JP3137216B2 - Focus area setting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus area setting device for detecting a direction of a photographer's line of sight and setting a focus area using information on the line of sight.

[0002]

2. Description of the Related Art Conventionally, various types of information have been obtained from a camera by, for example, a dial or a button, and the operating environment has become complicated as input information has increased.

For example, Japanese Patent Application Laid-Open No. Sho 60-33505 and Japanese Patent Application Laid-Open No. 1-155 / 1999 disclose a technique of detecting the direction of a photographer's line of sight looking into a finder and inputting information to a camera based on the line of sight information.
No. 90177, JP-A-61-61135, JP-A-63-94232.

Further, in recent cameras, a focus area is arranged in a wide range, and the camera automatically sets a focus area in order to reduce complexity.

However, even with such a camera, a focus area is not always automatically set at a place intended by a photographer. Further, setting a focus area by manual operation is still complicated, and easiness of a setting operation for a photographer to set a focus area at an arbitrary position has become important.

Therefore, there has been proposed an apparatus which detects the direction of the line of sight as described above and sets a focus area according to the detection result.

[0007]

As described above, when the direction of the line of sight is detected and the focus area is set in accordance with the detection result, the position (with or without glasses) that looks through the finder even if individual differences are adjusted. None, etc.) and the use state of an individual may not always set the focus area accurately.

[0008] In some cases, the focus area set by the line of sight is changed by other than the line of sight.

The focus area setting device of the present invention has been made in view of such a problem, and its purpose is to change the set focus area by a manual operation so that unnecessary eyes can be changed. An object of the present invention is to provide a focus area setting device capable of improving the operability of the focus area setting without changing the movement of the photographer to the photographer.

[0010]

In order to achieve the above object, a focus area setting device according to the present invention has a plurality of distance measuring frames, and is provided when a first release is in an ON state.
Distance measuring means for measuring a subject distance; gaze detection means for detecting a gaze direction in a finder of a photographer; focus area setting means for setting a focus area based on an output from the gaze detection means; The focus area set by the area setting means is set to 1
a focus area changing unit that changes the st release based on a manual operation when the st release is in an ON state .

[0011]

In other words, the focus area setting device of the present invention detects the direction of the line of sight of the photographer in the viewfinder and sets the focus area based on the detected output. Then, the set focus area is changed to the first focus.
When the release is ON, the value is changed based on a manual operation.

[0012]

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

As shown in FIG. 13, in general, when light 95 passes through an eyeball 90, reflection occurs at each interface. Anterior corneal surface 91, posterior corneal surface 91 ', anterior surface 9 of the lens
3 ', reflected at each interface of the posterior surface 93 "of the lens. The image formed by these reflections is well known to those skilled in the art and is generally called a Purkinje image.

Then, the reflected images from the respective interface portions are respectively
Purkinje statue, second Purkinje statue, third Purkinje statue,
It is called the fourth Purkinje image. In the figure, reference numeral 92 indicates an iris, 93 indicates a crystalline lens, 94 indicates a retina, and 97 indicates a sclera.

In the present invention, the line of sight is detected using the first Purkinje image. The first Purkinje image is a virtual image of a light source formed by light reflected from the front surface of the cornea 91, and is simply referred to as a corneal reflection image. It is the strongest reflection image called.

The first Purkinje image 95a which is the reflection image
14 is shown in FIG. 14 and emits light to the eyeball 90,
When the reflected image is captured, a first Purkinje image having a high light receiving output is detected. Note that it is difficult to detect Purkinje images other than the first Purkinje image 95a because the amount of reflected light is weak and the position where the reflected image can be formed is different.

Then, when light is projected onto the eyeball 90, the fundus image is detected as a silhouette of the peripheral edge 92 ' of the pupil by the reflected light 95b from the fundus. Reflected image 9 from this fundus
5b is shown in FIG. 14 together with the first Purkinje image 95a, and the gaze direction is detected using these two images.

