JPH066334Y2 - Diffuse reflection shielding device for in-tube camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention relates to a diffuse reflection shielding device for a camera for photographing inside a tube that photographs the inner wall of the tube from the side.

(Prior Art) There is a pipe photographing camera capable of photographing the inside of a pipe through which a telephone cable or the like is passed or water and sewer pipes.

The conventional in-tube camera is designed to insert a TV camera into the tube and observe the inside of the tube while looking at the external monitor.In addition, the TV camera and the still camera are combined to see the monitor connected to the TV camera. However, it is designed to shoot with a still camera as needed. In any case, since the inside of the tube is dark, an illuminating device for illuminating the part to be photographed is required.

(Problems to be solved by the invention) A television camera is used as a conventional camera for photographing inside a tube,
Also, with some types of in-camera cameras, multiple illumination light sources are arranged around the camera, or the illumination light sources are arranged so as to rotate integrally with the camera, resulting in a large camera body and a large diameter. You can only take pictures inside the tube. Further, in another type of camera for photographing inside a tube, an obliquely arranged mirror is used to bend the photographing lens optical axis of the camera to the side so as to photograph the inner peripheral surface of the tube, and an illumination light source is provided on the back side of the mirror. Is arranged so that the illumination light does not directly enter the photographing lens, but such an in-tube camera has a long overall length and cannot be used for a bent tube.

An effective means for downsizing the camera body and making it possible to shoot inside a tube with a smaller diameter and inside a curved tube is to use a still camera as the camera built into the camera body, but there are various ways to make the camera a thrull camera. There are design restrictions. First of all, a strobe light emitter is an effective illumination light source when using a still camera, but if the illumination light is effectively used and the camera body is made as small as possible, the installation position of the strobe light emitter is It is limited to the side of the taking lens of the camera. Also, if you want to shoot the inner wall surface of the tube as a subject accurately and over the entire circumference, aim the optical axis of the camera's shooting lens toward the central axis of the camera body, and then tilt the mirror on this optical axis. And bend the lens optical axis to the side,
It is necessary to be able to rotate the mirror in the range of 360 ° so that the photographing range of the photographing lens can be converted in the range of 360 °. On the other hand, the camera body must be hermetically sealed so that water, earth and sand, etc. do not enter inside, and the illumination light from the strobe light emitter reflected by the mirror is transmitted to the outside of the camera body. In addition, a transparent tube for transmitting the reflected light from the inner wall of the tube as the subject toward the mirror is required.

However, when the mirror and the transparent tube as described above are provided, and the stroboscopic light emitting device is provided on the side of the photographing lens, the illumination light from the stroboscopic light emitting device is reflected by the transparent tube or the mirror and enters the photographing lens, The light emission part of the strobe light is reflected on the film, which is not practical.

The above-mentioned problems have been found in the trial production stage of the camera according to the present invention. In other words, in the prototype camera that does not have a transparent tube that seals the camera body, the light emission part of the strobe light emitter was not reflected in the film, but in the prototype with the transparent tube, there are white and small white dots scattered. I confirmed that it was reflected. It could not be predicted at all because there is no indication of such a problem in the literature of similar cameras. However, since the prototype that did not show the spots does not have a transparent tube, and the spots are similar to the shape of the light emitting part of the strobe light emitter, the spots are reflected in the strobe light reflected by the transparent tube. As a result of analyzing the reflection path of the stroboscopic light on the drawing, the spots are caused by the reflected light that the stroboscopic light is composed of an indefinite number of reflection paths in the oblique mirror and the transparent tube. It was found that there are innumerable reflection paths for one rotation of the mirror.

Therefore, a measure was proposed and examined. The results are as follows.

A) Use a transparent tube with anti-reflection.

We thought about using an anti-reflection film on a transparent tube or using a coating technology that is used to improve the transparency.In the former case, the transparency of the transparent tube is significantly impaired, and in the latter case, it is not applicable to the inner surface of the cylinder. It turned out to be difficult.

B) Use a deflection filter.

A commercially available deflection filter was set on the camera, and illumination light was applied from the side of the camera to a plate glass as a reflecting surface in front of the camera, and the effect of preventing reflected light from entering was examined, but no effect was observed.

C) Irradiate the inside of the tube directly without passing through the transparent tube.

