JP2012230048A - Imaging apparatus and internal observation method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To observe an observation object part inside an internal space forming body at a plurality of magnifications, and insert an imaging device in the interior of the internal space forming body from a narrow inspection hole.SOLUTION: An imaging device 30 includes a varifocal optical system 41. The varifocal optical system includes a plurality of lens bodies 45a, 45b, 45c, and 45d disposed serially. Each lens body has one or a plurality of lenses 12 in which laser light passes, and holding/moving pieces 47a, 47b, 47c and 47d for holding the lenses and being movable in the optical axis direction. Actuators 53a, 53b, and 53c are disposed in the plurality of holding/moving pieces 47a, 47b, and 47c respectively. An imaging magnification can be adjusted by moving the holding/moving pieces in the optical axis direction. Drive force transmitting portions 47a1, 47b1, and 47c1 of the respective holding/moving pieces are mutually deflected in the circumferential direction around an optical axis. The mutual actuators are superposed on the corresponding drive force transmitting portions in the optical axis direction.

Description

  The present invention includes a box that is inserted into the internal space from a hole provided in a wall of an internal space forming body having an internal space, and an observation object in the internal space from a viewing window provided in the box The present invention relates to an imaging device that images a section. The present invention also relates to an internal observation method using an imaging apparatus.

  In this application, the internal space formation body should just be what has internal space (for example, container) as well as furnaces, such as a hot blast furnace and a high temperature furnace of a boiler which supply a hot blast to a steelmaking blast furnace.

  In order to observe the observation target part in the internal space forming body, the observation target part is imaged by an imaging device. Hereinafter, a case where the internal space forming body is a furnace will be described.

  The hot stove has a height of about 50 m above the ground and an inner diameter of 10 m or more, and the inner wall temperature reaches 1100 ° C. or more (for example, about 1600 ° C. during operation and about 1400 ° C. during rest). Moreover, since this hot stove is a large facility, the construction period is as long as about 3 years, and after completion, it is continuously operated over a long period of about 20 years. Therefore, if even one unit becomes unusable, it will be forced to stop the operation for a long period of time. Therefore, it is important to perform maintenance in the furnace periodically. As one of the means, observation in the furnace for monitoring the damage state of the furnace wall has been performed for a long time.

  As an in-furnace observation method, there is already a method for measuring the degree of damage by imaging a furnace wall with an imaging device such as a CCD (Charge Coupled Device) camera and performing image processing or the like. In this method, the laser beam is irradiated onto the furnace wall by the laser projector, and the furnace wall irradiated with the laser beam is imaged by the imaging device. Note that the laser projector and the imaging device are accommodated in one box, and the laser beam is irradiated from a projection window formed in the box.

  The in-furnace observation method as described above is described in Patent Document 1 below, for example.

JP 2010-133950 A Japanese Patent Laid-Open No. 07-113942

  However, conventionally, the imaging apparatus has no function of imaging an observation target part such as an observation target part (for example, the furnace wall in the furnace described above) in the internal space formation body at a plurality of magnifications. For example, the imaging device did not have a function of imaging the observation target part at both 1 × and 5 ×.

  Therefore, the observation target part could not be observed in detail. Although important information may be obtained by taking a close-up image of a necessary observation target part, such an image could not be obtained.

  In contrast, conventional varifocal optical systems of conventional cameras are provided with a focus adjustment mechanism, a focal length change mechanism, etc. on the outer periphery of the lens as follows in order to reduce the dimension in the optical axis direction. ing. A holding and moving piece for holding the lens is attached to the outer periphery of each lens of the varifocal optical system. The holding and moving piece can move along with the lens in the optical axis direction of the varifocal optical system. A driving device (such as a focus adjustment mechanism or a focal length changing mechanism) for driving the holding and moving piece is provided outside the holding and moving piece in the radial direction with respect to the optical axis (for example, Patent Document 2).

As a result, the outer diameter of the varifocal optical system including the focus adjusting mechanism and the focal length changing mechanism is about 50 mm even if the effective lens diameter of the varifocal optical system is about 10 mm.
Therefore, it is difficult to insert the box containing the optical system configuration having such dimensions into the internal space forming body through the narrow inspection hole formed in the internal space forming body (for example, the furnace wall).

  Therefore, an object of the present invention is to enable observation of the observation target portion inside the internal space formation body (for example, a furnace) at a plurality of magnifications, and to insert the box body from the narrow inspection hole into the internal space formation body. There is to do.

In order to achieve the above object, according to the present invention, there is provided a box body that is inserted into an internal space forming body through a hole provided in a wall of an internal space forming body having an internal space, and a peep provided in the box body. An imaging device that images an observation target portion inside an internal space formation body from a window,
An image sensor provided inside the box and generating image data based on light received from the observation target part;
A varifocal optical system that is provided inside the box and forms an observation target portion on the light receiving surface of the imaging device;
The varifocal optical system has a plurality of lens bodies arranged in series, and each lens body includes one or a plurality of lenses through which light from an observation target portion passes, and the one or a plurality of lenses. Holding and moving piece that is movable and movable in the optical axis direction of the varifocal optical system,
At least two of the holding and moving pieces are holding and moving pieces that can move independently of each other in the optical axis direction of the varifocal optical system,
The imaging magnification of the observation target portion on the light receiving surface by the varifocal optical system is adjusted by moving the at least two holding and moving pieces in the optical axis direction independently of each other provided in the box. A drive device for
The drive device
An actuator that is provided for each of the at least two holding and moving pieces, and that drives the corresponding holding and moving pieces in the optical axis direction of the varifocal optical system;
The driving force transmitting portions that receive driving force from the corresponding actuators in the at least two holding moving pieces are arranged so as to be shifted from each other in the circumferential direction around the optical axis of the varifocal optical system. An imaging apparatus is provided, which is disposed so as to overlap with the corresponding driving force transmission portion when viewed from the axial direction.

According to a preferred embodiment of the present invention, a position sensor provided for each of the at least two holding and moving pieces, and detecting a position of the corresponding holding and moving piece;
For each of the at least two holding and moving pieces, a control device that moves the holding and moving piece to a predetermined set position by controlling an actuator based on the detected position of the holding and moving piece, and
In a state where the box is inserted from the hole into the internal space formation body, a plurality of the imaging magnifications are predetermined with respect to a known distance from the varifocal optical system to the observation target portion inside the internal space formation body. And
For each imaging magnification, the position of each holding and moving piece for obtaining the imaging magnification is obtained in advance as the set position and stored in the storage unit of the control device.

According to a preferred embodiment of the present invention, the driving device comprises:
A guide mechanism for engaging the holding and moving piece so as to guide the at least two holding and moving pieces in the optical axis direction;
A screw shaft provided for each of the at least two holding and moving pieces, extending in the optical axis direction, and screwed into the corresponding holding and moving piece;
Each actuator is a motor that moves the corresponding holding moving piece in the optical axis direction by guiding the guide mechanism by rotating the corresponding screw shaft.

Further, according to a preferred embodiment of the present invention, a lens barrel that is provided in the box and accommodates each lens therein is provided.
A plurality of elongated holes extending in the axial direction are formed on the side wall of the barrel,
Each of the plurality of elongated holes is formed as the guide mechanism that engages with the at least two holding and moving pieces.

