English Electric Valve Company Limited

Eev Limited

Christopher J Morcom

Kevin A Hadfield

In imaging apparatus particularly for use in intra-oral dental applications, a solid state imager is continually clocked out during a wait period prior to irradiation from an X-ray source. A signal derived from the CCD is compared with a threshold at to determine the onset of irradiation by the X-ray source which will appear as a rapid change in the signal level. The threshold conditions are varied to follow changes in ambient conditions and particularly temperature changes to allow for increase of dark current with a rise in temperature. This permits the threshold at which the CCD is triggered to begin image acquisition to be set at a relatively low level whilst minimising the risk of false triggering.

Imaging apparatus

Imaging apparatus includes an image sensor which is connected to a computer, or computer frame store, by an interface. The computer is arranged to generate control signals which are used to control the sequence of signals applied to the image sensor, thereby enabling the interface to be used with a plurality of different image sensor types.

Imaging apparatus with flexible interface for controlling different

A CCD image sensor is operated in an asynchronous mode to enable it to capture short lived events, or to freeze rapid motion. The image is acquired during an integration period which is triggered by a strobe pulse, and the resulting charge is held in a storage section of the CCD sensor until a regularly occuring field read-out period, during which the charge is read-out to constitute a video signal.

Method for operating an image sensor having an integration period

To determine some spatial characteristic, such as size or shape, of an object, the object is viewed with a television camera that employs an image sensor such as a CCD device. An image is formed on a television screen and a set of measurement markers (or cursors) are superimposed on the image at desired positions. The CCD timing signals are used to accurately determine the position of the cursors and hence the desired spatial characteristic.

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Maldon, United Kingdom

Christopher J Morcom