JP3238484B2 - Distance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an active type distance measuring device having a function of detecting photographing through glass used in an autofocus camera or the like.

[0002]

2. Description of the Related Art A camera using a conventional multi-point distance measuring method through a glass, for example, an object in a show window,
Or if you want to shoot the scenery behind the window glass,
Incorrect distance measurement of the glass causes the glass to be in focus, and for example, a distant view beyond the glass that the user wanted to take may become a blurred photograph.

Accordingly, the present applicant has filed Japanese Patent Application No. Hei 3-19031.
No. 3 proposes a distance measuring device having a function of detecting photographing through glass that can focus on a subject such as a distant view located on the other side of the desired glass even through the glass.

FIG. 6 schematically shows a distance measuring device having the above-described photographing function through glass, and 1 is an exterior of the distance measuring device,
Reference numeral 2 denotes a light projecting lens, and 3 denotes a light receiving lens. Reference numeral 4 denotes a light projecting element having light emitting elements 4R, 4C, and 4L for the right, center, and left objects in the finder. 5 is a light receiving element,
It is composed of a two-part SPD or PSD semiconductor position detector, and is composed of three light receiving elements 5R, 5C and 5L.

In the multi-point distance measuring apparatus thus configured, each element of the light projecting element 4 is controlled by a control device (not shown) to emit light sequentially, and light reflected on a subject or glass is received by the light receiving element 5. The control device determines whether or not the photographing is performed through the glass.

FIGS. 3A and 3B are diagrams showing a state in which light emitted from the light emitting element 4C is received by the light receiving element 5. FIG. 3A shows a case where a subject is close, and FIG. 3B shows a case where a distant view through glass. ,
(C) shows a case of a display object (short distance) through a show window.

When the object shown in FIG. 3A is at a close distance, the light beam A emitted from the light projecting element 4C is reflected from the object and received by the light receiving element 5L. At this time, the signal N output from the light receiving element 5L is large because the subject distance is short.

In the case of the distant view through the glass shown in FIG. 3B, the light beam A projected from the light projecting element 4C is divided into a light beam B specularly reflected on the glass surface of the glass 8 and a light beam C transmitted through the glass 8. And a weak light beam D diffused due to minute irregularities or dirt on the surface of the glass 8, and only the diffusely reflected light D on the glass surface reaches the light receiving element 5.

FIG. 3C shows a case in which a subject is located close to the glass, for example, when a display object is taken through a show window, the light beam C transmitted through the glass 8 is reflected on the subject, and the light receiving element is detected. It is incident on 5C. Further, the diffusely reflected light beam D also enters the light receiving element 5L.

The operation of the distance measuring apparatus having the function of detecting photographing through glass will be described with reference to the flowchart of FIG.

[Step (hereinafter abbreviated as #) 1] Light-emitting element 4C emits light, projects light toward a subject, and receives light
The output signal level N of L is stored, and the process proceeds to # 2. The stored signal level N is used as data for a close warning to be performed later and distant view through glass.

[# 2] Based on the data of the light receiving element 5R which receives the reflected light by causing the light projecting element 4R to emit light, the right distance in the viewfinder is measured based on the data of the light receiving element 5R, and the distance measurement data R is stored. Then, proceed to # 3.

[# 3] Based on the data of the light receiving element 5L that emits light toward the subject by causing the light emitting element 4L to emit light, distance measurement is performed on the left side in the viewfinder based on data of the light receiving element 5L, and the distance measurement data L is stored. Then, proceed to # 4.

[# 4] Based on the data of the light receiving element 5C that emits light toward the subject by causing the light emitting element 4C to emit light, the distance in the center of the finder is measured based on the data of the light receiving element 5C, and the distance measuring data C is stored. Then, proceed to # 5.

[# 5] A close warning is determined. The magnitude of the signal N stored in # 1 is compared with a threshold value. If the signal N is larger than the threshold value, it is determined that a close warning has been issued. I do. If the signal N is smaller than the threshold, the process proceeds to # 6.

[# 6] Subject determination through the show window is performed. The signal C measured in # 4 is compared with a threshold, and the signal C
Is larger than the threshold value, it is determined that there is a subject over the show window, and the process proceeds to # 10, where the obtained distance measurement data is selected. If the signal C is smaller than the threshold, the process proceeds to # 7.

[# 7] A distant view through glass is determined. # 1
The presence or absence of the signal N measured in the step is determined.
Proceed to 10 and select the obtained distance measurement data. The signal N
If there is, it is determined that it is a distant view through the glass, and the process proceeds to # 9.

[# 9] Since it is determined that the view is a distant view through the glass, the distance measurement data is set to infinity.

[0019]

In the above-described conventional distance measuring apparatus, an erroneous detection through the glass may be caused due to a defect of the light projecting element 4.

The light projecting element 4 has light emitting portions 4R, 4C, and 4L provided on an aluminum electrode portion 4-1 as shown in FIG. 4A, and also has aluminum as shown in FIG. Electrode part 4-
1, a bonding line 4-2 is bonded, and a mask (not shown) is covered on the upper part of the light emitting units 4R, 4C, and 4L.

