contrib/tbl/vepl1/vepl1_threshold.cxx

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// This is tbl/vepl1/vepl1_threshold.cxx
#include "vepl1_threshold.h"
#include <vcl_iostream.h>
#include <vipl/accessors/vipl_accessors_vil1_image.h>
#include <vipl/vipl_threshold.h>
#include <vil1/vil1_memory_image_of.h>
#include <vil1/vil1_rgb.h>
#include <vxl_config.h> // for vxl_byte

vil1_image vepl1_threshold(vil1_image const& image, double threshold, double below, double above)
{
  // byte greyscale
  if (vil1_pixel_format(image) == VIL1_BYTE) {
    vil1_memory_image_of<vxl_byte> mem(image); // load in memory to pass to filter
    vil1_memory_image_of<vxl_byte> out(image);
    vipl_threshold<vil1_image,vil1_image,vxl_byte,vxl_byte> op(vxl_byte(0.5+threshold), vxl_byte(0.5+below), vxl_byte(0.5+above));
    op.put_in_data_ptr(&mem);
    op.put_out_data_ptr(&out);
    op.filter();
    return out;
  }

  // byte rgb: process colour bands independently as ubyte images
  else if (vil1_pixel_format(image) == VIL1_RGB_BYTE)
  {
#define r_g_b vil1_rgb<vxl_byte> // cannot use typedef since that may cause ambiguous overload problems
    vil1_memory_image_of<r_g_b > in(image); // load in memory to pass to filter
    vil1_memory_image_of<r_g_b > out(image);
    vil1_memory_image_of<vxl_byte> mem((vxl_byte*)(in.get_buffer()),3*in.width(),in.height()); // reinterpret as vxl_byte
    vil1_memory_image_of<vxl_byte> mout((vxl_byte*)(out.get_buffer()),3*in.width(),in.height());
    vipl_threshold<vil1_image,vil1_image,vxl_byte,vxl_byte> op(vxl_byte(0.5+threshold), vxl_byte(0.5+below), vxl_byte(0.5+above));
    op.put_in_data_ptr(&mem);
    op.put_out_data_ptr(&mout);
    op.filter();
    return out;
  }

  // 16-bit greyscale
  else if (vil1_pixel_format(image) == VIL1_UINT16) {
    vil1_memory_image_of<vxl_uint_16> mem(image); // load in memory to pass to filter
    vil1_memory_image_of<vxl_uint_16> out(image);
    vipl_threshold<vil1_image,vil1_image,vxl_uint_16,vxl_uint_16>
      op(vxl_uint_16(0.5+threshold), vxl_uint_16(0.5+below), vxl_uint_16(0.5+above));
    op.put_in_data_ptr(&mem);
    op.put_out_data_ptr(&out);
    op.filter();
    return out;
  }

  // float
  else if (vil1_pixel_format(image) == VIL1_FLOAT) {
    vil1_memory_image_of<float> mem(image); // load in memory to pass to filter
    vil1_memory_image_of<float> out(image);
    vipl_threshold<vil1_image,vil1_image,float,float> op((float)threshold, (float)below, (float)above);
    op.put_in_data_ptr(&mem);
    op.put_out_data_ptr(&out);
    op.filter();
    return out;
  }

  // double
  else if (vil1_pixel_format(image) == VIL1_DOUBLE) {
    vil1_memory_image_of<double> mem(image); // load in memory to pass to filter
    vil1_memory_image_of<double> out(image);
    vipl_threshold<vil1_image,vil1_image,double,double> op(threshold, below, above);
    op.put_in_data_ptr(&mem);
    op.put_out_data_ptr(&out);
    op.filter();
    return out;
  }

  //
  else {
    vcl_cerr << __FILE__ ": vepl1_threshold() not implemented for " << image << vcl_endl;
    return 0;
  }
}