GB2144009A - A combined TV and photographic camera - Google Patents

Abstract

A combined TV and photographic camera comprises a TV camera imaging device 5 located behind an optical system 1 for focusing a desired image onto the imaging device. A film transport means provided within a container 8 feeds a length of photographic film through an image plane of the optical system whereby a frame of the film can be exposed with the desired image. By employing photographic film having alternate exposable frame regions 13 and transparent window portions 12, the desired image can either be exposed on a frame of the film or be viewed by the TV camera imaging device. The combined camera can be employed in a remote TV inspection system for inspecting e.g. boiler tubes or gas mains, wherein the TV camera imaging device is connected to a user operated central control unit and the film can be transported under operation of the control unit. The optical system 1 can comprise an adjustable focusing lens system. <IMAGE>

Description

SPECIFICATION A combined tv and photographic camera This invention relates to combined TV and photographic cameras and in particular to those suitable for operating in small dimension pipes or the like.

Remote TV inspection systems allow observation and recording of situations where it is physically hazardous or impossible for a human being to reach. For example, in monitoring of the condition of boiler tubes or gas mains, the physical dimensions often prohibit manual entry. Therefore a remote TV inspection system can be employed.

Preferably such a system uses colour TV cameras since colour allows better discrimination between objects. However, colour TV cameras are bulky and as the physical dimensions of the situation of usage reduce it is necessary to resport to the smaller black and white TV cameras. Nevertheless in both cases the resolution of the TV picture is limited and for definitive observation of a particular situation a colour photographic picture is greatly preferred due to its inherent better resolution.

Known combined TV and photographic cameras for use in such a remote inspection system employ a single lens reflex photographic camera with a TV camera viewing through its viewfinder. However as the dimensions of a situation where the system is to be employed are reduced the necessity to use in the photographic camera a small reflex mirror of special manufacture involves considerable expense, and ultimately the situation dimensions reduce to a point where such single lens reflex cameras are not manufactured.

it is an object of the invention to provide a combined TV and photographic camera obviating the necessity to employ a single lens reflex photographic camera.

According to one aspect of the invention there is provided a combined TV and photographic camera comprising a TV camera imaging device, an optical system for focusing a desired image onto the imaging device, and film transport means for feeding a length of photographic film through an image plane of the optical system whereby a frame of the film can be exposed with the desired image, the camera being suitable for use with photographic film having alternate exposable frame regions and transparent window portions through which portions the desired image can be view by the TV camera imaging device. By employing photographic film having alternate exposable frame regions and transparent window portions it is only necessary to use a single conventional optical system without recourse to a single lens reflex mirror or other complex lens arrangement.The film can be transported to a window portion to allow viewing of the desired image by the TV camera imaging device or the film can be transported to an exposable frame region to allow a photograph of the desired image to be obtained. Preferably the image plane is located between an objective lens of the optical system and the imaging device. In order to ensure that the length of photographic film fed through the image plane is planar the image plane can be sandwiched between pla nar transparent plates.

In a preferred embodiment the combined camera includes film storage means located behind the TV camera imaging device relative to the optical system and includes light-proof film guides located on opposite sides of the imaging device and extending between the film storage means and the image plane. By location of the film storage means behind the TV imaging device and by having such lightproof film guides it is possible to produce a thin elongate combined TV and photographic camera capable of being employed in small dimensions pipes or the like, the limiting factor on the camera dimension being the diameter of the optical system and the TV imaging device. Conveniently the film transport means is included inside the film storage means and comprises an oblate shaped endless ring capable of movement in a direction along the ring and adapted to grip a portion of the film.This allows a compact structure transport means.

The combined camera preferably includes first light means capable of producing a desired image suitable for viewing by the TV camera imaging device and second light means capable of producing a desired image suitable for exposing the photographic film. In some instances it is preferable that the optical system includes shutter means capable of preventing the desired image from reaching hhrough to the image plane. Clearly the optical system can include a zoom lens.

