JP3393887B2 - Distance measuring device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring apparatus for selecting optimum distance measuring information from a plurality of distance measuring information by using information of a photographer's eyes. 2. Description of the Related Art Conventionally, in a camera having a multi-point distance measuring function, an erroneous distance measurement (hollow state) has occurred due to the presence or absence of distance at the time of photographing. In order to solve these problems, many means have been proposed for selecting the most suitable ranging information from the ranging information of a plurality of points. For example, JP-A-59-146028, JP-A-60-172008, and JP-A-60-2
No. 33610 discloses that an optimum location (closest, predetermined distance range) is selected from distance measurement information with emphasis on the center point. Further, Japanese Patent Application Laid-Open No. 1-27610
Japanese Patent Laid-Open Publication No. 6 (1999) discloses that various kinds of information are selected by fuzzy processing. [0004] Further, there has been proposed an image sensor that uses eye information for distance measurement. These are described, for example, in JP-A-60-1942.
No. 37 discloses a method of performing AF (autofocus) at a line-of-sight position, and Japanese Patent Application Laid-Open No. 63-40525 discloses a method of measuring a refractive index of an eye to measure a distance. [0005] By the way, when one piece of information is automatically selected from the distance measurement result of the multi-point distance measurement, camera information (focal length, photometric value, etc.), distance information, selection Although it is conceivable to use the priority order of the regions and the like, the degree of perfection of the completed photograph may be low because the intention of the photographer is not considered. Further, in order to more faithfully reflect the photographer's intention, a method has been proposed in which a distance measurement area is determined based on a line of sight and focus detection is performed in that area. However, since the position at which the photographer looks into the viewfinder and the distance from the viewfinder are not fixed, a large sensor (area sensor) or the like is required. As a result, an increase in cost and an increase in mounting size are inevitable. Was. A method has also been proposed in which the refractive index of the photographer's eyes is measured, and the focus position of the photographing lens is calculated based on the result. However, the amount of reflected light from the fundus is weak and the S is higher. / N signal cannot be obtained (the fundus has a phenomenon like birefringence reflection due to a thin transparent film structure). In addition, there is a problem that it is difficult to obtain the accuracy corresponding to the focal length and the ranging range of the photographing lens. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to complete a photograph which has been made without considering the photographer's intention even when one of a plurality of distance measurement information is selected. Even if the photographer's intention is reflected more faithfully without lowering the degree, the signal of high S / N can be obtained without increasing the cost and increasing the size of the mounting, and the focal length of the photographing lens, An object of the present invention is to provide a distance measuring device capable of obtaining an accuracy corresponding to a distance measuring range. That is, the present invention provides a multi-point distance measuring means capable of outputting distance information for a plurality of points on an object, and a focus detecting means for detecting a focus state of a user's eye. Without detecting the user's line of sight
The distance corresponding to the output of the focus detection
Distance information that is output had distance, characterized by comprising a selection means for al selection or a plurality of distance information detected by the plurality of points the distance measurement means. In the distance measuring apparatus according to the present invention, distance information is output for each of a plurality of points on the object by the plurality of points measuring means. The focus detection means detects the focus state of the user's eye. Then, the user's line of sight
Without detecting the direction, the output of the focus detection
Distance information that outputs the corresponding distance and the closest distance
Is a plurality of distances detected by the multi-point distance measuring means.
Selected from information . Embodiments of the present invention will be described below with reference to the drawings. First, before describing the embodiment, a method of detecting a focus state of an eye employed in the present invention will be described with reference to FIG. Generally, when a human clearly sees a subject,
The eye forms a light flux from the subject on the retina by changing the refractive index with the crystalline lens. FIG. 2A shows a state where the eye 1 is in focus. At this time, the object O
The light flux from _one point is refracted by the crystalline lens 2 and is imaged on the retina 3. FIGS. 2B and 2C show a state where the eye 1 is out of focus. Thus, when the eye 1 is looking at the point O ₁ (FIG. 3A), if the contrast pattern is projected from the point O ₁ , the contrast pattern is not blurred on the retina 3. . When the eye 1 emits a contrast pattern from the O ₂ point or the O ₃ point in the state shown in FIG. 2A, the contrast pattern is blurred on the retina 3. In other words, by projecting a contrast pattern from a position different from the optical path in a time division manner and detecting the state of the contrast pattern of the retina 3, the focus state of the eye 1 can be detected. FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. In FIG. 1, the distance measuring device includes a plurality of distance measuring devices 4 for detecting a distance, a focus detecting device 5 for detecting a focus state of the eye 1, a control of the focus detecting device 5, and a processing of an eye signal. , And a ranging point selecting device 6 for selecting an optimum value from the ranging signals of the plurality of ranging devices 4. The focus detection device 5 includes a pattern projection device 7 and an eye detection optical system 8 that projects a pattern by the pattern projection device 7 to detect a fundus state of the eye 1.
