JP2763296B2 - Optical device having gazing point direction detecting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device which controls the operation by photoelectrically detecting a gazing point direction (a line of sight direction), and is particularly optically determined. Correct the deviation of the eyeball between the optical axis and the gazing point direction,
This is a significant improvement in operating performance.

[Conventional technology]

2. Description of the Related Art In recent years, with the rapid progress and reduction in cost of photoelectric conversion devices such as electronic circuits and CCDs, camera automation and intelligentization have been developed. For example, cameras with automatic focus control are widely used, regardless of whether they are silver halide cameras or video cameras, and most cameras have an automatic exposure function.

This kind of automatic function greatly improves the operability of the camera,
It can be said that this was a major advance in that anyone could take a certain level of photography without requiring advanced photography techniques.

However, on the other hand, there are cases where image quality is limited due to the hardware restrictions of automatic functions due to the introduction of automatic functions,
A drastic improvement is desired. The biggest problem is that both the automatic focus adjustment and the automatic exposure control are designed to function mainly at the center of the screen, so the framing of the main subject at the center of the screen increases. It is. In particular, the focus must be clearly aimed at the main subject, and the average of the entire screen is meaningless. Therefore, it is necessary to configure the main subject at the position where the automatic focus detection device operates. This is an essential requirement for photography.

In order to alleviate such restrictions on drawing, a method called focus lock is generally used. In this method, when the shutter is half-pressed, the main subject is placed at the center of the screen to perform automatic focusing, and when the camera reaches a focused state, the camera automatically locks the focusing mechanism. Next, the photographer changes the position of the main subject to an appropriate position in the screen while continuing the half-pressing state of the shutter, re-framing, and presses the shutter once again at the point where convincing is achieved.

A similar method is used even in the case of automatic exposure control, especially when the most important part of the main subject is spot-metered due to a large difference in subject luminance, and is called an AE lock or the like. Usually, a camera has a photometric sensitivity distribution in which the center of the screen is emphasized, and especially in a spot-like photometric mode, the sensitivity is only at the center of the screen. Therefore, after measuring the most important subject portion by the photometry function at the center of the screen, the composition is re-taken while the photometry value is stored in the half-pressed state of the shutter.

There are some basic problems with such a method, and in reality, it cannot be a sufficient automatic function of a camera that guarantees image quality. The problems are listed below.

(1) It is necessary to get used to the feel of the fingertip in order to examine the composition while continuing the shutter half-pressed state. Since the majority of camera users do not shoot so frequently that they operate the camera, the camera operation that requires such skill cannot be fully used.

(2) If the subject is moving in the depth direction of the scene, the above operation is impossible. This is because the focus position is changed while the automatic focus adjustment is performed and the composition is retaken with the shutter half-pressed. Even in the case of a subject that moves while maintaining the same distance from the camera in the lateral direction, rather than in the depth direction, high skill is required to accurately perform the above-described stepwise operation.

(3) For subjects whose facial expressions and poses change, such as humans and animals, the shutter is instantaneous, so that a photograph intended by the photographer cannot be taken by the above method.

(4) When the camera is fixed on a tripod or the like, it is practically difficult to adjust the angle while pressing the shutter halfway.

For the above reasons, a new attempt has been started in which the drawing ability is not restricted by the central distance measurement field of view or the spot photometry function. As for auto focus adjustment, the main measure is to select a focus detection device in which a plurality of auto focus detection points exist in a wide area on the screen, or to selectively designate a part of a wide focus detection field of view, and to be included in that part This is a camera that performs automatic focus adjustment based on subject information. Both are well known. For example, as the former focus detection device, a plurality of conventionally known focus detection devices may be arranged in one camera as shown in FIG. Usually, the latter part of the range-finding field can be easily specified by software by using the function of the microprocessor mounted on the auto-focus camera.

Briefly explaining the figure, in FIG. 18, five distance measurement fields 142a, 142b,.
There is a known focus detection system for each field of view. For example, the image forming light beam that has passed through the rectangular field mask opening of the distance measuring field 142a at the left end in the drawing is changed by the left end lens of the integrally formed composite field lens 143, and is transmitted to the pair of secondary image forming lenses 144a ₁ and 144a ₂ . Incident. It is assumed that an aperture (not shown) is placed on the front surface of the secondary imaging lens. The luminous flux passing through 144a ₁ is converted into a field of view 145a on a row of photoelectric elements (hereinafter, photoelectric conversion elements are referred to as such) 145a _1.
Is re-imaged. On the other hand, the luminous flux that has passed through 144a ₂ is
Reimaging optical image of the field of view 142a on the photoelectric element array 145a _2. The aperture (not shown) near the secondary imaging lens described above is substantially imaged on the taking lens exit pupil by the field lens,
The above-described optical system constitutes a so-called pupil division focus detection device. FIG. 18 shows a system in which five members are provided and members that can be integrally manufactured are structurally integrated.

In such a hardware configuration of the automatic focus detection system, a method of determining a distance measuring point can basically take the following two concepts.

(1) The photographer specifies the distance measuring point position to be focused on the camera. Switches and dials are known as the designation input means.

