JP2001249268A - Range finder for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera range finder capable of accurately focusing on an object even if the object lies anywhere in a screen. SOLUTION: The range finder is provided with 1st light receiving elements 601 and 602 for receiving the light of the image signal of the object, a light projecting element 501 for projecting range finding light, a 2nd light receiving element 502 constituted of plural light receiving surfaces for projecting the range finding light on the object and receiving the signal light of the range finding light reflected by the object, and a CPU 11 for selecting the light receiving surface for receiving the light reflected by the object out of the surfaces of the 2nd light receiving element 502 in accordance with the image signals from the 1st light receiving elements 601 and 602.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a camera distance measuring device.

[0002]

2. Description of the Related Art An active type distance measuring device (active AF) that emits distance measuring light from a camera, receives reflected signal light from the camera, and measures a distance, and uses an image signal of a subject. 2. Description of the Related Art A passive type distance measuring device (passive AF) for performing distance measurement is conventionally known.

Japanese Patent Laid-Open Publication No. Hei 10-229516 discloses a distance measuring device for a camera that combines an external light AF (active AF) and a contrast AF (passive AF). If not, the external light AF is adopted according to the photographing environment such as the temperature, the aperture, and the focal length.
It discloses that a combination of F and contrast AF is adopted.

[0004]

However, what is important when actually taking a picture with a camera is that the main subject exists at any position on the screen rather than simply the effectiveness of the distance measuring device in the mode or shooting environment. It is to know exactly which distance measurement method is most effective for the main subject.

The present invention has been made in view of such a problem, and an object of the present invention is to accurately focus on a subject regardless of the position on the screen where the subject exists. An object of the present invention is to provide a camera distance measuring device.

[0006]

According to a first aspect of the present invention, there is provided a distance measuring apparatus for a camera, comprising: first light receiving means for receiving an image signal of a subject; And a second light receiving surface comprising a plurality of light receiving surfaces for projecting the distance measuring light to the subject and receiving reflected signal light of the distance measuring light from the subject. Means and the first
Selecting means for selecting a light receiving surface of the second light receiving means for receiving the reflected light from the subject in accordance with the image signal from the light receiving means.

According to a second aspect of the present invention, in the distance measuring apparatus for a camera according to the first aspect, the selecting means detects a color or brightness change point of the image signal from the first light receiving means.

According to a third aspect of the present invention, in the camera distance measuring apparatus according to the first aspect, the first light receiving means is a photographing CCD for recording a digital electronic image.

A fourth invention is a distance measuring device for a camera, comprising: first light receiving means for receiving an image signal of a subject; light emitting means for emitting light for distance measurement in a plurality of directions; Light-receiving means for projecting the distance-measuring light to the subject and receiving reflected signal light from the subject; determining means for determining an image signal of the first light-receiving means; Selecting means for selecting at least one of the plurality of light projecting directions according to the output.

According to a fifth aspect of the present invention, there is provided a distance measuring apparatus for a camera, the image signal outputting means for outputting an image signal of a subject, the light projecting means for projecting distance measuring light toward the subject, The image processing apparatus includes a subject portion for obtaining a subject distance based on an image signal, and a classification unit for classifying the subject into a subject portion for which the subject distance is required based on a reflection signal at the time of light projection of the light projecting unit.

According to a sixth aspect of the present invention, in the camera distance measuring apparatus according to the fifth aspect of the present invention, the distance measuring method is switched for each object portion classified by the classification means, and the distance is measured. The apparatus further includes a determination unit that determines a focus position according to the result.

According to a seventh aspect of the present invention, there is provided a distance measuring apparatus for a camera, wherein the light projecting means projects light for distance measurement to an object, an image signal output means for detecting an image signal of the object, and the image signal. Selecting means for selecting a distance measuring area in which distance measurement is to be performed by the light emitting means based on an output from the output means.

