JP3461392B2 - camera - 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 function of detecting a photographer's line-of-sight direction and determining which portion of a screen the photographer wants to photograph.

[0002]

2. Description of the Related Art Conventionally, in an image pickup device such as a camera, it has been difficult to determine which part of the viewfinder the user is looking at.
Various techniques have been proposed which are judged from the direction of the user's line of sight and are used as a reference for selection of so-called multipoint AF.

For example, US Pat. No. 4,574,314 proposes a technique for focusing on a subject existing in the direction the photographer is looking. According to such technology,
By combining the line-of-sight direction detection unit and the distance measurement unit that can change the distance measurement direction, the person can be correctly focused even in a composition in which the person who is the main subject is not in the center of the screen as shown in FIG. 4A, for example. A camera can be provided.

In addition to this, a technique has been proposed in which a plurality of points on the screen are measured, that is, a subject showing the closest distance is focused on the basis of the distance measurement result of each point by multipoint AF. .

[0005]

However, in the above-mentioned U.S. Pat. No. 4,574,314, a television camera is used to detect the line-of-sight direction, and the structure is complicated and expensive. Furthermore, in the multi-point AF with the closest selection, it is possible to focus on the person of the main subject in a scene where the main subject is not in the center of the screen as shown in FIG. 4A, but the scene as shown in FIG. Then, there was a drawback that you couldn't focus on the person in the center of the screen.

[0006] Further, the gaze direction is detected due to a large difference in conditions such as individual differences in the eyes of the photographer and the presence or absence of use of eyeglasses.
It can be very difficult in some situations. Therefore, it is necessary to devise a design that does not affect the photographic screen even if the reliability becomes low.

The present invention has been made in view of the above problems, and an object thereof is to provide a camera capable of taking a photograph in which a main subject is correctly focused in any scene with a simple structure. .

[0008]

In order to achieve the above object, according to a first aspect of the present invention, in a camera capable of detecting distance measurement data of a plurality of points including a center in a photographing screen, If the photographer determines that the photographer is gazing at the central portion of the screen, the visual line detection means that detects only whether the photographer is gazing at the central portion of the viewfinder screen or not Select the distance measurement data of
When it is determined that the center portion of the screen is not being gazed at, the selection means for selecting one distance measuring data from the distance measuring data of the plurality of points is provided according to a predetermined criterion. A camera is provided. According to a second aspect of the present invention, in the first aspect, the predetermined judgment group
Quasi is the closest among the above ranged distance measurement data
Selecting distance measurement data corresponding to a certain distance measurement point
A camera is provided. According to a third aspect of the present invention, in addition to the above first aspect,
Distance measurement point in the center of the viewfinder screen
Is provided with a display unit for performing a display corresponding to
When the distance measurement data is detected and the line-of-sight detection means is activated,
A camera characterized by different display modes is provided.
It

[0009]

[0010]

In other words, in the first aspect of the present invention, the line-of-sight detecting means detects only whether or not the photographer is gazing at the central portion of the finder screen, and the selecting means detects the photographer by the line-of-sight detecting means. If it is determined that the user is gazing at the center of the screen, the distance measurement data at the center of the screen is selected, and if it is determined that the center of the screen is not gazing, the above multiple points are determined according to the predetermined criteria. One piece of distance measurement data is selected from the distance measurement data of. According to a second aspect of the present invention, in the first aspect, the predetermined determination criterion is
Of the distance measurement data of the above multiple points,
Ranging data corresponding to the ranging point is selected. A third aspect of the present invention is the same as the first aspect.
In the above viewfinder screen,
The distance measurement data detection
The display mode differs depending on the time of departure and the time of operation of the line-of-sight detection means
Is displayed.

[0011]

[0012]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a conceptual diagram of a camera of the present invention, which will be described. In the camera shown in FIG. 1A, the outputs of the central line-of-sight detection unit 3 and the multipoint AF unit 1 are connected to the input of the determination unit 10, and the output of the determination unit 10 is connected to the input of the focusing unit 2. It has been configured. In such a configuration,
The central line-of-sight detection unit 3 detects whether the photographer is looking at the central portion of the finder screen and outputs the information to the determination unit 10. The multipoint AF unit 1 is configured to measure a plurality of points on the screen, and the distance measurement information also determines the distance measurement information.
It is output to 0. The determination unit 10 determines the focusing distance based on these pieces of information, and controls the focusing unit 2 based on the result to focus. Therefore, according to this camera, it is possible to perform high-precision focusing overcoming the side effect of multi-AF by simply detecting the line-of-sight direction at one place.

