JPH0694980A - Camera provided with device for detecting line of sight - Google Patents

Abstract

PURPOSE:To easily and surely calculate the direction of a line of sight by constituting plural light sources of a 1st light source arranged on an optical axis equivalent to the optical axis of a finder for a camera and a 2nd light source arranged on the axis having a prescribed inclination with reference to the optical axis of the finder. CONSTITUTION:A light source switching part 2 functions as a light switching part for switching the light sources which are installed for detecting the line of sight in order to detect the line of sight by use of at least either of two light sources for illuminating photographer's eye, and the switching control is performed by a control part 1 based on the output of a photometry part 6. And the ambient brightness of the eye is measured by the photometry part 6, and when the brightness is equal to or exceeding a prescribed value, a light source for detecting the line of sight which is arranged on the axis having the prescribed inclination with reference to an observation optical axis (optical axis of finder for camera) is used. Meanwhile, when the ambient brightness of the eye is equal to or below the prescribed value, the light source for detecting the line of sight which is arranged on the axis equivalent to the observation optical axis is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera with a line-of-sight detecting device having a function of detecting the line of sight of a photographer and detecting a subject to be photographed.

[0002]

2. Description of the Related Art Conventionally, as described in Japanese Patent Laid-Open No. 2-5, etc., as a method for detecting the line of sight of a photographer, the illumination means is arranged with the photographer's eyes on an axis equivalent to the optical axis of the finder. It is known that the photographer's line-of-sight position is detected from the relative position between the position of the reflected image (hereinafter referred to as Purkinje 1 image) on the cornea and the center position of the pupil due to the illumination light. Further, the illuminating means arranged on the optical axis having a predetermined inclination with respect to the optical axis of the viewfinder illuminates, and the line-of-sight position of the photographer is determined from the relative position between the Purkinje 1 image position and the center position of the pupil by the illuminating light. Japanese Patent Application Laid-Open No. Sho 6
3-194237 etc. are known.

[0003]

However, when the Purkinje 1 image and the image of the pupil are obtained by illuminating from the optical axis of the finder, the pupil part, the iris and the white part of the eye are reflected by the retina when the surroundings of the eye are dark. Although it is possible to discriminate, when the surroundings of the eye are bright, the pupil shrinks, and the reflected light from the retina cannot be detected so that the pupil part cannot be discriminated from the iris and the white eye part. Further, when the Purkinje 1 image and the pupil image are obtained by illuminating from the optical axis having a predetermined inclination with respect to the finder optical axis, there is almost no reflection from the retina because the illuminating means is displaced from the finder optical axis. The pupil part looks black. Therefore, when the brightness around the eyes is bright, the pupil part can be discriminated from the iris and the white part of the eye, but when the surroundings of the eye are dark, the entire eye becomes dark, so the pupil part can be distinguished from the iris and the white part of the eye. There was a problem that it became difficult to do.

[0004]

Therefore, a camera with a line-of-sight detecting device according to a first aspect of the present invention includes an illuminating means 3 composed of a plurality of light sources for illuminating an eye of a photographer, and the eye illuminated by the illuminating means 3. A light receiving means 5 for receiving the reflected light from
Photometric means 6 for measuring the brightness around the eyes of the photographer
A light source switching means 2 for switching the plurality of light sources, an operation of the illuminating means 3, the light receiving means 5, the photometric means 6, and the light source switching means 2 and an output from the light receiving means 5. The control means 1 for calculating the line-of-sight direction based on the above.

According to a second aspect of the present invention, in the camera with the line-of-sight detection device according to the first aspect, the plurality of light sources are arranged on an optical axis equivalent to a finder optical axis of the camera.
3 and a second light source 304 arranged on an axis having a predetermined inclination with respect to the finder optical axis. According to a third aspect of the present invention, in the camera with a line-of-sight detection device according to the first aspect, the photometric means 6 for measuring the brightness around the eye also serves as the photometric means of the camera.