An eighth aspect of the present invention is a camera having a function of performing automatic white balance control, wherein the light projecting means projects light for distance measurement to a subject, and the light receiving means receives a reflected signal from the subject. , According to the brightness of the main subject,
And a correcting means for correcting the output of the light receiving means when controlling the light projecting means to obtain focusing information.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an arrangement for active AF and passive AF is provided, an image signal is detected in advance by passive AF, and each object on the screen is referred to by referring to the obtained image signal. It is determined whether the active AF is suitable or the passive AF is suitable, the distance is measured at a plurality of points by using an appropriate ranging method according to the determination result at this time, and then the main subject is determined according to the obtained ranging result. It is characterized in that a distance is determined and focusing is performed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First Embodiment) FIG. 1A is a diagram showing a configuration of a first embodiment of the present invention. In the camera of the present embodiment, the focusing means 14 is controlled under the control of the CPU 11.
In controlling the focusing of the photographing lens 14 by a, two distance measurement methods, active and passive, are selectively used. In the active AF, light from a plurality of light projecting elements 501 selectively driven by a selection driver 505 is projected to a subject 610 as distance measuring light via a projection lens 503, and reflected signal light from the subject 610 is reflected. The light receiving lens 5
The light is received by a light receiving element (second light receiving means) 502 via the light receiving element 04. The AFIC 500 includes the CPU 11 and the light emitting element 5.
01, an IC arranged between the light receiving element 502 and
A timing circuit, a ratio calculation circuit, a light amount determination circuit,
It includes an amplifier, a stationary light removal circuit, and the like.

In the passive AF, light from the subject 610 is received by light receiving elements (first light receiving means) 601 and 602 through a pair of light receiving lenses 603 and 604 to form an image signal of the subject 610. . The obtained image signal is represented by A
After being converted into a digital signal by the / D conversion unit 605,
Input to PU11. A pair of light receiving lenses 603 and 604
A pair of image signals obtained as a result of the parallax difference in position has a relative position difference depending on the distance of the subject 610, and the CPU 11 determines the subject distance based on this.

The details of the two AF methods will be described below with reference to FIGS. 2 (a) and 2 (b). FIG.
(A) is a block diagram of active AF. The distance measuring light projected from the light projecting element 501 such as an infrared light emitting diode (IRED) through the light projecting lens 503 is reflected by the subject 610 and enters the light receiving element 502 through the light receiving lens 504. . When an element called a light position detecting element (PSD) is used as the light receiving element 502, an output current depending on the light incident position x flows out of the two electrodes, and the object distance L is obtained by calculating this current.

First, the light incident position x will be described.
As is clear from FIG. 2A, since the relationship of L: S = f: x is established by the principle of triangulation, x = S · f
/ L. Here, S · f is a distance between the lenses (base line length) and the focal length of the light receiving lens, and is a fixed value. Therefore, it can be seen that x is uniquely determined by a change in the subject distance L.

A pair of output currents of the light position detecting element (PSD) 502 depends on the incident light position x and the incident light intensity. Therefore, after a pair of output currents are amplified by the amplifiers 511a and 511b, the amplified signal from the amplifier 511a is input to the ratio calculation circuit 512, and the amplified signal from the amplifier 511b is input to the light quantity determination circuit 513. Ratio calculation circuit 51
Reference numeral 2 denotes a circuit for calculating a ratio of two currents, whereby the CPU can determine information depending on the light incident position x. The light amount determination circuit 513 determines whether the PSD 50
2 is a circuit for adding two amplified current signals in order to form a signal corresponding to the amount of signal incident on the signal 2.

Further, in addition to the amplifier, each electrode of the PSD 502 has a stationary light removing circuit 51 for removing components other than signal light.
0a and 510b are connected. The determination of the current based on the signal light and the other light is performed based on the fact that one is pulse light and the other is stationary light. Therefore,
A drive current corresponding to the pulse signal generated by the timing circuit 507 is supplied to the IRED 501 via the driver circuit 505.

By the way, the signal light current depends on the distance to the subject and the reflectance, if the amount of the projected light is constant. Therefore, if the reflectance is constant, the object distance L can be obtained by examining the signal light current at that time by the light amount determination circuit 513.

In the above, the ratio calculating circuit 512 and the light amount determining circuit 513 have been described. The former has a small dependency on reflectivity, but the calculation is complicated, so that if the S / N deteriorates at a long distance, the accuracy is significantly reduced. On the other hand, the latter is simple, so that the distance is measured to a relatively long distance. There is an advantage that it is possible. As described above, even in the active AF, it is necessary to use the system in various ways. AFIC5 in FIG.
Reference numeral 00 denotes an analog circuit having such an amplification operation function.

