JP2000009430A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the distance information of an optical system from a defocus distribution information, even if no distance information of the optical system is directly obtained. SOLUTION: A defocus distribution measuring means for measuring 2-dimensional defocus distribution in the outside world; a storage means where a plurality of defocus distribution information at each outside world position conjugate with each focal point of an optical system is held as data in advance; and outside world position estimating means 301-311 which estimate outside world position conjugate with the focal point of a current optical system, through comparison between the defocus distribution measured by the defocus distribution measuring means and the plurality of defocus distribution information stored in the storage means; are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device having a defocus distribution measuring means for measuring a two-dimensional defocus distribution in the outside world.

[0002]

2. Description of the Related Art A technique for optically measuring a distance to an object existing in a plurality of directions is disclosed in Japanese Patent Publication No. 4-6 / 1994.
No. 78607. This is a technique of obtaining distance distribution information of an object existing in an object scene, and then estimating the existence area of a main subject in the object scene based on the distance distribution information of the object.

Here, a typical method of estimating a main subject area, which has been conventionally performed, will be described with reference to FIG.

The scene of FIG. 15A is photographed by a stereo camera using a CCD or the like. Two images with parallax obtained by a stereo camera are each mx
Divide into n blocks. Then, when a known correlation operation is performed between a signal in a certain block of one image and a signal in a corresponding block captured by the other camera, a distance to an object in a previous block is obtained according to the principle of triangulation. Can be measured. By performing this measurement for all blocks, distance distribution information including m × n blocks as shown in FIG. 15B is obtained.

Next, in order to separate the objects constituting the object scene on the screen, area division (hereinafter also referred to as grouping) is performed. When this grouping is performed, the aforementioned mx
The object space composed of n blocks is divided into regions for each object as shown in FIG. (The shaded area in the figure is the area where the reliability of the correlation operation result is judged to be low due to lack of contrast of the image signal, etc.) As a grouping method, a block constituting the object space and an adjacent block Comparing the similarity of two parameters related to the block to be performed, if the similarity is high, the same object,
If the degree of similarity is low, there is a method of determining another object.
The information used as the parameter is often a normal vector of the surface when dense distance distribution data is obtained, and is simply a distance value in the case of relatively rough distance distribution data as in this conventional example. Are used.

For example, the distance information of each block shown in FIG. 15B is compared with the distance information of two adjacent blocks, and if the difference between the distances is within a predetermined threshold value,
It is determined that "objects forming two blocks form the same object", and if the difference in distance is greater than a predetermined threshold, it is determined that "objects forming two blocks are different objects". . By performing the above-described determination between all blocks and blocks adjacent thereto, the entire screen can be divided into regions for each object, and each divided region is treated as a group representing one object be able to.

Next, the characteristics of each region (each group) constituting the photographing space are evaluated, and a group representing the main subject is determined from all the groups.

For example, in the case of FIG.
For each of the groups, characteristics such as an average distance, a width, a height of the area, and a position on the screen are calculated, and a comprehensive evaluation is performed to determine an area considered as a main subject.

Next, one focus adjustment distance is determined based on the distance information in the main subject area so that the area determined as the main subject is focused, and then the lens is driven to focus.

With respect to the above method of estimating the main subject region, a proposal for improving the accuracy of grouping has been made by the present applicant (Japanese Patent Application No. 8-325327).
According to this, the threshold value used for grouping is assumed to have a non-linear characteristic with respect to the defocus amount of the block of interest, and this non-linear characteristic is further converted to distance information of the photographing lens (focus on the current object field) (I.e., position information in the field of view conjugate with the current focus position of the photographing optical system).

[0011]

By the way, even if the distance information of the photographing lens cannot be obtained in the system, if only the defocus amount can be detected, the automatic focusing function can be realized. However, in this type of apparatus, since the distance information of the photographing lens cannot be directly obtained, it is difficult to perform the above-described grouping and to recognize the main subject in the screen.

(Object of the Invention) A first object of the present invention is to provide an optical device capable of obtaining distance information of an optical system from information of a defocus distribution even if distance information of the optical system cannot be directly obtained. It is something to offer.