And a light receiving detector 9 for detecting a pattern image of the fundus of the eye 1
It is composed of In the distance measuring apparatus having such a configuration, an optimum value is selected based on a plurality of detected distance measurement information based on the focus state of eye 1. FIG. 3 is a block diagram showing a more detailed configuration of FIG. Note that active and passive multi-ranging methods generally used in cameras are known.
In the embodiment, an active distance measurement method will be described. The distance measuring device includes a multi-range measuring device 10,
A focus detection device for projecting light toward the eye from a position at an optically different distance; and a focus state of the eye is detected based on a signal detected by the focus detection device. It comprises a CPU 12 for detecting an optimum value from the distance measurement information detected by the device 10. The focus detecting device 11 includes a light projecting optical system a
13, pattern a14, IRED (infrared light emitting diode) a15, light projecting optical system b16, pattern b17, I
A light projecting block having the REDb 18, a light receiving optical system 19 for receiving and detecting fundus light of the eye 1, a sensor 20, and an A / D converter 21 for A / D converting an output signal of the sensor 20 and supplying the output signal to the CPU 12. And a light receiving block having The CPU 12 detects the focus state of the eye 1 based on the signal detected by the light receiving block, and detects an optimum value from the ranging information detected by the multi-ranging device 10. FIG. 4 shows a part of the configuration of a finder. A finder optical system 22 for guiding a subject light beam and a part of the finder optical system 22 are shared via a mirror 23 for infrared light. , A light receiving optical system 19 for detecting the state of the fundus of the eye 1 and a sensor 20. Further, the finder includes two sets of light projecting optical systems 13 and 16 having optically different distances, a pattern a14 and a pattern b17, a light projecting IREDa15 and a light projecting IR
It has EDb18. The light projecting system is configured to project light obliquely with respect to the finder optical axis. The sensor 20 is configured by a line-shaped sensor CCD, and the pattern a14 and the pattern b17 are configured to be easily detected by the line sensor. FIG. 5 is a diagram showing the position of the eyes and the appearance of the light-projecting pattern of the fundus when the patterns a14 and b17 are projected from the equivalent positions (A, B). . Here, the light projection pattern is shown for the case of one line. In this embodiment, the detection distance is divided into four parts,
Is set far from L1 (L0), II is set in the range from L2 to L1, III is set in the range from L4 to L3, and IV is set when it is closer to L4 (L5). The contrast threshold levels corresponding to II and III are K1 and K2. FIG. 5A shows an optical positional relationship between A and B. FIGS. 5B to 5E show the state of the pattern projected from the point A and the pattern projected from the point B on the fundus in a state where the focus position of the eye is at each point. It is a thing. FIG. 4B shows the case where the eye looks farther than point A, FIG. 4C shows the case where the eye looks near point A, and FIG. If present in
(E) is a case where the eye is looking at a short distance side from the point B. The focus state of the eye can be estimated based on the relationship between the projection position and the contrast. Active multi-AF is already known in cameras, but its configuration is simply shown in FIG. The description will be made based on a three-point measuring area method. In FIG. 6A, an infrared light source AF_IREDa for AF is transmitted through a light projecting optical system 24 of the camera.
b, c25, 26, and 27 are projected toward the subject in a time-division manner. Then, the reflected light from the subject is detected by the PSD 29 via the light receiving optical system 28. FIG. 6 (b)
Indicates the position of the focus area in the viewfinder. Focus areas a, b, and c correspond to the projection positions. Next, an operation of the camera to which the distance measuring apparatus is applied will be described with reference to a flowchart of FIG. When the AF sequence is started, first, initialization (set the focus area as a center)
Is performed (step S1). Then, first (1
st) Release “ON” is determined (step S)
2). Here, when the first release is “OFF”,
After the selected focus area is reset (step S
9), the sequence ends. In step S2, if the first release is "ON", the subroutine "A" for multi-ranging is performed.
F "is performed (step S3). Next, a subroutine" eye focus detection "is performed for determining which distance the eye is in focus (step S3).
4). Subsequently, a subroutine "selection of AF data" for selecting an optimum value from the multi-AF data in the state where the eye is in focus is performed (step S5). And 1
The first release is determined (step S6).
When the release is “OFF”, the process proceeds to step S9, and when the release is “ON”, the determination of the second (2nd) release is performed (step S7). If the second release is "OFF" at step S7, the process returns to step S6. On the other hand, "O
In the case of N ", after the photographing lens is driven based on the AF information (step S8), the present AF sequence ends.
