JP3461399B2 - 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 device for a camera which obtains the distance to an object to be measured by a triangulation method.

[0002]

2. Description of the Related Art Conventionally, in a camera or the like, a light projecting unit for irradiating a light beam toward an object to be measured, and a light projecting unit disposed on the side of the light projecting unit and reflected by the object to be measured. A distance measuring device is used which is composed of a light receiving unit for receiving a light beam, and obtains a distance to an object to be measured by a triangulation method based on an output of the light receiving unit.

By the way, in a distance measuring apparatus adopting such a triangulation method, as shown in FIG. 7A, an infrared light emitting element 12 is used to transmit an object to be measured via a light projecting lens 11. The light beam is emitted toward the object 15, and the light beam reflected by the object 15 to be measured is received by the light receiving element 14 via the light receiving lens 13, and the object 15 to be measured is output by the light receiving element 14. The distance L is calculated.

Then, when the spot 16 of the light beam as shown in FIGS. 7B and 7C has a spot defect, the spot 17 of the light beam on the light receiving element 14 is condensed.
Is as shown in FIGS. 8 (b) and 8 (c). Comparing this with the case shown in FIGS. 7A and 8A where there is no spot defect, it is found that the positions of the centers of gravity 18 of the focused spots 17 of the light beam on the light receiving element 14 are different from each other. I understand.

Therefore, the distance L to the object 15 to be measured is to be accurately measured in FIG.
In the case as shown in FIG. 8A, when a spot defect occurs, the distance measurement becomes erroneous. As described above, the conventional distance measuring device has a problem that the distance is theoretically erroneously measured due to the lack of the spot.

In view of this problem, various techniques have been proposed for reducing the effect of the spot chipping. For example, in Japanese Examined Patent Publication No. 59-762, a light projecting means for irradiating an object to be measured with a light beam, a light receiving means for receiving a light beam reflected by the object to be measured, and a light projecting means. It is characterized in that two light emitting means are arranged laterally,
A technique related to a distance measuring device capable of measuring a distance without being affected by a spot defect by the outputs of two light receiving means is disclosed.

Further, in Japanese Unexamined Patent Publication No. 64-84211, a light projecting means for irradiating an object to be measured with a light beam and a light receiving means for receiving the light beam reflected by the object to be measured. The light projecting means and the light receiving means are integrated, and have a structure capable of rotating along a predetermined axis, and a spot defect is generated based on the output of the light receiving means when the light receiving intensity of the light receiving means reaches the maximum. A technique related to a distance measuring device that reduces the influence as much as possible is disclosed.

Further, in Japanese Patent Laid-Open No. 4-50610,
At least three light emitting portions are provided, and addition operation and ratio operation are performed on the light emission in the central portion, and the spot deviation is judged from the difference, and the IRED which does not cause the spot deviation from this judgment result.
Since the light is emitted to measure the distance, there is disclosed a technique relating to distance information output means for preventing erroneous distance measurement even if there is a spot deviation in the active distance measurement method.

[0009]

However, although the above-mentioned prior art is effective against spot defects, the conventional distance measuring device is complicated and expensive, and the influence of spot defects is simple and inexpensive. It was not a way to reduce it.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a simple and inexpensive camera which performs correction so as to reduce the influence of spot spots of a light beam and prevents erroneous distance measurement. It is to provide a distance measuring device.

[0011]

In order to achieve the above object, a distance measuring device for a camera according to a first aspect of the present invention comprises a light projecting means for projecting a spot light beam toward a subject and the spot light beam. Receives the reflected light flux from the subject ,
A first signal corresponding to the incident position of the reflected light flux and the reflection
Light receiver that outputs the second signal corresponding to the incident intensity of the light flux
The first distance information based on the first signal and the first distance information;
Distance information for calculating second distance information based on the second signal
Computing means, the first distance information and the second distance information
And the comparison and determination means for comparing the
According to the comparison and determination result of the comparison and determination means, the first distance
Selection means for selecting the separation information or the second distance information,
Based on the distance information selected by the selecting means,
And a subject distance determining means for determining a distance to the subject . The power according to the second aspect is
The comparison and determination means of the camera distance measuring device is
The value of the second distance information within the predetermined area including the value of the separation information
Is characterized by making a determination as to whether or not
It The distance measuring device for the camera according to the third aspect is
In the predetermined area, the value of the first distance information is set to the short distance side and
It is a special feature that it is a region where a certain amount is added to the long distance side.
To collect.

