JPH0720373A - Focus controller for camera - Google Patents

Abstract

PURPOSE:To optimumly and accurately set a defocus amount. CONSTITUTION:A multiple range-finding part 1 performs range-finding to plural discrete range-finding points, and a line-of-sight detection part 3 detects the position of the line of sight of a photographer with resolution finer than range- finding by the range-finding part 1. Based on range-finding information by the range-finding part 1 and the position of the line of sight, a defocus amount decision part 4 calculates the defocus amount of a photographing optical system. Then, focus control is performed based on the defocus amount, and positional relation between the position of the line of sight detected by the detection part 3 and the plural range-finding points is detected. Based on the positional relation, an algorithm for obtaining the defocus amount based on the range- finding information and the position of the line of sight is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus control device for a camera, which detects the direction of the line of sight of the photographer and determines the camera information based on the line-of-sight signal.

[0002]

2. Description of the Related Art Conventionally, in a camera having a multi-auto focus (multi-AF) function, it is necessary to select an optimum value from a plurality of AF data, and it is necessary to select an optimum value based on distance measurement data and focal length (f value). Is devising an ideal algorithm. In such a case, since the final distance measurement information is determined only on the camera side, the photographer's intention may not be completely captured, and the photograph may be out of focus.

In view of this problem, various techniques have been proposed for selecting a focus area by using a switch or line-of-sight input to capture the intention of the photographer. However,
Also in this case, it is difficult to say that the operability is good because the user of the compact camera needs to recognize the main subject and operate it according to the input format such as dial operation, button operation and calibration. Also, the compact camera is getting deeper and deeper due to the larger F-number due to the telephoto zoom and downsizing. However, the photographer of the compact camera is more concerned about the large-blur photo than the unfocused photo. There are many. Given these situations,
It is required that the photographer be able to take an optimal photograph by simply looking at the main subject without being aware of it.

In view of this problem, for example, JP-A-63-1
Japanese Patent Application Laid-Open No. 94237 and Japanese Patent Application Laid-Open No. 3-87818 disclose a technique of detecting a line-of-sight direction of a photographer looking into a viewfinder and inputting information to a camera based on the information of the line-of-sight. Japanese Patent Application Laid-Open No. 2-206425 discloses a technique relating to a detection method and the like. Further, JP-A-4-307506 and JP-A-5-88075 disclose techniques relating to determination of distance measurement information using a sight line detection position. Also, JP-A-59-146028
Japanese Patent Laid-Open Publication No. 1-276106 and Japanese Patent Laid-Open No. 1-276106 disclose an algorithm for determining the optimum distance measurement information from the multiple distance measurement information.

[0005]

In the camera having the multi-AF function as described above, it is necessary to select the optimum value from the multi-AF data. Therefore, the algorithm based on the distance measurement data and the focal length is devised. However, in this case, since the final distance measurement information is determined only on the camera side in this case, the intention of the photographer is not completely taken in.

When the focus area is thus selected by the switch or the line-of-sight input to input the intention of the photographer, the user of the compact camera needs to recognize the main subject and operate according to each input format. Therefore, it is hard to say that the operability is good.

Further, in the case of the above-mentioned line-of-sight input, since human eyes are always moving, it is hard to say that it is a method with a good usability to silently operate the main subject while taking a picture. Further, in the case of discretely arranged focus areas, the main subject and the focus areas do not coincide with each other. For example, if the vicinity of the boundary between the focus areas is selected, incorrect distance measurement will result.

The present invention has been made in view of the above problems, and an object of the present invention is to divide a selected area of a focus area according to the line of sight of a photographer according to processing contents, and to generate line of sight information and an algorithm for multi-distance measurement. By combining and using the above, the optimum defocus amount can be set more accurately without imposing a burden on the photographer.

