SobelKernel       691 Magick++/lib/Magick++/Include.h   using MagickCore::SobelKernel;
SobelKernel       974 magick/morphology.c     case SobelKernel:       /* these are defined using other kernels */
SobelKernel      1366 magick/morphology.c     case SobelKernel:
SobelKernel      1193 magick/option.c     { "Sobel", SobelKernel, UndefinedOptionFlag, MagickFalse },