JP3352453B2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera using a silver halide film or a video camera or an image pickup apparatus cooperating with industrial equipment, and more particularly to detecting an operator's line of sight and adjusting focus on an object to which the line of sight is directed. It relates to a camera to be obtained (including a camera body).

[0002]

2. Description of the Related Art Conventional automatic cameras are provided with a so-called one-shot mode and a servo mode, which are selectively used depending on the movement of an object. For example, the one-shot mode is a mode mainly used for a still subject, in which the lens driving is inhibited after focusing once (AF lock state), and framing is performed thereafter if necessary. On the other hand, the servo mode is a mode mainly used for a moving subject, in which a continuous lens drive is performed following a change in the subject distance, and the focus can be adjusted in accordance with the movement of the subject.

There is also a camera having a function of detecting a line of sight of a photographer and selecting a focus detection area in accordance with the line of sight. According to such a camera, it is possible to focus on an intended subject without performing an AF lock operation, and even when the photographer is unfamiliar with the camera, a photograph can be taken without worrying about focusing. It became so.

[0004] When a moving subject is to be photographed,
Since the subject is not always in the center of the field, it is necessary to increase the framing flexibility. In order to increase the degree of freedom of framing, it is sufficient to increase the number of focus detection areas. By detecting the line of sight, an intended one can be easily selected from a number of focus detection areas.

In some cases, the setting can be automatically changed from the one-shot mode to the servo mode. Even in the one-shot mode, the focus detection information of the subject is observed, and when the movement of the subject is detected, the function automatically changes the setting to the servo mode.

[0006]

Since the subject moves in the servo mode, it is necessary to accurately detect the focus in order to drive the lens following the movement of the subject. The gaze position is detected. By detecting the line-of-sight position, the focus detection area intended by the photographer can be easily selected, that is, control can be performed that accurately follows the subject.

On the other hand, in the one-shot mode, the subject is almost always stationary, and once focused, the focus rarely changes thereafter. Therefore, if focus detection using the same line of sight as in the servo mode is repeated, focus detection may be performed on an unintended part in some cases, and the focus may deviate from the intended subject.

However, if focus detection is suppressed after focusing in the one-shot mode, the function of automatically switching from the one-shot mode to the servo mode cannot be effectively operated.

Therefore, in the one-shot mode, the focus detection can be performed without inadvertently selecting the focus detection area based on the line of sight detection result after focusing, so that it can respond to the movement of the subject. while a function of switching the photographing mode Te also an object to provide a camera that does not change the focal position in the non-prepared. In this application,
The camera to which the taking lens is fixed, the camera to which the taking lens is attached / detached, and the so-called camera body from which the taking lens is detached are all referred to as a camera in order to avoid complication of words.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a lens control means for controlling the focus adjustment of a lens by driving a lens, and a line of sight for detecting line-of-sight position information of an observer's eyeball. a detecting means, a focus detection means for performing a selecting means for selecting a point detection area focus on the basis of the viewpoint position information of the focus detection area there are a plurality in the photographic interface, the focus detection in one of the focus detection area A servo mode for following and correcting a change in the image plane position due to a change in the distance to the subject, and a lens drive for focusing thereafter after the focus detection unit detects that the object is in focus. and a one-shot mode to prohibit, the one-shot mode
After detecting that the camera is in focus with
A camera switching to the servo mode from the one-shot mode according to the focus detection result of the focus detection area Rukoto is detected, the focus in the one-shot mode
After detecting that the vehicle is in the state, the visual line detecting means performs visual recognition.
The focus detection means is in focus without detecting line position information
Focus detection in the focus detection area where
And returns to the servo mode according to the focus detection result.
When switched, the line-of-sight detection means detects line-of-sight position information.
And the focus detecting means selects the position based on the line-of-sight position information.
A camera is provided which performs focus detection in a selected focus detection area .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 11 are flowcharts for explaining the operation of the apparatus, and FIG. 12 is provided with a gaze direction detecting apparatus. 13 to 16 are diagrams illustrating a method of detecting a line-of-sight direction. 17 to 20 are diagrams for explaining the configuration of the focus detection device, and FIG. 24 is a diagram mainly showing an electric system of the camera.

First, in FIG. 12, reference numeral 4 denotes a camera body of a single-lens reflex camera, and reference numeral 5 denotes a lens barrel, which is detachably or fixedly mounted on the camera body 4. Reference numeral 1 schematically shows a photographing lens, which is housed in a lens barrel 5 and is moved in the optical axis X direction by the driving force of a driving motor (not shown) to execute focusing.

2 is a quick return mirror (primary mirror)
3 is a submirror, and submirror 3 is the main mirror 2.
Shall be supported by The subsequent 6 is a focus detection device, which will be described later in detail, receives light reflected by the main mirror 2 and reflected by the sub-mirror 3 while refracting and passing through the taking lens 1. On the other hand, 7 arranged on the reflected light path of the main mirror 2 is a focusing screen, 8 is a bentagonal prism, 1
Reference numeral 5 denotes an eyepiece, which constitutes a finder system. Reference numeral 9 denotes a light splitter, which is internally provided with a dichroic mirror that reflects infrared light and transmits visible light, and is provided on a finder optical path. 11 is a light emitting and receiving lens, 1
Reference numeral 2 denotes a half mirror, and 13 denotes an illumination point light source such as an LED that emits infrared light. The light source 13 is located at one focal position of a system in which the light projecting / receiving lens 11 and the eyepiece 15 are combined, and the light beam emitted from the light source 13 passes through the half mirror 12, the light projecting / receiving lens 11, the light splitter 9, and the eyepiece. The light exits from 15 as parallel light. Reference numeral 14 denotes a photoelectric converter having an element array, which is arranged at a position where the anterior segment is formed by the eyepiece lens 15 and the light projecting / receiving lens 11, and receives an eyeball image and a corneal reflection image of a light source. The members 9, 11, 12, 13, 14 and the eyepiece 15 constitute an optical system of the eye-gaze detecting device.

Next, a method of detecting the direction of the line of sight will be described with reference to FIG. In the figure, reference numeral 20 denotes a combined lens of the light projecting / receiving lens 11 and the eyepiece 15, reference numeral 22 denotes a model eye of an observer, reference numeral 21 denotes a cornea, and reference numeral 23 denotes an iris.

The infrared light emitted from the LED 13 is converted into parallel light by the lens 20 to illuminate the cornea 21 of the eyeball. At this time, a corneal reflection image d formed by a part of the infrared light reflected on the surface of the cornea 21 occurs near the iris 23 and the lens 2
The light is condensed by 0, passes through the half mirror 12, and is re-imaged at the position d 'on the photoelectric converter 14.

The light beams from the ends a and b of the iris 23 are passed through the light receiving lens 20 and the half mirror 12 to the photoelectric converter 1.
An image of the end portions a and b is formed at positions a 'and b' on the upper side 4.
When the rotation angle θ of the optical axis a of the eyeball with respect to the optical axis a of the lens 20 is small, the Z coordinates of the ends a and b of the iris 23 are Za and Z
Assuming that b, the coordinate Zc of the center position c of the iris 23 is expressed as Zc ≒ (Za + Zb) / 2.

If the Z coordinate of the corneal reflection image generation position d is Zd, and the distance between the center of curvature O of the cornea 21 and the center C of the iris 23 is OC, the rotation angle θ of the optical axis A of the eyeball is OC * sin θ関係 Zc−Zd (1) is substantially satisfied. Here, Z at the position d of the corneal reflection image
The coordinate Zd coincides with the Z coordinate Zo of O at the center of curvature of the cornea 21. Therefore, by detecting the position of each singular point (the corneal reflection image d and the end portions a and b of the iris) projected on the photoelectric converter 14, the rotation angle θ of the optical axis a of the eyeball can be obtained. At this time, equation (1) can be rewritten as β * OC * SINθ ≒ (Za ′ + Zb ′) / 2−Zd ′ (2). Here, β is a magnification determined by the distance L1 between the generation position d of the corneal reflection image, the lens 20, and the distance L0 between the lens 20 and the photoelectric converter 14.

Here, the gaze detection method using the reflected image on the cornea, the so-called Purkinje first image, has been described.
The formation of four Purkinje images, such as a reflection image of a crystalline lens, is known from the structure of the human eye. These images are also formed on the photoelectric converter 14, but other than the Purkinje first image are relatively formed. Since the light intensity is low, detection is not hindered by performing appropriate electric treatment. Also, when a person actually looks at an object, there is a deviation between the geometric optical axis of the eyeball and the visual axis (line of sight) because the macula is at the center of the field of view, but a certain amount of correction When there is no practical problem by applying the method described above, and precise correction is required, the method described in Japanese Patent Application Laid-Open No. 1-241511 can be employed.