The front of the camera body near the transparent cylinder and the outer periphery of the rear were equipped with strobes toward the inner wall of the tube for shooting. Although the effect of preventing the reflection of the spots was recognized, with a camera intended to shoot a small-diameter tube, a small separation distance can be taken between the strobe emission surface and the inner wall surface of the tube, and the illumination light I found that I could not reach the shooting range. Further, it is disadvantageous to provide the above-mentioned illumination means for a camera for photographing inside a tube which is required to have a small diameter and a short length.

Based on the above results, we abandoned radical deletion of spots, and reexamined with the goal of eliminating spots to the extent that there is no practical problem.

First, we decided to find the dimensional area where the reflected light did not enter the taking lens by changing the mutual distance between the strobe light emitting part, the mirror, the transparent tube, and the taking lens, and adjusting the light reflection path. However, the in-tube camera has a dimensional restriction, and the effect is not recognized even if the size is slightly changed.

Next, we considered the effect of changing the tilt angle of the mirror, which was initially unthinkable because of concern about distortion of the shooting screen. As a result, it was found that the incident pattern of the reflected light changes significantly with the change of the tilt angle of the mirror.Furthermore, in the subsequent study, there is a region where the reflected light does not enter due to the rotation angle of the mirror, and the tilt angle changes. Found that of the light emitted from the strobe light emitter, only light traveling in one direction is incident. Here, the idea of blocking the illumination light traveling in one direction came up.

Therefore, an object of the present invention is to have a stroboscopic light emitter for illumination on the side of the taking lens of the still camera, an oblique mirror for side view in the camera body, and a transparent tube for sealing the camera body. In the in-tube camera, the illumination light from the strobe light emitter is diffusely reflected by the oblique mirror of the transparent tube and a shielding member is provided in the path to the shooting lens, so that the light emitting portion of the strobe light emitter is provided on the shooting film. An object of the present invention is to provide a diffuse reflection shielding device that prevents reflection.

(Means for Solving Problems) A diffuse reflection shielding device for a camera for photographing in a tube according to the present invention includes a camera body that can be inserted into a tube as a subject, and an optical axis of a photographing lens in the camera body. A still camera mounted in the direction of the central axis of the main body, and a strobe light emitting device having a light emitting portion provided on the side of the photographing lens,
The optical axis of the photographing lens and the illumination light from the stroboscopic light emitter are obliquely provided on the optical axis of the photographing lens so as to be bent sideways,
Moreover, the mirror provided rotatably around the optical axis of the taking lens and the illumination light from the stroboscopic light emitter reflected by this mirror are transmitted toward the inner wall of the tube as the subject, and are transmitted from the inner wall of the tube. It has a transparent cylinder that transmits reflected light and guides it to a mirror, and a shielding member that is integrally provided on the mirror, and this shielding member is provided with a light input / output side with respect to the inner wall surface of the tube to be photographed. Is formed in a partially cylindrical shape along the rear edge of the mirror on the opposite side, is extended in the optical axis direction of the taking lens, is outside the photographing range of the taking lens, and is from the strobe light emitter. The illumination light is diffusely reflected by the mirror or the transparent cylinder and is on the path of entering the photographing lens.

(Operation) Illumination light from the stroboscopic light emitter is reflected to the side by the mirror, then passes through the transparent tube, and is irradiated to the inner wall of the tube as the subject to illuminate it. The light reflected from the inner wall of the tube passes through the transparent cylinder, is then reflected by the mirror and is guided to the taking lens, and the image of the inner wall of the tube is imaged on the film by the taking lens. Since the shielding member integrally formed on the rear edge of the mirror is outside the photographing range of the photographing lens, it does not hinder photographing of the inner wall of the tube. Further, since the shielding member is provided in the path where the illumination light from the stroboscopic light emitter is diffusely reflected by the mirror or the transparent tube and enters the photographing lens, the light emitting portion of the stroboscopic light emitter is not reflected on the film. Absent.

(Embodiment) In FIG. 1, reference numeral 1 denotes a camera body which has a cylindrical outer shape and can be inserted into a tube as a subject. The camera body 1 is roughly divided into a base 2, a transparent cylinder 3 connected to the base 2, and a protective cap 4 covering the tip of the transparent cylinder 3. A still camera is provided on the base 2 with the optical axis of the taking lens 6 thereof directed toward the central axis of the camera body 1. In front of the taking lens 6, a converter lens 8 for taking an image of the inner wall of the tube as a subject at a close position is provided.