(2) Analyze subject information at each point where the camera can measure distance,
Alternatively, the distance measurement is performed further, and the distance measurement point is automatically determined according to a predetermined reference. For example, a camera that focuses on a subject located closest to the camera can be considered.

All of the above methods have problems and are not sufficiently improved techniques. Although the method of (1) in which the photographer determines the position of the camera is reliable, the input is troublesome, and the original simplicity of the automatic focus adjustment is impaired. In ordinary hand-held imaging, it is possible to perform imaging more quickly by using the above focus lock method than by performing automatic focus adjustment after inputting a position. Therefore, it is difficult to use it except when using a tripod or when shooting a moving object, etc., where the position of the distance measuring point has an essential advantage.

On the other hand, how to determine where the camera focuses is
It often does not reflect the photographer's intentions for drawing. Although the approach of the near side selection may be selected as one operation state, it seems difficult to cover various uses of the camera by such a determination method.

For the above reasons, the idea of manually inputting the intention of the photographer is reliable, but it tends to be complicated, and the automatic method using a camera is too strong in uniformity.

Japanese Patent Application Laid-Open No. 61-135135 discloses the idea that the camera slightly senses the line of sight of the photographer to determine the distance measuring point, but does not describe a method of detecting the line of sight.

On the other hand, the optical axis of the eyeball can be determined by connecting the spherical centers if the cornea and lens of the eyeball are regarded as spherical, but when actually observing an object, the macula on the retina and the anterior ocular segment The user is gazing at the extension of the line connecting the nodes (the line of sight), and there is some deviation between the line and the visual axis. For this reason, there is a concern that an erroneous operation in which the line-of-sight direction is finely measured and precise operation control is performed based on the measurement result.

The method of photoelectrically detecting the direction of the line of sight and using it for operation control of the apparatus can be applied to focus adjustment and direction adjustment of various observation apparatuses other than the camera having the automatic focus adjustment apparatus.

In addition, recent cameras have manual input means for controlling various functions other than the automatic focus adjustment and automatic exposure functions, and switches and displays are dispersedly arranged in various parts of the camera housing. However, a user who uses the camera less frequently often forgets the operation method and often uses only a part of the functions provided in the camera.

[Problems to be solved by the invention]

According to the present invention, anyone can reliably and easily perform a desired operation, and accurately detect the direction of the line of sight to move the operation precisely.

In order to achieve this object, the present invention provides a finder optical system for observing an object, detecting means for detecting the direction of the eyeball optical axis of an eye looking into the finder optical system, and an output of the detecting means. And means for forming information on the gaze direction by performing a correction corresponding to the deviation between the direction of the optical axis of the eyeball and the gaze direction of the eye.

Furthermore, in view of the fact that the deviation between the eyeball optical axis direction and the gaze point direction differs from individual to individual, the gaze target is displayed in the field of view of the observation system, and the eyeball optical axis direction of the observer's gaze of the gaze target is displayed. A deviation in the direction of the gaze target is measured, and a correction value of the correction unit is determined.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment in which the present invention is applied to a single-lens reflex camera. The present invention can be applied to a single-lens reflex camera as well as a camera having a photographic optical path and a finder optical path separately.

In FIG. 1, reference numeral 1 denotes an objective lens, which is shown as a single lens for convenience. However, it is well known that the objective lens is actually composed of a large number of lenses. Reference numeral 2 denotes a main mirror which is inclined or retreated to a photographing optical path according to an observation state and a photographing state. Reference numeral 3 denotes a sub-mirror which reflects a light beam transmitted through the main mirror 2 downward from a camera body (not shown). 4a
Is a shutter used to expose a light-receiving surface of a photosensitive member described later for a predetermined time. Reference numeral 4b denotes a stop arranged in the objective lens 1, and 4c denotes a drive mechanism for moving the objective lens 1 in the optical axis direction for focusing.

Reference numeral 5 denotes a photosensitive member, which is a silver halide film, a solid-state image pickup device such as a CCD or MOS type, or an image pickup tube such as a Vitaicon.
However, if the electronic imaging device has an electronic shutter function, the shutter can be omitted.

6a is a focus detection device, for example, as shown in FIG.
Field lens 20, perforated field mask 21, 2 positive lenses
A secondary imaging lens 22 arranged side by side and a light receiving device in which a plurality of pairs of photoelectric element arrays are arranged are arranged. In FIG. 1, the field lens is provided at a predetermined imaging plane position of the objective lens 1 near the sub-mirror 3. 2A is described in Japanese Patent Application No. 62-315490. First, the slits 21a, 21b, and 21c of the multi-hole mask 21 determine the respective distance measurement fields. The secondary imaging lens 22 is, for example, a slit.
A part of the object scene image defined by 21a is defined as a pair 23a of a photoelectric element array.
Re-image on 23b. Also, slit 21b or slit
The part defined by 21c is a pair of photoelectric element arrays 23c and 23d or 23e.
And re-image on 21f. The light receiving information of each pair of the photoelectric element arrays is read out as an electric signal and subjected to a correlation operation to calculate a value representing the focus adjustment state of the objective lens with respect to the subject within the distance measurement field of view determined by each slit. . It should be noted that the configuration of FIG. 18 can be adopted as the focus detection device, or a method as disclosed in Japanese Patent Application No. 61-160824 is used, and a pair of photoelectric element arrays longer than usual is used. The photoelectric element array may be electrically divided and a correlation operation may be performed using signals corresponding to the corresponding divided regions.