[0006]

In the present invention, the brightness around the eye is measured, and when the brightness is above a predetermined value, it is placed on an axis having a predetermined inclination with respect to the observation optical axis (camera finder optical axis). Since the light source for line-of-sight detection is used, there is almost no reflection from the retina, the pupil part appears black, and the output of the photoelectric conversion element due to the reflected light from the pupil part is reflected by the reflected light from the iris part and the white eye part. The output is lower than the output of the conversion element, the pupil part is clearly discriminated from the iris part, and the white part of the eye, and the line-of-sight direction can be calculated easily and surely. Also, when the brightness around the eyes is less than a predetermined value, the line-of-sight detection light source placed on the axis equivalent to the observation optical axis (camera finder optical axis) is used, The pupil part becomes red-eyed and looks bright, and the output of the photoelectric conversion element due to the reflected light from the pupil part becomes higher than the output of the photoelectric conversion element due to the reflected light from the iris part and the white eye part, and the pupil part, the iris part and the white eye part Can be clearly discriminated from each other, and the line-of-sight direction can be calculated easily and surely.

[0007]

EXAMPLES Examples of the present invention will be described below. Figure 1
1 is a block diagram showing a configuration of a visual line detection device according to a first exemplary embodiment of the present invention. FIG. 2 is a configuration diagram including an optical system of a camera with a visual axis detection device according to the first embodiment of the present invention.

In FIG. 1 and FIG. 2, a control unit 1 is a control unit (CP) which controls the entire line-of-sight position detecting apparatus of this embodiment.
U). The light source switching unit 2 is a light source switching unit that switches the light source for detecting the line of sight using at least one of the two light sources for illuminating the eye of the photographer, which is provided for detecting the line of sight. Switching control is performed by the control unit 1 based on the output of the unit 6. Details will be described later.

The illumination unit 3 is an illumination unit for detecting the line of sight,
As shown in FIG. 2, it is composed of a light source 212 and an optical system 210. Light from the light source 212 passes through the optical system 210 and is reflected by the optical path splitting unit 209 in the eyepiece 207, and the eyes of the photographer. Is emitted as substantially parallel light. Light source 21
Reference numeral 2 is a light source for detecting the line of sight, and as shown in FIG. 3, has two light sources, a first light source 303 and a second light source 304.
This light source is connected to the light source switching unit 2, and the control unit 1 controls the first light source 30 based on the output of the photometric unit 214.
The switching of the light source 3 and the second light source 304 is controlled, and the control unit 1 controls the lighting. Here the light source 21
Reference numeral 2 denotes an infrared light emitting LED, which passes through the optical system 210 and is reflected by the half mirror 209 in the eyepiece 207 to the eye 2 of the photographer.
It is bent toward 08 and is irradiated on the eye 208 as substantially parallel light. A dichroic mirror that reflects infrared light is used as the half mirror 209. Light source 212
The light reflected by the eye 208 is bent by the half mirror 209 in the eyepiece 207 toward the light source 212 side, passes through the optical system 210, and further separates the light from the light source 212 and the reflected light from the eye 211. It is bent at and reaches the photoelectric conversion element 213. Here, an image of the photographer's eye 208 is formed on the photoelectric conversion element 213. Photoelectric conversion element 2
The photoelectric conversion element 213 is connected to the control unit 1.
Is sent to the control unit 1.

The distance measuring unit 4 has a plurality of distance measuring areas A1, A2, A3 in the finder 801 as shown in FIG.
Distance measurement is performed for each distance measurement area. Although the distance measuring area is discrete in this embodiment, it may be a continuous distance measuring area. The light receiving unit 5 is a light receiving unit for detecting the line of sight, and includes the optical system 210 and the photoelectric conversion element 213 in FIG. 2 (the optical system 210 is shared by the configuration of the illumination unit 3), and the photoelectric conversion element 213 includes A photoelectric conversion element such as a one-dimensional or two-dimensional CCD is used. The signal output from the light receiving unit 5 is sent to the control unit 1,
The Purkinje 1 image position and the pupil center position are detected, and the control unit 1 calculates the line-of-sight direction based on the Purkinje 1 image position and the pupil center position.

