JP2993089B2 - Optical equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a gaze detecting means for detecting a gaze of a user,
The present invention relates to an optical apparatus having focus information forming means capable of forming information for focus adjustment for a plurality of focus areas.

(Prior Art) Conventionally, the gaze direction of a photographer is detected, and which region (position) in the viewfinder visual field the photographer is observing, so-called gaze direction of the photographer is provided in a part of the camera. Various cameras have been proposed in which various types of photographing functions such as automatic focus adjustment and automatic exposure are controlled based on a signal detected by the visual axis detection means.

For example, Japanese Patent Application Laid-Open No. 61-135135 proposes a camera that mechanically controls a distance measurement direction of a focus detection device based on an output signal from a line-of-sight detection unit to adjust a focus state of a photographing system. I have.

In addition, the present applicant discloses in Japanese Patent Application Laid-Open No. 1-241511, a line-of-sight detecting means for detecting a gaze direction of a photographer, a focus detecting means having a plurality of distance measuring fields, and an automatic exposure control having a plurality of photometric sensitivity distributions. And a camera that controls the driving of the focus detection unit and the automatic exposure control unit based on an output signal from the line-of-sight detection unit.

Whereas conventional cameras automatically set shooting conditions such as focus adjustment and exposure control based on the center area in the viewfinder visual field, the camera proposed in the publication discloses an arbitrary area in the viewfinder visual field. (There may be many areas) based on the photographer's intention, and focus adjustment, exposure control, and the like are performed in that area. Thus, it is possible to take a picture under free conditions intended by the photographer, separately from the method of automatically controlling the composition, which is the most important factor in drawing.

(Problems to be Solved by the Invention) Conventionally, automatic focus detection methods used in cameras include:
Broadly speaking, there are two types: a passive system that uses natural light coming from a subject, and an active system that projects light from the camera side to the subject side and uses reflected light from the subject.

Among the passive methods, there are a contrast detection method in which the sharpness of a subject image is grasped and a correlation method in which a coincidence determination of a double image of a subject is photoelectrically detected based on the principle of triangulation. In this passive method, in any method, the light amount distribution on the object surface is grasped, and then the image analysis is performed to perform focus detection. Therefore, if the object has extremely low brightness or extremely low contrast, image analysis is performed. Therefore, there was a tendency that a sufficient light quantity distribution pattern as a basis of the method could not be obtained, so that focus detection could not be performed or detection accuracy deteriorated.

On the other hand, in the active method, (a) if the reflectance of the object surface is low, the amount of reflected light is insufficient.

(B) If there is a high-luminance object around it, it will be difficult to discriminate it from the projected light component.

(C) As the subject distance increases, the reflection component of the projection light decreases.

For this reason, focus detection tends to be impossible or the detection accuracy tends to decrease.

As described above, in any of the focus detection methods, the focus detection may not be performed, or the detection accuracy may decrease.

For this reason, a focus detection area (distance measurement point) based on a signal of the photographer's gaze direction obtained by a line-of-sight detection means provided in the camera
Is set, a focus signal in that region may not be obtained, and even if obtained, the reliability may be poor.

In addition, when performing auto focus detection, detection cannot be performed.
Alternatively, there is also a subject pattern in which a large number of detection errors occur, so that when the gaze direction of the photographer is directed to such a subject, an accurate focusing signal cannot be obtained.

In addition, as a line-of-sight detection means, the photographer generally has a property of looking at the background and surrounding objects in addition to the main subject to be photographed. For this reason, the true gaze direction (gaze point) must be identified from the time course of the movement of the photographer's gaze direction. However, it is difficult to detect the line of sight depending on how the line of sight moves, and if there is a strong ghost or external light noise in the detection optical system, the line-of-sight detection accuracy decreases. For this reason, it is very difficult to detect the gaze direction in the finder visual field from the gaze direction.