The transparent cylinder 3 has a transparent cylindrical shape over the entire circumference.
The transparent tube 3 is held by the tube body 10 held by the support columns 9 standing on the base body 2 and the base body 2.
The protective cap 4 is screwed onto the cylindrical body 10 so as to cover the tip of the transparent cylinder 3. Cylinder 10
Has a bottomed cylindrical shape, and a geared motor 13 is attached to a central portion of a bottom portion 11 thereof via a holder 12.
A boss 15 is attached to the output shaft 14 of the motor 13. The boss 15 penetrates the bottom portion 11 of the cylindrical body 10 in the direction of the central axis of the camera body 1, and a mirror 16 is attached to the boss 15. The mirror 16 is obliquely installed at a certain angle with respect to the optical axis of the taking lens 6. The mirror 16 is driven by a motor 13 to drive the taking lens 6 in the space surrounded by the transparent tube 3.
The optical axis of the photographing lens 6 and the irradiation range of the illumination light from the light emitting portion 7 of the stroboscopic light emitter can be rotated within a range of 360 °.

In FIG. 1, reference numeral 20 indicates the inner wall of the tube as a subject. If the edge of the oblique mirror 16 closer to the taking lens 6 is the trailing edge and the edge closer to the protective cap 4 is the leading edge, the light to the inner wall surface of the tube to be photographed is defined. At the rear edge of the mirror 16 on the side opposite to the entrance / exit side, a partially cylindrical shield member 18 is provided in the optical axis direction of the taking lens 6 as shown in FIG. It is provided integrally with the mirror 16 so as to face the lens 6. The inner peripheral surface of the shielding member 18 is subjected to antireflection treatment by means such as sticking black flocked paper.

Now, when the illumination light is emitted from the light emitting portion 7 of the strobe light emitting device in synchronization with the operation of the shutter of the camera, the illumination light is reflected to the side by the mirror 16 and then transmitted through the transparent tube 3 to be a subject 20. The inner wall of the tube is irradiated and this is irradiated. Further, the light reflected from the inner wall of the tube is transmitted through the transparent tube 3 and then reflected by the mirror 16 to enter the photographing lens 6, and the image forming function of the lens 6 causes the image of the inner wall of the tube to be imaged on the loading film.

The camera body 1 having the above-described structure is provided with a control box 23 via a cable 22 as shown in FIG.
Are linked to. The control box 23 includes a main switch 24, an operation switch 25, a shooting preparation display lamp 26,
It has a film counter 27 and the like. The camera body 1
The inner wall of the tube is photographed by being inserted into the tube to be photographed and remotely controlled by the control box 23. Since the remote control device is not directly related to the present invention, its explanation is omitted.

In FIG. 1, a shield member 18 provided at the rear edge of the mirror 16 is supposed to make the illumination light from the light emitting section 7 of the stroboscopic light emitter diffusely reflected by the mirror 16 and the transparent tube 3 and enter the taking lens 6 of the camera. Is provided in the diffused reflection path of the light. The shielding member 18 is provided outside the photographing range of the photographing lens 6.

Under the condition that the light emitting portion 7 of the strobe light emitting device is provided on the side of the photographing lens 6 and the side-view mirror 16 is obliquely provided, the shielding member 18 is effective for the diffused reflected light of the illumination light from the strobe light emitting device. Can be shielded against
In order to satisfy the condition that 18 is out of the photographing range of the photographing lens 6, it is necessary to consider the design value of the camera body 1, especially the oblique angle of the mirror 16. FIG. 4 and subsequent drawings are explanatory views for obtaining preferable design values of the camera body.

Now, the dimensional relationship of each part is set as shown in FIG. 4, and the mirror 16 with respect to the optical axis of the taking lens 6 is set.
The inclination angle of is 30 °. In FIG. 4, reference numeral 30 is a photographic film loaded in the camera body 1. The mirror 16 is placed around the optical axis of the taking lens 6 as shown in FIG.
Although it can be rotated in the range of 360 °, the mirror 16 is fixed in FIG. 4 and, instead, the light emitting portion 7 of the stroboscopic light emitter is shown as being rotatable in the range of 360 °.
A, B, and C in FIG. 4 indicate the rotational positions of the light emitting unit 7, respectively. As is apparent from FIG. 4, when the mirror 16 is set at an angle of 30 °, the light emitted from the light emitting unit 7 when the light emitting unit 7 is in the range Z1 from B to C with respect to the mirror 16. The light is reflected in the order of the transparent cylinder 3-mirror 16-transparent cylinder 3-mirror 16 and enters the taking lens 6, and the image of the light emitting unit 7 is reflected on the film 30.

