JP3379834B2 - 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 camera distance measuring device capable of distance measuring for automatic focus adjustment in water and in air.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made regarding a distance measuring device for a camera capable of distance measuring for automatic focus adjustment in water and air. For example, JP-A-61-1
According to Japanese Patent No. 295533, a method is described in which it functions exactly like a camera provided with a normal automatic focus adjustment device (hereinafter referred to as AF) in the air and functions as a fixed focus camera in water. In this method, since the reflected signal light from the subject used for AF is greatly attenuated in water, the ratio of the signal due to the reflected signal light to the noise due to stationary light, so-called S / N cannot be sufficiently secured. Since there are many floating substances such as plankton, algae, and dust, the main measures are to prevent the main subject intended by the photographer from being floating substances such as plankton, algae, and dust, that is, difficult to distinguish Has become.

According to Japanese Utility Model Laid-Open No. 27435/1992, it is determined whether the camera is used underwater or on land, and the information sent to the focus detection device or the exposure control device is switched according to the determination result. Then, a method of switching aberration information such as spherical aberration and chromatic aberration, subject distance information, etc. depending on whether it is underwater or land is described. This method mainly deals with the aberration of the lens due to the refractive index of water generated in water.

[0004]

However, since the method according to Japanese Patent Laid-Open No. 61-295533 functions as a fixed-focus camera in water, when the distance in water is relatively large, It was not possible to take both a photograph of a diver, for example, and a close-up photograph underwater, for example, a photograph of coral, with the same exact focus.

Further, in the method disclosed in Japanese Utility Model Laid-Open No. 4-27435, the difference between the lens aberrations in water and air is merely taken as a countermeasure. Therefore, we did not consider the composition and subject of the underwater photograph and the photograph in the air, and the floating matters such as plankton, algae, and dust in the water were taken into consideration. There were times when you couldn't.

Explaining the composition between the above-mentioned underwater photograph and the photograph in the air, and the difference in the object to be photographed, for example, in the photograph in the air, as shown in FIG. The landscape may extend to. It is possible to make a photograph with a more vivid atmosphere by imprinting the landscape 5 and the like on the photographing screen 6 in addition to the person 5 as the main subject. Therefore, the person 5, which is the main subject, often does not always exist in the center of the front of the shooting screen 6.

However, in water, due to the transparency and the transparency of water, the background cannot be seen at a considerable distance, and many objects within the photographing screen are at a short distance. Further, in water, as shown in FIG. 2B, in many cases, floating matter 7 such as plankton, algae and dust is present in front of the fish 8 which is the main subject. Therefore, unlike in the case of underwater, there is a need for a method of accurately focusing on the fish 8, which is the main subject, without being confused by the floating substances 7 such as plankton, algae, and dust, unlike the case of underwater.

That is, the main reason why the main subject cannot be focused is that, in the air, the vast background is in focus, that is, the background other than the main subject is in focus. Also, in water, a miscellaneous subject in front is in focus.

Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a distance measuring device for a camera which can easily focus on a subject intended by a photographer in water and in the air. To do.

[0010]

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 determining means for determining whether or not the camera is used underwater, and the camera. It is possible to measure multiple points in the central part and the peripheral part of the shooting screen of
In addition, the distance measuring means in which a plurality of distance measuring points are arranged adjacent to each other and the use state of the camera by the determining means are water.
If it is determined that it is in the middle, it is adjacent to the central part from the plurality of points that can be measured by the distance measuring means.
Selection means for selecting a plurality of distance measuring points arranged ,
The distance measuring means is provided by the selecting means.
Multiple distance measuring points adjacent to the center are selected.
If multiple points are placed adjacent to this central part,
The distance for focusing and the distance for focusing based on the distance measurement result
It is characterized by determining .

According to a second aspect of the present invention, there is provided a camera distance measuring device according to the first aspect.
The distance measuring means is arranged adjacent to the central portion by the selecting means.
If multiple ranging points that have been placed are selected, this
Distance measurement of multiple points arranged adjacent to the center,
If there are multiple equal distance measurement results,
It is characterized in that the distance measurement result is determined as the focusing distance .

[0012]

[0013]

In the distance measuring device for a camera of the effects of the present invention, whether used state of the camera is underwater Ru determined by the determination means. Then, thus the use of the camera in this determination means
If it is determined that the condition is underwater, it is adjacent to the center from the above points that can be measured by the distance measuring device.
Arranged plurality of distance measuring points Ru is selected by the selection means. And the central part selected by this selecting means
A plurality of distance measuring points arranged adjacent to
Focusing is performed based on the distance measurement result
The working distance is determined .

Further, the distance measured by the distance measuring means is measured.
If there is an equal distance measurement result in the distance measurement results,
The distance result is determined as the focusing distance .

[0015]

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a conceptual configuration of a camera to which a distance measuring device according to an embodiment of the present invention is applied.

A so-called multi-point distance measuring unit (multi-distance measuring unit) 1 capable of measuring distances at a plurality of points on the photographing screen outputs the distance measuring result to the selecting unit 2. In addition, the underwater determination unit 3 that determines whether the camera is used underwater or in the air outputs the determination result to the selection unit 2.

