JP2001188293A - Polarized light removing device and photographic system using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem; in the case of introducing a method for comparing camera outputs while rotating the polarizing direction of a polarization liquid crystal filter at deciding the polarization component to be removed, the influence is given to a photographed image. SOLUTION: As for the polarized light removing device with a photographing polarization filter 3 for removing the polarization component in a specified polarizing direction out of light beams made incident on a photographing optical path 1, and filter setting means 7 to 12 for deciding the polarization component to be removed by the photographing polarization filter and actuating the photographing polarization filter, the polarization component to be removed by the photographing polarization filter is decided by the filter setting means based on the detection result of the polarization component included in the light received through optical paths 7 to 9 other than the photographing optical path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a photographing device such as a film camera, a video camera, and a television camera. The present invention relates to a polarization elimination device for suppressing the polarization.

[0002]

2. Description of the Related Art The reflected light described above contains a large amount of polarized light components, and the reflected light on the glass surface or the water surface overlaps with the original image of the subject, so that the subject becomes difficult to see. For this reason, the reflected light is often weakened by mounting a polarizing filter in front of the taking lens and rotating the polarizing filter so that its optical axis is orthogonal to the polarization direction of the reflected light.

However, in the method in which the photographer rotates the polarizing filter by hand while checking the image in the viewfinder, and seeks the rotational position of the polarizing filter at which the reflected light becomes the weakest, it takes time for this operation. More chances to miss out.

[0004] For this reason, proposals have been made to shorten the time by automating the setting of the polarizing filter so as not to miss a shooting chance.

More specifically, the liquid crystal directions are orthogonal to each other.
Two TN liquid crystal filters are superposed, and the camera outputs in each polarization direction are compared while rotating the polarization direction of the liquid crystal filter by 45 degrees. Then, the polarization direction of the liquid crystal filter is fixed with the direction with the lowest output as the polarization direction of the polarization component from which the reflected light is to be removed.

[0006]

However, in the above-mentioned proposal, first, a method is used in which the camera output is compared while rotating the polarization direction of the liquid crystal filter. If you rotate
Naturally, the photographed image will be affected. For this reason, it is not possible to frequently operate the polarization removing function during photographing.

Second, an expensive physical filter such as a liquid crystal filter and a control circuit for the filter are required to detect the polarization component to be removed in a short time. In addition, since the operation characteristics of the liquid crystal filter change depending on the temperature, it is difficult to obtain a stable polarization removing function.

Third, since the comparison of camera outputs when detecting the polarization component to be removed is a comparison of outputs having different times every several fields, it is erroneous in a situation where the subject or the illumination state is changing at high speed. It is likely to work.

Therefore, the present invention can determine the polarization component to be removed without affecting the photographed image, can be applied to a simple and inexpensive configuration such as rotating a polarization filter by a motor or the like, and can also be applied to the temperature change. Less susceptible,
It is another object of the present invention to provide a polarization removing device that is not affected by a change in a subject or an illumination state.

[0010]

In order to achieve the above-mentioned object, the present invention provides a photographing polarizing filter for removing a polarized component in a specific polarization direction from light incident on a photographing optical path, and the photographing polarizing filter. And a filter setting means for determining a polarization component to be removed and operating a photographing polarization filter, wherein the filter setting means includes a polarization component contained in light received through an optical path different from the imaging optical path. The polarization component to be removed by the imaging polarization filter is determined based on the detection result.

Specifically, the filter setting means is provided with a dedicated optical path juxtaposed to the photographing optical path or with an optical path which enters the photographing optical path and receives light separated from the photographing light in the photographing optical path. Or

That is, instead of using the photographing light as it is to determine the polarization component to be removed, the light received through an optical path different from the photographing optical path is used to determine the polarization component to be removed from the photographing light. In this way, it is possible to determine a polarization component to be removed without affecting a captured image, and to realize a polarization removal device that can be applied to a simple and inexpensive configuration such as rotating a polarization filter for photography with a motor or the like. I have.

Further, according to the present invention, since a configuration without using a liquid crystal can be adopted, a polarization removing device which is hardly affected by a temperature change can be provided.

