JP3216423B2 - Camera ranging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring apparatus suitable for performing close-up photographing using a passive triangular distance measuring camera having different optical axes in a finder optical system and an autofocus optical system.

[0002]

2. Description of the Related Art Conventionally, as a distance measuring device for a camera, a device using a passive triangular distance measuring method using external light is known. This type of distance measuring apparatus has an autofocus optical system, receives a captured subject image with a pair of line sensors, and performs correlation calculation on pixel data obtained by each of them to obtain distance measuring data. It is configured as
This autofocus optical system is generally provided on a different optical axis from the photographing optical system and the finder optical system.

[0003] In the observation section of the finder optical system, for example, a bracket-shaped ranging frame is written in order to visualize the ranging area, so that the ranging area with respect to the subject is easily viewed. On the other hand, the ranging area where the autofocus optical system actually measures the distance to the subject is displaced with respect to the ranging frame depending on the shooting distance because the optical axis is different from that of the finder optical system. That is, for example, it is assumed that the camera is designed to actually measure the distance to a subject in the distance measurement frame when the shooting distance is 3 m. The luminous flux from the subject that enters the focus optical system is incident from an angle that is more parallel to the optical axis of the finder optical system.
In contrast, when the subject approaches 3 m or less, the luminous flux from the subject incident on the autofocus optical system is changed to the light of the finder optical system when the subject approaches 3 m or less. Since the light is incident from an angle shifted from the axis, the distance measuring area is displaced away from the finder optical system F. As a result, there is a possibility that an inconvenience of performing erroneous distance measurement for a subject different from the photographer's intention may occur.

Therefore, conventionally, a preliminary distance measurement is performed to obtain a temporary distance measurement result, a light receiving range of the line sensor is selected based on the distance measurement result, and the distance measurement is executed again to reduce the influence of parallax. A device that prevents such a problem has been proposed (JP-A-2-293833).

[0005]

In the case of the apparatus described in the above-mentioned publication, there is a problem that the distance measurement requires a long time because of the prior distance measurement. In addition, at the time of re-ranging, only the pixel data of the light receiving range corresponding to the distance measurement result of the pre-ranging is used, so that the light receiving area becomes narrow depending on the shooting distance, and as a result, the correlation value does not exceed the confidence level. ,
There is a problem that a so-called low contrast is obtained and the distance measurement probability is reduced.

The present invention has been made in view of the above, and focuses on the fact that parallax increases with the close-up distance, particularly in the close-up distance. It is an object of the present invention to provide a camera distance measuring device which can prevent a decrease in the distance measuring probability by performing the switching in the case of the photographing.

[0007]

A distance measuring apparatus for a camera according to the present invention comprises a photographing optical system whose focal position is adjusted based on obtained distance measuring data and a finder optical system on which a distance measuring frame is indicated. A pair of line sensors, each receiving a subject image guided from a triangulation-type autofocus optical system having an optical axis different from that of the finder optical system, and capturing pixel data thereof; and a pair of line sensors. Distance measurement means for calculating distance measurement data by executing a distance measurement operation for triangular distance measurement using pixel data from the camera; determining means for determining whether or not the camera is in a close-up shooting mode; Storage means for storing a range of pixel data corresponding to the inside of the ranging frame and a range of pixel data corresponding to the outside of the ranging frame; and determining that the mode is the close-up shooting mode. For the distance measurement means, the first distance data from the pixel data for the range finder frame
Calculation is performed, and pixels outside the distance measurement frame
From the data to perform the calculation of the second distance measurement data, the first
When the distance measurement data cannot be obtained, the arithmetic switching means is adapted to adopt the second distance measurement data.

[0008]

According to the present invention, when the distance to the subject, that is, the photographing distance, changes, the luminous flux from the subject received by the line sensor of the autofocus optical system with respect to the distance measurement frame of the finder optical system (parallel). Lux). In particular, in the close-up shooting mode, the parallax increases. Therefore, it is determined whether the proximity photographing mode, if the close-up mode, with respect to the distance measuring means, the first distance data from the pixel data for the range finder frame
Of the distance measurement frame.
The second distance measurement data is calculated from the raw data. If the first distance measurement data is not reliable because the first distance measurement data is not reliable , the second distance measurement data is calculated . distance data of is employed, the photographing optical system is adjusted focal position in the second distance measurement data.

