C1.
A predetermined lI greater than R1! IC4. Set R4 (
Step #1 71, #1 72). In other words, the determination levels C th and Rth are stricter than in the case of step #169.

In step #171, if the maximum local contrast ill of the third block BL3 is less than the predetermined value (if
CLth is calculated (step #1 73). Then, if the local contrast {ficLth is larger than the predetermined planting set in advance, that is, if the flag OL described later is set, a predetermined value C2 is set for the determination level cth, and if it is smaller than the predetermined value, that is, the flag OL is set. C.L.
is reset, the determination level cth is set to a predetermined value of 11.
1c3 is set (steps #174 to #176). However, the relationship for the predetermined iflG2.03 is CI <02<
It is set in advance so that 03<04.

Next, it is determined whether the flag ^FSF is set, and if it is set, the determination level Rth is set to a predetermined value R2, and if it is reset, the determination level Rth is set to a predetermined value R3 ( Step #177~
#179). However, the prescribed detective R2. The relationship of R3 is R1
It is set in advance so that <R2<R3<R4.

After predetermined values are set for the determination levels Cth and Rth, respectively (steps #169. #1 72.
#1 7B. #1 79), contrast level C(3) is greater than judgment level cth, and ratio value R(3)
is larger than the judgment level Rth, the detection flag old 13 is set, and when either the contrast i1G (3) or the ratio IR (3) is smaller than the judgment level cth or the judgment level Rth, the detection flag NIB3 is set. Reset (Steps #180-91
82). Thereafter, processing such as calculation of the defocus amount of the fourth block BL4 and determination of focus detection failure shown in step #79 and subsequent steps in FIG. 13 are performed.

Here, the reason why the determination levels cth and Rthtln are set when the value is equal to or greater than the predetermined fif·βth in step #172 will be explained.

Note that the detection flag N I. B3 sets this detection flag NLB for each island, and sets this detection flag M
The determination level may be relaxed based on LB. In other words, once a focus is detected and a large amount of defocus is detected, the il distance approaches the basic image distance due to lens driving. Therefore, the image of the reference portion itself may be shifted to the third or fourth block, for example, because the image interval is increased due to lens driving, whereas the image that was in the fourth or fifth block may be shifted to the third or fourth block. In such a case, focus detection becomes impossible in the third block. Therefore, a flag LCF indicating low contrast may be stored in a separate flag LCFN for each island, and this flag LCFN may be determined during distance measurement of each island instead of the detection flag NLB.

In other words, in the case of a long focal length lens with an extremely large lens drive range (lens extension f140as or more), the lens position must be set at high magnification to satisfy the above conditions.
When trying to detect focus on a subject with a considerable distance and low magnification when the amount of lens extension is large, in such a case, the spatial frequency component has a considerable high frequency component, and the image at the reference part 142a or reference part 142b is The interval is extremely small, and completely different images are projected on the reference portion 142a and the reference portion 142b. moreover,
Due to the low magnification, a completely different subject will be projected. In such a blurred state, the optical system passes only extremely low frequency components, so it is usually impossible to detect the focus. However, as shown in FIG. 18(b), the person A. If B is lined up, person A. The detailed data (high frequency components) for distinguishing the person A.B does not pass through the optical system. Each image of B has almost the same waveform,
There are cases where the image of person A and the pagoda of person b are erroneously determined, and it is determined that the focus can be detected.

On the other hand, when the lens position is at infinity and the magnification is low, foreground,
When attempting to detect focus on a subject with high magnification, the optical system passes only extremely low frequency components, so detailed data is not passed. However, since the magnification is high, the image interval in the reference part 142a or the reference part 142b is extremely large, and different parts of the same subject are projected on the reference part 142a and the reference part 142b. Therefore, the reference portion 142a and the reference portion 142
Since there is no possibility that a subject different from that in b is projected, the determination levels Cth and Rth are set to be stricter.

Further, in steps #161 and #165, the phase lm function port 3(I) and the contrast (flG(3)) of the third block BL3 were calculated, but as shown in FIG. BL2, BL
4, BL5. BL9 and BLIO can be similarly determined.