According to another aspect of the invention there is provided a remote TV inspection system including a combined TV and photographic camera as described above wherein the TV camera imaging device is connected to a user operated central control unit and wherein the film transport means is connected to and operated by said control unit.

In a preferred embodiment the optical arrangement comprises an adjustable focusing lens system and means to alter the focus thereof which is connected to and operated by the control unit. In this way a remote TV inspection system can be constructed which is capable of entry into small dimension pipes and can take photos or monitor the environment with a TV system. By employing an adjustable focusing lens system the focus of the combined camera can be remotely altered.

According to a still further aspect of the invention there is provided a photographic film strip having alternate exposable frame regions and transparent window portions.

Examples of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 illustrates an internal view of a combined TV and photographic camera embodying the invention.

Figure 2 illustrates a strip of film suitable for use with the combined TV and photographic camera shown in Figure 1.

Referring to Figure 1 ,an outer sleeve and control leads and circuitry for the combined camera are not shown for the purposes of clarity. In practice the camera has a rigid construction and is contained preferably within a rigid outer sleeve. The combined camera as shown in Figure 1 comprises an optical system 1 which is arranged to view an object. The desired image of the object is focused onto a screen arrangement 3 held in spaced relation from the optical system by supports 2. The lens system can comprise any suitable lens, for example of fixed focal length or a zoom lens. The lens chosen is dependent on the dimension restrictions imposed by the proposed use of the combined camera.

The screen arrangement 3 comprises two transptrent plates, such as glass, between which is fed a strip of photographic film 20 illustrated in Figure 2. The plates act to ensure that the film is planar with respect to the desired image. In practice the plates could be removed so that the frame is free standing. It will be apparent that the desired image occurs at an image plane of the optical system. As shown in Figure 2 the strip of film comprises alternate exposable frame regions 1 3 and transparent window portions 12, the exposable frame regions being coated with a suitable film emulsion.

A TV camera 5 is located opposite the optical system and the TV lens arrangement 4 is focused at where the desired image will fall on the screen arrangement. Consequently when a transparent window portion of the film is located in the screen arrangement the desired image, viewed through the film, is focused onto an imaging device contained within the TV cameras.

The film strip is supplied to the screen arrangement through light-proof film guides 6 and 7 running along opposite sides of the TV camera. In the embodiment shown the guides are aligned parallel to the optical axis linking the optical system 1 and the TV camera 5 and are located at the surface of the TV camera.

The guide 6 is connected to a wind-on spool 9 located within a light tight film storage box 8 provided behind the TV camera and the guide 7 is connected to a supply spool 10 also provided within the container 8.

The guides extend along the TV camera surface to the screen arrangement so that a portion of film is located at the screen arrangement. It will be apparent that the spools 8 and 9 could be provided within separate boxes and each spool could be replaced by an oblate endless ring, such as a caterpillar tread, which includes lugs adapted to locate with guidc holes 11 provided in the film 20. In this way a thin combined TV and photographic camera for use in small dimensions can be constructed. It will be apparent that the guides and associated spools and film storage container could be providcd adjacent the screen arrangement if the dimensions in which the combined camera was to be used were suitable.

Therefore the combined TV and photographic camera can either allow viewing of the image at the screen arrangement by the TV camera when a transparent portion of the film is sandwiched between the plates or alternatively when the strip of film is wound on such that an exposable frame region is sandwiched between the plates the desired image causes a reaction with the emulsion on the frame so that a photograph of the image is taken.

Clearly the taking of the photograph requires exposure of the emulsion on the frame to the correct quantity of light. This can be achieved either by use of a shutter means capable of preventing the desired image from falling on the screen arrangement or by having the object in complete darkness and providing suitable flashlight means. In use when the photo has been exposed by the flashlight means the film can be wound onto the next transparent window portion and the object illuminated for the TV camera by suitable TV lighting means. When it is again desired to photograph the object, the TV lighting means can be extinguished, the film wound on to a further exposable frame region and the flashlight means activated again. Typically such an arrangement can be used in many remote inspection systems since the objects to be viewed are often enclosed and hence in darkness.