  According to a preferred embodiment of the present invention, each of the at least two holding and moving pieces is coupled to the lens body in the lens barrel, and extends from the lens barrel to the outside of the lens barrel through the elongated hole. And screwed with the screw shaft outside the lens barrel.

According to a preferred embodiment of the present invention, a display for displaying the image data;
A command device capable of controlling the actuators independently of each other by being operated by a person.

In order to achieve the above object, according to the present invention, there is provided an internal observation method using the above-described imaging device,
(A) inserting the box into the internal space forming body,
(B) The observation target part is imaged by an imaging device and displayed on a display;
(C) An internal observation method is provided, wherein the position of the lens body is adjusted so that the displayed observation target portion is imaged on a light receiving surface of the imaging device.

According to the present invention, by adjusting the position of each holding and moving piece of the varifocal optical system, the imaging magnification can be adjusted while the observation target part is imaged on the light receiving surface of the image sensor.
The driving force transmitting portions that receive driving force from the corresponding actuators in the at least two holding moving pieces are arranged so as to be shifted from each other in the circumferential direction around the optical axis of the varifocal optical system. Since it arrange | positions so that it may overlap with the said corresponding driving force transmission part seeing from an axial direction, the internal diameter of a box can be restrained small. Therefore, the box can be inserted into the inner space forming body through the narrow inspection hole.
Therefore, the observation target portion inside the internal space forming body can be observed at a plurality of magnifications, and the box can be inserted into the internal space forming body through a narrow inspection hole.

1 shows an internal observation device according to an embodiment of the present invention. The laser projector provided in an internal observation apparatus is shown. It is another figure which shows a laser projector. It is a flowchart which shows the control setting and control method with respect to a laser projector. The relationship between the image formation size of a laser beam and the position of each holding | maintenance moving piece is shown. It is a block diagram which shows the control system of an actuator. 1 illustrates an imaging device according to an embodiment of the present invention. It is another figure which shows the imaging device by embodiment of this invention. It is another figure which shows the imaging device by embodiment of this invention. It is a perspective view which shows the lens-barrel of an imaging device. 3 is a flowchart illustrating control settings and a control method for an imaging apparatus. The relationship between the magnification (light receiving surface side focal length) of the imaging device and the position of each holding moving piece is shown. The image obtained by this invention and the image obtained by the comparative example are shown.

  A preferred embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 1 is a schematic diagram of an internal observation device 10 including an imaging device 30 according to an embodiment of the present invention.
The internal observation device 10 includes a laser projector 20 and an imaging device 30. In the present embodiment, the imaging device 30 captures an image of the observation target portion R irradiated with the laser light from the laser projector 20. In addition, in FIG. 1, the code | symbol 3b shows the furnace wall which divides the inside 3a and the outside of a furnace.
Hereinafter, the laser projector 20 and the imaging device 30 will be described in this order.

[Laser projector]
2 and 3 show the laser projector 20. FIG. 2A is a partially enlarged view of the internal observation device 10 in FIG. 1 and shows the laser projector 20. 2B is a cross-sectional view taken along arrow 2B-2B in FIG. 2C is a view taken in the direction of the arrow 2C-2C in FIG. 2B, and is a view seen through the inside of the box. Note that FIG. 2A is also a cross-sectional view taken along the arrow 2A-2A in FIG.
3A is a cross-sectional view taken along the arrow 3A-3A in FIG. 2A, and FIG. 3B is a cross-sectional view taken along the 3B-3B arrow in FIG. In FIG. 3A, illustration of a holding and moving piece 13a, which will be described later, in particular, a screwed portion with the screw shaft 17a in the holding and moving piece 13a is omitted. In FIG. 3 (B), the holding and moving pieces 13a and 13b, which will be described later, in particular, the screwed portions of the holding and moving pieces 13a and 13b with the screw shafts 17a and 17b are not shown.
3C is a view taken in the direction of arrows 3C-3C of FIG. 3B, and is a view seen through the inside of the box 5. FIG.

  The laser projector 20 is configured to project laser light into the interior 3a of the furnace 3 and to adjust the imaging position and imaging size of the laser light inside the furnace.

  The laser projector 20 includes a box 5, a varifocal optical system 7, and a drive device 9.

  As shown in FIG. 1, the box 5 is inserted into the furnace 3a through a narrow hole 3c provided in the furnace wall 3b. The box 5 has a light projection window 5a through which the laser light that has passed through the varifocal optical system 7 passes from the inside of the box 5 to the furnace 3a. The light projection window 5a is made of, for example, a quartz plate. The box 5 is preferably cylindrical, but may have other shapes.

The box 5 is preferably a water-cooled cylinder in which cooling water flows in the outer peripheral wall thereof. Preferably, cooling air is supplied into the box 5 so that the pressure in the box 5 is higher than the pressure in the furnace 3a, and the surroundings of the light projection window 5a and the observation window 5b described later, vent holes, etc. The air is discharged into the furnace 3a.
With such a configuration, the temperature rise in the box 5 can be suppressed.

  The varifocal optical system 7 is provided inside the box 5 and can adjust the focal length, and is adjusted so that the focus is adjusted each time the focal length (the laser irradiation range at the observation target portion R) is changed. It is. The varifocal optical system 7 has a plurality of lens bodies 11a, 11b, and 11c arranged in series in the optical axis direction so that the laser light passes therethrough.

Each of the lens bodies 11a, 11b, and 11c holds one or more lenses 12 through which the laser light passes, and holds the one or more lenses 12, and is movable in the optical axis direction of the varifocal optical system 7. Holding and moving pieces 13a, 13b, 13c.
The lens 12 is a biconvex lens, a planoconvex lens, a convex meniscus lens, a concave meniscus lens, a planoconcave lens, or a biconcave lens.

  In this example, the laser light is generated by a laser light source (not shown) provided outside the box 5 and is introduced into the varifocal optical system 7 from the end face 8 a of the optical fiber 8 through the optical fiber 8. The An end face 8 a of the optical fiber 8 is imaged on the observation target portion R by the varifocal optical system 7.

  The driving device 9 is provided inside the box 5 and moves a plurality of lens bodies 11a, 11b, and 11c in the optical axis direction independently of each other, so that the laser on the upstream side of the varifocal optical system 7 is provided. The imaging size (laser beam irradiation range) can be adjusted while imaging light (end surface 8a of the optical fiber 8) on the observation target portion R on the furnace interior 3a side. The varifocal optical system 7 is configured so that the laser light (end surface 8a of the optical fiber 8) forms an image on the observation target portion R each time the laser light irradiation range (magnification) on the observation target portion R is changed. The position of the focusing lens body (lens body 11a in the example of FIG. 2) is adjusted.

  The drive device 9 includes a guide mechanism 15, screw shafts 17a, 17b, and 17c, and actuators 19a, 19b, and 19c.

  The guide mechanism 15 includes holding and moving pieces 13a, 13b, and 13c that guide the holding and moving pieces 13a, 13b, and 13c in the optical axis direction when the holding and moving pieces 13a, 13b, and 13c are driven by the actuators 19a, 19b, and 19c. 13c is engaged. The guide mechanism 15 is fixed to the box 5. In the example of FIG. 2, the guide mechanism 15 is a guide bar extending in the optical axis direction.