A second object of the present invention is to reduce the time required for obtaining the distance information of the optical system from the information on the defocus distribution.
An object is to provide an optical device that can be shortened.

[0014]

In order to achieve the first object, the present invention has a defocus distribution measuring means for measuring a two-dimensional defocus distribution in the outside world. In the optical device, a storage unit that previously holds a plurality of pieces of defocus distribution information as data at each external position conjugate to the focal position of the optical system, and a defocus distribution measured by the defocus distribution measurement unit, and The present invention is an optical device having an external position estimating means for estimating an external position conjugate to the current focal position of the optical system by comparing with a plurality of pieces of defocus distribution information stored in the storage means.

Further, in order to achieve the second object,
The present invention according to claim 2, wherein the defocus distribution in the storage means is used for estimating an external world position conjugate with the current focus position of the optical system from the defocus distribution measured by the defocus distribution measurement means. The range of information is an optical device having an operation member for designating from outside.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments.

An embodiment of obtaining the current distance information of the photographing lens from the defocus distribution information in the object field will be described with reference to the automatic focusing function of the camera as an example.

FIG. 1 is a block diagram of basic components of a camera according to an embodiment of the present invention. In FIG. 1, reference numeral 51 denotes a defocus distribution measurement for measuring a defocus amount at an arbitrary position in an object scene. A reference numeral 52 denotes a distance information detecting circuit for obtaining distance information of the photographing lens from the defocus distribution information; a reference numeral 53 denotes a main subject for detecting an area where the main subject exists from the photographing screen using the distance information obtained from the defocus distribution information. An area detection circuit, 54 is a photographing optical system, 55 is a lens driving device that drives a lens to adjust the focus, and 56 is a focus adjustment distance determination circuit. Reference numeral 57 denotes a control device, which is actually composed of a microcomputer CPU, RAM, ROM, and the like. Among them, the defocus distribution measuring circuit 51 is embodied by a computer and an optical system for measurement, and thus is represented by straddling a dotted line.

FIG. 2 to FIG. 5 are diagrams showing a specific configuration of the camera shown in FIG.

FIG. 2 is an arrangement view of optical components of a camera for detecting the distance of the object field. In FIG. 2, 1 is a photographing lens, 8 is a field lens, 9 is a secondary imaging lens,
Is an area sensor.

Two photographing screens 1 of the area sensor 10
Light beams from different pupil positions of the photographing lens 1 are respectively guided onto 0a and 10b, and are re-imaged at an imaging magnification determined by the field lens 8 and the secondary imaging lens 9. The area sensor 10 is located at a position optically equivalent to the photographic film surface with respect to the photographic lens 1, and has a photographic screen 10a
0b has a field of view equal to a part of the photographing screen or the photographing screen.

FIG. 3 shows a layout when the detection optical system shown in FIG. 2 is suitable for a camera. In FIG. 3, reference numeral 6 denotes a quick return mirror, 18 denotes a pentaprism, and 19 denotes a pentaprism.
Is a split prism, 20 is a reflection mirror, and the other is the same as FIG. FIG. 4 is a view of the layout of FIG. 3 as viewed from above the camera.

With the above-described configuration, captured images 10a and 10b having a predetermined parallax can be obtained.

The camera having the above configuration is disclosed in detail in Japanese Patent Application No. 5-278433.

FIG. 5 is a block diagram showing a circuit configuration of a camera provided with the respective components as shown in FIG. 2, and the configuration will be described first.

In FIG. 5, PRS is the control unit 5 of FIG.
7. A camera control device corresponding to, for example, a CP
It is a one-chip microcomputer having a U (central processing unit), a ROM, a RAM, and an A / D conversion function. The control device (hereinafter referred to as a microcomputer) PRS of this camera is R
In accordance with a camera sequence program stored in the OM, a series of camera operations such as an automatic exposure control function, an automatic focus adjustment function, and film winding / rewinding are performed. Therefore, the microcomputer PRS uses the communication signals SO, S
I, SCLK, communication selection signals CKCM, CDDR, CI
Using the CC, communication is performed with a peripheral circuit in the camera body and a control device in the lens to control each circuit and lens.

