b8a8ff2bc6
实现内容: - 网格划分:投影分析 + 自相关估周期 + 白顶帽去背景 + 质心提取 - 三种阈值分割:人工阈值、Otsu自动阈值、迭代阈值 - TV去噪(Chambolle投影算法) - 后处理:去小连通域 + 保留最大连通域 - 完整可视化:网格叠加、阈值对比、收敛曲线、分割结果 参考MATLAB代码:NewGridAndCV/demo_GriddingAndCV.m
305 lines
11 KiB
Matlab
305 lines
11 KiB
Matlab
%% Microarray Spot Finding Example
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% This example shows a simple method for locating spots on a microarray and
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% extracting the intensties of the spots. It can be downloaded from *MATLAB
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% Central*.
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% http://www.mathworks.com/matlabcentral
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%
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% Copyright 2004-2010 RBemis The MathWorks, Inc.
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%% Start with clean slate
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clear %empty workspace (no variables)
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close all %no figures
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clc %empty command window
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%% Read image file
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% MATLAB can read many standard image formats including TIFF, GIF and BMP
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% using the |imread| command. In addition, the *Image Procesing Toolbox*
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% provides support for working with specialized image file formats such as
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% DICOM. This microarray image was stored as a J-PEG file. The image is
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% much larger than the screen size, so |imshow| scales it down to fit and
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% let's you know with a warning message.
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% x = imread('MicroArraySlide.JPG');
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% imageSize = size(x)
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% screenSize = get(0,'ScreenSize')
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%
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% iptsetpref('ImshowBorder','tight')
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% imshow(x)
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% title('original image')
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%% Crop specified region
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% Next we use |imcrop| to extract a region of interest. You can repeat this
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% for all print-tip blocks for a full microarray study.
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% y = imcrop(x,[622 2467 220 227]);
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y=imread('test.tif');
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% y=imread('cDNA.png');
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% y=imread('test001.tif');
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% y = imread('C:\Users\Administrator\Desktop\中国生物医学工程学报(实验结果对比)\实验二\test001.tif');
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% y = imread('C:\Users\Administrator\Desktop\中国生物医学工程学报(实验结果对比)\实验三\test003.tif');
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f1 = figure('position',[40 46 285 280]);
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imshow(y)
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%% Display red & green layers
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% This image was stored in RGB format. We are only interested in the red
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% and green planes. To extract the red plane, simply index layer 1. For the
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% green plane, layer 2. Custom colormaps make visualization more intuitive.
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% Notice that spot shapes are not necessarily the same in both colors.
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f2 = figure('position',[265 163 647 327]);
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subplot(121)
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redMap = gray(256);
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redMap(:,[2 3]) = 0;
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subimage(y(:,:,1),redMap)
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axis off
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title('red (layer 1)')
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subplot(122)
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greenMap = gray(256);
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greenMap(:,[1 3]) = 0;
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subimage(y(:,:,2),greenMap)
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axis off
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title('green (layer 2)')
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%% Convert RGB image to grayscale for spot finding
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% Initially we care more about where the spots are located than their red
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% and green intensities. Converting from RGB color to grayscale allows us
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% to focus first on spot locations.
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z = rgb2gray(y);
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figure(f1)
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imshow(z)
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%% Create horizontal profile
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% We are looking for a regular grid of spots so we start by looking at the
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% mean intensity for each column of the image. This will help us identify
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% where the centres of the spots are and where the gaps between the spots
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% can be found.
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xProfile = mean(z);
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f2 = figure('position',[39 346 284 73]);
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plot(xProfile)
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title('horizontal profile')
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axis tight
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%% Estimate spot spacing by autocorrelation
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% Ideally the spots would be periodicaly spaced consistently printed, but
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% in practice they tend to have different sizes and intensities, so the
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% horizontal profile is irregular. We can use autocorrelation to enhance
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% the self similarity of the profile. The smooth result promotes peak
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% finding and estimation of spot spacing. The *Signal Processing Toolbox*
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% allows easy computation of the autocorrelation function using the |xcov|
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% command.