[0009]

FIG. 1 is a plan view showing an example of an optical system of a camera to which a distance measuring apparatus according to the present invention is applied. A photographing lens 2 constituting a photographing optical system is provided on the front surface (upper side in the figure) of the camera body 1. This taking lens 2 is a zoom lens whose focal length can be changed continuously or in a multipoint manner. A film 3 is arranged behind the photographic lens 2 via an aperture or shutter (not shown) behind the optical axis.

A finder optical system F is interposed between the photographing lens 2 and the film 3 and has a distance of 45 from the optical axis during distance measurement.
The optical axis is branched by an inclined (half) mirror 4 and a finder display unit 5 made of a translucent plate or the like is provided at an image forming position on the rear surface of the camera body 1 via a light deflecting unit such as a prism on the way. It has a configuration in which the subject image is observable through the camera. At a suitable place of the translucent plate constituting the finder display unit 5, for example, at a central position, a required large bracket-shaped ranging frame 50 is provided.
Is marked. The distance measuring frame 50 is for visually guiding the distance measuring area to the subject image displayed on the finder display unit 5. Since the finder optical system F is provided behind the taking lens 2, the finder field magnification changes in conjunction with the change of the focal length of the taking lens 2. In the case where the mirror 4 is of the total reflection type, a well-known configuration is adopted in which the mirror 4 can be retracted from within the optical axis during photographing.

The finder optical system F has a position different from that of the photographing optical system, that is, another optical axis different from the optical axis of the photographing lens 2, and interlocks with a change in the focal length of the photographing lens 2. The same finder function as described above can be realized even if a configuration is employed in which the viewfinder magnification can be changed via an electric interlocking means such as a gear transmission means or a servomotor.

In the embodiment shown in FIG. 1, the autofocus optical system AF is provided in the lateral direction of the photographing lens 2, and includes a pair of objective lenses 61, 62, mirrors 71, 72, 73 and a pair of line sensors 81, 82. Have. This autofocus optical system AF has at least a finder optical system F
Has an optical axis different from the optical axis. The pair of objective lenses 61 and 62 are respectively disposed toward the front at positions separated by a predetermined distance on the front surface of the camera body 1, and a light beam from a subject passing through those objective lenses 61 and 62 is reflected by a mirror 71. , 72 and a mirror 73 to corresponding line sensors 81, 82, respectively.

The line sensors 81 and 82 are arranged in parallel at a predetermined distance from each other, and each is constituted by arranging a large number of light receiving elements such as CCDs in a line. These line sensors 81 and 82 include an objective lens 61,
The subject image that has passed through 62 is received, converted into digital pixel data, and guided to a control unit 9 that executes distance measurement calculation processing and the like. Reference numeral 10 denotes a motor as driving means for driving the photographing lens 2 to a focusing position based on the distance measurement data obtained as a result of the calculation by the control unit 9.

FIG. 2 is a block diagram for explaining a control system of a camera to which the present invention is applied. The control unit 9 has a CPU (Central Processing Unit) 91, a ROM 92, a RAM 93 and the like, and controls the entire operation of the camera in addition to the distance measurement calculation processing. The ROM 92 stores in advance a program for distance measurement calculation processing, a program for general camera operation, a table relating to a predetermined distance measurement range described later, and the like. R
The AM 93 is for temporarily saving the data in the middle of the arithmetic processing.

A switch S1 is a photographing preparation switch for instructing distance measurement and exposure processing, and a switch S2 is a release switch for instructing photographing. Both switches instruct a photographing preparation operation when pressed halfway, and a release instruction when fully pressed. It is preferable to adopt a button type of the type in which the operation is performed.