Next, in the camera shown in FIG. 1 (b), the output of the line-of-sight detection unit 4 in which the right-eye line-of-sight detection unit 4a and the left line-of-sight detection unit 4b are integrated is connected to the input of the determination unit 10, The output of the determination unit 10 is connected to the inputs of the multipoint AF unit 1, the divided AE unit 5, and the focusing unit 2. In such a configuration, the line-of-sight detection unit 4 detects only whether the photographer is looking to the right or left in the screen. Then, when it is determined by the right-eye-gaze detecting unit 4a and the left-eye-gaze detecting unit 4b that the photographer is not looking right or left in the screen, the focus detection result at the center of the multipoint AF is prioritized.
Therefore, even in a situation where it is difficult to detect the line of sight depending on the conditions, the central distance measurement, which has a high probability of existence of the main subject, is prioritized, so that it is possible to take a photograph without failure. In addition, a division AE that allows distance measurement by dividing the screen according to the distance measurement points
Since the part 5 is provided, not only the focus but also the exposure can be adjusted to the main subject. With this configuration, since it is only necessary for the photographer to make a comparison determination when looking at the right side and when looking at the left side, there is an advantage that it is easy to detect the line-of-sight direction and failure does not occur easily.

Next, FIG. 2 shows the structure of a camera according to the first embodiment of the present invention, which will be described. The configuration shown in FIG. 1 is a further implementation of FIG. 1A, and shows the configurations of the central line-of-sight detection unit 3 and the multipoint AF unit 1 in detail.

In FIG. 2, reference numeral 7 is a photographer's eye, and reference numeral 7a is a blind spot. The blind spot 7a is a concentric portion of the optic nerve that does not produce vision even when the retina is exposed to light, and since it has no photoreceptor cells and is covered with a tissue having a relatively high reflectance, it has a high reflectance. It is known.
In the first embodiment, the light of the infrared light emitting diode (IRED) 11 is incident on the retina 7a through the half mirror 15, the reflected signal light is reflected by the half mirror 15, and the light is received by the light receiving element 18. To do. Polarizing filters 16 and 17 are arranged in this optical path so that specularly reflected light from the corneal surface of the eyeball 7 or the spectacle surface is not transmitted.

The driver 13 controls the light emission by passing a current through the IRED 11. On the other hand, the driver 14 controls the light emission by passing a current through the visible LED 12.
The visible light projected from the LED 12 is condensed by the lens 12a and enters the eyeball of the photographer. This LED 12
The light can also be emitted to display the central part of the camera finder screen. When the photographer gazes at the center of this screen,
The elements of the IRED 11 are arranged so that the light of the IRED 11 is diffused and reflected by the fundus of the eyeball of the photographer to become reflected signal light and is incident on the light receiving element 18. As the light receiving element 18, a semiconductor light position detecting element (PSD) having a function of detecting the incident position is used, and it is possible to determine at which position on the PSD the reflected signal light is incident. As a result, it is possible to continuously monitor where the line of sight of the photographer is facing within a certain range, and also it is possible to perform detection in consideration of individual differences between the eyes of the photographer.

Since the PSD 18 outputs two signal currents depending on the light incident position, the dedicated integrated circuit (I
C) 19 computes these two signal currents in an analog manner and converts them into a signal proportional to the light position.

Here, although the optical system of the finder is not shown in FIG. 2A, it is shown in FIG. 2B.
The reference numeral 29 in FIG. The photographer can observe the subject 30 through the finder optical system 29 and simultaneously receive the light of the IRED 11 into the fundus through the half mirror 28.