FIG. 8 is a flowchart of a subroutine "AF" for detecting multi-AF data. When the subroutine "AF" is started and the infrared light source AF_IREDb 26 is projected (step S11), the position of the reflected light is detected by the PSD 29 (step S12). Then, the distance (Lb) of the focus area b is obtained from the position information of the PSD 29 (step S13). Next, focus areas a and c
, A similar sequence (corresponding AF_IRED
, And the distance is calculated by the PSD, and the distance (La) of the focus area a and the distance (Lc) of the focus area c are obtained (steps S14 to S19).
Thereafter, the present subroutine "AF" ends. Next, referring to the flowchart of “Eye Focus Detection” in FIG.
A subroutine for detecting the eye focus state will be described. When the subroutine "eye focus detection" is started, first, the sensor 20 is reset (step S21). Then, the IREDa 15 is projected (step S22), and sensor integration is performed (step S2).
3). Next, at the end of the integration, data is read (step S24), and A / D conversion of the read data is performed (step S25). When the contrast is calculated (total sum of absolute values of difference values between adjacent pixels: こ う A) (step S2)
6) The sensor is reset (step S27), and the infrared light source IREDb18 is emitted (step S28).
Next, sensor integration is performed (step S29), and when data is read at the end of integration (step S30), A / D conversion of the read data is performed (step S31). Then, when the contrast is calculated (） B) (step S32), the subroutine “eye focus detection” ends. FIG. 10 shows a flowchart of a subroutine "AF data selection" for selecting an optimum value from multi-AF data. The subroutine "selection of AF data" is started, and first, the contrast ΔA is compared with the reference value K1 (step S41). Here, ΣA <K1
If not, the flow shifts to step S42 to set Lmax to L.
1 is substituted for Lmin and L2 is substituted for Lmin. Step S41 above
If ΣA <K1, then the contrast ΣA and the contrast ΣB are compared (step S4).
3). If ΣA <ΣB is not satisfied in step S43, the flow shifts to step S44, where Lmax is set to L0.
L1 is substituted for min. On the other hand, if ΣA <ΣB,
Next, the contrast ΔB is compared with the reference value K2 (step S45). In this step S45,
If B <K2, the flow shifts to step S46, where Lmax
Is substituted for L3, and L4 is substituted for Lmin. In contrast, Σ
If B <K2, L4 is substituted for Lmax and L5 is substituted for Lmin (step S47). Thus, the above steps S42, S44,
After performing S46 and S47, it is determined whether or not the distance measurement data Lb in the multi-range measurement is within the range of Lmin and Lmax (step S48). Here, Lmin <
If Lb <Lmax, the process proceeds to step S50. On the other hand, when Lmin <Lb <Lmax is not satisfied, Lc is set to Lb.
Then, after MAX (the maximum value of the detection distance) is substituted for Lb (step S49), it is determined whether or not the distance measurement data La is within the range between Lmin and Lmax (step S50). In this step S50, Lmin <L
If a <Lmax, the process proceeds to step S52, and Lmin <
If La <Lmax is not satisfied, after MAX is substituted for La (step S51), the process proceeds to step S52. Then, in step S52, it is determined whether or not the distance measurement data Lc is within the range between Lmin and Lmax. Where Lmin
If <Lc <Lmax, the flow shifts to step S54, where Lmi
If n <Lc <Lmax, MAX is substituted for Lc (step S53). Thereafter, the minimum value is substituted for LD from the distance measurement data La, Lb, Lc (step S54). Next, comparison between LD and MAX is performed (step S5).
5). Here, if LD = MAX is not satisfied, this subroutine is terminated. On the other hand, when LD = MAX,
After the data of LC is substituted into LD (step S5
6), end this subroutine "AF data selection".
Although the embodiment of the present invention has been described above, the present invention is not limited to this, and it is needless to say that various improvements and modifications can be made. For example, if the focus detection area of the eye is 4
Although it is divided, it may be divided more finely. Further, the multi AF method may use a phase difference method or a contrast method. Further, the lens may be roughly initially driven while the eye is in focus. If the distance measurement data of a plurality of points exists in the focus detection area of the eye, a flowchart as shown in FIG. 11 may be performed. The flowchart of FIG. 11 is almost the same as that of FIG. 10, and the focus state of the eyes is set so that the data in the middle of the three data is selected when the closest area is selected. Only the following will be described. After MAX is substituted for Lc in step S53, a comparison is made between Lmin and L5 (step S57). Here, if Lmin = L5, the process proceeds to step S54, and if Lmin = L5, La, Lb,
The middle value of the data is assigned to LD from Lc (step S58). Next, comparison between LD and MAX is performed (step S59). Here, if LD = MAX, this subroutine is terminated as it is. If LD = MAX, the minimum value is substituted into the LD from the distance measurement data La, Lb, Lc (step S54), and then the LD and MAX are again processed. The comparison is performed (step S55), and after LD data is substituted into LD when LD = MAX (step S5).
