JP3239396B2 - Camera having focus detection means and line-of-sight detection means - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having a line-of-sight detecting means and a focus detecting means.

[0002]

2. Description of the Related Art Conventionally, the gaze direction of a photographer is detected, and what area (position) in the viewfinder field the photographer is observing, that is, the 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. 61-61135 discloses a camera that mechanically controls the distance measurement direction of a focus detection device based on an output signal from a line-of-sight detection means to adjust the focus state of a photographing system. Proposed.

Further, the applicant of the present invention disclosed in Japanese Patent Application Laid-Open No. 1-241511 has 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 a plurality of photometric sensitivity distributions. There has been proposed a camera having automatic exposure control means, in which the drive of the focus detection means and the automatic exposure control means is controlled based on the output signal from the visual line detection means.

In a conventional camera, photographing conditions such as focus adjustment and exposure control are automatically set with reference to a central region in a viewfinder visual field. An arbitrary area (in some cases, a large number of areas) is selected based on the photographer's intention, and focus adjustment, exposure control, and the like are performed in the selected 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.

In general, in a camera having an automatic focus detecting means, a method of controlling the signal processing (A) relating to the automatic focus detecting means and the signal processing (B) such as photometry and switch sensing as a series of flows is adopted. .

When such a camera is added with a line-of-sight detection function for controlling, for example, automatic switching of a plurality of distance measurement areas using information of the line of sight of the photographer, signal processing relating to automatic focus detection (A) The signal processing (B) such as photometry and switch sensing and the signal processing (C) for inputting the line-of-sight information are controlled as a series of flows.

[0008]

The signal processing (C) for inputting the line-of-sight information, the signal processing (A) for automatic focus detection, and the signal processing (B) for switch sensing, photometry and the like are repeatedly executed as a series of flows. In the sequence of the moving camera, the interval of each signal processing becomes longer as compared with the sequence of the camera without the line-of-sight detecting means. Therefore, the responsiveness of each function deteriorates.

For example, when the brightness of the subject becomes dark, the processing time of the focus detection control becomes longer, the processing interval of the line of sight detecting means is greatly delayed, and the responsiveness of the detection of the gazing point (line of sight) is reduced.

When the distance is measured by the focus detecting means based on the gazing point information obtained by the eye-gaze detecting means, the photographing is performed by the camera shake of the photographer observing the viewfinder image or the instantaneous picture of the photographer. There has been a problem that focus detection may not be performed with predetermined accuracy in a distance measurement area in the direction of the gazing point of the user.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a camera having a focus detecting means and a visual line detecting means capable of performing both the focus detecting operation and the visual line detecting operation quickly.

[0012]

According to a first aspect of the present invention, there is provided a visual line detecting means for detecting a visual line, a focus detecting means for detecting a focus state in a plurality of areas, the visual line detecting means and the focus detecting means. And control means for controlling the means to operate in parallel, and when the line-of-sight detection operation of the line-of-sight detection means ends earlier than the focus detection operation of the focus detection means, the control means The focus detecting means is controlled so that the focus detecting operation is limited to an area corresponding to the visual line obtained by the visual line detecting means. According to a second aspect of the present invention, in the first aspect of the present invention, when the region corresponding to the line of sight obtained by the line of sight detection unit is not focus detectable, the control unit is adjacent to the region corresponding to the line of sight. It is characterized in that the focus detection means is controlled so as to perform a focus detection operation of an area. According to a third aspect of the present invention, in the first or second aspect, when the focus detection operation of the focus detection means ends earlier than the visual axis detection operation of the visual axis detection means, the control means performs the subsequent focus detection operation. Is controlled until the eye-gaze detection operation is completed.

[0013]

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, FIG. 2 is an explanatory view of a part of FIG. 1, and FIG. 3 is a block diagram of a main part of the present invention. .

In FIG. 1, reference numeral 1 denotes an eyepiece, in which a dichroic mirror 1a for transmitting visible light and reflecting infrared light is obliquely provided, and also serves as an optical path splitter.