SO is a data signal output from the microcomputer PRS, SI is a data signal input to the microcomputer PRS, and SCLK is a synchronous clock of the signals SO and SI.

LCM is a lens communication buffer circuit,
When the camera is in operation, power is supplied to the lens power supply terminal VL and a selection signal C from the microcomputer PRS is supplied.
When the LCM is at a high potential level (hereinafter, described as “H”, and a low potential level is described as “L”), communication between the camera and the lens is buffered.

When the microcomputer PRS sets CLCM to "H" and sends out predetermined data from the SO in synchronization with SCLK, the lens communication buffer circuit LCM transmits each of SCLK and SO via the camera-lens communication contact. The buffer signals LCK and DCL are output to the lens. At the same time, a buffer signal of the signal DLC from the lens is output to the SI, and the microcomputer PRS synchronously inputs lens data from the SI.

DDR is a detection and display circuit for various switches SWS, which is selected when the signal CDDR is "H", and is controlled by the microcomputer PRS using SO, SI and SCLK. That is, based on data sent from the microcomputer PRS, the display of the display member DSP of the camera is switched, and the on / off state of various operation members of the camera is notified to the microcomputer PRS by communication. OLC is an external liquid crystal display device located above the camera, and ILC is a viewfinder internal liquid crystal display device.

SW1 and SW2 are switches linked to a release button (not shown). The switch SW1 is turned on by pressing the first step of the release button, and subsequently the switch SW2 is turned on by pressing the second step. The microcomputer PRS performs photometry and automatic focus adjustment when the switch SW1 is turned on, and performs exposure control and subsequent film winding with the switch SW2 turned on as a trigger.

The switch SW2 is connected to the "interrupt input terminal" of the microcomputer PRS. Even when the switch SW1 is turned on, an interrupt is generated by turning on the switch SW2, and the control is immediately transferred to a predetermined interrupting program. Can be.

MTR1 is for film feeding, MTR2 is for mirror up / down and shutter spring charging,
Each is a motor, and each drive circuit MDR1, MD
R2 controls normal rotation and reverse rotation. Microcomputer PR
Signals M1F, M1R, M2F, and M2R input from S to the drive circuits MDR1 and MDR2 are motor control signals.

MG1, MG2 are magnets for starting the movement of the first and second curtains of the shutter, respectively, and are energized by signals SMG1, SMG2 and amplification transistors TR1, TR2.
Shutter control is performed by RS.

The motor drive circuits MDR1, MDR2,
Since the shutter control does not directly relate to the present invention, a detailed description is omitted.

A signal DCL input to the in-lens control circuit LPRS in synchronization with LCK is transmitted from the camera to the lens LNS.
, And the operation of the lens in response to the command is determined in advance. This in-lens control circuit LPR
S analyzes the command in accordance with a predetermined procedure, and performs operations of focus adjustment and aperture control, the operation status of each part of the lens (driving status of focus adjustment optical system, driving status of aperture, etc.) from output DLC, and various parameters. (Open F-number, focal length,
It outputs distance information such as the defocus amount versus the coefficient of the movement amount of the focus adjustment optical system, various focus correction amounts, and the like.

In this embodiment, a zoom lens is shown as an example. When a focus adjustment command is sent from a camera, a focus adjustment motor LTMR is sent to a signal KMF in accordance with the simultaneously transmitted drive amount and direction. , LMR to adjust the focus by moving the optical system in the direction of the optical axis.
The amount of movement of the optical system is monitored by a pulse signal SENCF of an encoder circuit ENCF that detects a pattern of a pulse plate that rotates in conjunction with the optical system with a photocoupler and outputs a number of pulses corresponding to the amount of movement. The coefficient is calculated by a counter in the internal control circuit LPRS, and when the predetermined movement is completed, the LPRS itself sets the signals LMF and LMR to 'L' to brake the motor LMTR.