[0009]

In order to solve the above problems, in a camera focus control apparatus of the present invention, a distance measuring means for performing distance measurement for a plurality of discrete distance measuring points, and the above-mentioned distance measuring means Line-of-sight detecting means for detecting the line-of-sight position of the photographer with a resolution finer than the distance-measuring point, and calculating means for calculating the defocus amount of the photographing optical system based on the distance-measurement information by the distance-measuring device and the line-of-sight position And a focus control device for a camera having a control means for performing focus control based on the defocus amount, for detecting a positional relationship between the sight line position detected by the sight line detecting means and the plurality of focus detection points. The present invention is characterized by including a positional relationship detecting means and a changing means for changing a calculation algorithm for obtaining a defocus amount based on the distance measurement information and the line-of-sight position based on the positional relationship.

[0010]

That is, in the focus control device for a camera of the present invention, the distance measuring means performs distance measurement for a plurality of discrete distance measuring points, and the line-of-sight detecting means has a finer resolution than the distance measuring points by the distance measuring means. The line-of-sight position of the photographer is detected, the calculation unit calculates the defocus amount of the photographing optical system based on the distance measurement information by the distance-measuring unit and the line-of-sight position, and the control unit based on the defocus amount. Focus control. The positional relationship detecting means detects the positional relationship between the line-of-sight position detected by the line-of-sight detecting means and the plurality of distance measuring points, and the changing means detects the distance measuring information and the line-of-sight position based on the positional relationship. The calculation algorithm for obtaining the amount of defocus is changed based on and.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention, the principle of line-of-sight detection adopted in the embodiments of the present invention will be described. There are various methods for detecting the line-of-sight direction. Here, a method for detecting the line-of-sight direction using a Purkinje image and a reflection image of the fundus or an edge of the iris will be briefly described as a method applicable to a camera. .

As shown in FIG. 13, when light 95 generally passes through the eyeball 90, reflection occurs at each interface. That is, it is reflected at the interfaces of the front surface 91 of the cornea, the rear surface 91 'of the cornea, the front surface 93' of the lens, and the rear surface 93 "of the lens. The images formed by these reflections are well known to those skilled in the art. , And is generally referred to as the Purkinje image, and the first Purkinje image from the front surface 91 of the cornea,
They are called the second Purkinje image, the third Purkinje image, and the fourth Purkinje image. In the figure, reference numeral 92 is an iris, and 93
Is a lens, 94 is a retina, and 97 is a sclera.

In the embodiment of the present invention, the line of sight is detected by using the first Purkinje image, and the first Purkinje image is a virtual image of a light source formed by reflected light from the anterior surface of the cornea 91, and is simply the cornea. This is the strongest reflection image, which is also called the reflection image.

The first Purkinje image 95a which is the reflection image
14 is shown in FIG. 14, in which light is projected onto the eyeball 90,
When the reflected image is captured, the first Purkinje image 95a having a high received light output is detected. The first Purkinje image 95
It is difficult to detect Purkinje images other than a because the amount of reflected light is weak and the position where a reflected image is formed is different.

Then, when light is projected onto the eyeball 90, the fundus image is detected as the silhouette of the peripheral edge 99 of the pupil by the reflected light 95b from the fundus. Reflected image 95 from this fundus
Although b is shown in FIG. 14 together with the first Purkinje image 95a, the line-of-sight direction is detected using these two images in the embodiment.

This detected image changes as shown in FIG. 15 due to the rotation of the eyeball. That is, when the optical axis 98 of the eyeball 90 and the light flux projected on the eye are parallel to each other, the center of the fundus image 95b, that is, the center of the pupil and the center of the first Purkinje image 95a coincide with each other, as shown in FIG. ing. When the eyeball 90 rotates, the optical axis 98 rotates around the rotation center 90c of the eyeball 90 as shown in FIG. In that case, the center of the fundus image 95b can be received at different positions on the sensor pixel row that receives the reflected light from the eye.

Further, the center of the first Purkinje image 95a is received at a position relatively different from the center of the fundus image 95b. This is because the center of the curved surface on the front surface of the cornea 91 is different from the center of rotation of the eyeball. Therefore, the amount of rotation and the amount of shift of the eyeball 90 of the photographer looking into the finder can be obtained from the displacement of the absolute positions of these two images with respect to the sensor pixel row and the relative displacement of the two images, and further, the photographing. It is possible to determine where the person is looking.