Reference numeral 4 denotes a light receiving lens, and 5 (5a, 5b (not shown), 5c) are illuminating means, which are composed of, for example, light emitting diodes. Reference numeral 6 denotes a photoelectric element row. Light receiving lens 4
And the photoelectric element array 6 constitute one element of the light receiving means. The photoelectric element array 6 normally uses a device in which a plurality of photoelectric elements are arranged one-dimensionally in the direction perpendicular to the drawing, but uses a device in which the photoelectric elements are arranged two-dimensionally as necessary. Each element 1,
The eyeball gaze detection system (gaze detection means) is constituted by the eyeballs 4, 5, and 6.

Reference numeral 11 denotes a photographing lens, 2 denotes a quick return (QR) mirror, 3 denotes a display element, 14 denotes a focus plate, 15
Is a condenser lens, 16 is a penta roof prism, 7 is
Is a sub-mirror, and 8 is a focus detection device (focus detection means) capable of multi-point distance measurement, and performs focus detection by selecting a plurality of regions in a shooting screen.

As shown in FIG. 2, the focus detecting device 8 is arranged near a predetermined image forming plane of the photographing lens 11 and has a field mask 20 having a plurality of slits each of which determines a distance measuring area. A lens member 21 that functions as a field lens is arranged in close proximity, and a set 22 of re-imaging lenses and a set 23 of photoelectric element arrays are arranged in order according to the number of slits. Slit 20, field lens 21, re-imaging lens set 2
2, and the set 23 of photoelectric element arrays respectively constitute a well-known focus detection system.

In this embodiment, a part of the subject light transmitted through the photographing lens 11 is reflected by the QR mirror 2 to form a subject image near the focus plate 14. The subject light diffused on the diffusing surface of the focus plate 14 is guided to the eye point E via the condenser lens 15, the penta roof prism 16, and the eyepiece 1.

Here, the display element 3 is, for example, a two-layer type guest-host type liquid crystal element that does not use a polarizing plate, and displays a distance measurement area (focus detection position) in a finder visual field.

A part of the subject light transmitted through the photographing lens 11 is transmitted through the QR mirror 2, reflected by the sub-mirror 7, and guided to the above-mentioned multi-point focus detecting device 8 arranged at the bottom of the camera body. Further, based on the focus detection information of the position on the subject plane selected by the multipoint focus detection device 8, the taking lens 11 is extended (or retracted) by a taking lens driving device (not shown), and the focus is adjusted.

The line-of-sight detecting device according to the present embodiment
A line-of-sight detection system composed of members represented by 4, 5, and 6, and an eyeball optical axis detection circuit, an eyeball discrimination circuit, a visual axis correction circuit, and a gazing point detection circuit included in the signal processing circuit 9 serving as an arithmetic unit And so on.

The gaze detection method in this embodiment is described in detail in, for example, Japanese Patent Application Laid-Open Nos. 1-241511 and 1-274736 proposed earlier by the present applicant.

That is, the infrared light emitted from the infrared light emitting diode 5 enters the eyepiece 1 from above in the figure, is reflected by the dichroic mirror 1a, and illuminates the eye 17 of the observer located near the eye point E. . The infrared light reflected by the eyeball 17 is reflected by the dichroic mirror 1a and converged by the light receiving lens 4 to form an image (such as a Purkinje image) on the photoelectric element array 6. The signal processing circuit 9 is executed by software of a microcomputer.

The gazing point information detected by the gazing point detecting circuit is first transmitted to the display element 3 and the multipoint focus detecting device 8. The display element 3 displays the place watched by the observer in the viewfinder of the camera and displays the point of gaze (focus detection point).
It plays the role of confirming.

In the multipoint focus detection device 8, the focus adjustment is performed on the gazed subject at the point gazed by the observer according to the flow described later.

Next, the basic operation of the present invention will be described with reference to the block diagram of FIG.

In FIG. 3, reference numeral 35 denotes a line-of-sight detection unit which detects the line of sight of the observer. Reference numeral 36 denotes a sub-microprocessor unit (SPU) including a line-of-sight calculation circuit, which obtains line-of-sight information from a line-of-sight detection unit 35.

Reference numeral 34 denotes a microprocessor unit (M) including a photometric operation circuit, a distance measurement operation circuit (focus detection circuit), and the like.
PU), and obtains information from the photometric sensor 32 and the focus detection unit 30 via the interface 31, for example.

The MPU 34 and the SPU 36 exchange signals as needed. Reference numeral 33 denotes a switch for performing various photographing operations of the camera. That is, the first switch (SW1) of the release switch (not shown)
The MPU 34 outputs the signal and the second signal of the second switch (SW2).
Is being entered.