In the arrangement shown in FIG. 13, it is assumed that the photoelectric converter 14 has one-dimensionally arranged elements in the vertical direction in the figure, and each element 14 is vertically arranged as shown in FIG. It has a strip shape whose width is several times or more the width. This makes it difficult to detect in the vertical direction, but makes it almost insensitive to vertical translation or rotation of the eyeball and simplifies signal processing. In order to obtain a similar effect, a cylindrical lens having a refractive power in a direction perpendicular to the arrangement direction of the elements may be bonded to the front surface of the photoelectric converter.

FIG. 14 illustrates a state in which a pupil image 61 and a Purkinje first image 62 are formed on the photoelectric converter.
Indicates an image of the observation eye when viewed from the front.

When the image of the observation eye is received by the photoelectric converter, FIG.
The output shown in FIG. 6 is obtained, 65 corresponds to the Prekinje first image 62, 67 and 68 correspond to the edges of the iris, and high output values on both sides correspond to the sclera (white eye).

The pupil center is obtained from the position information of the edge portions 67 and 68. In the simplest case, in the edge portion, the pixel numbers that produce an output close to the half value of the average of the iris portion 81 are i1, i
The position coordinates of the center of the pupil at 2 are given by i0 = (i1 + i2) / 2. Since the position of the Purkinje first image is determined from the maximum peak locally appearing in the pupil dark part, the relative position relationship between this position and the center of the previous pupil gives:
It is possible to know the rotation state of the eyeball, and thus the direction of the line of sight. In addition, 82 and 83 are upper and lower eyelids. Next, the configuration of the focus detection device will be described with reference to FIG. 17. The focus detection device can select one of blocks having a plurality of detection fields, respectively. FIG. 18 shows the optical action when the on-axis block is selected, and FIG. 19 shows the optical action when the off-axis block is selected.

In the figure, X is an optical axis, which corresponds to a portion after being reflected by the sub mirror 3 in FIG. Member 8 drawn with dashed lines and practice
Reference numeral 1 denotes a field mask, rectangular openings 81a, 81b, and 81c that maximize the detection field of the on-axis block.
81e, 81f, right off-axis blocks 81g, 81h, 81
i, which are arranged at or near a predetermined imaging plane of the taking lens. A movable mask 80 has a rectangular opening 80a for selecting one of an on-axis or off-axis block, and is slidably supported by a holding member (not shown) close to the field mask 81. . A driving piece 122 is fixedly provided at an end of the movable mask 80, and a female screw is formed on the driving piece. 121 is a stepping motor,
The lead screw 121a is connected to the rotation shaft of the motor. Since the lead screw 121a is screwed with the female screw of the driving piece, when the power is supplied to the stepping motor, the lead screw 121a rotates, and the driving piece 122 and the movable mask 80 move in the direction of arrow A.

Therefore, by rotating the stepping motor 121 forward and backward, the opening of the movable mask can select three positions corresponding to the three blocks of the field mask 81.

Reference numeral 82 denotes a split field lens which gives different refractive powers to the light beam passing through the on-axis block and the light beam passing through the off-axis block, and
5 is adjusted to receive a light beam in a good state. 84
Denotes a secondary imaging lens group, in which positive lenses 84a to 84d are integrally formed. Positive lenses 84a to 84d
Are three pairs: 84a and 84d, 84b and 84c,
84c and 84d.

Reference numeral 83 denotes a multi-hole mask, which has elliptical apertures corresponding to the respective positive lenses for restricting a light beam passing through the positive lenses 84a to 84d. Reference numeral 85 denotes a photoelectric conversion element, which is an array of pixels SNS3 and SNS4, and SNS5 and SN
It has S6, SNS7 and SNS8, and is enclosed in a package 86 made of transparent resin. The light beams that have passed through the upper, middle, and lower detection visual fields of each block of the visual field mask 81 are incident on the lower, middle, and upper arrays of the photoelectric conversion elements 85, respectively.

FIG. 18 shows an example in which the opening 80a of the movable mask 80 is located on the optical axis of the objective lens 1. A light beam for focus detection is formed by a movable mask opening 80a and a fixed mask opening 81.
After passing through b, the light enters the central portion 82a of the split field lens. The split field lens 82 has a conjugate relationship between the aperture mask 83 and the exit pupil plane 38 of the objective lens at the center, and in particular, the two apertures 83 of the aperture mask.
The centers of b and 83c are projected on the center of the exit pupil. Further, the luminous flux passing through the openings 83b and 83c of the porous mask is
The lens portion 84 of the re-imaging lens 84 placed behind it
b and 84c. The lenses 84b and 84c of the secondary imaging lens group place the planned imaging surface of the objective lens 1 and the light receiving surface of the photoelectric conversion element 85 in a conjugate relationship, and transfer the secondary images of the pair of objects to the light receiving surface of the photoelectric conversion element. Form on top. A back projection image of a pair of pixel rows SNS5 and SNS6 composed of a number of pixels arranged on the photoelectric conversion element on which an image of the opening 81b of the fixed mask is formed by the secondary imaging lens is a distance measurement field. Since the relative distance between the secondary images changes according to the state of image formation of the imaging lens 1 on the predetermined image formation plane,
After the photoelectric conversion, a predetermined operation is performed to determine the image forming state of the photographing lens. Ai and B in FIG.
i is an example of a signal obtained by photoelectric conversion.

The light beam incident on the focus detection system from the upper and lower openings of the field mask 81b is incident on the secondary imaging lens 84b.
84c, the pixel column SNS3 of the photoelectric conversion element
Image on SNS4, SNS7, SNS8, 2
The next image is formed. Similarly, it is possible to know the image formation state of the fixed masks 81a and 81c by using the fact that the relative distances of these images change according to the image formation state of the objective lens.

FIG. 19 shows an example in which the opening 80a of the movable mask 80 is located off the optical axis of the objective lens 1.
The light beam for focus detection passes through the movable mask opening 80a and the fixed mask opening 81e, and then is split into the divided field lens 8
2 is incident on the peripheral portion 82b. The optical axis 88 of the peripheral portion 82b of the split field lens is different from the optical axis of the objective lens, and the porous mask 83 and the exit pupil plane 38 of the objective lens 1 are conjugated with each other.
The center of 83b is projected on the center of the exit pupil. The light beam that has passed through the porous masks 83a and 83b is
Respectively enter the lens portions 84a and 84b of the photoelectric conversion element, and the object 2 is placed on the pair of pixel rows SNS5 and SNS6 of the photoelectric conversion element.
The next image is formed. Therefore, similarly to the case of the on-axis detection visual field described with reference to FIG.
5. By performing a predetermined operation on the signal photoelectrically converted by the SNS 6, the imaging state of the objective lens can be known. The upper and lower openings of the field mask 81e can be detected by photoelectrically converting images on the pixel rows SNS3, SNS4, SNS7, and SNS8.

The field masks 81g, 81h, 81i
A description of the detection system on the side is omitted because it is axially symmetric.

As described above, the pixel rows SNS3, SNS4
Are used for focus detection at the positions of the field mask openings 81d, 81a, 81g, and the pixel columns SNS5, SNS6 are provided at the positions of the openings 81e, 81b, 81h, and the pixel columns SNS7, SN.
S8 is used for focus detection at the positions of the openings 81f, 81c and 81i. Focus detection at nine positions in total is possible with three pairs of pixel rows. In any case, the back-projected image of the pixel array by the secondary imaging lens is the actual detection visual field, and if these are displayed in the finder visual field as shown in FIG. 21, it is convenient for the operator. However, the detection frames 94a to 94i may be written on one of the focusing screens in FIG. 12, or a separate liquid crystal display panel 16 may be provided adjacent above the focusing screen to display the detection field of the selected block. Is also good.

FIG. 22 is a detailed view of the multi-hole mask 83, particularly showing the positional relationship with the exit pupil image. 90 in the figure
Reference numerals a, 90b, and 90c denote images of the exit pupil of the objective lens 1 by the central portion 82a and the peripheral portions 82b and 82c of the split field lens, respectively, obtained through nine openings of the field mask 81. Inside the exit pupil image 90a,
The multi-aperture mask openings 83b and 83c are inside the exit pupil image 90b, and the multi-aperture mask openings 83a and 83b are
Inside of Oc, porous mask openings 83c and 83d are respectively placed. The multi-aperture mask openings 83b and 83c are located in a common region of the two exit pupil images, and light beams from two detection fields are selectively incident on the positions depending on the position of the movable mask 80. As described above, by configuring one mask opening to receive light beams from two detection fields,
It is possible to guide the luminous fluxes of the field masks 81a to 81i onto the photoelectric conversion element while reducing the sensor area by projecting the projected image plane of the taking lens and the photoelectric conversion element as a reduced image.

Next, FIG. 23 shows a switch for detecting whether the camera is held horizontally or vertically. If a two-dimensional area sensor is used for the photoelectric converter 14 in the eye-gaze detecting device shown in FIG. 12, if the output of the vertical side and the output of the horizontal side of the area sensor are switched according to the camera's attitude, the horizontal eye-gaze direction It is possible to detect However, since the present embodiment employs a one-dimensional sensor for the photoelectric converter 14, erroneous detection occurs when the camera is held vertically, so that the detection is stopped.

