A processing system for plate-like objects is provided, with an exposure device and an object carrier with an object carrier surface for receiving the object. The exposure device and the carrier are movable relative to one another, such that the exact position of the object relative to the carrier is determinable. An edge detection device is provided which comprises at least one edge illumination unit having an illumination area, within which an object edge located in the respective object edge area has light directed onto it from the side of the carrier. At least one edge image detection unit is provided on a side of the object located opposite the carrier, the edge image detection unit imaging an edge section of the object edges located in the illumination area as an edge image, such that the respective edge image is detectable in its exact position relative to the carrier.