Next, the local contrast lI in step #173 is
The calculation of icuh will be explained. This step #17
The contrast value judgment level cth in step 3 includes noise (M sound) generated by the photoelectric conversion element array, etc. ml
C noise is superimposed. This noise l C
Although the size of the noise itself does not change, the waveform of the noise varies, so the minimum true object contrast (lfIcHIN) required for focus detection is as shown in the following formula.

C th- Ct41N + MAX (Cnois
e) However, CMIN < MAX (Cnoise
) For this reason, even though the noise flcnoise is small and focus detection is originally possible, it may be determined that focus detection is impossible because the contrast level does not exceed the determination level cth. Therefore, when the maximum amount of noise Cnoise occurs, it is predicted that noise also exists in each part of the 31st block BL3, so the contrast limit is determined for each difference data of the third block BL3 according to the following formula. .

P Σ l K(j+q)−K(j+q+1) l
≧ CHIN +MAX {Cno♂ se )・P/20 However, P is a predetermined value set in advance, and is selected from values of “20” or less.

Further, in determining the contrast limit, when the local contrast value satisfies a predetermined value, the determination level of the contrast value can be determined in the same way as when the noise is small. In other words, the means for determining the contrast limit includes a plurality of determination routines, as shown in FIGS. 20 to 22. That is, in the determination routine shown in FIG. 20, for example, a data block subdivided into 7 pieces of differential data is extracted from the third block BL3, and 6 predetermined @ CL data blocks are extracted from the third block BL3.
If the contrast is greater than or equal to thl, the determination level of the total contrast is relaxed.

In other words, this determination routine first resets the flag CL and resets the variable q <step #
191). Next, the data of the third block BL3 is converted into the difference data from data K2 (1) to K2 (8) (
7) is output, and this data block c toc is compared with a predetermined IICLth1 (steps #192 and #193). and data block c
If even the data of 1[1 in toc is greater than or equal to the predetermined planting cttht, the flag CL is set (step #194
), the contrast value judgment level is relaxed.

On the other hand, if each differential data of the data block CLOC is less than the predetermined value lCLth1, the variable q is incremented and the data block C consisting of the differential data from data K2 (2'') to K2 (9) of the 31st block BL3 is created. Extract the LOC and extract this data block c t
oc and the predetermined @CLthl (step #19
5. #193). Then, even one piece of data in the data block C LOC is equal to or greater than a predetermined 11 CLth1, or the data K2 ( 1 3
) to K2 (20) continues until the data block C (OC) is extracted (steps #192 to #1 96). As a result, if all data blocks c toc are less than the predetermined I CLthl. For example, the flag OL remains reset and the process moves to the flowchart of FIG. 18(a).

Further, in FIG. 21, the maximum value and minimum value of the data of the block are extracted, and the presence or absence of local contrast is determined from the difference between the maximum value and the minimum value.

In other words, this determination routine is calculated from the data K2(1 to 20> of the third block B[3) to the maximum value [MAX(K2(
j)}] and the minimum value [MIN(K2(j))], and extract these maximum m [MAX{K2(m] t!small1lIII[MIN(K2(m) and (D difference ct
Oc ( CIOC = MAX {K2(j)} −M
Find IN(K2(j)) (step #201
〜#203〉. Next, step #204> to reset the flag CL, the difference CLOC and the predetermined HL CLth
2 (step #205). Then, the predetermined {1
If it is 71cLth2 or more, flag C is set (step #206), and the determination level of the contrast value is relaxed. On the other hand, the difference C LOC is a predetermined 1fi CLth
If it is less than 2, the flag CL remains reset and the 18th
The process moves to the flowchart shown in FIG.

Furthermore, in FIG. 22, the presence or absence of local contrast is determined by determining whether or not there is a predetermined number or more of data greater than a predetermined level among the data in the block.

