Imaging apparatus
AssigneeEEV Limited
InventorChristopher John Morcom
Life of this patent
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Abstract
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.
Claims12
Imaging apparatus comprising:
- a solid state imager device including radiation sensitive detector elements;
- means for carrying out a threshold test;
- means for varying a threshold condition of the threshold test in accordance with changes in ambient conditions;
- and means for initiating image acquisition by said imager device when said threshold test is satisfied.
A dental X-ray imaging apparatus comprising:
- an X-ray source arranged in use to irradiate a subject;
- a solid state imager device for receiving X-ray radiation from said source after it has passed through said subject;
- means for initiating image acquisition when a threshold test is satisfied which incudes means for comparing a signal derived from said imager with a threshold condition;
- and means for varying said threshold condition in accordance with changes in ambient conditions.
Dependencies are inferred from the claim text.