As described above, the focus detection device 6a can detect the focus at a plurality of positions in the field of view. Reference numeral 6b denotes an exposure value detection unit, which includes a photodetector capable of dividing an image forming lens and performing photometry.
The imaging lens conjugately connects the focusing plate 7 disposed on the predetermined imaging surface of the objective lens 1 and the light receiving device via an optical path in the penta roof prism 8. The light receiving surface of the light receiver is divided, for example, as shown in FIG. 3, and it is assumed that measurement can be performed for each divided region. The output of the light receiver is input to the microprocessor mp, and the weight can be changed so as to have a photometric sensitivity distribution centered on a plurality of center points.

Next, an eyepiece 9 is disposed behind the exit surface of the penta-dach prism 8 for changing the optical path of the finder.
Is used for observation of the focus plate 7. A Fresnel lens may be provided near or integrally with the focus plate. Ten
Is a light splitter for a line-of-sight detection system, which uses, for example, a dichroic mirror that reflects infrared light, and is provided in the eyepiece 9 here. 11 is a condenser lens, 12 is a light splitter such as a half mirror, 13 is an illumination light source such as an LED, and preferably emits infrared light (and near infrared light). The luminous flux emitted from the infrared illumination light source 13 is emitted along the finder optical path as, for example, parallel light with the power of the rear surface (viewer side surface) of the condenser lens 11 and the eyepiece lens 9. Reference numeral 14 denotes a photoelectric converter, which will be described in detail later. When the observer properly looks into the eyepiece 9, the rear surface of the eyepiece 9 and the anterior portion of the observer's eye with respect to the condenser lens 11, specifically, the vicinity of the pupil. It is in a conjugate position. That is, it is one method to arrange the photoelectric converter 14 conjugately with the vicinity of the eye point of the finder optical system (8, 9), and the imaging magnification is preferably 1 or less.

With the above configuration, the imaging light beam that has passed through the objective lens 1 is partially transmitted, and is split by the main mirror 2 into a finder light beam and a focus detection light beam. After passing through the main mirror 2, the focus detection light beam is reflected by the sub-mirror 3 and enters the focus detection device 6. The focus detection device 6 is, for example, three in the horizontal direction on the photographing screen of the focus plate 7 shown in FIG.
It has point focus detection points 19L, 19C, and 19R. At the time of photographing, the main mirror 2 is flipped up, the sub-mirror 3 is stacked on the main mirror and folded, and the shutter blades 4 are opened and closed to expose the film 5 for a predetermined time.

On the other hand, the finder light beam enters the penta roof prism 8 via the focus plate 7. However, a Fresnel lens or the like integrated with or separate from the focus plate may be provided in the vicinity of 8. The luminous flux is projected onto the observer's eye while enlarging and projecting the subject image on the focus plate 7 by the eyepiece 9 whose diopter is adjusted.
It is incident on 15.

The structure of the human eye includes a corneal surface 16a, a posterior corneal surface 16b, and an anterior lens surface 18.
a, it can be seen as a cemented lens with the posterior surface 18b of the lens as a cemented surface or interface, and the iris 17 is near the anterior surface of the crystalline lens.
FIG. 4 shows the standard shape of the human eye and the refractive index of each part. FIG. 5 shows one row in which this is a model eye.

In general, the direction of the optical axis X of the eyeball and the gazing point direction (gaze direction)
There is a certain deviation from Y. Normally, the gaze point direction Y is the macula B
And on the line connecting the anterior ocular node A. When the movement of the eyeball is detected photoelectrically, it is easy to detect the optical axis X of the eyeball by utilizing the axial symmetry of the eyeball optical system, but it is high unless the deviation from the direction of the gazing point is corrected. This is inconvenient when precision is required. The correction method will be described later.

The optical path of the line-of-sight detection system is as follows. The illumination light emitted from the infrared illumination source 13 passes through the half mirror 12, is collimated to some extent by the lens 11, is reflected by the mirror 10, and enters the finder optical path. The dichroic mirror that allows the light splitter 10 to transmit the visible range light coming from the subject and reflects the illuminating light in the infrared range also has a problem in terms of the lighting efficiency of the gaze detection system from the viewpoint of the brightness of the finder. Is also desirable. However, if an infrared light source with sufficiently high luminance is used, it is possible to design in anticipation of a decrease in illumination efficiency and use an ND half mirror instead.