On the other hand, in the automatic focus detection means of recent cameras, the range of the screen to be measured is not necessarily the entire area of the photographing screen, and a plurality of ranging fields are often set in a part of the area. In other words, since the main subject rarely comes to the edge of the screen, the area of the center excluding the edges of the four screens is 1/10 of the entire screen.
An automatic focus detection area is set in an area of about 1/2.

In the camera configured as described above, if the gaze direction of the photographer is out of the focus detection area, focus detection cannot be performed.

In a conventional camera, the target area for automatic focus detection is simply moved in accordance with the movement of the photographer in the line of sight. That is, even if a part of the focus detection unit or the line-of-sight detection unit becomes undetectable or a control mismatch occurs, no countermeasure is taken into consideration.

For this reason, there is a problem that even when the camera is provided with such a focus detection unit or a line-of-sight detection unit, these functions as a camera may not be sufficiently exhibited.

The present invention prevents a malfunction by prohibiting a focus adjustment operation based on a user's line of sight when the detection operation of the line of sight detection unit is impossible or it is determined that a highly reliable signal cannot be obtained. It is an object of the present invention to provide an optical device that performs

(Means for Solving the Problems) According to the invention described in claim 1, it is possible to form a line-of-sight detection unit that detects a line of sight of a user, and to form information for focus adjustment for each of a plurality of focus areas. Focus information forming means, selecting means for selecting one focus area from the plurality of focus areas based on the user's line of sight, and information for adjusting the focus of the focus area selected by the selecting means Focus adjustment means for performing focus adjustment based on, and determination means for determining whether gaze detection by the gaze detection means is possible or impossible,
When the gaze detection is determined to be impossible by the determination means, counting means for counting the number of times the gaze detection is determined to be impossible, and gaze detection is determined to be impossible by the determination means, and gaze detection is determined to be impossible. Prohibition means for prohibiting the focus adjustment operation based on the user's line of sight by the focus adjustment means when the number of times exceeds a predetermined number.

According to a second aspect of the present invention, there is provided a line-of-sight detecting unit that detects a line of sight of a user, a focus information forming unit that can form information for focus adjustment for each of a plurality of focus areas, and the user. Selecting means for selecting one focus area from the plurality of focus areas based on the line of sight, and focus adjustment for performing focus adjustment based on information for focus adjustment of the focus area selected by the selecting means. Means, determining means for determining whether there is a focus area corresponding to the user's line of sight detected by the visual line detecting means, and no focus area corresponding to the user's line of sight by the determining means If it is determined that the focus area corresponding to the user's line of sight does not exist Counting means, the number of times the focus area corresponding to the line of sight of the user is determined to be absent by the determination means, and the number of times that it is determined that the focus area corresponding to the line of sight of the user does not exist exceeds a predetermined number of times In this case, a prohibition unit for prohibiting a focus adjustment operation based on the user's line of sight by the focus adjustment unit is provided.

According to a third aspect of the present invention, in the first or second aspect of the present invention, there is provided a warning display unit for issuing a warning to the user in conjunction with the operation of the prohibiting unit.

(Embodiment) FIG. 1 is a schematic view of a main part of a first embodiment when the present invention is applied to a single-lens reflex camera, and FIG. 2 is an explanatory view of a part of FIG.

In the drawing, reference numeral 10 denotes an eyepiece lens, and 94 denotes an optical block, in which a dichroic mirror 95 that transmits visible light and is translucent to infrared light is obliquely provided, and also functions as an optical path splitter. 11 is a light receiving lens, 93 is a mirror, and 14 is a light receiving element array. The light receiving lens 11 and the photoelectric element row 14 constitute one element of the light receiving means. The photoelectric element row 14 is usually one vertical in the drawing.
Although a device in which a plurality of photoelectric elements are arranged in a two-dimensional manner is used, a device in which photoelectric elements are arranged in a two-dimensional manner is used as necessary.

Reference numeral 13 denotes a light source, which comprises, for example, an infrared light emitting diode. Reference numeral 91 denotes a light projecting lens, 7 denotes a focus plate, and a light dividing surface 92 is obliquely provided therein. The light splitting surface 92 is composed of a half mirror or a dichroic mirror.