Then, the selecting section 2 determines the focusing distance according to the distance measurement result and the determination result, and controls the focusing section 4 for driving the photographing lens to perform the focusing. To do.

In the distance measuring device of the camera having the above-described structure, the distance can be measured at a plurality of points within the photographing screen. As a result, in the air (on land) as shown in FIG.
Even if the person does not exist in a predetermined place, for example, near the center, accurate focusing can be performed on the person.

Further, in the underwater scene as shown in FIG. 2B, the fish 8 which is the main subject is brought into focus while canceling the distance measurement result of the miscellaneous subject such as the floating object 7 in the photographing screen 6. be able to.

In the above embodiment, the distance measuring device capable of measuring a plurality of points is used as the multi-point distance measuring unit 1, but the distance measuring device capable of measuring a plurality of points is not always required. However, it may be a one-point distance measuring device having a function of detecting a rough subject and measuring one point.

FIG. 3A is a diagram showing the structure of a camera to which the distance measuring apparatus according to the first embodiment of the present invention is applied. In the figure, a CPU (Central Processing Unit; C)
PU) 10 is provided with three light emitting diodes (hereinafter referred to as LEDs) 12 with respect to driver 11 in multipoint distance measuring unit 1.
The light emission of a, 12b, and 12c is instructed. Driver 1 above
The LED 1 causes a pulsed current to flow through the LEDs 12a, 12b, 12c to cause the LEDs 12a, 12b, 12c to emit pulsed light.

The light from the LEDs 12a, 12b and 12c is projected through the light projecting lens 13 as light for distance measurement in three directions. FIG. 3B shows projection points 14a, 14b, 14c in the photographing screen 6 of the distance measuring light at this time.
FIG.

Each of the distance measuring lights projected in this manner is reflected by the subject. The reflected signal light is condensed by the light-receiving lens 15 provided so as to be separated by a predetermined base line length. Then, they respectively enter the optical position detecting elements (hereinafter referred to as PSD) 16a, 16b, 16c. The above P
SD is a semiconductor element that outputs two current signals depending on the position and amount of incident light, and is widely used in distance measuring devices.

On the PSDs 16a, 16b, 16c, in addition to the reflected signal light, light from the background illuminating the subject such as the sun or an electric lamp is also incident. Therefore, a direct current (DC) light removing circuit 17 having a function of removing a direct current caused by light from these backgrounds is provided.

On the other hand, the current output from the PSDs 16a, 16b, 16c based on the reflected signal light is
It becomes a pulsed signal current. Therefore, it is amplified by the preamplifiers 18 and 19 and the transistors 20 and 21 without being affected by the DC light removing circuit 17.

The signal current thus flowing into the bases of the transistors 20 and 21 and amplified as a collector current together flows into the resistor 22, and passes through the analog / digital (hereinafter referred to as A / D) converter 23. CPU10
Entered in.

On the other hand, the emitter currents of the transistors 20 and 21 are passed through the diodes 28 and 29 by the current mirror circuit composed of the diode 24 and the NPN transistor 25, and the diode 26 and the NPN transistor 27.

The signal current amplified by the current mirror circuit is current-voltage converted by the diodes 28 and 29. At this time, the converted voltage has a logarithmically compressed form due to the I / V characteristics of the diodes 28 and 29.

This voltage is input to the differential expansion circuit composed of the transistors 32 and 33 via the buffers 30 and 31. The emitters of these transistors 32 and 33 are both connected to the constant current source 34.

Let Iφ be the current value of the constant current source 34, and P
Let I1 and I2 be the two output currents from SD16a, 16b, and 16c, respectively.
Can be expressed by I OUT = I 1 / (I 1 + I 2) · Iφ (1) This I1 / (I1 + I2) is
It is proportional to the light incident position of the reflected signal light from the subject on each PSD 16a, 16b, 16c.

Therefore, the CPU 10 controls the LEDs 12a,
If the voltage across the resistor 35 is received via the A / D converter 23 at the light emission timings 12b and 12c, the CPU 1
0 indicates each projection point 14a, 1 due to the principle of triangulation.
The subject distances of 4b and 14c can be calculated.

In the underwater determination unit 3, the CPU 1
0 causes the light projecting element 41 to project light through the light projecting circuit 40. The output light of the light projecting element 41 enters the light receiving element 43 through the prism 42.

At this time, the reflection of the output light from the prism 42 is established under the condition of the critical angle based on the refractive index of the light in the air. Therefore, when the reflecting surface of the prism 42 comes into contact with water, no reflection occurs and the output from the light receiving element 43 decreases.

As described above, the CPU 10 controls the light projecting circuit 40, amplifies the output from the light receiving element 43, and monitors the output from the light receiving circuit 44 so that the camera is used underwater. Determine if used in air.

A first release switch (hereinafter referred to as 1stSW) 50 is provided on the release button of this camera.
And a second release switch (hereinafter referred to as 2ndSW) 51. The CPU 10 controls the multi-point distance measuring unit 1 and the underwater determination unit 3 from the ON and OFF states of the two 1st SW 50 and the 2nd SW 51, and controls the focusing unit 4 according to the output result.