That is, this determination routine first sets the change/failure j to "1', resets the variables CL1 and CL2, and further resets the flag CL (step #211). Next, the data K2 of the third block 8L3 1) and prescribed @
Compare ctth3, and when the predetermined range is CLth3 or above, add "1'' to variable CL1, and then data κ2 (1
) is less than the predetermined value - CLth3, the variable CL2 is set to “1”.
' (steps #212 to #215). and,
The product of the variable CL1 and the variable CL2 is calculated, and this product CL
If I.CL2 is greater than or equal to the predetermined value CLth4, the flag CL is set in step #217), and the contrast level determination level is relaxed. On the other hand, lficL1・C
If L2 is less than the predetermined i1cLth4 and the predetermined IIcLth2, the variable j is incremented, and for all the data K2 (2 0 > of the third block BL3),
The processes from steps #212 to #215 are performed (steps #212 to #219). As a result, even after processing all data, the products CL1 and CL2 remain at the predetermined 1ific.
If it is less than Lth4, the flag CL remains reset and the process moves to the 70-chart in FIG. 18(a).

Next, the averaging processing routine of step #92 in FIG. 13 will be explained. This average processing routine includes several processing means, and each processing means will be explained using FIGS. 23 to 25.

In the averaging processing routine in FIG. 23, step #165. Contrast I found in #167
I! A weighted leap number W(1) is set based on IC(3) and the ratio value R(3), and this weighted leap number W(1) is used to perform a weighted average of the defocus values of each block. It has become. That is, first, variable 1 is set to "3" (step #217). And each block BL3
, BL4, BL5 each defocus fliDF3
, DF4, DF5, the difference between the largest defocus amount HAXDF and defocus ffiDF3 is calculated, and this difference is compared with the average processing width ΔDF. If this difference exceeds the average processing width ΔD, the weighting step is Set defeat W (3) to “0”. Then, increment variable fil,
Defocus L HAXDF and Defocus II DF
4 and defocus IIDF5, and compare this difference with the average processing width ΔD. If this difference exceeds the average processing width 80F, the weighted leap number W(4> and the weighted leap number Set W(5) to “0′” (Steps #222 to #22
5).

That is, average processing is performed using defocus amounts within the average processing width ΔDF among the defocus amounts DF3, DF4, and DF5 of each block BL3, BL4, and BL5. Next, weighted averaging is performed using the weighting function W(1) processed as described above, and this average value is set in the defocus bottle FIS 2 of the second island 22 (
Step #226>. In other words, the defocus lDFls2 is as shown in the following equation.

DFIS2 −(DF3・W (3)+DF4・W(
4)◆(lF5 ・W (5))/ (W (3)+
W (4)-W (5)) Then, the wide zone flag control IF2 is set (step #227). Thereafter, the process moves to the defocus calculation subroutine of step #43 in FIG.

In the average processing routine shown in FIG. 24, a plurality of blocks are combined at the maximum correlation position IM, the correlation positions 11441 before and after it, and the correlation position 2f I M-1 among the number of correlations, and the phase lIl function is recalculated, Rough re-interpolation is now performed. That is, all blocks BL3
．． BL4. If BL5 is smaller than the average processing width ΔDF (average processing target), the data K of the second island 22
2 (1 to 40) and the correlation leap number is 3,4.5 (IN). H
3,4.5 (1M-1), H3,4.5 (IH+1)
Re-ffiO, roughly re-interpolate and set this value as the defocus amount DFIs2 of the second island 22.
Step #231. #232). Also, the third block B
When L3 and the fourth block BL4 are smaller than the average processing width ΔDF, the data K2 (1 to 30) has a correlation function of 83.
4 (IM). H3,4 (IM-1). H3
．． 4(IM+1.), re-interpolation is performed, and this set is set as the defocus amount DFIS2 (step #233.9234). Furthermore, if the 470th block BL4 and the fifth block BL5 are smaller than the average processing width ΔDF, the phase m figure number 8 4.5 with data K2 (11 to 40)
(1 14). H 4.5 (l H-1), Mouth 4.
5 (I old 1), re-interpolate and set this value to defocus ffiDFIs2 (step #23
5. #236>. In addition, in step #235, the third block BL3 and the fifth block BL5 have an average processing width ΔD
If it is smaller than F, the process moves to step #232, and the wide zone flag 141F2 is set (step #237>, and then the process moves to the defocus amount calculation subroutine of step #43 in FIG. 11).

