function FM = fmeasure(Image, Measure, ROI)
%This function measures the relative degree of focus of 
%an image. It may be invoked as:
%
%   FM = fmeasure(IMAGE, METHOD, ROI)
%
%Where 
%   IMAGE,  is a grayscale image and FM is the computed
%           focus value.
%   METHOD, is the focus measure algorithm as a string.
%           see 'operators.txt' for a list of focus 
%           measure methods. 
%   ROI,    Image ROI as a rectangle [xo yo width heigth].
%           if an empty argument is passed, the whole
%           image is processed.
%
%  Said Pertuz
%  Jan/2016


if nargin>2 && ~isempty(ROI)
    Image = imcrop(Image, ROI);
end

WSize = 15; % Size of local window (only some operators)

switch upper(Measure)
    case 'ACMO' % Absolute Central Moment (Shirvaikar2004)
        if ~isinteger(Image), Image = im2uint8(Image);
        end
        FM = AcMomentum(Image);
                
    case 'BREN' % Brenner's (Santos97)
        [M, N] = size(Image);
        DH = zeros(M, N);
        DV = zeros(M, N);
        DV(1:M-2,:) = Image(3:end,:)-Image(1:end-2,:);
        DH(:,1:N-2) = Image(:,3:end)-Image(:,1:end-2);
        FM = max(DH, DV);        
        FM = FM.^2;
        FM = mean2(FM);
        
    case 'CONT' % Image contrast (Nanda2001)
        ImContrast = @(x) sum(abs(x(:)-x(5)));
        FM = nlfilter(Image, [3 3], ImContrast);
        FM = mean2(FM);
                        
    case 'CURV' % Image Curvature (Helmli2001)
        if ~isinteger(Image), Image = im2uint8(Image);
        end
        M1 = [-1 0 1;-1 0 1;-1 0 1];
        M2 = [1 0 1;1 0 1;1 0 1];
        P0 = imfilter(Image, M1, 'replicate', 'conv')/6;
        P1 = imfilter(Image, M1', 'replicate', 'conv')/6;
        P2 = 3*imfilter(Image, M2, 'replicate', 'conv')/10 ...
            -imfilter(Image, M2', 'replicate', 'conv')/5;
        P3 = -imfilter(Image, M2, 'replicate', 'conv')/5 ...
            +3*imfilter(Image, M2, 'replicate', 'conv')/10;
        FM = abs(P0) + abs(P1) + abs(P2) + abs(P3);
        FM = mean2(FM);
        
    case 'DCTE' % DCT energy ratio (Shen2006)
        FM = nlfilter(Image, [8 8], @DctRatio);
        FM = mean2(FM);
        
    case 'DCTR' % DCT reduced energy ratio (Lee2009)
        FM = nlfilter(Image, [8 8], @ReRatio);
        FM = mean2(FM);
        
    case 'GDER' % Gaussian derivative (Geusebroek2000)        
        N = floor(WSize/2);
        sig = N/2.5;
        [x,y] = meshgrid(-N:N, -N:N);
        G = exp(-(x.^2+y.^2)/(2*sig^2))/(2*pi*sig);
        Gx = -x.*G/(sig^2);
        Gx = Gx/sum(abs(Gx(:)));
        Gy = -y.*G/(sig^2);
        Gy = Gy/sum(abs(Gy(:)));
        Rx = imfilter(double(Image), Gx, 'conv', 'replicate');
        Ry = imfilter(double(Image), Gy, 'conv', 'replicate');
        FM = Rx.^2+Ry.^2;
        FM = mean2(FM);
        
    case 'GLVA' % Graylevel variance (Krotkov86)
        FM = std2(Image);
        
    case 'GLLV' %Graylevel local variance (Pech2000)        
        LVar = stdfilt(Image, ones(WSize,WSize)).^2;
        FM = std2(LVar)^2;
        
    case 'GLVN' % Normalized GLV (Santos97)
        FM = std2(Image)^2/mean2(Image);
        
