GB2231231A

GB2231231A - Miniature TV camera inspection system

Info

Publication number: GB2231231A
Application number: GB9000376A
Authority: GB
Inventors: Pearpoint Limited
Original assignee: Pearpoint Ltd
Current assignee: Pearpoint Ltd
Priority date: 1989-01-06
Filing date: 1990-01-08
Publication date: 1990-11-07
Also published as: GB9000375D0; GB9000376D0; GB2228644A; GB8900263D0

Abstract

A miniature TV camera system comprises a miniature TV camera at the remote end of a length of flexible connector, and a camera control unit which receives and transmits signals from and to the camera via a connector. The camera has a nose portion 47 which is tapered to facilitate entry through restricted openings and to facilitate close inspection of difficult areas, e.g. the side of a conduit, and the remote ends of two bundles 23A of optical fibres which extend through the connector form a ring around the camera lens 16, means being provided to selectively illuminate the bundles for illumination from selected arcs of the ring. The flexible connection accommodates services for the camera, including the optical fibres and also air or liquid lines for control purposes. <IMAGE>

Description

MINIATURE TV CAMERA SYSTEMS This invention relates to miniature TV camera systems, particularly for use in the inspection of inaccessible areas such as the interiors of conduits, for example sewers and other pipelines, and of vessels and industrial machines.

Camera systems of this kind usually comprise a miniature TV camera at the remote end of a length of flexible connector, a camera control unit which has a VDU screen and receives signals from the camera via the connector, and a remote control unit at or connected to the camera control unit.

Various forms of TV camera inspection systems are known, such as the PEARPOINT FLEXIPROBE system where the flexible connector comprises a flexible but resilient rod which pushes a possibly larger TV camera through a conduit or the like. Alternative systems have connectors which are simply flexible, and require the camera unit to be pulled or otherwise driven through the inaccessible areas.

It is an object of the present invention to provide improvements in or variations of such known systems.

According to a first aspect of the present invention, the camera comprises a body part having an end which is of tapered form to facilitate entry through restricted openings in conduits or other inaccessible areas, and possibly also to facilitate close inspection of the inner face of the conduit.

According to a further aspect of the present invention, the camera connector accommodates services which include at least two bundles of optical fibres the remote ends of which form a ring around the camera lens, and means are provided for selectively illuminating the bundles to provide for illumination from one or more selected arcs of the ring.

According to yet a further aspect of the present invention, the camera connector accommodates services which terminate in a plug or socket at the leading end of the connector to be coupled to a socket or plug in the trailing end of the camera.

The aforementioned connector may comprise a hose-like member which accommodates services for operating the camera, said services including fluid power lines, with the end region of the member where the camera is mounted being provided with at least two opposed parts which are selectively expansible under fluid pressure to provide an articulating effect. Preferably, two adjacent units are arranged to articulate independently of one another so that the hose-like member can be bent to a U-shaped or to an S-shaped form.

The connector may also comprise a hose-like member which accommodates fluid power lines which inflate and/or deflate a bellows at the camera to drive the camera focusing mechanism. An iris amy be operated in a similar manner.

The connector may also comprise a hose-like member accomodating fluid power lines, with at least one nozzle being provided in the region of the camera to discharge fluid to cool operating parts of the camera or the lights of the camera. Suitably, the fluid, which will usually be air, is bled from the aforementioned bellows.

The connector may also be provided with an inflatable sheath to expand around and so centre and/or hold the connector in a conduit. Suitably, the sheath is located adjacent to the camera to centre and hold the camera.

The connector may also accomodate fluid power lines, with rearwardly directed nozzles being provided at or near the camera to provide fluid jets to drive the camera forwardly through the conduit.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which; Figure 1 is a diagrammatic view showing the layout of the components of a miniature TV camera system according to the invention, and comprising a TV camera, a camera control unit connected to the camera by a hose-like connector, and a remote control unit for the camera; Figure 2A is a side view of the miniature TV camera mounted at the end of two articulating units of the hoselike connector:: Figures 2B and 2C are end view B and a section on the line C-C of Fig. 2A, both enlarged; Figure 3 is a view illustrating the articulations of the hose-like connector; Figures 4A, 4B and 4C are detail sections through alternative constructions of articulating units of the hose-like connector; Figures 4D, 4E and 4F are further views showing details of alternative forms of articulating units; Figure 5A is a longitudinal section through the miniature TV camera; Figures SB and 5C are sections on the lines B-B and C-C of Fig. 5A, both on an enlarged scale; and Figures 6A and 6B are views showing an inflatable sheath for centering and/or holding the hose-like connector.

Referring to Fig. 1 of the drawings, the system comprises a minature TV camera 10, a camera control unit 11 and a remote control unit 12 for the TV camera.

The camera 10 is connected to the camera control unit by means of a plug-in hose-like connector 13 of variable length.

At the remote end of the connector, two units 13A and 13B provide for controlled articulation. The camera control unit 11 houses the camera light source, video signal processing electronics, and pneumatic control valve gear with its electronics and also provides a TV monitor or VDU 14.

