Demonstrates image processing.

------------------------------------------------------------------------
See also CannyEnhancer, GaussianDerivative, HysteresisThreshold,
NonMaxSuppression, ColorMapGrayScale, Imager, ReadImage
------------------------------------------------------------------------

Contents

------------------------------------------------------------------------- Copyright (c) 2009 Princeton Satellite Systems, Inc. All rights reserved. ------------------------------------------------------------------------- Since version 8. -------------------------------------------------------------------------

Load the image

%---------------
q = ReadImage('CalibrationPattern.jpg');

Show the derivatives

%---------------------
[dX, dY] = GaussianDerivative( q, 0.05, 0.01 );
Imager(q,[],dX,1);
set(gcf,'name','|X Derivative|');
ColorMapGrayScale;
Imager(q,[],dY,1);
set(gcf,'name','|Y Derivative|');
ColorMapGrayScale;

Compute edge strength and direction. This takes the image derivative internally

%---------------------------------------------------------------------
sigma  = 0.05;
eps    = 0.01;
thresh = 0.01;

[eS, eO] = CannyEnhancer( q, sigma, eps, thresh );

Imager(q, [], eS, 1);
set(gcf,'name','Canny Enhancer : Strength');
Imager(q, [], 256*eO, 1);
set(gcf,'name','Canny Enhancer : Direction');

Thin the edges

%---------------
[iN, e0K] = NonMaxSuppression( eO, eS );

Imager(q, [], iN, 1);
set(gcf,'name','Non-Maximum Suppression');

This finds the curves

%----------------------
tauH      = 0.9*max(max(iN));
tauL      = 0.01*tauH;

HysteresisThreshold( iN, e0K, tauH, tauL )

%--------------------------------------

% $Id: cef2f83e48e75cef773be80bdd5d9f4023d3a329 $

ans =

  1×36 cell array

  Columns 1 through 4

    {2×27 double}    {2×2 double}    {2×30 double}    {2×2 double}

  Columns 5 through 8

    {2×29 double}    {2×2 double}    {2×2 double}    {2×3 double}

  Columns 9 through 12

    {2×2 double}    {2×2 double}    {2×2 double}    {2×2 double}

  Columns 13 through 16

    {2×27 double}    {2×2 double}    {2×30 double}    {2×2 double}

  Columns 17 through 20

    {2×2 double}    {2×2 double}    {2×2 double}    {2×2 double}

  Columns 21 through 24

    {2×2 double}    {2×2 double}    {2×2 double}    {2×2 double}

  Columns 25 through 28

    {2×27 double}    {2×2 double}    {2×30 double}    {2×2 double}

  Columns 29 through 32

    {2×2 double}    {2×2 double}    {2×2 double}    {2×3 double}

  Columns 33 through 36

    {2×2 double}    {2×2 double}    {2×2 double}    {2×2 double}

Published with MATLAB® R2022b