For this reason, once the camera focus adjustment command is sent, the microcomputer PRS does not need to be involved in driving the lens at all until the driving of the lens is completed. Further, when a request from the camera is met, the contents of the counter can be sent to the camera.

When an aperture control command is sent from the camera, a well-known stepping motor DMTR for driving the aperture is driven in accordance with the number of aperture stages sent at the same time. Since the stepping motor can perform open control, it does not require an encoder for monitoring the operation.

ENCZ is an encoder circuit associated with the zoom optical system, and the in-lens control circuit LPRS receives the signal SENCZ from the encoder circuit ENCZ to detect the zoom position. Lens parameters at each zoom position are stored in the in-lens control circuit LPRS, and when a request is received from the microcomputer PRS on the camera side, a parameter corresponding to the current zoom position is sent to the camera.

The ICC is a photometric area sensor for focus detection and exposure control composed of a CCD or the like, and its driving circuit. The ICC is selected when the signal CICC is "H",
It is controlled by the microcomputer PRS using I and SCLK.

ΦV, φH and φR are read signals of the area sensor output and reset signals, and a sensor control signal is generated by a drive circuit in the ICC based on the signal from the microcomputer PRS. The sensor output is amplified after reading from the sensor unit, and is input as an output signal IMAGE to an analog input terminal of the microcomputer PRS. The microcomputer PRS converts the signal into an analog signal, and sequentially stores the digital value in a predetermined address on the RAM. Go. Using these digitally converted signals, distance distribution measurement and focus adjustment or photometry of the object scene are performed.

In FIG. 5, the camera and the lens are shown as being separate (lens can be replaced).
The present invention has no problem even if the camera and lens are integrated, and the present invention is not limited to these.

Next, a series of operations by the microcomputer PRS will be described.

FIG. 6 is a flowchart showing the flow of the entire processing, and the description will be made in accordance with the flowchart.

When the photographer presses a shutter button (not shown) or the like, the photographing process is started via step (100).

In step (101), a subroutine for measuring the defocus distribution of the scene is called.
This defocus distribution measurement will be described with reference to the flowchart of FIG. The measurement of the defocus distribution is performed by a portion of the microcomputer PRS corresponding to the defocus distribution measurement circuit 51 shown in FIG.

In step (201), a sensor image is captured. The capture of the sensor image is performed as follows.

First, the sensor is reset. More specifically, the reset operation is performed inside the ICC by setting the control signals φV, φH, and φR to “H” at the same time by the microcomputer PRS for a certain period of time. Next, an accumulation start command is sent from the microcomputer PRS to start accumulation, and later the end of accumulation is detected. Then, the control signals φV and φH are driven to output the sensor output IMAG.
E are sequentially read out, A / D converted by the microcomputer PRS and stored in the RAM, and the capture of the output signal of the sensor in step (201) is completed.

The output signal data of the two sensors is stored in RAM
They are stored in the upper predetermined areas IMG1 and IMG2.

From the next step (202) onwards, "mx
Defocus distribution information (defocus map) composed of "n" blocks (m and n are positive numbers equal to or more than 1) is created.

In step (202), variables х and у indicating the coordinates of the block are initialized, and in the next step (203), a signal necessary for the defocus calculation of the block (х, у) is stored in the RAM. Image data IMG above
1 and is copied to a predetermined address A on the RAM. In the following step (204), another signal necessary for the defocus calculation of the block ($, у) is extracted from the image data IMG2 and copied to a predetermined address B on the RAM.

In the next step (205), a known correlation operation COR (A, B) is performed on the luminance distribution signals stored at the address A and the address B, and the shift amount δ between the two image signals is calculated. calculate. In the subsequent step (206), the defocus value is calculated from the image shift amount δ using a known function f (δ), and a predetermined address D (х, у) reserved for recording the defocus distribution on the RAM. ) Stores the defocus value. Then, step (207)
In, the value of х is increased by one, and the processing target is moved to an adjacent block.

