A device and method for the hardware detection of local edges in an image, comprised of a plurality of elemental cells for mixed signal processing, locally interconnected with each other, comprising in each cell a first switch configured to enable the pre-charging of a condenser at the supply voltage; and where once said condenser is pre-charged, it discharges via a second switch connected to a power source which varies in a monotonically increasing manner with the analog voltage representing the value of the pixel concerned; and where the value of the pixel is compared asynchronously with the neighboring pixels of the neighboring cells via two inverters, a digital NOR gate, a digital NAND gate, a third and fourth switch and a memory feature to store the result.