The motor 10 receives a drive signal from the lens control circuit 11 and adjusts the extension of the taking lens 2. The extension is monitored by an encoder 12. The encoder 12 detects a feeding amount by reading, for example, a bit mark member coded with position information and information of each bit of the bit mark member, which are disposed on the stationary side and the rotating side of the photographing lens 2 facing each other. Thus, the photographing lens 2 can be set to the in-focus position during distance measurement.

The switch S3 is a zoom switch whose focal length is changed between the telephoto side and the wide-angle side in accordance with the operation direction. Numeral 14 denotes a focal length control means which outputs a drive signal to the motor 13 in the operation direction of the switch S3 for an operation time.
To change the focal length. The motor 13 can also be used as the motor 10 if a gear and a clutch are used. The encoder 15 includes a bit mark member and a reading member similar to those of the encoder 12, and is arranged to face the zoom lens in the photographing lens 2 on the stationary side, and outputs code data according to the focal length. The photographing lens 2 has a macro area outside of the wide-angle for enabling close-up photographing, and it is possible to detect whether it is in the macro area by the position data from the encoder 15. ing. The switch S4 is a mode switch for instructing switching between normal shooting and shooting in the macro area.

Reference numeral 16 denotes a luminance detecting circuit for performing exposure detection when the photographing preparation switch S1 is turned on, and an aperture value and a shutter speed are set according to the detection result.

FIGS. 3 and 4 are diagrams for explaining a method of calculating a correlation when obtaining distance measurement data. FIG. 3 (a), FIG.
FIG. 3A shows a one-side shift system, and FIGS.
(B) shows a double-sided shift method.

As shown in FIG. 4, in this example, the objective lenses 61 and 62 of the autofocus optical system AF are arranged in parallel to the right side of the lens of the finder optical system F (the photographing lens 2 in this embodiment). Then, as shown in FIGS. 3 and 4, the line sensor 81 on the side closer to the photographing lens 2 is used as a reference portion, and the line sensor 82 is used as a reference portion. It is assumed that the center of the distance measurement frame of the finder optical system F and the center of the distance measurement area of the autofocus optical system AF coincide with each other with respect to the subject distance of 3 m (Do in FIG. 4).

In the case of the one-side shift, for convenience of explanation, it is assumed that the line sensor 81 of the reference section is constituted by light receiving elements A1 to A4, and the line sensor 82 of the reference section is constituted by light receiving elements B1 to B8. For a two-sided shift,
For convenience of description, the line sensor 81 of the reference unit is a light receiving element A
1 to A6, and the line sensor 82 of the reference unit is assumed to be composed of the same number of light receiving elements B1 to B6.

First, the case of one-side shift will be described. The selection of the light receiving element of the line sensor 81 is fixed, while the light receiving element for outputting the pixel data used for the correlation calculation is provided for the line sensor 82. They are sequentially shifted and selected. That is, the pixel data of the light receiving element Al to A4, first, the pixel data of the light receiving element B1~B4 correlation calculation is selected is executed (corresponding to the shift S ₀ in FIG. 4 (a)), further successively, The pixel data of the light receiving elements B2 to B5 correspond to the pixel data of the light receiving elements A1 to A4 (FIG. 4A).
Equivalent to the shift S _1), the pixel data of the light receiving element B3~B6 the pixel data of the light receiving element A1~A4 (Figure 4
Corresponding to the shift S ₂ of (a)), the pixel data of the light receiving element B4~B7 the pixel data of the light receiving element A1~A4 is equivalent to the shift S ₃ of (FIG. 4 (a)), and finally, the light-receiving The light receiving elements B5 to B5 correspond to the pixel data of the elements A1 to A4.
The pixel data of B8 is (corresponding to shift _SN in FIG. 4A)
The selected correlation calculation is performed. And
A known method is adopted in which the data at the highest correlation value is used as the distance measurement data on condition that the result of each correlation operation exceeds a predetermined threshold value. The predetermined threshold is set in order to determine whether or not the measurement result is reliable. If the measurement result is equal to or smaller than the threshold, it is determined that the distance measurement data has not been obtained.

