[mmcero] [Up] [mmero] Dilations And Erosions

mmdil
Dilate an image by a structuring element.

Synopsis

y = mmdil( f, b = None )

Implemented in Python.

Input

f Image Gray-scale (uint8 or uint16) or binary image.
b Structuring Element

Default: None (3x3 elementary cross)

Output

y Image

Description

mmdil performs the dilation of image f by the structuring element b. Dilation is a neighbourhood operator that compares locally b with f, according to an intersection rule. Since Dilation is a fundamental operator to the construction of all other morphological operators, it is also called an elementary operator of Mathematical Morphology. When f is a gray-scale image, b may be a flat or non-flat structuring element.

Examples

Numerical examples
>>> f=mmbinary([
   [0, 0, 0, 0, 0, 0, 1],
   [0, 1, 0, 0, 0, 0, 0],
   [0, 0, 0, 0, 1, 0, 0]])

              
>>> b=mmbinary([1, 1, 0])

              

              
>>> mmdil(f,b)

              
array([[0, 0, 0, 0, 0, 1, 1],
       [1, 1, 0, 0, 0, 0, 0],
       [0, 0, 0, 1, 1, 0, 0]],'1')

              
>>> f=uint8([
   [ 0,   1,  2, 50,  4,  5],
   [ 2,   3,  4,  0,  0,  0],
   [12, 255, 14, 15, 16, 17]])

              

              
>>> mmdil(f,b)

              
array([[  1,   2,  50,  50,   5,   5],
       [  3,   4,   4,   0,   0,   0],
       [255, 255,  15,  16,  17,  17]],'b')

            

          

          
Binary image:

          

            

              
>>> f=mmbinary(mmreadgray('blob.tif'))

              

              
>>> bimg=mmbinary(mmreadgray('blob1.tif'))

              

              
>>> b=mmimg2se(bimg)

              

              
>>> mmshow(f)

              

              
>>> mmshow(mmdil(f,b))

              

              
>>> mmshow(mmdil(f,b),mmgradm(f))

              

            

            

              
                

                  
                  
                  
                

                

                  f
                  mmdil(f,b)
                  
                

              
            

            

              
                

                  
                  
                

                

                  mmdil(f,b),mmgradm(f)
                  
                

              
            

          

          
Gray-scale image:

          

            

              
>>> f=mmreadgray('pcb_gray.tif')

              

              
>>> b=mmsedisk(5)

              

              
>>> mmshow(f)

              

              
>>> mmshow(mmdil(f,b))

              

            

            

              
                

                  
                  
                  
                

                

                  f
                  mmdil(f,b)
                  
                

              
            

          

        

      

    

    

      
Equation

      

        

          
Flat structuring element:

          

            
          

          
Non-flat structuring element:

          

            
          
Where

          

            
          

        

      

    

    

      
Source Code

      

        
def mmdil(f, b=None):
    from Numeric import maximum, NewAxis, ones
    if b is None: b = mmsecross()
    if len(f.shape) == 1: f = f[NewAxis,:]
    h,w = f.shape
    x,v = mmmat2set(b)
    if len(x)==0:
        y = (ones((h,w)) * mmlimits(f)[0]).astype(f.typecode())
    else:
        if mmisbinary(v):
            v = mmintersec(mmgray(v,'int32'),0)
        mh,mw = max(abs(x)[:,0]),max(abs(x)[:,1])
        y = (ones((h+2*mh,w+2*mw)) * mmlimits(f)[0]).astype(f.typecode())
        for i in range(x.shape[0]):
            if v[i] > -2147483647:
                y[mh+x[i,0]:mh+x[i,0]+h, mw+x[i,1]:mw+x[i,1]+w] = maximum(
                    y[mh+x[i,0]:mh+x[i,0]+h, mw+x[i,1]:mw+x[i,1]+w], mmadd4dil(f,v[i]))
        y = y[mh:mh+h, mw:mw+w]
    return y
    

      

    

    

      
See also

      

        

          
            

              mmfreedom
              Control automatic data type conversion.
            

            

              mmcdil
              Dilate an image conditionally.
            

            

              mmero
              Erode an image by a structuring element.
            

            

              mmsebox
              Create a box structuring element.
            

            

              mmsecross
              Diamond structuring element and elementary 3x3 cross.
            

            

              mmimg2se
              Create a structuring element from a pair of images.
            

            

              mmsesum
              N-1 iterative Minkowski  additions
            

          
        

      

    

    

      
See also

      

        

          
            

              mmfreedom
              Control automatic data type conversion.
            

            

              mmsedil
              Dilate one structuring element by another
            

            

              mmcdil
              Dilate an image conditionally.
            

            

              mmero
              Erode an image by a structuring element.
            

            

              mmsecross
              Diamond structuring element and elementary 3x3 cross.
            

            

              mmimg2se
              Create a structuring element from a pair of images.
            

            

              mmsesum
              N-1 iterative Minkowski  additions
            

          
        

      

    

    

      

        

          
                    [mmcero]
                
                    [Up]
                    
                    [mmero]
                
          Python
        

        

          Copyright (c) 2003, Roberto A. Lotufo, UNICAMP-University of Campinas; Rubens C. Machado, CenPRA-Renato Archer Research Center.