The infrared illumination light introduced into the finder optical path passes through the rear surface of the eyepiece 9 and illuminates the observer's eyeball. One method is that the illumination light is substantially collimated when entering the eyeball so that the illumination condition is maintained even if the position of the observer's eye changes.
This can be realized by adjusting the power arrangement of each part so as to be realized by the power of the lens 11 and the power of the rear surface of the eyepiece 9 as a whole. Since the refractive index change at each interface of the human eye is as shown in FIG. 4, the illumination light is reflected in the order of the anterior corneal surface, the anterior and posterior lens surfaces, and the posterior corneal surface according to the magnitude of the refractive index change. . The position of the reflection image at each interface when the parallel light beam enters can be understood by performing paraxial tracking. These statues are called Purkinje statues,
Numbered sequentially from the anterior corneal first Purkinje image, second
It is called an image. Except for the third image, the three Purkinje images are concentrated on the third surface, that is, immediately after the anterior surface of the crystalline lens. From the consideration of the refractive index change, the first image, the fourth image, and the second image are arranged in this order. It is a strong reflection image. Since the illuminating light for forming these images is in the infrared wavelength range, it is not perceived by the eyes and does not hinder the observation of the finder image. For this, the illumination wavelength is
It is desirable that the length be longer than 700 nm, and if it is longer than 750 nm, human eyes will not perceive regardless of individual differences.

The light reflected by the observer's eye follows the reverse path,
The light is reflected by the half mirror 12 through the lens 11 and received by the photoelectric converter 14. It is desirable that a visible cut and infrared transmission filter be inserted in the optical path from the reflected light being separated from the finder optical path to being received by the photoelectric converter. This is because the corneal reaction light due to the visible light of the viewfinder image is cut, and only the reflection of infrared illumination light, which is significant as an optical signal, is photoelectrically converted. The photocathode is located at such a position as to form an image near the front surface of the crystalline lens of the observer's eye, that is, near the pupil with the full power of the lens 11 and the rear surface of the eyepiece 9.
Thereby, the light is received in a state where the first, second, and fourth images of Prekinje are formed, and the amount of reflected light is not necessarily weak.
Since the third image is defocused and light is diffused, it does not contribute much to the photoelectric conversion signal.

The operation principle of visual axis detection of the visual axis detection device of the present embodiment will be described below. In the apparatus shown in FIG. 1, the infrared illuminating light source 13 is used as a point light source, and is illuminated so as to emit light from a position on the focus plate 7 at the center of the screen, that is, a point optically equivalent to the position 19c in FIG. The position of the point light source 13 is adjusted. In this case, if the optical axis of the observation eyeball passes through the center of the screen, the illumination light source is on an extension of the optical axis of the eyeball. In addition, each Purkinje image is linearly arranged as a point image on the optical axis of the eyeball. View from the front near the eyeball pupil is 6th
The result is as shown in FIG. In the figure, 41 is an iris, 42 is a pupil, and 43 is an overlapping Prikinje image. The brightly illuminated iris is observed in a ring shape, and one bright spot in which the Purkinje images of the respective surfaces are overlapped at the center of the dark circular pupil 42 is observed. On the other hand, if the eyeball is rotating and the optical axis of the eyeball is directed to one of the left and right sides, the illumination light enters the eyeball optical axis obliquely, so each Purkinje image moves to a position eccentric from the center of the pupil. In addition, since the direction and amount of movement are different for each reflection surface, a plurality of Purkinje images 43, 44 and the like can be seen from the front. FIG. 6B corresponds to this state. If the observer's eye looks at a position further away from the center of the screen, as shown in FIG. 6 (c), the tendency becomes stronger, and if the observer's eye looks in the opposite direction, the moving direction of the Purkinje image is also reversed. These movements are summarized in a graph in FIG. The moving amounts of the first and fourth Purkinje images that become strong reflection images near the pupil with respect to the rotation angle of the observer's eye are shown. If the movement of these Purkinje images is captured photoelectrically, the direction of the visual axis can be detected.

The above gaze detection method needs to deal with the parallel movement of the eyeball. In general, the camera's viewfinder system is designed so that the entire screen can be seen if the pupil of the observer is within a certain allowable range with respect to the eyepiece opening position. In fact, it is known that if this tolerance is narrow, the positional relationship between the camera and the pupil must be accurately maintained, resulting in a camera that is extremely difficult to use. However, the position of the pupil within this allowable range, that is, the position of the Purkinje image can vary depending on the gaze detection device, and it is necessary to compensate for this. Although the method is not limited, it is easy to realize from an optical point of view, and the following method is considered.

The position of the center of the pupil is always detected, and the relative displacement of the Purkinje image with respect to the center of the pupil is converted into the amount of rotation of the eyeball optical axis. This method is easiest to perform directly, but since the edge of the pupil (that is, the boundary with the iris) must be surely grasped, a wide viewing range of the photoelectric conversion element is required.

The relative displacement of two or more Purkinje images is measured. In this case, a combination of the first image and the fourth image is easily detected as an object. The image formation position is near and can be measured on the same image plane,
This is because the fired image is relatively strong. Regardless of which method is used, the amount of eyeball rotation required to change the position where the observer sees on the focus plate is at most about ± 10 ° to 15 °,
The displacement of the Purkinje image due to this is at most ± 1 mm, whereas the relative translation amount between the eyeball and the camera is several times larger than that, so the movement of the line of sight with a simple differential sensor is It may not be able to follow. On the other hand, by using a photoelectric element array formed by integrating several photoelectric elements, the light amount distribution near the pupil of the observer's eye is measured and numerically analyzed so that it is not affected by the position of the eyeball or the pupil diameter. A line-of-sight detection device is configured.