In the above-mentioned invention, the specific configuration of the filter setting means is, for example, that each of a plurality of polarization components contained in the light received through the another optical path is photometrically detected, and the photometric result of the plurality of polarization components is detected. Is preferably determined as the polarization component to be removed by the imaging polarization filter. In this case, a plurality of photometric elements having sensitivity to polarization components having different polarization directions are used, and each polarization component is measured at the same time, and should be removed without being affected by a change in a subject or an illumination state. Preferably, the polarization component can be determined.

The operability may be improved by making this polarized light removing device detachable from the photographing device so that it can be attached to the photographing device only when necessary.

[0016]

(First Embodiment) FIG. 1 shows a photographing system according to a first embodiment of the present invention. In this figure, 1 is a taking lens, and 2 is a camera. As the camera 2, various cameras such as a film camera, a video camera, and a television camera are used.

In FIG. 1, a region surrounded by a dotted line indicates the above-mentioned polarization removing device.

Reference numeral 3 denotes a photographing polarizing filter that transmits polarized light in a specific direction and cuts orthogonal polarized light, and reference numeral 4 denotes a gear portion provided on the outer periphery of the photographing polarizing filter 3.

Reference numeral 6 denotes a motor, and reference numeral 5 denotes a gear for transmitting the rotation of the motor 6 to the gear unit 4.

Reference numerals 9 (9a to 9d) denote photometric elements. In this embodiment, four photometric elements 9 are provided as shown in FIG. Reference numeral 8 (8a to 8d) denotes a photometric polarizing filter disposed on the incident side of the photometric element 9, and 7 (7a to 7d).
d) is a small lens for guiding the subject light to the photometric element 9. The small lens 7, the photometric polarizing filter 8, and the photometric element 9 constitute a polarization component photometry unit. The polarization component photometry unit has a dedicated optical path provided in parallel with the imaging optical path formed by the imaging lens 1.

Reference numeral 10 denotes an amplifier for amplifying the output of the photometric element 9; 11 an arithmetic unit for comparing the outputs of the plurality of photometric elements 9;
Reference numeral 12 denotes a motor drive unit that drives the motor 6 based on the comparison result of the calculation unit 11.

The polarization component photometer and the amplifier 10
, The operation unit 11 and the motor drive unit 12 constitute a filter setting unit referred to in the claims.

Next, the configuration of the polarization component photometer will be described in detail with reference to FIG. In the polarization component metering unit of the present embodiment, the small lenses 7a to 7d are arranged close to each other after a part of the outer periphery of each of these four lenses is cut off. Photometric elements 9a to 9d are provided at the image image centers behind the small lenses 7a to 7d in the optical axis direction.

The photometric polarizing filters 8a to 8d are provided between the small lenses 7a to 7d and the photometric elements 9a to 9d.
Is installed. These photometric polarizing filters 8a to 8a
d is for cutting light (polarization components) having different polarization directions, and in this embodiment, the polarization directions of the photometric polarization filters 8a to 8d are changed by 45 degrees.

As described above, the photometric polarizing filters 8a to 8d
Is arranged, the outputs of the photometric elements 9a to 9d are
The light component in the polarization direction determined by the corresponding photometric polarizing filters 8a to 8d corresponds to the light component from which the light component has been removed.

The outputs from the photometric elements 9a to 9d are respectively amplified by an amplifier 10, and although not shown,
If necessary, after compression and characteristic correction, the operation unit 1
1 is input. The arithmetic unit 11 compares the four photometric outputs and selects the lowest one of the four photometric outputs.

This is because, when the light from the subject contains a polarized light component, the polarized light component is removed by the photometric polarizing filter, so that the output of the photometric element corresponding to the photometric polarizing filter is changed. It is because it becomes the lowest.

Thus, the rotation angle at which the photographing polarizing filter 3 is to be set, that is, the polarization component to be removed by the photographing polarizing filter 3 is determined.

The drive unit 12 rotates the motor 6 so that the photographing polarization filter 3 is oriented at the same rotation angle as the rotation angle of the photometric polarizing filter corresponding to the photometric element having the photometric output selected by the arithmetic unit 11. Let it.

The rotation of the motor 6 is transmitted via the gear 5 to the gear 4 of the polarizing filter 3 for photographing, and sets the rotating angle of the polarizing filter 3 for photographing to the above-mentioned rotation angle.