In the next step (208), x is compared with the resolution m in the x direction of the defocus map. If "x <m" is determined to be true, the process returns to step (203). The calculation and storage of the defocus value are performed on the adjacent block in the x direction in the same manner as described above. Also,
When it is determined that “x <m” is false, the process proceeds to step (209), where x is initialized and y is increased by one.

In the following step (210), the value of y is evaluated, and when it is determined that "y <n" is true, the process returns to step (203) again to start the operation for the next block sequence. When it is determined that “y <n” is false, the defocus calculation for all the blocks is completed, and the defocus distribution creating subroutine (the operation in step (101) in FIG. 6) ends.

Returning to FIG. 6, in step (102), a distance information detection subroutine for obtaining the current distance information of the photographing lens from the defocus distribution information in the object scene is called. The contents of this distance information detection subroutine will be described with reference to FIGS. 8, 9, and 10. FIG. The detection of the distance information is performed by a portion of the microcomputer PRS corresponding to the distance information detection circuit 52 of FIG.

8A to 8D show distance information detection, in fact, a photographic scene is estimated from the variance and distribution of the histogram pattern of the detected defocus, and an object field position conjugate to the current focus position of the photographic optical system, ie, This is a rough flow until the distance information of the taking lens is estimated.

First, the defocus of the object scene is detected as described above. Normally, the automatic focus detection function operates when the first step of the release switch of the camera is pressed. Next, the following defocus map is created. This is one in which the detected defocus is arranged in a two-dimensional state, that is, the distribution as it is when the object field is viewed from the finder.

Subsequently, a histogram of the detected defocus amount is created in step. This represents the distribution state of the detection result for each defocus value previously arranged in a two-dimensional map, focusing on only the defocus amount.
Then, in the following, from the dispersion state, distribution center, detection defocus limit value, and the like of the histogram created above, the field position conjugate to the focal position of the photographing optical system at the time of detection, that is, the position of the photographing lens. Perform analysis to estimate distance information. FIG. 9 shows a typical example of a histogram pattern on which this analysis is based.

As can be seen from FIG. 9, a characteristic histogram distribution is obtained for each of the assumed scene conditions (scene), that is, close-up shot, near view, middle view, and distant view, and the position of the distance ring (focus position) of the photographing lens. ing.

By comparing this with the above-described histogram, the current distance information of the photographing lens is estimated.

The estimation of the distance information as described above will be described with reference to the flowchart of FIG.

First, in step (301), a histogram of detected defocus is created as described above.

From the following step (302), M × N ways (M is the focus position (four ways) in FIG. 9)
N indicates each of the photographing scenes (four patterns) in FIG. 9, and here, a typical histogram pattern of 16 patterns is referred to.

In step (302), variables x and y indicating a pattern are initialized. Next step (3)
03), a typical histogram pattern HIS
The (x, y) distribution signal is copied on the RAM as a signal sequence A (for example, first, a typical histogram pattern of “∞” in “close-up” in FIG. 9 is copied). In the following step (304), a histogram distribution signal of the detected defocus amount is set as a signal sequence B. In the next step (305), a general correlation operation COR (A, B) is performed on the signal sequence A and the signal sequence B, and the degree of correlation Δ (x, y) between the two signal sequences is calculated. Step (306)
In, the value of x which is a distance zone variable is increased by one, and the signal sequence to be subjected to the correlation operation is represented by the following typical histogram pattern (for example, a typical histogram pattern of “several m” in “close-up” in FIG. 9). Transfer to

In the next step (307), x is compared with the distance zone decomposition number M of the histogram pattern. As a result, when it is determined that “x <M” is true, the process returns to step (303), and the calculation with the histogram distribution signal of the detected defocus amount is performed on the typical histogram pattern of the next distance zone in the same manner as described above. . Also, "x <
If “M” is determined to be false (for example, when the correlation of a typical histogram pattern of “0.5 m” in “close-up photography” in FIG. 9 has been completed), the process proceeds to step (308), where x is initialized, y is incremented by one, and the process proceeds to the next assumed shooting scene in FIG.