In the application shown in FIG. 1, only a horizontal line-of-sight movement needs to be detected, so a simple configuration using a one-dimensional photoelectric element array is shown below. FIG. 8 is for explaining the method. As a result of ignoring the detection capability in the vertical direction, a photoelectric device having a vertically long shape as shown in FIG. Is almost insensitive to vertical translation or rotation of. However, a similar effect can be obtained by bonding a cylindrical lens before the row of photoelectric elements.

In FIG. 8, the first image of Purkinje glowing in the pupil 61.
When the fourth image 63 and the fourth Purkinje image 63 are received by the one-dimensional photoelectric element array 64 (photoelectric converter 14), a photoelectric output as shown in FIG. 8B is obtained. The high output values on both sides represent the iris. In the dark pupil portion, signals 65 and 66 corresponding to the first and fourth Purkinje images are obtained.

The pupil center is obtained from the position information of the edge portions 67 and 68.
Most Briefly At a edge portion, the position coordinates of the pupil center of the pixel number resulting output close to half of the iris portion and average i _1, i ₂ is given by _{i 0 = (i 1 + i} 2) / 2 . Since the position of the Brukinje first image is obtained from the maximum peak locally appearing in the pupil dark part, the relative position relationship between this position and the previous pupil center indicates
The rotation state of the eyeball, that is, the direction of the line of sight can be known from the relationship shown in the graph of FIG. In this case, the interpretation in FIG. 7 can be considered assuming that the center of the pupil forms the origin of the amount of movement of the Purkinje image. Assuming that it is fixed to the camera at the origin, almost only translation of the eyeball is required. Purkinje 4
The image is obtained as the second peak of the pupil dark portion, and the calculation may be performed using this position and the position of the previous first image. In this case, it is not always necessary to know the position of the pupil center. However,
Since the first and fourth Purkinje images differ in intensity by a factor of 10 or more, a photoelectric element array having a relatively high dynamic range is required.

However, the same effect can be obtained by detecting the center position from the edge of the iris (the portion covered by the cornea) instead of the pupil center. Using the iris to determine the center is highly accurate because the diameter of the iris does not change with the brightness of the outside world unlike the pupil, but it is necessary to be able to detect a wide range because the diameter becomes large .

As is clear from FIG. 8, it is insensitive to the direction orthogonal to the arrangement direction of the elements, but if it is composed of photoelectric elements which are too long in the direction perpendicular to the arrangement direction, the iris may be picked up and down depending on the position of the pupil. There is a limit to how long it can be. Therefore, when a plurality of photoelectric element arrays composed of elements having a relatively small vertical length are arranged in the vertical direction and the line of sight is detected only by the arrangement that has obtained the most appropriate output, it is insensitive in the vertical direction, and The detection device can always obtain a Purkinje image signal. Further, in the above-described detection only in the one-dimensional direction, a better signal can be obtained if the illumination light source is not a point light source but a slit. In this case, a line light source may be constituted by an LED, or an infrared transmission visible cutoff filter and a white light source may be arranged behind the slit.

The method described above is executed by the micro computer mc to which the output of the photoelectric converter 14 shown in FIG. 1 is input, and the focus detection value at the distance measurement position corresponding to the line of sight of the observer is obtained.
The output from the output 6a is calculated by the micro computer mc, and the driving mechanism 4c is driven according to the calculated value to focus the objective lens 1.

In this manner, a camera controlled by a line of sight according to the present invention that switches the distance measurement points for automatic focus detection according to the obtained line of sight direction. Since the position of the line of sight is determined continuously, it goes without saying that the control target is not limited to three points as shown in FIG. 2 (b).

Further, the output of the exposure detection unit 6b is signal-processed by the micro computer mc to determine an exposure condition that places emphasis on a position corresponding to the line of sight of the observer, and one of the shutter 4a and the aperture 4b is synchronized with the release operation. Both can be set.

When controlling a camera, even if multiple points can be measured by both automatic focus detection and automatic exposure control, only one of them can be used or both can be used at the same time according to the intention of the observer. . In addition to focus detection and exposure control, mode displays such as shutter priority, aperture priority, and program shooting are displayed at different positions in the viewfinder field. For example, according to the mode display visually recognized when the first step of the release operation is pressed. You can also shoot.

Hereinafter, a method of correcting the deviation between the optical axis direction of the eyeball and the gazing point direction will be described.

A simple method of correcting the deviation is to manually input a correction value or other information. However, in this method, it is one method to separately measure the deviation and input a correction amount corresponding thereto, but in general, the correction amount having the average diameter of the human eye is stored in a micro computer in advance. deep. The IP in FIG. 1 is an input device for these purposes. If the correction amount is known in advance, the value shall be input. Otherwise, it is necessary to distinguish between looking through the finder with the right eye and the left eye. input. This is because the position of the above-mentioned lateral spot is symmetrical between the left and right eyes, and the direction of the deviation is + or-. In the majority of human eyes, the deviation between the gazing point direction and the direction of the optical axis of the eyeball is about 5 ° to 7 °, but since it is obtained as anatomical knowledge, the accuracy ± 1 °
Detection of about 2 ° is possible.

