JPH10213738A - Range-finding device and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compact high-performance and high-function range-finding device by deciding a subject distance based on either output from a passive type focus detecting means or output from a 3rd photosensor. SOLUTION: This range-finding device is equipped with two light receiving lenses 1a and 1b and constitutes what is called an external light passive autofocusing module 11 where received luminance distribution information of the subject 6 is received by sensor arrays 2a and 2b for passive autofocusing so as to obtain the distance to the subject 6 based on the deviation. The 3rd photosensor 2c set at the middle position of a semiconductor chip 2 equipped with two sensor arrays 2a and 2b is used to perform what is called active autofocusing where the subject distance is obtained by receiving the component reflected from the subject 6 out of signal light projected from a camera side. Thus, the subject distance is decided based on either output from the passive type focus detection means or output from the 3rd photosensor 3c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device and a camera, and more particularly to a distance measuring device and a camera for measuring a subject distance using luminance distribution information of the subject.

[0002]

2. Description of the Related Art In recent years, the miniaturization of batteries and films and the improvement of photographic lenses have spurred the miniaturization of cameras, and products with higher performance but better design and better portability have been introduced to the market. is there. Under such a tendency, there is a demand for miniaturization of functional blocks and units such as autofocus, automatic exposure and remote control. Regarding the autofocus, an optical system, a sensor, and a processing circuit, which are modularized and miniaturized, are already known.

[0003] In addition, by adding other functions to these,
There are also proposals to add additional features within the same volume to increase added value. For example, Japanese Patent Application Laid-Open No. 3-46507
Japanese Unexamined Patent Publication No. 8-278125 discloses a technical means in which an auxiliary light and a sensor are compactly combined by devising an optical system. There is disclosed a technical means for increasing the added value by making the distance possible.

[0004]

However, the technical means disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 3-46507 has a complicated optical system, is difficult to design and assemble, and is susceptible to changes due to temperature and humidity. As a result, there is a problem that the performance is deteriorated. Further, Japanese Patent Application Laid-Open No.
The technical means disclosed in Japanese Patent No. 278125 is an extension technique of passive auto focus, and it is difficult to take measures against its weak points (weak in low contrast and low brightness) and to provide a function other than auto focus. I couldn't do it either.

The present invention has been made in view of the above problems, and has as its object to provide a small, high-performance, high-performance distance measuring apparatus and camera.

[0006]

In order to achieve the above object, a first distance measuring apparatus according to the present invention receives two light patterns from a subject received from two optical paths with parallax by two sensor arrays. A passive focus detection unit that determines a subject distance based on a shift amount of the two light patterns based on the parallax; a projection unit that projects ranging light toward the subject; A third optical sensor disposed between the third optical sensor for receiving the light for distance measurement, and determining means for determining an object distance based on either the output of the passive focus detecting means or the output of the third optical sensor And

In order to achieve the above object, a second aspect of the present invention
The distance measuring device according to claim 1, wherein the third distance measuring device is the same as the first distance measuring device.
The optical sensor of (1) also serves as a light receiving element for a remote control transmitter or a photometric element for exposure control.

In order to achieve the above object, a camera according to the present invention receives two light patterns from a subject, which are received from two optical paths with parallax, by two sensor arrays via two light receiving lenses. Passive focus detection means for determining a subject distance from a shift amount of the two light patterns based on the first and second light patterns; a third light sensor disposed between the two sensor arrays; and a third light sensor disposed on the third light sensor A third light receiving lens having a wider light receiving range than the two light receiving lenses, and performs spot light metering based on the output of the sensor array; and performs the spot light metering based on the output of the third light sensor. It is characterized in that photometry in a wider range is performed.

The first distance measuring device is a passive focus detecting means, which receives two light patterns from a subject which are received from two optical paths with parallax by two sensor arrays, and receives the two light patterns based on the parallax. The subject distance is determined from the shift amount of the light pattern. Further, light for distance measurement is projected from the light projecting means toward the subject, and the light for distance measurement is received by a third optical sensor. Then, the subject distance is determined based on either the output of the passive focus detection means or the output of the third optical sensor.

The second distance measuring device is the same as the first distance measuring device, wherein the third optical sensor is also used as a light receiving element for a remote control transmitter or a light measuring element for exposure control.

The camera performs spot photometry based on the output of the sensor array, and performs photometry over a wider range than the spot photometry based on the output of the third optical sensor.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing a schematic configuration of a distance measuring apparatus according to a first embodiment of the present invention.

Here, prior to a detailed description of this embodiment, a schematic configuration and operation of the distance measuring device will be described with reference to FIG.

This distance measuring device has two light receiving lenses 1a,
1b, the passive autofocus sensor arrays 2a and 2b respectively receive the luminance distribution information of the subject 6 received through these light receiving lenses, and obtain the subject distance to the subject 6 based on the amount of deviation. It constitutes an external light passive autofocus module. Further, a third sensor 2c is provided at an intermediate position of the semiconductor chip 2 having the two sensor arrays 2a and 2b, and the signal light projected from the camera side is reflected from the subject by using the third sensor 2c. The so-called active auto-focus for obtaining the object distance is performed by receiving the component thus obtained, thereby eliminating the weak point of the passive auto-focus.

As an application of this embodiment, the third sensor 2c is used as a sensor for receiving a remote control signal of a camera (see the second embodiment), or an AE.
It is possible to provide a more compact camera by using such a sensor as a receiving sensor (see the fourth embodiment) to reduce the need for these sensors conventionally.

Furthermore, not only the configuration of the sensor chip,
Various measures such as limiting the wavelength of light incident on the third sensor 2c are taken.

Referring to FIGS. 2 and 3 in addition to FIG. 1, the method of calculating the relative position difference between the light patterns of the above-described passive distance measuring apparatus will be described in further detail.

The position difference B between the two light receiving lenses 1a and 1b
Due to the (base line length), the relative position difference x of the light distribution incident on the sensor arrays 2a and 2b changes depending on the subject distance L. Assuming that the focal length of each of the light receiving lenses 1a and 1b is f, the subject distance L is obtained as L = B × f / x.

