Three-Dimensional Reconstruction Of Computer Tomogram Using Computer Generated Holography

Computer tomography(CT) is one of the most widely used technologies in medicine, as a medical imaging tool, it has tremendous impact in noninvasive diagnosis and surgical operation. Besides, CT plays an important role in nondestructive testing in industry. However, CT represents only two-dimensional information but not three-dimensional information, which makes it necessary for doctors to use their experience and imagination to ascertain the very part that is ill. Therefore, synthesizing a series of two-dimensional CT images into three-dimensional images now has become a significant subject.Presently, there is some software that can stack a series of slices to a three-dimensional virtual object in a memory of the digital computer, and display it by computer graphics on the two-dimensional CRT. However, the parallax is not effective and the three-dimensional depth can not be perceived, so it is not real three-dimensional display but the projection of three-dimensional object on two-dimensional plane. In the same time, holography is the most perfect technique of three-dimensional display. Hologram can record visual information and recreate it exactly when suitably re-illuminated. So reconstructing three-dimensional CT images from a series of two-dimensional CT images using hologram is feasible.In this dissertation, two new methods for reconstructing three-dimensional CT images by computer generated holography is proposed. One is two-step rainbow holography combining computer generated holography and optical holography, the other is one-step rainbow holography using computer generated hologram(CGH).For the first method, the master hologram is designed and calculated by the way of computer generated holography; the reconstructed image from the master...