  The screw shafts 17a, 17b, and 17c are provided for the holding and moving pieces 13a, 13b, and 13c, respectively, and extend in the optical axis direction. The screw shafts 17a, 17b, and 17c are screwed to the holding and moving pieces 13a, 13b, and 13c, respectively.

  Actuators 19a, 19b, and 19c are provided for the holding and moving pieces 13a, 13b, and 13c, respectively, and drive the holding and moving pieces 13a, 13b, and 13c in the optical axis direction of the varifocal optical system 7. The actuators 19a, 19b, and 19c are motors that move the holding and moving pieces 13a, 13b, and 13c in the optical axis direction by guiding the guide mechanism 15 by rotating the screw shafts 17a, 17b, and 17c. Each screw shaft 17a, 17b, 17c is coaxially coupled to the output shaft of the corresponding motor 13a, 13b, 13c.

  The driving force transmitting portions 13a1, 13b1, and 13c1 that receive driving force from the corresponding actuators 19a, 19b, and 19c in the holding and moving pieces 13a, 13b, and 13c are shifted from each other in the circumferential direction around the optical axis of the varifocal optical system 7. The actuators 19a, 19b, and 19c are arranged so as to partially overlap the corresponding driving force transmission portions 13a1, 13b1, and 13c1 when viewed from the optical axis direction.

  The laser projector 20 includes position sensors 21 a, 21 b, 21 c and a control device 22.

  The position sensors 21a, 21b, and 21c are provided for the holding and moving pieces 13a, 13b, and 13c, respectively, and detect the positions of the corresponding holding and moving pieces 13a, 13b, and 13c. In this example, each of the position sensors 21a, 21b, and 21c is a rotary encoder that detects the number of rotations of the corresponding screw shafts 17a, 17b, and 17c as the positions of the holding moving pieces 13a, 13b, and 13c in the optical axis direction.

Based on the positions of the holding moving pieces 13a, 13b, and 13c detected by the position sensors 21a, 21b, and 21c, the control device 22 sets the corresponding actuators 19a, 19b, and 19c for the holding moving pieces 13a, 13b, and 13c. By performing the control, the holding and moving pieces 13a, 13b, and 13c are moved to the set positions determined in advance, and the holding and moving pieces are positioned at the set positions.
The control device 22 has a storage unit 22a, and the setting positions are stored in the storage unit 22a.

  In the laser projector 20, after changing or adjusting the irradiation range of the laser light in the observation target portion R (for example, steps S <b> 4 and S <b> 5 described later), adjustment is performed to form an image (focus) of the laser light in the observation target portion R. This is performed (for example, step S6 described later). A specific example of the adjustment method of the laser projector 20 will be described with reference to the flowchart of FIG. 4 and the block diagram of FIG.

  In step S1, the distance (optical path length) from the varifocal optical system 7 to the observation target portion R on the furnace interior 3a side in the inserted state in which the box 5 is inserted from the hole 3c into the furnace interior 3a is obtained in advance. This distance is a distance from the reference position of the varifocal optical system 7 to the observation target portion R. This reference position is, for example, the most downstream position in the movable range of the most downstream holding moving piece 13c of the varifocal optical system 7.

  In step S2, a plurality of imaging sizes of laser light in the observation target portion R that is the target of step S1 are determined in advance for the distance obtained in step S1.

In step S3, while the laser beam is imaged on the observation target portion R in the insertion state in step S1, each of the holding moving pieces 13a, 13b, and 13c is set so that the image formation size becomes the value determined in step S2. The position is obtained in advance as a set position. These set positions are obtained for each imaging size determined in step S2.
In addition, control data in which the distance (optical path length), the imaging size, and the set positions of the lens bodies 11a, 11b, and 11c thus obtained are associated with each other is stored in the storage unit 22a.

  Regarding step S3, FIG. 5 shows the set positions of the holding moving pieces 13a, 13b, and 13c for each imaging size, which are obtained when the distance obtained in step S1 is 3 m. FIG. 5A shows the set positions of the holding moving pieces 13a, 13b, and 13c when the imaging size is a diameter of 302.9 mm. FIG. 5B shows the set positions of the holding and moving pieces 13a, 13b, and 13c when the imaging size is a diameter of 404.3 mm. FIG. 5C shows the set positions of the holding moving pieces 13a, 13b, and 13c when the imaging size is a diameter of 621.2 mm.

  In step S4, the box 5 is inserted from the hole 3c into the furnace interior 3a so that the box 5 is in the same state as the inserted state in step S1, and a person operates the input device 24 (see FIG. 6). Thus, one of the plurality of image formation sizes determined in step S3 is selected.

  In step S5, based on the selected imaging size and control data, the holding and moving pieces 13a, 13b, and 13c are set at the set positions of the holding and moving pieces 13a, 13b, and 13c associated with the imaging size, respectively. The actuators 19a, 19b, and 19c are controlled so that is positioned. This control is performed by the control device 22. In this example, the control device 22 controls the motors 19a, 19b, and 19c by controlling the motor drivers 18a, 18b, and 18c. The motor drivers 18a, 18b, and 18c are provided outside the box 5 and supply electric power to the motors 19a, 19b, and 19c, respectively.

In step S <b> 6, a process is performed in which the laser light (end surface 8 a of the optical fiber 8) that passes through the varifocal optical system 7 and is irradiated on the observation target portion R is imaged on the observation target portion R. That is, the image data of the observation target portion R obtained by the imaging device 39 of the imaging device 30 described later is displayed on the display 28 (see FIG. 6), and based on this display, the person instructs the command device 26 (see FIG. 6). ) Is adjusted, the image formation state in the observation target portion R is adjusted, and the laser beam is imaged on the observation target portion R. The lens body of the varifocal optical system 7 whose position is adjusted by this adjustment is a focusing lens body (the lens body 11a in the example of FIG. 2).
For example, when there is an error in the control data, the laser light can be accurately imaged on the observation target portion R by finely adjusting the position of the holding and moving piece 13a (lens body 11a). That is, the position of the holding and moving piece 13a can be adjusted (finely adjusted) so that the periphery of the laser light irradiation region in the observation target portion R is sharp.
Further, when the observation target part R has a depth and the distance from the light projection window 5a to the plurality of local positions in the observation target part R changes according to the local position, the position of the holding moving piece 13a is adjusted. As a result, the laser beam can be accurately imaged at a desired local position.
Further, when the box 5 is rotated around the axis of the box 5 in the inserted state and the laser light is irradiated to the different observation target portions R, the distance from the projection window 5a to the observation target portion R is observed. When changing according to the target part R, the laser beam can be accurately imaged on each observation target part R by adjusting the position of the holding and moving piece 13a.

  As for step S6, when the command device 26 is operated by a person, the actuator 19a is controlled via the motor driver 18a according to this operation, and the holding moving piece 13a is moved independently of the other holding moving pieces 13b and 13c. It can be made to. The command device 26 is provided outside the box 5. The command device 26 is configured to be able to control the actuators 19a, 19b, and 19c independently from each other and to control the plurality of holding and moving pieces 13a, 13b, and 13c independently from each other when operated by a person. It's okay.