In the figure, infrared light from a light source 13 is condensed by a light projecting lens 91, introduced into a focus plate 7, reflected by a light dividing surface 92, and incident on an eyepiece lens 10 via a pentaprism 8. The infrared light that enters and exits the eyepiece 10 passes through the dichroic mirror 95 and illuminates the eyeball 15 of the observer located near the eye point E. Further, the infrared light reflected by the eyeball 15 is reflected by the dichroic mirror 95 and converged by the light receiving lens 11 while being reflected by the mirror 93 to form, for example, a Purkinje image on the photoelectric element array 14 based on the reflection from the eyeball. Uses the signal from the photoelectric element array 14 to determine the gaze direction of the photographer's eyeball 15 and the gaze direction and gaze point in the viewfinder visual field.

The gaze detection method in the present embodiment is described in, for example, Japanese Patent Application Laid-Open Nos.
Since it is described in detail in Japanese Patent Publication No. 36 and the like and is not the gist of the present invention, the details are omitted.

In this embodiment, each of the above-described elements 10, 11, 13, 14, 91, 94, 10
1 constitutes one element of the visual line detection means. 1 is a photographing system (also referred to as a photographing lens), 2 is a quick return mirror, and 3 is a sub-mirror, which is fixed to the quick return mirror 2. 4 is a photosensitive surface (image surface) and 5 is a shutter. 6a is a focus detection means (focus information forming means),
It has a so-called multipoint focus detection function for detecting the in-focus state (focus information) of a plurality of positions (areas) in the finder visual field.

Reference numeral 102 denotes a selection unit, and a plurality of focus detection signals (based on a plurality of distance measurement areas transmitted from the focus detection unit 6a based on a signal regarding the gaze direction obtained by the calculation unit 101 which is an element of the gaze detection unit). One focus detection signal (focus signal) is selected from the focus signals.

103 is an adjusting means (focus adjusting means), and is a selecting means 1
The focus unit (not shown) of the photographing system 1 is driven based on the focus detection signal from 02 to adjust the focus state. Ten
Reference numeral 4 denotes a prohibiting unit, which prohibits the operation of the adjusting unit 190 depending on one of the output signal from the calculating unit 101 and the output signal from the focus detecting unit 6a, which is one element of the visual line detecting unit. doing. Reference numeral 105 denotes a light emitting unit, which includes a light source unit and a drive circuit, and turns on a display lamp and a warning lamp based on the operation of the prohibiting unit 104. Reference numeral 106 denotes a sounding unit that operates a sounding buzzer based on the operation of the prohibiting unit 104.

The focus detection method of the focus detection means 6a in the present embodiment is not the gist of the present invention, but employs a known technique. Therefore, only the outline thereof will be described below with reference to FIG.

Screen frame in the vicinity of the planned focal plane in FIG.
141 has five distance measurement fields 142a, 142b,..., 142e, and a known focus detection system is configured for each field. For example, in the figure, the image forming light beam that has passed through the rectangular field mask opening of the distance measuring field 142a at the left end is deflected by the left end lens of the integrally formed compound field lens 143, and a pair of secondary image forming lenses 144a ₁ and 144a ₂ Incident on.

A stop (not shown) is placed on the front surface of the secondary imaging lenses 144a ₁ and 144a ₂ . Light beam passing through the secondary imaging lens 144a ₁ is photoelectric device (hereinafter, the photoelectric conversion element is referred to such) reimaging optical image of the field of view 142a on the column 145a _1. on the other hand,
The light beam that has passed through the secondary imaging lens 144a ₂ is
reimaging optical image of the field of view 142a on a _2. A stop (not shown) in the vicinity of the above-described secondary imaging lens is substantially imaged on the exit pupil of the photographing lens by a field lens. As a result, a so-called pupil division focus detection device is constituted by the optical system. Five members are provided, and members that can be manufactured integrally are structurally integrated.

The concept of such a focus detection device is a known technology,
The figure shows a plurality of such technologies arranged side by side. A known technique is also used to calculate and determine the defocus of the photographing lens 1 from the output signal of the photoelectric element array.