A distance measuring device for a camera according to the fourth aspect.
The device is placed in the predetermined area by the comparison determination means.
If the second distance information is included, spot missing
It is determined that the second distance is not present in the predetermined area.
If the separation information is not included, spot missing will occur
Further, a spot missing determination means for determining that there is
And are characterized. Then, the camera measurement according to the fifth aspect is performed.
In the distance device, the selection means is operated by the comparison determination means.
It is determined that the value of the second distance information is included in the predetermined area.
If selected, select the first distance information above
Is characterized by. Then, the distance measurement of the camera according to the sixth aspect
In the apparatus, the subject distance determining means is the selecting means.
If the first distance information above is selected,
The distance to the subject without correcting the distance information
Characterize.

A distance measuring device for a camera according to the seventh aspect
The selection means is the above-mentioned
If the value of the second distance information is not included in the constant area
If determined, the second distance information above can be selected.
And are characterized. Then, the camera measurement according to the eighth aspect
The distance device is such that the subject distance determining means is equivalent to the selecting means.
If the second distance information is selected, the second distance information is selected.
For the distance information of 2
It is characterized in that the subject distance is corrected. Furthermore
In the distance measuring device for a camera according to the ninth aspect,
Is that the amount of correction differs depending on the distance to the subject
Is characterized by.

[0014]

That is, in the distance measuring device for a camera according to the first aspect of the present invention, the light beam projecting means projects the spot light beam toward the object, and the light receiving means projects the spot light beam.
The reflected light beam from the subject is received and the incident position of the reflected light beam
The first signal corresponding to the position and the incident intensity of the reflected light flux.
The corresponding second signal is output, and the second signal is output by the calculating means.
The first distance information based on the first signal and the second signal
The second distance information based on the calculated distance information is calculated by the comparison and determination means.
The first distance information and the second distance information are compared.
The relationship between the two is judged, and the comparison judgment
The first distance information or the first distance information according to the comparison determination result of the determining means.
The second distance information is selected, and the object distance determining means is selected.
Based on the distance information selected by the selecting means
The distance to the subject is determined . And the second state
In the camera distance measuring device according to
The second area is included in a predetermined area including the value of the first distance information.
It is determined whether or not the value of the distance information is included.
In the distance measuring device for a camera according to the third aspect,
In the predetermined area, the value of the first distance information is set to the near side and the far side.
It is an area in which a certain amount is added to the distance side.

A distance measuring device for a camera according to the fourth aspect.
In this case, the above-mentioned comparison judgment is made by the spot missing judgment means.
The second distance information is included in the predetermined area by means.
If it is rare, it is determined that the spot is not missing.
And the second distance information is included in the predetermined area.
If not, it is determined that the spot is missing.
It Then, in the camera distance measuring device according to the fifth aspect,
The selection means is configured to select the predetermined area by the comparison determination means.
If it is determined that the value of the second distance information is included in
If it is the case, the first distance information is selected. And the sixth
In the range finder of the camera according to the above aspect,
The determining means selects the first distance information by the selecting means.
If selected, correct the first distance information above
Rather than subject distance.

