An imaging system comprises an image pixel array, a dark pixel array, and a controller. The image pixel array includes a plurality of pixel clusters adapted to generate image signals. The dark pixel array is adapted to generate one or more black reference signals corresponding to a global black level value of the imaging system. The controller includes logic that when executed by the controller causes the system to perform operations including determining local black level values for each of the pixel clusters and correcting a first image signal included in the image signals based, at least in part, on the global black level and a first local black level value included in the local black level values.