Reference numeral 1 in FIG. 2A shows a detailed configuration example of the detailed multipoint AF section 1. Reference numerals 25a, 25b,
25c is an infrared light emitting diode (IRE
D), and the light emission is sequentially controlled via the selective driver 20. The light from the IREDs 25a, 25b, 25c is projected through the light projecting lens 24, and the reflected signal light from the subject is incident on the PSD 22 through the light receiving lens 21.

Since the light projecting / receiving lenses 21 and 24 are arranged apart from each other by a predetermined base line length, the reflected light incident position changes in the base line length direction according to the object distance according to the principle of triangulation. The AFIC 23 is an integrated circuit for calculating the incident position of signal light from the two current signals of the PSD 22. These circuits are sequence-controlled and IC19, 23
The CPU 10, which is a one-chip microcomputer or the like, calculates the line-of-sight position and the subject distance from the output.

Hereinafter, referring to the flowchart of FIG.
The operation of the CPU 10 of the camera according to the first embodiment will be described. The CPU 10 detects the state of the 1st release switch 31 which opens when the release button of the camera is half pressed (step S1), and when the switch 31 is turned on,
Assuming that the photographer has started photographing, the sequence proceeds to step S2 and subsequent steps.

Subsequently, the distance measuring IREDs 25a, 25b,
25c are sequentially emitted to measure distances at 3 points on the screen (step S2), and the LE for display is displayed at the center of the finder screen.
D12 is turned on to show the center of the screen to the user (step S3). When the user gazes at the center of the screen, the IRED 11 for illuminating the fundus of the eye is arranged so that the illumination light can easily enter.
Signal Vc depending on the incident position of reflected light from the fundus from 19
Is input (step S4).

When it is determined that this Vc is within the predetermined range (step S5), the display LED 12 at the center of the screen is blinked to let the user recognize that the center of the screen is focused (step S6). Then, the state of the second release switch 32 which is opened by pressing the release button is detected (step S7), but when this is turned on,
The center distance measurement result lc is set as the focusing distance lp (step S8), and focusing is performed (step S9). After that, the CPU 10 controls the shutter mechanism to perform the exposure operation (step S10), turns off the display LED 12, and ends the sequence (step S11).

On the other hand, if it is branched to "No" in step S5, it is judged that the photographer is looking at a portion other than the center of the screen, and the second release switch is turned on (step S5).
12) Then, the closest result of the distance measurement results of the left and right sides and the center of the screen is set as the focusing distance lp, and the process proceeds to step S9 (step S14). The subsequent processing conforms to steps S9 to S11 described above.

As described above, in the camera according to the first embodiment, even in the scene as shown in FIG.
Even in a scene like (b), it is possible to focus on a person easily and quickly .

In the first embodiment, the line-of-sight detection operation can be performed only once by pressing the shutter release button, and even if the reliability thereof is low, in most cases, the closest selection of the multi-AF in step S14 is performed. Therefore, it is possible to guarantee the focusing with the same accuracy as the normal multi-AF. Further, in a situation where the release button is pushed down slowly and carefully, the reliability of the eye gaze detection operation increases.

Furthermore, in a scene with a cluttered subject as shown in FIG. 4B, if the user carefully and slowly releases the line of sight, the line of sight can be reliably detected, and the subject 30 in the center can be correctly focused. Can be combined. Since the display LED 12 blinks when the center is selected, there is no failure. Focus-lock photography is also possible by repeatedly detecting the line of sight and changing the composition while the display is blinking .

Also in the scene as shown in FIG. 4A, if the person 30 is first placed in the center of the screen, the release button is half-pressed to blink the display LED, and then the composition is returned to the position shown in FIG. 4A. The person 30 can be reliably focused. As described above, the present embodiment provides an AF camera which has a far simpler structure and is more effective than the AF camera based on the previously proposed visual axis detection result.

Further, in the first embodiment, the visual axis detection is performed after the three-point AF is performed in step S2 (step S4), but the AF may be performed after the visual axis detection is performed. Further, the determination ranges β1 and β2 of the signal Vc based on the output of the PSD 18 may be variable in consideration of individual differences of users.

Next, FIG. 5 shows the structure of a camera according to the second embodiment of the present invention based on FIG. In the second embodiment, two line-of-sight detection units indicated by reference numeral 3 in FIG. 2 are prepared so that it is possible to detect which of the left and right directions in which the user is looking.
Therefore, the description of the detection principle is omitted here, and the lens 12a and the polarizing plates 16 and 17 shown in FIG. 2A are not shown.