Each of the sensor arrays 2a and 2b outputs a current signal in accordance with the amount of incident light,
If the signal is converted into a digital signal by the D converter 4, the above x can be detected by a correlation operation by the image shift amount operation circuit 5. The distance L is obtained by inputting the result to an arithmetic control means (CPU) 10 comprising a one-chip microcomputer or the like and calculating the above equation. This is the basic principle of the passive triangulation and is a general configuration.

The shift amount calculating function generally includes two processes as described later.
0 may be incorporated. When a camera is focused by such a technique, the CPU 10 controls the operation of the camera, and the camera focusing lens for photographing of the camera is controlled via an actuator such as a motor. Can be provided.

First, in the image shift amount calculation, a step of checking how much the image is shifted in units of a sensor pitch (correlation calculation).
Need. Then, an interpolation operation step for calculating the shift amount more precisely with a finer resolution is required.

The sensor arrays 2a and 2b are formed on the same semiconductor chip 2 on the left and right sides, respectively. The sensor array 2a is formed on the right side, and the sensor array 2b is formed on the left side. It is configured. In the present embodiment, the sensor array 2a is constituted by sensors R1 to R6 as right sensors, while the sensor array 2b is constituted by sensors L1 to L6 as left sensors.

Now, when light is incident on the sensor arrays 2a and 2b in a pattern indicated by reference numerals 3a and 3b in FIG. 1, respectively, each of the sensors R1 to R6 or L1 to L6 constituting the sensor arrays 2a and 2b. The magnitude of each output has a distribution as shown in FIGS. 2 (a) and 2 (b).

In FIG. 2, R and L indicate a right sensor (sensor array 2a) and a left sensor (sensor array 2b), respectively, and the suffixes 1 to 6 attached thereto are, for example, based on the optical axis of the light receiving lens. It is assumed that the absolute position of the sensor is indicated. At this time, the left sensor (sensor array 2
The outputs L1 to L6 of b) are the outputs R1 to R6 of the right sensor.
Since the relative position difference x of the light distribution is “0”, the subject distance L is infinity.

On the other hand, if the subject 6 is at a finite distance, the left sensor (sensor array 2b)
At the position shifted by the number S of sensors determined from the sensor pitch sp and the sensor pitch sp, similar outputs of R1 to R6 are obtained on the left sensor (see FIG. 2B).

The value S can be obtained by subtracting the output of the corresponding left sensor from the output of the right sensor and adding the absolute value of each sensor to the result "FF". This "FF" is obtained by first subtracting Li from each of the predetermined corresponding sensors Ri, taking an absolute value, changing the value i within a certain width, and adding them. That is, FF (i) = Σ | R (i) −L (i) | Then, one sensor of Ri or Li is shifted by 1 and
Taking the difference in the same way as for the adjacent sensor that took the difference earlier can be expressed by the following equation.

FF (i + 1) = Σ | R (i + 1) −L (i) | In this manner, the FF is sequentially changed while changing the shift amount SIFT.
Is a graph as shown in FIG. 3,
Since the SIFT amount at which the FF, which is the sum of the difference between R and L, has the minimum value (Fmin) is considered to be the best, the SIFT amount at this time is obtained as S. Taking this S into consideration, the output distribution of both sensor arrays 2a and 2b is illustrated, as shown in FIG. 2B, similar to the right sensors with subscripts corresponding to the left sensors shifted by S from the left sensors. Is obtained.

Next, the interpolation operation will be described.

The displacement of the images on the two sensor arrays 2a and 2b is not exactly shifted by the pitch of the sensor. Therefore, accurate distance measurement is required unless the displacement of the image is detected with a precision smaller than the pitch. Can not. When detecting the image shift amount with higher accuracy, a process called interpolation calculation is used. Hereinafter, the interpolation calculation process will be described with reference to FIG.

In FIG. 4, R and L respectively denote a part of the sensor arrays 2a and 2b of FIG. 1. It is shown. Therefore, L0 to L in FIG.
4 should be described exactly from Ls to Ls + 4, but since it is complicated, S is omitted here.

Now, the left sensor array (sensor array 2)
In b), it is assumed that light shifted by x with respect to the right sensor array is still incident after the shift by S.
At this time, for example, the light incident on the right sensors R0 and R1 is mixed and incident on the L1 sensor of the left sensor, and similarly the light shifted by x with respect to the right sensor is sequentially incident on each left sensor. Thus, it is understood that the output of each left sensor is expressed as shown in the following (Equation 1).

(Equation 1) L1 = (1−x) · R1 + xR0 L2 = (1−x) · R2 + xR1 L3 = (1−x) · R3 + xR2 From the above-mentioned Fmin and Fmin, the above shift amount is added in the plus and minus directions. Shifted FF values F-1, F + 1
Is expressed using the outputs of Rn and Ln as shown in the following (Equation 2).

(Equation 2) Fmin = Σ | Rn-Ln | F-1 = Σ | Rn-1-Ln | F + 1 = Σ | Rn + 1-Ln | ) Expands to
(Expression 3) is obtained.

(Equation 3) Fmin = │R1-L1│ + │R2-L2│ + │R3-L3│ = │R1- (1-x) R1-xR0│ + │R2- (1-x) R2- xR1│ + │R3- (1-x) R3-xR2│ = │R1-R1 + xR1-xR0│ + │R2-R2 + xR2-xR1│ + │R3-R3 + xR3-xR2│ = x│R1- R0│ + x│R2-R1│ + x│R3-R2│ = x ｛│R1-R0│ + │R2-R1│ + │R3-R2│｝ F-1 = │R0-L1│ + │R1- L2│ + │R2-L3│ = │R0- (1-x) R1-xR0│ + │R1- (1-x) R2-xR1│ + │R2- (1-x) R3-xR2│ = │R0 -R1 + xR1-xR0│ + │R1-R2 + xR2-xR1│ + │R2-R3 + xR3-xR2│ = │ (1-x) (R0-R1) │ + │ (1-x) (R1- R2) │ + │ (1-x) (R2-R3) │ = (1-x) ｛│R0-R1│ + │R1-R2│ + │R2-R3│｝ F + 1 = │R2-L1│ + │R3-L2│ + │R4-L3│ = │R2- (1-x) R1-xR0│ + │R3- (1-x) R2-xR1│ + │R4- (1-x) R3-xR2 │ = │R2-R1 + xR1-xR0│ + │R3-R2 + xR2-xR1│ + │R4-R3 + xR3-xR2│ = x ｛│R1-R0│ + │R2-R1│ + │R3-R2 │｝ + │R2-R1│ + │R3-R2│ + │R4-R3│ ≒ (1 + x) ｛│R0-R1│ + │R1-R2│ + │R2-R3│｝ where │R1-R0 │ ≒ │R4-R3│ ｛│R0-R1│ + │R1-R2│ + │
If R2−R3 |｝ is expressed as (ΣΔR), the deviation amount x is obtained without depending on (ΣΔR) as in the following (Equation 4).