    case 'GRAE' % Energy of gradient (Subbarao92a)
        Ix = Image;
        Iy = Image;
        Iy(1:end-1,:) = diff(Image, 1, 1);
        Ix(:,1:end-1) = diff(Image, 1, 2);
        FM = Ix.^2 + Iy.^2;
        FM = mean2(FM);
        
    case 'GRAT' % Thresholded gradient (Snatos97)
        Th = 0; %Threshold
        Ix = Image;
        Iy = Image;
        Iy(1:end-1,:) = diff(Image, 1, 1);
        Ix(:,1:end-1) = diff(Image, 1, 2);
        FM = max(abs(Ix), abs(Iy));
        FM(FM<Th)=0;
        FM = sum(FM(:))/sum(sum(FM~=0));
        
    case 'GRAS' % Squared gradient (Eskicioglu95)
        Ix = diff(Image, 1, 2);
        FM = Ix.^2;
        FM = mean2(FM);
        
    case 'HELM' %Helmli's mean method (Helmli2001)        
        MEANF = fspecial('average',[WSize WSize]);
        U = imfilter(Image, MEANF, 'replicate');
        R1 = U./Image;
        R1(Image==0)=1;
        index = (U>Image);
        FM = 1./R1;
        FM(index) = R1(index);
        FM = mean2(FM);
        
    case 'HISE' % Histogram entropy (Krotkov86)
        FM = entropy(Image);
        
    case 'HISR' % Histogram range (Firestone91)
        FM = max(Image(:))-min(Image(:));
        
           
    case 'LAPE' % Energy of laplacian (Subbarao92a)
        LAP = fspecial('laplacian');
        FM = imfilter(Image, LAP, 'replicate', 'conv');
        FM = mean2(FM.^2);
                
    case 'LAPM' % Modified Laplacian (Nayar89)
        M = [-1 2 -1];        
        Lx = imfilter(Image, M, 'replicate', 'conv');
        Ly = imfilter(Image, M', 'replicate', 'conv');
        FM = abs(Lx) + abs(Ly);
        FM = mean2(FM);
        
    case 'LAPV' % Variance of laplacian (Pech2000)
        LAP = fspecial('laplacian');
        ILAP = imfilter(Image, LAP, 'replicate', 'conv');
        FM = std2(ILAP)^2;
        
    case 'LAPD' % Diagonal laplacian (Thelen2009)
        M1 = [-1 2 -1];
        M2 = [0 0 -1;0 2 0;-1 0 0]/sqrt(2);
        M3 = [-1 0 0;0 2 0;0 0 -1]/sqrt(2);
        F1 = imfilter(Image, M1, 'replicate', 'conv');
        F2 = imfilter(Image, M2, 'replicate', 'conv');
        F3 = imfilter(Image, M3, 'replicate', 'conv');
        F4 = imfilter(Image, M1', 'replicate', 'conv');
        FM = abs(F1) + abs(F2) + abs(F3) + abs(F4);
        FM = mean2(FM);
        
    case 'SFIL' %Steerable filters (Minhas2009)
        % Angles = [0 45 90 135 180 225 270 315];
        N = floor(WSize/2);
        sig = N/2.5;
        [x,y] = meshgrid(-N:N, -N:N);
        G = exp(-(x.^2+y.^2)/(2*sig^2))/(2*pi*sig);
        Gx = -x.*G/(sig^2);Gx = Gx/sum(Gx(:));
        Gy = -y.*G/(sig^2);Gy = Gy/sum(Gy(:));
        R(:,:,1) = imfilter(double(Image), Gx, 'conv', 'replicate');
        R(:,:,2) = imfilter(double(Image), Gy, 'conv', 'replicate');
        R(:,:,3) = cosd(45)*R(:,:,1)+sind(45)*R(:,:,2);
        R(:,:,4) = cosd(135)*R(:,:,1)+sind(135)*R(:,:,2);
        R(:,:,5) = cosd(180)*R(:,:,1)+sind(180)*R(:,:,2);
        R(:,:,6) = cosd(225)*R(:,:,1)+sind(225)*R(:,:,2);
        R(:,:,7) = cosd(270)*R(:,:,1)+sind(270)*R(:,:,2);
        R(:,:,8) = cosd(315)*R(:,:,1)+sind(315)*R(:,:,2);
        FM = max(R,[],3);
        FM = mean2(FM);
        