Since this series of operations is performed automatically,
The light incident on the lens 1 is obtained by removing reflected light containing a large amount of polarized light components reflected by glass, a water surface, or the like. The camera 2 records an easy-to-view image in which an image due to the reflected light is removed.

Here, even when the direction of polarization of the reflected light contained in the subject light does not always coincide with the direction of polarization removal by the photometric polarizing filters 8a to 8d, the rotation of the photometric polarizing filter corresponding to the photometric element having the lowest output. By rotating the photographing polarizing filter 3 to the corner, a practically sufficient effect can be obtained.

Further, by performing an interpolation operation in the operation section 11 and directing the photographing polarizing filter 3 to the estimated rotation angle, a more reliable effect can be obtained.

It is desirable to set the focal length so that the angle of view of the small lens 7 of the polarization component photometer is smaller than the angle of view of the photographing lens 1. In the opposite case, the outside polarization component that is not reflected in the photographing lens 1 is also detected, so that a photometric error increases, which eventually leads to a malfunction of the photographing polarizing filter 3.

The polarization elimination device of this embodiment can be detachably mounted on the front of the taking lens 1 as an integrated polarization elimination unit. Thus, it is possible to reduce the weight of the photographing lens 1 by mounting the polarization removing device only when reflected light (polarized light) is required, and removing it when unnecessary.

It should be noted that the lens may be detachable from the rear part of the lens. However, in this case, a lens system for maintaining the flange back is required.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
2 illustrates a polarization component photometry unit in the polarization removal device according to the embodiment. Note that the basic configuration of the polarization elimination device of the present embodiment is the same as that of the polarization elimination device of the first embodiment, and the polarization elimination device of the present embodiment has only the polarization component photometer shown in FIG. Things. In addition, components common to the first embodiment are denoted by the same reference numerals as in the first embodiment, and description thereof will be omitted.

The polarization component photometer of this embodiment includes two small lenses 27a and 27b, and these small lenses 27a and 27b.
b through the four photometric elements 29a to 29d
Beam splitter 33 that separates and enters the light
a, 33b.

Each of the photometric elements 29a to 29d is attached to a position on the polarization beam splitters 33a and 33b where a predetermined polarization component is efficiently incident.

By using the polarization component photometer having such a configuration, an effect of reducing the parallax between the four photometric elements 29a to 29d can be obtained.

In this embodiment, the photometric elements 29a to 29a
The outputs from 29d are amplified by an amplifier 10 and, if necessary, subjected to compression and correction of characteristics, and then processed by an operation unit 11d.
Is input to The arithmetic unit 11 compares the four photometric outputs and selects the lowest one of the four photometric outputs.

The drive section 12 has a rotation angle at which the polarized light component detected by the photometric element having the photometric output selected by the arithmetic section 11 can be removed.
The motor 6 is rotated so that

The rotation of the motor 6 is transmitted via the gear 5 to the gear 4 of the polarizing filter 3 for photographing, and sets the rotating angle of the polarizing filter 3 for photographing to the above-mentioned angle of rotation.

Since this series of operations is performed automatically,
The light incident on the lens 1 is obtained by removing reflected light containing a large amount of polarized light components reflected by glass, a water surface, or the like. The camera 2 records an easy-to-view image in which an image due to the reflected light is removed.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.
1 shows a polarization removing device according to an embodiment. Note that the basic configuration of the polarization elimination device of the present embodiment is the same as that of the polarization elimination device of the first embodiment. Instead of the description.

The polarized light removing apparatus according to the present embodiment comprises a non-polarized beam splitter 11 provided inside a taking lens 100.
By 4, a part of the photographing light is separated and guided to the polarization component photometer.

The first and second polarization component photometers
The configuration described in the embodiment can be applied (the figure shows the polarization component photometer of the first embodiment).

In this embodiment, the polarizing filter 103 for photographing needs to be disposed on the image plane side of the beam splitter 114.

With such a configuration, there is an advantage that parallax between the taking lens 100 and the photometric element 9 can be eliminated.

In this embodiment, the photometric elements 9a to 9
The output from d is amplified by an amplifier 10 and, if necessary, subjected to compression and correction of characteristics, and then input to an arithmetic unit 11. The arithmetic unit 11 compares the four photometric outputs,
The lowest one of these four photometric outputs is selected.

