Abstract: A delta image sensor comprising a plurality of acquisition circuits corresponding to at least one pixel. Each acquisition circuit includes at least one sensor circuit comprising a photosensor to generate a sensor signal, VSIG, depending on a light signal illuminating the photosensor; at least one single slope analogue to digital conversion, A/D, circuit configured to convert a current VSIG to a digital signal, wherein the A/D circuit (12) is configured to use one of a plurality of ramps for the conversion; at least one digital storage circuit configured to store a representation of at least one digital signal corresponding to a previous VSIG; at least one digital comparison circuit configured to compare the level of the stored representation with the current VSIG to detect whether a changed level is present; and at least one digital output circuit configured to generate an event output, in response to the changed level.

Abstract: An image sensor comprises an arrangement of pixels, the pixels including an acquisition circuit each, the acquisition circuit including: a sensor circuit configured to generate a sensor signal (VLOG) depending on a light signal illuminating a photosensor of the pixel; a storage circuit configured to store during a storage interval a stored signal (VSTORE) proportional to the sensor signal (VLOG); and a comparator circuit configured to generate after the refresh interval a comparator signal (VCOMP) depending on the sensor signal (VLOG) and the stored signal (VSTORE). A method of operating an image sensor comprises steps of generating a sensor signal (VLOG) depending on a light signal illuminating a photosensor of the pixel, storing during a storage interval a stored signal (VSTORE) proportional to the sensor signal (VLOG) and generating after the refresh interval a comparator signal (VCOMP) depending on the sensor signal (VLOG) and the stored signal (VSTORE).

Abstract: A delta image sensor comprising an arrangement of pixels and a plurality of acquisition circuits corresponding to at least one pixel. Each acquisition circuit includes at least one sensor circuit comprising a photosensor to generate a sensor signal, VSIG, depending on a light signal; at least one analogue to digital conversion, A/D, circuit configured to convert a current VSIG to a digital signal; at least one digital storage circuit configured to store a representation of at least one digital signal corresponding to a previous VSIG; at least one digital comparison circuit to compare the level of the stored representation with the current VSIG to detect whether a changed level is present; and at least one digital output circuit configured to generate an event output under the condition of the changed level. A digital representation may be externally written to the digital storage circuit of the at least one pixel.

Abstract: A delta image sensor comprising an arrangement of pixels and acquisition circuits corresponding to at least one pixel. Each acquisition circuit includes a sensor circuit comprising a photosensor to generate a sensor signal, VSIG, depending on a light signal illuminating the photosensor; at least one analogue to digital conversion, A/D, circuit configured to convert a current VSIG to a digital signal; at least one digital storage circuit configured to store a representation of at least one digital signal corresponding to a previous VSIG; a digital comparison circuit configured to compare the level of the stored representation with the current VSIG to detect whether a changed level is present; and a digital output circuit configured to generate an event output when the level has changed. The repeat rate of the analogue to digital conversion is chosen from one or more repeat rates corresponding to modulation of the light signal.