Here, step #232 described above. #234, #236
The reciprocal function H3, 4.5( I N). 83.4(
IM). The calculation formula for ports 4 and 5 (IH) is shown.

Mouth 3.4.5 (IM) - 8 3,5 (IN)
- (l K2(1)-82(5+1 14)
l + l K2(4G)-32(44+IN)
l)/2+Σ1κ2(J)-32(4+j+[H
) H3.4(IN)-(l K2(1)-32(5+
IN)l + l K2(3)-32(4+j+I
M) 14 5(IN)-(I K2(11)
-s2(15+IN)l+lK27ql)42(4+j+lH) Also, in the averaging processing routine of FIG. 25, the correlation function day (1M) of each block to be averaged is calculated. Mouth (114
-1). The numbers (IM+1) are added together, and the summation result is used to perform processing subsequent to the interpolation calculation. That is, all blocks BL3, BL4, B
When L5 is smaller than the average width ΔDF, the phase [10 function 8 3, 4.5 ( I N). mouth 3,4.5
(I N-1), G13, 4.5 (I H◆1) are calculated as shown in the formula below (Steps #241, #242)
.

H 3,4.5( I N-1) 1 to {3( I
N-1) 114 (I M-1) + 1
-1 5(IN-1) H3.4,S([1)-H3([14)+H4(IN)
+85([H)H3,4.5(IN+1)-8
3 ( I H + 1) + 8 4 ( I N + 1) ten mouths 5
(1M+1) Moreover, when the 310th block BL3 and the 4th block BL4 are smaller than the average processing width ΔDF, the correlation function 83
, 4 ([ 14). H3.4 (IN-1).
H3,4 ([M◆1) is calculated as the following formula (
Steps #243, #244). H3,4( I H-1)- 83( 1 14-
1) + 84 (I M-1) mouth 3.4 (I
H) 1 113 (IN) + 84 (IM) H3,
4 (IH+1) - 83 (IM+1) 184 (IM+1)
Furthermore, the 410th block BL4 and the 5th block BL5
is smaller than the average processing width ΔDF, the correlation function 8
4.5(IM), H4,S([14-1),
H4,5 (I H◆1》 is calculated as below formula《
Step #245. #246).

H 4.5 (IN-1) - 8 4 ( 1 14-
1)+8 5(IN-1)H4,5(114)-
84(IN)+LI5(IN)H 4,5(I
N+1)=8 4(I M+1)+
8 5(l H+1) Also, in step #245,
When the third block BL3 and the fifth block BL5 are smaller than the average processing efficiency ΔOF, the correlation function 83.5 (
IN). H3,5(IN-1). H 3,5(
I H◆1) is calculated like a thousand expressions《Step #24
7>.

Mouth 3, 5 (I M-1) Mouth 3 (1 14-1) +
8 5(IN-1)H3,5(114)-83(
IN)+85(IM)H3.5(Il4◆1)-H
3( 1 M+1) 10 mouths 5( 1
N+1) and steps #242, #244, #2
After completing the calculation of the phase f1l function in steps #46 and #247, re-compensation is performed and this value is set as the defocus amount DFIS2 (step #248). In other words, the defocus amount DFIS2 is expressed by the following formula.

DFIS2-α-! H +α・(H( IM-1
) Bite ( 1M+1)) / [ MIN(H( IN-
1). (IM+1)) - H (IN)]/2 Then, set the wide zone flag ZF2 (step #249), and then step #4 in Figure 11.
The process moves to the defocus calculation subroutine No. 3.

Next, the defocus maximum calculation subroutine for the younger six blocks BL6 in steps #93 to #95 in FIG. 13 will be explained using FIG. 26.

