JPH0778572B2 - Camera autofocus device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention is a so-called multi-point distance measuring method in which a photographing distance is obtained based on distance measuring information in a plurality of directions and a photographing lens is set at a focusing position according to the photographing distance. System automatic focus adjustment device.

B. Conventional technology Conventionally, even when the main subject is not located in the center of the shooting screen, it is possible to focus on the main subject without troublesome operations such as focus lock. There is known a camera of a multi-point distance measuring method in which a plurality of distance information is obtained by performing a distance measurement and the photographing distance is set by the following various methods based on the distance information.

A method of selecting the distance information of the closest subject from multiple distance information and setting the shooting distance, weighting the distance information for the subject located in the central area of the shooting field, which corresponds to the shooting screen. Method to determine the average distance and set the shooting distance based on this, a method to control the lens position and aperture value so that the subjects at the closest distance and the farthest distance on the shooting screen are included in the depth of field. .

C. Problems to be Solved by the Invention By the way, focusing on the positional relationship of the subjects existing in the scene, when the shooting location is outdoors such as a park or a tourist spot, the main subject and the rear object are the walls. , Trees, mountains, etc. are often relatively far away, whereas in places such as indoors of ordinary households, the distance between the main subject and surrounding objects such as walls, windows, and figurines is outdoors. Often closer than.
Regarding the distance between the main subject and the photographer, comparing indoors and outdoors, it is often the case that indoor photography is closer than indoor photography.

However, in the conventional multi-point distance measuring method, the photographing distance of the photographing lens is uniformly designed by the methods shown in the above to 1 without distinguishing between indoor and outdoor, and it is not always possible to focus properly. I met the problem of not having it.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic focus adjusting device for a camera, which solves the above-mentioned problems by appropriately changing the shooting distance setting method according to shooting outdoors or indoors.

D. Means for Solving Problems Explaining with reference to FIG. 1, which is a diagram corresponding to claims, according to the present invention, the automatic essential point adjustment of a camera for driving a photographing lens according to a set photographing distance to focus on a subject. Applies to equipment. And the above-mentioned problem is that the distance measuring means 101 for measuring the distance to the subject existing in each of a plurality of regions including the central region in the object field and the peripheral region thereof, and that the shooting location is outdoors. And a shooting location signal output means 102 for outputting an outdoor signal indicating that the subject is indoors, and distance measurement is performed to determine whether the subject located in the central region of the field is the main subject to be focused. When it is determined that the distance of the central region is included in the reference distance range, the photographing distance that sets the photographing distance based on at least the distance measurement value of the central region. The photographing distance setting means 103 includes a reference distance range 103A for outdoor use and a reference distance range 103B for indoor use, and defines the far side of the reference distance range. Distance from when the indoor signal is output It is solved by setting so it is farther in distance when the outdoor signal is output.

E. Action Determines whether or not the subject located in the central area of the scene is the main subject to be focused, and determines that the distance in the central area of the scene is within the standard distance range When done,
The central portion subject is determined to be the main subject, and the photographing distance setting means 103 sets the photographing distance based on at least the distance measurement signal of the central region. This reference distance range consists of an outdoor reference range 103A and an indoor reference range 103B, and at least the long distance side of those reference ranges has different values between indoor shooting and outdoor shooting, that is, It is set to be farther when shooting outdoors. Therefore, when the shooting location signal output means 102 outputs an outdoor signal, the shooting distance is set in a method suitable for an outdoor scene, and when an indoor signal is output, a shooting method is suitable for an indoor scene. The distance is set, and the possibility of focusing becomes higher than before under various conditions.

F. Embodiment One embodiment will be described with reference to FIGS.

In FIG. 2, a light source drive circuit 2, a distance measuring circuit 3, and a photometric circuit 4 are connected to a control circuit 1 including a CPU 1a, ROM 1b, RAM 1c, etc. A light projector 5 is connected to the light source drive circuit 2, and the light projector 5 is operated by a command from the CPU 1a to project a light beam toward a subject. Distance measuring circuit 3
Is, as shown in FIG.
The central area A and two peripheral areas B and C are used to measure a total of three distances. The distance measuring circuit 3 irradiates the subject located in each of the areas A to C from the projector 5. A light receiving element 6 that receives the reflected light of the reflected light is connected. As shown in FIG. 4, the photometric circuit 4 divides the object field 20 into five areas D to E and performs photometry on each area. The elements 7d to 7h are connected.

