In response to objects having relative motion within an encoding/sensing region relative to an encoder/sensor that, e.g., photosenses emanating light or performs impedance-based sensing, sensing results can indicate sensed time-varying waveforms with information about the objects, about their relative motion, about excitation characteristics, about environmental characteristics, and so forth. An encoder/sensor can include, for example, a non-periodic arrangement of sensing elements; a longitudinal sequence of sensing elements with a combined sensing pattern that approximates a superposition or scaled superposition of simpler sensing patterns; and/or IC-implemented sensing elements that include photosensing arrays on ICs and readout/combine circuitry that reads out photosensed quantities from cells in groups in accordance with cell-group sensing patterns and combines the readout photosensed quantities to obtain the sensing results. Objects can move fluidically as in flow cytometry, through scanning movement as in document scanning, or in other ways.