First, differences are taken every seventh difference data string κ2(j) and 32(j) used in blocks BL3, BL4, and BL5, respectively, and summation data strings KW(j) and SW between adjacent ones of this difference data are calculated. (j) is found (step #251). This summation data string κ old j). 31
4(j) is expressed as below using the differential data string input in step #26 of FIG.

K14 (m) - K2 (m) + K2 (1 ◆ 1) + K2 (Seagull + 4) + K2 (m ◆ 5) S old 1) -32 (+) + 82
(++1)482(+44)+32(++5) Next, find the phase nlI function mouth G(I) and shift 11M (114 −MIX(
H6(1)) ) is extracted (steps #252, #2
53). This phase l1Illll! l@mouth 6 (I) is as shown in the following formula.

口6(1)-(l κW(2)-Sl4(6◆
summer) l + l KW (34)-S old 38
+I)l)/2+Σ1 question (j)-SW(4+j+1)J
t3 Here, obtaining the phase Il1gQ number H6(1) by removing the data at both ends from the data string of the reference section 142a as in the above equation is done by using the minimum shift ffiIM' during the interpolation calculation described later.
The phase near iL [11 function mouth G (IN-1). H6 (1)
．． Instead of using only H6(II4+1), we use the correlation function 86(I N-2). H Ei(I M+2
) to also use phase III III number 8 6 ( I
H-2), reference part 142b at H6 (I H+2)
This is to correct the large deviation of the position corresponding to the data of
t).

In step #254, these correlation functions T16 (IH-
2), Mouth 6 (IM-1). H 6(I M+1
1. Find mouth 6 (l H+2). In other words, these equations become 1↓.

These correlative functions 11 6 (I M-2). H 6 (
I M-1), mouth 6 ([H+1), mouth 6 (I M+
2) to perform interpolation calculation as shown below (step #
255).

Xl4-IM+(口6(IN-2)-86(
1 M+2))/[ M IN( H 6( l
H-2). H 6( l M+2))
-M AX { 11 6 (IN-1). H6
(IN◆1)) 1/2 Add coefficient α to the interpolation bit XH
} and then defocus IDF (OF-XH ・a) at t*it6 (step #256). Next, the contrast faG(6) of the data of the sixth block BL6 is determined using the following formula (step #257).

Next is Aifl11! Find the interpolation fli Y 81 of the minimum value of I number 6 (114), and use this interpolation iQ'/81 and the contrast i [c (6) to find the ratio liIR (6) as shown in the following formula ( Step #258).

YH1=MAX(H6(IN-1).H6(IHrl
)) - (IHe(IM-2)-86
( 1 M + 2) l ) / 2R (
6)-C (6)/ (YHI-OF) Next, set a predetermined value for each of the judgment levels Cth6 and Rth6, and set the contrast IC (6) and the ratio lifiR (6).
Focus detection is enabled only when both are added to a predetermined value by m, and if either contrast filG (6) or ratio IR (6) is not satisfied, focus detection is disabled (steps #259 and #260). ).

After that, the process moves to the flowchart of FIG. 13, and the process of step #96 or step #98 is performed.

Next, regarding the means of interpolation calculation in step #256, the second
This will be explained using the example shown in FIG.

First, the data string of the reference section 142a is set to "3.2, 1.-1".
．． -2. -3" and the data string of the reference section 142b is "4".
．． 3.2.1, -1. -2. -3. -4'', the phase 1 function is ku (0) - 0.ku (-1) - 6.8 (1) -
It becomes 6. Here, noise is added to the data 1fi1 of the reference section 142b, and the data string of the reference section 142b becomes "4.3".
．． 2. O. -1. -1. -3. Surt changed to -4”,
Phase na function H(0)-2.8(-1)-5.5.8(
1)-6, and the focused point, that is, the correlation function}1(I
The influence of noise on phase III is the greatest
Q number H (114-1). Akira II to H (IN◆1) becomes relatively small. Therefore, the correlation function H(IN
) is not a regular function, without using the correlation function H(IN), we can calculate the relative deviations H (
IH-2). H (1 14-1). H (1
1481) and H (IN+2) to reduce the influence of noise.