The 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 is parallel to the light beam projected to the eye, the center of the fundus image 95b, that is, the center of the pupil and the center of the first Purkinje image 95a are arranged as shown in FIG. Match.

When the eyeball 90 rotates, the optical axis 98 rotates about the rotation center 90c of the eyeball 90 as shown in FIG. In that case, 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 receives light at a position relatively different from the center of the fundus image 95b. This is because the center of the curved surface in front 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 except for the finder can be obtained from the displacement of the absolute positions of the two images with respect to the sensor pixel row and the relative displacement of the two images. Further, it is possible to determine where the photographer is looking.

Next, the processing on the visual axis detection image employed by the present invention will be described.

When the corneal reflection image 95a and the fundus reflection image 95b are clearly detected, it is possible to accurately detect the line of sight. However, when the fundus reflection image 95b is distorted or the corneal reflection image 95a is not accurate. If it is not detected, it is impossible to detect the line of sight accurately.

Therefore, the differential processing is performed as shown in FIG. 4A, and the absolute value processing is performed on the signal subjected to the differential processing as shown in FIG. 4B. Then, by binarizing the signal subjected to the absolute value processing at a predetermined level Vs as shown in FIG. 4C, when the line of sight is normally detected as shown in FIG. Four signal components are detected.

In the present invention, the reliability of the visual line detection image is determined by such a calculation.

On the other hand, for detecting the rotation angle of the eyeball 90, the above-described processing is performed on the visual line detection image as shown in FIG. 5A, and a signal as shown in FIG. obtain. Note that, in both FIGS. 5A and 5B, the horizontal axis indicates the coordinates of the pixel row.

Then, in the signal shown in FIG.
Assuming that the center of the signals a and d is A, the center of the signals b and c is B, and the length between A and B is the center position interval X of the image, FIG.
As shown in (c), the center position interval X is proportional to the rotation angle θ of the eyeball. In the present invention, the rotation angle is calculated from such a relationship.

An embodiment of the present invention based on the above-described principle will be described below.

FIG. 1 is a diagram showing the configuration of the first embodiment of the present invention. As shown in FIG. 1, a line-of-sight detection device 1 that detects a line of sight of a photographer in a finder is connected to a focus area setting device 3 that sets a focus area based on line-of-sight information and the like. The focus area changing device 4 for changing the area is also connected to the focus area setting device 3. The focus area setting device 3 is a display device 5 for displaying the set focus area.
Is connected to a multi-ranging device that performs a focusing operation on a focus area set as follows.

In such a configuration, the focus area initially set is set by the focus area setting device 3 based on the line-of-sight signal of the line-of-sight detecting device 1 , displayed on the display device 5, and displayed by the multi-ranging device 2 . A focusing operation (ranging, lens driving) is performed.

When the focus area setting device 3 receives a signal from the focus area changing device 4 for changing the focus area set by the line of sight, the focus area setting device 3 responds to the signal from the focus area changing device 4. Changes the focus area, displays the changed focus area on the display device 5, and performs a focusing operation on the changed focus area.

FIG. 2 is a diagram showing the configuration of the second embodiment of the present invention.

As shown in FIG. 1, the multi-ranging circuit 11 is connected to a central processing unit (CPU) 13, which is connected to a display circuit 14. And
The CPU 13 is also connected to the taking lens 12.

Further, the CPU 13 is provided with a light emitting LED 17.
The projection LED 17 and the finder optical system 16 are connected to the visual line detection optical system 15. The line-of-sight detection optical system 15 is connected to a line-of-sight sensor 19, and the line-of-sight sensor 19 is connected to the CPU 13 via an analog / digital (A / D) circuit 18. Further, the CPU 13 is connected to a focus area change switch 20.

In such a configuration, when a command from the CPU 13 is received, light is emitted from the light emitting LED 17 to the eyeball (not shown) via the line-of-sight detection optical system 15 and the finder optical system 16. Then, the reflected light from the eyeball is again received by the line-of-sight sensor 19 via the finder optical system 16 and the line-of-sight detection optical system 15. The output signal from the line-of-sight sensor 19 is converted into a digital signal by the A / D circuit 18 and then input to the CPU 13.

