Feldkamp cone-beam algorithm

The system is ideal for examining the rearrangement of microstractural composition of soft-solid materials with variation in temperature. An example of a material that is practically impossible to image in the natural state by conventional optical microscopy is shown in (Fig. 26.58a). The volumes depicted are child volumes, containing a region of interest (ROl), extracted fipom the reconstruction of a frozen four-phase soft-solid structure. The reconstructed volume is derived from 720 filtered and back-project frames using the Feldkamp cone-beam algorithm, with a resolution of 512 X 512 pixels per frame. 

L.A. Feldkamp, L.C. Davis, J.W. Kress Practical Cone-Beam Algorithm... 

Feldkamp LA, Davis LC, Kress JW (1984) Practical cone-beam algorithm. J Opt Soc Am A 612-619... 

The scanning schemes that have been adapted to the above principle may involve the spiral/ helical motion that requires lateral displacement with rotation. Extensions of the Feldkamp algorithm, for quite general three-dimensional scaiming loci, have been developed by Wang et al. For further discussions on the approximate and accurate cone-beam reconstruction the reader is referred to Ref. 17. 

From a mathematical point of view, 1 and 2 enforce approximate reconstruction techniques. The standard approach for this type of cone-beam tomography is the so-called Feldkamp algorithm. 

---