In FIG. 5, the dimensional relationship of each part is the same as in FIG.
This is the case when the inclination angle of is set to 45 °. In this case as well, the illumination light from the light emitting unit 7 is reflected in the order of the transparent tube 3-mirror 16-transparent tube 3-mirror 16, and the illumination light from the light emitting unit 7 is ordered in the order of mirror 16-transparent tube 3-mirror 16. The reflected light enters the taking lens 6 and the image of the light emitting portion 7 is reflected on the film 30. The range of the relative position of the light emitting unit 7 in which the image of the light emitting unit 7 is reflected on the film 30 extends over the entire range Z2.

In FIG. 6, the dimensional relationship of each part is the same as in FIG.
This is the case when the inclination angle of is set to 53.5 °. In this case, when the light emitter 7 is at the relative position B, the illumination light emitted from a part of the range Z3 of the light emitter 7 is reflected by one surface of the transparent tube 3 facing each other and then the mirror 16 There is a possibility that the light will be reflected by the first lens, the light will be reflected by the other surface of the transparent cylinder 3, and then the light will be reflected by the mirror 16 and enter the photographing lens 6. However, since the illumination light emitted from the light emitting unit 7 tries to travel toward one of the opposite surfaces of the transparent tube 3, the above-mentioned shielding member 18 exists in the irregular reflection path, so that the irregular reflection path is generated by the shielding member 18. It is blocked so that the image of the light emitting portion 7 is prevented from being reflected on the film 30. In addition, the light emitting unit 7 is located at the relative position A,
If it is located at a position other than B and C, the irregular reflection path formed by the transparent cylinder 3-mirror 16 and the mirror 16-transparent cylinder 3-mirror 16
There is a possibility that the illumination light of the light emitting section 7 may enter the photographing lens 6 through the irregular reflection path consisting of or the irregular reflection path consisting of the transparent cylinder 3-mirror 16-transparent cylinder 3-mirror 16. There is a possibility that it will be reflected and incident on the taking lens 6, but the relative movement range of the light emitting section 7 is A, B, C.
There is no problem because it is limited to the position.

Incidentally, in the case of FIGS. 4 and 5, even if the shield member 18 is integrally provided at the rear edge portion of the mirror 16, the irregular reflection path by the transparent tube 3 or the like cannot be shielded.

In this way, if the tilt angle of the mirror 16 is set to about 53.5 °, the diffused light can be effectively prevented from entering the taking lens 6 in combination with the provision of the shield member 18 at the rear edge of the mirror 16. Therefore, it is possible to prevent the image of the light emitting unit 7 from being reflected on the film 30.

Here, even if there is an inclination angle of the mirror 16 effective for preventing irregular reflection by the mirror 16 and the transparent tube 3, the angle is
Whether the angle is appropriate for shooting the inner wall of the tube as a subject, that is, whether there is little distortion in the captured image and it is possible to shoot at approximately the same size in the entire range, and to try to imprint Depending on the range of subjects to be used, the flash unit 7
It is necessary to consider whether or not it is an angle that can effectively irradiate the illumination light from.

7 to 9 show the relationship between the photographing range and the irradiation range of the illumination light with respect to the tilt angle of the mirror 16, and the range indicated by the alternate long and short dash line a indicates that the light emitting unit 7 of the strobe light emitter is The irradiation range of the illumination light at the position A, the range indicated by the two-dot chain line b is the irradiation range of the illumination light when the light emitting unit 7 is at the position B, and the range indicated by the chain line c is Illumination range of the illumination light when the light emitting unit 7 is at the position C, solid line d
The ranges indicated by are the ranges in which the inner wall of the tube as the subject is reflected.

FIG. 7 shows the case where the tilt angle of the mirror 16 is 30 °.
In this case, both the range where the subject is reflected and the illumination range by the light emitting unit 7 are shifted forward, but the range of the subject 20 which is reflected on the film 30 is limited because the length of the transparent tube 3 is limited. That is, only a limited range of the subject 20 is reflected on a part of the screen of the film 30. Moreover, when the light emitting unit 7 is at the position C, the illumination range c by the light emitting unit 7 is
Can cover only a part of the photographing range of the photographing lens 6.