In the focusing section 4, the CPU 1
0 drives the motor 53 via the motor driver 52. By driving the motor 53, the focusing lens 54 is moved to focus on the subject.

Further, in the above structure, the multi-point distance measuring section 1 is provided with three PSDs, but it may be provided with five PSDs. With such a configuration, as shown in FIG. 3C, it is possible to measure the distances of the five projection points 14a, 14b, 14c, 14d, and 14e in the photographing screen 6, and the accuracy of the distance measurement result is improved. It is possible to raise. Although the projection points 14d, 14b, and 14e shown in FIG. 3C are arranged in the vertical direction, they may be arranged adjacent to each other and may be arranged in any direction.

In the above structure, the LEDs 12a, 12
Although the projection points b and 12c are used for projection, the xenon discharge arc tube (hereinafter, referred to as Xe tube) may be used for scanning instead to project the projection point.

FIG. 4 is a flow chart showing the processing of the CPU 10 as the operation of the camera to which the distance measuring apparatus of the first embodiment is applied. This is 5 PS as mentioned above
6 shows the processing of the CPU 10 of the camera of the first embodiment, which is configured to include D and is capable of measuring the distance of the five projection points 14a, 14b, 14c, 14d, and 14e in the photographing screen 6.

In step S1, the CPU 10 determines on / off of the 1st SW50 which is closed while the release button of the camera is being pressed. Here, when the 1st SW 50 is turned on, the CPU 10 controls the light projecting circuit 40 and simultaneously monitors the output of the light receiving circuit 44. As a result, it is determined whether the environment in which the camera is used is underwater (step S2).

Subsequently, when it is determined to be underwater, the process proceeds to step S3, and the projection points 14b, 14d, 14e at the central portion within the photographing screen 6 are shown in FIG. 3C.
The three projection points are sequentially measured. Then, the distance measurement results are set to Lb, Ld, and Le. The three projection points 14b, 14d, and 14e are shown in FIG.
They are adjacent as shown in (c). As a result, ideally, all the distance-measuring lights (distance-measuring beams) are projected onto the same main subject 55 as shown in FIG.
The distance measurement results of the two projection points should be equal.

However, in water, planks, algae, dust, and other floating matter 56 as shown in FIG. 5 often obstruct the optical path of the distance measuring light. Therefore, not all distance measurement results Lb, Ld, and Le are necessarily equal.

Therefore, in the next step S4, it is determined whether or not there are equal distance measurement results of two or more points among the distance measurement results of the above-mentioned three projection points. If two or more points have the same distance measurement result, the distance measurement result is set as the focusing distance Lp (step S5). That is, in the first embodiment, as described above, in the steps S4 and S5, the distance measurement result of two equal distance measurement results among the three distance measurement results is set as the focusing distance Lp by the majority decision.

On the other hand, in step S4, if none of the distance measurement results of the three projection points are equal, the process branches to step S10. In step S10, the CPU 10 determines whether or not there are large variations in the distance measurement results of the above-mentioned three projection points. Here, when the variation of the distance measurement result is large, that is, when the variation of the three adjacent projection points is large, the distance measuring light hits the miscellaneous subject which is the floating object 56 floating in front of the main subject 55. Ignore this as the probability is high. Then, in the next step S11, the second closest distance is set as the focusing distance Lp, and the process proceeds to step S6.

On the other hand, in step S10, when the variation in the distance measurement result is not large, the process branches to step S12, and the distance measurement result Lb at the center of the photographing screen is set to the focusing distance Lp.
Then, the process proceeds to step S6.

Next, in step S6, it is determined whether the 2nd SW 51 which is closed by pushing the release button of the camera to the end is turned on or off. Here, when the 2nd SW 51 is turned on, the process proceeds to step S7. In step S7, the CPU 10 controls the focusing unit 4 to focus using the focusing distance Lp obtained in the above step.

At this time, the distance measurement result in water is measured as a shorter distance than the actual distance due to the influence of the refractive index of water. Therefore, the focusing section 4 needs to extend the focusing lens 54 in consideration of the refractive index of water. CPU10
In consideration of the refractive index of water, the distance measurement result in water is converted into the actual subject distance, the amount of extension of the focusing lens 54 is determined, and focusing is performed.

Succeedingly, in a step S8, a shutter (not shown) is controlled to perform exposure. Then, this process ends. Further, in step S6, the 2nd SW51
When is off, the process proceeds to step S9. In this step S9, it is determined whether the 1st SW50 is on or off.
Here, if the 1st SW50 remains on, the process returns to step S6. On the other hand, when it is off, step S1
Return to.

If it is determined in step S2 that the camera is not used in water, that is, in the air, the process branches to step S13 and the projection points 14a, 14b, 14c shown in FIG. The distance is measured at three points. This is to enable the distance to the person 5 to be measured even in a scene where the person 5 as the main subject does not exist near the center of the shooting screen 6 as shown in FIG. 2A. . Therefore, in the next step S14, the CPU
Reference numeral 10 selects the closest distance from these distance measurement results and sets it as the focusing distance Lp. This step S
In 14, a known selection method other than the closest selection may be used.