Next, various operations of the present invention will be described with reference to the flowcharts of FIGS.

FIGS. 4 to 6 show flowcharts for mainly performing AE control and focus detection control, and FIG. 7 shows a flowchart for mainly performing line-of-sight detection control.

First, when a signal of a basic operation is input to the camera and power is supplied to the circuit of each element in FIG. 3, the microprocessor unit (MPU) 34 operates in step 1 in FIG.
Execution starts from 01. At the same time, the sub-microprocessor unit (SPU) 36 starts executing from step 201 in FIG. At this time, the microprocessor unit (MPU) 34 and the sub-microprocessor unit (SPU) 36 independently control each other.

First, a microprocessor unit (M
The control of the PU (PU) 34 will be described with reference to the flowcharts of FIGS. In step 101 of FIG. 4, the state of the first switch SW1 which is turned on by pressing the release button of the switch means 33 in the first stage is detected, and if it is off, step 101 is repeatedly executed until it is turned on. If the first switch SW1 is on, step 102
Move to.

In step 102, a command for executing the line-of-sight detection is output to the sub-microprocessor unit (SPU) 36, so as to perform the line-of-sight detection. Sub microprocessor unit (S
The execution of the (PU) 36 will be described later.

Next, the routine proceeds to step 103, where the flag S
Clear ELAFNG. This flag SELAFNG
Is a flag indicating that the distance measurement cannot be performed with a predetermined accuracy in the selected distance measurement area and the distance cannot be measured. Next, the routine proceeds to step 104, where the line-of-sight detection end flag is cleared. This flag is set to S
This flag indicates that distance measurement area information has been input from the PU 36.

Next, the routine proceeds to step 105, where a subroutine "AE control" is executed. This subroutine "AE
In the "control", control such as photometry, detection and display of a switch state, and the like are performed. Since these do not directly relate to the present invention, detailed description will be omitted.

Next, in step 106, an accumulation operation of an AF sensor (focus detection sensor) is started to perform focus detection. In the next step 107, the eye-gaze detection end flag is checked. If the flag is 1, the flow proceeds to step 112 because the distance measurement area information has already been input. If the flag is 0 in step 107, since the distance measurement area information has not been input yet, the flow shifts to step 108 to determine whether or not the line-of-sight detection being processed by the SPU 36 has been completed. If the gaze detection has not been completed, the process proceeds to step 112. If the line-of-sight detection has been completed, distance measurement area information based on the line-of-sight detection is input from the SPU 36.

In step 109, the eye-gaze detection end flag is set to 1 and the fact that the distance measurement area information has been input is stored. In the next step 110, a signal requesting the SPU 36 to communicate the ranging area information is output. Next step 111
Then, distance measurement area information is input from the SPU 36.

Next, in FIG. 5, in step 112, it is checked whether or not the sensor in one of the plurality of ranging areas has completed accumulation, and if there is no sensor that has just completed accumulation, the process proceeds to step 107. If there is a sensor whose accumulation has just been completed, the process proceeds to the next step 113, and an image signal of the subject in the ranging area is input.

Next, at step 114, the defocus amount is calculated based on the image signal of the subject by a known method. Detailed description of the process for obtaining the defocus amount is omitted here. Next, in step 115, the gaze detection end flag is checked. If the flag is 0, the flow proceeds to step 116;
Move to 7.

In step 116, it is determined whether or not the defocus calculation has been completed for all the distance measurement areas.
If there is any ranging area for which the defocus calculation has not been completed yet in step 116, the process proceeds to step 107. If the defocus calculation has been completed for all the ranging areas, the process proceeds to step 120.

In step 117, it is determined whether or not the defocus calculation for the selected focus area has been completed. If not, the process returns to step 107. If it has, the process proceeds to step 118.

In step 118, it is determined whether or not the focus cannot be detected with predetermined accuracy by checking the focus state of the selected ranging area. If not, the flow proceeds to step 120. I do. If the distance measurement is not possible, the process proceeds to step 119, and the work of switching to the distance measurement area adjacent to the distance measurement area obtained from the point of gaze of the photographer is performed.

As a result, a stable operation can be performed even when the photographer's gazing point slightly moves due to, for example, a hand shake while the camera is being held or a momentary fluctuation of the photographer's gazing point. . Thereafter, the flow returns to step 107.