Next, a method that takes individual differences into account will be described. When looking through the eyepiece 9, the distance measurement field marks 19C, 19R, and 19L of the focusing plate 7 shown in FIG. 2B can be seen. For example, the measurement field mark 19C at the center of the observation field is used. Prior to the measurement, the observer (the photographer of the camera) gazes at the ranging visual field mark 19C, and inputs a measurement start signal from the input device IP in that state.

The line-of-sight detection system operates as described above, measures the optical axis of the observer's eye, and adjusts the optical axis direction of the eyeball, for example, the displacement of the Purkinje first image with respect to the center of the pupil, or the difference between the Purkinje first image and the fourth image. Quantify as relative displacement. At this time, since there is a physiological characteristic that the human line of sight easily fluctuates, signal processing software such as adopting the direction of the optical axis of the eyeball which occurs most frequently within a certain period of time may be used.

The measurement result by the gaze detection system is a micro computer mc
It is stored in the storage element inside.

The recording element is preferably a non-volatile EEPROM or the like, but is not limited to this. For example, a battery with a battery backup may be used. By providing such an operation state, the visual axis direction can be obtained in a situation where it is determined that the observer is gazing at the center of the screen. At the time of framing for photographing, a gazing point on the screen is obtained by calculating a relative difference between the measured direction of the optical axis of the eyeball and the direction of the optical axis of the eyeball at the time of gazing at the center of the screen. In mathematical terms, for example, when the position of the first Purkinje image with respect to the pupil center point or the iris center point is x, the gazing point direction X is expressed as X = k (x−x ₀ ) (1) It is. Here x ₀ is the x when the observer gazes the screen center, and k is a proportional constant determined constants Fuainda system as a main factor.

Further, in order to enhance the detection accuracy, the following embodiment is preferably employed.

That is, a slight difference is generally caused between the detection result of the gaze detection system and the actual gaze direction of the observer. Therefore, it is effective to check the detection result and adjust any deviation.
If the deviation is large, it is better to detect again.

FIG. 9 (a) depicts the focus plate, and the observation visual field looks like this. 71 is a display mark indicating the detection result,
For example, the image is displayed using a liquid crystal display or an EL display laminated on a focus plate, or an optical display that illuminates the diffraction grating from the side. x ₀ is preset to an appropriate value. FIG. 9 (b) shows a part of the liquid crystal display. 73
a is a liquid crystal layer, which is sandwiched between a uniform transparent electrode layer 73b and a transparent electrode layer 73c arranged in a discontinuous line, and further a polarizing sheet 73d.
It is sandwiched between. Power can be sequentially supplied to the electrodes of the lower transparent electrode layer 73c to perform display.

The observer can look into the eyepiece lens 9 of the viewfinder system and observe the display mark 71. At this time, when the observer gazes at a desired subject (not shown) in the observation field, if the subject and the display mark 71 overlap, it is detected. Was accurate. However, if the display mark 71 is displaced from, for example, the subject or the center distance measurement mark position of the observer's subjective gazing point 72, there is an error in the detection, and therefore it is better to perform the adjustment. .

When measuring the correction amount, the distance measurement mark is used in the above-described example, but the display mark on the display may be displayed at the center of the screen, for example, and may be used. This will help keep your gaze on.

Observer recognizing position itself with gazing point, until the camera position detecting matches as gazing point, and the dial input device, by means such as switch changing the constants x ₀ of the formula (1). Observer may be fixed to where x ₀ if Mitomere the detection display position of the own subjective sight and camera match. The input means of x ₀ is operated by the resistance partial pressure of the constant voltage power supply as, for example, FIG. 10 (a), and AD conversion, may be associated to x _0, or digitally (b Like)
The contents of the register 81 for storing the x ₀ by two opposite directions of the switch up-may be down. In the case of the above-mentioned method, a display is required, but the point that the observer does not need to guarantee that the reference point is fixed at the time of measurement is advantageous in terms of ease of use.

The camera of the present invention performs high-precision gaze point detection,
The invention includes correcting an individual difference between a difference between an eyeball light direction and a gazing point direction. When the photographer changes, the amount of the above-mentioned shift is slightly different. Therefore, the above-mentioned gazing point display is effective as a foolproof measure against the shift. If the gaze point displayed by the camera overlapping the shooting screen is consistent with the subjective gaze point of the photographer, it is sufficient to continue using the point of interest. What is necessary is just to redo the correction value setting of. If the gazing point display appears during the gaze detection operation, the necessity of setting the correction value can be instantaneously determined and will not be forgotten.

As described above, when the position of the gazing point is not so strict, the deviation between the optical axis direction of the eyeball and the gazing point direction is a universal constant that does not depend on individual differences, and is fixed in the circuit, for example, in the form of a mask ROM. Is also good. In this case as well, the input point of gaze can be displayed to confirm the position.

Based on the gazing point position information of the observer's eye detected by the above method, for example, the three points 19L, 19C, 19R in FIG.
The automatic focus adjustment can be performed at one point, and the automatic exposure correction can be performed as described later. In the method of detecting the gazing point in the above method, the position can be detected continuously or with extremely fine pitch, so that the moving object is not limited to three points as shown in FIG.

