A single pixel sensor is provided, comprising a photo sensor configured to convert light into proportional signals; a charge storage configured to accumulate, repeatedly, a plurality of the signals converted by the photosensor; a first transistor coupled between a pixel voltage terminal and the photosensor; a second transistor coupled between the photosensor and the charge storage; and a readout circuit coupled between the charge storage and an output channel, wherein: the single pixel sensor is configured to carry out the repeated accumulations of signals multiple times per each readout by the readout circuit, the single pixel sensor is configured to synchronously convert reflections of light emitted by an associated illuminator or to convert light emitted by non-associated flickering light sources, and wherein the single pixel sensor is backside illuminated by the light.