基于L0约束实现图像平滑处理附matlab代码

% Distribution code Version 1.0 -- 09/23/2011 by Jiaya Jia Copyright 2011, The Chinese University of Hong Kong. % % The Code is created based on the method described in the following paper % [1] "Image Smoothing via L0 Gradient Minimization", Li Xu, Cewu Lu, Yi Xu, Jiaya Jia, ACM Transactions on Graphics, % (SIGGRAPH Asia 2011), 2011. % % The code and the algorithm are for non-comercial use only. function S = L0Smoothing(Im, lambda, kappa) %L0Smooth - Image Smoothing via L0 Gradient Minimization % S = L0Smooth(Im, lambda, kappa) performs L0 graidient smoothing of input % image Im, with smoothness weight lambda and rate kappa. % % Paras: % @Im : Input UINT8 image, both grayscale and color images are acceptable. % @lambda: Smoothing parameter controlling the degree of smooth. (See [1]) % Typically it is within the range [1e-3, 1e-1], 2e-2 by default. % @kappa : Parameter that controls the rate. (See [1]) % Small kappa results in more iteratioins and with sharper edges. % We select kappa in (1, 2]. % kappa = 2 is suggested for natural images. % % Example % ========== % Im = imread('pflower.jpg'); % S = L0Smooth(Im); % Default Parameters (lambda = 2e-2, kappa = 2) % figure, imshow(Im), figure, imshow(S); if ~exist('kappa','var') kappa = 2.0; end if ~exist('lambda','var') lambda = 2e-2; end S = im2double(Im); betamax = 1e5; fx = [1, -1]; fy = [1; -1]; [N,M,D] = size(Im); sizeI2D = [N,M]; otfFx = psf2otf(fx,sizeI2D); otfFy = psf2otf(fy,sizeI2D); Normin1 = fft2(S); Denormin2 = abs(otfFx).^2 + abs(otfFy ).^2; if D>1 Denormin2 = repmat(Denormin2,[1,1,D]); end beta = 2*lambda; while beta < betamax Denormin = 1 + beta*Denormin2; % h-v subproblem h = [diff(S,1,2), S(:,1,:) - S(:,end,:)]; v = [diff(S,1,1); S(1,:,:) - S(end,:,:)]; if D==1 t = (h.^2+v.^2)<lambda/beta; else t = sum((h.^2+v.^2),3)<lambda/beta; t = repmat(t,[1,1,D]); end h(t)=0; v(t)=0; % S subproblem Normin2 = [h(:,end,:) - h(:, 1,:), -diff(h,1,2)]; Normin2 = Normin2 + [v(end,:,:) - v(1, :,:); -diff(v,1,1)]; FS = (Normin1 + beta*fft2(Normin2))./Denormin; S = real(ifft2(FS)); beta = beta*kappa; fprintf('.'); end fprintf('\n'); end