This drawing is an example of a detection switch using gravity. Reference numeral 107 denotes a rotating shaft, and a weight 108 is provided at one end of a shaft-supported lever and the friction is reduced at the other end. A micro brush 106a is provided. 109, 1
10, 111 are curved electrodes arranged on the same circle.
When the microbrush 106a is in contact with the electrode 109, a horizontal position signal is generated, and when the microbrush 106a is in contact with the electrode 110 or 111, a vertical position signal is generated.

FIG. 24 mainly shows the electric system. However, FLN
S corresponds to the lens barrel 5 in FIG. 12, and 1 corresponds to LNS.
Also, the LED corresponds to the illumination light source 13 in FIG. Further, SNS corresponds to the member 6 in FIG. 12, specifically, the optical power conversion element 85 of the focus detection device in FIG. 17, and MTR3 corresponds to the stepping motor 121 in FIG. MTR1 is a film feed motor, MTR2
Is a shutter spring winding motor. SW1 and S
W2 indicates a switch that is sequentially closed by pressing a release button (not shown), and SPC indicates a photometric sensor for exposure control. DSP indicates a display panel for displaying various information of the camera.

On the other hand, PRS is a camera control device, for example, a CPU (central processing unit), ROM, RAM,
EEPROM (Electrically Erasable Programmable RO)
M) A one-chip microcomputer having an A / D conversion function. The camera has an automatic exposure control function, an automatic focus detection function, and a film winding / rewinding function in accordance with a camera sequence program stored in a ROM. Is working. EEPROM is a type of nonvolatile memory.
Various adjustment data are written in the process. The camera control device PRS includes communication signals SO, SI, SCL
K is used to communicate with peripheral circuits and lenses and control the operation of each circuit and lens.

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

LCM is a lens communication buffer circuit,
When the camera is in operation, the lens power supply VL is supplied to the lens. When the signal CLCM from the PRS is at a high potential level, it serves as a buffer for communication between the camera and the lens.

The PRS sets the CLCM to "H", and the SCL
When predetermined data is transmitted from SO in synchronization with K, LC
M outputs buffer signals LCK and DCL of SCLK and SO to the lens via the camera / lens indirect point. At the same time, a buffer signal of the signal DLC from the lens is output to SI, and the PRS inputs lens data from SI in synchronization with SCLK.

SDR1 is a drive circuit of the line sensor device SNS for focus detection, which is selected when the signal CSDR1 is "H" and is controlled by the PRS using SO, SI, and SCLK.

The signal CK1 is a clock φ1 for driving the CCD.
1, a clock for generating φ12, and a signal IN
TEND1 is a signal for notifying the PRS that the accumulation operation has been completed.

The output signal OS1 of the SNS is the clock φ1
1, a time-series image signal synchronized with φ12, and SDR1
After being amplified by the internal amplifier circuit, the signal is output to the PRS as AOS1. The PRS inputs AOS1 from the analog input terminal, and synchronizes with ACK1 by synchronizing with CK1.
After the / D conversion, the data is sequentially stored at a predetermined address of the RAM.

AGC1 which is the output signal of SNS
Is the output of the AGC control sensor in the SNS, and SD
It is input to R1 and used for SNS accumulation control.

One of the photoelectric conversion outputs of the two images formed on the pair of sensor arrays is denoted by A (i), and the other is denoted by B.
FIG. 20 is shown as (i). In this example, the number of pixels of the sensor is 40 pixels (i = 0,..., 39).

From the image signals A (i) and B (i), the image shift amount P
Japanese Patent Application Laid-Open No. 58-142 discloses a signal processing method for detecting R.
No. 306, JP-A-59-107313, JP-A-60-101513, or JP-A-63-1
No. 8314 is disclosed.

SDR2 is a drive circuit of the line sensor device SA for line-of-sight detection, which is selected when the signal CSDR2 is "H" and is controlled by the PRS using SO, SI and SCLK.

The signal CK2 is a clock φ2 for driving the CCD.
1, a clock for generating φ22, and a signal IN
TEND2 is a signal for notifying the PRS that the accumulation operation has been completed.

The output signal OS2 of SA is clock φ21,
This is a time-series image signal synchronized with φ22, amplified by an amplifier circuit in SDR2, and output to the PRS as AOS2. The PRS inputs AOS2 from the analog input terminal, and synchronizes with ACK2 in synchronization with CK2.
After conversion, the data is sequentially stored at a predetermined address in the RAM.

AGC2 which is the output signal of SNS2
Is the output of the AGC control sensor in the SA, and SDR
2 and used for SNS accumulation control.

The LED (13 in FIG. 12) is an L for human eye illumination.
In the ED, the current is supplied to the transistor TR3 in synchronization with the accumulation of the photoelectric element SA (14 in FIG. 12), and is used for detecting the line of sight.

SPC is an exposure control photometric sensor that receives light through the taking lens, and its output SSPC is P
The signal is input to the analog input terminal of the RS and is used for automatic exposure control (AE) after A / D conversion.

DDR is a switch sense and display circuit, which is selected when the signal CDDR is "H" and
It is controlled from the PRS using O, SI, and SCLK. That is, the display of the display member DSP of the camera is switched based on the data transmitted from the PRS, and the ON / OFF state of various operation members such as a release button (not shown) (linked with the switches SW1 and SW2) and a mode setting button. The state of the gravity detection switch SWC shown in FIG.
Contact

MDR1 and MDR2 are driving circuits for the film feeding and shutter spring winding motors MTR1 and MTR2, and execute the forward / reverse rotation of the motors by signals M1F, M1R, M2F and M2R.

The MDR 3 is a movable mask 8 of the focus detection device.
Zero-movement stepping motor MTR3 (121 in FIG. 9)
The number of driving steps and the signal M3D with the signal M3P
Receives a drive direction instruction, distributes a pulse to each phase of the stepping motor, and performs current amplification for excitation.

MG1 and MG2 are magnets for starting the front and rear curtains of the shutter, respectively, and the signals SMG1, SMG2,
Electric current is supplied to the amplification transistors TR1 and TR2, and shutter control is performed by the PRS.

SW1 and SW2 are switches linked to the release button 87. SW1 is turned on when the release button 87 is pressed in the first stage, and SW2 is subsequently turned on when pressed in the second stage. The control device PRS performs photometry, line-of-sight detection, and automatic focus adjustment when SW1 is turned on, and performs exposure control and subsequent film winding with SW2 turned on as a trigger.

The switch SW2 is connected to the "interrupt input terminal" of the control device PRS, which is a microcomputer. Even when the program is executed 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 interrupt program. it can.

Note that the switch sense display circuit DD
R, the motor drive circuits MDR1 and MDR2, and the shutter control are not directly related to the present invention, and thus detailed description is omitted.

In-lens control circuit LPR in synchronization with LCK
The signal DCL input to S is transmitted from the camera to the lens FLN.
This is data of a command for S, and the operation of the lens for the command is predetermined.

The LPRS analyzes the command in accordance with a predetermined procedure, and performs operations of focus adjustment and aperture control, and output DLC.
Output various parameters of the lens (open F number, focal length, coefficient of defocus amount vs. extension amount, etc.).

The embodiment shows an example of a single lens which is fully extended. When a focus adjustment command is sent from the camera, the focus adjustment motor LMTR is controlled according to the drive amount and direction sent at the same time. Driven by the signals LMF and LMR, the optical system is moved in the optical axis direction to perform focus adjustment.
The movement amount of the optical system is determined by the pulse signal S of the encoder circuit ENC.
The signal is monitored by the ENC and is counted by the counter in the LPRS. When the predetermined movement is completed, the signals LMF, LMF
The MR is set to "L" and the motor LMTR is S-controlled.

When an aperture control command is sent from the camera, a 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.

Next, the operation of the camera will be described with reference to FIGS. FIG. 1 is a flowchart showing the entire flow of the program stored in the PRS. When the execution of the program is started by the above operation, the state of the switch SW1 which is turned on by the first stroke of the release button is detected in step (002), and when the switch SW1 is turned off, in step (005), By sending a “drive stop command” to the lens, a drive stop instruction is issued. At step (005), all the control flags set in the RAM in the PRS are cleared. The above steps (002) and (005) are repeatedly executed until the switch SW1 is turned on or the power switch is turned off. Therefore, even when the lens is being driven, when the switch SW1 is turned on, the lens stops driving. Will be. When SW1 is turned on, the process proceeds to step (003). Step (003) means a subroutine of "AE control". This "AE control"
In the subroutine, a series of camera operation controls such as photometric calculation processing, exposure control, shutter charge after exposure, and film winding are performed. The "AE control" subroutine is not directly related to the present invention, and therefore detailed description is omitted, but the outline of the function of this subroutine is as follows.

