An integrated circuit for an imaging system for imaging an object, the integrated circuit comprising: - an array of complementary metal-oxide-semiconductor, CMOS, optical sensors, each CMOS optical sensor comprising at least one pixel; and - an array of optical filters each configured to pass a band of wavelengths onto one or more of the CMOS optical sensors, the array of optical filters being directly postprocessed on the array of CMOS optical sensors by CMOS compatible fabrication steps, including deposition, patterning and etching; and - read out circuitry to read out pixel values from the array of CMOS optical sensors to represent an image of the object; wherein different ones of the optical filters being configured to have a different thickness, to pass different bands of wavelengths by means of interference, to allow detection of a spectrum of wavelengths, wherein the optical filters are arranged with thicknesses of the filters varying in a non-monotonic way from one side of the array to the other side and wherein the arrangement of the filters comprises clusters of overlapping spectral range, at least some of the CMOS optical sensors being arranged in a first group under the same one of the optical filters and at least some of the CMOS optical sensors being arranged in a second group under the same one of the optical filters, wherein the optical filter for the first group is different from the optical filter for the second group; and wherein at least part of the read out circuitry being for the first group and comprising at least two output circuits each coupled to different ones of the CMOS optical sensors of the first group, so that multiple pixels of the first group can be read out in parallel over the output circuits and at least part of the read out circuitry being for the second group and comprising at least two output circuits each coupled to different ones of the CMOS optical sensors of the second group, so that multiple pixels of the second group can be read out in parallel over the output circuits and in parallel with multiple pixels of the first group. - an array of complementary metal-oxide-semiconductor, CMOS, optical sensors, each CMOS optical sensor comprising at least one pixel; and - an array of optical filters each configured to pass a band of wavelengths onto one or more of the CMOS optical sensors, the array of optical filters being directly postprocessed on the array of CMOS optical sensors by CMOS compatible fabrication steps, including deposition, patterning and etching; and - read out circuitry to read out pixel values from the array of CMOS optical sensors to represent an image of the object; wherein different ones of the optical filters being configured to have a different thickness, to pass different bands of wavelengths by means of interference, to allow detection of a spectrum of wavelengths, wherein the optical filters are arranged with thicknesses of the filters varying in a non-monotonic way from one side of the array to the other side and wherein the arrangement of the filters comprises clusters of overlapping spectral range, at least some of the CMOS optical sensors being arranged in a first group under the same one of the optical filters and at least some of the CMOS optical sensors being arranged in a second group under the same one of the optical filters, wherein the optical filter for the first group is different from the optical filter for the second group; and wherein at least part of the read out circuitry being for the first group and comprising at least two output circuits each coupled to different ones of the CMOS optical sensors of the first group, so that multiple pixels of the first group can be read out in parallel over the output circuits and at least part of the read out circuitry being for the second group and comprising at least two output circuits each coupled to different ones of the CMOS optical sensors of the second group, so that multiple pixels of the second group can be read out in parallel over the output circuits and in parallel with multiple pixels of the first group.