The multi-ranging circuit 11 measures a distance in a set focus area. Furthermore, CPU
At 13, focusing information is set based on a signal from the multi-ranging circuit 11, a driving amount of the photographing lens 12 is calculated, and the photographing lens 12 is driven.

In the CPU 13, the A / D circuit 1
The line-of-sight direction is detected based on the digital signal from 8, and when the line-of-sight direction is the above-mentioned line-of-sight detection area, a focus area is set, and the focus area information is output to the display circuit 14. Then, the display circuit 14 displays information about the focus area.

Further, a focus area change switch 2
A value of 0 sends a change signal to the CPU 13 when it is desired to change the focus area set by the line of sight, and the CPU 13 changes the focus area according to the change signal of the focus area change switch 20. The multi-ranging circuit 11 measures the distance in the changed focus area. The display circuit 14 displays the changed focus area.

FIG. 3 is a diagram showing a detailed configuration of the visual axis detection optical system 15. As shown in FIG.
A half mirror 22 is disposed on the optical path of the light projected from the light source 7 via a light projecting lens 21, and the projected light is reflected by the half mirror 22. Then, a prism 23 is disposed on the optical path of the reflected light, and the reflected light is reflected by the reflecting surface 23a of the prism 23, and is reflected by the finder 24.
To the eyeball 90 of the photographer.

The reflected light from the photographer's eyeball passes through the same optical path as the incident light and passes through the finder 24 through the prism 2.
3 and is reflected by the reflection surface 23a. 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 incident on the prism via the display liquid crystal 26 which is superimposed on the subject light, and transmitted through the reflecting surface 23a, and further to the photographer's eyeball 90 via the finder 24. It is led.

Hereinafter, referring to the flowchart of FIG.
The main sequence of the present embodiment will be described. When the sequence is started (step S101), first, 1
The state of the first release (1stR) is detected (step S102). Step S when 1stR is “OFF”
Returning to step 102, if 1stR is "ON", initialization is performed (the flags F and DF (the flags will be described later), the counter FC and the timer T are set to 0, and the focus area is set to the center) (step S103).

In step S104, a subroutine program for line-of-sight detection is performed. Details of the operation of this subroutine program will be described later. Subsequently, a focus area is set based on the information detected by the line of sight, and the focus area is displayed on the display circuit 14 (step S105).

A focusing operation (AF: distance measurement, driving) is performed in a focus area set by the line of sight (step S10).
6). Next, the state of 1stR is determined again (step S111). If the 1stR is “OFF” (1stR is released), this sequence ends (step S13).
5) When 1stR is "ON" Input detection from the focus area change switch 20 (input as a pulse signal) is performed (step S112).

If there is an input from the focus area change switch 20, the process proceeds to step S121. If there is no input from the focus area change switch 20, the flag F (if the input from the focus area change switch 20 is "1"). And when it is determined, it returns to "0")
Is determined (step S113 ).

When the flag F is "1", the flow goes to S126, and when the flag F is "0", the second release (2nd release) is performed.
R) is determined (step 114). If 2ndR is "OFF", the process returns to step S111 and returns to 2ndR.
Is “ON”, the camera sequence after AF (exposure,
Winding, etc.) and go to step S135 (step S115).

If there is an input from the focus area change switch 20 in step S112, the timer T is reset (step S121). Then, the timer T starts counting time (step S122). The pulse signal input from the focus area change switch 20 is counted by an up / down counter FC, and a flag DF is determined according to the state of the FC (the moving direction of the focus area is determined. In the case of (1), a shift from the focus area position set by the line of sight to the right is set (step S123). Next, the flag F is set to "1" (step S124). Next, the changed focus area is displayed (step S12).
5). Next, the state of the timer T is determined (step S12).
6).

If the timer T has not overflown, the flow returns to step S111. If the timer T has overflown, the change of the focus area is determined according to the FC and DF signals (step S131). Next, the flag F is set to "0" (step S132). A focusing operation (AF) is performed in the changed focus area, and the process returns to step S111 (step S133).