Next, the feature extraction processing from the line-of-sight detection image adopted by the embodiment of the present invention will be described. In the embodiment, feature extraction is detected using the corneal reflection image 95a or the fundus reflection image 95b.

First, FIGS. 16A to 16C show the corneal reflection 9
It is a figure which shows the relationship between 5a and the fundus reflex 95b. In the figure, px indicates the center of gravity of the corneal reflection 95a, and ix indicates the center of gravity of the fundus reflection 95b. If the center of the eyeball is fixed, the rotation angle can be detected by detecting the barycentric position ix of the fundus reflection 95b, the barycentric position px of the corneal reflection 95a, or the barycentric position including both. The fundus reflection shown in FIG. 16 is generally a red-eye state, that is, a state in which a large amount of light is reflected from the fundus. The output of the fundus reflex 95b further decreases. When viewed from the center of the finder, FIG. 16A shows the center at a rotation angle of “0”, FIG. 16B shows the left side with a negative rotation angle, and FIG. 16C shows the right side with a positive rotation angle. Will be there.

17 (a) to 17 (c) are diagrams showing the relationship between the corneal reflection 95a and the fundus reflection 95b. In the figure, px indicates the center of gravity of the corneal reflection 95a,
ix indicates the position of the center of gravity of the fundus reflection 95b. The approximate shift amount can be detected by detecting the barycentric position ix of the fundus reflection 95b, the barycentric position px of the corneal reflection 95a, or both of them. Then, as shown in FIG.
Similar to 6, the fundus reflection shown in FIG. 17 is generally a red-eye state, that is, a state in which a large amount of light is reflected from the fundus, and when it is not in a red-eye state, that is, when the iris is squeezed in a bright state or the reflected light returns to the light receiving system. If not, the output of the fundus reflex 95b is further reduced. And when viewed from the center of the viewfinder,
17A, the shift amount is “0”, the center is viewed, FIG. 17B is the shift amount is negative and the left side is viewed, and FIG. 17C is the shift amount is positive, and the right side is viewed.

As shown in FIGS. 16 and 17, by detecting the barycentric position of the detected light amount distribution, it is possible to almost detect which the line of sight is looking. Also, in general, one shutter sequence (2nd from near the 1st release)
During the release), the eye shift does not change significantly, and it is possible to determine the size of the range that the photographer intends to see by detecting the relative movement. Further, by performing reference position detection in the sequence, it is possible to detect the approximate position to be seen.

An embodiment of the present invention based on the above-mentioned principle will be described below. 1 is a diagram showing the configuration of a focus control device for a camera according to a first embodiment of the present invention.
As shown in FIG. 1, the multi-distance measuring unit 1, the photometric unit 2, the line-of-sight detecting unit 3, and the block dividing unit 5 are connected to the defocus amount determining unit 4, and the respective information is defocused by the defocus amount determining unit 4. Send to. The photographing optical system 6 is connected to the defocus amount determining unit 4, and the photographing optical system 6 sends information to the defocus amount determining unit 3 and receives information from the defocus amount determining unit 4.

In such a configuration, the multi-range finding section 1
Performs the distance measurement at a plurality of points and sends the distance measurement information to the defocus amount determination unit 4, the photometry unit 2 sends the photometry information to the defocus amount determination unit 4, and the line-of-sight detection unit 3 relates to the position viewed by the photographer. The information is sent to the defocus amount determination unit 4. Then, the photographing optical system 6 sends information about the focal length (f value) and the aperture (Fno) to the defocus amount determination unit 4, and the block division unit 5 sets the block for line-of-sight detection and determines the set information. Send to Part 4. Further, the defocus amount determination unit 4 uses the photometric system 6 based on the photometric information, the photographic optical system information, the line-of-sight information, the multi-measurement information, and the block information.
Determine the defocus amount of.

Next, FIG. 2 is a diagram showing the structure of a focus control device for a camera according to a second embodiment, which is a further implementation of the first embodiment. In this embodiment, the focus area of the horizontally arranged three-point AF is selected using the line-of-sight signal.

