Matlab计算水下彩色图像质量指标UIQM的代码

以下是计算水下彩色图像质量指标UIQM的Matlab代码：

function [uiqm] = UIQM(img)

% RGB to YCbCr conversion
if size(img,3)==3
    img = rgb2ycbcr(img);
end

% Parameters initialization
mu = [0.01 0.03];
mask = fspecial('gaussian', 7, 7/6);
mask = mask / sum(mask(:));
K = 0.01;

% Mean and variance calculation
Y = img(:,:,1)/255;
Cb = img(:,:,2)/255;
Cr = img(:,:,3)/255;
muY = filter2(mask, Y, 'same');
muCb = filter2(mask, Cb, 'same');
muCr = filter2(mask, Cr, 'same');
Y = Y - muY;
Cb = Cb - muCb;
Cr = Cr - muCr;
sigmaY = sqrt(abs(filter2(mask, Y.^2, 'same')));
sigmaCb = sqrt(abs(filter2(mask, Cb.^2, 'same')));
sigmaCr = sqrt(abs(filter2(mask, Cr.^2, 'same')));

% Colorfulness calculation
RG = img(:,:,1) - img(:,:,2);
YB = (img(:,:,1) + img(:,:,2))/2 - img(:,:,3);
stdRG = sqrt(abs(filter2(mask, RG.^2, 'same')));
stdYB = sqrt(abs(filter2(mask, YB.^2, 'same')));
meanRG = filter2(mask, RG, 'same');
meanYB = filter2(mask, YB, 'same');
colorfulness = sqrt(stdRG.^2 + stdYB.^2 + (K*meanRG).^2 + (K*meanYB).^2);

% Contrast calculation
contrast = (sigmaY + sigmaCb + sigmaCr) / 3;

% Structure calculation
L = YCbCr2Luminance(img);
muL = filter2(mask, L, 'same');
L = L - muL;
sigmaL = sqrt(abs(filter2(mask, L.^2, 'same')));
structure = sigmaL;

% Sharpness calculation
S = sharpness(img);
sharpness = filter2(mask, S, 'same');

% Overall quality calculation
uiqm = (mu(1)*colorfulness) - (mu(2)*contrast) + ((1-mu(1)-mu(2))*structure.*sharpness);

end

function [L] = YCbCr2Luminance(img)

% YCbCr to Luminance conversion
Y = img(:,:,1);
Cb = img(:,:,2);
Cr = img(:,:,3);
L = 0.299*Y + 0.587*Cb + 0.114*Cr;

end

function [S] = sharpness(img)

% Sobel operator for edge detection
SobelX = [-1 0 1; -2 0 2; -1 0 1];
SobelY = SobelX';

% Image gradients calculation
grayImg = rgb2gray(img);
Ix = imfilter(double(grayImg), SobelX, 'replicate');
Iy = imfilter(double(grayImg), SobelY, 'replicate');
G = sqrt(Ix.^2 + Iy.^2);

% Sharpness calculation
S = mean2(G);

end

其中，`img`为输入的水下彩色图像，`uiqm`为计算得到的UIQM指标。注意，该代码需要调用Matlab Image Processing Toolbox中的函数，如`rgb2ycbcr`和`imfilter`，请确保已经安装并加载该工具箱。