A distance measuring device for a camera according to the seventh aspect.
In the arrangement, the selecting means is
The value of the second distance information is not included in the predetermined area
If it is determined that the second distance information is selected
It The distance measuring device for a camera according to the eighth aspect is
The subject distance determining means is the second means by the selecting means.
If the distance information is selected, the second distance information
For the
Let the distance be the body. Furthermore, the measurement of the camera according to the ninth aspect
In the rangefinder, the above correction is performed according to the distance to the subject.
The correction amount of is different.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. First, the configuration of a distance measuring device for a camera of the present invention is shown in FIG. 1 and will be described. In the figure, signals of switches (not shown) are input to the CPU 1, and the CPU 1 controls the entire sequence of the camera based on a built-in program. An interface IC (hereinafter abbreviated as IFIC) 2 connected to the CPU 1 via a bus line 5 has a light spot light projecting unit 3 and a light spot light receiving unit 4 for receiving light spot reflected light from a subject. It is electrically connected. The light spot light projecting unit 3 and the light spot light receiving unit 4 are driven via the IFIC 2 based on a control signal from the CPU 1.

There are two types of distance measurement information from the light spot light receiving section 4, that is, a first signal corresponding to the position of the light spot and a second signal corresponding to the light receiving intensity of the light spot. Are stored as electric charges in capacitors (not shown) attached to the. When the CPU 1 reads the first and second signals, the CPU 1 sends a data read control signal to the IFIC 2 through the bus line 5. Based on this, the IFIC 2 converts the charge amount by the first and second signals into a digital amount and outputs it to the CPU 1 through the bus line 5.
The first and second signals can be read by independent control signals. Then, the first signal relates to the following first distance, and the second signal relates to the second distance.

Next, FIG. 2 shows the first
How the relationship between the distance and the second distance changes will be shown and described. In the figure, the solid line shows the characteristic of the first distance, and the broken line shows the characteristic of the second distance.

According to the present invention, the first distance is made to have a certain width so as to have a predetermined distance range, and it is determined that a spot defect has occurred when the second distance is not allowed within the predetermined distance range. . Therefore, in the figure, the areas where the spot chipping is caused are A and B in the figure.

The first distance is obtained from the light receiving position of the light spot on the light receiving element (not shown) of the light spot light receiving section 4, and this light receiving position is linear with respect to the reciprocal of the distance to the object 6 to be measured. Is. Therefore, when the object 6 to be measured, which is apt to cause spot defects, is at a long distance, the change in the first distance with respect to the movement of the light receiving position is large.

On the other hand, the second distance is only a multiple of the square root of 2 even if the amount of received light is halved due to spot missing. Therefore, it can be said that the second distance is less affected by the spot defect than the first distance.

In view of such a point, in the present invention, the second distance is selected in the areas A and B where the spot defect occurs, and the accuracy of distance measurement is improved. As a specific example, as shown in FIG. 3, what is supposed to be 8 m shows a first distance of 16 m or more when the spot is missing and the spot is only in the right half. On the other hand, the second distance is 1/2 the amount of light,

[0024]

[Equation 1] Becomes Also from this example, when spot missing occurs,
It can be seen that the second distance is more accurate. In addition, according to the present invention, the second distance is further properly corrected so that the influence of the spot defect is eliminated. This will be described later.

The principle of operation of the distance measuring device for a camera of the present invention has been described above. Next, the specific sequence of the CPU 1 based on the above principle of operation will be described in detail with reference to the flowcharts of FIGS. To do.

First, referring to the flow chart of FIG.
The main operation of the CPU 1 will be described. CPU1 is bus line 5
A control signal is sent to the IFIC2 via the
2 is set to the AF mode, and the light beam projecting unit 3 and the light spot light receiving unit 4 can be driven (step S1). Then C
The PU 1 operates the light spot projecting unit 3 to generate a first signal corresponding to the light receiving position of the light spot according to the distance to the object 6 to be measured and a second signal corresponding to the light receiving intensity of the light spot. Are taken into the IFIC2 (step S2).
Since the first and second signals are taken in and held as the electric charge of the capacitor (not shown) attached to the IFIC 2, it is not necessary to take the signals into the CPU 1 immediately. Next, the CPU 1 captures the first signal, converts the signal into a digital amount corresponding to the charge amount of the capacitor, and captures it in a RAM (not shown) in the CPU 1 (step S3).