The photometric section 6 measures the brightness of external light applied to the photographer's eyes. In the embodiment of the present invention, the photometric unit 6 also serves as the photometric unit of the camera in the camera with the visual axis detection device shown in FIG. The metering section of the camera
It is arranged above the surface of the finder 206 on the side of the eyepiece 207, and performs photometry of the photographing screen. This photometric unit has a photometric area obtained by dividing the photographic screen into a plurality of areas, and an exposure signal is generated by the control unit 1 based on a plurality of photometric signals detected here and a line-of-sight signal, which will be described later, and the exposure unit 8 is driven. Is controlled. Then, as described above, it is also used for photometry of the brightness around the eye, and the photometric value is also used as information for the selection control of the light source for sight line detection.

The lens driving section 7 is provided with a photographing lens 2 according to the amount of movement of the focus matching lens calculated by the control section 1.
01 is drive-controlled. The exposure unit 8 controls the shutter speed and the aperture value based on the exposure value calculated by the control unit 1. The half-push switch SW1 is connected to the control unit 1 and is turned on by half-pushing the release button.

The full-press switch SW2 is connected to the controller 1 and is turned on by full-pressing the release button. Display unit 217
Selects and displays the range-finding area closest to the obtained line-of-sight position, and displays the control modes such as range-finding and photometry. Figure 2
In, the subject light that has passed through the taking lens 201 is split by the main mirror 202 into the finder screen 205 side and the distance measuring unit 4 side, and the light to the distance measuring unit 4 is sub mirror 20.
The optical path is further bent at 3 and is guided to the distance measuring unit 4.

On the other hand, the light guided to the finder screen 205 side by the main mirror 202 forms a subject image on the finder screen 205. The subject image passes through the viewfinder 206 and is guided to the photographer's eye 208. FIG. 3 is a diagram for explaining the line-of-sight detection device portion in detail. In FIG. 3, the first light source 303 is one of the light sources constituting the light source 212 shown in FIG. 2, and is placed on an axis 219 equivalent to the observation optical axis 218 of the photographer (coincident with the finder optical axis of the camera). It is arranged.

The second light source 304 is the light source 21 shown in FIG.
2, which is one of the light sources constituting the observation light source 21 and is the observation optical axis 21 of the photographer.
8 (corresponding to the finder optical axis of the camera) is arranged on an axis 301 having a predetermined inclination. The light source switching unit 2 switches the light source to detect the line of sight by using at least one of the two light sources 303 and 304 for illuminating the eyes of the photographer, and the photometric unit shown in FIG. Switching control is performed by the control signal of the control unit 1 based on the output of 6.

The first light source 303 or the second light source 304 whose lighting is controlled by the control unit 1 is an infrared light emitting LED, passes through the optical system 210, and reaches the photographer's eye 208 by the half mirror 209 in the eyepiece 207. Bent towards
The eye 208 is irradiated with substantially parallel light. A dichroic mirror that reflects infrared light is used as the half mirror 209.

The reflected light from the eye 208 of the first light source 303 or the second light source 304 is bent toward the light source side by the half mirror 209 in the eyepiece lens 207 and passes through the optical system 210.
Further, it is bent by the half mirror 211 that separates the light from the light source and the reflected light from the eye, and reaches the photoelectric conversion element 213. The photoelectric conversion element 213 has an eye 208 of the photographer.
Image is formed. The photoelectric conversion element 213 is the control unit 1
The output signal of the photoelectric conversion element 213 is A / D converted by an A / D converter (not shown).
The intensity distribution of the eye image formed on the photoelectric conversion element 213 is input to. Then, the control unit 1 calculates the signal from the photoelectric conversion element 213 to calculate the line-of-sight direction. In the eyepiece 207 of this embodiment, the bottom surface 302
Has an inclination of a predetermined angle with respect to the optical axis 219. This is because the light from the first light source 303 or the second light source 304 enters the eyepiece lens and is reflected by the half mirror 209, but the light that passes through without being reflected here is reflected by the bottom surface 302 and is reflected by the photoelectric conversion element 213. It prevents the light from entering as a ghost light.