Next, in step S15, the CPU 10 determines whether the 2nd SW 51 is on or off. Where 2n
When the dSW 51 is on, the process proceeds to step S16. In step S16, the CPU 10 controls the focusing unit 4, and the focusing unit 4 focuses on the subject based on the focusing distance Lp obtained in the above step. Then, the process proceeds to the next step S8. Since the camera is used in the air and the subject is in the air for focusing in step S16,
It is not necessary to correct the refractive index difference as described in step S7 above.

In step S15, 2ndS
When W51 is off, the process proceeds to step S17. In this step S17, the 1st SW50 is turned on / off.
Determine off. Here, when the 1st SW50 remains on, the process returns to step S15. On the other hand, when it is off, the process returns to step S1.

Then, in the next step S8, a shutter (not shown) is controlled to perform exposure. Then, this process ends. As described above, in the first embodiment, the distance measurement point (projection point) is assumed in water and in the air, assuming a scene as shown in FIGS. 2 (a) and 2 (b).
Have changed. As a result, the distance to the main subject can be measured without failure.

Further, at the time of distance measurement in water, the distance measurement results of a plurality of distance measurement points are compared and the more reliable distance measurement result is used for focusing. That is, specifically, when there is a difference in the distance measurement results of the three adjacent distance measurement points, the distance to the main subject is determined by majority voting.

However, it is conceivable that, of the distance measurement for the three distance measurement points, two distance measurement points may deviate from the main subject. At this time, the two distance measuring points indicate the distance to the background. Therefore, in this case, with a simple majority decision, the background will be in focus, so
As a countermeasure, the distance measurement result beyond a predetermined distance may be excluded.

As described above, in the first embodiment, it is determined whether the environment in which the camera is used is underwater or air, and the distance measurement points suitable for each environment are set according to the result. In addition, the method for determining the focusing distance from the results of distance measurement obtained from multiple distance measurement points can be switched between underwater and air, so it will be possible to use both in water and in air. It is possible to provide a camera that can focus on a main subject without being confused by the subject.

Next, a camera to which the distance measuring apparatus according to the second embodiment of the present invention is applied will be described. FIG. 6 is a diagram showing a configuration of a light projecting / receiving unit in the distance measuring apparatus according to the second embodiment.

This light projecting / receiving section has a light emitting element 61, a light projecting lens 63 for projecting light from the light emitting element 61 onto a main subject 62, and a predetermined distance so as to sandwich the light projecting lens 63. Arranged light receiving lenses 64a, 64b
And PSDs 65a and 6 that receive the reflected signal light from the main subject 62 via these light receiving lenses 64a and 64b.
5b and.

In the first embodiment, the distance measuring light is correctly detected by referring to the distance measurement results of the adjacent projection points shown in FIG. 5 by the projection pattern shown in FIG. 3C. It was determined whether the image was projected on the main subject. However, in the second embodiment, the two PSDs 65a and 65 are
Based on b, it is determined whether the distance measuring light 66 is completely projected onto the main subject 62.

As shown in FIG. 6, when the suspended matter 67 does not exist in the optical path of the distance measuring light 66, the distance measuring light 66 enters the PSDs 65a and 65b in the optical paths of 66a and 66b. At this time, assuming that the light incident positions on the PSDs 65a and 65b are Xa1 and Xb1, the light emitting element 61 and the light projecting lens 6 have the relationship of Xa1 = Xb1.
3, light receiving lenses 64a and 64b, PSDs 65a and 65b
To place.

In the above-mentioned structure, when the floating object 67 enters the optical path of the distance measuring light 66, the PSD at this time
Light incident positions Xa2 of the reflected signal light on 65a and 65b,
Xb2 is out of balance and has the following relationship.

Xa2 ≠ Xb2 Therefore, from the respective outputs of the PSDs 65a and 65b, the light incident position X of the reflected signal light on the PSDs 65a and 65b is X.
By determining a and Xb and comparing them, it is possible to determine whether or not the reflected signal light from the floating material 67. That is, 2
When the two light incident positions Xa and Xb are equal, it is considered that all the distance measuring lights are correctly projected onto the main subject 62. On the contrary, when the two light incident positions Xa and Xb are not equal to each other, it is considered that the distance cannot be accurately measured because the floating object 67 exists in the optical path of the distance measuring light 66. To be

The second embodiment is constructed by using the above-described method for determining the presence / absence of floating objects. Figure 7
It is a figure which shows the structure of the camera to which the distance measuring apparatus of 2nd Example which concerns on this invention is applied.

In the figure, the light projecting lens 63, the light receiving lenses 64a and 64b, and the PSDs 65a and 65b are as already described. The PSD 65a, 6
AF circuits 60a and 60b similar to the AF circuit 60 in the broken line shown in FIG. 3A are connected to 5b, respectively.

A Xe tube 69 is used as the light projecting element 61. In addition, as the light projecting element 61, the above Xe
It is not limited to the tube 69, and a plurality of LEDs may be used. Further, a capacitor 70 that stores energy for causing the Xe tube 69 to emit light, and a booster circuit 71 that charges the capacitor 70 with electric charges are provided.

