GB2336688A

GB2336688A - On-film camera identification

Info

Publication number: GB2336688A
Application number: GB9808598A
Authority: GB
Inventors: William George Imlah; Richard Anthony Kirk
Original assignee: Canon Research Centre Europe Ltd
Current assignee: Canon Technology Europe Ltd
Priority date: 1998-04-22
Filing date: 1998-04-22
Publication date: 1999-10-27
Also published as: GB9808598D0

Abstract

A photographic apparatus has a coded means (7) adapted to provide an identification of the camera. The coded means allows a light sensitive medium (10) to carry coded indicia individual to the camera by utilising image light passing through the optical system of the photographic apparatus so as to expose the light sensitive medium to both the image and to the coded indicia. The coded means may be a focal plane plate with a coded sequence of notches.

Description

2336688 1 PHOTOGRAPHIC APPARATUS IDENTIFICATION is The present invention

concerns photographic apparatus and is particularly, though not exclusively, concerned with providing cameras with means which enable individual cameras to be readily identified. Modern cameras are frequently extremely sophisticated and thus expensive. Additionally, they are compact and are often used in environments where the user is out in the open and is constantly on the move. As a result it is a common occurrence for cameras either to be mislaid or stolen. It is accordingly desirable to provide a means whereby an individual camera can be readily identified. This would also provide, if the camera had not been stolen, a link to the person who took the photograph.

Such a means are disclosed in US Patent Specification No US-A-4123767. This specification discloses a system in which each camera is provided with an internal closed chamber housing a lamp. One wall of the chamber is transparent and carries indicia which identify the camera. When the lamp is turned on the light from the lamp modified by a portion of the film which is focused light from the cameras exposed film causes the indicia identified from the exposed film at each exposure.

the indicia illuminates not illuminated by the lens system. Thus the and the camera can be The lamp is turned on 2 However, this arrangement has the problems that it is relatively complex. Additionally failure of the lamp, or its removal, mean that the exposed film will carry no identifying marks.

The present invention is concerned with the problem of providing a means whereby individual cameras can be rapidly recognised in accordance with a standard procedure.

In accordance with the present invention there is provided a camera having coded means adapted to provide an identification for the camera, the coded means being adapted to cause a film exposed by the camera to carry a plurality of markings individual to the camera, a photographic apparatus having coded means adapted to provide an identification of the camera, the coded means being adapted to cause a light sensitive medium exposed by operation of the lens system of the camera to carry coded indicia individual to the camera, and characterised in that the coding means are adapted to utilise image light paving through the optical system of the photographic apparatus so as to expose the light sensitive medium to both the image and to the coded indicia.

The result of such a signature is that the detection of a stolen camera could easily be carried out at processing labs. The labs could routinely check the camera ID against an open database listing cameras and 3 their users addresses. This would let them return originals to their owners even when all other identifying data is mislaid or destroyed. Even when the return address is known, this might save the operator entering 5 the address manually.

In order that the present invention may be more readily understood, an embodiment thereof will now be described by way of example and with reference to the accompanying drawings, in which:

Figure 1 is a rear view of a typical camera showing the backplate of the camera removed.

The camera has a main body 1, an eyepiece 2 through which a user views the scene to be photographed and suitable control buttons indicated at 3. These buttons are indicated by way of example only and can comprise a button for triggering an exposure, a button for setting whether the camera is to be used with f lash or not, whether pictures are to be panoramic or not or any of the other features which are associated with modern cameras.

The camera shown in Figure 1 is provided with a pivoted backplate only part of which is indicated at 4 and this backplate when in the open position as shown in the figure exposes a chamber 5 for holding a film cassette (not shown). As is well known in operation of the camera the film is advanced stepwise by suitable chosen sprockets through the focal plane of the imaging system of the camera to be exposed. As this is entirely 4 conventional it will not be described in detail. In the camera shown in Figure 1 the f ilm to be exposed is advanced past a f ocal plane plate shown at 6 which divides the lens system of the camera f rom the actual film. The focal plane plate 6 has an aperture 7 through which light from the lens system of the camera passes to expose the film.

Figure 2 of the drawings shows a film 10 passing at a greatly exaggerated distance from the focal plane plate 6 and in front of aperture 7. In both Figures 1 and 2 it will be seen that the edges of the aperture 7 in the focal plane plate 6 are notched.

The notches shown in the drawings are much larger than would be required in a real system but have been shown in this manner in the interest of clarity.

A 35 mm. print has 2 x (24+36) mm or 12 cm of border.

Even with a 1000 ASA film it should be possible to get more than 4 bits/per mm by notching the aperture in such a manner. Naturally the notches exposed on the film would not affect the printed image but by notching the border of the aperture as described it is possible to code approximately 50 bytes of information. Thus it should be possible to f it the name and address of the owner of the camera within the amount of code available.

Alternatively, or additionally, it is possible to make the code represent a serial number which can be encoded in such a manner that a thief cannot make another valid code by removing bits from the code.

The manner in which the information is coded can of course be varied. Notches of different shapes could represent different values. Additionally each edge of the aperture could represent a particular binary member with the position of a notch along the edge representing either a 1 or a 0.

As the present invention is likely only to be used with relatively expensive cameras it will frequently be found that such cameras are used by professional photographers. It may also be desirable to provide the edge of the aperture 7 with a version of international copyright symbol which would appear on each photograph along with the code. This could prove a strong link to the photographer who actually took the photograph if, as in the case of professional photography, the picture has high monetary value.

It is of course possible to provide the focal plane plate 6 with, instead of notches, small holes or even a partially cut-out representation of the owner, s signature surrounding the rim of the aperture. The position of the holes would, as in the case of the notches, be individual to each particular camera.

Figures 3 and 4 of the drawings show two examples as to how the notched codes can be varied.

It will be appreciated that what has been disclosed is both simple in application and difficult to remove.

6 It is of course possible for the coded information to be introduced into the focused image light earlier in the optical path of the camera. Suitable indicia may be, f or example, included on one of the lenses in the lens system of the camera or on one of the prisms which form part of the optical system of reflex cameras.

7

Claims

1. A photographic apparatus having coded means adapted to provide an identification of the camera, the coded means being adapted to cause a light sensitive medium exposed by operation of the lens system of the camera to carry coded indicia individual to the camera, and characterised in that the coding means are adapted to utilise image light passing through the optical system of the photographic apparatus so as to expose the light sensitive medium to both the image and to the coded indicia.

2. A photographic apparatus according to claim 1, wherein the photographic apparatus is a camera which includes a focal plane plate along which the light sensitive medium in the form of a film passes during successive exposures of the film, and wherein the focal plane plate includes a coded sequence of openings through which light can pass to expose the f ilm so as to generate said coded indicia.

3. A camera according to claim 2, wherein the openings are a plurality of notches formed in the periphery of the aperture in the focal plane plate.

4. A camera according to any preceding claim wherein 8 the indicia includes the international copyright symbol.

5. A camera having means for identifying the camera substantially as hereinbefore described with reference to the accompanying drawings.