(Equation 4) When (ΣΔR) = ｛│R0-R1│ + │R1-R2│ + │R2-R3│｝, Fmin = (ΣΔR) x F-1 = (-1ΔR) (1-x ) F + 1 = (ΣΔR) (1 + x) ∴ ∴ (F-1)-(Fmin)｝ / ｛(F + 1)-(Fmin)｝ = ｛(ΣΔR) (1-x)-(ΣΔR) x ｝ / ｛(ΣΔR) (1 + x) − (ΣΔR) x｝ = ｛(ΣΔR) (1-2x)｝ / (ΣΔR) = 1-2x This is the interpolation operation.

In the present embodiment, these calculations are performed in the calculation circuit 5 shown in FIG. 1. However, calculation control means (CPU) 1 such as a one-chip microcomputer or the like is used.
0 may be performed according to a predetermined program.

Next, a specific configuration of the distance measuring apparatus according to the first embodiment will be described.

The distance measuring apparatus according to the first embodiment is provided inside a passive autofocus module 11 shown in FIG. As shown in the figure, in the distance measuring apparatus of the first embodiment, a third light receiving lens 1c is provided between two light receiving lenses 1a and 1b, and corresponds to the third light receiving lens 1c. And two sensor arrays 2 described above
a, a second photoelectric conversion element (third sensor) 2
c is provided. This third photoelectric conversion element 2c
Like the two sensor arrays 2a and 2b, they are formed on the same semiconductor chip 2. Further, as described above, the sensor arrays 2a and 2b are formed on the same semiconductor chip 2 on the left and right sides, respectively, with the sensor array 2a on the right side and the sensor array 2b on the left side. It is composed in groups.

As described above, in order to perform triangulation, a predetermined base line length B is set between the two light receiving lenses 1a and 1b.
is necessary. Accordingly, two sensor arrays 2a,
Although a predetermined interval is required between 2b, a dead space occurs between the two sensor arrays. The distance measuring apparatus of the present embodiment focuses on this point, and the third sensor 2c is arranged and configured using this space.

The output terminals of the two sensor arrays 2a and 2b are connected to an A / D converter 4. After the A / D converter 4 performs A / D conversion, a predetermined operation is performed by an operation circuit 5. Is applied. The output of the arithmetic circuit 5 is C
The data is input to the PU 10.

Further, the distance measuring apparatus of the first embodiment is
An infrared light emitting diode (IRED) 8a for turning on / off the light emission according to the control of the CPU 10 and the current supply of the IRED driver 8 is provided, and the light of the IRED 8a is projected onto the subject 6 by the light projecting lens 9. It has become. Further, the projected infrared signal light is reflected by the subject 6, and is incident on the third sensor 2c via the light receiving lens 1c.

On the other hand, in front of the third sensor 2c, an infrared transmitting visible light cut filter 1d is provided.
It prevents light other than the signal light from being incident on the third sensor 2c, and serves to improve the S / N ratio.

The method of measuring the distance by the reflected light of the light projected from the camera in this way is called generalized active autofocus.

Next, with reference to FIG. 5, the principle of this active type autofocus will be described.

The light projected from the IRED 8a is condensed and projected by the light projecting lens 9, reflected by the object 6, and passes through the light receiving lens separated by the base line length S to the third sensor 2a.
c. Similar to the principle of the passive autofocus shown in FIG. 1, the base line length S, the focal length fj of the light receiving lens, the object distance, and the object distance L are different from the incident position X of the reflected signal light by the principle of triangulation. The following relationship is established.

X = S · fj / L Therefore, the object distance L can be obtained by obtaining the incident position X. In general, a technique for detecting the incident position X using a semiconductor position detecting position (PSD) that outputs a current signal according to the incident signal position and the light amount, or a two-division photodiode is conventionally known. . Further, since the light quantity of the incident signal decreases as the distance increases, a distance measuring method using a simple light quantity such as a long distance if the photoelectric flow rate is small and a short distance if the photoelectric flow rate is large is also known.

Therefore, in the distance measuring apparatus of the first embodiment, the IRED 8a is projected when the passive autofocus cannot perform the correlation calculation because the subject has no contrast or the like, and the signal light is transmitted to the third sensor. The light is received at 2c, and the subject distance is determined according to the incident position or the light amount.

Here, the arrangement of the third sensor 2c used as an active autofocus sensor will be described with reference to FIG.

In view of the principle of triangulation, the position of the third sensor 2c needs to be arranged at a position farther from the light projection (IRED 8a, light projection lens 9) side. Therefore, in the distance measuring apparatus of the present embodiment, as shown in the figure, the distance between the sensors is set to the distance W1: the sensor array 2a closer to the light projecting side.
W2: distance between the third sensor 2c and the third sensor 2c at a position where the distance between the sensor array 2b farther from the light emitting side and the third sensor 2c satisfies W1> W2.
Has been arranged.

Returning to FIG. 1, the output terminal of the third sensor 2c is connected to the CPU 10 via the AF circuit 7. The output of the third sensor 2c is such that the stationary light is removed by the AF circuit 7 and only the signal light is separated and input to the CPU 10. That is, the third sensor 2
Normal light other than signal light, such as sunlight or electric light, is also normally incident on c, and the AF circuit 7 removes the photocurrent due to the light with a filter or the like and outputs the current to the CPU 10. .