Further, the distance measuring device is assumed to be the one indicated by reference numeral 1 in FIG. 2A, and a photometric portion 5 for performing photometry at a plurality of points on the screen is added. The photometric unit 5 is composed of three-divided sensors 41a, 41b, 41c, a light receiving lens 42, and a sensor output processing circuit 43.
(B) The light from the portion 5a in the screen 8 is condensed and received via the lens 42, and the sensors 41a and 41c respectively receive the portions 5b and 5c in the screen, and the amount of light received by the circuit is The photometric result is input to the CPU 10 by 43.
Further, the CPU 10 can measure distances by time division of the positions 1a, 1b, 1c in the screen 8 by the AF unit 1. Further, the display LEDs for detecting the line of sight are 12a and 12b.
Is lit in the position.

Therefore, when the user gazes at these display LEDs, the light from the IRED 11a or 11b is reflected by the fundus and the reflected light enters the sensor 18a or 18b. If the user's eye is at the position of 70a, light is incident on the sensor 18a through the illustrated optical path, and if the eye is at the position of 70b, light is incident on the sensor 18b.

Therefore, if these sensor outputs are respectively amplified by the amplifiers 19a and 19b and compared by the comparator 40,
You can simply compare which direction you are looking at. Further, the IREDs 11a and 11b are made to be able to project light in pulses, and the sensor output at the time of projecting and at the time of non-projecting the comparator 40
So that you can compare with. IRED 11a, 11b
If there is no output difference between when the light is not projected and when the light is not projected, the user is not likely to look at it. Can be determined.

Hereinafter, with reference to the flowchart of FIG.
The operation of the CPU 10 of the camera according to the second embodiment having such a configuration will be described. When the operation starts, the CPU 10
The state of the t-release switch is determined (step S10
1) When the 1st release switch is turned on, the display LEDs 12a and 12b are turned on (step S10).
2), the outputs VR, VL and VR0, V of the amplifiers 19a, 19b when the IREDs 11a, 11b emit light and do not emit light
L0 is input to the CPU 10 (steps S103, S
104).

Next, when the output VR of the amplifier 19a when the right-eye gaze IRED 11a emits light is larger than the output VR0 of the amplifier 19a when it does not emit light (step S1).
05), the LED 1 for display indicates that the user is looking at the right side.
2a is blinked (step S117), and if the release switch is pushed, step S118 is "YES".
And the distance is measured by making the right distance measuring AFIRED (reference numeral 25a in FIG. 2A) emit light (step S12).
0), the photometric value B based on the output of the right side photometric sensor 41a
Is detected (step S121).

Then, focusing on the distance 1 (step S
110), exposure is performed based on the photometric value B (step S111), and finally the display LED is turned off to end the sequence (step S112). If step S105 is branched to “No”, the output results of the left eye gaze sensor 18b when the IRED 11b is projected and when it is not projected are compared, and the result VL when projected is the result VL0 when not projected. If it is obviously larger, the process branches to step S113 to perform left-side distance measurement and photometry (steps S115 and S116), and the sequence proceeds to step S110 and subsequent steps.

If step S106 is branched to "No", it is assumed that the left and right sides of the screen are not viewed and the distance measurement at the center of the screen is performed.
Photometry is performed (steps S108 and S109), and according to the result, focusing is performed (step S110) and an exposure operation is performed (step S111).

As described above, in the second embodiment,
Since it is only necessary to detect whether the user is looking at the left side or the right side, there is an advantage that the line-of-sight detection device can have a simpler structure and a lower cost than the conventional one. Further, also in the second embodiment, the subject 30 can be correctly focused and the exposure can be adjusted without fail in any of the scenes of FIGS. 4 (a) and 4 (b).