Next, referring to the flowchart of FIG.
The sequence of the above-described line-of-sight detection subroutine program will be described.

When the present subroutine program is started (step S201), first, line-of-sight data is stored in a memory (step S202). Then, a differentiation process is performed on the stored line-of-sight data (step S20).
3). Further, after the signal subjected to the differential processing is binarized at a predetermined level (step S205), the centroid distance X between the corneal reflection and the fundus reflection is calculated (step S206), and the process exits from this sequence (step S207).

Next, the direction determination and the movement amount determination in step S123 of FIG. 6 will be described. FIG. 8 shows a signal relationship between the focus area change switch 20 and the CPU 13.
The focus area change switch 20 generates two types of signals, PA and DA, by the photographer's operation of changing the focus area. The CPU 13 determines the direction and amount of movement of the focus area based on the PA and DA signals.

FIG. 9 shows the mounting of the focus area change switch 20 when the focus area is arranged in one direction. When the line of sight input is used, the AF mode is set, and the focus area input switch is set by the focus ring of the lens barrel in FIG.

FIG. 16 shows the viewfinder.
(A) shows a state in which the focus area is set with the line of sight, and (b) shows a state in which the focus area change switch 20 has moved rightward by one step.

FIG. 10 shows a focus area change switch 2.
The state of the PA and DA signals from 0 is shown. The signal P out of phase due to the operation of the focus area change switch 20
A and DA (signals obtained by processing the switch signal by the chattering prevention circuit) are generated. (A) moves to the left,
(B) shows a rightward movement. (C) shows an actual signal generation pattern state of the focus area change switch 20. The hatched portion indicates the “ON” state, and the others indicate the “OFF” state.

FIG. 11 shows a flowchart of the direction determination by the CPU 13. First, the signal state of DA is detected according to the change of the PA signal (rising signal) (step S3).
02), the state of the DA signal is determined (step S30)
3). When DA = "H", up / down counter F
C is incremented (FC = FC + 1) (step S311). If DA = "L", the up / down counter FC is decremented (FC = FC-1) (step S312).

Next, the state of the FC is determined (step S).
313). When FC> 0, the flag DF is set to DF = "1"
(Step S321). If FC> 0, the flag DF is set to DF = "0" (step S32).
2). Then, the present sequence ends (step S32).
3).

Although the embodiment of the present invention has been described above, it is needless to say that the present invention is not limited to this embodiment, and various improvements and modifications can be made.

For example, AF may be performed on all focus areas in advance, and only lens drive may be performed when changing the focus area (visual line input, switch input). The display of the focus area may use a hologram element other than the liquid crystal. Further, the focus area change switch 20 may be arranged on the back of the camera as shown in FIG.

Further, for a two-dimensional change, a method as disclosed in Japanese Patent Application No. 02-235074 may be used (FIG. 17 shows a case where a two-dimensional focus area is provided, and FIG. (B) shows a state where the focus area is changed by one step in the lower right direction by the focus area change switch 20,
(C) shows a state where two steps have been changed downward from (a). ).

Although the determination of the changed focus area is determined after a predetermined time has elapsed, it may be combined with another switch, or may be determined immediately after the switch is input.

FIG. 12 shows a main flow of the third embodiment of the present invention. In this embodiment, the focus area is set at a predetermined position set by operating the focus area change switch 20. Step S401 to step S4
For 06, the same sequence as in S101 to S106 in FIG. 6 is performed.

Next, the state of 1stR is determined again (step S411). 1stR is “OFF” (1stR
If R is released, the present sequence is terminated (step S426), and if 1stR is "ON", input detection from the focus area change switch 20 (input as a pulse signal) is performed (step S412).

If there is an input from the focus area change switch 20, the flow proceeds to step S421, and if there is no input from the focus area change switch 20, 2nd
The release (2ndR) state is determined (step S4).
13).