A switch 72 is provided in the discharge path between the capacitor 70 and the Xe tube 69. And CPU
By turning on / off this switch 72,
The light emission of the Xe tube 69 is stopped (turned off). To start (turn on) the light emission of the Xe tube 69, the trigger circuit 73 applies a high voltage to the Xe tube 69 according to an instruction from the CPU 10, and the above X
This is performed by ionizing the inside of the e-tube 69 and promoting discharge.

Further, a mask 74 having a minute opening is provided in front of the Xe tube 69, and only the light emitted from this opening is projected onto the subject. At this time, the CPU 10 rotates the motor 76 via the motor driver 75. By rotating the motor 76 and moving the feed screw 77, the mask 74 can scan in the direction of the arrow shown in FIG.

By controlling the light emission of the Xe tube 69 while scanning the mask 74 in this way, the projection points of the distance measuring light can be changed to 78a, 78b, 78c shown in FIG. Further, the focusing portion 4 is provided as in the first embodiment.

FIG. 8 is a flow chart showing the processing of the CPU 10 as the operation of the camera to which the distance measuring apparatus of the second embodiment is applied. In step S101, the CPU 10
Is the 1st that closes while pressing the release button of the camera
Determine whether SW50 is on or off. Here, 1stSW
When 50 is turned on, a variable n indicating the light emission point
Then, the variable m indicating the number of distance measurement data is reset (step S102).

Next, in step S103, the underwater determination unit 3 is used to determine whether or not the environment in which the camera is used is underwater (step S103). Here, when it is determined to be underwater, the process proceeds to step S104.

In step S104, the Xe tube 69 is triggered by a high voltage to emit light, and the PSDs 65a and 65b are discharged.
The light incident positions Xa and Xb of the reflected signal light on the top are calculated.
This calculation is performed by I OUT, which is proportional to the light incident position on the PSD, shown in the above equation (1), that is, the AF circuit 60a,
The output from 60b is input to the CPU 10 and the CPU 1
0 does.

Succeedingly, in a step S105, the CPU 1
0 determines whether or not the light incident positions Xa and Xb of the reflected signal light on the PSDs 65a and 65b are equal. Here, when they are equal, as described above, it is considered that all the distance-measuring light projected at this time correctly hits the subject. Therefore, assuming that the distance measurement result at this time is reliable, the variable m indicating the number of distance measurement data is incremented in step S106. In the next step S107, the CPU 10 sets the distance measurement result obtained from the light incident position Xa to Lm.

On the other hand, in step S105, when the light incident positions Xa and Xb are not equal to each other, as described with reference to FIG. It is thought that it is not done. Therefore, step S1
06 processing, without performing the distance measurement calculation in step S107,
It branches to step S108.

In step S108, the variable n indicating the number of light emitting points is incremented. Next step S
At 109, it is determined whether or not the variable n indicating the number of light emission points has become "6". Here, when the value becomes "6", the process proceeds to step S110. On the other hand, until the value becomes "6", in step S118, the motor 76 is rotated by a predetermined amount to scan the mask 74, and the process returns to step S104 for detecting the light emission and the light incident positions Xa and Xb.

In step S118, the motor 76 is rotated by a predetermined amount to scan the mask 74. By repeating such scanning and light emission, the projection is performed on the six projection points in the photographing screen. , Distance measurement becomes possible. However, because of the branching step of step S105, the number of light projection points n and the obtained number of distance measurement data m do not necessarily match.

For example, in the water of a lake with many floating substances,
In some cases, the light incident positions Xa and Xb of the reflected signal light at all projection points may not match. At this time, the number of distance measurement data is m
= 0. Therefore, when the number of pieces of distance measurement data m = 0 in step S110, the process branches to step S117 to fix the focusing distance Lp to 1.5 m. If the main subject is present at a short distance, the amount of water between the main subject and the camera is reduced, and it is considered that the subject is less likely to be affected by the floating matter. Therefore, in the case of branching to step S117, the subject distance is considered to be relatively long, so a distance of 1.5 m, which is near the ordinary focal length, is selected.

On the other hand, in step S110, when the distance measurement data number m is not 0, the obtained distance measurement results L1 to L
The closest distance (closest distance) is selected from m and set as the focusing distance Lp. If the obtained distance is only one of L1, it is set as the focusing distance Lp (step S111).

Next, in step S112, the CPU 10
Determines ON / OFF of the second SW 51. Where 2
When the ndSW 51 is on, the process proceeds to step S113. In step S113, the CPU 10 controls the focusing unit 4, and the focusing unit 4 focuses on the subject based on the focusing distance Lp obtained in the above step. In the next step S114, exposure is performed by controlling a shutter (not shown).

In step S112, 2nd
If SW51 is off, the process branches to step S116. In step S116, it is determined whether the 1st SW50 is on or off. Here, if the 1st SW50 remains on, the process returns to step S112. On the other hand, when it is off, the process proceeds to step S115.

Subsequently, in step S115, the mask 7
The motor 76 for moving the mask 4 is reversely rotated by a predetermined amount to move the mask 7
Initialize position 4. Then, this process ends. On the other hand, when it is determined in step S103 that the camera use environment is not underwater, that is, when the camera use environment is in the air, the process proceeds to step S119.
In step S119, the Xe tube 69 is triggered by a high voltage to emit light, and the light incident positions Xa and Xb of the reflected signal light on the PSDs 65a and 65b are calculated.