Then, the CPU 1 fetches the second signal. This captured signal is the above-mentioned step S
Similar to 3, another second R in the CPU 1 as a digital quantity
It is taken into the AM (step S4). Subsequently, the first distance information calculated from the first signal is obtained and stored in the third RAM, and the second distance information calculated from the second signal is obtained and stored in the fourth RAM. Store (step S
5, S6).

Then, the CPU 1 determines from the relationship between the first distance information and the second distance information whether or not the light beam has a spot defect during distance measurement to the object to be measured (step S7). ). Incidentally, this step S7 will be described in detail later. Then CP
U1 performs a branching process according to the determination in step S7 (step S8). If there is a spot defect, the process proceeds to step S10. If no spot defect occurs, the process proceeds to step S9.

This step S9 is a process in which the first distance information obtained from the first signal is adopted as the final distance information because there is no spot defect. In this case, the result of AF as a camera is photographed using this first distance information.

A case will be described in which it is determined that there is a spot defect due to the branch in step S8. The arithmetic processing at this time shifts from step S10 to S11. When it is determined that the spot is missing, the second distance information is adopted as the final distance information (step S1).
0). This is because, as described above, the second distance information is less affected by the spot missing.

Then, a correction operation is added to the final distance information set in step S10 (step S1).
1). This is because the second distance information obtained in the processing step 6 is used to measure a relatively long distance, so that the distance measurement information becomes inaccurate in the distance measurement area where spot missing occurs. In addition, the correction amount is variable depending on whether the camera is held horizontally or vertically. Details of step S11 will be described later.

Next, the process of step S7 will be described in detail with reference to the flowchart of FIG. First C
PU1 multiplies the distance information 1 which is the first distance information by a coefficient 1 (step S21). The coefficient 1 is a change rate that the distance information 1 of a subject having a high reflectance can take.
There is no problem if the value is 0 or more, and in the case of the present invention,
The coefficient 1 is set to "2.0". The result of this calculation is stored in the CPU 1 as the determination data 1.

Next, the distance information 1 is multiplied by a coefficient 2 (step S22). The coefficient 2 is a change rate that the distance information 1 can take in a subject having a low reflectance, and if the numerical value is 1.0 or less, there is no problem, and in the case of the present invention, “0.5”.
And The result of the calculation in step S22 is stored in the CPU 1 as the determination data 2.

Subsequently, the CPU 1 compares the distance information 2 with the determination data 1 and, as a result of the comparison, if the distance information 2 exceeds the determination data 1, it is determined that there is a spot defect and the process proceeds to step S25. Let On the contrary, when the distance information 2 is less than the determination data 1, the process proceeds to step S24 (step S23).

In step S24, the distance information 2
When the distance information 2 is less than the determination data 2, it is determined that there is a spot defect and the process proceeds to step S25. When the distance information 2 is greater than the determination data 2, there is no spot defect. Then, the process proceeds to step S26 (step S24).

[0036] That is, in the step S23 and S24, and detects whether the second distance is within a predetermined distance range in FIG. 2 described above, when entry should not be, it is determined that the spot missing has occurred There is.

[0037] Thus, if it is determined that every spot missing, particularly a flag in CPU1 (not shown) as "1" (step S25), and if it is determined that the spot missing not every is the flag in the CPU1 as "0" (step S 26), and terminates the entire process (step S26,27).

Next, the processing of step S11 will be described with reference to the flowchart of FIG. The process of step S11 is a correction process for setting the distance information 2 as the final distance information when it is determined that there is a spot defect in the process of step S7. In this operation, first, the CPU 1 compares the distance information 2 with the near and far threshold data (step S31). Subsequently, if it is determined that the distance information 2 is farther than the near / far threshold value, the process proceeds to step S36, and if it is determined to be near, the process proceeds to step S33.