A lens drive circuit 8 and an exposure control circuit 9 are connected to the control circuit 1 to drive and control the photographing lens 10 and the exposure control member 11, respectively. Here, the exposure control member 11 is composed of a shutter and a diaphragm.

Further, switches SW1 and SW2 are connected to the control circuit 1 in association with the operation of a release button (not shown). Switch S
W1 turns on when the release button is pressed halfway, and switch SW2 turns on when the release button is pressed completely. Control circuit 1
Controls the drive of each circuit by inputting from these switches SW1 and SW2.

The CPU 1a determines whether the shooting location is indoors or outdoors based on the photometric data obtained from the areas D to H of the field, and changes the shooting distance setting method according to the determination result. The determination as to whether it is indoor or outdoor can be made, for example, by the following two methods based on the photometric data from the light receiving elements 7d to 7h corresponding to the above-mentioned divided areas D to H.

Average value of luminance Ev obtained from photometric data of all areas D to H
If Evmean is Ev9 or more, it is determined to be outdoors, and if Evmean is less than Ev9, it is determined to be indoor.

If the brightness of the pair of areas B and C, the brightness of the pair of areas C and E, or the brightness of the pair of areas B and D is high, it is determined outdoors, and if it is not high, it is determined indoors.

It should be noted that the above method and the method may be taken into consideration to make the determination. Alternatively, it may be determined to be outdoor when it is determined to be natural light by measuring the color temperature of the field, and indoor when it is determined to be an indoor illumination lamp such as a fluorescent lamp. This can be easily detected by the color temperature sensor. Furthermore, it may be determined to be outdoors when the point of the multipoint distance measurement indicates infinity.

Next, the procedure from photometric processing to photographing will be described with reference to FIGS. 5 (a) and 5 (b).

When the half-push switch SW1 in FIG. 2 is turned on, first, in step S1, photometric processing is performed. That is, the detection signal from the light receiving element 7d~7h corresponding to five regions D~H the object scene shown in FIG. 4, the luminance of each region at the photometric circuit 4 E _VD to E _VH
Are calculated and stored in the RAM 1c, respectively.

Then, in step S2, distance measurement is performed on each central area A of the subject.
That is, the control circuit 1 operates the light projector 5 via the light source drive circuit 2 to project the light toward the central subject. The reflected light from the central object is received by the light receiving element 6, and its detection signal is input to the distance measuring circuit 3. This detection signal is converted into a voltage by the distance measuring circuit 3, and the converted voltage value is sent to the control circuit 1 and stored in the RAM 1c as the central distance measuring value Lc.

When the central distance measurement value Lc is calculated, it is determined in step S3 whether or not the central object is 5 m or less, and if it is more than 5 m, the process proceeds to step S7 along the flow of No, and the peripheral area of the object field is determined. Area B, C
Distance measurement is performed in the same manner as above, and the peripheral distance measurement value Ls
₁ and the peripheral distance measurement value Ls ₂ are calculated, and the average value of these is stored in the RAM 1c as the peripheral distance measurement value Ls. Next, in step S8, it is determined whether or not the peripheral subject is 5 m or less. If it is 5 m or less, the process proceeds to step S9, the peripheral distance measurement value Ls is selected as the photographing distance L of the photographing lens, and the photographing is performed in step S11. Be seen. When step S8 is denied, that is, when the peripheral subject is farther than 5 m, the central distance measurement value Lc is selected as the shooting distance L in step S10, and step S1
Shooting is done at 1.

On the other hand, if it is determined in step S3 that the central distance measuring value Ls is 5 m or less, the process proceeds to step S4, and it is determined whether the central distance measuring value Lc is 1 m or more. If the distance is less than 1 m, the process proceeds to step S10, and shooting is performed in step S11 with the shooting distance L = Lc.

That is, when the center distance measurement value Lc is less than 1 m,
Shooting is performed by the center distance measurement Lc without performing distance measurement of the peripheral subject existing in the peripheral portion of the shooting screen. In this embodiment, 1 m is set, but it is not limited to 1 m, and any value may be used as long as it is a short distance of a predetermined distance or less.