While the switch SW1 is on, the "AE control" subroutine is executed.
Display is performed. When the switch SW2 is turned on by the second stroke of the release button (not shown), the release operation is started by the interrupt processing function of the microcomputer DRS, and the aperture or the shutter time is set based on the exposure amount obtained by the above exposure control calculation. Control the
After the exposure is completed, the shutter charge and the film feeding operation are performed to complete the shooting of one frame of the film.

The camera of the embodiment of the present invention has so-called "one-shot" and "servo" as AF modes, and switches automatically according to the subject. When the AF mode is one-shot, once focus is achieved, the lens driving operation is not performed again until the switch SW1 is turned off, and release is not possible until focus is achieved.

In the case of the servo mode, the lens is driven to follow the movement of the subject even after focusing, and the release is permitted when the lens driving by the moving object prediction control described later is completed.

As described above, the release operation is performed by turning on the switch SW2. However, even when the switch SW2 is kept on even after the photographing of one frame of the film is completed, the release operation is performed.
The “AE control” returns assuming that it has been once ended. Therefore, the operation with the SW2 turned on will be described. In the case of a one-shot, the release cannot be performed until the in-focus state is reached. The focus adjustment is not performed, the next frame is shot with the same lens position,
While the switch SW2 is on, shooting is continuously performed.

In the case of the servo mode, while the switch SW2 is on, the operation is alternately repeated such as "release operation", "AF control", "release operation", "AF control".

Now, as described above, step (00)
When the “AF control” subroutine ends in 3),
The "AF control" subroutine of step (004) is executed.

FIG. 2 shows a flowchart of the "AF control" subroutine.

First, in step (108), the flag PRM is set.
The state of V is determined. PRMV is a flag related to lens control, which will be set to 1 when the lens is driven in the previous “AF control”, as described later. Since the first flow since the switch SW1 is turned on has been described, the flag PRMV is 0, and the flow shifts to step (112).

In step (112), the state of the flag SRMV is detected. However, SRMV is also a flag relating to lens control.
Go to 55). In step (155), the flag LM
VDI is detected, and since it is also 0 , step (15)
Go to 0).

In step (150), a "line-of-sight detection" subroutine is executed. This subroutine is shown in FIG. Here, the position of the line of sight of the photographer is detected. The details of this subroutine and the following subroutine will be described later.

In step (151), one block closest to the line-of-sight position among the three blocks of nine distance-measuring fields shown in FIG. 17 based on the line-of-sight detection result in accordance with the distance-measuring field-of-view range setting subroutine shown in FIG. Is selected, and the stepping motor 121 is controlled to set the opening of the movable mask 80 at a desired position.

In the next step (129), a "focus detection" subroutine is executed. The flowchart of this subroutine is shown in FIG. 5. In this subroutine, the focus state of the photographing lens is detected for three distance measurement fields. In the subsequent step (102), the AF mode is set by detecting whether the subject is moving or stationary in the subroutine shown in FIG. 3. In the first flow, AFOFLG is cleared as the one-shot mode. Returned.

In step (152), the flag AFOFL is
The state of G is detected, and since it is 0 in the first flow, the flow proceeds to step (130).

In the next step (130), a "determination" subroutine is executed. Flow chart of this subroutine is shown in FIG. The “judgment” subroutine selects one of the three distance measurement fields of view used for focus adjustment based on the result of the “focus detection” subroutine, and determines whether focusing or focus detection is impossible, and the like. If lens drive is not required, the lens drive prohibition flag LMVDI is set to 1 .

Next, in a step (131), a "display" subroutine for displaying an in-focus state or an inability to detect a focus is executed. This means that predetermined data is communicated to the display circuit DDR (FIG. 13) and displayed on the display device DSP. However, since this operation is not directly related to the present invention, further description is omitted. .

In step (132), the flag LMVDI
Detect the state of. As described above, if lens drive is not required, LMVDI is set to 1, and if LMVDI = 1 in step (132), the flow advances to step (133) to return to the "AF control" subroutine. . If the flag LMVDI is 0, the process proceeds to step (134) to detect the state of the flag LCFLG.

LCFLG is a low contrast flag set in the "focus detection" subroutine of step (129), and is set to 1 when the contrast of the image signal is lower than a predetermined value. In step (134), L
If CFLG is 0, it means that the contrast is sufficient for focus detection, and after performing "lens drive" described later in step (135), step (13)
In step 6), the lens drive flag PRMV is set to 1, and in step (137), the "AF control" subroutine is returned.

If LCFLG is 1 in step (134), it is determined that the contrast is low, and the flow proceeds to step (138).

The steps after step (138) are the first control flow of the so-called "search operation".

In step (138), the count value FCNT of the "distance ring counter" which communicates with the lens and counts the amount of movement of the focusing lens by the output pulse of the encoder associated therewith is transmitted from the in-lens control device LPRS. input. This counter is reset to 0 when the supply of the power supply VL for the lens is started, and the feeding direction is counted up,
The rewinding direction is determined as a down count.

Therefore, the count value FC of the distance ring counter
The relative position of the focus adjusting lens in the lens with respect to the optical axis direction can be known by NT.

In the next step (139), the count value FCNT is stored in the RA inside the microcomputer PRS.
This count value is stored and stored in the conversion area LPOS on M. This count value indicates the relative position of the lens at the start of the search operation. As will be described later, an object having sufficient contrast cannot be detected by the search operation. In this case, it is used to return the lens to the search start lens position.

Subsequently, in step (140), a "close-direction driving command" is transmitted to the lens, whereby the search operation is started. The lens receives this command and drives the focusing lens in the closest direction. This command does not specify the driving amount, but simply indicates the driving direction.
When the focus adjustment lens reaches the mechanical limit at the near end, the lens control circuit LPRS detects this and stops driving the lens itself. The detection of the mechanical limit position is recognized based on the time interval of the encoder pulse SENC. In step (141), the variable SRCNT and the flag SRMV are set to 1
Set to. SRCNT is a variable indicating the state of the search operation, and is 0 when the search operation is not performed, 1 when the lens is driven in the close direction, 2 when the lens is driven in the infinite direction, and is driven toward the search start lens position. Is set to 3. Here, since the lens is driven in the close direction, the variable SRCNT is set to 1. SRMV is a flag indicating that the lens drive for the search operation has been performed.

The first control of the search operation is performed in steps (138) to (141), and the "AF control" subroutine is returned in step (142).

When the "AF control" subroutine of step (003) is completed in FIG.
In step 2), the state of the switch SW1 is determined. If the switch SW1 is turned off, a "drive stop command" is sent to the lens in step (003). That is, even if a certain lens driving command is issued in the previous “AF control” subroutine, the lens driving is stopped when the switch SW1 is turned off. Then, in the next step (005), all flags are cleared.

If the switch SW1 remains on at step (002), the "AE control" subroutine of step (003) is executed, and then "AF" is again executed at step (005).
Control ”subroutine is started.

The flow of the "AF control" subroutine (FIG. 2) while the switch SW1 is on will be described below for each case.

(A) First, in the past “AF control” subroutine, instead of low contrast (flag LCFLG (1
34) is 0), the lens is driven (flag PRMV
The case where (108) is 1) will be described.

When the "AF control" subroutine is executed, the state of the flag PRMV is determined in step (108), and the flow advances to step (109). Step (1
09) communicates with the lens, and the control circuit LPR in the lens.
From S, information on the lens driving state is input. If the predetermined drive is completed and the lens has already stopped, the process proceeds to step (110) to clear the flag PRMV,
A new focus adjustment operation after step (129) is started. However, in the one-shot mode and the servo mode, the handling of the distance measurement visual field determination is different, and if the flag AFOFLG is 1 in step (156), step (15)
Go to step 0) to perform line-of-sight detection again. If it is 0, go to step (129) to perform focus detection in the same distance measurement field of view in the previous time. If the lens has not been stopped, the process proceeds to step (111) and returns to the "AF control" subroutine. That is, a new focus adjustment operation is not performed until the drive of the amount specified for the lens in the past “AF control” step (135) is completed.

(B) Next, in the previous "AF control" subroutine, with low contrast (the flag LCFLG is 1),
The case where the search operation is performed (the flag SRMV is 1) will be described.

When the "AF control" subroutine is executed, the state of the flag SRMV is detected in step (112), and the flow advances to step (113).

In step (113), information on the lens driving state is input from the lens. If the lens has already stopped, the flow proceeds to step (119), and if the lens is being driven, the flow proceeds to step (153). As described above, the search operation is performed by (a) driving the lens in the closest direction (variable SRCNT =
1) If the focusing lens reaches the mechanical limit on the near side without finding a subject with contrast during the driving of (b) and (a), the lens is driven infinitely in the future (variable SRC)
NT = 2) (c) If a subject with contrast cannot be found during the driving of (b) and the focusing lens reaches the mechanical limit on the infinity side, the lens is driven to the search start lens position in the future (variable) (SRCNT = 3).