The above described combined TV and photographic camera is suitable for use in a remote TV system for examining a pipe intcrior, say. It is known in the art for the flash and TV lighting systems to be connectcd to a user operated central control unit to permit remote activation thereof. In addition, the film can be wound on by the provision of suitable remote controlled film transport means. Furthermore it is known to have adjustable optical systems, for example a zoom lens, wherein the focusing thereof can be remotely altered. It will be apparent that all connections and circuitry for such remote functions are not shown in the figures for reasons of clarity.

Therefore the interior of a pipe which is in complete darkness can be viewed with a TV camera and when a point of interest is located a picture thereof can be obtained before viewing again by the TV camera.

Preferably, the glass plates of the screen arrangement have ground surfaces. In cases when the T.V. camera viewing lens has a very short local length (24 mm say), the small depth of focus may cause some problem with columniation. Consequently, it can be desirable to provide a means to move the lens system automatically forward by a distance equal to the thickness of the film for taking a picture and returning the lens to its original position for viewing through the transparent frame. Any suitable remote means for producing the slight movement can be employed.

Consequently, a combined TV and photographic camera is achieved which does not require a single lens reflex camera. It is therefore possible to construct a combined camera having an outer diameter of 65 mm which is of particular use in interior study of nuclearreactors where entry is only possible through fuel channels having a diameter of 75 mm.

This combined camera employs colour and/or black and white photographic film and a TV camera. It is known to have black and white TV cameras of diameter 38 mm and it is therefore possible to construct a combined TV and photographic camera embodying the invention which has a diameter not much greater than 38 mm. The combined TV and photographic camera also has applications in pipe inspection for welds and corrosion, and down boiler tubes for examination of pitting.

Claims (14)

1. A combined TV and photographic camera comprising a TV camera imaging device, an optical system for focusing a desired image onto the imaging device, and film transport means for feeding a length of photographic film through an image plane of the optical system whereby a frame of the film can be exposed with the desired image, the camera being suitable for use with photographic film having alternate exposable frame regions and transparent window portions through which portions the desired image can be viewed by the TV camera imaging device.

2. A combined camera as claimed in claim 1 wherein said image plane is located between an objective lens of the optical system and said imaging device.

3. A combined camera as claimed in claim 1 or 2 wherein said image plane is sandwiched between planar transparent plates.

4. A combined camera as claimed in any preceding claim including film storage means located behind the TV camera imaging device relative to the optical system and also including light-proof film guides located on opposite sides of the imaging device and extending between the film storage means and said image plane.

5. A combined camcra as claimed in claim 4 wherein said film transport means is provided within the film storage means and comprises an oblate shaped endless ring capable of movement in a direction along the ring and adapted to grip a portion of the film.

6. A combined camera as claimed in any preceding claim including first light means capable of producing a desired image suitable for viewing by the TV camera imaging device and second light means capable of producing a desired image suitable for exposing the photographic film.

7. A combined camera as claimed in any preceding claim wherein the optical system includes shutter means capable of preventing the desired image reaching the image plane.

8. A combined camera as claimed in any preceding claim wherein the optical system includes a zoom lens.

9. A remote TV inspection system including a combined TV and photographic camera as claimed in any preceding claim wherein the TV camera imaging device is connected to a user operated central control unit and wherein the film transport means is connected to and operated by said control unit.

1 0. A remote TV inspection system as claimed in claim 9 wherein the optical system comprises an adjustable focusing lens system and means to alter the focus thereof which is connected to and operated by said control unit.

11. A photographic film strip having alternate exposable frame regions and transparent window portions.

1 2. A combined TV photographic camera substantially as herein described with reference to the accompanying drawings.

1 3. A remote TV inspection system substantially as herein described with reference to the accompanying drawings.

14. A photographic film strip substantially as herein described with reference to the accompanying drawings.