In FIG. 2, a multi-point distance measuring circuit (multi-AF circuit) 11, a photometric circuit (AE circuit) 21, and a photographing lens 14 are connected to a central processing unit (CPU) 12, and the CPU 12 displays. It is connected to the circuit 13. The CPU 12 is also connected to the lens 14 via a drive circuit 15, and the CPU 12 is further connected.
Is also connected to the light emitting LED 17, and the light emitting LED 1
7 and the finder optical system 16 are connected to the visual axis detection optical system 18. The visual axis detection optical system 18 is connected to a visual axis sensor (PSD) 19, and the PSD 19
Outputs a signal corresponding to the detection of the center of gravity of the light quantity, and the CPU 12 through the interface circuit (I / F circuit) 20.
It is connected to the.

In such a configuration, the multi-AF circuit 11 measures the distance to a plurality of points and sends the distance measurement information to the CPU 12, the AE circuit 21 sends the photometry information to the CPU 12, and the lens 14 the focal length information (zoom value, zoom value, (Aperture range information) is C
Send to PU14. When the line-of-sight detection system receives a command from the CPU 12, light is emitted from the light emitting LED 17 to the eyeball 90 via the line-of-sight detection optical system 18 and the finder optical system 16. Further, the reflected light from the eyeball is again received by the visual axis sensor 19 via the finder optical system 16 and the visual axis detecting optical system 18. And this PSD19
The output signal from the I / F circuit 20 is converted into a signal corresponding to the position of the center of gravity and a signal corresponding to the brightness, and then the CP
Input to U12. And this CPU 12 is an I / F
The circuit 20 detects the blink and the defocus amount based on the information about the line of sight, the information about the brightness, and the multi-AF circuit 11 based on the distance measurement information of a plurality of points. Further, the lens 14 is driven via the drive circuit 15 with the set defocus amount.

The detailed structure of the visual axis detecting optical system 18 is as shown in FIG. As shown in this FIG.
The projection lens 2 is provided on the optical path of the projection light from the projection LED 17.
A half mirror 22 is arranged via 7 and the projected light is reflected by the half mirror 22. And
A prism 23 is arranged on the optical path of this reflected light, and the reflected light is reflected by the anti-slope 23a of the prism 23 and guided to the eyeball 90 of the photographer through the finder 24. Then, the reflected light from the eyeball of the photographer passes through the same optical path as the incident light and passes through the viewfinder 24 to the prism 2
3 and is reflected by the reflecting surface 23a. Then, the reflected light passes through the half mirror 22 and is received by the line-of-sight sensor 19 via the light receiving lens 25.

On the other hand, the subject light is made incident on the prism through the display liquid crystal 26 which is superposed on the subject light and indicates a display, passes through the anti-slope 23a thereof, and further passes through the viewfinder 24 to the eyeball 90 of the photographer. Is led.

The viewfinder display is as shown in FIG. That is, FIGS. 4 (a) and 4 (c) show the case of displaying in the center of the screen by superimposing, and FIG.
(D) shows the case where it is displayed in the frame portion. In addition, the line-of-sight mode display lights up in the line-of-sight detection mode, and blinks when the line-of-sight cannot be detected.

Hereinafter, with reference to the flowchart of FIG.
The main sequence of the second embodiment will be described. When the main sequence is started (step S1), first 1
Whether the st release switch is turned on or off is determined (step S2). If the 1st release switch is off, the process proceeds to step S15, and if the 1st release switch is on, the initialization is continued. Here, the focus area is set to the center (step S
3).

Subsequently, a subroutine "line-of-sight detection" which will be described later is executed to detect the line-of-sight direction (step S4).
Further, the line-of-sight coordinates X (line-of-sight center of gravity) detected in this subroutine "line-of-sight detection" are input to the flag X1 and FX to the flag F1 (step S5). And multi A
Perform F and AE. Here, AF data are LL and L from the left.
The AF method may be a known phase difference method or an active method with C and LR (step S6).

Then, a display for detecting the reference position of the line of sight is displayed. It is even better to do this with display flashing or sound. It may also be used as an AF end signal (step S7). Then, the subroutine "line of sight detection" is executed again to detect the line of sight (step S8), and the detected line of sight coordinates X (center of gravity of line of sight) is stored in the flag X0 and FX is stored in the flag F0 (step S9). .

