An image sensor may include active pixel rows that are used to generate image signals in various modes of operation. The active pixel rows may receive control signals that have corresponding sets of transitions. These sets of transitions may occur during readout operations for some active pixel rows but not during readout operations for other active pixel rows, especially in the case where frames of multiple types are generated by the same pixel array in an interweaved manner. This can lead to different readout environments for readout operations corresponding to different active pixel rows due to control signal coupling effects. To mitigate these adverse effects, an image sensor may include dummy pixel rows that continuously pulse the sets of transitions during the readout operation of any active pixel row to ensure that the readout operations for all active pixel rows have the same readout environments.