When the third sensor 2c is constituted by a PSD, the sensor 2c outputs two photocurrent signals. Therefore, if only the signal components are taken out of these and the ratio is taken, the light incident position is obtained. A signal according to X can be calculated.

When applied to a simple reflected light amount detection type autofocus, the sensor 2c may be constituted by a simple photodiode.
The F circuit 7 only needs to have a function of removing the current due to the steady light and determining the signal light amount.

As described above, by employing the distance measuring apparatus of the first embodiment, a small camera that can handle any object can be provided.

Next, a second embodiment of the present invention will be described.

FIG. 6 is an explanatory diagram showing a schematic configuration of a camera system including a distance measuring apparatus according to a second embodiment of the present invention. In the figure, the configuration of a camera provided with the distance measuring apparatus of the second embodiment is shown by blocks on the right side in the figure, and the subject is shown on the left side. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this camera system, the subject indicated by reference numeral 6 in the figure can operate the remote control transmitter 18 for the camera to perform operations such as remote shooting. That is, when the third sensor 2c detects an optical signal from the remote control transmitter 18 activated by the operation of the subject 6, the CPU that controls the entire camera and performs the same function as the CPU 10 described above. The photographing lens 17 is focused, and the shutter 15 is controlled to perform photographing.

That is, in the distance measuring apparatus of the second embodiment, the third sensor 2c serves as a light receiving sensor of the remote control transmitter 18. Note that the third sensor 2c is also used as a sensor for active autofocus in the second embodiment as in the first embodiment. Switching between the active autofocus sensor and the remote control signal receiving sensor is performed by analog switches 13a and 13b.

That is, when the analog switch 13a is turned on, the remote control circuit 12 is connected between the third sensor 2c and the CPU 10 so as to be inserted. The third sensor 2c is a remote control signal receiving sensor. It works. The remote control circuit 12 uses a filter to determine only the frequency of the transmission pattern of the remote control transmitter and does not mix it with other light.

On the other hand, when the switch 13b is turned on, the A
The F circuit 7 is connected so as to be inserted in the same manner, and functions as a sensor for active autofocus similarly to the first embodiment. The analog switches 13a and 13b are turned on and off by the CPU 10.

The operation of the second embodiment having such a configuration will be described with reference to the flowchart shown in FIG.

First, it is detected whether or not the camera is in a remote control mode (remote control mode) (step S1). If the camera is in the remote control mode, the analog switch 13a is turned on and the switch 13b is turned off. The third sensor 2c functions as a remote control signal receiving sensor. Thereafter, when the input of the remote control signal (remote control signal) is detected (step S4), the process proceeds to step S5, where the analog switch 13a is turned off and the analog switch 13 is turned off.
b is turned on to switch the third sensor 2c to a sensor for autofocus. At this time, the third sensor 2c is connected to the AF circuit 7 in the same manner as in the first embodiment, and the subject distance is obtained by operations such as removal of stationary light for active autofocus and detection of a light incident position. It has become.

Thereafter, active autofocus (step S6) by projecting the IRED 8a and passive autofocus by the two sensor arrays 2a and 2b (step S7) are performed, and the respective results are LA and LP.
Next, of these, the one indicating the short distance is set as the focusing distance, and the photographing lens 17 is focused in accordance with this focusing distance. Thereafter, the shutter 15 is controlled to complete photographing.

In step S1, if the mode is not the remote control mode, the camera executes steps S5 and subsequent steps in accordance with the operation of the release switch 14, and performs photographing in the same manner as when remote control is detected.

The reason why the short distance is selected as the focusing distance in step S8 is to prevent out-of-focus in a scene as shown in FIG.

That is, in a backlit scene where the background 6 'is brighter than the main subject 6, the background subject has a stronger contrast between light and dark, so that the background is in focus or the luminance distribution between the person and the background is high. In some cases, the result of ranging from a person farther than that of a person (mixed distance) may be obtained. In the active autofocus, such a problem does not occur if the projected signal light is correctly applied to the subject, and it is effective to use a result at a short distance to prevent such a problem.

As described above, according to the distance measuring apparatus of the second embodiment, a sensor for receiving a remote control signal, which is conventionally required separately, is built in the distance measuring module 11, so that a smaller remote controller is provided. A camera with a control function can be provided.

In addition to passive auto focus,
In consideration of the result of the active autofocus, it is possible to provide a highly reliable autofocus function which is more reliable and has no problem of backlighting or mixed perspective.

Next, a third embodiment of the present invention will be described.

FIG. 9 is an explanatory diagram showing a schematic configuration of a distance measuring apparatus according to a third embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The first and second embodiments are characterized in that a third light receiving lens 1c and a visible light cut filter 1d are provided between the light receiving lenses 1a and 1b (see FIGS. 1 and 6). However, in the third embodiment, the first,
Unlike the second embodiment, only two light receiving lenses are provided (1a, 1b) as in the conventional passive autofocus module, and one light receiving lens 1b is also used for active autofocus. In addition, since the configuration inside the module 11 is the same as that of the first embodiment,
Detailed description here is omitted.

In addition, in order to remove the light other than the signal light and improve the S / N ratio, a visible light cut filter seal which serves the same function as the visible light cut filter 1d is provided in front of the third sensor 2c. Alternatively, the passive sensor may be provided with infrared sensitivity so that passive distance measurement is performed only with infrared light, and visible light cut processing may be performed by mixing a dye into the light receiving lenses 1a and 1b. Good.

When the signal of the active signal light is sufficiently large at a short distance, the S / N ratio is sufficient and the distance can be measured without these visible cut processes. No visible light cut is required.

In the third embodiment, the IRED
Are prepared, and these are sequentially emitted, and the distance is measured by determining which IRED emits the most reflected signal light. For example, the distance measuring device of the present embodiment includes two IREDs 8a and 8b as shown in FIG. In addition,
These IREDs are located close to the light receiving lens.
a, and the IRED 8b is provided at a remote position.

