Dave Mitchell's DigitalMicrograph™ Scripting Website

These tyype of image processing tools are described in John Russ' 'The Image Processing Handbook'.

// Filter to compute a Mexican Top Hat Filtered Image

// Note - this is a slow operation.

// Dave Mitchell, nospamadmin@dmscripting.com (remove the nospam to make email address this work)

// March 2003

// version:20030301

// v2.0

// Variables

realimage front

front:=getfrontimage()

showimage(front)

setwindowposition(front,142,24)

updateimage(front)

string unitstring

number scalex, scaley

getunitstring(front, unitstring)

getscale(front, scalex, scaley)

number xsize=0, ysize=0

getsize(front,xsize,ysize)

string name = getname(front)

string newname = "7x7 Mex Hat of " + name

if(len(newname)>31) newname=left(newname,31)

number adderx, addery

number pixelvalue=0

number counter=0

image kernel

image sumimage:=integerimage(newname, 4,1, xsize, ysize)

sumimage=0

// Definition of a 7x7 Mexican Hat Kernel

kernel := [7,7]:

{

{0,0,-1,-1,-1,0,0 },

{0,-1,-3,-3,-3,-1,0 },

{ -1,-3,0,7,0,-3,-1},

{ -1,-3,7,24,7,-3,-1},

{-1,-3,0,7,0,-3,-1},

{ 0,-1,-3,-3,-3,-1,0},

{0,0,-1,-1,-1,0,0 }

}

sumimage=Exprsize(xsize,ysize,0)

// Obtain the values from the kernel image

For (adderx=1; adderx<8;adderx++)

{

For(addery=1;addery<8;addery++)

{

pixelvalue=getpixel(kernel, adderx-1, addery-1)

sumimage=sumimage+(offset(front,adderx-4,addery-4)*pixelvalue)

counter=counter+1

openandsetprogresswindow("Working on:","X Pass "+adderx+" of 7","Y Pass "+addery+" of 7")

}

}

showimage(sumimage)

setwindowposition(sumimage,170,54)

converttoshort(sumimage)

openandsetprogresswindow("","","")

setscale(sumimage,scalex,scaley)

setunitstring(sumimage,unitstring