Next, the case of double-side shift will be described. The light receiving elements of the line sensors 81 and 82 are sequentially shifted and selected. That is, first, the pixel data of the light receiving elements A3 to A6 and the pixel data of the light receiving elements B1 to B4 are selected (corresponding to the shift S ₀ ′ in FIG. 4B), and the correlation operation is executed. and pixel data elements A3~A6 and pixel data of the light receiving element B2~B5 is (corresponding to the shift S ₁ 'in FIG. 4 (b)), the light receiving element B2~B5 the pixel data of the light receiving element A2~A5 Pixel data (see FIG. 4)
(Corresponding to the shift S ₂ ′ in FIG. 4B), the pixel data of the light receiving elements B _{3 to} B 6 correspond to the pixel data of the light receiving elements A 2 to A 5 (corresponding to the shift S ₃ ′ in FIG. 4B), and finally Then, the pixel data of the light receiving elements A1 to A4 and the pixel data of the light receiving elements B3 to B6 are selected (corresponding to the shift _SN 'in FIG. 4B), and the correlation operation is executed. Then, as a result of each correlation operation, data when the correlation value is the highest is set as distance measurement data.

Here, in FIG. 4, in the case of one-side shift, the axis connecting the subject and the center of the distance measurement area is the distance Do.
Center axis of distance measuring frame and principal point A1 of objective lens 61
And a line segment DoA1 connecting. Accordingly, the deviation between the centers of the distance measurement frame in a close enough position than the point Do distance D _N between the ranging area (parallax) is Px.

On the other hand, in the case of both-side shift, the axis connecting the object and the center of the distance measurement area is the center axis of the distance measurement frame at the distance Do and the middle point between the principal points A1 'and A2' of the objective lenses 61 and 62. It becomes a line segment DoAc connecting Ac. Accordingly, the parallax at close distance D _N becomes Px '.

Since Px <Px 'is sufficiently satisfied in the close distance region than the distance Do, if the correlation calculation is performed the same number of times, the one-sided shift produces smaller parallax and more accurate distance measurement data. You can get it.

FIGS. 5 to 8 illustrate the distance measuring operation in consideration of the parallax between the distance measuring frame and the distance measuring area according to the photographing distance. 5A and 5B are diagrams showing a parallax relationship between the distance measurement frame 50 and the distance measurement area 80 according to the photographing distance. FIG. 5A shows a case where the photographing distance is infinite, and FIG.
Shows a case where the shooting distance is 3 m, (c) shows a case where the shooting distance is 1 m, and (d) shows a case where the shooting distance is 0.5 m.

As shown in FIG. 1, the optical axis of the autofocus optical system AF is separated from the optical axis of the finder optical system F.
In the example of FIG. 1, the optical axis of the autofocus optical system AF is set to the right of the optical axis of the finder optical system F, and the line sensor 81 is located on the side closer to the optical axis of the finder optical system F. A line sensor 82 is provided on the right side.

Here, FIGS. 5A to 5D will be described. Now, a subject is located 3 m in front of the camera body 1, and a light beam from this subject and its surroundings is
Let us consider a case where the light is guided to the line sensor 81 after passing through the line sensor 81. Then, of the luminous flux from the subject, the line sensor 81
It is assumed that the range in which the light is received by the distance measuring area 80 is designed in advance so that the distance measuring area 80 and the distance measuring frame 50 coincide with each other at a shooting distance of 3 m. That is, when the subject is at a distance of 3 m as shown in FIG. 2B, the distance measurement frame 50, which is the position where the photographer intends to measure the distance, with respect to the subject shown in the viewfinder display unit 5, and the camera. The distance measurement area 80 where distance measurement is actually performed coincides.

By the way, as shown in FIG. 3A, a light beam passing through the objective lens 61 from an object at a distance of 3 m or more is incident on the optical axis of the objective lens 61 at a more parallel angle. Is displaced to the left on the line sensor 81, that is, the side closer to the finder optical system F.