In the following cases, steps S1 to S3 described above are performed a plurality of times.
When the distance calculated | required by said step S1 differs greatly with the direction of the box 5 when it inserts in the hole 3c, and the furnace interior 3a is observed in each direction.
When the distance calculated | required by said step S1 differs with the furnace 3 made into object, when inserting the box 5 in the hole 3c of the some furnace 3. FIG.
In such a case, the above steps S1 to S3 are performed for each different distance, and then, in step S4, one of the plurality of distances is selected by operating the input device 24, and Then, one of a plurality of image formation sizes determined in step S2 is selected for the selected distance. Thereafter, steps S5 and S6 are performed.

  The varifocal optical system 7 and the above-described control data can be created with high accuracy so that the laser beam forms an image on the observation target portion R in step S5. In this case, the varifocal optical system 7 functions as a zoom lens that eliminates the need for focus adjustment (ie, step S6). That is, in the present application, the varifocal optical system 7 is a concept that includes not only an optical system that is out of focus but also a zoom lens that is not out of focus when the focal length is changed.

  The laser projector 20 further includes a oscillating mirror 23 and a mirror driving device 25 as shown in FIG.

The oscillating mirror 23 is provided in the box 5 and reflects the laser light from the varifocal optical system 7 toward the projection window 5a.
The mirror driving device 25 adjusts the posture of the oscillating mirror 23 by oscillating the oscillating mirror 23 about the oscillation axis C1 by a desired angle. The mirror driving device 25 is controlled by a control device (not shown).
In the example of FIG. 3C, the mirror driving device 25 includes an actuator 27, a screw shaft 29, a moving piece 31, a guide mechanism 33, and a link mechanism 35.

The actuator 27 is a motor that is provided coaxially with the screw shaft 29 and rotates the screw shaft 29.
The screw shaft 29 extends in the optical axis direction and is screwed to the moving piece 31.
When the screw shaft 29 is rotated by the motor 27, the moving piece 31 is guided by the guide mechanism 33 and moved in the optical axis direction.
In this example, the guide mechanism 33 is a through hole formed in the fixing member 34 fixed to the box 5. The through hole 33 penetrates the fixing member 34 in the optical axis direction. When the moving piece 31 is fitted in the through-hole 33, the moving direction of the moving piece 31 is guided in the optical axis direction.
The link mechanism 35 converts the linear motion of the movable piece 31 into the swing motion of the swing mirror 23. In the example of FIG. 3C, the link mechanism 35 includes a first link 35a and a second link 35b. One end of the first link 35a is coupled to the moving piece 31 so as to be rotatable about the axis C2. The other end of the first link 35a is coupled to one end of the second link 35b so as to be rotatable about the axis C3. The other end of the second link 35b is rotatable around the swing axis C1. The swing mirror 23 is fixed to the second link 35b. The swing shaft C <b> 1 is fixed to the box 5.

  In the laser projector 20 described above, the following effects (1) to (4) are obtained.

(1) With the holding and moving pieces 13a, 13b, and 13c of the varifocal optical system 7, the imaging size of the laser beam can be adjusted while the laser beam is focused on the observation target portion R inside the furnace.

(2) The driving force transmission portions 13a1, 13b1, and 13c1 that receive the driving force from the corresponding actuators 19a, 19b, and 19c in the holding and moving pieces 13a, 13b, and 13c are circumferential directions around the optical axis of the varifocal optical system 7. The actuators 19a, 19b, and 19c are arranged so as to partially overlap the corresponding driving force transmission portions 13a1, 13b1, and 13c1 when viewed from the optical axis direction. The inner diameter of the box 5 can be kept small. Accordingly, the box 5 can be inserted into the furnace 3a through the narrow inspection hole 3c.
As an example, the motor 19c, 19b, 19d having a diameter of about 8 mm is used by using the varifocal optical system 7 in which the maximum diameter of the inner light beam is about 12 mm and the optical fiber end face 8a side focal length can be adjusted in the range of 6 mm to 15 mm. Can be used, the inner diameter of the box 5 can be about 50 mm.

(3) As described above, when the observation target portion R has a depth, a person operates the command device 26 to adjust the imaging position of the varifocal optical system 7 to a desired position in the depth direction. Can do. For example, when a connection hole for piping is formed on the furnace wall surface, a laser beam can be imaged at a desired position in the connection hole.
Conventionally, the laser beam could not be irradiated with a sufficient amount of light into such a pipe, but the laser beam could be irradiated with a sufficient amount of light into the pipe by adjusting the imaging size of the laser beam. . Furthermore, by adjusting the imaging range and imaging magnification with the imaging device 30 described later, it is possible to improve the image in the pipe, which has been unclear in the past.

(4) When the observation target portion R (for example, the furnace wall) emits radiation, the observation target portion R is adjusted to a light density that is easy to observe by adjusting the imaging size of the laser light in the observation target portion R. Can be irradiated with laser light. For example, even when the temperature in the furnace 3a becomes high and the laser beam becomes weaker than the radiation light in the furnace 3a, the varifocal optical system 7 reduces the laser irradiation range (laser beam imaging size). By irradiating the observation target part R with laser light with a sufficient light density, the high-temperature observation target part R can be observed.
In this case, since the image of the observation target portion R can be obtained at a desired magnification by a varifocal optical system 41 of the imaging device 30 described later, the furnace wall 3b can be observed in detail in a short time.

[Imaging device]
FIG. 7 shows an imaging device 30 according to an embodiment of the present invention provided in the internal observation device 10 of FIG. FIG. 7A is a partially enlarged view of the internal observation device 10 in FIG. FIG. 7B is a cross-sectional view taken along the line 7B-7B in FIG. FIG. 7A is a view taken in the direction of arrows 7A-7A in FIG. 7B, and is a view seen through the inside.
FIG. 8A is a view taken in the direction of arrow 8A-8A in FIG. 7B, and is a view seen through the inside. FIG. 8B is a view taken in the direction of arrows 8B-8B in FIG. 7B, and is a view seen through the inside.
FIG. 9A is a cross-sectional view taken along line 9A-9A in FIG. FIG. 9B is a view taken in the direction of arrows 9B-9B in FIG. 9A and is a view seen through the inside.
In FIG. 7A, lens bodies 45b and 45c described later and members related thereto are not shown. In FIG. 8A, the lens bodies 45a and 45c and members related thereto are not shown. In FIG. 8B, the lens bodies 45a and 45b and members related thereto are not shown. In FIG. 9B, the lens bodies 45a, 45b, and 45c and members related thereto are not shown.

  The imaging device 30 includes the above-described box body 5 that is inserted into the furnace interior 3a through a narrow hole 3c provided in the furnace wall 3b, and images the furnace interior 3a from the viewing window 5b provided in the box body 5. . The observation window 5b is made of, for example, a quartz plate.

  The imaging device 30 includes an imaging element 39, a varifocal optical system 41, and a driving device 43.

  The image sensor 39 generates image data based on the received light. The image sensor 39 converts the light received by the light receiving surface 39a into an electrical signal, and outputs the image data composed of the electrical signal. The image sensor 39 may use a CCD.

