Automatic triggering of an intraoral x-ray sensor used in a dental x-ray imaging system. The intraoral sensor has an array of pixels. The array of pixels has a plurality of lines of pixels, and each of the pixels generates an electrical signal correlated to x-ray radiation that impinges that pixel. An electronic control unit is connected to the intraoral sensor to receive electric signals from the array of pixels. The electronic control unit destructively reads pixel clusters in one or more of the plurality of lines of pixels. The electronic control unit is configured to generate a dose-correlated signal based on the signals from each of the pixel clusters in each of the one or more lines of pixels and initiate capture of an image generated with information from each of the pixels in the array of pixels, when the combined signal exceeds a predetermined threshold.