Normally, the signal from the photoelectric element array is output serially,
Input to A / D conversion port of microcomputer.
The microcomputer in the camera sequentially converts the serial signal into an A / D signal at an appropriate timing and stores it in a memory.
When the reading of the serial signal is completed, the similarity of the light amount distribution pattern of the two images formed by the pair of secondary imaging lenses is calculated by a correlation operation, and the defocus of the photographing lens 1 is detected.

In this embodiment, the microcomputer used for the focus detecting means and the microcomputer used for the visual line detecting means may be commonly used, or may be different hardware operating in association with each other. Since the present invention describes a methodology of the mutual relation between the focus detection calculation and the eye gaze detection calculation, it is premised on hardware capable of controlling the whole under a unified flow.

Next, each operation of the first embodiment shown in FIG. 1 will be described with reference to the flowchart of FIG.

First, when a half-pressed state or a fully-pressed state of the release button is detected in a switch (SW) state detection routine (001), the flow proceeds to step (002) and the subsequent steps to detect a gaze direction of the photographer. Generally, the photographer's gaze focuses not only on the main subject to be photographed but also on the background and the periphery of the main subject, so it is necessary to statistically extract the intention of the photographer while following the movement of the gaze every predetermined time. .

That is, steps (002) to (004) show a process for detecting the line of sight once. In step (007), a gaze point (gaze direction) which is the photographer's will is determined based on these line of sight detections. The extraction is performed by a predetermined operation, and step (00)
The determination means determines whether or not the result of the operation extracted in 8) has the reliability used for controlling the camera.

If the result of the gaze calculation (step (003)) and the gaze point extraction (step (007)) are bad, the process returns to step (002) to accumulate the gaze data again.
Is counted in step (005), and if it is determined in step (006) that NG has been repeated more than a predetermined NO times, it is regarded as undetectable. Note that the simplest method of extracting and determining the gazing point is as follows.

The screen area corresponding to the finder visual field is divided into a finite number of small areas, and the distance measurement visual field is arranged at the center of each small area. For example, in FIG. 4A, small areas 146a to 146e and a small area 146f that does not include the distance measurement field are divided around five distance measurement fields 142a to 142e. According to the result of N times of eye-gaze detection, data of a predetermined ratio or more is concentrated in a specific one of the six small regions (146a to 146e), and if the number N is a predetermined value or more, the above-described specific The area is regarded as the area where the main subject exists (point of interest), and the distance measurement field of view located at the center thereof is extracted. Alternatively, if the area is a peripheral area of the small area 146f, it is determined that the area is outside the distance measurement range.

In general, the line of sight of the photographer's eyes rarely moves smoothly continuously, and often moves at points that are discontinuously separated. Therefore, by taking into account the time during which the line of sight stops at a certain point, a better intention can be extracted.

When the distance measurement fields are separated from each other as shown in FIG. 4 (B), it may be better to separate the small areas as well. In the distance measurement sequence of step (010), distance measurement is performed at the extracted gazing point. A step of determining whether or not the distance measurement data has accuracy sufficient to be used for focus adjustment control of the camera (01
The method in 1) is known. For example, the contrast of an optical image, the sum of squares of the difference between outputs of adjacent pixels, the shapes and similarities of two comparative optical images, or a combination thereof are often used as criteria for passive focus detection.

In the active focus detection, the magnitude of the reflected light signal is often used. In any case, distance measurement in the gaze direction of the photographer and its determination are performed based on the reliability determination of some distance measurement result. If it is determined that the distance measurement result is usable, the process proceeds to step (012) to determine the distance measurement point position and the distance measurement information selected based on the result.

Then, look at the state of the lens drive inhibition flag described later,
If it is in the reset state, the process proceeds to step (015), and the focus unit of the photographing lens is driven by the adjusting unit.