If the central distance measurement value Lc is determined to be 1 m or more in step S4, the process proceeds to step S5, and the distance measurement of peripheral objects existing on the periphery of the shooting screen is performed in the same manner as in step S7. The average value is stored in the RAM 1c as the peripheral distance measurement value Ls. Then, in step S6, the peripheral distance measurement value Ls
Is less than 5m, if it is determined to be more than 5m,
In step S12, the shooting distance L = Lc is set and step S11
Is taken in.

If it is determined in step S6 that the distance is 5 m or less, that is, if the central distance measurement value Lc and the peripheral distance measurement value Ls are both 5 m or less, in step S13, the shooting location is indoors due to the above-described brightness E _{VD to} E _VH. Determine whether it is outdoors or outdoors. When it is determined in step S13 that the shooting location is indoors, the process proceeds to step S14, and the center distance measurement value L
Determine whether c is within the range of 1m or more and 3m or less. This range of distances is a reference distance range for determining whether or not the subject located in the central area is the main subject to be focused.

If the central distance measurement value Lc is within the range of 1 to 3 m, the process proceeds to step S15, and it is determined whether the positional relationship between the central object and the peripheral object is within 50 cm. If the central subject and the peripheral subject are located within 50 cm, the process proceeds to step S16. In this step S16, the depth of field is deepened by narrowing down the aperture sufficiently within the range where proper exposure is obtained, and whether the central insertion value Lc and the peripheral distance measurement value Ls are included in the depth of field, Alternatively, the center distance measurement value Lc, which is the distance between the center distance measurement value Lc and the peripheral distance measurement value Ls, is set to the shooting distance L included in the depth of field. Then, photographing is performed in step S17. The aperture value set in step S16 is set so that the shutter speed is such that camera shake does not occur. If it is determined in step S15 that the central object and the peripheral object are located more than 50 cm apart, the shooting distance L = Lc is set in step S19 and shooting is performed in step S17.

Further, if the central distance measurement value Lc is not within the range of 1 to 3 m in step S14, the process proceeds to step S18, and in step S18, it is determined whether the peripheral subject is within the range of 1 to 3 m. If the answer is NO, the photographing distance L = Lc is set in step S19 and the photographing is performed in step S17. On the other hand, step S18
If affirmative, the shooting distance L = Ls in step S20.
As a result, shooting is performed in step S17.

Next, when it is determined in step S13 that the shooting location is outdoors, in step S21, the central object is 2 to 4 m.
It is determined whether it is within the range of. This range of distances is a reference distance range for determining whether or not the subject located in the central area is the main subject to be focused. If it is determined to be within the range of 2 to 4 m, the process proceeds to step S22, and it is determined whether or not the positional relationship between the central subject and the peripheral subject is within 1 m. If it is within 1 m, the process proceeds to step S23. move on. In this step S23, the depth of field is deepened by narrowing down the aperture sufficiently within the range where proper exposure is obtained,
The central distance measurement value Lc and the peripheral distance measurement value Ls are included in the depth of field, or the distance between the central distance measurement value Lc and the peripheral distance measurement value Ls The distance value Lc is controlled to the shooting distance L included in the depth of field. Then, photographing is performed in step S17. It should be noted that the aperture value set in step S23 is determined so that the shutter speed is such that camera shake does not occur, as described above. Also step
If it is determined in S22 that the distance between the two object fields is longer than 1 m, the process proceeds to step S24, and shooting is performed in step S17 with the shooting distance L = Lc.

Next, when it is determined in step S21 that the central distance measurement value Lc is not within the range of 2 to 4 m, it is determined in step S25 whether the peripheral distance measurement value Ls is within the range of 2 to 4 m. If the answer is NO, the shooting distance L is set to Lc in step S24 and step S
Shooting is done at 17. If the peripheral distance measurement value Ls is within the range of 2 to 4 m, the photographing distance L = Ls is set in step S20 and the photographing is performed in step S17.

In the above embodiment, the distance measuring circuit 3 operates the distance measuring means 101 by C
PU1a, especially step S13 is the photographing location signal output means 102
Further, the CPU 1a constitutes the photographing distance setting means 103, respectively.