In step 120, the eye-gaze detection end flag is checked. If the flag is 0, the distance measuring area information has not been input yet, so the flow proceeds to step 121. If the flag is 1, the distance measuring area information has already been input. Step 12
Move to 4. In step 121, the process waits until the line-of-sight detection processing being performed by the SPU 36 ends. When the line-of-sight detection processing is completed, the process proceeds to step 122, and a request signal for communicating distance measurement area information to the SPU 36 is output.

Next, in FIG. 6, in step 123, the selected distance measurement area information obtained from the point of gaze of the photographer is input from the SPU 36. Next, in step 124, the defocus amount of the ranging area obtained from the point of gaze of the photographer is determined as the defocus amount to be finally controlled.

In the next step 125, it is determined whether or not the photographing lens is in focus.
Is displayed in step, and if it is not in focus, step 1
The process moves to 27 to drive the lens. When these processes are completed, the process returns to step 101 again.

Next, the control by the sub-microprocessor unit (SPU) 36 will be described with reference to the flowchart of FIG.

In step 201 of FIG. 7, step 201 is repeatedly executed until a command for starting the execution of the line of sight detection is input from the microprocessor unit (MPU) 34, and the command for starting the execution of the line of sight detection is executed. Is entered, the process proceeds to step 202,
The control of gaze detection is executed.

In step 202, the operation of accumulating the line-of-sight information input sensor is started. In step 203, the process waits until the accumulation of the line-of-sight information input sensor is completed. When the accumulation is completed, the process proceeds to step 204, where the sensor for inputting the line-of-sight information is read. Step 20
In step 5, an operation of obtaining the point of gaze of the photographer based on the output of the sensor for inputting the line-of-sight information is executed. In the next step 206, a distance measurement area corresponding to the gazing point of the photographer is determined.

In step 207, a signal indicating that the line-of-sight detection has been completed is output to the MPU 34, and in step 208, it waits until a communication request signal from the MPU 34 comes. MP
When a communication request signal is received from U34, in step 209, distance measurement area information obtained from the point of gaze of the photographer is output to the MPU. When these processes are completed, step 20
Return to 1.

[0052]

According to the first aspect of the present invention, both the focus detection operation and the line-of-sight detection operation can be performed at short intervals without greatly delaying the cycle of each detection operation. Performance can be improved. According to the second aspect of the present invention, the responsiveness of the focus detection means does not decrease even when the focus corresponding to the line of sight cannot be detected. According to the third aspect of the present invention, unnecessary focus detection operation is not performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of a first embodiment 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 main block diagram of the present invention.

FIG. 4 is a flowchart showing the operation of the present invention.

FIG. 5 is a flowchart showing the operation of the present invention.

FIG. 6 is a flowchart showing the operation of the present invention.

FIG. 7 is a flowchart showing the operation of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Eyepiece 4 Light receiving lens 5 Illuminating means 6 Photoelectric element array 8 Focus detecting means 9 Computing means 11 Shooting lens 30 Focus detecting unit 32 Photometric sensor 33 Switching means 34 Microprocessor 35 Eye gaze detecting unit 36 Sub-microprocessor

Claims (3)

(57) [Claims] 1. A line-of-sight detecting means for detecting a line of sight, a focus detecting means for detecting a focus state in a plurality of areas, and a control so that the line-of-sight detecting means and the focus detecting means operate in parallel. and control means for possess, the sight line detection
The line-of-sight detection operation of the output unit is the focus detection operation of the focus detection unit.
When the operation is completed earlier than the operation, the control means
The focus detection operation is performed on the line of sight obtained by the line of sight detection means.
A camera having a focus detection unit and a line-of-sight detection unit , wherein the focus detection unit is controlled so as to be limited to a corresponding area . 2. The method according to claim 1, wherein when the area corresponding to the line of sight obtained by the line of sight detection means cannot perform focus detection, the control means performs a focus detection operation for an area adjacent to the area corresponding to the line of sight. 2. The camera according to claim 1 , wherein said camera further controls said focus detecting means. 3. When the focus detecting operation of the focus detecting means ends earlier than the visual line detecting operation of the visual line detecting means, the control means does not perform the subsequent focus detecting operation until the visual line detecting operation ends. 3. The camera according to claim 1, wherein said focus detection means is controlled.