Referring now to FIG. 2B, a passive AF
The principle of will be described. Basically, triangulation is used. Here, the base line length is set to B as shown in FIG.
Assuming that the focal length of 3,604 is f, light from the subject 610 forms an image on each of the sensor arrays 601 and 602 with a relative positional difference of x. After the CPU converts the image signal into a digital signal using the A / D converter, x is obtained by comparing the two image signals. However, when the subject 610 has no contrast or insufficient illumination, Does not require a clear difference and cannot perform accurate ranging. In this regard, the active AF has a contradictory feature that the distance can be accurately measured when the subject has no contrast.

Therefore, in the present embodiment, the active AF is strong against low contrast (low contrast) and the passive AF is strong against contrast, and the two AF methods are used effectively to achieve more accurate focusing. It is intended to achieve alignment. The CPU 11 in FIG.
An arithmetic control means for performing focusing by properly using these two distance measuring methods, and is composed of a one-chip microcomputer or the like.

The selection of the two distance measurement methods will be described below by taking a specific shooting scene as shown in FIGS. 4A and 4B as an example. In the scene of FIG. 4A, a large contrast is recognized in the background tree 630 and the clothes of the main subject 610 in the screen 607, but the face of the main subject 610, which is an important subject, is low contrast. Is shown. FIG. 4B shows an example in which an important subject exists in a portion other than the low contrast.

In the present embodiment, the distance measuring unit 608 of the screen 607 is divided into two regions 1 and 2 for a contrasted portion and a low contrast portion, and different methods are used for each region according to a distance measuring sequence shown in FIG. The distance is measured by using.

FIG. 3 is a flowchart for explaining details when the CPU 11 of FIG. 1A controls the distance measuring sequence. In FIG. 3, first, step S1001
Is a step of inputting an image signal of a subject using the sensor array 601 of the passive AF.
2, according to the contrast pattern from the image signal
This is a step of classifying each part of the ranging area.

If, for example, an image signal as shown in FIG. 1B is obtained in the passive AF, it is possible to discriminate between a low-contrast portion and a portion having contrast in the screen. In many conventional cameras, the distance was often measured in the passive AF except for the low contrast portion.
When the low contrast portion is an important subject as in (a), accurate focusing could not be performed.

Therefore, in the present embodiment, step S100
2, for the portion determined to be low contrast, a plurality of IREDs 501 and PSDs 502 are selected, and the distance of the subject 610 is measured by active AF (step S1003).
For the parts other than the low contrast, the distance is measured by the passive AF (step S1004), and then in step S1005, the focus is adjusted to the point at which the closest distance is output. This processing is performed by the CPU 11 of FIG. 1A controlling the photographing lens 14 via the focusing means 14a.

As described above, FIG. 4A or FIG.
In any of the scenes (b), active AF is performed on the low contrast portion, passive AF is performed on the portion having contrast, and then the focus is adjusted to the closest point. Regardless of the subject, the subject can be accurately focused.

FIG. 5A is a diagram showing a configuration of a modification of the first embodiment. In the present invention, the active AF can be performed using the light of the strobe 20, as shown in FIG. 5A, without using the IRED or the PSD. At this time, the light amount AF may be performed by comparing the amount of light incident on the sensor array at the time of strobe light emission and at the time of no strobe light emission. A / D converter 6 converts only signal light generated by
By performing A / D conversion according to the method 05, the signal light amount can be detected more easily, and the distance measurement based on the principle of the active AF can be performed in accordance with the principle of the light amount AF. That is, in this case, the passive sensors 601 and 602 are
It has a function as an application sensor.

FIG. 5B is a flowchart for explaining the details of focusing control using a strobe.
First, in step S1010, an image signal is input using a sensor output without removal of steady light, and in the next step S1011 the area is divided into two types. Here, the area without contrast is measured as the area A by the active AF, and the area with contrast can be divided into the area B because the distance can be measured by the passive method.

Step S1012, Step S1013
Is a step of measuring the distance of each area in a manner appropriate to it. In step S1012, a focusing distance LA is acquired based on the amount of signal light reflected by emitting a strobe light to the area A. At this time, the reflectance of the subject is assumed to be a standard value of about 18%. Step S1
At 013, passive AF is performed on the area B to obtain a focusing distance LB.

In step S1014, focusing is performed by comparing the distance measurement results LA and LB thus obtained. That is, if LA is larger than LB in step S1014, the flow advances to step S1016 to set LB to the focus distance, and if LA is smaller than LB, the flow advances to step S1015 to set LA to the focus distance. . Then, in step S1017, focusing is performed.

