The invention relates to an image sensor with N rows of P active photosensitive pixels using MOS technology. The sensor comprises digitizing circuits organized with N rows of P processing circuits, each processing circuit of row rank i and of column rank j comprising a respective sampler for carrying out a correlated double sampling of the signals present on a column conductor of rank j and corresponding to the observation of an image dot over the same integration time for all the rows, and an analog-digital conversion means in order to supply digital values of the analog signals sampled. The sensor is particularly suited to operating in TDI (image scanning and integration) mode.