FIGS. 4 to 6 show examples of output signals of the image of the eye 208 by the photoelectric conversion element 213. The vertical axis represents the output of the photoelectric conversion element 213 and the horizontal axis represents the position on the photoelectric conversion element 213. Shows. The peak output shown as P1 image in each figure is the light reflected by the cornea of the eye 208 as described in the prior art, and is called Purkinje 1 image (hereinafter referred to as P1 image). Photoelectric conversion element 213
Image a bright spot on top. On both sides of the P1 image, an output by the reflected light of the pupil part 41 is obtained, and on both sides of the pupil part 41, the iris part 4 is formed.
The output by the reflected light of 2 and the white part 43 is obtained.

In FIG. 4, FIG. 4 (a) and FIG.
FIG. 4 (b) is based on the second light source 304 arranged on the optical axis 301, and FIG. 4 (c) is based on the first light source 303 arranged on the axis 219 equivalent to the optical axis 218. Here, the output signal of the photoelectric conversion element 213 from the first light source 303 is shown in a convex shape in which the pupil part 41 is in a red-eye state due to reflection from the retina and is brightly reflected, and the second light source 304
The output signal of the photoelectric conversion element 213 by is almost concave from the iris portion 42 and the white eye portion 43 because the pupil portion 41 looks black because there is almost no reflection from the retina. FIG. 5 shows an output example by the first light source 303 arranged on the axis equivalent to the optical axis 218 shown in FIG. 4C.

FIG. 5A shows an output example of the photoelectric conversion element 213 when the brightness around the eyes is dark and the reflected light in the red-eye state of the pupil portion 41 is detected relatively strongly.
In this case, the output of the P1 image, the output of the pupil portion 41, and the iris portion 4
The outputs of 2 and the white-eye portion 43 can be clearly discriminated, and the line-of-sight direction is obtained by detecting the line-of-sight from the P1 image position and the pupil center position as described in the prior art. As a method of discriminating these outputs, a conventionally used method can be applied, and therefore the description thereof will be omitted here. Also, D in the drawing indicates the size of the pupil portion 41 obtained from the signal. When the brightness around the eyes is dark, the pupil diameter D is large, so that a red-eye state is likely to occur due to reflection on the retina and the pupil portion 41.
Is easy to obtain.

FIG. 5B is different from that of FIG.
In the case where the brightness around the eyes is bright, the pupil diameter D is shrunk to a small extent, reflected light in the red-eye state of the pupil part 41 is hardly obtained, and it is almost indistinguishable from the output of the iris part 42 and the white-eye part 43. . In such an output state, since the pupil center position cannot be specified, the line-of-sight direction cannot be calculated. FIG. 6 shows the optical axis 30 shown in FIGS. 4 (a) and 4 (b).
3 is an output example by the second light source 304 arranged on the first position.

FIG. 6A shows the case where the brightness around the eye is dark, the pupil diameter D is large, and the red-eye state due to reflection on the retina does not occur, or even if it occurs, it is very weak, so that it has a concave shape. The output is shown. However, since the periphery of the eye is dark, the concave output of the pupil portion 41 and the output of the iris portion 42 and the white eye portion 43 cannot be discriminated very clearly. Figure 6 (b)
In the case where the brightness around the eyes is bright, the pupil diameter is small because the pupil is contracted, and the range of the concave portion is narrower than in the case of FIG. 6A. However, the red-eye state due to reflection on the retina does not occur, or even if it occurs, it is very weak, and the brightness around the eye is bright, so that the pupil part 41 has a concave shape with respect to the output of the iris part 42 and the white-eye part 43. The output is clearly obtained. Therefore, the line-of-sight direction can be easily calculated. FIG. 7 is a flowchart showing an operation from power-on to exposure operation (release operation) at the time of photographing by the camera with a visual axis detection device described above, and the flow is executed by turning on the power.