In the light projecting element 4 having such a configuration, extraordinary light emission in which light directly leaks as shown by oblique lines occurs between the masks, in addition to the light emission from the regular light emitting portion painted black, or FIG. As shown in (b), the projected light was irradiated to the bonding line 4-2, and the reflected light sometimes leaked as irregular light emission.

As shown in FIGS. 5A and 5B, when there is a non-regular light emitting unit 4CC adjacent to the light emitting unit 4C, FIG.
As shown in (a), the light projection E from the light emitting unit 4C is received by the light receiving element 5C, and the light leakage F from the irregular light emitting unit 4CC is received by the light receiving element 5R.

That is, the light receiving elements 5C and 5 of the light receiving element 5
When light is received at R, as described with reference to the flowchart of FIG. 7, since the mode is the through-glass shooting mode, it is erroneously determined to be through-glass shooting even at a normal shooting distance.

An object of the present invention is to solve such a conventional problem and to provide a distance measuring apparatus capable of measuring a desired object without erroneous determination.

[0025]

According to a first aspect of the present invention, there is provided a light projecting means for projecting light in a plurality of light projecting axis directions, and a light projecting means provided for each of the light projecting axes. The distance of the subject in each light-projection axis is determined by the output of each light-receiver provided corresponding to each light-projection axis by the light projection in each light-projection axis. In a distance measuring device for setting a predetermined distance by evaluating an output at a light receiving unit that does not correspond to the light projecting axis when projecting light at a predetermined light projecting axis of the light axes, Compare the output of the light receiving unit corresponding to the light projecting axis and the output of the light receiving unit that does not correspond to the light projecting axis when light is projected on one light projecting axis. A light receiving unit whose output at the light receiving unit corresponding to the light projecting axis when light is projected on two light projecting axes does not correspond to the light projecting axis When it is determined to be greater than the output of the light receiving unit output by the light receiving portion that does not correspond to the light projecting axes be present prohibits setting of the predetermined distance, corresponding to the light projection axis The distance of the subject is obtained by the output of (1). A second configuration for realizing the object of the present invention includes a light projecting means for performing each of the light projecting into a plurality of light projection axis, the light receiving portion provided corresponding to each of the light projecting axes, each projection The distance of the subject in each light-projection axis is determined by the output of the light-receiving unit provided corresponding to each light-projection axis by the light-projection in the light axis, and a predetermined one of the plurality of light-projection axes is projected. Distance measurement that evaluates the output of a light receiving unit that does not correspond to the light projection axis when light is projected on the axis and determines that a light-transmitting object that reflects a part of the light is present in the vicinity In the device, when the light is projected on the predetermined one light projecting axis, the output of the light receiving unit corresponding to the light projecting axis is compared with the output of the light receiving unit not corresponding to the light projecting axis. And the predetermined
When it is determined that the output at the light receiving unit corresponding to the light projecting axis when performing light projection at one light projecting axis is larger than the output at the light receiving unit not corresponding to the light projecting axis, It is characterized in that the determination that a light-transmitting object is present in the vicinity is prohibited even if an output from a light receiving unit that does not correspond to the light projecting axis exists.

[0026]

1 and 2 show an embodiment of a distance measuring apparatus according to the present invention.

The distance measuring apparatus of this embodiment has the same configuration as the active three-point distance measuring method shown in FIG. 6, and the light projecting element 4 has three light emitting parts 4R, 4C, 4L. The light from each of the light emitting units is sequentially projected toward the subject via the light projecting lens 2, and the diffusely reflected light from the subject or the glass is received by the light receiving units 5 R, 5 C, and 5 L of the light receiving element 5.

Reference numeral 6 denotes a distance calculation circuit including a known double integration circuit and the like, to which information from the light receiving element 5 is input.
A control device 7 controls the distance calculation circuit 6 and performs AF drive control and the like based on output information from the distance calculation circuit 6.

FIG. 2 is a flowchart for explaining the operation of this embodiment controlled by the control device 7.

[# 1] The light emitting element 4C emits light and emits light toward the subject, stores the output signal level N of the light receiving element 5L, and proceeds to # 2. The stored signal level N is used as data for a close warning to be performed later and distant view through glass.

[# 2] Based on the data of the light receiving element 5R which receives the reflected light by emitting the light from the light projecting element 4R, the right distance in the finder is measured, and the distance measurement data R is stored. Then, proceed to # 3.

[# 3] Based on the data of the light receiving element 5L that receives the reflected light by emitting the light from the light projecting element 4L and measuring the distance to the left side in the finder, the distance measuring data L is stored. Then, proceed to # 4.

[# 4] Based on the data of the light receiving element 5C which receives the reflected light by emitting the light from the light projecting element 4C, the distance in the center of the viewfinder is measured, and the distance measuring data C is stored. Then, proceed to # 5.

[# 5] A close warning is determined. The magnitude of the signal N stored in # 1 is compared with a threshold value. If the signal N is larger than the threshold value, it is determined that a close warning has been issued. I do. If the signal N is smaller than the threshold, the process proceeds to # 6.