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ac = xcov(xProfile); %unbiased autocorrelation
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f3 = figure('position',[-3 427 569 94]);
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plot(ac)
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s1 = diff(ac([1 1:end])); %left slopes
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s2 = diff(ac([1:end end])); %right slopes
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maxima = find(s1>0 & s2<0); %peaks
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estPeriod = round(median(diff(maxima))) %nominal spacing
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hold on
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plot(maxima,ac(maxima),'r^')
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hold off
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title('autocorrelation of profile')
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axis tight
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%% Remove background morphologically
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% We can use the spacing estimate to help design a filter to remove the
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% background noise from the intensity profile. We do this with the
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% |imtophat| function from the *Image Processing Toolbox*. The |strel|
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% command creates a simple rectangular 1D window or line shaped structuring
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% element.
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seLine = strel('line',estPeriod,0);
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xProfile2 = imtophat(xProfile,seLine);
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f4 = figure('position',[40 443 285 76]);
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plot(xProfile2)
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title('enhanced horizontal profile')
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axis tight
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%% Segment peaks
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% Now that we have clean and anchored gaps between the peaks, we can number
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% each peak region with the |bwlabel| command. These regions were segmented
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% by thresholding with |im2bw|. The threshold value was automatically
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% determined by statistical properties of the data using |graythresh|. This
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% is a good example of image processing techniques are often useful for 1D
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% data analysis.
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level = graythresh(xProfile2/255)*255
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bw = im2bw(xProfile2/255,level/255);
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L = bwlabel(bw);
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f5 = figure('position',[40 540 285 70]);
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plot(L)
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axis tight
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title('labelled regions')
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%% Locate centers
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% We can extract the centroids of the peaks. These correspond to the
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% horizontal centres of the spots. This is a common blob analysis or
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% feature extraction task that can be done with |regionprops|.
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stats = regionprops(L);
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centroids = [stats.Centroid];
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xCenters = centroids(1:2:end)
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figure(f5)
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hold on
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plot(xCenters,1:max(L),'ro')
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hold off
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title('region centers')
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%% Determine divisions between spots
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% The midpoints between adjacent peaks provides grid point locations.
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gap = diff(xCenters)/2;
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first = xCenters(1)-gap(1);
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xGrid = round([first xCenters(1:end)+gap([1:end end])])
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figure(f2)
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for i=1:length(xGrid)
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line(xGrid(i)*[1 1],ylim,'color','m')
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end
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title('vertical separators')
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%% Transpose and repeat
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% We just did the analysis on the vertical grid. Now we want to do the same
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% for the horizontal spacing. To do this, we simply transpose the image and
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% repeat all the steps used above. This time without intermediate graphics
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% display commands in order to summarize the mathematical steps of this
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% algorithm.
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yProfile = mean(z'); %peak profile
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ac = xcov(yProfile); %cross correlation
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p1 = diff(ac([1 1:end]));
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p2 = diff(ac([1:end end]));
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maxima = find(p1>0 & p2<0); %peak locations
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estPeriod = round(median(diff(maxima))) %spacing estimate
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seLine = strel('line',estPeriod,0);
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yProfile2 = imtophat(yProfile,seLine); %background removed
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level = graythresh(yProfile2/255); %automatic threshold level
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bw = im2bw(yProfile2/255,level); %binarized peak regions
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L = bwlabel(bw); %labeled regions
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stats = regionprops(L);
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centroids = [stats.Centroid]; %centroids
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yCenters = centroids(1:2:end) %Y parts only
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gap = diff(yCenters)/2; %inner region half widths
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first = yCenters(1)-gap(1);
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% list defining vertical boundaries between spot regions
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yGrid = round([first yCenters(1:end)+gap([1:end end])])
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%% Put bounding boxes around each spot
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% We have now found the rectangular grid. Using pairs of neighboring grid
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% points we can form bounding box regions to address each spot
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% individually. The position and size coordinates of each bounding box were
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% tabulated for convenience into a 4-column matrix called |ROI|, which
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% stands for regions of interest.
