Photocharge is accumulated within an image sensor pixel array during a first exposure interval. At conclusion of the first exposure interval, accumulated photocharge is discarded from a first subset of the pixels to emulate absence of incident light with respect to those pixels. After discarding accumulated photocharge from the first subset of the pixels, first and second readout signals are generated, the first readout signals corresponding to respective pixels not included in the first subset and indicative of photocharge accumulated therein, and the second readout signals corresponding to respective pixels included in the first subset.