    case 'SFRQ' % Spatial frequency (Eskicioglu95)
        Ix = Image;
        Iy = Image;
        Ix(:,1:end-1) = diff(Image, 1, 2);
        Iy(1:end-1,:) = diff(Image, 1, 1);
        FM = mean2(sqrt(double(Iy.^2+Ix.^2)));
        
    case 'TENG'% Tenengrad (Krotkov86)
        Sx = fspecial('sobel');
        Gx = imfilter(double(Image), Sx, 'replicate', 'conv');
        Gy = imfilter(double(Image), Sx', 'replicate', 'conv');
        FM = Gx.^2 + Gy.^2;
        FM = mean2(FM);
        
    case 'TENV' % Tenengrad variance (Pech2000)
        Sx = fspecial('sobel');
        Gx = imfilter(double(Image), Sx, 'replicate', 'conv');
        Gy = imfilter(double(Image), Sx', 'replicate', 'conv');
        G = Gx.^2 + Gy.^2;
        FM = std2(G)^2;
        
    case 'VOLA' % Vollath's correlation (Santos97)
        Image = double(Image);
        I1 = Image; I1(1:end-1,:) = Image(2:end,:);
        I2 = Image; I2(1:end-2,:) = Image(3:end,:);
        Image = Image.*(I1-I2);
        FM = mean2(Image);
        
    case 'WAVS' %Sum of Wavelet coeffs (Yang2003)
        [C,S] = wavedec2(Image, 1, 'db6');
        H = wrcoef2('h', C, S, 'db6', 1);   
        V = wrcoef2('v', C, S, 'db6', 1);   
        D = wrcoef2('d', C, S, 'db6', 1);   
        FM = abs(H) + abs(V) + abs(D);
        FM = mean2(FM);
        
    case 'WAVV' %Variance of  Wav...(Yang2003)
        [C,S] = wavedec2(Image, 1, 'db6');
        H = abs(wrcoef2('h', C, S, 'db6', 1));
        V = abs(wrcoef2('v', C, S, 'db6', 1));
        D = abs(wrcoef2('d', C, S, 'db6', 1));
        FM = std2(H)^2+std2(V)+std2(D);
        
    case 'WAVR'
        [C,S] = wavedec2(Image, 3, 'db6');
        H = abs(wrcoef2('h', C, S, 'db6', 1));   
        V = abs(wrcoef2('v', C, S, 'db6', 1));   
        D = abs(wrcoef2('d', C, S, 'db6', 1)); 
        A1 = abs(wrcoef2('a', C, S, 'db6', 1));
        A2 = abs(wrcoef2('a', C, S, 'db6', 2));
        A3 = abs(wrcoef2('a', C, S, 'db6', 3));
        A = A1 + A2 + A3;
        WH = H.^2 + V.^2 + D.^2;
        WH = mean2(WH);
        WL = mean2(A);
        FM = WH/WL;
    otherwise
        error('Unknown measure %s',upper(Measure))
end
 end
%************************************************************************
function fm = AcMomentum(Image)
[M, N] = size(Image);
Hist = imhist(Image)/(M*N);
Hist = abs((0:255)-mean2(Image))'.*Hist;
fm = sum(Hist);
end

%******************************************************************
function fm = DctRatio(M)
MT = dct2(M).^2;
fm = (sum(MT(:))-MT(1,1))/MT(1,1);
end

%************************************************************************
function fm = ReRatio(M)
M = dct2(M);
fm = (M(1,2)^2+M(1,3)^2+M(2,1)^2+M(2,2)^2+M(3,1)^2)/(M(1,1)^2);
end
%******************************************************************