Further, in a situation where it is difficult to determine the line of sight, the design is such that 70% to 80% of the main subjects are present in the center of the screen (center priority), so photography with few failures can be enjoyed. . The remaining 20 to 30% of the photographs exist outside the center of the screen. At this time, the line-of-sight detection may be performed to select the distance measurement data or photometry data on the right or left side of the screen. At this time, it is difficult for the user to distinguish two adjacent points on the screen, and it is necessary for the detection device side to also require a complicated and expensive technique to detect a subtle change in the direction of the user's line of sight. Become. Therefore, in the second embodiment, the two line-of-sight detection points are separated as much as possible, and
The line-of-sight point is displayed like the positions 12a and 12b in (b).

In the prior art, the distance measuring point 1 is as possible.
The line-of-sight detection area 1 is at the point that matches a, 1b, and 1c.
2a, 12b, etc. were tried to be provided, but there is a high probability that the subject exists in the center of the screen, and the distance measuring points 1a, 1b,
If 1c is too far away, the subject will be out of focus if the subject enters the gap. On the other hand, even if the eyeballs try to see the same point, they vibrate called fixational tremor, so if the line-of-sight detection points are brought close to each other, the reliability at the time of detection becomes low.

On the other hand, in the second embodiment, as described above, the line-of-sight detection points are spaced as much as possible, and the distance measurement points are brought close to each other so as to respond to the AF failure, thereby improving the stability of operation and the ease of use. Is increasing. That is, the distance measuring point (3
The present invention makes it possible to design with high reliability, by taking measures against simple and inexpensive fixation tremor as compared with the case where the same number of visual axis detection points as the number of points).

In the above embodiments, the simplification of the visual axis detection technology and the performance guarantee when the judgment is difficult have been described. However, the performance guarantee when the visual axis detection and judgment is difficult is made by taking an amphibious camera as an example. The detailed third embodiment will be described.

First, FIG. 7 shows the arrangement of the optical system corresponding to FIG. In the third embodiment, IRED
The difference is that the light transmitted through the half mirror 28 of No. 11 is received by the light receiving element 51 via the prism 50. The prism 50 totally reflects the light of the above-mentioned IRED at the surface 50a and makes it enter the light receiving element 51. However, if water comes into contact with the position 1a, the total reflection condition will not be satisfied, and the light receiving element 51 will not be satisfied. The amount of received light will be reduced. That is,
The CPU (not shown) monitors the output of the light receiving element 51 to enable the underwater determination. As described above, the camera capable of underwater determination and line-of-sight detection is the third example, but it is considered that the user wears underwater glasses when taking an underwater photograph, and line-of-sight detection is impossible.

In the third embodiment, the line of sight is not detected at the time of underwater determination by the sequence shown in FIG. It is possible to prevent the user from mistakenly detecting the line-of-sight direction and performing distance measurement in an unexpected direction to take a failed photograph.

That is, when the ON of the first release switch is detected (step S200), the underwater detection result is judged from the output of the sensor 51 (step S201). If it is under water, the line of sight is not detected and the distance is measured (step S
210). This distance measurement may be the closest selection of the multipoint AF, but since it is underwater photography in which a relatively small subject is often photographed large, it may be performed in a form in which the multipoint distance measurement is prohibited as the central one-point distance measurement.

When it is determined that the subject is not underwater, line-of-sight determination is performed (step S202), and distance measurement is performed in consideration of the line-of-sight (step S203). Thus, step S2
When the 2nd release switch is turned on in 04, focusing is performed according to the distance measurement results in steps S203 and S210 (step S205), exposure is performed (step S206), and the sequence ends.

As described above, in the third embodiment,
Since it is common for photographers to wear underwater glasses underwater, we prohibited the line-of-sight detection and took measures to prevent false detection. In this way, the switching control can be performed so that the focusing is performed in consideration of the direction of the user's line of sight on land and the focusing is performed in the center, for example, in the water, so that accurate shooting without failure can be enjoyed depending on the situation.

Note that the signal light for illuminating the fundus of the above-described embodiment was emitted by the IRED 11 different from the display LED, assuming reflection from a blind spot having a high reflectance, but sufficient S /
If N is not obtained, it is not necessary to pay attention to blind spots or infrared rays, and the light of the LED for display may be used as the signal light for fundus irradiation. Further, in each of the above-described embodiments, the description is made on the premise of the multi-AF of the light projection type so-called active AF, but the multi-AF may be configured by the so-called passive AF based on the luminance distribution information of the subject.