The varifocal optical system 41 is provided inside the box 5 and allows the observation target portion R to form an image on the light receiving surface 39a of the image sensor 39 through the light in the furnace 3a that has entered from the observation window 5b.
The varifocal optical system 41 has a function of adjusting the range of the observation target portion R imaged on the light receiving surface 39a (the angle of view of the imaging device 30). When the angle of view changes, the imaging surface of the observation target portion R by the varifocal optical system 41 deviates from the light receiving surface 39a. However, the varifocal optical system 41 receives the imaging surface in response to the change in the angle of view. In accordance with the surface 39a, the observation target portion R also has a function of forming an image on the light receiving surface 39a.

  The varifocal optical system 41 has a plurality of lens bodies 45a, 45b, 45c, and 45d arranged in series in the optical axis direction. Each lens body 45a, 45b, 45c, 45d includes one or a plurality of lenses 46 through which the laser light passes, and a holding moving piece that holds the one or more lenses 46 and is movable in the optical axis direction. 47a, 47b, 47c, 47d. At least two of the plurality of holding and moving pieces 47 a, 47 b, 47 c and 47 d can move independently of each other in the optical axis direction of the varifocal optical system 41. In the example of FIG. 7, the holding and moving pieces 47a, 47b, and 47c can move independently of each other. Note that the holding and moving piece 47d moves integrally with the holding and moving piece 47a by being connected to the holding and moving piece 47a by the connecting member 48. The holding and moving piece 47a and the holding and moving piece 47d extend from the inside of the lens barrel 55 to the outside of the lens barrel 55 through a long hole 49d described later and are coupled to the connecting member 48 in the radial direction of the lens barrel 55. The connecting member 48 extends in the axial direction (optical axis direction) of the lens barrel 55 outside the lens barrel 55.

  The driving device 43 is provided inside the box 5 and moves the plurality of holding and moving pieces 47a, 47b, and 47c in the optical axis direction independently of each other. Thereby, the light from each position in the observation target portion R can be imaged on the light receiving surface 39a while changing the angle of view. That is, the imaging magnification of the observation target portion R on the light receiving surface 39a by the varifocal optical system 41 can be adjusted.

  The drive device 43 includes guide mechanisms 49a, 49b, 49c, and 49d (see FIG. 10), screw shafts 51a, 51b, and 51c, and actuators 53a, 53b, and 53c.

The guide mechanisms 49a, 49b, 49c, and 49d engage with the holding and moving pieces 47a, 47b, 47c, and 47d so as to guide the holding and moving pieces 47a, 47b, 47c, and 47d in the optical axis direction. In the present embodiment, the guide mechanisms 49 a, 49 b, 49 c, 49 d are provided as long holes in the lens barrel 55. FIG. 10 is a perspective view of the lens barrel 55, showing the long holes 49a, 49b, 49c, and 49d.
The lens barrel 55 is provided in the box 5 and is fixed to the box 5. The lens barrel 55 accommodates a plurality of lens bodies 45a, 45b, 45c, 45d therein. A plurality of elongated holes 49 a, 49 b, 49 c, 49 d extending in the axial direction are formed on the side wall of the lens barrel 55. The long holes 49a, 49b, 49c, and 49d penetrate the side wall of the lens barrel 55 in the thickness direction of the lens barrel 55 and extend in the optical axis direction. The long holes 49a, 49b, 49c, and 49d are arranged so that the holding and moving pieces 47a, 47b, 47c, and 47d are moved in the optical axis direction when the holding and moving pieces 47a, 47b, 47c, and 47d are driven by the actuators 53a, 53b, and 53c, respectively. Is engaged with the holding and moving piece.
The holding and moving pieces 47a, 47b, and 47c are coupled to the lens bodies 45a, 45b, and 45c in the lens barrel 55, and pass through the long holes 49a, 49b, and 49c from the lens barrel 55 to the outside of the lens barrel 55. And screwed with the screw shafts 51a, 51b, 51c outside the lens barrel 55.

  The screw shafts 51a, 51b, 51c are provided for the holding and moving pieces 47a, 47b, 47c, respectively, and extend in the optical axis direction of the varifocal optical system 41. As described above, the screw shafts 51a, 51b, and 51c are screwed into the holding and moving pieces 47a, 47b, and 47c outside the lens barrel 55, respectively.

  The actuators 53a, 53b, and 53c are provided for the holding and moving pieces 47a, 47b, and 47c, respectively, and drive the holding and moving pieces in the optical axis direction of the varifocal optical system 41. The actuators 53a, 53b, and 53c are motors that move the holding and moving pieces 47a, 47b, and 47c in the optical axis direction by rotating the screw shafts 51a, 51b, and 51c and guiding the guide mechanisms 49a, 49b, and 49c. . Each screw shaft 51a, 51b, 51c is coaxially coupled to the output shaft of the corresponding motor 53a, 53b, 53c.

  According to the present embodiment, the driving force transmitting portions 47a1, 47b1, 47c1 that receive the driving force from the actuators 53a, 53b, 53c in the holding and moving pieces 47a, 47b, 47c are circumferential directions around the optical axis of the varifocal optical system 41. The actuators 53a, 53b, and 53c are arranged so as to partially overlap the corresponding driving force transmission portions 47a1, 47b1, and 47c1 when viewed from the optical axis direction.

  According to the present embodiment, the imaging device 30 includes position sensors 57a, 57b, 57c and a control device 59.

  The position sensors 57a, 57b, and 57c are provided for the plurality of holding and moving pieces 47a, 47b, and 47c, respectively, and detect the positions of the corresponding holding and moving pieces 47a, 47b, and 47c. In this example, the position sensors 57a, 57b, and 57c are rotary encoders that detect the rotational speeds of the corresponding screw shafts 51a, 51b, and 51c as the positions of the holding and moving pieces 47a, 47b, and 47c in the optical axis direction.

  The control device 59 controls the actuators 53a, 53b, and 53c based on the detected positions of the holding movement pieces for the holding movement pieces 47a, 47b, and 47c, thereby holding the holding movement pieces 47a up to a preset position. , 47b, 47c are moved to position the holding moving piece at the set position.

  The control device 59 has a storage unit 59a, and the setting positions are stored in the storage unit 59a.

  In the imaging device 30, after changing or adjusting the imaging magnification of the observation target portion R on the light receiving surface 39a of the image sensor 39 (for example, steps S14 and S15 described later), the observation target portion R is imaged on the light receiving surface 39a. (Focus) (for example, step S16 described later) is adjusted. A specific example of the adjustment method of the imaging apparatus 30 will be described based on the flowchart of FIG. 11 and the block diagram of FIG.

  In step S11, the distance (optical path length) from the varifocal optical system 41 to the observation target portion R in the furnace 3a in the inserted state in which the box 5 is inserted from the hole 3c into the furnace 3a is obtained in advance. This distance is a distance from the reference position of the varifocal optical system 41 to the observation target portion R. This reference position is, for example, the most upstream position in the movable range of the most upstream holding moving piece 45d of the varifocal optical system 41.

  In step S12, a plurality of imaging magnifications of the observation target portion R on the light receiving surface 39a of the image sensor 39 are determined in advance for the distance obtained in step S11.