STEP 701: It is judged whether or not the half-push switch SW1 is ON, and when it is ON, STEP
If it is not turned on, STEP 701 is repeated. STEP 702: Here, photometry is performed by the photometry unit 6. As an example thereof, photometry is performed for each area of the photographic screen divided into a plurality of areas, and each photometric value is stored in the storage unit in the control unit 1.

STEP 703: Here, the distance measuring unit 4 performs distance measurement calculation. As an example, as shown in FIG. 8, distance measurement is performed for each of the distance measurement areas A1, A2, and A3 in the finder 801, and each distance measurement value is stored in the storage unit in the control unit 1. STEP 704: Here, a visual axis detection subroutine for performing the visual axis detection operation is performed. Although details will be described later, in this embodiment, the line-of-sight direction is calculated from the Purkinje 1 image position and the pupil center position described in the related art.

STEP 705: Here, STEP 704
Based on the line-of-sight direction calculated in
Control of photometry and distance measurement is performed using the information obtained in EP703. As an example, the distance measurement control is calculated based on the distance measurement information of the distance measurement area A1 corresponding to the line-of-sight position indicated by the cross mark. Then, the photometric control performs a calculation by a weighted addition average having the area corresponding to the line-of-sight position indicated by the cross as the center of gravity.

STEP 706: Here, STEP 705
The photographing lens 201 is driven and focused based on the distance measurement information determined in. STEP 707: It is determined whether or not the full-push switch SW2 is ON, and when it is ON, the process proceeds to STEP 708, and when it is not ON, STEP 707 is repeated.

STEP 708: Here, STEP 705
Based on the photometric information determined in step 1, the exposure unit 8 performs a series of exposure operations such as mirror up, shutter running, mirror down, film feeding, and shutter charging. When the exposure operation ends, a series of operations ends. In addition, ST
After EP708 ends, the routine may return to STEP701 and continue execution of this routine until the power is turned off. Next, the visual axis detection subroutine will be described with reference to the flowchart of FIG.

STEP 901: Here, it is determined whether or not the brightness around the eyes is a predetermined value or more. If it is a predetermined value or more, the process proceeds to STEP 902.
Proceed to EP903. In the present embodiment, the brightness is measured by using the output of the photometric unit 214 of the camera, and the predetermined value is set such that the photometric value at the center of the screen is EV8. The setting of the predetermined value is not limited to this example, and it goes without saying that various settings can be made.

STEP 902: Here, STEP 901
Since the brightness around the eye is equal to or more than the predetermined value, the line-of-sight detection is performed in order to easily calculate the line-of-sight direction by obtaining the output signal of the photoelectric conversion element 213 as shown in FIG. 6B as described above. The second light source 304 is selected as the light source for use, the line-of-sight detection is performed, and the line-of-sight direction is calculated in STEP904. The light source is selected by the control unit 1 controlling the light source switching unit 2 based on the output of the photometric unit 214.

STEP 903: Here, STEP 901
Since the brightness around the eye is less than or equal to the predetermined value, the line-of-sight detection is performed in order to easily calculate the line-of-sight direction by obtaining the output signal of the photoelectric conversion element 213 as shown in FIG. The first light source 303 is selected as the light source for use, the line-of-sight detection is performed, and the line-of-sight direction is calculated in STEP904. STEP904: Here, STEP902 or ST
The P1 image position P and the pupil center position d are detected from the output signal of the photoelectric conversion element 213 obtained in EP903, and the control unit 1 calculates the line-of-sight direction using this. To calculate the line-of-sight direction θ

[0031]

## EQU00001 ## .theta. = Sin-1 ((d-P) / (A-.rho.)). However, A: the distance from the center of rotation of the eyeball to the center of the pupil, ρ: the distance from the center of rotation of the eyeball to the center of curvature of the cornea, the gaze direction θ is calculated by the above equation, and the gaze detection subroutine ends.