[# 6] Judgment of the subject through the show window is performed. The signal C measured in # 4 is compared with a threshold, and the signal C
Is larger than the threshold value, it is determined that there is a subject over the show window, and the process proceeds to # 10, where the obtained distance measurement data is selected. If the signal C is smaller than the threshold, the process proceeds to # 7.

[# 7] A distant view determination 1 through glass is performed. #
The presence or absence of the signal N measured in step 1 is determined. If there is no signal N, the process proceeds to step # 10, and the obtained distance measurement data is selected. If the signal N is present, it is determined that the view is a distant view through the glass, and the process proceeds to # 8.

That is, in the step # 1, the absence of the signal N means that the light is not leaked to the light projecting element 4 unless it is the distant view through the glass determined here.

However, the presence of signal N means that
In some cases, the signal N is measured due to light leakage. In the conventional case shown in FIG. 7, the presence of the signal N is uniformly determined to be a distant view through the glass. However, in the embodiment of the present invention, in # 8, a distant view through the glass determination 2 for determining whether a distant view through the glass or a leaked light. I do.

[# 8] The distant view judgment 2 through the glass is performed. #
1 and the signal C measured at # 4
And if N ≧ C, it is determined that the subject is a distant view through glass, and the flow proceeds to # 9. When C> N, # 1
Go to 0.

That is, in the case where the light emitted from the light emitting section 4C, which emits light at full power in # 4, is reflected by the object and received by the light receiving element 5C, the output from the light receiving element 5 is very large. In 1, when the light receiving element 5 </ b> L receives light leaked from the light emitting unit 4 </ b> C, the output is small.

Therefore, when C> N, it can be determined that the signal N is a light receiving signal due to light leakage.

On the other hand, if it is over glass Long Distance, the signal N in the # 1 you enter the light receiving element 5R is reflected from the glass surface whereas very large, the light receiving element in the # 4 5
The reflected light from the subject of the light projecting element 4C received at C is small.

Therefore, when N ≧ C, it is determined that the subject is a distant view object through glass.

[# 9] Since it is determined that the view is a distant view through the glass, the distance measurement data is set to infinity.

[0045]

As described above, according to the distance measuring apparatus of the present invention, even if there is light leakage in the light emitting element, the measured distance is selected without selecting the distance for distant view photographing. ,
The problem can be solved without using a costly means such as mechanically taking measures against light leakage on the light emitting element side.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a distance measuring apparatus according to the present invention.

FIG. 2 is a flowchart illustrating the operation of FIG.

FIG. 3 shows a case where the subject is close, and a distant view through glass,
Ray tracing diagram over a show window.

FIG. 4 is an enlarged view of a light emitting element.

FIG. 5 is a diagram illustrating a defect of the light emitting element.

FIG. 6 is a ray tracing diagram of a conventional example.

FIG. 7 is a flowchart illustrating the operation of a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 exterior of distance measuring device 2 light emitting lens 3 light receiving lens 4 light emitting element 5 light receiving element 6 distance calculating means 7 control device 8 glass

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B ^7/ 28-7/32

Claims (2)

(57) [Claims] [Claim 1 further comprising a plurality of the light emitting means, respectively to the light projection axis performs light projection, the light receiving portion provided corresponding to each of the light projecting axes, each by projection of each projection axis The output of each light receiving unit provided corresponding to the light projecting axis determines the distance of the subject in each light projecting axis, and performs light projecting on a predetermined one of the plurality of light projecting axes. A distance measuring device that evaluates an output of a light receiving unit that does not correspond to the light projecting axis and sets a predetermined distance. The output at the light receiving unit corresponding to the axis is compared with the output at the light receiving unit not corresponding to the light emitting axis, and the light emitting axis when the light is emitted at the predetermined one light emitting axis When it is determined that the output of the light receiving unit corresponding to the light emitting axis is larger than the output of the light receiving unit not corresponding to the light emitting axis, Also output in have not received part is be present said predetermined distance
Prohibits setting of the release, the distance measuring apparatus and obtaining the distance of the object by the output of the light receiving unit corresponding to the light projection axis. Wherein a plurality of the light emitting means, respectively to the light projection axis performs light projection, the light receiving portion provided corresponding to each of the light projecting axes, each by projection of each projection axis The distance of the subject in each light-projection axis is determined by the output of the light-receiving unit provided corresponding to the light-projection axis, and a predetermined distance among the plurality of light-projection axes is determined.
When light is projected on one light axis, the output of the light receiving unit that does not correspond to the light axis is evaluated and a light-transmitting object that reflects a part of the light is present in the vicinity. In the distance measuring device to be determined, the output at the light receiving unit corresponding to the light projecting axis when the light is projected at the predetermined one light projecting axis and the output at the light receiving unit not corresponding to the light projecting axis. The output of the light receiving unit corresponding to the light emitting axis when the light is emitted in the predetermined one light emitting axis is compared with the output of the light receiving unit not corresponding to the light emitting axis. When it is determined that the light-transmitting object does not correspond to the light-projecting axis, the determination that the light-transmitting object is present in the vicinity is prohibited. Distance device.