In step S13, the holding moving pieces 47a, 47b, and 47c are formed so that the imaging target portion R is imaged on the light receiving surface 39a in the insertion state in step S11, and the imaging magnification becomes the value determined in step S12. Is determined in advance as a set position. These set positions are obtained for each imaging magnification determined in step S12.
In addition, control data in which the distance (optical path length), the imaging magnification, and the setting positions of the lens bodies 45a, 45b, and 45c thus obtained are associated with each other is stored in the storage unit 59a.

  Regarding step S13, FIG. 12 shows the set positions of the holding moving pieces 47a, 47b, and 47c for each imaging magnification (light receiving surface side focal length) obtained for the case where the distance obtained in step S11 is 3 m. FIG. 12A shows the set positions of the holding moving pieces 47a, 47b, and 47c when the light receiving surface side focal length is 34.6 mm. FIG. 12B shows the set positions of the holding moving pieces 47a, 47b, and 47c when the light receiving surface side focal length is 80.0 mm times. FIG. 12C shows the set positions of the holding moving pieces 47a, 47b, 47c when the light receiving surface side focal length is 180.0 mm.

In step S14, the box 5 is inserted from the hole 3c into the furnace interior 3a so that the box 5 is in the same state as the inserted state in step S11, and the input device 24 (see FIG. 6) is operated by a person. Thus, one of a plurality of imaging magnifications determined in step S3 is selected.
In addition, insertion of the box 5 in step S14 and step S4 is one operation. That is, by setting the box 5 to the inserted state in step S14, the box 5 is set to the inserted state in step S4.

  In step S15, on the basis of the selected imaging magnification and the control data, the holding and moving pieces 47a, 47b, 47b, 47b, 47c are respectively set at the set positions of the holding and moving pieces 47a, 47b and 47c associated with the imaging magnification. The actuators 53a, 53b, and 53c are controlled so that 47c is positioned. This control is performed by the control device 59. The control device 59 controls the motors 53a, 53b, and 53c by controlling the motor drivers 58a, 58b, and 58c. The motor drivers 58a, 58b, and 58c are provided outside the box 5 and supply power to the motors 53a, 53b, and 53c.

In step S16, a process for forming an image of the observation target portion R on the light receiving surface 39a is performed. That is, the image data of the observation target portion R obtained by the imaging element 39 of the imaging device 30 is displayed on the display 28 (see FIG. 6), and based on this display, a person selects the command device 26 (see FIG. 6). By operating, the imaging state on the light receiving surface 39a of the image sensor 39 is adjusted, and the observation target portion R is imaged on the light receiving surface 39a. The lens body of the varifocal optical system 41 whose position is adjusted by this adjustment is a focusing lens body (lens bodies 45a and 45d in the example of FIG. 7).
For example, when there is an error in the control data, the position of the holding and moving pieces 47a and 47d (lens bodies 45a and 45d) is finely adjusted so that the observation target portion R is accurately imaged on the light receiving surface 39a. be able to.
Further, when the observation target portion R has a depth and the distances from the observation window 5b to a plurality of local positions in the observation target portion R change according to the local positions, the positions of the holding moving pieces 47a and 47d are adjusted. Thus, a desired local position can be accurately imaged on the light receiving surface 39a.
Further, when the box 5 is rotated about the axis of the box 5 in the inserted state and a different observation target part R is imaged, the distance from the observation window 5b to the observation target part R is set to the observation target part R. When changing accordingly, the positions of the holding and moving pieces 47a and 47d can be adjusted so that each observation target portion R can be accurately imaged on the light receiving surface 39a.

  With respect to step S16, when the command device 26 is operated by a person, the actuator 53a is controlled via the motor driver 58a according to this operation, and the holding moving pieces 47a and 47d are moved relative to the other holding moving pieces 47b and 47c. It can be moved independently. The command device 26 is configured to be able to control the actuators 53a, 53b, 53c independently of each other and to control the plurality of holding moving pieces 47a, 47b, 47c independently of each other when operated by a person. It's okay.

In the following cases, the above steps S11 to S13 are performed a plurality of times.
When the distance calculated | required by said step S11 differs greatly with the direction of the box 5 when it inserts in the hole 3c, and the furnace interior 3a is observed in each direction.
When the distance calculated | required by said step S11 differs with the furnace 3 made into object, when inserting the box 5 in the hole 3c of the some furnace 3. FIG.
In such a case, the above steps S11 to S13 are performed for each different distance, and then, in step S14, one of the plurality of distances is selected by operating the input device 24, and Then, one of a plurality of imaging magnifications determined in step S12 is selected for the selected distance. Thereafter, steps S15 and S16 are performed.

  The varifocal optical system 41 and the above-described control data can be created with high accuracy so that the laser beam forms an image on the observation target portion R in step S15. In this case, the varifocal optical system 41 functions as a zoom lens that eliminates the need for focus adjustment (ie, step S16). That is, in this application, the varifocal optical system 41 is a concept including not only an optical system that is out of focus but also a zoom lens that is not out of focus when the focal length is changed.

  The imaging device 30 further includes a oscillating mirror 61 and a mirror driving device 63 as shown in FIG. 9B, for example.

The oscillating mirror 61 is provided in the box 5 and reflects light incident from the inside 3 a of the furnace through the observation window 5 b toward the varifocal optical system 41.
The mirror driving device 63 adjusts the posture of the oscillating mirror 61 by oscillating the oscillating mirror 61 about the oscillation axis C4 by a desired angle. The mirror driving device 63 is controlled by a control device (not shown).
In the example of FIG. 9B, the mirror drive device 63 includes an actuator 65, a screw shaft 67, a moving piece 69, a guide mechanism 71, and a link mechanism 73.

The actuator 65 is a motor that is provided coaxially with the screw shaft 67 and rotates the screw shaft 67.
The screw shaft 67 extends in the optical axis direction and is screwed to the moving piece 69.
When the screw shaft 67 is rotated by the motor 65, the moving piece 69 is guided by the guide mechanism 71 and moved in the optical axis direction.
In this example, the guide mechanism 71 is a through hole formed in a fixing member 75 fixed to the box 5. The through hole 71 passes through the fixing member 75 in the optical axis direction. Since the moving piece 69 is fitted in the through hole 71, the moving direction of the moving piece 69 is guided in the optical axis direction.
The link mechanism 73 converts the linear motion of the moving piece 69 into the swing motion of the swing mirror 61. In the example of FIG. 9C, the link mechanism 73 includes a first link 73a and a second link 73b. One end of the first link 73a is coupled to the moving piece 69 so as to be rotatable about the axis C5. The other end of the first link 73a is coupled to one end of the second link 73b so as to be rotatable about the axis C6. The other end of the second link 73b is rotatable around the swing axis C4. A swing mirror 61 is fixed to the second link 73b. The swing shaft C4 is fixed to the box 5.

The imaging device 30 includes an optical filter 77 and a cold filter 79 as shown in FIG.
The optical filter 77 is provided in the box 5 and is located upstream of the image sensor 39. In the example of FIG. 7A, the optical filter 77 is located between the imaging element 39 and the lens body 45 a and at the end of the lens barrel 55. In one example, the optical filter 77 transmits only light having the same wavelength as the laser light from the laser projector 20. Instead, the optical filter 77 may transmit not only light having the wavelength of the laser light but also light having other desired wavelengths.
The cold filter 79 is provided in the box 5 and cuts heat rays from the furnace 3a. In the example of FIG. 7A, it is located upstream of the lens body 45d and at the end of the lens barrel 55.

