An imaging sensor comprises: an array of light-detecting elements, wherein each light-detecting element in the array of light-detecting elements is arranged in the imaging sensor so as to detect a respective wavelength interval, wherein the respective wavelength interval differs for different light-detecting elements; a pattern arranged on the array of light-detecting elements, wherein the pattern defines a plurality of transparent areas, each transparent area being associated with a corresponding light-detecting element in the array of light-detecting elements, wherein a size of a transparent area among the plurality of transparent areas is dependent of the corresponding light-detecting element with which the transparent area is associated.