Although the above gaze detection has been described only in the one-dimensional direction,
In order to detect the movement of the line of sight not only in one direction but also in two orthogonal directions, a photoelectric element array in which pixels close to a square are two-dimensionally arranged may be used. If a one-dimensional array including the Purkinje first image is selected for each of the vertical and horizontal directions, the line-of-sight positions in two orthogonal directions can be obtained by a method based on the center of the pupil. That is, as shown in FIG. 11, light images near the observer's eye and the pupil are formed on a two-dimensionally arranged photoelectric element array, and signals in the vertical and horizontal arrangements 91 and 92 in the figure may be used. A known CCD image sensor or MOS type image sensor can be used as the photoelectric element array, and selecting an array to be calculated vertically and horizontally using the position of the Purkinje first image as an intersection can be easily realized by a microcomputer. .

Also in the case of the present embodiment, the method for correcting the deviation between the optical axis direction of the eyeball and the gazing point direction is basically the same. That is, most simply, an average value of human anatomical data is used, and a shift correction amount is built in advance, and correction is performed in the detected optical axis direction of the eyeball. Set the fixation point direction to (X,
X = k (x−x ₀ ) (2a) Y = k (y−y ₀ ) (2b) where (x, y) is based on the center of the pupil or the iris. The position of the Purkinje first image, (x ₀ , y ₀ ) is (x, y) when the observer is gazing at the center of the screen.

In order to detect the gazing point direction more accurately, the correction amount (x ₀ , y ₀ ) is detected for each specific photographer. As a method, for example, detection of the visual axis direction when gazing at the center of the screen, or adjustment of the correction amount so that the gazing point detection position display matches the subjective gazing point of the photographer, etc. Method can be used.

In the above description, it has been assumed that the posture of the camera is always fixed. In order to guarantee the operation of the line-of-sight detection device under more general conditions, it is desirable to detect the amount of relative rotation between the eyeball and the camera about the visual axis of the observer's eye. The most standard situation for this rotational degree of freedom is
As shown in FIG. 12, the horizontal axis 101 of the observer's eye and the horizontal axis 102 of the camera are parallel to each other. Occur. Most typically, θ = ± 90 °. No.
In FIGS. 12 and 13, reference numeral 103 denotes a single-lens reflex camera using a penta roof prism, and 104 denotes an observer's eyeball for observing a field of view from a front eyepiece behind the penta roof prism.
As a result of the relative rotation between the eyeball and the camera in FIG. 13, the fixation point correction amount (x ₀ , y ₀ ) undergoes the following changes.

The correction value (▲ ▼, ▲
▼) may be calculated, and the observer's eye gaze point may be obtained from the visual axis measurement value by equation (2).

A general method for measuring θ is preferably a photoelectric method. For example, the position of the part of the eye such as the outer corner of the eye is imaged and measured with respect to the camera reference coordinates, thereby obtaining the horizontal axis 101 of the observer's eye.
Can be relatively determined. However, since the horizontal axis of the observer's eye is fixed and only the posture of the camera changes to select a shooting frame, the work of measuring the above θ should be replaced with detection of the posture of the camera with respect to the earth's horizon. Can be. For this purpose, as shown in FIG. 14, for example, utilizing the fact that the slider 113 connected to the weight 112 faces vertically downward, the posture is detected based on the angle between the reference of the variable resistor 111 and the slider 113. Detectors are used. Figure 114
Is a rotation center of the slider, and is an output terminal of a divided voltage.

On the other hand, a mercury switch 115 shown in FIG. 15 in which mercury 116 is sealed in a ring may be used. The location of the mercury 116 sealed in the ring 115 is determined by examining where there is electrical continuity between the adjacent contacts such as the contacts 117a and 117b, and thus the direction vertically downward is detected. If the attitude detectors shown in FIGS. 14 and 15 are incorporated in the camera body, the rotation of the camera can be determined. Therefore, the visual axis measurement value is corrected using the equation (3) according to the amount of rotation. Accurate gaze point detection is possible.

It goes without saying that the present invention is not limited in its use to a single-lens reflex camera. FIG. 16 shows an example in which the present invention is applied to an inverted Galilean type finder system. The viewfinder optical system basically includes a concave lens 121 and a convex lens 122, and is an afocal system having an angular magnification of 1 or less. Twelfth
In the embodiment shown in FIG. 9A, a block-shaped optical member 123 is disposed between a positive lens and a negative lens, and the finder optical system and the detection detection optical system are connected by a dichroic mirror or a half mirror 124. . The lens 125 collimates the light coming from the infrared illumination light source 127 and forms an anterior ocular segment reflected light on the light receiving surface of the photoelectric element array 128. 126 is a half mirror. The method of gaze detection is the same as that of the embodiment shown in FIG. FIG. 12 (b) shows an example in which the infrared illumination system and the detection optical system are separately arranged.

The present invention is suitably used in general for cameras having a finder such as a video camera and a still video camera in addition to a silver halide photographic camera. In particular, the present invention is extremely effective for a video camera that often captures a moving object.