In step (309), the value of y
In other words, the assumed shooting scene variables are evaluated, and when it is determined that “y <N” is true, the process returns to step (303) again, and the calculation for the next typical histogram pattern is started. When “y <N” is determined to be false (for example, when correlation of a typical histogram pattern of “0.5 m” in “distant view” in FIG. 9 has been completed), all the typical histogram patterns are compared. Complete the correlation operation. Then, after all the correlation operations are completed, in step (310), the maximum value Max (Δ (x, y)) of the correlation degree Δ (x, y)
Is detected. In the next step (311), the distance information detection subroutine, that is, the step of FIG. 6, is performed by using the distance information meaning the distance zone variable x of the maximum correlation degree Δ (x, y) as the current distance information of the photographing lens. (10
The operation of 2) ends.

Therefore, when the histogram as shown in FIG. 8 is obtained, it is estimated that “distance view” in FIG. 9 has “several meters” as the distance information.

Returning to FIG. 6, in step (103), a main object area detection subroutine is called. The contents of this main subject area detection subroutine are shown in FIG.
1 will be described. The detection of the main subject area is performed by a portion of the microcomputer PRS corresponding to the main subject area detection circuit 53 in FIG.

In step (401) of FIG. 11, numbering is performed for each object (group) constituting the scene. For example, as shown in FIG. 12, when performing division processing while performing raster scanning from the upper left block of the screen as indicated by the arrow in the figure, the block G above the block of interest G (x, y)
If it is determined whether (x, y−1) and the left block G (x−1, y) are in the same group, as a result, it is determined whether all adjacent blocks are the same block. It can be carried out. At this time, the blocks on the upper side (y = 0) and the left side (x = 0) of the screen do not have the upper block and the left block, respectively, so that no processing is performed on them. Also, the result of the determination is stored in the memory G on the RAM.
Record in (0,0) to G (m-1, n-1).

First, the block of (x, y) = (0, 0) is registered as a group number “g = 1”, and if a group having a different area is detected, the number of g is increased by one to increase the block number. Group number. By this processing, for example, a shooting scene as shown in FIG. 13A is given a number for each group as shown in FIG. 13B. Since the numbering process itself is a known technique called “labeling method”, a flowchart of the entire area division is omitted.

A method of determining whether each block is the same block is described in detail in Japanese Patent Application No. 8-325327 disclosed by the present applicant, and the detailed description is omitted here. Hereinafter, how to use the current “distance information” of the imaging optical system estimated earlier will be briefly described.

Here, the determination as to whether the target block and the comparison block are the same object is made by determining whether or not the angle between the object plane formed by the conjugate position of the two blocks and the optical axis is equal to or larger than a predetermined angle. If the absolute value of this angle is larger than a predetermined threshold angle, the object is considered to be the same object because it constitutes a surface nearly perpendicular to the optical axis, and if smaller than the threshold angle, it is determined to be another object. .

However, even if the angle is constant, if the absolute distance to the object is large, the absolute distance difference between the two blocks and the conjugate position will be large. Therefore, the reference threshold value for determining whether the angle is equal to or smaller than the predetermined angle based on the difference in distance may be a value proportional to the distance to the object.

However, it is necessary to obtain the reference threshold value as a function of the detected defocus amount in the target block without using the absolute distance to the object.

Therefore, the function of the threshold value is determined based on the relationship between the absolute distance to the object, the detected data focus amount, the current focal length of the photographing optical system, and the current focal position of the photographing optical system, ie, the current “distance information”. Should be obtained.
It is possible to suppress the imbalance of region division even for objects at a short distance and a long distance.

Next, in step (402), the number of subjects detected in step (401) is
Set to num. After step (403),
The characteristics of each group constituting the shooting space are evaluated, and from these characteristics, a group representing the main subject is determined from all the groups.

In step (403), 1 is set to a variable Gcur representing the group to be operated. In the next step (404), the main subject degree S (Gcur) of the subject area of the group number Gcur is calculated. The main subject degree calculates characteristics such as an average distance, an area width, a height, and a position on a screen, and evaluates them comprehensively to determine an area considered as a main subject. For example, the following expression can be considered as the main subject degree evaluation function S (Gcur).