The remote control unit 12 may have a joy-stick 15 and other means for controlling the camera and its operation.

Alternatively, the remote control unit which is not in itself part of the present invention could be incorporated in the camera control unit. Likewise, the camera control unit 11 may be of a more or less conventional type similar to that incorporated in the aforementioned PEARPOINT FLEXIPROBE system.

Figs. 2A and 2B show the TV camera with its compound 4element lens assembly 16, but a 7-element assembly has produced improved optical resolution and has reduced chromatic aberration. The camera also has a lighting ring 17, and is mounted at the remote end of the first articulat- ing unit 13A of the hose-like connector. Section 2C indicates the various services, including air and other lines, which are incorporated in the hose-like connector to provide for articulation of the units 13A and 13B to the configurations shown in Fig. 3, and provide other control services for the camera.More specifically, the connector 13 comprises an outer hose 18 which accommodates three air lines 19 leading to three bellows 20 in articulation unit 13A, three bellows 21 for operating the unit 13B, a central core or strain relief cable 22 which will subsequently be described briefly, two lighting guides 23, three camera wiring conduits 24 and an air line 25 for focus-control and cooling. The remaining spaces 26 between the various lines provide passages for air pressure which leads to rearwardly-directed nozzles 27 in a jetting section 28 of the connector which is located between units 13A and 13B. The function of these jetting nozzles is to drive the camera forwardly through the conduit which is to be inspected, and it will be appreciated that the camera is retracted simply by pulling on the flexible but sturdy hose-like connector 13 and the internal strain-relief cable 22.

Fig. 3 illustrates possible configurations produced by articulations of the two independently-controlled units 13A and 13B, and Figs. 4A, 4E and 4C show various forms of bellows or diaphragm systems which produce these articulations.

In the construction illustrated in Fig. 4A, each articulating unit comprises a series of shaped discs 29 which are mounted on the central strain-relief cable 22 and through which pass two tubular concertina-like bellows 20A of suitably elastic material. The cable 22 is springloaded to urge the discs together, but selective controlled inflation of one or more of these bellows will cause the discs to tilt and thus bend the unit in a desired direction and by a desired amount, as shown in Fig. 3. It will be noted that the pitch of the waisted portions 30 of each bellows registers with the spacing between the apertured webs 31 of the discs.If we consider unit 13A, air is fed to its bellows (20) through one or two of the lines 19 shown in Fig. 2C; if we consider unit 13B, it will be appreciated that the bellows (21) are selectively activated by three air lines (not shown) similar to air lines 19.

In the construction illustrated in Fig. 4B, the unit comprises a series of pairs of opposed discs 32 which are again urged together by the spring-loaded cable 22. In this case, bellows 20B extend through openings in the discs and accommodate tubular inserts 33. When one of the bellows is inflated, reflex sections 34 will straighten to a degree, and so tilt the discs by separation at one side to effect bending of the unit 13A or 13B.

Fig. 4C shows an envisaged alternative construction where flattened bellows or tubes 35 extend through undulating passageways between inserts 36 and discs 37. Pressurising of a tube 35 will cause the tube to expand and straighten and so tilt the discs 37 to bend the articulating unit.

Figs. 4D show adjacent discs 38 forming an articulating unit and having staggered openings 39 to receive undulating or zig-zag tubes such as 35. It will also be noted that openings 40, for passage of services such as camera wiring, are slightly staggered in the axial direction to minimise the danger of a taut line rupturing during bending of an articulating unit.

Figs. 4E show a further alternative form of bellows 41 which is of tubular shape with the wall of the tube formed with a series of shaped 'bores 42. Selective pressurisation of these bores will again produce bending of the articulating unit.

Fig. 4F shows further alternative forms of discs for the articulating units, which might be employed in conjunction with the bellows 41. Discs 44 are pivoted together, with adjacent pivots being angularly staggered by 90". Apertured discs 45 nest together, and are universally pivotal. Discs 46 lock together around their edges, but can tilt by telescoping.

The TV camera construction is shown in some detail in Figs. SA, SB and 5C. The camera body has a nose portion 47 which is of tapered form to facilitate entry through restricted openings and to improve the inspection of recessed and similarly difficult areas such as the burner can t8 of a jet engine which is shown in Fig. 3.

The nose portion houses the lens assembly 16 and a colour correction filter 50 for ' CCD 51 which is located in the cylindr cal part 52 of the camera body just ahead of its electronics unit 53. The CCD assembly, including the filter, the CCD and the electronics unit is urged rearwardly by a focus return spring 54, against the action of a bellows 55 according to the invention. The CCD assembly is slideable within a chassis 56 and can be moved by the bellows 55 to effect focusing; this allows a relatively large aperture lens 16 to be employed.