On the other hand, as shown in FIG. 3C, a light beam passing through the objective lens 61 from a subject at a position 1 m is incident on the optical axis of the objective lens 61 at a more shifted angle. The subject image is displaced to the right on the line sensor 81, that is, to the side away from the finder optical system F. Further, as shown in FIG. 4D, a light beam passing through the objective lens 61 from a subject at a close distance of 0.5 m is incident on the optical axis of the objective lens 61 at a further shifted angle. The subject image at the shortest distance is further displaced to the right on the line sensor 81, so that approximately half of the subject image deviates from the distance measurement frame.

FIG. 6 is a diagram showing the relationship between the structure of the line sensor and the distance measurement range. The structure of the line sensors 81 and 82 applied to the present invention can be applied to either the one-side shift method or the two-side shift method shown in FIGS.
In the one-side shift system, the number of light-receiving elements of the line sensor 82 is provided, for example, twice as many as the number of light-receiving elements of the line sensor 81; The number of elements is set to be the same.

For convenience of explanation, the line sensor shown in FIG. A to G are line sensors 8
1 shows points obtained by equally dividing 6 in the length direction, and AF1-A
F6 indicates a distance measurement range used when obtaining distance measurement data. The G side is a side close to the finder optical system F. AF1 uses light receiving elements in the range of A to C,
F2 uses a light receiving element in the range of B to D, and AF3 uses C
A light-receiving element in the range from D to F is used for AF4, a light-receiving element in the range from E to G is used for AF5, and a light-receiving element in the range from A to G is used for AF6, An element is used. At a close distance where the shooting distance is shorter than 0.5 m, the distance measurement range AF4, A
It can be seen that F5 is off.

The control unit 9 determines the distance measurement ranges AF1 to AF
Distance measurement data is obtained for each of the six types. In FIG. 6, the range where the shooting distance is 1 m to infinity is the normal shooting mode, and the close range of 0.5 m to 1 m is classified as the macro mode. The normal shooting mode and the macro mode are separated by one shooting lens 2. The switching can be set, and the control unit 9 identifies which mode is set based on the detection data from the encoder 15 or from the state of the mode switch S4. When the control unit 9 is set to the macro mode,
Distance measurement ranges AF1 to AF3 are set within the distance measurement frame, and distance measurement ranges AF4, AF5, and AF6 are set outside the distance measurement frame. The correspondence between the inside and outside of the distance measurement frame and each distance measurement range is stored in the ROM 92. It should be noted that whether or not the area is a macro area can be identified by the encoder 12 instead of the encoder 15 depending on the type of the photographing lens.

Next, the operation of calculating the distance measurement data will be described with reference to the flowchart of FIG. When the switch S1 is turned on, the distance measurement process is started and the objective lenses 61 and 6 are started.
The luminous flux of the subject passing through 2 is received by all the light receiving elements of the line sensors 81 and 82, converted into a digital value, and taken into the control unit 9 (# 2).

Correlation processing is performed between the line sensor 81 and the line sensor 82 for each of the distance measurement ranges AF1 to AF6 based on the taken pixel data from all the light receiving elements.
Each distance measurement data is calculated (# 4). Here, it is determined whether or not the photographing lens 2 is set to the macro mode (# 6). If the photographing lens 2 is not in the macro mode, since the normal mode is set, the normal distance measurement process "normal photographing"(# 8) is executed. Then, this flow ends. On the other hand, in the macro mode, it is determined whether or not the distance measurement data has been obtained in the distance measurement ranges AF1 to AF5 (# 10). AF area AF1-AF
If the distance measurement data is obtained in step 5, it is further determined whether or not the distance measurement data is obtained in the distance measurement frame, that is, in the distance measurement ranges AF1 to AF3 (# 12). If the distance measurement data is obtained in the distance measurement ranges AF1 to AF3,
It is determined whether or not the distance measurement data is equal to or less than a predetermined value, for example, 1 m (# 14). If the distance measurement data is equal to or less than the predetermined value, the latest value is selected as the distance measurement data (# 16). To end.

