Traditional filtered backprojection(FBP) method required complete projection data,which were often difficult or even impossible to acquire for objective reasons.
According to the theory of scalar diffraction, first, the equipollence of spatial distribution of the plane-wave interferential field and parallel projective sine grating is discussed.
Said image pair with parallactic information can also be inputted to the computer by scanning equipment or can be formed by adopting computer three-dimensional animation software.
An equalarea pseudo cylindrical projection gather is constructed, in which the longitudes are hyperbola being symmetrical to the central meridian and the latitudes are parallel lines.
The drawing method for the double channel impeller is studied.It is found that there is an in-conformity between the dimensions of plane-view and pinacoid-view of fluid cross-section.
As mentioned above in the directional lights section, the rendering of shadows for directional lights is an approximation that allows us to use a single render to cover a largeish area with shadows.