During the search operation, the line of sight is always detected before the focus detection, and the range of the distance measurement visual field is reset each time. This is because despite the fact that the range of the field of view was set based on the line-of-sight position in the first flow, the focus detection result was low contrast, and the search operation was started. This is extremely large, indicating that the photographer may not have correctly perceived the subject, and the gaze detection result in this state has no meaning. The line of sight detection and the subroutine for setting the distance measurement visual field range in the above steps (153) and (154) are this operation.

In step (114), a "focus detection" subroutine is executed. In this subroutine, the defocus amount and the contrast of the subject are detected. Next, in step (115), the state of the low contrast flag LCFLG is determined, and if LCFLG is 1 and the contrast is low, the "AF control" subroutine is returned in step (117). That is, when focus detection is performed in the search operation, nothing is performed if the contrast is low.

If the flag LDFLG is 0 and it is determined that the contrast is not low, step (116) is performed.
Then, a “drive stop command” is sent to the lens. Next, after clearing the flag SRMV in step (118), new focus adjustment control is performed in step (129). That is, when the focus detection during the search operation is not low contrast, that is, when a contrast sufficient for focus detection is detected, the lens is stopped and the search operation is terminated (SRMV is set to 0), and the same distance measurement field of view is set. A new focus adjustment is made in the range.

If the contrast cannot be detected by the above operation (a), each time the "AF control" subroutine is executed until the focusing lens of the lens reaches the mechanical limit on the closest side, the flow goes to step (117). "AF control"
The subroutine will return.

When the lens reaches the near end, step (1)
At 13), the lens stop is detected, and the routine proceeds to step (119). Since the above case (a) has been described, the flow shifts to step (120). In the case of (b), the process proceeds from step (119) to step (123), and then proceeds to step (124). In the case of (c), the process proceeds to step (161) to end the search operation. The cases of (b) and (c) will be described later.

In step (120), the variable SRC
One is added to NT. This is because the lens has reached the near end, so that the lens is driven in the infinite direction next. In the next step (121), an "infinite direction driving command" is sent to the lens.
The search operation (b) is started. Then, in a step (122), the "AF control" subroutine is returned. (B) The control when the contrast cannot be obtained even during the operation is the same as the "AF control" as in the case (a) described above.
Each time the subroutine is executed, the process returns in step (117), and the same applies to the case where the contrast is detected.

When the focusing lens of the lens reaches the mechanical limit on the infinity side, the stop of the lens is detected in step (113), and the process proceeds to step (123) via step (119). Now the search operation is (b), so SRCN
T is 2, and from step (123) to step (12)
Go to 4). In step (124), the variable SRCN
T is incremented by one, which results in the search operation (c).

In step (125), the above-described distance ring counter value FCNT is input, and in step (126), the value of LPOS-FCNT is stored in the variable FP. Variable LPO
S stores the value of the distance ring counter at the time of the search operation, and subtracts the current counter value from this value.
Represents the distance ring counter value from the current lens position to the search start position. This FP is transferred to step (12
At 7), the lens is sent to the lens to instruct the lens to be driven by the amount of FP by the distance ring counter value. That is, the lens is driven to the search start position. And step (12)
In step 8), the "AF control" subroutine is returned. The control during the operation of the search operation (c) has been described so far (a)
This is the same as in (b).

When the focus adjustment lens reaches the search start position, the stop of the lens is detected in step (113), and the process proceeds to steps (119) and (123), and then to step (11).
After the flag SRMV is cleared in 8) and the search operation is completed, a new focus adjustment operation is started in step (129) and subsequent steps.

Next, the flow of AF control after the second time will be described. For that purpose, first, the moving object detection subroutine of step (102) will be described in detail.

FIG. 3 shows a moving object detection subroutine. This flow has a function of changing the AF mode to servo by detecting continuous movement of the subject on the image plane after focusing in the one-shot mode or when focusing is not achieved in the one-shot mode. .

First, in step (624), the state of the flag AFOFLG is detected.
Go to 23), and immediately return to the subroutine. This is to prevent returning to the one-shot mode once the servo mode is entered, and is a measure for preventing a hunting phenomenon between modes.

In step (602), it is determined whether or not focus detection is possible in the focus detection field selected in the previous flow in the focus detection in step (129) in FIG. If the process does not proceed to step (603), the process proceeds to step (620) to return the moving object detection operation to the initial state.

In the following description, the defocus amount is a value in the selected distance-measuring visual field in the previous or two-last flow.

In step (603), the defocus amount DF2 detected two times before is set to DF1, the previous defocus amount DF3 is set to DF2, and the current defocus amount DEF is set to DF1.
3 and update the data. Next step (60
In 4), it is determined whether or not focus detection has been performed three times in succession. If ACNT = 3, the flow shifts to step (607); otherwise, the flow shifts to step (605).

In step (605), the counter ACN
T is incremented by one, and the process proceeds to step (606). In the next step (605), it is determined whether or not focus detection has been performed three consecutive times again. If ACNT = 3, the flow proceeds to step (607) to perform a moving object detection operation. 623), and this subroutine is returned.

In step (607), the defocus change amount DFA from the focus detection two times before to the previous focus detection
And the defocus change amount DFB from the previous focus detection to the current focus detection is calculated.

In the next step (608), the defocus change amount DF from the previous focus detection to the current focus detection is calculated.
It is determined whether or not B is smaller than a predetermined value AD. If B is smaller than AD, the process proceeds to step (609); otherwise, the process proceeds to step (620). Therefore, when the defocus change amount DFB is larger than the predetermined value AD, it is considered that the defocus amount has changed due to the invasion of the obstacle into the field of view or the framing change, not the movement of the subject. To step (620) to reset. 0.5m as an example of the value of AD
Although a value of about m is used, if the above-described determination is performed based on the defocus change speed in consideration of the time factor, the influence of the time interval of focus detection can be removed, and more accurate determination can be performed.

In step (609), the focal length of the photographing lens is input to LF2. In the next step (610), the focal length LF1 of the photographing lens at the time of focusing is obtained.
And the change rate AIZ of the current focal length LF2 are calculated.

In step (611), step (61)
It is determined whether the focal length change rate AIZ calculated in 0) is smaller than 0.2, and if it is smaller, the process proceeds to step (612); otherwise, the process proceeds to step (620) to reset the moving object detection operation. I do. Here, when the focal length change rate is large, that is, when the photographing lens is partially focused or when zooming is greatly performed with a zoom lens or the like, the defocus amount may change due to zooming. This is to prevent the moving object from being erroneously determined.

In step (612), it is determined whether or not the values of the defocus change amounts DFA and DFB are the same. If DFA / DFB> 0, it is determined that the directions are the same, and the process proceeds to step (613). Migrate, otherwise
Proceeding to step (620), the motion detection operation is reset. This is because if the subject is moving in one direction, the direction in which the defocus amount changes is the same, so it is determined that it is a moving object, and if not, the moving object detection is redone,
Reset each parameter.

In step (613), the parameter MOVECNT for determining the moving object is counted up by one, and the flow advances to step (614).

In step (614), it is determined whether or not the defocus change amount DFB is larger than a predetermined value BD.
If it is larger than BD, proceed to step (615); otherwise, proceed to step (616). In step (615), MOVECNT is counted up by one, and the routine goes to step (616). This is because the defocus change amount DFB is larger than a predetermined value BD (for example, 0.08 mm).
This is to increase the count speed of T and to speed up the transition to servo control. If a parameter other than the defocus change amount, for example, a defocus change speed is used for this determination, the influence of the time interval of focus detection can be removed, and more accurate determination can be made.

In step (616), the currently detected defocus amount DF3 is set to a predetermined value CD (for example, 0.2 mm).
It is determined whether or not the size is larger (back focus). If the size is larger than the CD, the process proceeds to step (617); otherwise, the process proceeds to step (618). In step (617), MOVECNT is counted up by one, and step (61) is performed.
Proceed to 8). Here, if the subject at the center of the screen is in the back focus state to some extent, the count-up speed of MOVECNT is increased in order to speed up the transition to the servo control.

In step (618), it is determined whether the moving object determination parameter MOVECNT is 6 or more. If it is 6 or more, it is determined that the object is a moving object, and the flow advances to step (619).
If not, proceed to step (623) and return this subroutine.

In step (619), 1 is input to AFOFLG to set the focus detection control mode to servo control, and the subroutine is returned in step (623). Next, steps (620) to (622) are for returning the moving object detection operation to the initial state.
At 0), ACNT for counting the number of times of focus detection is reset, and then at step (621), the current focal length of the photographing lens is input to LF1. And step (6)
At 22), MOVECNT is reset, and at step (623), this subroutine is returned. This subroutine is repeated until a moving object is detected or the release switch SW2 is turned on or SW1 is turned off.

After focusing once according to the flow of FIG. 2, the AF is executed in the moving object detection subroutine described above.
Until OFLG is set to 1, 1 is set to the lens drive inhibition flag LMVDI, and step (1) is performed.
After step 55), step (129) is executed, and the moving object is detected based on the focus detection result of the same distance measurement field of view without performing the line-of-sight detection.