  In the imaging device 30 according to the embodiment of the present invention described above, the following effects (5) to (7) are obtained.

(5) By adjusting the position of each holding and moving piece 47a, 47b, 47c of the varifocal optical system 41, the imaging magnification can be adjusted while the observation target portion R is imaged on the light receiving surface 39a of the image sensor 39. Therefore, by obtaining an enlarged image of the observation target portion R, it is possible to observe damage in the furnace wall in more detail as compared with the conventional case.

(6) The driving force transmitting portions 47a1, 47b1, and 47c1 that receive the driving force from the actuators 53a, 53b, and 53c in the holding and moving pieces 47a, 47b, and 47c are shifted from each other in the circumferential direction around the optical axis of the varifocal optical system 41. The actuators 53a, 53b, 53c are arranged so as to partially overlap the corresponding driving force transmission portions 47a1, 47b1, 47c1 when viewed from the optical axis direction. The inner diameter can be kept small. Accordingly, the box 5 can be inserted into the furnace 3a through the narrow inspection hole 3c.
As an example, the maximum diameter of the internal luminous flux is about 12 mm, and an image can be formed on the image sensor 39 having a light receiving surface 39a of about 0.5 inches, and the focal length on the light receiving surface side can be adjusted in the range of 36 mm to 180 mm. When the varifocal optical system 41 is used and motors 53a, 53b, and 53c having a diameter of about 8 mm are used, the inner diameter of the box 5 can be set to about 50 mm.

(7) As described above, when the observation target portion R has a depth, the observation target portion R can be adjusted by adjusting the positions of the holding and moving pieces 47a, 47b, 47c by manipulating the command device 26. A desired position in the depth direction can be imaged on the light receiving surface 39 a of the image sensor 39. For example, when a connection hole for piping is formed on the furnace wall surface, a desired position in the connection hole can be imaged on the light receiving surface 39 a of the image sensor 39.

[Example]
The result of observing the observation target portion R inside the internal space 3a of the hot stove 3 using the internal observation device 10 including the laser projection device 20 and the imaging device 30 described above will be described.

(Conditions of equipment used)
Laser used: Second harmonic of YAG laser (wavelength 532 nm)
Laser intensity at the observation target portion R: 0.7 W / cm ²
Image sensor 39: CCD
Inner diameter of box 5: 50 mm
Optical filter 77: a transmission filter that mainly transmits light having a wavelength of 532 nm

(Location of observation target)
As the observation target portion R, the furnace wall 3b located 3 m from the box 5 and the inner surface of the connecting pipe located 13 m from the box 5 were selected. The connecting pipe is a pipe connected to a connection hole formed in the furnace wall 3b.

  FIG. 13 shows an image (in the case of the present invention in this figure) obtained by imaging the position of the above-described observation target portion with the internal observation apparatus 10 according to the embodiment of the present invention under the conditions of the above-described device used, and an image obtained by a comparative example. Indicates.

In the comparative example, the image of FIG. 13 was obtained under the following conditions.
In the comparative example, the optical system that projects laser light and the optical system of the imaging apparatus have a fixed focus at a position 3 m from the box 5. In the comparative example, the laser intensity in the observation target portion R is the same as described above when the observation target portion R is the furnace wall 3b located at a position 3 m from the box body 5, but the observation target portion R is in the box shape. In the case of the inner surface of the connecting pipe at a position of 5 to 13 m, it is lowered due to the fixed focus. In the comparative example, the other points are the same as in the case of the present invention described above.

  As can be seen from FIG. 13, when the distance to the observation target portion R is 3 m, a clear image can be obtained in both the present invention and the comparative example. On the other hand, when the distance to the observation target portion R is 13 m, a clear image is obtained in the present invention, but the image obtained in the comparative example is not focused and is unclear.

  The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention. For example, you may change as follows. The points not described below may be the same as described above, or may be changed as appropriate.

In the above description, the internal space forming body 3 is a furnace, and the internal observation device 10 is an in-furnace observation device. However, the internal space forming body 3 may be another (for example, a container).
The internal observation device 10 provided with the imaging device 30 of the present invention can be used for both the cold observation and the hot observation in the internal space forming body 3, but the inside is 1100 ° C. or higher and the radiation is increased. It is particularly suitable for hot observation in a furnace such as a hot stove or heating furnace that emits light. That is, when the laser projection device 20 irradiates the observation target portion in the furnace having an interior of 1100 ° C. or higher with the laser projection device 20, the intensity (unit) of the laser beam emitted by the laser projection device 20 in the laser irradiation region The energy of the laser light per area) can be made higher than the intensity of the radiant light (radiation light emission energy per unit area), thereby obtaining a clearer image of the observation target portion with the imaging device 30. can do.

  Instead of the oscillating mirrors 23 and 61, a mirror driven by another method may be used. Further, the number of mirrors may be arbitrary.

  The oscillating mirrors 23 and 61 may be omitted. In this case, the projection window 5a or the observation window 5b is located on an extension line of the optical axis of the varifocal optical system.

  In FIG. 1, the laser projector 20 and the imaging device 30 are arranged in series. However, the laser projector 20 and the imaging device 30 may be arranged in parallel. For example, when the length in which the box 5 can be inserted into the furnace 3a is limited, the laser projector 20 and the imaging device 30 may be arranged in parallel.

  The laser projection device 20 may be any device that irradiates the observation target portion R with laser light from the inside of the box 5 and may not have the varifocal optical system described above.

  In the varifocal system 7 of the laser projector 20, the number of lens bodies that can move independently from each other is such that the observation target R forms an image of the laser beam upstream of the varifocal optical system 7, and the object to be observed. Any number that can adjust the irradiation range (imaging size) of the laser beam in the portion R may be used.

  The number of lens bodies that can move independently of each other in the varifocal optical system 41 of the image pickup device 30 changes the angle of view and forms light from each position in the observation target portion R on the light receiving surface 39a. Any number can be used.

  Only one of the control device 22 and the command device 26 may be provided. Further, only one of the control device 59 and the command device 26 may be provided.

  In the above-described embodiment, the number of lens bodies that can move independently from each other in the optical axis direction of the varifocal optical system 7 in the laser projector 20 is three, but the present invention is not limited to this. . That is, according to the present invention, in the varifocal optical system 7, the number of lens bodies that can be moved independently of each other in the optical axis direction may be two or more. It depends on the number.

  In the above-described embodiment, the number of lens bodies that can move independently of each other in the optical axis direction of the varifocal optical system 41 in the imaging device 30 is the same as the lens body 45a at the rear end in the optical axis direction and the optical axis. Except for the lens body 45d at the tip in the direction, the number is two, but the present invention is not limited to this. That is, according to the present invention, when the lens body 45a at the rear end in the optical axis direction and the lens body 45d at the front end in the optical axis direction are provided to move together, the varifocal optical system 41 other than these lens bodies 45a and 45d. In addition, the number of lens bodies that can move independently of each other in the optical axis direction only needs to be two or more, and differs depending on the type and number of lenses 46 incorporated in each lens body.