If NO in steps # 12 and # 14, it is then determined whether or not distance measurement data has been obtained outside the distance measurement frame, that is, in the distance measurement ranges AF4 and AF5 (# 1).
8). If the distance measurement data is obtained in the distance measurement ranges AF4 and AF5, it is determined whether or not the distance measurement data is a predetermined value, for example, 1 m or less (# 20). Select the latest value as the distance measurement data (# 2
2), end this flow. Also, N in # 18 and # 20
If it is O, a specific value, for example, 0.6 m is set as distance measurement impossible (# 24), and this flow ends.

On the other hand, in # 10, the distance measurement ranges AF1 to AF5
If no distance measurement data was obtained in
It is determined in Step 6 whether or not the distance measurement data has been obtained (# 2).
6) If no distance measurement data has been obtained even in the distance measurement range AF6, the process proceeds to # 24, where a predetermined value of 0.6 m is set.
On the other hand, if the distance measurement data has been obtained in the distance measurement range AF6, it is determined whether or not the distance measurement data is equal to or less than a predetermined value 1m (# 28). The data is adopted (# 30), and this flow ends.

FIG. 8 is a flowchart showing a subroutine of "normal processing" of # 8. In normal processing, first,
It is determined whether or not the distance measurement data has been obtained in the distance measurement ranges AF1 to AF5 (# 40). If the distance measurement data has been obtained, the latest value is selected as the distance measurement data (# 4).
2) Return. On the other hand, if the distance measurement data has not been obtained, it is determined whether or not the distance measurement data has been obtained in the distance measurement range AF6 (# 44). Distance measurement data is adopted (#
46) Conversely, if the distance measurement data has not been obtained, a specific value, for example, 0.6 m is set as distance measurement impossible (# 4).
8) Return.

As described above, in accordance with the detected focus position, the distance measurement data is obtained in the distance measurement range in the distance measurement frame, the focus position is adjusted using the distance measurement data, and the distance measurement data is not valid. At this time, since the distance measurement data in the distance measurement range outside the distance measurement frame is adopted, the occurrence of distance measurement failure is further reduced.

FIGS. 9 to 11 illustrate the distance measuring operation for the distance measuring frame 50 in consideration of the enlargement and reduction of the distance measuring area 80 according to the focal length of the photographing lens 2. FIG.

FIG. 9 is a diagram showing the relationship between the scaling of the ranging area 80 according to the focal length with respect to the ranging frame 50.
(A) when the focal length f = 35 mm, (b) when the focal length f = 70 mm, (c) when the focal length f = 105 m
m.

With respect to the distance measuring frame 50, the distance measuring area 80
The reason why changes in scale is as follows. In the finder optical system F, the finder field magnification changes in accordance with the focal length f of the photographing lens 2, that is, the image magnification, while the magnification of the autofocus optical system AF is fixed. In this case, the distance measurement area 80 is fixed irrespective of the viewfinder magnification, and the distance measurement is performed for a specific position of the subject. On the other hand, the subject shown in the finder display unit 5 is enlarged or reduced in accordance with the finder magnification, so that the range of the subject that fits within the frame of the distance measurement frame 50 differs depending on the finder field magnification.

FIG. 9A shows the distance measuring frame 5.
Since the size of 0 and the size of the distance measurement area 80 match, and in this state, the actual distance measurement data of the camera is obtained in the distance measurement frame 50, it matches the distance measurement position intended by the photographer. . However, as shown in FIG. 5B and further as shown in FIG. 5C, as the finder magnification increases, the subject shown on the finder display unit 5 (and the distance measurement area 80) is also enlarged. Of the distance measuring area 80, which is shifted from the distance measuring area 80 in which the distance is actually measured.

FIG. 10 is a diagram showing the relationship between the structure of the line sensor and the distance measurement range. The structure of the line sensors 81 and 82 applied to the present invention can be applied to either the one-side shift system or the two-side shift system shown in FIGS. The number of light receiving elements is, for example, twice as large as the number of light receiving elements of the line sensor 81. In the double-sided shift method, the number of light receiving elements of both line sensors 81 and 82 is set to be the same.