When 2ndR is "OFF" Step S4
Returning to step 11, if 2ndR is "ON", the camera sequence (exposure, winding up, etc.) after AF is performed, and the procedure goes to step S426 (step S414).

In step S 412, if there is an input from the focus area change switch 20, the flag F (set to “1” when there is an input from the focus area change switch 20, and if set, return to “0”) A state determination is performed (step S421). If the flag F is "1", the flow proceeds to S411, and if the flag F is "0", the position of the predetermined focus area (camera position determination is performed by a camera vertical / horizontal position detecting device such as a mercury switch (not shown). In the case of the camera horizontal position, it is set to the center focus area, and in the case of the camera vertical position, it is set to the focus area slightly above the center (step S422). Next, the changed focus area is displayed (step S423). Perform focusing operation (AF) in the changed focus area
(Step S424), the process returns to step S111. The flag F is set to "1", and the process returns to step S411 (step S425).

FIGS. 18 and 19 show the viewfinder. FIG. 18 shows the case of the horizontal position, and FIG. 19 shows the case of the vertical position.

FIG. 18A shows a state of the focus area set by the line of sight, and FIG. 18B shows a state in which the focus area is changed to a predetermined position (center) by the focus area change switch 20.

FIG. 19A shows a state of the focus area set by the line of sight, and FIG. 19B shows a state where the focus area is changed to a predetermined position by the focus area change switch 20.

Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the embodiments and that various improvements and modifications can be made.

For example, AF may be performed on all focus areas in advance, and only lens drive may be performed when changing the focus area (view input, switch input). The display of the focus area may use a hologram element other than the liquid crystal. Alternatively, a focus area change switch button input may be used.

The focus area change switch 20
May be set in advance by the photographer. Alternatively, the setting may be made with an IC card or the like, or may be set in a shooting mode. Further, the size of the focus area may be increased (set to wide focus).

[0072]

As described in detail above, according to the present invention,
By changing the set focus area by manual operation, the operability of the focus area setting can be improved without making unnecessary eye movements to the photographer.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 3 is a diagram showing a detailed configuration of a visual line detection optical system.

FIG. 4 is a diagram for explaining a gaze detection processing step.

FIG. 5 is a diagram for explaining a detection process of a rotation angle of an eyeball.

FIG. 6 is a flowchart for explaining a main sequence of the present embodiment.

FIG. 7 is a flowchart illustrating a subroutine process of gaze detection.

FIG. 8 is a diagram illustrating a signal relationship between a focus area change switch and a CPU.

FIG. 9 is a mounting diagram of a focus area change switch when a focus area is arranged in one direction.

FIG. 10 shows PA from a focus area change switch,
FIG. 3 is a diagram illustrating a state of a DA signal.

FIG. 11 is a flowchart of handling of a focus area change signal by a CPU.

FIG. 12 is a flowchart illustrating a main flow of a third embodiment of the present invention.

FIG. 13 is a diagram for explaining a process in which a Purkinje image is formed.

FIG. 14 is a diagram illustrating a state of a first Purkinje image.

FIG. 15 is a diagram for explaining a change in a detected image due to rotation of an eyeball.

FIG. 16 is a diagram showing a viewfinder.

FIG. 17 is a diagram for describing a modification in which a focus area is provided two-dimensionally.

FIG. 18 shows a viewfinder in a horizontal position.

FIG. 19 shows a viewfinder in a vertical position.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Eye gaze detection device, 2 ... Multi-ranging device, 3 ... Focus area setting device, 4 ... Focus area change device, 5
... display device.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G02B ^7/ 28-7/40 G03B 3/00-3/12

Claims (1)

(57) [Claims] A first frame having a plurality of distance measurement frames;
Distance measuring means for measuring the subject distance when the camera is in the ON state; gaze detecting means for detecting the gaze direction in the viewfinder of the photographer; and focus for setting a focus area based on the output from the gaze detecting means. Area setting means, and the focus area set by the focus area setting means , when the first release is in the ON state.
And a focus area changing means for changing the focus area based on a manual operation.