  In the above-described embodiment, in the imaging device 30, the function (focusing function) of the observation target portion R being focused on the light receiving surface 39a by the lens body 45a at the rear end in the optical axis direction and the lens body 45d at the front end in the optical axis direction that move together. The other lens bodies 45b and 45c have the function of changing the angle of view of the imaging device 30 (zoom function), but the present invention is not limited to this. That is, the lens bodies 45a and 45d having a focus function may be made stationary lens bodies without moving, and the image sensor 39 may be movable in the optical axis direction of the varifocal optical system 41. In this case, in the varifocal optical system 41, the number of lens bodies that can move independently of each other in the optical axis direction may be two or more. In this case, in moving the image sensor 39, the screw shaft 51 a is coupled to the image sensor 39 and holds the image sensor 39 (not shown) instead of being screwed to the above-described holding and moving piece 47 a. The motor 53a, the screw shaft 51a, and the position sensor 57a are provided at positions in the optical axis direction that match the image sensor 39. Further, in this case, when the entire moving range of the image sensor 39 is within the lens barrel 55 with respect to the axial direction of the lens barrel 55, the guide mechanism 49 a may be a long hole of the lens barrel 55. When the entire movement range is outside the lens barrel 55 with respect to the axial direction of the lens barrel 55, the guide mechanism 49a is configured by other means such as a guide bar extending in the optical axis direction of the varifocal optical system 41. Other points are the same as described above. For example, in step S15, the control device 59 controls the motors 53a, 53b, and 53c based on the control data as described above.

  In the above-described embodiment, in the imaging device 30, the lens bodies 45a and 45d are moved together. However, the lens bodies 45a and 45d that move together may be omitted. In this case, in the varifocal optical system 41 of the imaging device 30, the number of lens bodies that can be moved independently of each other in the direction of the optical axis may be two or more. It depends on the number.

3 Furnace (internal space forming body), 3a In the furnace, 3b Furnace wall, 3c Hole in the furnace wall, 5 Box, 5a Projection window, 5b Viewing window, 7 Varifocal optical system, 8 Optical fiber, 8a End face of optical fiber , 9 Driving device, 10 Internal observation device, 11a, 11b, 11c Lens body, 12 Lens, 13a, 13b, 13c Holding and moving piece, 15 Guide mechanism, 17a, 17b, 17c Screw shaft, 18a, 18b, 18c Motor driver, 19a, 19b, 19c Actuator, 20 Laser projector, 21a, 21b, 21c Position sensor, 22 Control device, 22a Storage unit, 23 Swing mirror, 24 Input device, 25 Mirror drive device, 26 Command device, 27 Actuator, 29 screw shaft, 30 imaging device, 31 moving piece, 33 guide mechanism, 34 fixing member, 35 link mechanism, 35a first link, 5b Second link, 39 Image sensor, 41 Varifocal optical system, 43 Drive device, 45a, 45b, 45c, 45d Lens body, 46 Lens, 47a, 47b, 47c Holding moving piece, 48 Connecting member, 49a, 49b, 49c Guide mechanism (long hole), 51a, 51b, 51c Screw shaft, 53a, 53b, 53c Actuator, 55 Lens barrel, 57a, 57b, 57c Position sensor, 58a, 58b, 58c Motor driver, 59 Control device, 59a Storage unit, 61 oscillating mirror, 63 mirror driving device, 65 actuator, 67 screw shaft, 69 moving piece, 71 guide mechanism, 73 link mechanism, 75 fixing member, 77 optical filter, 79 cold filter, R observation target part

Claims (7)

A box that is inserted into the internal space forming body through a hole provided in the wall of the internal space forming body having the internal space is provided, and an observation target portion inside the internal space forming body is imaged from a viewing window provided in the box An imaging device that
An image sensor provided inside the box and generating image data based on light received from the observation target part;
A varifocal optical system that is provided inside the box and forms an observation target portion on the light receiving surface of the imaging device;
The varifocal optical system has a plurality of lens bodies arranged in series, and each lens body includes one or a plurality of lenses through which light from an observation target portion passes, and the one or a plurality of lenses. Holding and moving piece that is movable and movable in the optical axis direction of the varifocal optical system,
At least two of the holding and moving pieces are holding and moving pieces that can move independently of each other in the optical axis direction of the varifocal optical system,
The imaging magnification of the observation target portion on the light receiving surface by the varifocal optical system is adjusted by moving the at least two holding and moving pieces in the optical axis direction independently of each other provided in the box. A drive device for
The drive device
An actuator that is provided for each of the at least two holding and moving pieces, and that drives the corresponding holding and moving pieces in the optical axis direction of the varifocal optical system;
The driving force transmitting portions that receive driving force from the corresponding actuators in the at least two holding moving pieces are arranged so as to be shifted from each other in the circumferential direction around the optical axis of the varifocal optical system. An imaging apparatus, wherein the imaging apparatus is disposed so as to overlap with the corresponding driving force transmission portion when viewed from the axial direction. A position sensor provided for each of the at least two holding and moving pieces, and detecting a position of the corresponding holding and moving piece;
For each of the at least two holding and moving pieces, a control device that moves the holding and moving piece to a predetermined set position by controlling an actuator based on the detected position of the holding and moving piece, and
In a state where the box is inserted from the hole into the internal space formation body, a plurality of the imaging magnifications are predetermined with respect to a known distance from the varifocal optical system to the observation target portion inside the internal space formation body. And
The position of each holding moving piece for obtaining the imaging magnification for each imaging magnification is obtained in advance as the set position and stored in a storage unit of the control device. The imaging apparatus according to 1. The driving device includes:
A guide mechanism for engaging the holding and moving piece so as to guide the at least two holding and moving pieces in the optical axis direction;
A screw shaft provided for each of the at least two holding and moving pieces, extending in the optical axis direction, and screwed into the corresponding holding and moving piece;
3. The motor according to claim 1, wherein each of the actuators is a motor that moves the corresponding holding moving piece in the optical axis direction by guiding the guide mechanism by rotating the corresponding screw shaft. The imaging device described in 1. Provided in the box, provided with a lens barrel that accommodates each lens inside,
A plurality of elongated holes extending in the axial direction are formed on the side wall of the barrel,
The imaging device according to claim 3, wherein each of the plurality of elongated holes is formed as the guide mechanism that engages with the at least two holding and moving pieces.   Each of the at least two holding and moving pieces is coupled to the lens body in the lens barrel, extends from the lens barrel through the elongated hole to the outside of the lens barrel, and the screw outside the lens barrel. The imaging apparatus according to claim 4, wherein the imaging apparatus is screwed with a shaft. A display for displaying the image data;
The imaging apparatus according to claim 1, further comprising: a command device capable of controlling the actuators independently of each other by being operated by a person. An internal observation method using the imaging device according to any one of claims 1 to 6,
(A) inserting the box into the internal space forming body,
(B) The observation target part is imaged by an imaging device and displayed on a display;
(C) An internal observation method, wherein the position of the lens body is adjusted so that the displayed observation target portion is imaged on a light receiving surface of the imaging device.