Abstract: An image sensor includes an array of pixels on a semiconductor device for sensing light incident on the pixel array and a plurality of anomaly registers comprising a plurality of nonvolatile elements. Each anomaly register identifies an anomalous pixel cluster and includes a location indicator with a row and column address and a size indicator with a horizontal and vertical range. In other embodiments, each anomaly register includes a first address, second address, first direction flag, and second direction flag. The first and second direction flags use a first state to indicate a row address or a second state to indicate a column address. The first and second direction flags combine to define an anomalous pixel cluster, a pair of anomalous pixel rows, or a pair of anomalous pixel columns. Some embodiments may include an anomaly type indicator and some embodiments may include a shape indicator.