On the other hand, if it is determined in step (011) that the distance measurement point is selected based on the gazing point information and the result of the distance measurement does not have the accuracy (reliability) that can be used for camera control, and If it is determined in step (0) that the line of sight cannot be detected, or if it is determined in step (009) that the gazing point is outside the range to be measured, the lens drive prohibition flag is set in step (013). If it is detected in step (014) that the prohibition flag is set, a warning is displayed in step (016) and the lens is not driven for focusing.

As a warning method, for example, a sounding buzzer by a sounding means, blinking of a focusing display lamp by a light emitting means in a specific cycle, a color change, lighting of a warning lamp, or the like can be applied.
When step (016) is reached, lock in this state,
One way to compose a sequence is to monitor the state of the release switch so that it cannot escape unless there is a change.

In addition, after starting the warning device in step (016), NG
The sequence may be repeated by resetting the counter and returning to step (002). In this assembling method, even if the prohibition flag is raised for some reason, if the distance measurement point and the distance measurement information at that position can be determined in the sequence again, the prohibition flag reset operation is performed in this step. And can be configured to lead to lens driving.

In the present invention, the line of sight detection, the gaze point extraction, and the distance measurement operation may be continuous, and the temporal relationship may not be fixed and may be arbitrary. In other cases, operating in parallel may be desirable because the time required for camera control is reduced.

FIG. 5 shows the second embodiment of the present invention based on such parallel operation.
It is a flowchart figure of an Example. Next, the operation of the second embodiment shown in FIG. 5 will be described. In the switch (SW) state detection routine (021), the release button is half-pressed,
Alternatively, when the fully pressed state is detected, steps (022) to (023)
To detect the gaze direction of the photographer.

Next, in step (025), the gaze point (gaze direction) is extracted by the photographer's will by a predetermined calculation, and in step (026), it is determined whether or not the result of the extraction calculation has reliability that can be used for camera control. Is determined. If the determination result is NG, the process returns to step (022) via a counter operation (step (029) and step (030)) to accumulate the line-of-sight data again.

While the line-of-sight detection system repeats the above operation, the distance measurement system performs full-field distance measurement in parallel in steps (027) to (028). Since the sensors for receiving the light images in the respective visual fields are provided for each visual field, the photoelectric conversion operations of the sensors in all visual fields can be started simultaneously. In the subsequent signal processing calculation of the multi-point distance measuring system, the defocus amount or distance of each distance measuring point is measured by a known technique.

The determination of the gazing point extraction in step (026) is OK, and this gazing point is within the range to be measured and the step (02)
When the distance measurement up to 8) is completed, the accuracy and reliability of the distance measurement data in the gazing point direction are determined in step (032). If the determination result is OK, the distance measuring point position is determined in step (034). If the judgment result is NG, the process proceeds to step (033). In step (033), if the gaze direction (gaze direction) could not be detected, or if the gaze point was out of the range of the distance measurement, the gaze detection system and the focus detection system failed, or a mismatch occurred. At times, a lens driving prohibition flag is set.

After the processing of steps (033) and (034), step (03)
In step 5), the content of the lens drive prohibition flag is checked. If the flag has been reset, the process proceeds to step (036). In accordance with the content determined in step (034), the focus lens of the photographing lens is driven by the adjusting means for focusing. I do. The following sequence is not essential, but after the lens driving is completed, the distance is measured again (037), the focus is checked (038), and if it is in focus, the next sequence (not shown) such as display and AF lock operation is performed. If the focus has not been reached, the process returns to step (036) to perform lens drive for correction. This re-ranging sequence can be performed in the previous embodiment.

On the other hand, if the prohibition flag is set in step (035), the process proceeds to step (039) to display a warning or the like, and does not perform lens driving. As a warning method, as in the first embodiment, a sounding buzzer, blinking of a focusing display lamp in a specific cycle, a color change, lighting of a warning lamp, etc. are effective. When the step (039) is reached, one sequence is to lock in this state and to prevent the escape without excluding any change while monitoring the release switch state.