S (Gcur) = W ₁ × (width) × (height) + W
₂ / (distance from screen center) + W ₃ / (average distance) In the above equation, W ₁ , W ₂ , and W ₃ are weighting constants,
The distance from the center of the screen is the distance between the center of the screen and the position of the center of gravity of the area, and the average distance represents the average distance of all blocks in the area. The main subject degree is calculated for all areas, and the subject having the highest main subject degree is determined as the main subject.

In the next step (405), Gcu
Increase the value of r by one and move the operation target to the next group.
In the following step (406), the values of Gcur and Gnum are compared to check whether the operation has been completed for all groups. As a result, if “Gcur ≦ Gnum”, the calculation for all the groups has not been completed, so the flow returns to step (404) and the same operation is performed.

On the other hand, if "Gcur>Gnum", the process proceeds to step (407), where the group number having the largest value among all the calculated main subject degrees S (1) to S (Gnum) is obtained. The number of the group having the highest degree of main subject is assigned to the variable Gmain by the function MAX. Gmain
The area corresponding to the number represented by represents the main subject area.
Then, in the next step (408), a sub-routine of main subject area detection, that is, step (10) in FIG.
The operation of 3) ends.

Referring back to FIG. 6, in step (104), a focus adjustment distance determination subroutine is executed.
This is performed by a portion of the microcomputer PRS corresponding to the focus adjustment distance determination circuit 56 of FIG.

Here, a subroutine for determining a distance to be adjusted from the current main subject area, that is, a defocus amount which is actually the difference between the current distance and the adjusted distance is executed. This will be described with reference to the flowchart of FIG.

In step (501), according to the group number currently set as the main subject area,
Set the target area in the scene. First, an area is set according to the result of the main subject area detection subroutine. In the next step (502), distance information for focus adjustment is calculated from information in the previously set area. Here, since the algorithm that gives priority to the closest subject in the same subject area was adopted,
Finding the closest distance within the area. That is, the defocus amount indicating the closest distance is obtained. The following steps (50
In 3), the shortest distance is set as the final focus adjustment distance, and the focus adjustment distance determination subroutine ends.

As described above, steps (101) to (101) in FIG.
After the calculation in (104), the step (105) in FIG.
The microcomputer PRS issues a focus adjustment command to the lens LNS including the lens driving device 55 shown in FIG. 1 so that the lens is focused on the distance determined in the previous step (104). The internal control circuit LPRS controls the motor LMTR to complete the currently set focus adjustment for the main subject. Then, step (10)
In 6), the signals SMG1 and SMG2 are generated at appropriate time intervals from the microcomputer PRS to the magnets MG1 and MG2 for starting the front and rear curtains of the shutter, the exposure operation is performed, and the shooting ends. .

According to the above-described embodiment, even in a system in which distance information of the photographing lens cannot be directly obtained, the histogram information of the defocus distribution previously stored as shown in FIG. By comparing the obtained defocus distributions, it is possible to easily obtain distance information of the photographing lens, that is, a field position conjugate with the current focal position of the photographing lens.

Further, by estimating the current distance information of the photographing lens from the histogram information of the defocus distribution as described above, the threshold value for grouping the defocus values is optimized by the distance information of the photographing lens. Becomes possible.

(Correspondence between Invention and Embodiment) In the above embodiment, the defocus distribution measuring circuit 51 corresponds to the defocus distribution measuring means of the present invention, and the distance information detecting circuit 52 corresponds to the external position estimating of the present invention. The ROM in the microcomputer PRS corresponding to the means and the control circuit 57 corresponds to the storage means of the present invention.

(Modification) In the above embodiment, in order to obtain a field position conjugate with the current focal point of the photographing lens, in the example of FIG. 9, 16 correlation operations of “4 × 4” are performed. Although it was necessary to always perform it, if, for example, the user can input the fact that the shooting scene is “close-up” using an external operation member, four types of correlation calculations for only the shooting scene of “close-up” can be performed. It is possible to estimate the distance information only by performing the operation, and if the camera is used, it is possible to make the camera excellent in quick shooting.