In this way, as in the example of FIG. 1, accurate focusing can be performed regardless of the composition of the subject. Also,
Since an IRED or PSD is not required, an active-only light emitting / receiving lens is not required, thereby enabling a compact design.

FIG. 6 is a flowchart for explaining another example of the focusing control. In this example, the ranging area is divided into areas 1 and 2 from the beginning instead of being divided with or without contrast, and a ranging method suitable for the area is sequentially selected depending on whether or not there is contrast in that part. To do. After inputting the image signal in step S1020, the contrast of each of the regions 1 and 2 is sequentially determined in steps S1021 and S1023. If there is contrast, passive AF is performed to calculate L1 and L2 (steps S1022 and S1024).

Next, in step S1025, it is determined whether L1 has already been calculated. In step S1027, it is determined whether L2 has been calculated. If not, step S1026 (if L1 has not been calculated), step S1028 (If L2 has not been calculated), distance measurement is performed by the active method.

In steps S1029 to S1032, FIG.
The focusing distance is determined by the same method as in (b). According to such a method, there is an advantage that a complicated area division determination can be omitted.

(Second Embodiment) When a person 610 in front of a night view as shown in FIG. 7A is photographed, a part where a person's face and background are mixed in a distance measurement area 608 in a screen 607. In some cases, the contrast of the edge of the contour portion is increased, and a portion other than the face and the background is focused.

Therefore, in the second embodiment, in order to overcome such a scene, in a scene as shown in FIG. 7A, the distance measuring area is divided into three parts as shown in FIG. Distance measurement is performed using a passive AF and an active AF for a total of three portions, that is, a contrast portion sandwiching the contrast of the edge of the portion and a portion divided into two portions with the edge of the contour portion interposed therebetween.

Here, the relationship between a subject having contrast and active AF will be described.

In FIG. 8A, when the projector 501 is projected on the subject 505 via the projection lens 503,
In the triangular distance measurement (ratio calculation) due to the contrast of the reflectance of the object 505 and the lack of the light spot due to the deviation from the object 505 as shown in the figure, the incident position on the PSD 502 shifts, resulting in erroneous distance measurement.

Further, as shown in FIG. 8B, since a part of the predicted light flux does not return, even if the amount of light incident on the PSD 502 is reduced and a small amount of AF is performed, erroneous distance measurement is performed.

Therefore, in the present embodiment, it is determined that the reliability of the distance measurement result when the active AF is performed on the contrast change point is low, and the contrast change point is determined as in step S1043 in FIG. Active AF only for positions (in FIG. 7B) that do not include
To do. For example, the active light receiving element is of a split type, and light amount AF is performed using only light incident on a portion 608a of a plurality of distance measurement areas 608 as shown in FIG. 9B.

Further, the distance measuring device is unitized, and FIG.
As shown in FIG. 9C, the light may be emitted only to the portion 608a in FIG. 9B by rotating the gear 510 to control the light emitting direction.

FIG. 9A is a flowchart for explaining the operation of the second embodiment. Step S
Steps 1040 to S1041 are steps for detecting a change point of the contrast in the ranging area. Step S
In step 1042, the point of change in contrast is measured by passive AF to obtain a distance measurement result L3. In step S1043, the distance that does not include the contrast change point is measured by the active AF as described above, and the distance measurement results L1, L
Get two.

Next, in step S1044, the distance measurement result L1,
After the focusing distance is determined based on L2 and L3, the focusing control (step S1045) is performed.
Accurate focusing can be performed even in a case where a distance is measured in a scene including a dimly lit person in front of a large contrast night view as shown in FIG.

As an example of the determination of the distance determination in step S1044, the passive A shown in FIG.
The result of F shows the intermediate distance between the person and the background,
Since the active AF of the portion indicates the correct distance measurement result, in this case, a simple method of giving priority to the distance measurement result at a short distance may be used.

(Third Embodiment) Recently, a camera has been proposed in which a digital still image is stored in a memory using an image pickup device such as a CCD. In such a camera, the CCD for imaging directly serves as an image detection unit for passive AF, and furthermore, it is possible to extract more advantageous scene information such as two-dimensionally arranged pixels or adding color information. Can be.