First, in the processing on the near side (branching to NO in step S32), the CPU 1 determines whether or not the camera is in the lateral position based on an input from a position sensor (not shown) (step S33). Then, in the case of the vertical position (branching to NO in step S33), the constant A is substituted into the constant k1 and the constant B is substituted into the constant k2 (step S35).
On the other hand, in the lateral position (YES in step S33)
In step S34, the constant C is substituted for the constant k1 and the constant D is substituted for the constant k2 (step S34). Then, after the numerical values are substituted into the constants in steps S34 and S35, the process proceeds to step S39.

The remote side (YES in step S32)
In the processing of (branch to), the CPU 1 determines whether the lateral position of the camera is based on an input from a position sensor (not shown) (step S36). Then, in the case of the lateral position (step S36), the constant E is substituted for the constant k1 and the constant F is substituted for the constant k2 (step S38). On the other hand, in the case of the vertical position, the constant G is substituted for the constant k1 and the constant H is substituted for the constant k2 (step S3).
7). Then, after the numerical values have been assigned to the constants in steps S37 and S38, the process proceeds to step S39.

Thus, in step S39, the distance information 2 is multiplied by the constant k1 and the result is multiplied by the constant k2.
Is output as final distance information, and the process returns to the main routine. As a result, it is possible to perform correction to an optimum value regardless of the distance to the subject and the way the camera is held (step S40).

As described in detail above, in the distance measuring device for a camera of the present invention, the first distance corresponding to the incident position of the spot light on the light receiving element (not shown) of the light spot light receiving section 4 and the spot light. The second distance corresponding to the incident intensity is calculated, and the first distance is calculated.
If the second distance is not allowed within the range by providing a predetermined width for the distance of, it is determined that a spot defect has occurred,
The second distance is selected and used with a predetermined correction.
Therefore, the influence of the lack of the spot of the light beam is reduced, and erroneous distance measurement can be reduced.

According to the above embodiment of the present invention, the following constitution can be obtained. (1) A light projecting unit for irradiating a light beam toward an object to be measured, and a light receiving optical system arranged at a predetermined distance from the light projecting unit and receiving a light beam reflected from the object to be measured. Corresponding to the light receiving element that is arranged near the image plane of the light receiving optical system and receives the condensed spot light from the object to be measured and photoelectrically converts it, and the incident position of the spot light on the light receiving element A distance measuring device for a camera, comprising: a calculating unit that calculates a distance to an object to be measured based on the first signal and the second signal corresponding to the incident intensity of the spot light. . (2) First calculation means for calculating the distance to the object to be measured based on the first signal and outputting the first distance signal, and the object to be measured based on the second signal. Second calculation means for calculating a distance to an object and outputting a second distance signal, and the second distance within a predetermined area in which the first distance signal is widened to a short distance side and a long distance side. Selecting means for determining whether the signal is included, selecting the first distance signal when determining that the signal is included, and selecting and outputting the second distance signal when determining that the signal is not included. A distance measuring device for a camera. (3) First calculation means for calculating the distance to the object to be measured based on the first signal and outputting the first distance signal, and the object to be measured based on the second signal. Second calculation means for calculating a distance to an object and outputting a second distance signal, and the first distance in a predetermined area in which the second distance signal is widened to the short distance side and the long distance side. Selecting means for determining whether the signal is included, selecting the first distance signal when determining that the signal is included, and selecting and outputting the second distance signal when determining that the signal is not included. The distance measuring device for a camera according to (1) above. (4) It is determined that a spot defect has occurred in the reflected spot light from the object to be measured when the second distance signal is selectively output by the selection means, and the light amount reduction due to the spot defect is corrected. (3) The distance measuring device according to (3) above. (5) The camera distance measuring device according to (4), wherein the correction is performed by changing a correction amount according to a distance to an object to be measured. (6) When the second distance signal is selectively output by the selecting means, it is determined that a spot defect has occurred in the reflected spot light from the object to be measured, and the first distance signal of the first distance signal due to the spot defect is detected. The camera distance measuring device according to (2) or (3), wherein the calculation error is corrected after using the second distance signal and then output. (7) The camera distance measuring device according to (6), wherein the correction is performed by changing a correction amount according to a distance to an object to be measured. (8) In the distance measuring device for a camera according to (6), the correction amount is changed depending on whether the camera is in a horizontal position or a vertical position.