Further, an example in which the invention is applied to a camera is described, but application to other optical devices is also possible.

[0091]

As described above, according to the present invention,
An object of the present invention is to provide an optical device that can obtain the distance information of the optical system from the information of the defocus distribution even if the distance information of the optical system cannot be directly obtained.

Further, according to the present invention, the time required for obtaining the distance information of the optical system from the information of the defocus distribution is reduced.
An optical device that can be shortened can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a basic configuration of a camera according to an embodiment of the present invention.

FIG. 2 is an arrangement diagram of an optical system of the camera according to the embodiment of the present invention.

FIG. 3 is a perspective view showing an arrangement of an optical system of the camera according to the embodiment of the present invention.

FIG. 4 is a view of the optical system of FIG. 3 as viewed from above.

FIG. 5 is a block diagram showing an internal configuration of a camera according to one embodiment of the present invention.

FIG. 6 is a flowchart showing a series of operations of the camera according to the embodiment of the present invention.

FIG. 7 is a flowchart illustrating a defocus distribution measurement operation according to an embodiment of the present invention.

FIG. 8 is an explanatory diagram up to distance information estimation according to an embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of typical histogram information.

FIG. 10 is a flowchart illustrating a distance information detecting operation according to the embodiment of the present invention.

FIG. 11 is a flowchart showing a main subject area detection operation according to one embodiment of the present invention.

FIG. 12 is an explanatory diagram illustrating a region dividing method according to an embodiment of the present invention.

FIG. 13 is an example of a result of labeling according to the embodiment of the present invention.

FIG. 14 is a flowchart illustrating a focus adjustment distance determining operation according to an embodiment of the present invention.

FIG. 15 is a diagram showing a certain shooting scene, its defocus distribution result, and a state in which groups are grouped from the result for each region characteristic.

[Explanation of symbols]

 Reference Signs List 51 Defocus distribution measurement circuit 52 Distance information detection circuit 53 Main subject area detection circuit 55 Lens drive circuit 56 Focus detection distance determination circuit 57 Control circuit PRS microcomputer LPRS In-lens control circuit LNS lens

Continued on front page F term (reference) 2F065 AA06 DD06 FF04 FF05 FF09 JJ03 JJ05 LL04 MM22 QQ31 QQ41 RR06 UU05 2H011 AA01 BA23 BB00 BB03 2H051 AA06 BA04 CE27 DA07 DA26 GB12 GB20

Claims (6)

[Claims] 1. An optical apparatus having a defocus distribution measuring means for measuring a two-dimensional defocus distribution in the outside world, wherein a plurality of pieces of defocus distribution information at each outside world position conjugate to the focal position of the optical system are used as data. The storage means held in advance, and the comparison between the defocus distribution measured by the defocus distribution measurement means and a plurality of pieces of defocus distribution information stored in the storage means, the current focus position of the optical system and the conjugate An optical position estimating means for estimating an external position. 2. A defocus distribution information range in said storage means, which is used when estimating an external position conjugate with a current focus position of an optical system from a defocus distribution measured by said defocus distribution measurement means. 2. The optical device according to claim 1, further comprising an operation member for instructing from outside. 3. The external world position estimating means creates a histogram from the information on the measured defocus distribution,
A method of estimating an external world position conjugate with a current focus position of the optical system by comparing the distribution state and distribution state of the histogram with a plurality of pieces of defocus distribution information stored in the storage unit. 2. The optical device according to 1. 4. The method according to claim 1, wherein said external position estimating means estimates the position.
Environment recognition for recognizing the environment by dividing the observation plane into regions for each object using information on the external position conjugate to the current focal position of the optical system and the defocus distribution measured by the defocus distribution measuring means. 2. The optical device according to claim 1, further comprising means. 5. The optical device according to claim 4, wherein the environment recognizing means recognizes an area where the main object exists in the observation plane. 6. The optical device according to claim 1, wherein the external position conjugate to the focal position of the optical system is distance information of the optical system.