1. A method, comprising: receiving a visual image and an infrared (IR) image of a scene; for a portion of said IR image: extracting high spatial frequency content from a corresponding portion of said visual image; and combining said extracted high spatial frequency content from said portion of the visual image with said portion of the IR image, to generate a combined image, wherein the contrast and/or resolution in the portion of the IR image is increased compared to the contrast and/or resolution of said received IR image.