[0044]

As described above, according to the present invention, it is possible to provide a simple and inexpensive distance measuring device which corrects so as to reduce the influence of spot missing of a light beam and prevents erroneous distance measurement.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a distance measuring device for a camera of the present invention.

FIG. 2 is a diagram for explaining which of a first distance and a second distance is to be selected and which one to select when a spot defect occurs.

FIG. 3 is a diagram showing a concrete state of spot missing.

FIG. 4 is a flowchart for explaining the operation of CPU 1.

5 is a flowchart showing a sequence executed in step S7 of FIG.

FIG. 6 is a flowchart showing a sequence executed in step S11 of FIG.

FIG. 7 is a diagram for explaining a spot defect that occurs when distance measurement is performed by a distance measuring device that adopts a triangulation distance measuring method according to a conventional technique.

8 is a diagram showing a light receiving range on the light receiving element 14 of FIG. 7 together with spot defects.

[Explanation of symbols]

1 ... CPU 2 ... IFIC 3 ... Light spot projector 4 ... Light spot light receiving part 5 ... Bus line

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiichi Mori 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (56) Reference JP-A-4-48208 (JP, A) JP Sho 62-9212 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 7/32 G01C 3/06 G03B 13/36

Claims (9)

(57) [Claims] 1. A light projecting means for projecting a spot light flux toward a subject, and a light flux reflected from the subject by the spot light flux is received.
The first signal corresponding to the incident position of the reflected light flux and
Output a second signal corresponding to the incident intensity of the reflected light flux
The light receiving means, the first distance information based on the first signal, and the second distance information.
Distance information calculator for calculating second distance information based on signals
A step, comparing the first distance information and the second distance information,
According to the comparison determination means for determining the relationship between the two and the comparison determination result of the comparison determination means, the first
Selection means for selecting distance information or the second distance information
And based on the distance information selected by the selecting means,
And a subject distance determining means for determining a distance to a subject . 2. The comparison / determination means is configured to detect the first distance information.
The value of the second distance information is included in a predetermined area including the information value.
A contract characterized by making a determination as to whether or not
The distance measuring device for a camera according to claim 1. 3. The predetermined area of the first distance information
A value in which a certain amount of value is added to the short distance side and the long distance side.
The range of the camera according to claim 2, wherein
Distance device. 4. The predetermined area defined by the comparison determination means.
If the second distance information is included in the
It is determined that no chipping has occurred, and the
Spot missing if second distance information is not included
Is further equipped with a spot defect determination means for determining that
The camera distance measurement according to claim 2, wherein the distance measurement is provided.
apparatus. 5. The selection means is based on the comparison / determination means.
The value of the second distance information is included in the predetermined area.
If it is determined that the first distance information is selected
Distance measurement of the camera according to claim 2 or 4, characterized in that
apparatus. 6. The subject distance determining means is the selection hand.
If the first distance information is selected by the step,
The first distance information is used as the subject distance without correction.
The distance measuring device for a camera according to claim 5, wherein: 7. The selection means is based on the comparison / determination means.
If the value of the second distance information is included in the predetermined area,
If it is determined that the second distance information is not selected,
The camera according to claim 2, wherein the camera is selected.
Ranging device. 8. The subject distance determining means is the selection hand.
If the second distance information is selected by the step,
Light intensity decrease due to spot missing for the second distance information
Claim to correct the subject distance to correct the minute
Item 5. The distance measuring device for a camera according to item 5. 9. The correction is made according to the distance to the subject.
The correction amount differs according to claim 8.
Camera distance measuring device.