As described in detail above, in the camera of the present invention, the simple and inexpensive visual axis detection device and the multi-point AF technology capable of measuring a plurality of points on the screen are effectively combined, and mutual problems are caused. Since they cancel each other out, it is possible to provide an autofocus camera that can focus on the main subject correctly in all scenes at low cost.

According to the above embodiment of the present invention, the following constitution can be obtained. (1) Distance measuring means capable of measuring a plurality of points including the center of the picture screen, central line-of-sight detecting means for detecting that the photographer is gazing at the center of the screen, and the central line-of-sight detecting means detecting the line of sight A camera comprising: a selection unit that selects the output of the distance measuring unit so that only the central distance measurement of the distance measuring unit is effective when the determination is made. (2) Peripheral line-of-sight determination means for determining that the photographer is detecting the peripheral portion within the photograph screen, distance measuring means for measuring the distance between the center and the periphery of the photograph screen, and the peripheral visual line determination means. When the line-of-sight cannot be determined, the camera further comprises a selecting means for selecting the output of the distance measuring means so that the distance measuring result at the center of the screen among the distance measuring means is valid. (3) Underwater determination means for determining whether the environment in which the camera is used is underwater or land, line-of-sight determination means for determining which direction the photographer is looking in the viewfinder screen, and a screen according to the output result of the line-of-sight determination means. In a camera having a distance measuring means for selecting distance measuring results of a plurality of points in the inside, when the underwater judging means judges that the water is underwater, the output result of the line of sight judging means is ignored and the output of the distance measuring means is ignored. And a selecting unit for selecting. (4) The photographer has a display unit for displaying a predetermined point on the finder screen for observing the subject, and a light projecting unit for projecting signal light from the vicinity of the display unit. A line-of-sight direction discriminating apparatus comprising a light-receiving unit provided so as to receive a reflected signal of the signal light from the fundus of the photographer when gazing at the unit. (5) In the line-of-sight direction determination device described in (4) above,
A line-of-sight direction discriminating apparatus comprising a light emitting element forming the display means, the light emitting element also serving as the signal light projecting means.

[0051]

According to the present invention, it is possible to provide a camera capable of taking a photograph in which a main subject is correctly focused in any scene with a simple structure.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a camera of the present invention.

FIG. 2 is a diagram showing a configuration of a camera according to a first embodiment of the present invention.

FIG. 3 is a flowchart showing an operation of the CPU 10 of the camera of the first embodiment.

FIG. 4A is a diagram showing a composition example in which a main subject is outside the center of the photographing screen, and FIG. 4B is a diagram showing a composition example in which a subject closer to the main subject is outside the center of the photographing screen.

FIG. 5 is a diagram showing a configuration of a camera according to a second embodiment of the present invention based on FIG. 1 (b) described above.

FIG. 6 is a flowchart showing an operation of the CPU 10 of the camera of the second embodiment.

FIG. 7 is a diagram showing an arrangement of optical systems of a camera according to a third example corresponding to FIG.

FIG. 8 is a flowchart showing the operation of the CPU according to the third embodiment.

[Explanation of symbols]

1 ... Multi-point AF section 2 ... Focusing section 3 ... Central line-of-sight detection unit 4 ... Line-of-sight detection unit 5: Split AF section 10 ... Judgment unit

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Claims (3)

(57) [Claims] 1. A camera capable of detecting distance measurement data of a plurality of points including the center of a photographing screen, and a line-of-sight detecting means for detecting only whether or not the photographer is gazing at the central portion of the finder screen. When the photographer determines that the photographer is gazing at the center of the screen, the distance measurement data at the center of the screen is selected and it is determined that the photographer is not gazing at the center of the screen. Means for selecting one distance measuring data from the distance measuring data of a plurality of points according to a predetermined judgment criterion;
A camera comprising: 2. The predetermined criterion is the plurality of points.
Of the distance measurement data of the
It is characterized by selecting the distance measurement data
The camera according to claim 1, wherein 3. Further, in the finder screen,
Display unit that displays the distance measurement points in the center of the screen
This display is equipped with the
The display mode is different when the detection means is activated.
The camera according to claim 1.