6), end this subroutine "AF data selection".
As described above, the data to be selected may be changed for each detection area. The selection of the distance measurement data may be changed using the focal length information of the photographing lens. Further, the sensor for detecting the focus of the eye is not limited to a storage type (such as a CCD), but may be a non-storage type (such as a photodiode). The pattern light projection may be coaxial or the axis may be shifted, and the light projection pattern may be a point image. Regarding the focus state determination of the eye, instead of projecting the light projection pattern from a position having a different optical distance, as shown in FIG. Light from different angles. As the detection sensor, a position detection sensor 30, such as a PSD, which is installed so as to be focused near the fundus, is used. In the detection, instead of detecting the contrast state, the light is projected through the lens 31 and the infrared mirror 32.
D33 is emitted in a time-division manner, and is performed using both the position information of the corresponding PSD and the detection current of the PSD. That is, when the light projection IRED 33 is projected, it hits a position corresponding to the focus of the eye 1 lens, and the reflected light is focused on the PSD 30 via the eye 1 lens, the infrared mirror 32 and the mirror 31. The focus position of the eye is detected from the received light value of the reflected light. As described above, according to the present invention, when an optimum value is selected from a plurality of pieces of distance measurement information, the focus state of the user's eyes which is included in the user's intention is used. More accurate distance measurement information can be selected, and highly accurate focus detection can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention. FIGS. 2A and 2B are diagrams illustrating a method of detecting an in-focus state of an eye, wherein FIG. 2A illustrates a state in which the eye is in focus, and FIGS. 2B and 2C illustrate an in-focus state of the eye; It is a figure showing a state. FIG. 3 is a block diagram showing a more detailed configuration of FIG. 1; FIG. 4 is a diagram showing a part of a schematic configuration of a finder. 5A and 5B show a position where an eye is viewed and a state of a light projection pattern of a fundus when a pattern a and a pattern b are projected from equivalent positions (A and B), respectively. Are A, B
FIG. 4B is a diagram showing the optical positional relationship of FIG. 4B. FIG. 5B shows a case where the eye looks far from the point A, FIG. 5C shows a case where the eye looks near the point A, and FIG. If it exists between point B,
(E) is a diagram showing a state at the fundus of a pattern projected from points A and B when the eyes are looking at a short distance side from point B. FIG. 6A is a diagram illustrating a schematic configuration of active multi-AF, and FIG. 6B is a diagram illustrating a position of a focus area in a finder. FIG. 7 is a flowchart illustrating an operation of a camera to which the distance measuring device is applied. FIG. 8 is a flowchart of a subroutine “AF” for detecting multi-AF data. FIG. 9 is a flowchart of “eye focus detection” illustrating a subroutine for detecting an eye focus state; FIG. 10 is a flowchart of a subroutine “AF data selection” for selecting an optimum value from multi-AF data. FIG. 11 is another example of a flowchart of a subroutine “AF data selection” for selecting an optimum value from multi-AF data when distance measurement data of a plurality of points exists in the eye focus detection area. FIG. 12 is a diagram showing an example in which a light projection pattern is projected from a different angle with respect to the eye at substantially the same optical distance for the focus state determination of the eye. [Explanation of Signs] 1 eye, 2 lens, 3 retina, 4 distance measuring device,
5, 11: Focus detection device, 6: Distance measuring point selection device, 7:
Pattern projection device, 8: eye detection optical system, 9: light reception detection device, 10: multi-ranging device, 12: CPU, 13: light projection optical system a, 14: pattern a, 15: IRED (infrared light emitting diode) a, 16: light projecting optical system b, 17: pattern b, 18: IREDb, 19: light receiving optical system, 20: sensor, 21: A / D converter, 22: finder optical system,
23 ... Mirror.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-138434 (JP, A) JP-A-62-38134 (JP, A) JP-A-50-39128 (JP, A) JP-A 63-38128 40525 (JP, A) JP-A-2-5 (JP, A) JP-A-1-190177 (JP, A) JP-A-6-138378 (JP, A) JP-A-6-148504 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B ^7/ 28-7/34

Claims (1)

(57) [Claims] [Claim 1] Plural point distance measuring means capable of outputting distance information for each of a plurality of points of an object, focus detecting means for detecting a focus state of a user's eye, and use Focus detection without detecting the gaze direction of the
Output the closest distance and the distance corresponding to the output of the output means
Distance information are a distance measuring apparatus characterized by comprising a selection means for al selection or a plurality of distance information detected by the plurality of points the distance measurement means.