In addition, in step S15 or step S22, the positional relationship between the central subject and the peripheral subject is within 50 cm or
Even when it is determined that the distance is within 1 m, the process may proceed to step S19 or step S24 to set the central distance measurement value Lc as the shooting distance L. Further, although the above-mentioned positional relationship is set to 50 cm or 1 m, it is not limited to 50 cm or 1 m, and any value may be used as long as the central part subject and the peripheral part subject are relatively close. Note that, in this case, the outdoor distance is longer than the indoor distance, but the brightness of the subject is higher and the diaphragm is narrowed down more as the outdoors.

Further, the positional relationship between the central subject and the peripheral subject may be determined as a predetermined distance ratio. In this case as well, the distance ratio outside the room is set to a larger value. Further, the above-mentioned reference ranges for indoors and outdoors are set to 1 to 3 m and 2 to 4 m, but the numerical values are not particularly limited as long as the long distance side of the outdoors is farther than the long distance side of the indoor side.

As described above, according to the processing procedure of steps S14 and S15, or steps S21 and S22, in the case of indoor photography and outdoor photography, respectively, when the central subject is located within the reference distance range, the central subject is selected. Control is performed such that priority is given to focus.

The distance measuring direction (distance point) is not limited to that shown in FIG. As for the distance measurement value used to set the shooting distance L, the central distance measurement value Lc and the peripheral average distance measurement value Ls are used in the above embodiment, but independent information is obtained for each of a plurality of areas. The distance measurement information may be obtained or partially averaged as long as a plurality of pieces of distance measurement information are obtained.

Furthermore, although a case has been described in which the camera automatically determines whether it is outdoors or indoors, an outdoor signal or an indoor signal may be output by a manual switch.

The effects of the above embodiment will be described below.

In the above-mentioned conventional and shooting distance setting methods, there is a high possibility that the tree will be in focus if a tree with a low height is in front of the main subject, such as in an outdoor park, but like the present embodiment. If the central subject is within the range of 2m to 4m, it is determined as the main subject, and if the shooting distance is controlled by the distance measurement information, the person who is the main subject may be in focus in such a case as well. Get higher

Further, in the above conventional method, when there is a person on the other side of the table in the room and flowers are placed on the table, if the depth is increased to include the person and the flowers, the shutter speed becomes slow and the blurring is reduced. There is a high possibility that
In the present embodiment, in the case of indoor shooting, the shooting distance is set in consideration of the depth of field only when the distance between the central object and the peripheral objects is 0.5 m or less, and the central area measurement is performed when the distance is 0.5 m or more. Since the distance value is set as the shooting distance, extreme narrowing down is not performed when the depth of field is taken into consideration, and since the shutter speed is limited to the shutter speed, the conventional camera shake problem is solved.

G. Effect of the Invention According to the present invention, the shooting distance calculation method of the shooting lens is changed depending on whether the shooting location is outdoors or indoors. Therefore, even in a camera that controls the shooting distance by a multipoint distance measurement method,
There is a high possibility that you can take a focused photo regardless of the outdoors.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram. 2 to 5 (a) and 5 (b) are for explaining one embodiment, FIG. 2 is an overall configuration diagram, FIG. 3 is a diagram showing a distance measuring region, and FIG. 4 is a photometric region. 5A and 5B are flowcharts for controlling the shooting distance. 1: Control circuit, 3: Distance measuring circuit 4: Photometric circuit, 10: Shooting lens 101: Distance measuring means 102: Shooting location signal output means 103: Shooting distance setting means

Claims (1)

[Claims] 1. An automatic focusing device for a camera, which drives a photographic lens according to a set photographic distance to focus on a subject, comprising: a plurality of regions including a central region in a field and a peripheral region thereof. Distance measuring means for measuring the distance to the subject respectively present, photographing location signal output means for outputting an outdoor signal indicating that the photographing location is outdoors and an indoor signal indicating that the photographing location is indoors, Whether the subject located in the central region of the scene is the main subject to be focused is determined by the distance of the measured central region, and the distance of the central region is included in the reference distance range. If it is determined that the distance is at least the center distance, the photographing distance setting means for setting the photographing distance based on the distance measurement value of the central area is provided. The standard distance range of Therefore, the distance that defines the far side of these reference distance ranges must be set so that the distance when the outdoor signal is output is longer than when the indoor signal is output. An automatic focus adjustment device for cameras.