The invention will be described with reference to a specific embodiment, which has been devised for use where a particular need exists, but the invention may find other applications.

In certain surgical situations, for example in endoscopic surgery, the surgeon requires to use both hands simultaneously to manipulate various instruments, but also requires to control the position of the endoscopic camera.

The present invention seeks to provide an arrangement that may be used by a surgeon to control an item such as a camera without moving his hands or feet.

According to one aspect of this invention there is provided an orientation detector arrangement, adapted to detect the orientation of a first component relative to a second component, wherein the first component comprises transmitter means adapted to transmit a plurality of diverging beams, each beam being uniquely identifiable, the second component comprising a detector, the detector being adapted to detect and distinguish the said beams transmitted by the transmitters.

Preferably each beam is a beam of light in or near the visible spectrum. Infra-red light is preferred.

Each beam may be transmitted with a different frequency, or may be pulse-code modulated in a unique way, but preferably each beam carries a signal generated by an oscillator, which oscillates at a unique respective frequency.

Conveniently the detector is adapted to detect the said beams and is associated with a plurality of tuned circuits, each tuned circuit being tuned to a frequency of a respective one of said oscillators.

Advantageously a signal generated from the detector is utilised to perform a control function.

Preferably the first component is provided with means to enable the first component to be worn on the head of a person.

Advantageously the first component comprises a housing provided with a head-band or strap.

Conveniently the receiver is provided on or adjacent a visual display unit or monitor.

Preferably the detector is associated with control means adapted to control the operation of a component which causes the image on the visual display unit or monitor.

Advantageously the control means controls a camera, the image from the camera being displayed on the visual display unit or monitor.

Conveniently the control means controls a component which is visible in the image as shown on the visual display unit or monitor, or which, when controlled, causes said image to change.

According to another aspect of this invention there is provided a control apparatus comprising a component adapted to be worn on the head of an operator, means to determine the position or orientation of said component and to generate a control signal in accordance with the position or orientation of said component.

Preferably the said component to be worn on the head of an operator is provided with means to emit signals, and said position or orientation determining means are adapted to receive said signals.

Conveniently the signals are emitted as diverging beams, the signals in each beam being unique, the position or orientation determining means being adapted to identify the beam or beams of the signals being received.

Advantageously the control means control the movement or function of a further device.

In one embodiment the further device is a camera, the position or orientation determining means being located on or adjacent a visual display unit or monitor adapted to display an image of the scene.

In an alternative embodiment the position or orientation determining means are located on or adjacent a visual display unit or monitor adapted to display an image of a scene viewed by a camera, the further device comprising a component which is visible within that scene.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which: FIGURE 1 is a perspective view of a first component in the form of a transmitter adapted to be worn on the head of a person, such as a surgeon, and FIGURE 2 is a part perspective and part diagrammatic view illustrating a visual display unit or monitor provided with sensors and an associated control arrangement.

Referring initially to Figure 1 of the drawings, a first component comprises a transmitter assembly which consists of a housing 1 associated with a band or strap 2, which is provided to enable the housing 1 to be secured to the head of a person, such as a surgeon. It is to be appreciated that the housing may be provided with any appropriate means to retain the housing in position and may be incorporat:ed into an appropriate surgeon's hat.

The front face 3 of the housing is provided with a plurality of transmitters. In the embodiment illustrated four transmitters 5, 6, 7, 8 are provided. The transmitters are adapted to transmit signals, the signals being directed along mutually diverging beams. In the embodiment illustrated, the beams 5',7' from the transmitters 5 and 7 are located on a substantially horizontal plane but are directed to diverge away from a centre line which extends perpendicularly from the housing 1. Similarly, the beams 6',8' from the transmitters 6 and 8, diverge downwardly and upwardly, respectively, from the centre line. The four beams illustrated thus mutually diverge away from each other.

The divergence of the beams has been substantially exaggerated in the drawings in order to facilitate an understanding of the invention. In a practical embodiment the beams would be much closer to being parallel than as presently illustrated.

Whilst, in the presently described embodiment of the invention, four transmitters are provided, it is to be appreciated that any appropriate number of transmitters may be provided to generate the diverging beams.

Each beam 5',6',7',8' will be of generally conical form.