FIG. 8 shows the case where the tilt angle of the mirror 16 is 45 °.
In this case, the shooting range d by the shooting lens 6 and the illumination ranges a and b when the light emitting unit 7 of the strobe light emitter is at the position A or B are substantially the same, and when the light emitting unit 7 is at the position C. The illumination range c deviates from the photographing range d to some extent, but this does not cause much trouble.

FIG. 9 shows the case where the tilt angle of the mirror 16 is 53.5 °. In this case, the shooting range d by the shooting lens 6 and the lighting range a and c when the light emitting unit 7 is at the position A or C are substantially the same, and the lighting range b when the light emitting unit 7 is at the position B is Although it is slightly deviated from the shooting range d, the shooting range itself is a relatively wide range, so that it does not cause much trouble.

As described above, in the case of the illustrated embodiment, the diffuse reflection shielding effect by providing the shielding member 18, and whether the captured image has little distortion and the entire range is approximately the same size and the illumination range by the strobe light emitter are set. From a comprehensive judgment, it is preferable that the tilt angle of the mirror 16 be about 53.5 °.

However, the preferable tilt angle of the mirror 16 varies depending on the dimensional relationship of each part of the camera body, the focal length of the photographing lens and other conditions, and should not be uniformly determined.

(Effect of the Invention) According to the present invention, a strobe light emitter for illumination is provided on the side of a photographing lens of a camera, and the optical axis of the photographing lens and illumination light from the strobe light emitter are bent sideways in the camera body. In an in-tube shooting camera having a slanting mirror for the purpose and having a transparent tube that is transparent over the entire circumference and seals the camera body, on the side opposite to the light entrance / exit side with respect to the inner wall surface of the tube to be shot. By integrally forming a partially cylindrical shielding member along the rear edge of the oblique mirror,
The illumination light from the strobe light emitter is diffusely reflected by the mirror and the transparent tube to block the path that is going to enter the shooting lens, effectively preventing the light emission part of the strobe light emitter from being reflected in the shooting lens. It is possible to obtain a clear image of the inner wall surface of the tube.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is an external view showing an example of a camera for photographing inside a tube having the device of the present invention and its control box, and FIG. 3 is used in the above embodiment. 4 is a front view of the mirror, FIG. 4 is an optical path diagram showing an example of the irregular reflection path in the above embodiment, FIG. 5 is an optical path diagram showing another example of the irregular reflection path, and FIG. FIG. 7 is an optical path diagram showing an example, and FIG. 7 is an optical path diagram showing an example of a shooting range and an illumination range in the above embodiment.
The figure is an optical path diagram showing another example of the photographing range and the illumination range, and FIG. 9 is an optical path diagram showing the still another example of the photographing range and the illumination range. 1 ... camera body, 3 ... transparent tube, 6 ... shooting lens,
7 ... Light emitting part, 16 ... Mirror, 18 ... Shielding member, 20 ...
subject.

Claims (1)

[Scope of utility model registration request] 1. A camera main body made to be insertable into a tube as a subject, a still camera mounted in the camera main body with an optical axis of a photographing lens directed toward a central axis of the camera main body, and a light emitting section. A stroboscopic light emitting device provided on the side of the taking lens, and an optical axis of the taking lens and the optical axis of the taking lens so as to bend the illumination light from the stroboscopic light emitting device to the side, and A mirror that is rotatable around the optical axis of the lens and the illumination light from the strobe light emitter reflected by this mirror are transmitted toward the inner wall of the tube as the subject, and the reflected light from the inner wall of the tube is transmitted. A transparent tube that is transparent all around and leads to the mirror.
And a shield member provided integrally with the mirror, the shield member extending along the rear edge of the mirror opposite to the light entrance / exit side with respect to the inner wall surface of the tube to be photographed. Is formed in a partially cylindrical shape and is extended in the optical axis direction of the photographing lens to be outside the photographing range of the photographing lens, and the illumination light from the strobe light emitter is diffusely reflected by the mirror and the transparent cylinder. An irregular reflection shielding device for a camera for photographing inside a tube, which is in a path to be incident on a photographing lens.