The application of the camera having the visual axis detection system according to the present invention is not limited to the control of the automatic focusing. Generally, it can be used as input means for controlling the operation method of the camera. No.
FIG. 17 illustrates an example of a photometric sensitivity distribution within a screen of a photometric device for exposure control of a camera. In FIG. 5A, 5 is displayed in the screen.
Number of local photometric point are arranged S ₁ to S _5. By detecting the line-of-sight direction, it is possible to configure a camera that selects one of these five photometric points and controls the exposure based on the photometric output. The FIG. 17 (b) is are arranged extensive metering area P ₁ to P ₅ by the outside of the local photometric point. Consideration of both sides of the photometric information about the S ₂ when specifying S _2, for example viewing direction By calculating the amount V, it is possible to provide a photometric sensitivity characteristic having a spread centering on the gazing point.

Furthermore, the optical device can be configured as a will input means for any control method of the camera, such as designation of a shutter speed, an aperture value, operation of a power focus and a power zoom, multiple exposure control, and switching of various operation modes. is there.

〔The invention's effect〕

As described above, according to the present invention, the correct gaze direction is detected by grasping the displacement of the position of the anterior segment reflection image and correcting the deviation between the visual axis direction and the gazing point direction. , Automatic focus adjustment, automatic exposure control, and other operations can be controlled as desired by the photographer. The present invention provides a novel camera that simultaneously satisfies the simplicity, accuracy, and high speed of the automatic function and the degree of freedom in drawing by manual control. The embodiment of the present invention clearly shows an optical line-of-sight detection method for performing a high-precision line-of-sight detection in a viewfinder system while allowing a degree of freedom in the positional relationship between a camera and an observer's eye.

Also disclosed a camera configuration incorporating a gaze detection device in the camera as a device that is economical without compromising portability,
A new camera control method was presented. By using the camera of the present invention, it is possible to make full use of advanced automatic functions while accurately reflecting the intention of the photographer.

[Brief description of the drawings]

FIG. 1 is an optical sectional view showing an embodiment of the present invention. FIG. 2A is a perspective view showing a partial configuration, and FIG. 2B is a plan view. FIG. 3 is a plan view of a component. FIG. 4 is an explanatory view of a human eye. FIG. 5 is a sectional view of a model eye. FIG. 6 (a), (b),
(C) is a diagram showing a reflected image of the eye. FIG. 7 is a diagram showing movement of a Purkinje image. FIG. 8A is a diagram for explaining detection of a reflected image, and FIG. 8B is a diagram showing an output signal. Ninth
FIG. 1A is a plan view of a focus plate, and FIG. 1B is an enlarged sectional view.
10 (a) and 10 (b) are diagrams each showing an adjuster. FIG. 11 is a diagram for explaining two-dimensional detection of a reflected image. FIG. 12 and FIG. 13 are diagrams for explaining a change in the attitude of the camera. FIG. 14 and FIG. 15 are diagrams each showing a posture detector. No. 16
(A), (b) is an optical sectional view showing another example, respectively.
17 (a) and 17 (b) are plan views each showing a visual field. 18th
The figure is a perspective view showing a conventional example. In the figure, 2 is a main mirror, 3 is a sub-mirror, 6a is a focus detection device, 6b is a photometry device for exposure control, 7 is a focusing plate, 8 is a penta roof prism, 9 is an eyepiece, 10 is a light splitter, 11
Denotes a condenser lens, 12 denotes a light splitter, 13 denotes an illumination light source, and 14 denotes a photoelectric converter.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasuo Suda 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Tamagawa Office of Canon Inc. In-house (56) References JP-A-63-94232 (JP, A) JP-A-63-54145 (JP, A) JP-B 1-1190177 (JP, B2) (58) Fields investigated (Int. ⁶ , DB name) A61B 3/113 G03B 13/02 G02B 7/09

Claims (6)

(57) [Claims] 1. A finder optical system for observing an object, detection means for detecting a direction of an eyeball optical axis of an eye looking into the finder optical system, and a direction of the eyeball optical axis in an output of the detection means. An optical apparatus having a gazing point direction detecting device, comprising: means for performing correction corresponding to a deviation in the gazing point direction to form information on the gazing point direction of the eye. 2. A finder optical system for observing an object, a detecting means for detecting a direction of an optical axis of an eye of an eye looking into the finder optical system, and a display for displaying a gaze target in a field of view of the finder. Means, a deviation between the direction of the optical axis of the eyeball and the gazing point direction is detected using an output of the detection means when the eye gazes at the gaze target, and a correction corresponding to the deviation is output to the detection means. An optical device having a fixation point detection device, the correction means for outputting information of the fixation direction of the eye by performing the correction. 3. The gazing point according to claim 2, wherein said display means has means for displaying a gazing point of said eye based on information output from said correcting means. An optical device having a direction detecting device. 4. The apparatus according to claim 1, further comprising means for adjusting a correction value for the correction corresponding to said deviation of said correction means so that said display means displays the gaze point at the position of the gaze target. An optical device comprising the gazing point direction detecting device according to range (3). 5. The optical apparatus according to claim 2, wherein said correction means stores a correction value for said correction in an EEPROM. 6. An optical device having a gazing point direction detecting device according to claim 2, wherein said display means blinks and displays said gazing target.