phasecong.rar_illumination_matlab 边缘_matlab 边缘检测_phasecong_相位一致检

% PHASECONG - Computes phase congruency on an image. % % Usage: [pc or ft] = phasecong(im) % % This function calculates the PC_2 measure of phase congruency. % For maximum speed the input image should be square and have a % size that is a power of 2, but the code will operate on images % of arbitrary size. % % % Returned values: % pc - Phase congruency image (values between 0 and 1) % or - Orientation image. Provides orientation in which % local energy is a maximum in in degrees (0-180), % angles positive anti-clockwise. % ft - A complex valued image giving the weighted mean % phase angle at every point in the image for the % orientation having maximum energy. Use the % function DISPFEAT to display this data. % % Parameters: % im - A greyscale image to be processed. % % You can also specify numerous optional parameters. See the code to find % out what they are. The convolutions are done via the FFT. Many of the % parameters relate to the specification of the filters in the frequency % plane. Default values for parameters are set within the file rather than % being required as arguments because they rarely need to be changed - nor % are they very critical. However, you may want to experiment with % specifying/editing the values of `nscales' and `noiseCompFactor'. % % Note this phase congruency code is very computationally expensive and uses % *lots* of memory. % % % Example MATLAB session: % % >> im = imread('picci.tif'); % >> image(im); % Display the image % >> [pc or ft] = phasecong(im); % >> imagesc(pc), colormap(gray); % Display the phase congruency image % % % To convert the phase congruency image to an edge map (with my usual parameters): % % >> nm = nonmaxsup(pc, or, 1.5); % Non-maxima suppression. % The parameter 1.5 can result in edges more than 1 pixel wide but helps % in picking up `broad' maxima. % >> edgim = hysthresh(nm, 0.4, 0.2); % Hysteresis thresholding. % >> edgeim = bwmorph(edgim,'skel',Inf); % Skeletonize the edgemap to fix % % the non-maximal suppression. % >> imagesc(edgeim), colormap(gray); % % % To display the different feature types present in your image use: % % >> dispfeat(ft,edgim); % % With a small amount of editing the code can be modified to calculate % a dimensionless measure of local symmetry in the image. The basis % of this is that one looks for points in the image where the local % phase is 90 or 270 degrees (the symmetric points in the cycle). % Editing instructions are within the code. % % Notes on filter settings to obtain even coverage of the spectrum % dthetaOnSigma 1.5 % sigmaOnf .85 mult 1.3 % sigmaOnf .75 mult 1.6 (bandwidth ~1 octave) % sigmaOnf .65 mult 2.1 % sigmaOnf .55 mult 3 (bandwidth ~2 octaves) % % References: % % Peter Kovesi, "Image Features From Phase Congruency". Videre: A % Journal of Computer Vision Research. MIT Press. Volume 1, Number 3, % Summer 1999 http://mitpress.mit.edu/e-journals/Videre/001/v13.html % Copyright (c) 1996-2005 Peter Kovesi % School of Computer Science & Software Engineering % The University of Western Australia % http://www.csse.uwa.edu.au/ % % Permission is hereby granted, free of charge, to any person obtaining a copy % of this software and associated documentation files (the "Software"), to deal % in the Software without restriction, subject to the following conditions: % % The above copyright notice and this permission notice shall be included in % all copies or substantial portions of the Software. % % The Software is provided "as is", without warranty of any kind. % Original Version written April 1996 % Noise compensation corrected. August 1998 % Noise compensation corrected. October 1998 - Again!!! % Modified to operate on non-square images of arbitrary size. September 1999 % Modified to return feature type image. May 2001 function[phaseCongruency,orientation, featType]=phasecong(im, nscale, norient, ... minWaveLength, mult, ... sigmaOnf, dThetaOnSigma, ... k, cutOff) sze = size(im); if nargin < 2 nscale = 3; % Number of wavelet scales. end if nargin < 3 norient = 6; % Number of filter orientations. end if nargin < 4 minWaveLength = 3; % Wavelength of smallest scale filter. end if nargin < 5 mult = 2; % Scaling factor between successive filters. end if nargin < 6 sigmaOnf = 0.55; % Ratio of the standard deviation of the % Gaussian describing the log Gabor filter's transfer function % in the frequency domain to the filter center frequency. end if nargin < 7 dThetaOnSigma = 1.7; % Ratio of angular interval between filter orientations % and the standard deviation of the angular Gaussian % function used to construct filters in the % freq. plane. end if nargin < 8 k = 3.0; % No of standard deviations of the noise energy beyond the % mean at which we set the noise threshold point. % standard deviation to its maximum effect % on Energy. end if nargin < 9 cutOff = 0.4; % The fractional measure of frequency spread % below which phase congruency values get penalized. end g = 10; % Controls the sharpness of the transition in the sigmoid % function used to weight phase congruency for frequency % spread. epsilon = .0001; % Used to prevent division by zero. thetaSigma = pi/norient/dThetaOnSigma; % Calculate the standard deviation of the % angular Gaussian function used to % construct filters in the freq. plane. imagefft = fft2(im); % Fourier transform of image sze = size(imagefft); rows = sze(1); cols = sze(2); zero = zeros(sze); totalEnergy = zero; % Matrix for accumulating weighted phase % congruency values (energy). totalSumAn = zero; % Matrix for accumulating filter response % amplitude values. orientation = zero; % Matrix storing orientation with greatest % energy for each pixel. estMeanE2n = []; % Pre-compute some stuff to speed up filter construction x = ones(rows,1) * (-cols/2 : (cols/2 - 1))/(cols/2); y = (-rows/2 : (rows/2 - 1))' * ones(1,cols)/(rows/2); radius = sqrt(x.^2 + y.^2); % Matrix values contain *normalised* radius from centre. radius(round(rows/2+1),round(cols/2+1)) = 1; % Get rid of the 0 radius value in the middle % so that taking the log of the radius will % not cause trouble. theta = atan2(-y,x); % Matrix values contain polar angle. % (note -ve y is used to give +ve % anti-clockwise angles) sintheta = sin(theta); costheta = cos(theta); clear x; clear y; clear theta; % save a little memory % The main loop... for o = 1:norient, % For each orientation. disp(['Processing orientation ' num2str(o)]); angl = (o-1)*pi/norient; % Calculate filter angle. wavelength = minWaveLength; % Initialize filter wavelength. sumE_ThisOrient = zero; % Initialize accumulator matrices. sumO_ThisOrient = zero; sumAn_ThisOrient = zero; Energy_ThisOrient = zero; EOArray = []; % Array of complex convolution ima