A moving object is detected, and AFOLFL
When 1 is set to G, the process branches at step (152) and proceeds to step (104). In step (104), the lens drive prohibition flag LMVDI is cleared, and then, in step (157), the calculation of the predictive drive of the photographing lens required for the servo operation is performed.

In step (158), the lens is driven based on the result of the prediction operation. In step (159), 1 is set to the flag PRMV, and in step 16
Return the subroutine with 0.

Next, the flow chart of the "line-of-sight detection" subroutine of FIG. 4 will be described.

First, in step (201), the vertical / horizontal detection switch SW of the camera shown in FIGS.
The posture of the camera is determined by detecting the state of C. If the result is the vertical position, the flow shifts to step (214) without performing the line-of-sight detection operation. If the position is the horizontal position, the flow shifts to step (203) to start gaze detection. In step (214), 0, which means on the optical axis, is input to the line of sight VP, and the process returns in step (213).

In step (203), the LED (FIG. 12)
13) is turned on to illuminate the eyeball, and at the same time, the accumulation of the eye-gaze detecting photoelectric conversion element SA (14 in FIG. 12) is started. Specifically, the control device PRS of FIG. 15 sends an accumulation start command to the sensor drive circuit SDR2,
Sets the clear signal CLR of the photoelectric conversion element SA to "L", and the accumulation of charges starts.

In the step (204), the input I of the PRS
The state of the NTEND2 terminal is detected, and it is checked whether the accumulation is completed. The sensor drive circuit SDR2 sets the signal INTEND2 to "L" at the same time as the accumulation starts,
The C signal SAGC2 is monitored, and when the SAGC2 reaches a predetermined level, the signal INTEND2 is set to "H", and at the same time, the charge transfer signal SH2 is set to "H" for a predetermined time to transfer the accumulated charges to the CCD unit. Have.

If the INTEND2 terminal is "H" in step (204), the process proceeds to step (205) because the accumulation is completed, and if "L", the accumulation is not completed and the process in step (204) is performed again. Execute.

At step (205), the photoelectric conversion element S
The A / D conversion of the signal AOS2 obtained by amplifying the A image signal OS2 by the sensor drive circuit SDR2 and the digital signal storage in the RAM are performed. More specifically, SDR2
Generates the CCD driving clocks φ21 and φ22 in synchronization with the clock CK2 from the PRS and supplies the clocks to the control circuit inside the SA. The SA drives the CCD unit by φ21 and φ22, and the electric charge in the CCD is the image signal. Are output in time series from the output OS2. This signal is amplified by the amplifier inside the SDR2 and then input to the analog input terminal of the PRS as AOS2. The PRS performs A / D conversion in synchronization with the clock CK2 output by itself, and
The converted digital image signals are sequentially stored at predetermined addresses in the RAM.

In step (206), the edge of the pupil is detected based on the eyeball information obtained in step (205). As mentioned above, this is done by extracting the pixels that produce an output close to half the average of the output of the iris.

In step (207), the contrast value of the image obtained during the processing in step (206) is obtained.
And the difference between the predicted pupil diameter calculated from the finder brightness corresponding to the SPC (FIG. 21) output and the detected pupil diameter, etc., to determine the reliability of the pupil diameter detection result. The predicted pupil diameter is a standard value of the pupil diameter that contracts and expands according to the brightness of the external world. That is, accumulation is performed during the jumping movement of the eyeball, and the case where the image of the pupil is unclear or the case where the decrease in the image output due to eyelashes is mistaken for the pupil is excluded. If it is determined that the reliability is sufficient, the step (20)
The process proceeds to 8), and when it is determined that the reliability is insufficient, the process proceeds to step (212).

Next, at step (208), the first Purkinje image is extracted. This is done by detecting a luminance peak appearing on the pupil or iris.

In the step (209), the contrast of the detected first Purkinje image is compared with a predetermined value to determine whether the ghost light from the glasses or the like overlaps the Purkinje image, or if the Purkinje image is half missing due to blinking, etc. Is detected, and at this time, it is determined that the reliability is insufficient, and the process branches to step (212). If the reliability is sufficient, the process proceeds to step (210).

In the following step (210), the rotation angle of the eyeball is calculated based on the equation (2).

In step (211), step (21)
The viewpoint (line) VP on the focus plate is calculated from the rotation angle of the eyeball obtained in step 0) and the default value of the finder optical system, and the subroutine is returned in step (213).

In the extraction of the first Purkinje image and the pupil edge, if it is determined that the reliability is insufficient, in the step (212), the flag VLNG indicating that the line of sight cannot be detected is set to 1 and the subroutine is executed in the step (212). Is to be returned.

Next, FIG. 11 is a flow chart showing a subroutine of "range setting of the field of view for distance measurement". This subroutine
Based on the gaze detection result, it is determined which of the three blocks having the distance measurement field is to be selected.

First, in step (902), the gaze detection disable flag VL set in the gaze detection subroutine
NG state is detected, and if it is 0, step (903)
And if it is 1, branch to step (906),
Return the subroutine. This means that when the line of sight cannot be detected, the range-finding visual field range is set to the same position as in the previous flow.

In step (903), the viewpoint VP information (distance from the optical axis) on the focus plate and a predetermined value a, for example, 1 in the case of a 35 mm camera half the viewfinder field of view.
Compare with 8 mm. If it is larger than a, it is determined that the photographer has been looking at photographing information and the like other than the subject image, and the range of the range-finding field of view is not set based on the line of sight at this time.

In step (904), a distance measurement field of view closest to the viewpoint VP is selected from three ranges.

In the step (905), the movable mask 80
Drive control of the moving stepping motor MTR3 of
Enables focus detection for a selected field of view.

FIG. 5 shows a flowchart of the "focus detection" subroutine. In steps (802) to (804), the defocus amounts DF (1) and D of the photographing lens for the upper, middle, and lower distance measurement fields in the selected block.
The contrast between F (2) and DF (3) and the image signal is calculated.

In step (805), if all the contrasts calculated in steps (802) to (804) are equal to or smaller than the predetermined value, the flow branches to step (806). If any one of the contrasts is equal to or greater than the predetermined value, the process proceeds to step (807) and returns to the subroutine.

Next, the "determination" subroutine and the "prediction calculation" subroutine will be described. These are subroutines for using the information of a plurality of ranging visual fields within the range for focus adjustment after the ranging field block is determined based on the result of the eye gaze detection, and are selectively used according to the focusing operation mode of the camera. .

First, the flowchart of the "determination" subroutine will be described with reference to FIG.

In step 701, it is determined here whether or not this is the first distance measurement calculation. Step 7 in the case of the first distance calculation
If not, the flow branches to step 704.

In step 702, communication between the lens and the FLNS is performed to input lens information into the microcomputer. Information such as focal length, close distance, sensitivity coefficient, and comb pitch is read from the lens.

Based on the information read in steps 703 and 702, the closest threshold value is calculated for each of the distance measurement fields (TH (1), TH (2), TH (3)).

These thresholds are set to different values depending on the distance measuring point. For example, TH (1) = TH (3) = 20f is set as the threshold value for the upper and lower ranging points using the focal length f of the lens at that time. The threshold value for the center is set closer to the threshold value of the upper and lower distance measurement points, and for example, TH (2) = 10f. This is in consideration of the fact that an unintended object of the photographer rarely enters the center or a short distance of the screen. Further, when it is assumed that a macro lens is in a close-up state, the threshold value is reduced by multiplying the threshold value by a certain magnification (smaller than 1).

Step 704 is to read the current lens absolute position (focus value) from the lens. If there is no information on the absolute position of the lens, the lens is once applied to the infinite end at an appropriate time such as when the power is turned on, and the movement of the lens from that point is determined. By storing in a predetermined memory, the current lens position can be obtained.

In step 714, the defocus amount DF is determined for the distance measurement field of view whose contrast is equal to or greater than the predetermined value.
(1) to DF (3) and absolute distances AD (1) to AD at which the focus of each ranging point is detected from the lens position stored in S4
Find (3). The number of absolute distance data is stored in NN.

In step 715, AD (1) to AD (1)
(3) is compared and the order of the closest distance is assigned. A in N1
The distance measuring point number of the closest distance from D (1) to AD (3) is entered, the distance measuring point number of the second distance is entered into N2, and the distance measuring point number of the furthest distance is entered into N3.

In step 724, if NN = 1, the flow branches to step (719).

In step 716, the threshold value is compared with the closest measured distance point. Step 715
Has been found, the distance measuring point number (N1) of the closest distance is obtained.
(N1) is compared. If the distance measurement distance AD (N1) is smaller than the threshold value TH (N1), the flow branches to step 717. If it is larger, the process branches to step 720.

If NN = 2, step 725 branches to step (719).