When the environment in which the camera is used is in the air, it is not necessary to consider the influence of suspended matter. Therefore, the size comparison of the light incident positions Xa and Xb of the reflected signal light is not performed unlike the processing in step S105.

Here, even if there is a difference between the light incident positions Xa and Xb as in the case of measuring the distance of the floating substance 67 shown in FIG. 6, it is possible to obtain an accurate value by calculating (Xa + Xb) / 2. Taking advantage of the optical system having the configuration shown in FIG. 6 that distance measurement is possible, the distance measurement values of the respective projection points are calculated one after another in step S120.

Therefore, in the next step S121,
The variable n indicating the number of light emitting points is incremented, and in step S122, the end judgment of the number of light emitting points is set to "1.
It is set to 0 "and the judgment is made.

That is, in the air, as shown in FIG. 2A, the person 5 who is the main subject up to the peripheral portion of the photographing screen 6
Is likely to exist. Therefore, the above step S12
To determine the number of light emission repetitions in 2, set the number of light emission points to 1
It is devised so that the distance can be measured to the peripheral area of the screen even if it is 0 times.

In step S122, it is determined whether or not the variable n indicating the number of light emitting points has become "10".
Here, when the value becomes “10”, the process proceeds to step S123. On the other hand, until it becomes “10”, step S1
At 24, the motor 76 is rotated by a predetermined amount, the mask 74 is scanned, and the process returns to step S119 in which light emission and light incident positions Xa and Xb are detected. That is, similar to step S118, the mask 74 is moved by a predetermined amount,
Repeat distance measurement at different projection points.

If it is determined in step S122 that the distance measurement of the 10 projection points has been completed, the process proceeds to step S123. In this step S123, the closest distance is selected from the obtained distance measurement results of L1 to L10 and set as the focusing distance Lp. And step S1
Move to 12. The processing after step S112 is as described above. Incidentally, the above steps S109, S12
"6" and "10" in 2 are examples, and it suffices that the distance can be measured over a wider range in the air. Therefore, if the distance measurement intervals are the same, the number becomes larger in step S122.

As described above, in the second embodiment, 2
Using one light position detecting element (PSD), it is determined whether or not the distance measuring light is correctly projected onto the subject. Then, the distance measurement result of the projection point where the distance measuring light is not uniformly projected on the subject is invalidated. As a result, the influence of suspended matter can be suppressed as much as possible.

When all the distance measurement results are invalidated by determining whether or not the distance measurement light is correctly projected onto the subject using the two light position detection elements (PSD), the camera The focus position of is set to a fixed focus to prevent the photographed image from making a big mistake.

Further, in the second embodiment, how to use the light incident positions Xa and Xb of the reflected signal light from the subject is completely different depending on whether the camera is used in water or in air. did. That is, in water, the emphasis is on the projection point where the distance measuring light correctly hits the subject. on the other hand,
On land, even if the distance measuring light does not hit the subject correctly, the light incident positions Xa and Xb are combined to calculate an accurate distance, and the projection point indicating the closest distance from the obtained distance measuring results. Attach importance to.

This is based on the premise that in water there is often a small miscellaneous subject (floating object) in front of the main subject, and on land, such a case is unlikely. Furthermore, on land, it is assumed that the main subject is at the closest distance from the camera.

In addition, in the second embodiment, the idea of setting a fixed focus when it is determined that all distance measurement results are unreliable underwater can be applied without using the multi-AF. That is, in short-distance shooting, it is considered that the amount of water between the camera and the subject is small, and the amount of floating matter is small. At this time, it is considered that there is a high probability that Xa = Xb.

On the other hand, when photographing a long distance underwater, on the contrary, Xa
It is thought that there will be many scenes where Xb and Xb do not match,
At this time, focus on the normal focal length of 1.5 m,
You can use it as a pan focus. This is, so to speak, a concept like a distance measuring device that uses the amount of suspended matter, and is a concept that can be applied to a distance measuring device that can measure only one point.

In the flow chart shown in FIG. 8, the distance measuring correction and the focus correcting correction due to the difference in the refractive index of water are omitted in the drawings and description, but in reality, Some configurations require such correction.

According to the above embodiment of the present invention, the following configuration can be obtained. (1) Judgment means for judging whether or not the camera is used underwater, distance measurement means for measuring a plurality of points on the photographing screen, and the plurality of judgment means for judging the judgment result of the judgment means. A distance measuring device for an underwater camera, comprising: selecting means for selecting a distance measuring point from among the distance measuring points.

According to the distance measuring device for an underwater camera described in (1) above, since the distance measuring point is selected depending on whether or not it is underwater, erroneous distance measurement does not occur. (2) The distance measuring means is capable of measuring a distance between a plurality of adjacent distance measuring points and a plurality of distance measuring points distant from each other, and when the selecting means is determined to be underwater, the adjacent distance measuring points are detected. A plurality of distance measuring points to be selected are selected, and when it is determined that the distance measuring points are not underwater, the plurality of distance measuring points separated from each other are selected, and the distance measurement of the underwater camera according to (1) above is performed. apparatus.