The two IREDs 8a and 8b
Is emitted, when there is a short-distance subject as is apparent from the optical path shown in the figure (indicated by reference numeral 6b in the figure), the third
Much light from the IRED 8b is incident on the sensor 2c.
Conversely, when there is a subject at a long distance (indicated by 6a), I
The light from the RED 8a is more strongly incident on the third sensor 2c. Therefore, these IREDs 8a, 8
The subject distance is obtained by comparing the amount of light received when b emits light.

In the third embodiment, the output terminal of the third sensor 2c is connected to the CPU 10 via the stationary light (DC light) removing circuit 7a and the intensity determining circuit 7b. Then, of the output current of the third sensor 2c, the stationary light component is removed by the stationary light removal circuit 7a, and only the reflected signal light amount is determined by the intensity determination circuit 7b. Has become.

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

First, the IRED 8b disposed farther from the light receiving lens is projected (step S11). At this time, a corresponding photocurrent is output from the third sensor 2c. The stationary light component of the photocurrent is a stationary light removal circuit 7a.
And a signal depending on the photocurrent ipb is input to the CPU 10.

Next, in the same manner as described above, the IRED 8a disposed near the light receiving lens is projected (step S12), and the steady light component of the photoelectric current output from the third sensor 2c is changed to the steady light removing circuit 7a. And a signal depending on the photocurrent ipa is input to the CPU 10.

Next, the CPU 10 compares the photocurrents ipa and ipb (step S13). If the photocurrent ipb is larger, it is determined that the subject is a short distance as described above, and the focusing distance is set to a predetermined distance. , For example, 1 m (step S16). Step S13
In the above, when the photocurrent ipa is larger, it is considered that the distance is farther, and the ipa is compared with a predetermined level ipo (step S14). When it is smaller than ipo, the reflected signal light amount is small, Therefore, a predetermined distance, for example, 3 m is set as the focusing distance (step S1).
5). On the other hand, when the photocurrent ipa is larger than ipo, focusing is performed on the intermediate 2 m (Step S).
17).

As described above, when the distance measuring apparatus according to the third embodiment is used, only the semiconductor chip 2 is improved by using the pair of light receiving lenses of the conventional passive autofocus module without any modification. It is possible to provide a camera with an autofocus function that can correctly measure a distance to a scene that is difficult with conventional passive autofocus.

For example, even in a dark scene where there is no contrast in the luminance distribution and no correlation can be obtained, it is possible to perform focusing by active autofocus.

Next, a fourth embodiment of the present invention will be described.

FIG. 11 is an explanatory diagram showing the configuration of a camera system including a distance measuring apparatus according to a fourth embodiment of the present invention. In the figure, the configuration of the camera provided with the distance measuring apparatus of the fourth embodiment is shown by blocks on the right side of the figure, and the subject is shown on the left side. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The distance measuring apparatus according to the fourth embodiment is the same as the two sensor arrays 2 according to the first and second embodiments.
The third sensor 2c provided between a and 2b is also used for photometry. Further, instead of the IRED used in the first embodiment and the like, a strobe light for assisting exposure of a camera is used as a projection light source. In FIG. 11, the configuration inside the module 11 is the same as that of the first and second embodiments, so that the detailed description is omitted here.

Hereinafter, the output terminal of the third sensor 2c and C
The stationary light removal circuit 7c newly provided between the PU 10 and the PU 10
The configuration of the A / D converter 7d will be described along the signal flow.

First, the stationary light removing circuit 7c will be described. The output photocurrent of the third sensor 2c is
3 and further amplified by the amplifying transistor 24. The base current of the transistor 24 is monitored by an amplifier 22 that detects the emitter potential of the transistor 24. That is, when the photocurrent of the third sensor 2c increases, the emitter potential of the transistor 24 decreases. By detecting this potential at the negative input terminal of the amplifier 22, the current input to the base of the transistor 24 can be monitored. .

On the other hand, a reference voltage Vref is applied to the + input terminal of the amplifier 22. When the emitter potential of the transistor 24 falls below this reference level, that is, the photocurrent of the third sensor 2c becomes lower than a predetermined value. As the number increases,
The amplifier 22 raises the base potential of the transistor 27, and the photocurrent of the third sensor 2c flows to the ground according to the operation of the transistor 27. Therefore, by appropriately setting the level of the reference voltage Vref, the current flowing through the transistor 24 can be suppressed to a predetermined level or less.

In this state, when the xenon tube 21 emits light by the strobe circuit 20 arranged in the camera equipped with the distance measuring device and the CPU 10 stops the operation of the amplifier 22, the photocurrent before the light emission becomes the base of the transistor 27. Since the potential is fixed by the capacitor 28,
Only the photoelectric flow reflected from the subject flows into the base of the transistor 24, and the current flows into the integrating capacitor 26 by the current mirror circuit 25 formed by the PNP transistor pair. As a result, the integrated voltage of the integrating capacitor 26 becomes a signal that depends only on the reflected signal light amount, not on the steady light amount.

The output of the stationary light elimination circuit 7c, which outputs a signal depending only on the amount of reflected signal, is A / A
The signal is converted into a digital signal by the D converter 7d and input to the CPU 10. Then, the CPU 10 determines the amount of the reflected signal based on the signal.

In the fourth embodiment, the AE circuit 19 is connected to the output terminal of the amplifier 22.
As described above, in the distance measuring apparatus of the present embodiment, the third sensor 2c is also used as a photometric element for exposure control. However, as described above, the emitter potential of the transistor 27 is different from that of the signal light. Since it changes depending on the amount of incident light,
This level is detected by the AE circuit 19, and a signal corresponding to the level is output to the CPU 10.
Thus, the CPU 10 measures (light-meters) the amount of light incident on the third sensor 2c.

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

First, as described above, the transistor 2
7 is detected by the AE circuit 19, and the amount of light incident on the third sensor 2c is measured by the CPU 10 (step S18). Next, passive distance measurement is performed by the AF module 11 (step S19), and the result is set to L. Thereafter, a trigger voltage is applied to the xenon tube 21 via the flash circuit 20 to emit light, and the object 6
Is obtained (step S20).

As a result of the passive distance measurement in step S19, it is determined whether or not the subject has a contrast (step S21), and there is no contrast (low contrast).
Is determined in step S25.
At 20, the reflected signal light quantity ip is compared with the reference value ipo for determination. In this step S25, the reflected signal light amount i
If p is smaller than the reference value ipo, it is determined that the distance is long (step S27). If p is larger, the focus is adjusted to the normal focal length, for example, 2 m (step S2).
6).