Then, a subroutine "focus area setting" which will be described later is executed (step S10), and it is determined whether the first release switch is on or off (step S).
11). If the 1st release switch is off, the process proceeds to step S15, and if the 1st release switch is on, it is determined whether the 2nd release switch is on or off (step S12).

If the 2nd release switch is off, the process returns to step S11, and if the 2nd release switch is on, the defocus amount determined by the distance measurement data L of the set focus area is determined. To drive the lens (step S13). Subsequently, a camera sequence such as an exposure sequence and a winding sequence is performed (step S14), and this sequence ends (step S15).

Next, the sequence of the above subroutine "line of sight detection" will be described with reference to the flow chart of FIG.
When this subroutine "line-of-sight detection" is started (step S21), first, initialization is performed. Here, variables i, m, E, X and flag FX (a flag for evaluating the effectiveness of the line-of-sight signal) are initialized to "0" (step S2).
2). Then, after incrementing the variable i (step 23), the light of the IRED 17 is projected onto the eyes of the photographer (step S24), and a signal (total current value) corresponding to the amount of light is synchronized with the projection of the IRED 17 Is detected as Ei (step S25). Then, the barycentric coordinate Xi is detected (step S26), and the signal corresponding to the brightness is added (E = E + Ei) (step S27).

Then, the number of times of detection is determined (step S28). If i = K (K: predetermined value) is not satisfied, the process returns to step S23, and if i = K, the signal E ( E = E / K) is detected (step S2)
9).

Further, the signal E corresponding to the average brightness
(E0 <E <E1; E0 and E1 are predetermined values) is evaluated (step S36). If not E0 <E <E1, the flag FX is set to "1" to exit the present sequence (step S37). If E0 <E <E1, set the variable i to "0" ( In step S38), the variable i is incremented (step S30).

Then, the blink is determined from each detected current. Here, when the absolute value of the difference between the detected current Ei and the average current E is larger than the predetermined value d, it is determined that the eye blinks. Alternatively, the determination may be made by the ratio of the detected current Ei and the average current E (step S31).

At step S31, | Ei-E | <
If not d, the process proceeds to step S34 and | Ei-E
If | <d, the total sum X (X = X + Xi) of the centers of gravity is calculated (step S32). Then, after incrementing the variable m (step S33), the number of eye-gaze calculation times is determined (step S34). Then, if i = K is not satisfied, the process returns to step S30, and if i = K, the average value of the center of gravity (X = X / m) is calculated (step S35). In this way, the system is terminated and the process returns to the main sequence (step S39).

Here, FIG. 7 is a diagram showing a state in which the line-of-sight detection area is divided. First, in FIG. 7A, the line-of-sight detection area is algorithmically <A * (*; L, C, R)>, <B *.
(*; L, C1, C2, R)>, <C * (*; L, R)
>, <D * (*; L, R)> are divided into four types, and they are arranged symmetrically with the center as the origin.

The function of each algorithm is that <A *> sets the defocus amount by the distance measurement information of the target focus area, <B *> sets the defocus amount that puts the target focus area within the depth, <C *> is set from the information of two adjacent focus areas, and <D *> is set from the information of the entire focus areas. Further, the distance from the origin to the block <AC> is a, the distance to <BC> is b, the distance to <CR> is c, the distance to <AR> is d, and the distance to <LR> is e. And Since the drawing is symmetrical with respect to the left and right, only the one-sided coordinates are shown.

On the other hand, in FIG. 7B, the line-of-sight detection areas are <A * (*; L, C, R)>, <B * (*; L1,
L2, C1, C2, R1, R2)>, <C * (*; L,
R)>, <D * (*; L, R)> are divided into four types, and they are arranged symmetrically with the center as the origin. The function of each algorithm is the same as that shown in FIG.

Hereinafter, with reference to the flowchart of FIG.
The sequence of the subroutine "focus area setting" will be described. When the sequence of this subroutine "focus area setting" is started (step S40), the flags F0 and F1 are first determined (step S41).
Then, if either of the flags F0 and F1 has "1", the distance measurement information L is set by the known multi-AF algorithm (the eye sight information is not used) as the distance measurement information (step S67). After the mode mark blinks and a warning is displayed, this sequence is exited (step S68).