According to the distance measuring device for an underwater camera described in (2) above, by selecting a distance measuring point depending on whether or not it is underwater, erroneous distance measurement is caused by floating substances such as algae and plankton in the water. There is nothing to do. It should be noted that the distance measuring points 1 shown in FIG.
4b, 14d, and 14e correspond to the distance measuring points that are distant from each other, the distance measuring points 14a, 14b, and
14c corresponds. (3) The distance measuring device includes a first distance measuring range and a first distance measuring range.
It is possible to perform multi-point distance measurement in a second distance measuring range wider than the second distance measuring range, and the selecting means selects the first distance measuring range when it is determined to be in water and is not in water. The distance measuring device for an underwater camera according to (1), wherein the second distance measuring range is selected when it is determined that

According to the distance measuring device for an underwater camera described in the above (3), it is unlikely that the main subject is present in the peripheral portion of the photographing screen when the subject is underwater, and the photographing screen when the subject is not underwater. Since there is a high possibility that the main subject also exists in the peripheral portion of, the optimum shooting range can be selected depending on whether or not the subject is underwater. The first distance measuring range means the distance measuring points 14b, 14d, 14 in FIG.
8 is a distance measuring range constituted by e, and in FIG. 8, it is a distance measuring range determined by the number of distance measuring points selected in step S109.

The second range-finding range is the range-finding range constituted by the range-finding points 14a, 14b, 14c in FIG. 3 (c), and in step S in FIG.
This is a distance measurement range determined by the number of distance measurement points selected by 122. (4) The distance measuring device for an underwater camera according to (1), wherein the selecting means changes the number of distance measuring points according to whether or not it is underwater.

According to the distance measuring device of the underwater camera described in (4) above, the optimum number of distance measuring points can be selected depending on whether or not the water is underwater. Note that changing the number of selected distance measuring points is described in step S109 and step S122 of FIG. (5) A determination unit that determines whether or not the camera is in use underwater, a distance measurement unit that can measure a plurality of points in the shooting screen, and a plurality of the plurality of determination units according to the determination result of the determination unit. A selection means for selecting a distance measurement value from the distance measurement results of the distance measurement points and a control means for controlling the focusing of the photographing lens of the camera according to the distance measurement value selected by the selection means are provided. Distance measuring device for underwater cameras.

According to the distance measuring device for the underwater camera described in (5) above, since the optimum distance measuring value can be selected depending on whether or not it is underwater, erroneous distance measurement is prevented. (6) The selection means, when the determination means determines that the subject is not underwater, selects the closest subject from the plurality of distance measurement values, and the determination means determines that the subject is underwater. At this time, if the reliability of the plurality of distance measurement values is low, the subject closest to the second distance measurement value among the distance measurement values is selected, and the distance measurement of the underwater camera according to (5) above is performed. apparatus.

According to the distance measuring device for an underwater camera described in (6) above, there is a possibility that a floating object such as algae or plankton may be measured when the distance measuring value is unreliable in water. Since it is high, it is possible to prevent erroneous distance measurement by selecting the second distance measurement value. (7) The selection means determines the reliability of the distance measurement value only when it is determined to be underwater, and invalidates the distance measurement value when the reliability is low. 5) An underwater camera distance measuring device described in 5).

According to the distance measuring device for the underwater camera described in (7) above, erroneous distance measurement is prevented by changing the method of selecting the distance measurement value in water where reliability is low. In the embodiment, step S105 in FIG.
The reliability is determined by. (8) Judgment means for judging whether or not the camera is used underwater, distance measuring means for measuring the distance of the subject within the photographing screen, and reliability of the distance measurement value by this distance measuring means. The focus value of the photographing lens of the camera is controlled on the basis of the distance measurement value obtained by the determination means and the distance measurement means, and when the determination means determines that the reliability is low, the distance measurement value obtained by the distance measurement means In place of the above, a distance measuring device for an underwater camera, comprising a control means for focusing at a predetermined distance.

According to the distance measuring device for an underwater camera described in (8) above, when the reliability is low, the distance is set to a predetermined distance, so that a photograph with a large blur does not occur. (9) The distance measuring means is capable of measuring distances for a plurality of subjects, the determining means makes a reliability determination for each of the plurality of distance measuring values, and the control means makes reliability for all distance measuring values. The range finder for an underwater camera according to (8) above, wherein the focusing is performed at the predetermined distance when the value is low.

