1 简介
本文采用区域生长算法对焊缝缺陷进行有效分割.该算法沿承传统区域生长算法的思想,主要依据边缘灰度突变的信息,在焊缝区域,先定位出所有可能的种子点并确定行方向上缺陷的边缘位置,再取对应处的像素灰度均值作为灰度阈值,最后从种子点开始并以不大于灰度阈值为判定准则进行生长.实验结果表明,该算法几乎能分割出焊缝中全部缺陷,并能使缺陷形状保留完整,这对后续缺陷的分类识别意义重大.
2 完整代码
clear all, close all, clc
f = imread('defective_weld.tif');
imshow(f), title('原始图象')
figure, [counts,x] = imhist(f); bar(x,counts), title('原始图象的直方图')
S = 255;
T = 65;
[g, NR, SI, TI] = regiongrow(f, S, T);
figure, imshow(SI), title('种子点图象')
figure, imshow(TI), title('阈值测试后的图象')
figure, imshow(g), title('8连通性分析后的图象')
bw = edge(g, 'canny');
figure, imshow(bw), title('边缘图象')
ff = f;
ff(bw) = 0;
figure, imshow(ff), title('叠加图象')
function [g, NR, SI, TI] = regiongrow(f, S, T)
%REGIONGROW Perform segmentation by region growing.
% [G, NR, SI, TI] = REGIONGROW(F, SR, T). S can be an array (the
% same size as F) with a 1 at the coordinates of every seed point
% and 0s elsewhere. S can also be a single seed value. Similarly,
% T can be an array (the same size as F) containing a threshold
% value for each pixel in F. T can also be a scalar, in which
% case it becomes a global threshold.
%
% On the output, G is the result of region growing, with each
% region labeled by a different integer, NR is the number of
% regions, SI is the final seed image used by the algorithm, and TI
% is the image consisting of the pixels in F that satisfied the
% threshold test.
% Copyright 2002-2004 R. C. Gonzalez, R. E. Woods, & S. L. Eddins
% Digital Image Processing Using MATLAB, Prentice-Hall, 2004
% $Revision: 1.4 $ $Date: 2003/10/26 22:35:37 $
f = double(f);
% If S is a scalar, obtain the seed image.
if numel(S) == 1
SI = f == S;
S1 = S;
else
% S is an array. Eliminate duplicate, connected seed locations
% to reduce the number of loop executions in the following
% sections of code.
SI = bwmorph(S, 'shrink', Inf);
J = find(SI);
S1 = f(J); % Array of seed values.
end
TI = false(size(f));
for K = 1:length(S1)
seedvalue = S1(K);
S = abs(f - seedvalue) <= T;
TI = TI | S;
end
% Use function imreconstruct with SI as the marker image to
% obtain the regions corresponding to each seed in S. Function
% bwlabel assigns a different integer to each connected region.
[g, NR] = bwlabel(imreconstruct(SI, TI));
3 仿真结果
4 参考文献
[1]孙太生等. "基于改进区域生长算法的焊缝图像分割." 现代焊接 2(2012):2.
部分理论引用网络文献，若有侵权联系博主删除。
5 MATLAB代码与数据下载地址
见博客主页
