Comparison of MTF and Veiling-glare in the Assessment of the Infrared Optics

Abstract

The veiling-glare of infrared optical system as a figure of assessment is discussed. The veilingglare of germanium lenses, which have different surface roughness, were measured using the method proposed by author. Although the MTF's of the lenses obtained as Fourier transforms of line image distributions have no significant difference, the veiling-glare apparently vary in accordance with the surface roughness of lenses. The agreement of the veiling-glare with the contrast of images obtained through the lenses was very good, showing the usefulness of the veiling-glare for the assessment of infrared optical system.