Two=dimensional optical modulation transfer function measurement - using coherent white noise diffuser and Fourier analysis of image

摘要

The modulation transfer function measurement device for parts of optical and photographic systems uses a coherent optical diffuser with a white noise characteristic or rectangular local frequency spectrum. An image of the diffuser is formed on a photographic material with a known modulation transfer function via the optical components under test. The two-dimensional modulation transfer function of these components is derived directly from the coherent optically produced Fourier Spectrum of the image. - For optical system applications the differ is matched to the component modulation transfer functions to produce an overall rectangular frequency spectrum. For photographic sheet material testing it is mounted in contact with the material. The diffuser is produced with the aid of a master diffuser and a filler with a transmissivity distribution corresp. to the inverse of the master filler frequency spectrum.