According to the distance measuring device for an underwater camera described in (9) above, if there is at least one reliable distance measuring value, focusing is performed according to that distance measuring value, which causes a large blur. Never be. In the embodiment, the predetermined distance is set in step S117 of FIG. (10) Judgment means for judging whether the camera is used underwater or in the air, distance measuring means for measuring a distance between a plurality of points on the photograph screen, and the above-mentioned measurement according to the judgment result of the judgment means. And a switching unit for switching a distance measuring point of the distance unit. (11) Judgment means for judging whether the camera is used underwater or in the air, distance measuring means for measuring a plurality of points on the photographic screen, and distance measurement by the distance measuring means In a camera comprising a selection means for selecting one result from a plurality of distance measurement results, and a control means for controlling the focusing lens according to the result selected by the selection means, the selection means comprises: A camera characterized in that the selection method is switched according to the determination result of the determination means. (12) In the camera described in (11), the point closest to the center of the finder screen is selected at the time of the determination by the determination means. (13) The camera according to (11), wherein the focusing distance is selected according to a majority decision among the results obtained when the determination means determines that the subject is underwater. (14) The distance measuring unit projects the distance measuring light onto a plurality of points on the screen, and when the determining unit determines that the object is underwater, the plurality of distance measuring results are uniformly measured on the subject. The camera according to (11) above, wherein the distance measurement result of a point where the distance light is not projected is invalidated. (15) Discriminating means for discriminating whether the camera is in use underwater or in the air, and distance measuring light is projected onto the subject, and the reflected signal light is received to detect the distance to the subject. And a reliability determining means for determining the reliability of the distance measurement result. The reliability determining means includes: When the reliability of the distance measurement result is determined to be low and the determination unit determines to be underwater, the control unit fixes the focusing distance to a predetermined distance. And the camera.

According to the cameras of the above (10) to (15), erroneous distance measurement does not occur, so that a photograph with a large blur can be prevented. As described above, according to the first and second embodiments described above, it is possible to take a photograph with an accurate focus both in water and in the air.

[0106]

As described above, according to the present invention, it is possible to provide a distance measuring device for a camera which can easily focus on a subject intended by the photographer in water and in the air.

[Brief description of drawings]

FIG. 1 is a diagram showing a conceptual configuration of a camera to which a distance measuring device according to an embodiment is applied.

FIG. 2 is a diagram showing an example of a shooting screen for explaining the difference in composition and shooting target between a photograph in water and a photograph in air.

FIG. 3 is a diagram showing a configuration of a camera to which the distance measuring apparatus of the first embodiment is applied, and a diagram showing projection points thereof.

FIG. 4 is a flowchart showing the processing of the CPU 10 as the operation of the camera to which the distance measuring apparatus of the first embodiment is applied.

FIG. 5 is a diagram showing projection of distance measuring light (distance measuring beam) onto an underwater object in the first embodiment.

FIG. 6 is a diagram showing a configuration of a light emitting / receiving unit in a distance measuring apparatus according to a second embodiment.

FIG. 7 is a diagram showing a configuration of a camera to which the distance measuring apparatus of the second embodiment is applied.

FIG. 8 is a flowchart showing the processing of the CPU 10 as the operation of the camera to which the distance measuring apparatus of the second embodiment is applied.

[Explanation of symbols]

1 ... Multi-point distance measuring unit, 2 ... Selection unit, 3 ... Underwater determination unit, 4 ... Focusing unit, 5 ... People, 6 ... Shooting screen, 7 ... Floating object, 8
… Fish, 10… CPU (Central Processing Unit)
), 11 ... Driver, 12a, 12b, 12c ... Light emitting diode (LED), 13 ... Projection lens, 14a, 1
4b, 14c ... Projection point, 15 ... Light receiving lens, 16
a, 16b, 16c ... Optical position detection element (PSD), 17
... direct current (DC) light removal circuit, 18, 19 ... preamplifier,
20, 21 ... Transistor, 22 ... Resistor, 23 ... Analog / Digital (A / D) converter, 24 ... Diode, 2
5 ... NPN transistor, 26 ... Diode, 27 ... N
PN transistor, 28, 29 ... Diode, 30, 3
1 ... Buffer, 32, 33 ... Transistor, 34 ... Constant current source, 35 ... Resistor, 40 ... Projector circuit, 41 ... Projector element,
42 ... Prism, 43 ... Light receiving element, 44 ... Light receiving circuit, 5
0 ... First release switch (1st SW), 51
... second release switch (2ndSW), 52 ... motor driver (MD), 53 ... motor, 54 ... focusing lens, 60 ... AF circuit.

Claims (2)

(57) [Claims] 1. A determination means for determining whether or not a camera is used underwater , and a plurality of points can be measured in a central portion and a peripheral portion of a photographing screen of the camera. And further above the central part
, The distance measuring means in which a plurality of distance measuring points are arranged adjacent to each other and the use state of the camera by the judging means are underwater.
If it is determined that the distance is determined by the distance measuring means, the point is placed adjacent to the central portion from the plurality of points that can be measured by the distance measuring means.
Comprising selecting means for selecting a plurality of distance measuring points which, with said distance measuring means, next to the central portion by said selecting means
When multiple distance measuring points that are placed in contact are selected,
Distance measurement of multiple points arranged adjacent to this central part,
A distance measuring device for a camera, characterized in that the distance for focusing is determined based on the distance measuring result . 2. The distance measuring means is selected by the selecting means.
Select multiple distance measurement points adjacent to the center
If there are several poi adjacent to this central part,
The distance to the target, and multiple equal distances are included in the distance measurement results.
When there is a result, the distance measurement result is used for the focusing distance.
The distance measuring device for a camera according to claim 1, wherein