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mmero
Erode an image by a structuring element.

Synopsis

y = mmero( 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

mmero performs the erosion of the image f by the structuring element b. Erosion is a neighbourhood operator that compairs locally b with f, according to an inclusion rule. Since erosion 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([
   [1, 1, 1, 0, 0, 1, 1],
   [1, 0, 1, 1, 1, 0, 0],
   [0, 0, 0, 0, 1, 0, 0]])

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

              

              
>>> mmero(f,b)

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

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

              

              
>>> mmero(f,b)

              
array([[ 0,  0,  1,  2,  4,  4],
       [ 2,  2,  3,  0,  0,  0],
       [12, 12, 14, 14, 15, 16]],'b')

            

          

          

            

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

              

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

              

              
>>> b=mmimg2se(bimg)

              

              
>>> g=mmero(f,b)

              

              
>>> mmshow(f)

              

              
>>> mmshow(g)

              

              
>>> mmshow(g,mmgradm(f))

              

            

            

              
                

                  
                  
                  
                

                

                  f
                  g
                  
                

              
            

            

              
                

                  
                  
                

                

                  g,mmgradm(f)
                  
                

              
            

          

          
Gray-scale image:

          

            

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

              

              
>>> b=mmsedisk(3)

              

              
>>> mmshow(f)

              

              
>>> mmshow(mmero(f,b))

              

            

            

              
                

                  
                  
                  
                

                

                  f
                  mmero(f,b)
                  
                

              
            

          

        

      

    

    

      
Equation

      

        

          
Flat structuring element:

          

            
          

          
Non-flat structuring element:

          

            
          
Where

          

            
          

        

      

    

    

      
Source Code

      

        
def mmero(f, b=None):
    if b is None: b = mmsecross()
    y = mmneg(mmdil(mmneg(f),mmsereflect(b)))
    return y
    

      

    

    

      
See also

      

        

          
            

              mmfreedom
              Control automatic data type conversion.
            

            

              mmdil
              Dilate an image by a structuring element.
            

            

              mmimg2se
              Create a structuring element from a pair of images.
            

            

              mmsebox
              Create a box structuring element.
            

            

              mmsecross
              Diamond structuring element and elementary 3x3 cross.
            

            

              mmcero
              Erode an image conditionally.
            

            

              mmdist
              Distance transform.
            

            

              mmsesum
              N-1 iterative Minkowski  additions
            

          
        

      

    

    

      
See also

      

        

          
            

              mmfreedom
              Control automatic data type conversion.
            

            

              mmdil
              Dilate an image by a structuring element.
            

            

              mmsecross
              Diamond structuring element and elementary 3x3 cross.
            

            

              mmcero
              Erode an image conditionally.
            

            

              mmdist
              Distance transform.
            

          
        

      

    

    

      

        

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