If it is determined in step S21 that the subject has a contrast (if it is not a low contrast), the distance measurement result L and the amount of reflected signal ip are determined in step S22.
Calculate the reflectance from. Note that if the reflected signal light amount ip is smaller than the distance measurement result L, it is considered to be low reflectance, and if it is large, it is considered to be high reflectance. Here, assuming that the reflectance is constant, the reflected signal light quantity ip is represented by the distance measurement result L assuming that ip = A / L ＾ 2 (A is a constant), so that the reflection is calculated by calculating ip × L ＾ 2. The rate can be estimated.

The reflectivity is thus obtained. If the reflectivity is low (S23), exposure compensation on the minus side is performed (step S28), and if the reflectivity is high (step S24). After performing the exposure correction on the plus side (step S29), the focus is set on the distance measurement result L (step S30), and the exposure operation is performed (step S3).
1).

In general, the exposure of the camera is calculated so as to be appropriate for a subject having a standard reflectance. Without such a correction, a white object or a black object is photographed as gray. . As described above, the camera including the distance measuring apparatus according to the fourth embodiment takes such a point into consideration, and can provide an automatic exposure camera that can accurately reproduce the color tone of the subject.

In addition, even if the conventional passive autofocus is not good, the subject can be correctly focused, and the AF
Since the photometric sensor is also built in the module 11, it is possible to provide a small and high-performance camera.

The present invention can be applied to a photometric device for controlling camera exposure, and an effective embodiment will be described below.

FIG. 13 is an explanatory diagram showing a sensor configuration of a photometric device for camera exposure control according to a fifth embodiment of the present invention.

As shown in the figure, in the photometric device of this embodiment, the passive autofocus area sensor 32 is used.
A third sensor 32c for receiving a remote control signal or for average photometry is disposed between a and 32b.

Conventionally, a technique for performing photometry using an autofocus sensor is known. However, an autofocus sensor can only perform photometry in a narrow field of view because it only looks at distance measurement points in a photographic screen.

The camera system equipped with the photometric device of the fifth embodiment has been made in view of such circumstances, and a third sensor 32c provided at an intermediate position is provided with a dedicated third lens 31c. The shape design of the third lens 31c and the third sensor 32c makes it possible to appropriately select the photometric range.

In the IC chip 32 for autofocus provided with the area sensors 32a and 32b as employed in the fifth embodiment, the output processing of the sensor is generally provided near the area sensor arrays 32a and 32b. Circuits 42a and 42b are often arranged adjacent to each other. Therefore, also in the present embodiment, the third
Although the shape of the sensor 32c must be elongated, the use of the third lens 31c as a cylindrical lens makes it possible to measure light in a wide area different from the sensor shape.

When the photometric operation described above is performed by the light receiving lenses 1a and 1b, which are autofocus lenses, noise light enters from outside the distance measurement range, and the autofocus accuracy deteriorates. Therefore, it can be said that the use of the wide-angle lens as in the present embodiment is an advantage caused by providing the third sensor 32c.

According to the present embodiment, for example, it is detected whether or not the subject 6 is backlit in a scene as shown in FIG. 14, and when the subject is backlit, a strobe is emitted to darken the face of the subject 6. Can be prevented. In FIG. 14, a portion indicated by reference numeral 41 is a portion which can be measured by the third lens 31c and the third sensor 32c.
A portion indicated by 0 is a portion which can be measured by a part of the sensor array 32a which is originally a sensor for distance measurement.

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

First, spot photometry is performed on an area indicated by reference numeral 40 in FIG. 14 in a part of the sensor array 32a (step S41). Next, the area indicated by the same reference numeral 41 is subjected to average photometry using the third sensor 32c (step S42). Then, based on the result, it is determined whether or not the subject 6 is under a backlight condition (step S43). More specifically, if the spot metering result with respect to the average metering value is equal to or less than a predetermined level, it is determined that the subject is backlit, and flash photography is performed accordingly (step S44). Step S45) is performed.

As described above, according to the camera system provided with the photometric device of the fifth embodiment, it is possible to take clear pictures even in a backlight scene by using spot photometry and average photometry. In addition, since all of these determination sensors can be accommodated in the autofocus module 11 in the first embodiment and the like, the size of the camera is not increased.

The third embodiment employed in this embodiment
The technical means for increasing the light receiving angle by the characteristic of the lens 31c is also effective when the third sensor 2c is used as a remote control signal receiving sensor.

Next, in order to clarify the difference between the two types of sensors used in the above embodiments, with reference to FIG.
A sensor array 2 ′ that forms a passive autofocus sensor array, for example, the sensor arrays 2 a and 2 b,
A third sensor 2 located intermediate the two sensor arrays
An embodiment of a circuit that processes each of the c will be described.

In this processing circuit, the output of the sensor array 2 ′ constituting the sensor arrays 2 a and 2 b for measuring the luminance distribution of the subject is input to the negative input terminal of the integrating amplifier 50 and connected to the integrating capacitor 51. And integrated by the capacitor 51. A switch 52 is connected to both ends of the integration capacitor 51, and the integration by the integration capacitor 51 is started by turning off the switch 52.

A reference voltage Vref1 is applied to the + input terminal of the integrating amplifier 50.
The output voltage Vint of 0 is input to the negative input terminal of the comparator 53. This comparator 5
3, the comparison voltage Vref2 is applied to the + input terminal. Further, the output of the comparator 53 is a timer 5
4 is connected to the CPU 10.

That is, the output current of the sensor array 2 ′ is input to the integration amplifier 50, and the integration of the integration capacitor 51 is started by the OFF operation of the switch 52. This integration is: When the switch 52 is turned on, the integration capacitor 51 is initialized to the reference voltage Vref1, and the output voltage Vint of the integration amplifier 50 becomes Vref1.
Will be the same as

When the switch 52 is turned off and the integration is started, the output voltage Vint of the integration amplifier 50 changes to the level shown in FIG.
It changes as shown in FIG. When the output voltage Vint reaches the comparison voltage Vref2 of the comparator 53,
The output of the comparator 53 is inverted.

