| 摘要 |
In imaging apparatus particularly for use in intra-oral dental applications, a solid state imager 3 is arranged to detect X-ray radiation from a source 1 after passing through an object 2. Prior to irradiation by the source 1, charge accumulated in the elements 4 of the CCD 3 is clocked from two or more rows into a register 5 such that charges are summed. The register 5 is output via a charge amplifier 6 which sums the charge applied to it to give a relatively large output signal which is amplified at 9 and applied to thresholder 9. Onset of X-ray irradiation is detected when the signal applied to the thresholder 9 exceeds a reference level. A start signal is then transmitted to a control unit 8 to cause image acquisition to begin. <IMAGE> |