The bellows can be inflated as required, by air which is fed through line 25 (Fig.2C). Also according to the invention, a bleed orifice (not shown) may be provided in the. front wall of the bellows 55 to direc= an air jet over the CCD assembly, and so effect cooling. Such cooling is particularly useful when the camera is to focus on a dark distant object; then, the camera is at infinity focus and a picture intensifier may be introduced. The resulting heat produced can be effectively handled by the air-cooling according to the invention and, at infinity focus, the air pressure within the bellows is at maximum. The cooling air is suitably exhausted through a unit in the camera casing. In an alternative arrangement, cooling air can be fed through a separate pipe.

At the rear of the camera casing is an array of wiring pins 57 at the ends of flexi-rigid wiring ribbons 58 to provide a plug for connection with a mating socket 59 at the forward end of articulating unit 13A. Connections for one or more air lines, and also optical couplings, are included in the plug and socket connections, and this arrangement allows the camera unit to be readily replaced for servicing or exchanged for an alternative type of camera or other video probe. Suitable latches or other locking means are provided to prevent accidental removal.

The fibre-optic light guides 23 indicated in Fig. 2C extend to the socket 59 and then continue as upper and lower fibre bundles 23A and 23B in the camera, being connected to the guides by abutment under tension and where optical grease is provided.

The bundles 23A and 23B terminate in the lighting ring 17 (Fig. 2B) which comprises upper and lower semi-circles.

The bundles can be selectively illuminated to vary the camera lighting, which can be very useful in the inspection of confined spaces or difficult areas such as 48 in Fig. 3. More than two bundles may be provided to converge at the lighting ring.

Figs. 6A and 6B illustrate an arrangement for holding the connector 13 central and steady within a conduit.

A sheath 60 formed of flexible resilient material, around the connector, is clamped at its forward end 61 and secured to a slidable sleeve 62 at its rearward end.

On inflating the sheath so that it expands from the retracted position of Fig. 6A, the flexible or rubber-like body balloons outwardly to engage the wall of the surrounding conduit being inspected. The connector is thus secured in a central position and the camera 10 can be swung around by the articulating units 13A and 13B. To deflate the sheath, suction is applied and the sheath body is then drawn taut against the body of the connector, as the sleeve 62 retracts under appropriate traction or possibly by the action of the sheath.

Suitably, the air supply passes through gaps or passageways between the connector and the sleeve.

Reference has so far been made simply to air, which is usually the most convenient gas to use. However, inert gasses may be more appropriate to hazardous situations, and a suitable liquid may alternatively be employed.

The temperature of the fluid may be adjusted as required.

Claims

1. A miniature TV camera system comprising a miniature TV camera mounted at the remote end of a length of flexible connector through which signals are transmitted to and from a camera control unit, characterised in that said camera comprises a body part having an end which is of tapered form to facilitate entry through restricted openings in conduits or other inaccessible areas.

2. A miniature TV camera system as claimed in Claim 1, in which the tapered end also facilitates close inspection of the inner face of the conduit.

3. A miniature TV camera system comprising a miniature TV camera mounted at the remote end of a length of flexible connector through which signals are transmitted to and from a camera control unit, characterised in that at the remote ends of at least two bundles of optical fibres form a ring around the camera lens, and means are provided for selectively illuminating the bundles to provide for illumination from one or more selected arcs of the ring.

4, A miniature TV camera system according to any preceding Claim, in which a socket or plug in the trailing end of the camera is provided to be coupled to a plug or socket at the leading end of the connector which accommodates services for the camera.

5. A miniature TV camera system as claimed in any preceding Claim, in which said connector accommodates fluid power lines which inflate and/or deflate a bellows at or in the camera to drive the camera focusing mechanism and/or an iris opening/closing mechanism.

6. A miniature TV camera system as claimed in any preceding Claim, in which said connector accommodates fluid power lines, and at least one nozzle is provided in or in the region of the camera to cool operating parts of the camera or the lights of the camera.

7. A miniature TV camera system as claimed in Claims 5 and 6, in which the discharged fluid is bled from said bellows.

8. A miniature TV camera system as claimed in any preceding Claim, in which said fluid is air.

9. A miniature TV camera system as claimed in any preceding Claim, in which said connector accommodates fluid power lines, and rearwardly directed nozzles are provided at or in the camera to provide fluid jets to drive the camera forwardly through the conduit.

10. A miniature TV camera system as claimed in any preceding Claim, in which said connector is provided with an inflatable sheath at or adjacent to the camera to expand around and so centre and/or hold the camera in a conduit.

11. A miniature TV camera system as claimed in any preceding Claim, in which said connector comprises a hose-like member which accommodates services for operating the camera, said services including fluid power lines, and the end region of the member where the camera is mounted is provided with at least two opposed parts which are selectively expansible under fluid pressure to provide an articulating effect.

12. A miniature TV camera system having a TV camera substantially as hereinbefore described with reference to the accompanying drawings.

13. A miniature TV camera for a miniature TV camera system, as defined in any of the preceding Claims.

14. The features herein described, or their equivalents, in any patentably novel selection.