For convenience of explanation, the line sensor shown in FIG. A to G indicate points obtained by dividing the line sensor 81 into six equal parts in its length direction.
AF6 indicates a distance measurement range used when obtaining distance measurement data. The G side is a side close to the finder optical system F. AF1 uses light receiving elements in the range of A to C,
AF2 uses a light receiving element in a range of BD, AF3 uses a light receiving element in a range of CE, AF4 uses a light receiving element in a range of DF, and AF5 uses a light receiving element in a range of EG. A light receiving element is used, and AF6 uses a range of A to G, that is, all light receiving elements. The focal length of the taking lens 2 is 10
At 5 mm, the distance measurement ranges AF1 and AF5 are
You can see that it is out of the range.

Then, the control unit 9 determines the distance measurement ranges AF1 to AF
Distance measurement data is obtained for each of the six types. In FIG. 10, the photographing lens 2 has a focal length that can be changed within a range of at least 35 mm to 105 mm, and the control unit 9 uses a table previously stored in the ROM 92 based on detection data from the encoder 15. That is, using Table 1, it is determined which focal length range is located, and the ranging range corresponding to the corresponding focal length range is set as inside or outside the ranging frame.

[0048]

[Table 1]

That is, the focal length f is 35 mm to 55 m
In the range of m, the distance measurement frame and the distance measurement area substantially match as shown in FIG.
Is set to be within the distance measurement frame. Focal length f is 56
In the range of mm to 85 mm, as shown in FIG. 10, a part of the distance measurement ranges AF1 and AF5 partially protrude from the distance measurement frame 50, so that the distance measurement ranges AF2 to AF4 are included in the distance measurement frame. The distance ranges AF1 and AF5 are set outside the distance measurement frame. Further, the focal length f is 86 mm to 1
In the range of 05 mm, as shown in FIG. 10, a part of the distance measurement ranges AF2 and AF4 also partially protrude from the distance measurement frame 50, so that the distance measurement range AF3 is within the distance measurement frame and the distance measurement range AF1 is set. , AF2, AF4, and AF5 are set outside the distance measurement frame.

Next, using the flowchart of FIG.
The calculation operation of the distance measurement data will be described. Switch S1
Is turned on, the distance measurement process is started and the objective lens 61,
The luminous flux of the subject that has passed through the line sensors 81 and 82
Are received by all the light receiving elements, and are converted into digital values and taken into the control section 9 (# 60).

Correlation processing is executed between the line sensor 81 and the line sensor 82 for each of the distance measurement ranges AF1 to AF6 based on the taken pixel data from all the light receiving elements.
Each distance measurement data is calculated (# 62). Here, the focal length of the photographic lens 2 is read from the encoder 15 (##
64) Then, based on Table 1, it is determined whether or not the distance measurement range corresponding to the focal length, that is, whether or not the distance measurement data has been obtained within the distance measurement frame (# 66), and the distance measurement data has been obtained. If there is, the latest value is selected as the distance measurement data (# 68), and this flow ends.

On the other hand, if no ranging data has been obtained within the ranging frame, it is subsequently determined whether or not ranging data has been obtained outside the ranging frame, that is, in another ranging range (# 70). ), If distance measurement data has been obtained, the latest value is selected as distance measurement data (# 7).
2), end this flow.

Further, if no ranging data is obtained outside the ranging frame, it is determined whether or not ranging data is obtained in the ranging area AF6 (# 74). Is adopted as distance measurement data (# 76). If not obtained, a specific value, for example, 10
m is set (# 78), and the routine returns.

As described above, in accordance with the detected focal length, the distance measurement data is obtained in the distance measurement range in the distance measurement frame, the focal position is adjusted using the distance measurement data, and the distance measurement data is not valid. At this time, since the distance measurement data in the distance measurement range outside the distance measurement frame is adopted, the occurrence of distance measurement failure is further reduced.