At step 720, it is determined whether or not the distance measurement distance is continuously increasing. Since the distance measuring points are numbered in order from the top, if the distances N1 to N3 are arranged in ascending order or descending order, it can be determined that the distance measuring points are continuously increasing. If it is continuously away, the process branches to step 718;
Branch to 19.

In step 717, since the near point is smaller than the threshold value, the second closest point is selected. The distance measuring point number N2 of the second distance is stored in OP.

In step 718, if the subjects are continuously arranged, the distance measuring point is set at the center (ranging point number 2). The selected ranging point number 2 is stored in the OP.

In the step 719, if no branch is made by the judgments in the steps 716 and 720, the nearest distance point is stored in the OP.

At step 721, when the selection of the selected point is completed, it is determined whether or not the selected distance measuring point is in focus. At the time of focusing, the flow branches to step 722, and when not focused, the flow branches to step 723.

At step 722, the focus flag JFF
LD is set to 1 and the subroutine is returned in step 723.

Next, the flow of the "prediction calculation" subroutine will be described with reference to FIG. FIG. 7 shows the flow of the "prediction calculation" subroutine, in which it is determined whether or not the prediction calculation is possible. If the prediction is possible, the lens driving amount is calculated in consideration of the AF time lag and the release time lag.

In step (302), it is determined whether or not a counter COUNT for determining whether data necessary for prediction has been accumulated is counted up.
In this embodiment, when distance measurement data and lens drive data are accumulated three or more times, that is, when COUNT> 2, prediction calculation can be performed, and further counting up is not required. BA step (30
Proceed to 4). If COUNT <3, COUNT is counted up in step (303), and then the process proceeds to step (304).

In step (304), data for the current prediction operation is updated. That is, the prediction calculation is performed according to (6), (7), and (2) described in JP-A-1-288816.
Since the calculation is performed based on the equations (8) and (9), the data includes the DF
2, DF1; DL2 and DL1 as the last and two-last lens drive amounts; TM2 and TM1 as the last and two-last time intervals; and expected time lag TL.
Therefore, in step (304), each time the focus detection is performed, the defocus amount DF2 obtained two times before is stored in the storage area D.
F1 and the defocus amount DL obtained last time is input to the storage area DF2, and the lens drive amount DL2 obtained two times before is converted to the image plane movement amount obtained in the storage area DL1.
The lens driving amount DL converted in the image plane movement amount obtained last time is input to the storage area DL2, and the data in each storage area is updated to the data necessary for the current prediction calculation.

In step (305), it is determined whether or not the AFP indicating the position of the used distance measuring point is "0". Here, when the AFP is “−1”, the lower distance measurement field of view, “0”
Indicates that the center ranging point is used, and "1" indicates that the upper ranging field is used. That is, in step (305), it is determined whether or not the center ranging field of view is being used. If the center ranging field of view is being used, step (30) is performed.
Go to 6), otherwise go to step (307).

In step (307), step (30)
In the same manner as in 5), it is determined whether or not the lower ranging field of view is used. If the lower ranging field of view is used, the process proceeds to step (308), and the upper ranging field is used. If so, the process proceeds to step (309).

Steps (306), (308), (30)
In 9), the defocus amount measured this time in the field of view used this time is input to the storage area DF3 in the RAM, and the data is updated. Here, in step (306), the defocus amount DFB based on the image signal of the sensor in the center distance measurement field,
In step (308), the defocus amount DFA based on the sensor image signal of the lower ranging point is input, and in step (309), the defocus amount DFC based on the image signal of the sensor of the upper ranging point is input. When the above steps are completed, the process proceeds to step (310).

In step (310), it is determined whether or not data necessary for the prediction operation has been input to each of the storage areas. As described above, the prediction calculation requires the defocus amount this time, the previous time and the previous two times and the lens driving amount last time and the previous two times,
The condition is that three or more focus adjustment operations have been performed in the past. Therefore, every time the focus adjustment operation is performed in step (303), the counter COUNT is incremented by +1.
The counter is made to count the number of times the focus adjustment operation has been performed, and it is determined whether the number of times is greater than 2, that is, whether or not the operation has been performed three or more times. If not, the process proceeds to step (312). If not possible, the process proceeds to step (319).

In the step (312), it is determined whether or not the continuity of the image plane position is determined whether the defocus amount updated this time is suitable for the prediction. If it is determined that there is continuity, the process proceeds to the step (313). Otherwise, the process proceeds to step (314). Here, the method of determining the “continuity of the image plane position” will be described later.

In step (312), it is determined that the continuity of the image plane position is not present, and when the flow proceeds to step (314), the distance measuring field used in the subroutine "change distance measuring field" is changed in this step. A detailed description of this subroutine will be described later.

In step (315), after changing the distance measurement field, it is determined whether or not the prediction is possible by ANG. If possible, the process proceeds to step (313), and if the prediction is impossible (unsuitable data). If so, the process proceeds to step (316).

In step (316), the COUNT for counting the number of times data has been accumulated is reset to temporarily stop the prediction control. And step (31)
In 7), the flag ANG of the prediction possibility determination is reset.

In the step (318), the defocus amount D of the center distance measurement field is added to the lens drive amount DL in terms of the image plane movement amount.
Enter FB. This means that once it becomes unpredictable,
The distance measurement field used when starting AF again is the center distance measurement field, but this need not be the center distance measurement field. For example, the distance measurement field selected first,
Alternatively, the ranging field used last may be used.

In the first and second distance measurements, the process shifts to step (319), and in step (319), the defocus amount DF3 updated this time is input to the lens drive amount DL in terms of the image plane movement amount.

When it is determined in step (312) that prediction is possible and the process proceeds to step (313), the expected time lag TL is calculated in step (313).
As described above, the time from the previous time to the current focus detection operation is stored in the storage area TM2, and the estimated time lag TL is assumed based on the assumption that the time required for the current focus adjustment also matches TM2. = TM2 + TR. Here, TR is a release time lag.

In the next steps (320) and (321), each of the storage areas DF1 to DF3, DL1, DL2, TM1,.
Based on the data stored in TM2, A and B representing the terms a and b in the equations (6) and (7) are obtained, and the routine proceeds to step (322).

In the step (322), the data of each storage means and the steps (313) and (32)
(9) is calculated based on the calculated values of (0) and (321), and this is calculated as the lens driving amount DL in terms of the current image plane movement amount.
Ask for.

In the next step (323), the lens drive amount DL obtained in steps (322), (318), and (319), the open F number FN of the photographing lens, and a predetermined coefficient δ (in this embodiment, 0. 035mm) product FN
δ are compared, and if DL <FN · δ, step (32)
Go to 4), otherwise return in step (325).

In step (324), the previous step (3)
23), it is determined that the lens driving amount DL is smaller than the image plane depth FN · δ, that is, it is not necessary to drive the lens,
The lens driving amount DL is set to 0, and the driving of the lens is prohibited.
As a result, unnecessary driving of the minute lens is not performed, and both of usability and power consumption can be improved. In the present embodiment, FN is the open F number of the taking lens. However, there is no problem even if this is used as the taking aperture value, and δ is not limited to 0.035 mm. When this step is completed, the next step (32
In 5), this subroutine is returned.

Next, the flow of the subroutine "change distance measuring point" will be described with reference to FIG. The figure shows the flow of the “change distance measurement field of view” subroutine. Since it is determined that the defocus amount of the selected distance measurement field of view is not suitable for the prediction control, other distance measurement points that can be predicted and controlled can be used. Is a subroutine for changing to

In step (402), it is determined by the AFP whether or not the currently used ranging field of view is the center ranging field. If the center ranging field of view is used, the process proceeds to step (403). Otherwise, step (41)
Go to 3).

In step (413), step (40)
In the same manner as in 2), it is determined whether the currently used ranging field of view is the lower ranging field of view. If the lower ranging field of view is being used, the process proceeds to step (414), and If the distance measurement field of view is used, the process proceeds to step (425).

Steps (403) to (412), (41)
4) to (423) and (425) to (434) indicate changes in the image plane position close to the previous image plane change from the defocus amount of the ranging field other than the currently used ranging field. This is to select the distance measurement field of view.

In the step (403), the image plane moving speed V1 from the distance measurement two times before to the previous distance measurement is calculated. In the next step (404), the image plane moving speed V2 from the previous distance measurement to the current distance measurement is calculated using the defocus amount DFA of the left distance measurement field of view.

In step (405), step (40)
3), the absolute value VA of the difference between V1 and V2 calculated in (404) is calculated. This is the conventional image plane moving speed V1
And the continuity of the image plane mobility V2 in the new left ranging field of view, that is, the continuity. The smaller the value of VA, the higher the continuity.

In step (406), the image plane mobility V3 from the previous distance measurement to the current distance measurement is calculated using the defocus amount DFC in the upper distance measurement field of view. Then, in step (407), VC indicating the continuity when the upper distance measurement field of view is used in the same manner as in step (405).
Is calculated.

In the next step (408), VA and VC for evaluating the continuity of image plane position change are compared, and VA <V
If C, that is, the continuity in the lower distance measurement field is higher, the process proceeds to step (411), and if not, the process proceeds to step (409).