Assuming that the interval between the turning off of the switch 52 and the inversion timing of the comparator 53 is the integration time Tint, when the photocurrent is small, the Tint becomes long and the luminance becomes low. On the other hand, when the photocurrent is large,
Since int becomes short, if this time is designed and detected by the timer 54, a signal based on luminance can be obtained.

On the other hand, the output terminal of the third sensor 2c used for active autofocus or for receiving a remote control signal is connected to the CPU 10 via the amplifying circuit 56 and the processing circuit 57 following the AC coupling circuit 57b. I have. Thus, of the optical output signal of the third sensor 2c, the DC component of the light is not amplified and only the AC component is amplified.

Therefore, the signal light for active autofocus emitted in a pulse shape and the signal light from the remote control are separated from the background light to reduce the influence of noise and to be detected with high accuracy. Become.

As described above, according to the above-described embodiment, the third sensor is efficiently arranged in a compact space, and this sensor is used to perform active autofocus of the light projection type, remote control, and photometry. By providing such a function, it is possible to provide a smaller camera or a camera with the same size and higher functionality.

[Appendix] According to the embodiment of the present invention as described in detail above, the following configuration can be obtained. That is, (1) two light pattern signals from a subject received from two light paths with parallax are received by two sensor arrays arranged on the same semiconductor chip, and the two light pattern signals are received by the two parallaxes of the two light patterns. In a distance measuring apparatus for measuring a subject distance from an amount of displacement based on the third optical sensor, a third optical sensor is disposed between the two sensor arrays, and the third optical sensor has a signal of a different wavelength from the two sensor arrays. 1. A distance measuring device comprising an optical filter for receiving an optical signal, and capable of preferentially detecting an optical signal of a specific wavelength.

According to the distance measuring apparatus described in (1), in a so-called passive AF, a dead space between two optical sensors can be effectively used, and a signal having a wavelength different from the wavelength detected by the passive AF can be used. Detection can be performed with high accuracy without being affected by noise.

(2) The distance measuring device according to (1), wherein the third optical sensor is used as a light receiving element for a remote controller.

According to the distance measuring apparatus described in (2), 2
Since the remote control light-receiving element can be arranged in the dead space between the two optical sensors, the entire device can be downsized.

(3) Two light pattern signals from a subject which are received from two light paths with parallax are respectively received by two sensor arrays arranged on the same semiconductor chip. In a distance measuring apparatus for measuring a distance to the subject from a displacement amount based on the parallax, a third device is provided on the same chip between the two sensor arrays.
And a means for calculating information on the subject based on the third light sensor output difference between when the light emitting means emits light and when the light emitting means does not emit light. Distance device.

According to the distance measuring apparatus described in (3), in the so-called passive AF, by arranging the active AF optical sensor in the dead space between the two optical sensors, this space can be effectively used. Further, by using the output difference of the third optical sensor between when the light emitting means emits light and when it does not emit light, the light is not affected by the background light.
A signal component based on the light emission of the light projecting means can be accurately extracted.

(4) The distance measuring apparatus according to (3), wherein the third optical sensor doubles as a light receiving element for exposure control.

According to the distance measuring apparatus described in (4), since the third optical sensor is used not only as a light receiving element for active AF but also as a light receiving element for exposure control, the overall size of the apparatus can be reduced. Can be planned.

(5) Two light pattern signals from a subject received from two optical paths with parallax are received by two sensor arrays arranged on the same semiconductor chip, and the parallax of the two light patterns is obtained. In a distance measuring apparatus for measuring a subject distance based on a displacement amount based on a distance, a third optical sensor is disposed between the two sensor arrays, and an optical system that guides light to the third optical sensor includes the first optical sensor. A distance measuring device having optical characteristics different from those of the second optical sensor optical system;

According to the distance measuring apparatus described in (5), in a so-called passive AF, the dead space between two optical sensors can be effectively utilized, and the passive AF is arranged in the dead space with the light receiving optical system of the passive AF. The light receiving optical characteristics of the optical sensor can be changed, and the detection range can be easily changed.

(6) In a camera having a light projecting means and a light measuring means, a detecting means capable of detecting the output of the light measuring means by separating it into a steady light component and a pulse light component; Using the output of the photometric means at the time of light emission,
A camera, comprising: arithmetic control means for determining a distance to a subject and an exposure control condition.

According to the camera described in (6), the exposure control condition can be determined based on the steady light component, and the subject distance can be determined based on the pulse component light. The distance and the exposure control can be determined using the output of one photometer, which is useful for downsizing the camera.

(7) The camera according to (6), wherein the light projecting means is a flash device of the camera.

According to the camera described in (7), the strobe means can be used as the light emitting means.
Useful for downsizing cameras.

(8) The camera according to (6), wherein the photometry means is built in a distance measurement means having two sensor arrays and is formed on the same chip.

According to the camera described in (8), since the sensor array of the distance measuring means is also used as the light measuring means, it is useful for downsizing the camera.

(9) A passive type in which two light patterns from a subject received from two optical paths with parallax are received by two sensor arrays, and a subject distance is determined from a shift amount of the two light patterns based on the parallax. Focus detecting means, light projecting means for projecting light for distance measurement toward the subject, a third optical sensor arranged between the two sensor arrays for receiving the light for distance measurement, and the passive means Determining means for determining the subject distance based on either the output of the focus detection means or the output of the third optical sensor.

(10) The distance measuring device according to (9), wherein the light projecting means is an infrared light emitting diode or a flash light emitting device.

(11) The distance measuring device according to (9) or (10), wherein the third optical sensor is a light receiving position detecting element, and detects the subject distance based on the light receiving position of the distance measuring light. .

(12) The third optical sensor is an element for outputting a signal corresponding to the amount of received light (9) or (10)
3. The distance measuring device according to 1.

(13) The light projecting means has a plurality of light projecting sections, and detects the subject distance based on the magnitude of the received light amount and the combination of the light projecting sections at this time (9) or (1).
The distance measuring device according to 0).

