发布时间:2022-09-21 21:00
针对眼底视网膜图像对比度低,受病变区域边界干扰,很难正确提取血管细节的问题提出了一种基于Frangi滤波器的视网膜血管分割的方法,仿真结果表明上述方法对细小血管的提取表现出良好的效果,具备很强的实用价值.
function I=imgaussian(I,sigma,siz)
% IMGAUSSIAN filters an 1D, 2D color/greyscale or 3D image with an
% Gaussian filter. This function uses for filtering IMFILTER or if
% compiled the fast mex code imgaussian.c . Instead of using a
% multidimensional gaussian kernel, it uses the fact that a Gaussian
% filter can be separated in 1D gaussian kernels.
%
% J=IMGAUSSIAN(I,SIGMA,SIZE)
%
% inputs,
% I: The 1D, 2D greyscale/color, or 3D input image with
% data type Single or Double
% SIGMA: The sigma used for the Gaussian kernel
% SIZE: Kernel size (single value) (default: sigma*6)
%
% outputs,
% J: The gaussian filtered image
%
% note, compile the code with: mex imgaussian.c -v
%
% example,
% I = im2double(imread('peppers.png'));
% figure, imshow(imgaussian(I,10));
%
% Function is written by D.Kroon University of Twente (September 2009)
if(~exist('siz','var')), siz=sigma*6; end
if(sigma>0)
% Make 1D Gaussian kernel
x=-ceil(siz/2):ceil(siz/2);
H = exp(-(x.^2/(2*sigma^2)));
H = H/sum(H(:));
% Filter each dimension with the 1D Gaussian kernels\
if(ndims(I)==1)
I=imfilter(I,H, 'same' ,'replicate');
elseif(ndims(I)==2)
Hx=reshape(H,[length(H) 1]);
Hy=reshape(H,[1 length(H)]);
I=imfilter(imfilter(I,Hx, 'same' ,'replicate'),Hy, 'same' ,'replicate');
elseif(ndims(I)==3)
if(size(I,3)<4) % Detect if 3D or color image
Hx=reshape(H,[length(H) 1]);
Hy=reshape(H,[1 length(H)]);
for k=1:size(I,3)
I(:,:,k)=imfilter(imfilter(I(:,:,k),Hx, 'same' ,'replicate'),Hy, 'same' ,'replicate');
end
else
Hx=reshape(H,[length(H) 1 1]);
Hy=reshape(H,[1 length(H) 1]);
Hz=reshape(H,[1 1 length(H)]);
I=imfilter(imfilter(imfilter(I,Hx, 'same' ,'replicate'),Hy, 'same' ,'replicate'),Hz, 'same' ,'replicate');
end
else
error('imgaussian:input','unsupported input dimension');
end
end
[1]袁盼, 陈以. 基于多尺度Frangi滤波器的视网膜血管分割[J]. 现代信息科技, 2020.
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