[0055]

According to the present invention, in the close-up shooting mode, the first distance measurement data is obtained from the pixel data in the distance measurement frame.
Of the distance measurement frame.
The second distance measurement data is calculated from the raw data, and the first distance measurement data is calculated.
When the distance measurement data cannot be obtained, the second distance measurement data is adopted, so that the distance measurement probability can be maintained at a high level even in the close-up shooting mode having a large parallax.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an optical system of a camera to which a distance measuring apparatus according to the present invention is applied.

FIG. 2 is a block diagram illustrating a control system of a camera to which the present invention is applied.

3A and 3B are diagrams for explaining a method of correlation calculation when obtaining distance measurement data. FIG. 3A shows a one-side shift method, and FIG.
Indicates a two-sided shift method.

4A and 4B are diagrams for explaining a correlation calculation method when obtaining distance measurement data. FIG. 4A shows a one-side shift method, and FIG.
Indicates a two-sided shift method.

5A and 5B are diagrams illustrating a parallax relationship between a ranging frame and a ranging area according to a shooting distance, wherein FIG. 5A illustrates a case where the shooting distance is infinite, FIG. 5B illustrates a case where the shooting distance is 3 m, (C)
Indicates that the shooting distance is 1 m, and (d) indicates that the shooting distance is 0.5 m.
Is the case.

FIG. 6 is a diagram showing a relationship between the structure of a line sensor and a distance measurement range.

FIG. 7 is a flowchart illustrating an operation of calculating distance measurement data.

FIG. 8 is a flowchart showing a subroutine of “normal processing”.

FIGS. 9A and 9B are diagrams showing a scaling relationship between a distance measurement frame and a distance measurement area according to a focal length, wherein FIG.
In the case of 35 mm, (b) shows the case where the focal length f = 70 mm, and (c) shows the case where the focal length f = 105 mm.

FIG. 10 is a diagram showing a relationship between the structure of a line sensor and a distance measurement range.

FIG. 11 is a flowchart illustrating an operation of calculating distance measurement data.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera main body 2 Photographing lens 3 Film 4 Mirror 5 Viewfinder display unit 50 Distance measuring frame 61, 62 Objective lens 71, 72, 73 Mirror 80 Distance measuring area 81, 82 Line sensor F Finder optical system AF autofocus optical system 9 Control unit 91 CPU 92 ROM 10, 13 Motor 11 Lens control circuit 12, 15 Encoder 14 Focal length control circuit S1 Shooting preparation switch S2 Release switch S3 Zoom switch S4 Mode switch AF1 to AF6 Distance measurement range A1 to A6, B1 to B8 Light receiving element

Continuation of the front page (56) References JP-A-2-293833 (JP, A) JP-A-2-163715 (JP, A) JP-A-60-183879 (JP, A) JP-A-63-26611 (JP) JP-A-62-267713 (JP, A) JP-A-4-92578 (JP, A) JP-A-5-5833 (JP, A) JP-A-2-199436 (JP, A) 7-281085 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B ^7/ 28-7/34

Claims (1)

(57) [Claims] 1. A camera having a photographic optical system whose focal position is adjusted based on obtained distance measurement data and a finder optical system in which a distance measurement frame is indicated, has an optical axis different from that of the finder optical system. A pair of line sensors that receive the subject image guided from the triangulation-type autofocus optical system and take in the pixel data respectively, and distance measurement for triangulation using pixel data from the pair of line sensors Distance measurement means for calculating distance measurement data by performing an operation; determination means for determining whether or not the camera is in a close-up shooting mode; and a range of pixel data corresponding to the distance measurement frame and the distance measurement in the close-up shooting mode A storage unit for storing a range of pixel data corresponding to the outside of the frame; and a distance measurement unit for determining whether the mode is the close-up shooting mode. From the pixel data to the first ranging data
Calculation is performed, and pixels outside the distance measurement frame
From the data to perform the calculation of the second distance measurement data, the first
And a calculation switching means for employing the second distance measurement data when the distance measurement data cannot be obtained .