(14) The distance measuring apparatus according to (9) or (10), wherein the subject distance is detected based on the amount of light received by the light receiving means.

(15) The distance measuring device according to any one of (9) to (14), further comprising a processing circuit for separating a steady light component and a signal component based on the distance measuring light from the output of the light receiving means.

(16) The distance measuring apparatus according to any one of (9) to (15), wherein the sensor array and the third optical sensor are formed on the same semiconductor chip.

(17) The distance measuring apparatus according to any one of (9) to (16), wherein the third optical sensor also serves as a light receiving sensor for a remote controller.

(18) The output of the third optical sensor is
If the remote control mode is selected, the output of the third optical sensor is connected to the remote control processing circuit and the focus detection circuit, and the output of the third optical sensor is connected to the remote control processing circuit. If the mode is not selected, it is connected to the focus detection circuit (1
The distance measuring device according to 7).

(19) The distance measuring device according to any one of (9) to (16), wherein the third optical sensor also serves as a light receiving element for measuring the luminance of the subject.

(20) The distance measuring apparatus according to (19), further comprising an exposure control means for calculating the reflectance of the subject from the measured subject brightness and the determined subject distance and performing exposure correction.

(21) Two light patterns from a subject received from two optical paths with parallax are received by two sensor arrays via two light receiving lenses, and the two light patterns based on the parallax are used to calculate the amount of deviation between the two light patterns. Passive focus detection means for determining a subject distance, a third optical sensor disposed between the two sensor arrays, and a light receiving range of the two light receiving lenses disposed on the third optical sensor. A wide third light receiving lens, and performs spot metering based on the output of the sensor array, and performs a wider range of metering than the spot metering based on the output of the third optical sensor. Features camera.

(22) The camera according to (21), wherein the two sensor arrays and the third optical sensor are formed on the same semiconductor chip.

(23) The third optical sensor is provided with the second optical sensor.
Unequally spaced between two sensor arrays (21)
Or the camera according to (22).

(24) Two light patterns from a subject received from two light paths with parallax are received by two sensor arrays, the DC output photocurrents of the sensor arrays are integrated, and the output of each array is converted to a digital value. Means for calculating a subject distance from the digital signal; a third sensor provided on the same chip as the two sensor arrays; and a pulse-like signal of the third sensor output signal light. Pulse light processing means for separating and evaluating only the components of the above, and detecting means for detecting an optical signal of a remote control device for controlling a camera according to an output of the pulse light processing means or a distance measuring light emitted from the camera side. Camera.

[0152]

As described above, according to the present invention, it is possible to provide a compact, high-performance, high-performance distance measuring apparatus and camera.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a distance measuring apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing output distributions of respective sensors constituting two passive autofocus sensor arrays in the distance measuring apparatus of the first embodiment.

FIG. 3 is a diagram illustrating detection of a shift amount between two light patterns based on parallax in the distance measuring apparatus according to the first embodiment.

FIG. 4 is an explanatory diagram of an interpolation calculation process in the distance measuring apparatus of the first embodiment.

FIG. 5 is a diagram illustrating the principle of an active type autofocus.

FIG. 6 is an explanatory diagram illustrating a schematic configuration of a camera system including a distance measuring device according to a second embodiment of the present invention.

FIG. 7 is a flowchart showing an operation of the distance measuring apparatus according to the second embodiment.

FIG. 8 is a view showing one scene for explaining setting of a focusing distance in the distance measuring apparatus of the second embodiment.

FIG. 9 is an explanatory diagram showing a schematic configuration of a distance measuring apparatus according to a third embodiment of the present invention.

FIG. 10 is a flowchart showing an operation of the distance measuring apparatus according to the third embodiment.

FIG. 11 is an explanatory diagram showing a configuration of a camera system including a distance measuring apparatus according to a fourth embodiment of the present invention.

FIG. 12 is a flowchart showing an operation of the distance measuring apparatus according to the fourth embodiment.

FIG. 13 is an explanatory diagram showing a sensor configuration of a photometric device according to a fifth embodiment of the present invention.

FIG. 14 is a diagram showing one scene measured by the photometric device of the fifth embodiment.

FIG. 15 is a flowchart showing the operation of the photometric device according to the fifth embodiment.

FIG. 16 shows a third example of the distance measuring apparatus according to the first embodiment.
It is explanatory drawing regarding the arrangement | positioning of a sensor.

FIG. 17 is employed in the apparatus of each of the above embodiments.
FIG. 5 is an electric circuit diagram showing an embodiment of a passive autofocus sensor array and a circuit for processing each of a third sensor.

FIG. 18 is a diagram showing a relationship between an output value of an integrating amplifier and a comparator in the circuit shown in FIG. 17;

[Explanation of symbols]

 1a, 1b: Light receiving lens 1c: Third light receiving lens 1d: Visible light cut filter 2: Semiconductor chip 2a, 2b: Sensor array for passive auto focus 2c: Third sensor 3a, 3b ... 4: A / D converter 5 arithmetic circuit 6 subject 7 AF circuit 8 IRED drive circuit 8a IRED 9 floodlight lens 10 CPU 11 passive autofocus module

Claims (3)

[Claims] 1. A passive focus that receives two light patterns from a subject received from two optical paths with parallax by two sensor arrays, and determines a subject distance from a shift amount of the two light patterns based on the parallax. Detecting means; light projecting means for projecting light for distance measurement toward the subject; third optical sensor arranged between the two sensor arrays for receiving the light for distance measurement; Determining means for determining the subject distance based on either the output of the focus detecting means or the output of the third optical sensor. 2. The distance measuring apparatus according to claim 1, wherein said third optical sensor also serves as a light receiving element for a remote control transmitter or a photometric element for exposure control. 3. Two light patterns from a subject received from two optical paths with parallax are received by two sensor arrays via two light receiving lenses, and the two light patterns based on the parallax are received.
Passive focus detection means for determining a subject distance from the amount of deviation of the two light patterns; a third light sensor disposed between the two sensor arrays; and a second light sensor disposed on the third light sensor A third light receiving lens having a light receiving range wider than the two light receiving lenses, and performing spot light metering based on the output of the sensor array; Camera.