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% figure(f1)
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figure()
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imshow(z)
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line(xGrid'*[1 1],yGrid([1 end]),'color','b')
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line(xGrid([1 end]),yGrid'*[1 1],'color','b')
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[X,Y] = meshgrid(xGrid(1:end-1),yGrid(1:end-1)); %xGrid和yGrid中存储了分格子的数据
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[dX,dY] = meshgrid(diff(xGrid),diff(yGrid));
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ROI = [X(:) Y(:) dX(:) dY(:)];
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% first few rows of ROI table
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ROI(1:5,:)
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%%
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%
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I=y;
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% location_row=xGrid;
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% location_col=yGrid;
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location_row=yGrid;
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location_col=xGrid;
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for ii = 1:length(location_row)-1
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for jj = 1: length(location_col)-1
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subimage = I([location_row(ii):location_row(ii+1)],[location_col(jj):location_col(jj+1)],:);%从I中取出每个grid的数据
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subimage_double = double(subimage);
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%%%% 转换数据到[0,1]之间,然后转换到[0,255]之间
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sumimage_01 = (subimage_double-min(subimage_double(:)))./max(subimage_double(:))-min(subimage_double(:)); %将每个grid的数据转换到[0,1]之间
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% subimage_norm = uint8(255*sumimage_01);%原文
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subimage_norm = uint8(255*sumimage_01);
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%%%% TV去噪
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subimage_norm(:,:,1)= tvdenoise(double(subimage_norm(:,:,1)),0.01);
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subimage_norm(:,:,2)= tvdenoise(double(subimage_norm(:,:,2)),0.01);
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subimage_norm(:,:,3)= tvdenoise(double(subimage_norm(:,:,3)),0.01);
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I_norm([location_row(ii):location_row(ii+1)],[location_col(jj):location_col(jj+1)],:)=subimage_norm;%每个grid的数据
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%%
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%用CV方法进行分割
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if mean(mean(subimage_norm(:,:,1)))<5 %%如果均值小于5,增强5图像
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subimage_norm=5*subimage_norm;
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else if mean(mean(subimage_norm(:,:,1)))<30 %%如果均值小于30,增强1.5图像
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subimage_norm=1.5*subimage_norm;
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end
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end
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iter=500;
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dt=0.1;
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u0=cvseg(subimage_norm,iter,dt); %C-V水平集分割
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% u1=im2bw(u0);
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%非数字的点设为默认值0
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[m_u0,n_u0]=size(u0);
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for i=1:m_u0
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for j=1:n_u0
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if(isnan(u0(i,j)))
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u0(i,j)=0;
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end
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end
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end
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% subimage_bw=u0;
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%若最后一列的第一个点或最后一个点为白色,则取反
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u1=u0;
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if(u1(end,1)==1 || u1(end,end))
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u2=1-u1;
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else
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u2=u1;
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end
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subimage_bw=u2;
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% subimage_bw为获得的二值图像,即为传递到下一步的图像
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%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%分割结束%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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I_bw([location_row(ii):location_row(ii+1)],[location_col(jj):location_col(jj+1)],:)=subimage_bw;%每个grid的数据;
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end
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end
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figure,imshow(I_bw)
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%显示与原图大学相等的二值图像
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all_bw=zeros(size(y(:,:,1)));
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all_bw(1:location_row(end),1:location_col(end))=I_bw;
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figure(),imshow(all_bw)
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%%
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I_bw1=all_bw;
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I_bw_01=choice(I_bw1,100); %%剔除面积大于100的目标(100仅为本次设定的阈值),这里最好用直方图的方法确定阈值,则更具普适性
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figure(),imshow(I_bw_01);
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%%
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num_sub_I_bw_02=0;
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for ii = 1:length(location_row)-1
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for jj = 1: length(location_col)-1
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sub_I_bw_01 = I_bw_01([location_row(ii):location_row(ii+1)],[location_col(jj):location_col(jj+1)],:);
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sub_I_bw_02=choosemaxobj(sub_I_bw_01,8);%剔除面积小于20的点
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[m,n]=size(sub_I_bw_02);
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for i=1:m
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for j=1:n
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if(sub_I_bw_02(1,j)==1 || sub_I_bw_02(i,1)==1|| sub_I_bw_02(m,j)==1 || sub_I_bw_02(i,n)==1)
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num_sub_I_bw_02=num_sub_I_bw_02+1;
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end
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end
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end
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if(num_sub_I_bw_02>10)
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sub_I_bw_02=zeros(size(sub_I_bw_02));
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end
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num_sub_I_bw_02=0;%每次计算完毕清零
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I_bw_Last_01([location_row(ii):location_row(ii+1)],[location_col(jj):location_col(jj+1)],:)=sub_I_bw_02;%每个grid的数据;
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end
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end
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all_bw_01=zeros(size(y(:,:,1)));
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all_bw_01(1:location_row(end),1:location_col(end))=I_bw_Last_01;
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figure(),imshow(all_bw_01);
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