Automatic region of interest function for image sensors

The present invention relates to reading-out sensor array pixels. In particular, the present invention provides an approach according to which only a region of interest with arbitrary geometry may be read out from the sensor array, thus leading to substantial time savings. In order to achieve this, a circuitry is provided for automatic determining of a ROI and reading out the ROI from the sensor array. The circuitry includes a fast reading-out circuitry which is less precise but faster than the accurate reading-out circuitry for reading-out the pixels of the sensor array. The fast reading-out circuitry reads out the pixels with low-level precision and determines by the processing of the fast read-out pixels the ROI which is then provided to an in-pixel ROI programming circuit for storing the ROI identification and by means thereof to the accurate reading-out circuit which then reads out only the pixels determined to belong to the ROI. The accurate read-out circuit is slower than the fast read-out circuit.