FIG. 10 is a diagram showing a configuration of a third embodiment in which the present invention is applied to a digital camera. Here, the light receiving element 502 for active AF is configured to be divided into areas. Behind the taking lens 14, an aperture 9b controlled by the aperture control means 16, an optical path dividing means 506 for a finder, and an imaging device (CCD) 23 controlled by the imaging control unit 22 are arranged in this order. CCD
The image signal captured at 23 is recorded in the recording unit 25.
Further, the captured image can be displayed on the display unit 19.

The CPU 11 controls the sequence of the entire camera, and performs distance measurement, focusing control, and strobe light emission control in addition to driving and controlling the CCD 23 and image display control.

FIG. 12A is a flowchart for explaining the operation of the third embodiment. FIG. 12 (b)
Indicates a state where the user holds the digital camera. 14 is a photographing lens, 503 is a light projecting lens, 504 is a light receiving lens, and 600 is a lens barrel.

When the aperture 9b is fully open, the CCD 23
Since only a large blurred image is incident on the aperture, the aperture is first reduced to a small value in step S1050 in this embodiment.
After increasing the contrast of the image on the CCD 23, the CCD
The signal of the image 23 is input (step S1051).

After returning the aperture to the original in step S1052, the flow advances to step S1053 to determine the main subject based on the acquired image pattern (pattern determination). As a detection method, a circle detection method using a round head,
A neck detection method using a difference in width between a neck and a shoulder is known.

After the main subject determination, it is determined whether the main subject is a low contrast or not (step S105).
4) If it is a low contrast, step S1054 is branched to Y, and in step S1056, the area of the low contrast pattern portion is selected and the distance is measured by active AF. As described above, the third embodiment is different from the previous embodiment in that the acquired image information is effectively used, the main subject is first checked, and then the distance measurement method is switched.

When it is determined in step S1054 that the object is not low contrast, that is, for a subject having a contrast, the focusing lens is moved while judging the sharpness of the contrast, and the jaspin position is determined to perform lens control. Focus control is performed in the “hill climbing AF” to be performed (step S1055). This method measures the distance by judging the image signal as in the passive method, but is not a triangulation.

In the active AF described above, a strobe light is projected, and the distance may be determined using only the light amount of the selected area as shown in FIG. 11, or the light may be projected as shown in FIG. 8C. The element 501 is made movable, and the area 502 in FIG.
After controlling the light projection direction to the area 502b selected from a, the distance measurement based on the reflected signal light amount may be performed. With such a measure, it is possible to detect a correct reflected light amount and prevent erroneous distance measurement as described with reference to FIG.

In the above sequence example of FIG. 12A, in step S1056, the reflected light amount A at the time of flash emission is used.
F is performed to correct the light amount according to the selected area. If the size of the area is not controlled, a large amount of light returns from a subject having a large area and a small amount of light returns from a subject having a small area under a wide range of illumination of the strobe. In this embodiment, the correction based on the reflection area (normalization by the area) is performed to improve the accuracy.

According to the third embodiment, since the distance is measured by the imaging means in consideration of the size and position of the main subject, accurate distance measurement and focusing can be performed regardless of the position and contrast of the subject. .

Also, a white balance technique for determining the exposure amount based on the distribution of shades of the entire screen image to make a white object white is known. However, if this technique is used, a main subject limited within the screen is limited. From the brightness of the image, it is possible to predict the degree of reflectance with respect to white.

FIG. 13 is a flowchart showing a modification of FIG. In this modified example, after the white balance is determined in step S1064, the process proceeds to step S106.
Since the reflectance of the main subject is predicted in step 5 and the result of the light amount AF is corrected in step S1068 according to the result, the error of the reflectance can be further reduced to achieve more accurate focusing.

As described above, according to the first to third embodiments, the active AF and the passive AF can be effectively used separately to provide an autofocus camera capable of accurately focusing even when a subject is located at any position on the screen. Can be provided.

[0064]

According to the present invention, it is possible to provide a camera distance measuring apparatus that can accurately focus on a subject regardless of the position of the subject on the screen.

[Brief description of the drawings]

FIG. 1A is a diagram illustrating a configuration of a first embodiment of the present invention, and FIG. 1B is a diagram illustrating an example of an image signal obtained in a passive AF.

FIG. 2 is a diagram for describing details of two AF methods.