The drive unit 12 controls the motor 6 so that the photographing polarizing filter 103 is oriented at the same rotation angle as the rotation angle of the photometric polarizing filter corresponding to the photometric element having the photometric output selected by the arithmetic unit 11. Rotate.

The rotation of the motor 6 is transmitted via the gear 5 to the gear 4 of the polarizing filter 3 for photographing, and sets the rotating angle of the polarizing filter 3 for photographing to the above-mentioned angle of rotation.

Since this series of operations is performed automatically,
The light incident on the lens 100 is obtained by removing reflected light containing a large amount of polarized light components reflected by glass, a water surface, or the like. The camera 2 records an easy-to-view image in which an image due to the reflected light is removed.

(Fourth Embodiment) FIG. 5 shows a fourth embodiment of the present invention.
2 illustrates a polarization component photometry unit of the polarization removal device according to the embodiment. In the present embodiment, components common to the first embodiment are denoted by the same reference numerals as in the first embodiment, and description thereof will not be repeated.

In each of the above embodiments, the case where the polarization component photometer is configured using a plurality of photometric elements has been described. However, in the present invention, the polarization component photometer is configured using one photometric element.

The polarization component photometer of the present embodiment is composed of a small lens 57, a photometric element 59, and a liquid crystal filter which is disposed between the photometric element 59 and the small lens 57, and whose polarization direction is rotated according to the state of conduction. 66, and a photometric polarizing filter 58 disposed between the liquid crystal filter 66 and the photometric element 59.
It is composed of

The liquid crystal filter 66 is sandwiched between two transparent electrodes 65, and is driven by a liquid crystal driving section 67.
By changing the voltage applied between 65, the polarization direction is periodically rotated.

Of the light that has passed through the liquid crystal filter 66, the light component that has also passed through the photometric polarizing filter 58 is a photometric element 59.
And the photometric element 59 outputs a photometric output according to the incident light.

The output of the light measuring element 59 is
Are sampled together with the information on the polarization direction, and stored in a memory (not shown).

The arithmetic unit 18 extracts the polarization direction of the liquid crystal filter 66 having the lowest photometric output stored in the memory, and sets the rotation angle of the photographing polarization filter 3 in the same manner as in the above-described angular embodiment. I do.

Since this series of operations is performed automatically,
The light incident on the photographing lens 1 is obtained by removing reflected light containing a large amount of polarized light components reflected on glass, a water surface, or the like, and the camera 2 records an easy-to-view image from which an image due to the reflected light has been removed.

In this embodiment, since the polarization components are measured in a time-division manner, a plurality of polarization components cannot be measured at the same time. However, similarly to the above embodiments, the measured image is not affected, It is possible to further reduce the size of the inexpensive polarization removing device with a simple configuration.

Further, since the polarization eliminator of the present embodiment does not use the photographing camera itself for photometric detection as in the prior art, the polarization component to be removed from the photographing light at a higher speed than the field frequency of the camera in a short time. (That is, the rotation angle of the polarizing filter 3 for photography) can be determined.

In the present embodiment, the liquid crystal filter and the
Although a case has been described in which the polarization component photometry unit is configured using one photometry element, a photometric polarization filter that is driven to rotate similarly to the imaging polarization filter 3 may be used instead of the liquid crystal filter.

[0065]

As described above, according to the present invention,
Instead of using the imaging light as it is to determine the polarization component to be removed, light received through a different optical path from the imaging optical path is used to determine the polarization component to be removed from the imaging light. Thus, it is possible to determine a polarization component to be removed without affecting a captured image, and to realize a polarization elimination device that can be applied to a simple and inexpensive configuration in which a polarization filter for imaging is rotated by a motor or the like.

Further, according to the present invention, since a configuration without using a liquid crystal can be adopted, a polarization removing device which is hardly affected by a temperature change can be provided.

Further, as a filter setting means, a plurality of polarization components included in the light received through the different optical path are respectively photometrically detected, and a polarization component having the lowest photometric result among the plurality of polarization components is detected by a photographing polarization filter. In the case where the polarization component to be removed is determined, if a plurality of photometric elements having sensitivity to polarization components having different polarization directions are used and each polarization component is measured at the same time, the subject and the lighting state Can be determined without being affected by the change in.