Whilst the transmitters may transmit radiation of an appropriate frequency it is considered that the optimum form of transmitter comprises a transmitter which transmits light in or near the visible spectrum. The transmitters may comprise light-emitting diodes or lamps, and preferably emit infra-red light.

Each transmitter will be associated with appropriate means to form the respective conical beams discussed above. Thus, each transmitter may be associated with one or more lenses, or one or more shutters or irises.

The signal transmitted by each transmitter is different from the signal transmitted by the other transmitters. Thus, for example, each transmitter may transmit light of a different colour or wavelength.

Alternatively, each transmitter may transmit light which is pulse-coded in a unique manner. It is preferred, however, that each transmitter is driven by an oscillator of a different frequency. Thus, each beam carries a frequency which is unique to that beam.

It is to be appreciated, therefore, that the illustrated transmitter transmits four diverging beams, each of which is uniquely identifiable.

Figure 2 illustrates a visual display unit or monitor 9 provided with a detector 10 located adjacent the screen 11 of the visual display unit or monitor.

The detector 10 is adapted to detect the signal generated by the transmitters.

The detector may be an appropriate photo-sensor which is connected to means adapted to distinguish the signals transmitted from the transmitters. The distinguishing means may comprise filters responsive to the frequencies of the different colours of light transmitted, if this expedient is used, or digital means adapted to distinguish signals with different pulse-codings, if this distinguishing means is used. However, in the preferred embodiment, where the transmitters are driven by oscillators of different frequencies, the detector is associated with four tuned circuits 12, 13, 14, 15, which may comprise phase-locked loops, each tuned circuit being tuned to a respective one of the transmitter frequencies.

In the embodiment illustrated, the tuned circuits are connected to a control circuit 16 which is adapted to control an endoscopic camera 17. The endoscopic camera 17 is connected to provide an image on the screen 11.

It is to be understood that a surgeon using the arrangement described and illustrated will wear the housing 1 on his head in such a position that when the surgeon is looking directly at the screen 11 of the visual display unit or monitor 9, the centre line between the diverging beams is aligned with the detector 11. Because the beams diverge, the detector 11 will not receive any signal from any one of the transmitters 5, 6, 7 or 8.

Should the surgeon move his head, for example, towards the left, the beam 5' from the transmitter 5 will begin to impinge on the detector 11. The appropriate tuned circuit will generate an output which is fed to the control circuit 16. The control circuit 16 will be adapted to move the endoscopic camera to the left. Thus, by moving his head to the left, the surgeon will be able to control the movement of the camera, so that the camera moves to the left.

It is to be appreciated that should the surgeon move his head towards the right, the beam 7' from the transmitter 7 will be detected by the detector 10 and the appropriate tuned circuit will provide an output to the control circuit 16 causing the endoscopic camera to move to the right. A corresponding effect is experienced if the surgeon should move his head up or down.

If the beams 5', 6', 7', 8' have an appropriate divergence, where the beams reach the detector 10, the beams may, in certain regions, overlap.

In such a situation, should the surgeon move his head so as to observe, for example, the top left-hand corner of the screen, the detector 10 will detect a signal from the transmitter 5 and also from the transmitter 6.

The camera 17 may thus be controlled to move leftwardly and upwardly.

It is thus to be appreciated that by moving his head approprately, the surgeon may provide eight possible control signals to effect movement of the endoscopic camera.

Although the invention has been described, by way of example, as controlling an endoscopic camera, it is to be appreciated that an arrangement similar to that illustrated in Figures 1 and 2 may be utilised to control other items, such as a manipulator or a robotic device provided to assist a surgeon. The manipulator may manipulate an item that is visible in the image displayed on the visual display unit or monitor 9.

Whilst the invention has been described, by way of example, with reference to an apparatus intended for use by a surgeon, it is to be appreciated that the embodiments of the invention may find many other uses, especially where people have to perform complicated functions that require the use of both hands and where further control functions need to be carried out. It is envisaged that the invention may find other uses.

Whilst, in the described embodiment of the invention, the housing containing the transmitters is moved relative to the detector, it is to be appreciated that in alternative embodiments of the invention, the detector may move relative to the housing containing the transmitters.

As the detector moves from an initial position in which it is aligned with the centre line, the detector will receive the signal transmitted by one or more of the transmitters.

An appropriate control function can then be performed.

Such an embodiment is, of course, still relying on the fact that the orientation of the transmitter housing relative to the receiver is being detected.