/* voxb_grayform.h --- erosion and dilation of PPV arrays. */
/* Last edited on 2021-07-02 21:32:35 by jstolfi */

#ifndef voxb_grayform_H
#define voxb_grayform_H

#define _GNU_SOURCE
#include <stdint.h>

#include <bool.h>
#include <ppv_array.h>
#include <ppv_brush.h>

ppv_array_t *voxb_grayform_compute(ppv_array_t *A, ppv_nbits_t bps, ppv_size_t ord);
  /* Computes the grayscale (local mean density) transform of the binary array {A}.
    
    The result is an array {G} with same number of dimensions {d} as {A}.
    There will be one voxel of {G} for every cubical block {B[ix]} of voxels of {A} with size
    {s = 2*ord+1} along every axis. The value of that voxel of {G[ix]} is the
    weighted average of the voxels of {A} around the center of {B[ix]},
    that is around the voxel {A[jx]} with index {jx[k] = s*ix[k] + ord} in each axis {k}.
    
    The average actually uses a Hahn (shifted cosine) window that extends
    {2*ord} voxels from {A[jx]} in every direction. */

#endif