In addition, in step #259, when a normal interpolation calculation as shown in FIG. 18(a) is performed, the offset
Supplementary @ ifl Y M1 to M AX ( H 6 ( I
p! between N-1), H 6(1)441)) and the correlation function 6(1+4). OF1, Aruiha MAX (H
6 (1 14-2). H6 (I M+2)) and M
AX(H 6(I H-1).116(eye H◆1)
}, or the ratio value R using imlOF set based on the contrast IC (6) subtracted.
Perform the calculation in (6).

〔Effect of the invention〕

The present invention operates the secondary filter means when the relative displacement of the optical image cannot be detected even by using the primary filter means, so when it is possible to detect the relative displacement of the optical image only by using the primary filter means. , relative displacement can be detected in a short time. Further, when detecting the relative displacement of the optical image using the secondary filter means, the primary filter means stops its operation, and the secondary filter means stores the data extracted by the primary filter means in a memory such as a RAM. Since the extracted frequency component data is stored, the RA
It is possible to improve the utilization efficiency of memory such as M.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a camera equipped with an automatic focus detection nail according to the present invention, Fig. 2 is a mechanical configuration diagram of the focus detection means, Fig. 3 is a diagram showing a photoelectric conversion element array, and Fig. 4 is a viewfinder. Figure 5 shows the focus detection area of the intestinal shadow screen in Figure 1.
Figure 6 is an enlarged view of the assault area corresponding to islands ~ 3rd island. FIG. 7 is a diagram illustrating the defocus range of each 70 points, and FIG. 8 is a circuit block diagram of a camera configured with an automatic focus detection device according to the present invention using a microcomputer.
Figure 9. Fig. 10 is a flowchart of the interrupt operation of the microcomputer, Figs. 11 to 14 are flowcharts showing the subroutine for calculating the defocus stage for the first to third islands, and Fig. 15 is a subroutine for the exposure lighting. 16 is a diagram explaining the procedure for selecting a defocus amount calculation means, FIG. 17 is a flowchart illustrating a subroutine for calculating the average processing width, and FIG. FIG. 18(b) is a diagram explaining the calculation of the position and the determination that the focus cannot be detected; FIG.
FIG. 19 is a diagram showing the calculation of the correlation circle and contrast set for each block, FIGS. 20 to 22 are flowcharts showing the subroutine for determining the contrast limit, and FIG.
25 to 25 are flowcharts showing the average processing routine, FIG. 26 is a flowchart showing the defocus calculation subroutine, and FIG. 27 is a diagram explaining the interpolation calculation means. 1...Automatic focus detection device, 2...Photographing lens, 3.
... Focus detection means, 4... Defocus mode determining means,
5... Lens position detection means, 6... Lens drive means, 7... IIIIII means, 8... Subject, 21.
...First island, 22...Second island, 23
...Third island, 26...Microcomputer, 27...
・Lens circuit, 28...Focus detection data output circuit, 3
4... Lens iIIJIl1 circuit, 35 -...1t
II battery, 3 6-...power supply circuit, 141a, 142
a, 143a-1Sel1 part, 14lb. 142b,1
43b...Reference part, BL1...17th lock, BL
2-...2nd push, BL3...3rd push, B
L4...4th block, BL5-...5th block,
BL9--9th block, 8LiO-10th block, SW1''/N source switch, SW2... Ooaki preparation switch, SW4... selection switch.

Claims (1)

[Claims] 1. A first-order filter means for extracting a first spatial frequency component, a first focus detection means for performing focus detection based on the extracted spatial frequency component, and a second-order filter means for performing focus detection based on the extracted spatial frequency component. a second-order filter means for extracting a spatial frequency component, a second focus detection means for performing focus detection based on the spatial frequency component extracted by the second-order filter means, and a second focus detection means for performing focus detection by the first focus detection means. An automatic focus detection device comprising: determination means for operating the secondary filter means and the second focus detection means when it is determined that the secondary filter means and the second focus detection means are disabled.