The operability can be improved by making this polarization removing device detachable from the photographing device and mounting it on the photographing device only when necessary.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an imaging system according to a first embodiment of the present invention.

FIG. 2 is a front view showing the configuration of a polarization component photometry unit of the polarization elimination device included in the imaging system.

FIG. 3 is a perspective view illustrating a configuration of a polarization component photometry unit of a polarization elimination device according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of an imaging system according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of an imaging system according to a fourth embodiment of the present invention.

[Description of Signs] 1,100 photographing lens 2 camera 3, 103 photographing polarizing filter 6 motor 7 (7a to 7d), 27a, 27b, 57 small lens 8 (8a to 8d), 58 photometric polarizing filter 9 (9a) To 9d), 29a to 29d, 59 Photometric element 10 Amplifier 11 Operation unit 12 Drive unit 33a, 33b Polarization beam splitter 65 Transparent electrode 66 Liquid crystal filter 67 Liquid crystal drive unit 114 Non-polarization beam splitter

Claims (13)

[Claims] 1. A photographing polarizing filter for removing a polarized component in a specific polarization direction from light incident on a photographing optical path, and a polarizing component to be removed by the photographing polarizing filter is determined to operate the photographing polarizing filter. A polarization setting device, comprising: a filter setting unit, wherein the filter setting unit removes the polarization component to be removed by the imaging polarization filter based on a detection result of a polarization component included in light received through another optical path different from the imaging optical path. A polarization elimination device. 2. The polarization eliminator according to claim 1, wherein the filter setting unit has a dedicated optical path juxtaposed to the photographing optical path. 3. The depolarization apparatus according to claim 1, wherein the filter setting unit has an optical path that enters the photographing optical path and receives light separated from the photographing light in the photographing optical path. apparatus. 4. The photographing polarization filter is capable of changing a polarization component to be removed in accordance with a rotational position, and the filter setting unit is configured to:
4. The polarization elimination apparatus according to claim 1, wherein the polarization elimination device is driven to a rotation position corresponding to a result of determining a polarization component to be eliminated by the imaging polarization filter. 5. The filter setting means for photometrically detecting a plurality of polarization components included in the light received through the another optical path, and determining a polarization component having the lowest photometric result among the plurality of polarization components for the photographing. The polarization elimination device according to any one of claims 1 to 4, wherein the polarization component is determined as a polarization component to be eliminated by the polarization filter. 6. The polarization eliminator according to claim 5, wherein the filter setting unit is configured using a plurality of photometric units having sensitivity to light having different polarization directions. 7. The plurality of photometric devices include a plurality of photometric devices, and a plurality of photometric polarizing filters on an incident surface side of the plurality of photometric devices for removing polarized components having polarization directions different from each other. The polarization removing device according to claim 6, wherein the device is configured. 8. The polarization removing apparatus according to claim 6, wherein the filter setting unit includes a light splitting unit that splits the received light into a plurality of polarization components and makes the light incident on the plurality of photometric units. . 9. The filter setting means includes: a photometric polarizing filter whose polarization component to be removed changes according to a rotational position; and a photometric means for photometrically detecting light passing through the photometric polarizing filter. The polarization component to be removed by the photographing polarization filter is determined based on the rotational position of the photometry polarization filter at which the photometry result by the photometry unit becomes the lowest. A polarization eliminator according to any one of the above. 10. The filter setting means includes: a liquid crystal filter in which the direction of a polarization component to be removed changes according to an energized state; and photometric means for photometrically detecting light passing through the liquid crystal filter. And a polarization component to be removed by the photographing polarization filter is determined based on a state of the liquid crystal filter at which a photometry result obtained by the photometry unit becomes lowest.
5. The polarization removing device according to any one of items 1 to 4. 11. The polarization removing apparatus according to claim 1, wherein a photometric angle of view of the plurality of polarization components in the filter setting unit is narrower than a shooting angle of view. 12. The polarization elimination device according to claim 1, wherein the polarization elimination device is detachable from an imaging device. 13. An imaging system, comprising: the polarization elimination device according to claim 1; and an imaging device that performs imaging through the polarization elimination device.