| 摘要 |
Noncoherent radiation, such as X-rays, is spatially coded, directed through an object and spatially detected to form a spatially coded pattern, from which an image of the object may be reconstructed. The X-ray source may be formed by X-ray fluorescence and subtraction of the holographic images formed by two sources having energy levels predominantly above and below the maximum absorption range of an agent in the object may be used to enhance contrast in the reproduced image. Constant spatial frequency coding of the source may be used to produce a spatial carrier frequency to enhance detection of low spatial frequency components of the spatially coded pattern so that images may be a more easily reconstructed such as the optical reconstruction of spatially code formed by the off-center section of a Fresnel zone pattern by converting the detected intensity pattern to a diffraction or phase pattern. |