On the other hand, in step S41, the flag F0,
If there is no "1" in either F1, the amount of movement of the line of sight (X1-X0) is stored in the variable Z (step S4
2) The movement amount Z is determined (steps S43 to S52).

When Z <-e, L1 = LL, L
After setting 2 = LC and L3 = LR, a subroutine “process D” described later is executed (steps S43, 53, 66),
When −e ≦ Z <−d, L = LL is set, and then the present sequence is exited (steps S44, 54, 69). And
When −d ≦ Z <−c, L1 = LL and L2 = LC are set, and then a subroutine “process B” described later is executed (steps S45, 55, 64), and when −c ≦ Z <−b, L1
= LL, L2 = LC, a subroutine "process C" described later is executed (steps S46, 56, 6).
5).

Further, when -b≤Z <-a, L1 = L
After setting C and L2 = LL, a subroutine "process B" described later is executed (steps S47, 57, 64), and -a≤
When Z <a, L = LC is set, and then the present sequence is exited (steps S48, 58, 69). Also, a ≦ Z <b
In case of, L1 = LC and L2 = LR are set, and then a subroutine “process B” described later is executed (steps S49, 5).
9, 64), and when b ≦ Z <c, L1 = LC, L2 = L
After setting to R, a subroutine "process C" described later is executed (steps S50, 60, 65).

When c≤Z <d, L1 = LR,
After setting L2 = LC, a subroutine “process B” described later
Is executed (steps S51, 61, 64), and d ≦ Z <e
In this case, after L = LR, this sequence is exited (steps S52, 62, 69). Further, when e ≦ Z, L1 = LR, L2 = LC, L3 = LL are set, and then a subroutine “process D” described later is executed (step S5).
2, 63, 69).

In this way, after the subroutines "process B", "process C", and "process D" are executed according to the respective processes, the present sequence is exited (step S69). Next, the sequence of the subroutine "process B" will be described with reference to the flowchart of FIG. This sequence is for setting the adjacent focus area so as to be within a predetermined depth, and when this sequence is started (step S70),
First, the hyperfocal length K (K = f ² / (δ0 * Fno): f is the focal length of the lens, Fno is the aperture value at the time of shooting, and δ0 is the set permissible circle of confusion) (step S71).

Subsequently, the magnitude relationship between L1 and L2 is determined (step S72), and the distance measurement data L is set according to the determination result. That is, when L1> L2, L = K * L
1 / (K + L1) (step S73), L1 ≦ L2
If, then L = K * L1 / (K-L1) is set (step S74). In this way, the present sequence is exited (step S75).

Next, the sequence of the subroutine "process C" will be described with reference to the flowchart of FIG. This sequence is for setting the focus areas on the near side of the distance measurement data of two focus areas so as to be within a predetermined depth. When this sequence is started (step S80), first, the hyperfocal distance K (K = F ² / (δ1 *
Fno): f is the focal length of the lens, Fno is the aperture value at the time of shooting, and δ1 is the set permissible circle of confusion (step S).
81). Subsequently, the magnitude relationship between L1 and L2 is determined (step S82), and the distance measurement data L is set according to the determination result. That is, when L1> L2, L = K * L
2 / (K−L2) (step S83), L1 ≦ L2
If, then L = K * L1 / (K-L1) is set (step S84). In this way, the present sequence is exited (step S85).

Next, the sequence of the subroutine "process D" will be described with reference to the flowchart of FIG. This sequence is for setting the adjacent focus areas so as to be within a predetermined depth based on the relationship between the distance measurement data of the three focus areas. When this sequence is started (step S90), first, the hyperfocal distance K ( K = f ² /
(Δ1 * Fno): f is the focal length of the lens, Fno is the aperture value at the time of shooting, and δ1 is the set permissible circle of confusion (step S91). Subsequently, the magnitude relationship between L1, L2, and L3 is determined (steps S92 to S94), and the distance measurement data L is set according to the determination result. That is, L1> L
In the case of 2 and L3, L = K * L1 / (K + L1) is set (step S95), and L3 ≧ L1> L2, L2 ≧ L1 ≧
When L3, L = L1 (step S96), L1 ≦
When L2, L1 <L3, L = K * L1 / (K-L1)
(Step S97). In this way, the present sequence is exited (step S98).

Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to these and various improvements and modifications can be made. For example, a sensor (line sensor or the like) other than PSD may be used as long as the center of gravity can be detected. Then, instead of corneal reflection, the ratio of white eye / black eye may be detected by the photodiode and used as eye movement. Further, the position viewed by the photographer may be detected at once using the glow and the Purkinje image. Further, if the distance measuring points are plural, it is not necessary to be caught by three points.

If it is not necessary to detect the line of sight as the sequence of the camera (when the distance measuring point is within the depth, etc.), the line of sight detection sequence may be omitted. Furthermore, the algorithms of the divided focus areas may be combined with each other. For example, a well-known multi-AF selection algorithm such as closest selection from two adjacent data may be set by the subroutine "Processing C".
Further, it may be set at the center of two adjacent data by the subroutine "process C". Then, the processing may be simplified by using a well-known multi-AF selection algorithm such as the closest selection from the entire data by the subroutine "processing D". In addition, the line-of-sight detection area is shown in FIG.
The algorithm may be changed according to the focal length of the taking lens as shown in (b).

[0054]

As described in detail above, according to the present invention,
By dividing the selected area of the focus area according to the photographer's line of sight according to the processing contents and using the combination of the line-of-sight information and the multi-distance measurement algorithm, the simple configuration does not burden the photographer. A focus control device for a camera can be provided in which an optimal defocus amount is set accurately and a photograph in focus is obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a focus control device for a camera according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a focus control device for a camera according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a detailed configuration of a line-of-sight detection optical system 18.

FIG. 4 is a diagram showing how a finder display is displayed.

FIG. 5 is a flowchart showing a main sequence of the second embodiment.

FIG. 6 is a flowchart showing a sequence of a subroutine “visual axis detection”.

FIG. 7 is a diagram showing a state in which a visual line detection area is divided.

FIG. 8 is a flowchart showing a sequence of a subroutine “focus area setting”.

FIG. 9 is a flowchart showing a sequence of a subroutine “process B”.

FIG. 10 is a flowchart showing a sequence of a subroutine “process C”.

FIG. 11 is a flowchart showing a sequence of a subroutine “process D”.

FIG. 12 is a diagram showing a state in which the line-of-sight detection area is divided according to the focal length of the photographing lens.

FIG. 13 is a diagram showing the structure of a human eyeball.

FIG. 14 is a diagram showing a state of a first Purkinje image 95a which is a corneal reflection image.

FIG. 15 is a diagram showing how the first Purkinje image 95a changes as the eyeball rotates.

FIG. 16 is a diagram showing a relationship between a corneal reflection 95a and a fundus reflection 95b.

FIG. 17 is a diagram showing a relationship between a corneal reflection 95a and a fundus reflection 95b.

[Explanation of symbols]

1 ... Multi distance measuring unit, 2 ... Photometric unit, 3 ... Line-of-sight detecting unit, 4 ...
Defocus amount determination unit, 5 ... Block division unit, 6 ... Shooting optical system.

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Claims (1)

[Claims] 1. A distance measuring means for performing distance measurement for a plurality of discrete distance measuring points, and a visual axis detecting means for detecting a visual axis position of a photographer with a resolution finer than that of the distance measuring points by the distance measuring means, A camera having a calculating means for calculating the defocus amount of the photographing optical system based on the distance measurement information by the distance measuring means and the line-of-sight position, and a control means for performing focus control based on the defocus amount. In the focus control device, a positional relationship detecting unit that detects a positional relationship between the line-of-sight position detected by the line-of-sight detecting unit and the plurality of distance measuring points, and the distance measuring information and the line-of-sight position based on the positional relationship. And a changing means for changing a calculation algorithm for obtaining a defocus amount based on the following.