FIG. 10 shows another embodiment of light source selection in the line-of-sight detection subroutine. Here, instead of the light source switching unit 2 selectively switching between the first light source and the second light source, the light source switching unit 2 is used. A light source moving unit (a device using a motor, a device using a switching lever, or any other device capable of moving a light source) may be provided (the light source switching unit 2
(Included in 1)), the detection light source is switched by moving one light source to the first light source position and the second light source position. Therefore, the description of the flow is omitted.

In the present embodiment, the photometry unit 6 for measuring the brightness around the eyes is also used as the photometry unit of the camera.
It goes without saying that a photometric unit for measuring the brightness around the eyes may be provided separately from the photometric unit of the camera. In this case, any photometric unit may be used as long as the brightness can be measured.

[0034]

As described above, according to the present invention, the brightness around the eye is measured, and when the brightness is equal to or higher than a predetermined value, a predetermined tilt is obtained with respect to the observation optical axis (camera finder optical axis). Since it uses a line-of-sight detection light source arranged on the axis, the pupil part looks black with almost no reflection from the retina, and the output of the photoelectric conversion element due to the reflected light from the pupil part from the iris part and the white eye part. The output of the photoelectric conversion element due to the reflected light is lower than that of the photoelectric conversion element, and the pupil portion can be clearly discriminated from the iris portion and the white eye portion, so that the line-of-sight direction can be calculated easily and surely. In addition, when the brightness around the eyes is less than a predetermined value, a light source for line-of-sight detection arranged on an axis equivalent to the observation optical axis (camera finder optical axis) is used, so that the pupil is reflected by the retina. The area becomes red-eyed and appears bright, and the output of the photoelectric conversion element due to the reflected light from the pupil part becomes higher than the output of the photoelectric conversion element due to the reflected light from the iris part and the white eye part, and the pupil part and the iris part and the white eye part are separated. Since the distinction can be made clearly, the gaze direction can be calculated easily and surely.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a visual axis detection device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a camera with a visual axis detection device according to a first embodiment of the present invention.

FIG. 3 is a diagram showing details of a line-of-sight detection device unit.

FIG. 4 is a diagram showing an output example of a photoelectric conversion element.

FIG. 5 is a diagram showing an output example of a photoelectric conversion element.

FIG. 6 is a diagram showing an output example of a photoelectric conversion element.

7 is a diagram showing a flow of the camera with the line-of-sight detection device of FIG.

FIG. 8 is a diagram showing an AF area of a finder.

9 is a diagram showing a subroutine of line-of-sight detection in FIG.

FIG. 10 is a diagram showing another subroutine for line-of-sight detection in FIG.

[Explanation of symbols]

 1 ... Control part 2 ... Light source switching part 3 ... Illumination part 4 ... Distance measuring part 5 ... Light receiving part 6 ... Photometric part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03B 13/02 7139-2K 7316-2K G03B 3/00 A

Claims (3)

[Claims] 1. An illuminating means comprising a plurality of light sources for illuminating the eye of the photographer, a light receiving means for receiving reflected light from the eye illuminated by the illuminating means, and a brightness around the eye of the photographer. For measuring the light source, a light source switching unit for switching the plurality of light sources, an operation of the illumination unit, the light receiving unit, the photometric unit, and the light source switching unit, and at the same time from the light receiving unit. A camera with a line-of-sight detection device, comprising: a control unit that calculates a line-of-sight direction based on an output. 2. The camera with a line-of-sight detection device according to claim 1, wherein the plurality of light sources are a first light source arranged on an optical axis equivalent to a finder optical axis of the camera, and the finder optical axis. A camera with a line-of-sight detection device comprising a second light source arranged on an axis having a predetermined inclination. 3. The camera with a line-of-sight detection device according to claim 1, wherein the photometric unit for measuring the brightness around the eye also serves as the photometric unit of the camera. camera.