MAKE_CUBE
Keywords: greg

Next: MAP_AVER Up: Image Processing Tasks Previous: INTERPOLATE Contents Index

##
MAKE_CUBE

            MAKE_CUBE

        This  is  an  image  construction  task  which  is  able  to  produce  a
        filled image from one containing many blanked pixels.  The reconstructed
        filled image is not constrained to fit exactly the observed data points.
        On  the  opposite, the construction is made by the analogy to a flexible
        plate attached to fixed points by springs:  the plate is  the  analogous
        of  the  surface  represented by the image, and the fixed points are the
        analogous of the observed data points.  By adjusting the parameter P
                              P = (plate stiffness) / (springs stiffness)
        it is possible to control the fidelity to  the  original  data  and  the
        amount of smoothing involved in the image reconstruction.  Low values of
        P mean  high  fidelity  to  observed  data,  and  negligible  amount  of
        smoothing.

        The original grid is first expanded by  a  factor  EXPANSION$,  new pix-
        els   being   attributed   the  blanking  value.  Then, the minimization
        proceeds iteratively to adjust the final  image,  until  convergence  is
        reached.   Initially  blanked  pixels  are  ignored  in  the convergence
        criterium.

        The algorithm works on cubes, processing each plane  independently.   It
        can  be  used as an alternative to FILL_CUBE for oversampled images, but
        works also for undersampled data.