After starting the warning device in step (039),
It is also possible to reset the counter, return to step (002), and repeat the sequence. In this assembling method, even if the prohibition flag is set for some reason, the process returns to step (034) in the sequence again, and if the distance measuring point and the distance measurement information at that position can be determined, the prohibition flag is reset in this step. It can be configured to include an operation, and can be configured to lead to lens driving.

In each of the embodiments described above, the focus detection system is described as a passive system. However, the present invention has the same effect in an active multi-point distance measurement system.

Further, even when the two-dimensional imaging device for the TV screen and the light receiving means for the focus detection are shared as in the focus detection method used in the video camera, the screen is appropriately divided (the screen may be overlapped). By doing so, a multi-point focus detection system can be substantially configured, and the present invention can be effectively used in combination with a visual axis detection system.

(Effect of the Invention) As described above, the invention described in claim 1 is
When it is determined that the gaze detection is impossible and the number of times that the gaze detection is determined to be impossible exceeds a predetermined number, the focus adjustment operation based on the user's gaze is prohibited, thereby preventing an erroneous focus adjustment operation. Thus, it is possible to provide an optical device that performs a suitable focus adjustment operation.

In the invention described in claim 2, the number of times that it is determined that the focus area corresponding to the user's line of sight does not exist and the number of times that it is determined that the focus area corresponding to the user's line of sight does not exist exceeds the predetermined number of times In this case, since the focus adjustment operation based on the user's line of sight is prohibited, an erroneous focus adjustment operation can be prevented, and an optical device that performs a suitable focus adjustment operation can be provided.

[Brief description of the drawings]

FIG. 1 is a first view when the present invention is applied to a single-lens reflex camera.
FIG. 2 is an explanatory view of a part of FIG. 1, FIG. 3 is a flowchart of the first embodiment, and FIGS. 4 (A) and (B) are diagrams of a camera according to the present invention. FIG. 5 is a flow chart of a second embodiment of the present invention. In the figure, 1 is a photographing system, 10 is an eyepiece, 11 is a light receiving lens,
13 is a light source, 14 is a light receiving element array, 15 is an eyeball, 92 is a light dividing surface,
95 is a dichroic mirror, 4a is a photosensitive surface, 5 is a shutter, 6a is focus detection means, 101 is calculation means, 102 is selection means, 103 is adjustment means, and 104 is inhibition means.

Claims (3)

(57) [Claims] 1. A gaze detecting means for detecting a gaze of a user, a focus information forming means capable of forming information for focus adjustment for each of a plurality of focus areas, and a focus information forming means based on the gaze of the user Selecting means for selecting one focus area from the plurality of focus areas, and focus adjusting means for performing focus adjustment based on information for focus adjustment of the focus area selected by the selecting means. Determining means for determining whether or not gaze detection by the gaze detection means is possible; counting means for counting the number of times that gaze detection is determined to be impossible when the determination means determines that gaze detection is not possible; If the means determines that the gaze detection is not possible and the number of times that the gaze detection is determined to be impossible exceeds a predetermined number, the focus adjustment is performed. An optical apparatus, comprising a prohibiting means for prohibiting the focusing operation based on the line of sight of said user by stage. 2. A sight line detecting means for detecting a sight line of a user; a focus information forming means capable of forming information for focus adjustment for each of a plurality of focus areas; Selecting means for selecting one focus area from the plurality of focus areas, and focus adjusting means for performing focus adjustment based on information for focus adjustment of the focus area selected by the selecting means. Determining means for determining whether there is a focus area corresponding to the user's line of sight detected by the line of sight detection means; and determining that the focus area corresponding to the user's line of sight does not exist by the determining means In this case, a counter for counting the number of times that it is determined that the focus area corresponding to the user's line of sight does not exist. Means, it is determined by the determination means that the focus area corresponding to the user's line of sight does not exist, and when the number of times determined that there is no focus area corresponding to the user's line of sight exceeds a predetermined number of times An optical device comprising: a prohibition unit for prohibiting a focus adjustment operation based on the user's line of sight by the focus adjustment unit. 3. The optical apparatus according to claim 1, further comprising a warning display unit that issues a warning to the user in conjunction with the operation of the prohibition unit.