FIG. 3 is a flowchart illustrating details when the CPU 11 of FIG. 1A controls a distance measurement sequence.

FIG. 4 is a diagram showing an example of a scene including a part having contrast and a low contrast part.

FIG. 5A is a diagram illustrating a configuration of a modified example of the first embodiment, and FIG. 5B is a flowchart illustrating details of focusing control using a strobe;

FIG. 6 is a flowchart for explaining another example of focus adjustment control.

FIG. 7A is a diagram for explaining a conventional problem corresponding to the second embodiment of the present invention, and FIG. 7B is a diagram for explaining a method of the second embodiment for solving the problem. FIG.

FIG. 8 is a diagram for explaining weak points of active AF and a method for solving the weak points.

FIG. 9A is a flowchart for explaining the operation of the second embodiment of the present invention, and FIGS. 9B and 9C are diagrams for explaining a method for overcoming the weak point of the active AF. .

FIG. 10 is a diagram showing a configuration of a third embodiment in which the present invention is applied to a digital camera.

FIG. 11 is a diagram showing a selected area.

FIG. 12 is a flowchart for explaining the operation of the third embodiment of the present invention.

FIG. 13 is a flowchart showing a modified example of FIG.

[Explanation of symbols]

 1 CPU 14 Shooting lens 14a Focusing means 500 AFIC 501 Light emitting element 502 Light receiving element 503 Light emitting lens 504 Light receiving lens 505 Selection driver 601 Light receiving element 602 Light receiving element 603 Light receiving lens 604 Light receiving lens 605 A / D converter 610 Subject

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 7/32 G02B 7/11 N G03B 13/36 A H04N 5/232 B G03B 3/00 A F term ( (Reference) 2F065 AA06 DD04 DD09 EE09 FF09 FF24 FF44 GG01 GG10 GG12 GG21 HH04 JJ02 JJ05 JJ16 JJ25 QQ03 QQ29 QQ36 QQ38 2F112 AA06 AC03 CA02 CA12 DA02 DA21 DA26 FA03 FA07 FA36 FA38 FA03 2H01 BB BB BB BB BB CB CC10 CD23 DA02 DA03 DA05 DA22 5C022 AA13 AB24 AB28 AC00 AC51 AC69

Claims (8)

[Claims] A first light receiving means for receiving an image signal of a subject; a light projecting means for projecting light for distance measurement; The reflected light from the subject of the second light receiving means is reflected in accordance with the second light receiving means comprising a plurality of light receiving surfaces for receiving the reflected signal light of the distance light from the subject and the image signal from the first light receiving means. Selecting means for selecting a light-receiving surface for receiving light. 2. The camera distance measuring apparatus according to claim 1, wherein said selection means detects a color or brightness change point of the image signal from said first light receiving means. 3. The distance measuring apparatus according to claim 1, wherein said first light receiving means is a photographing CCD for recording a digital electronic image. 4. A first light receiving means for receiving an image signal of a subject, a light projecting means for projecting distance measuring light in a plurality of directions, and projecting the distance measuring light to the subject. Receiving means for receiving reflected signal light from the subject; determining means for determining an image signal of the first light receiving means; and at least one of the plurality of light emitting directions according to an output of the determining means. And a selecting means for selecting: a distance measuring device for a camera. 5. An image signal output means for outputting an image signal of a subject, a light projecting means for projecting distance measuring light toward the subject, a subject portion for obtaining a subject distance based on the image signal,
Classification means for classifying a subject into a subject part for which a subject distance is to be determined based on a reflection signal at the time of projecting light from the light projecting means. 6. The image processing apparatus according to claim 1, further comprising determining means for performing distance measurement by switching a distance measuring method for each object portion classified by said classification means, and determining a focus position in accordance with a result of the distance measurement at this time. The distance measuring device for a camera according to claim 5, wherein 7. A light projecting means for projecting distance-measuring light to a subject, an image signal output means for detecting an image signal of the subject, and a light projecting means based on an output from the image signal output means. Selecting means for selecting a distance measuring area to which the distance is to be measured. 8. A camera having a function of performing automatic white balance control, comprising: a light projecting means for projecting a distance measuring light to a subject; a light receiving means for receiving a reflected signal from the subject; A correction means for correcting the output of the light receiving means when controlling the light projecting means in accordance with the brightness to obtain focusing information.