In step (409), the defocus amount DFC of the upper distance measurement field is input to the storage area DF3 on the RAM because the upper distance measurement field has higher continuity. Then, in step (410), "1" representing the upper ranging field of view is input to the AFP representing the ranging point to be used.

In step (411), the defocus amount DFA of the lower distance measurement field is input to the storage area DF3 on the RAM because the lower distance measurement field has higher continuity. Then, in step (412), "-1" representing the lower distance measurement field of view is input to the AFP.

When the step (410) or (412) is completed, the flow shifts to the step (435). Steps (414) to (423) and (425) to (43)
Similarly, 4) is used for selecting a ranging point having high continuity by using the image plane position change from the last two times to the previous time, and the operation is the same as steps (403) to (412). Detailed description is omitted.

In step (435), it is determined whether or not the continuity of the image plane position is suitable for predictive control based on the changed defocus amount of the distance measurement field of view, and if so, the process proceeds to step (438). If not, step (43)
Go to 6).

In step (436), it is determined that the field of view is not suitable for predictive control even though the range-finding field has been changed to the most suitable point. Therefore, "1" is set to the flag ANG for temporarily suspending predictive control. input. And step (43)
In 7), "0" is input to the AFP in order to return the used distance measurement field to the center distance measurement field. Then, when this step ends, the flow shifts to the step (438), and this subroutine is returned.

In the above-described prediction calculation and ranging point change subroutine, when the continuity of the image is not recognized in step (312) with the defocus data of the ranging point used first, the ranging field is changed. The defocus data in the field of view having the highest continuity among the three distance measuring points is detected. Based on this data, the presence or absence of continuity is determined again in step (435). The prediction calculation based on the most continuous defocus data is (31
3) to (322) are continuously executed. In addition,
At this time, the AFP indicating the ranging point of the defocus data
Becomes a value corresponding to the ranging point of the data, and the subsequent focus detection is performed according to the defocus data from the changed ranging point, and the ranging point is changed. When continuity is not recognized even in step (435), ANG =
The prediction processing is temporarily stopped, and the lens is driven based on the data of the center distance measurement field.

Next, the "determination of continuity of image plane position" subroutine will be described with reference to FIG.

In step (502), an operation of (DF2 + DL1-DF1) / TM1 is performed based on the data in each storage area. This calculation is a step of calculating the average value V1 of the image plane moving speed between times t1 and t2 in FIG. The calculation in the next step (503) is a step of similarly calculating the average value V2 of the image plane moving speed between times t2 and t3. Thereafter, the process proceeds to step (504).

In step (504), step (50)
2), calculate the absolute value VA of the difference between the image plane moving speeds V1 and V2 obtained in (503), and proceed to step (505).

In step (505), step (50)
The VA obtained in 4) is compared with a preset number AX. When VA is larger than AX, it is determined that there is no continuity of the image plane position, and when VA is smaller than AX, it is determined that there is continuity.

The principle of judging presence / absence of continuity by the above flow is based on the fact that if the same object is followed, the image plane moving speed at that time also changes continuously. Therefore, the image plane moving speeds that are temporally adjacent to each other are calculated, and if this difference is small, it is assumed that the image plane moving speed is continuously changing, and it is determined that the same subject is being measured. Perform a prediction operation. On the other hand, when the change in the image plane moving speed is sufficiently large, it is considered that the image plane moving speed does not continuously change.

FIG. 10 shows a flowchart of the "lens drive" subroutine.

When this subroutine is executed, two data "S" and "PTH" are input in step (1502) by communicating with the lens. “S” is a “defocus amount vs. a coefficient of a focus adjusting lens drawn-out amount” unique to a photographing lens. For example, in the case of a single lens of a full extension type, S = 1 because the entire photographing lens is a focus adjusting lens.
In the case of a zoom lens, S changes depending on each zoom position. “PTH” is the amount of focus adjustment lens per pulse output from the encoder ENC that is interlocked with the movement of the focus adjustment lens LNS in the optical axis direction.

Therefore, the current defocus amount DEF of the photographing lens, and the value obtained by converting the amount of protrusion of the focusing lens into the number of output pulses of the encoder by the above S and PTH, that is, the so-called lens drive amount FP, is given by the following equation. .

FP = DEF × S / PTH Step (1503) executes the above equation as it is.

At step (1504), step (50)
The FP obtained in step 3) is sent to the lens to instruct driving of the focus adjusting lens (in the case of the whole extension single lens, the entire photographing lens).

In the above description, there is used an example in which there are three independent distance measurement fields in the vertical direction in the selected distance measurement field block, but these distance measurement fields are formed by connecting a plurality of distance measurement fields. A series of distance measurement fields may be used, which is divided into a plurality of original areas, and the same processing as described above can be applied, for example, by replacing the right, center, and left with upper, center, and lower.

Although the embodiments described so far have described the passive type focus detecting device, the active type focus detecting device may be used. On the other hand, when the close distance is relatively long and parallax can be ignored, or a camera model that can compensate for it, there is a case where a detection device for external distance measurement can be used.

[0207]

As described above, according to the present invention, in the one-shot mode, the subject can be accurately photographed without inadvertently selecting the focus detection area based on the result of the visual line detection after focusing. Becomes possible.

[0208] After focusing, the line-of-sight detection is suppressed, but the focus detection is continued. Therefore, if the subject starts moving even in the one-shot mode, the mode is automatically changed to the servo mode, and the mode is changed according to the movement of the subject. It is possible to perform shooting in the shooting mode that has been set.

[Brief description of the drawings]

FIG. 1 is a flowchart schematically showing the overall operation of a camera.

FIG. 2 is a flowchart for explaining a control operation according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a subroutine of moving object detection.

FIG. 4 is a flowchart for explaining a subroutine of line-of-sight detection.

FIG. 5 is a flowchart illustrating a focus detection subroutine.

FIG. 6 is a flowchart illustrating a subroutine for determination.

FIG. 7 is a flowchart illustrating a prediction calculation subroutine.

FIG. 8 is a flowchart for explaining a subroutine for changing a ranging point.

FIG. 9 is a flowchart for explaining a subroutine relating to continuity of an image plane position.

FIG. 10 is a flowchart for explaining a subroutine relating to lens driving.

FIG. 11 is a flowchart illustrating a subroutine for setting a distance measurement visual field range.

FIG. 12 is a sectional view of a single-lens reflex camera according to the embodiment.

FIG. 13 is a diagram for explaining a method of detecting a line of sight.

FIG. 14 is a diagram illustrating an optical relationship between a reflected image of an anterior ocular segment and a pixel row of a photoelectric conversion element.

FIG. 15 is a diagram showing an optical relationship between an anterior segment and a Purkinje reflection image.

FIG. 16 illustrates an output of a photoelectric conversion element.

FIG. 17 is a perspective view of a focus detection device.

FIG. 18 is a diagram showing an optical behavior when detecting an on-axis detection visual field.

FIG. 19 is a diagram showing an optical behavior when detecting an off-axis detection visual field.

FIG. 20 is a diagram showing an example of an output signal for an arbitrary field of view of the focus detection device.

FIG. 21 is a diagram showing a state in which a detection visual field is displayed in a finder visual field of a single-lens reflex camera.

FIG. 22 is a front view of a multi-hole mask of the focus detection device.

FIG. 23 is a front view of a posture detection switch of the camera.

FIG. 24 is an electric block diagram of the camera.

[Explanation of symbols]

 Reference Signs List 2 Main mirror 3 Sub mirror 4 Camera body 5 Lens barrel 6 Focus detection device 9 Light splitter 13 Light source 14 Photoelectric converter 80 Movable mask 81 Field mask 83 Porous mask 84 Secondary imaging lens group

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-126211 (JP, A) JP-A-59-135448 (JP, A) JP-A-2-42430 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G02B ^7/ 28-7/40 G03B 13/36

Claims (1)

(57) [Claims] A lens control unit that controls a focus adjustment of the lens by driving the lens; a line-of-sight detection unit that detects line-of-sight position information of an observer's eyeball; of a selecting means for selecting a point detection area focus on the basis of the viewpoint position information, one of the focus detection area
In a focus detection means for performing focus detection, and the servo mode to correct by following the change of the focal plane position caused by the change in distance between the subject, the focus detecting means detects later to be a once-focus state and a one-shot mode for prohibiting the lens drive for focusing, the one-shot mode
Is in focus after detecting in focus with
A camera that switches from the one-shot mode to the servo mode in accordance with a focus detection result in a focus detection area in which a focus state is detected in the one-shot mode.
After that, the gaze detection means does not detect the gaze position information
It is detected that the focus detection means is in focus.
Focus detection is repeated in the focus detection area
When switched to the servo mode according to the result,
The line-of-sight detecting means detects line-of-sight position information, and
Focus detection area in which a step is selected based on the line-of-sight position information
A camera which performs focus detection in a camera.