MATLAB图像处理 - 查找图像的边缘和区域

Question

作为序言:这是我的第一个问题 - 我尽力使其尽可能明确,但如果不符合要求的标准我会道歉.

作为夏季项目的一部分,我正在拍摄一张在冰晶中生长的内部融化图像的延时图像.对于这些图像中的每一个,我想测量所形成的图形的周长和面积.以下链接是我的一张图片的示例:

我正在尝试使用的方法如下:

1. 加载图像,裁剪并转换为灰度
2. 减少噪音的过程
3. 找到边缘/周长
4. 尝试连接边缘
5. 用白色填充周长
6. 使用regionprops测量面积和周长

这是我正在使用的代码:

clear; close all;

% load image and convert to grayscale
tyrgb = imread('TyndallTest.jpg');
ty    = rgb2gray(tyrgb);
figure; imshow(ty)

% apply a weiner filter to remove noise.
% N is a measure of the window size for detecting coherent features
N=20;
tywf  = wiener2(ty,[N,N]);
tywf = tywf(N:end-N,N:end-N);

% rescale the image adaptively to enhance contrast without enhancing noise
tywfb = adapthisteq(tywf);

% apply a canny edge detection
tyedb = edge(tywfb,'canny');

%join edges
diskEnt1 = strel('disk',8); % radius of 4
tyjoin1 = imclose(tyedb,diskEnt1);
figure; imshow(tyjoin1)

正是在这个阶段我才挣扎.无论我如何使用形态结构元素,边缘都不会完全连接.也许有更好的方法来完成边缘？Linked是此代码输出的图的示例:

我试图加入边缘的原因是我可以用白色像素填充周边,然后使用regionprops输出区域.我已经尝试使用imfill命令,但似乎无法填充轮廓,因为在周边内有大量的暗区域要填充.

在这种情况下,是否有更好的方法可以获得其中一个融化数字的区域更合适？

作为背景研究:我可以使用下面的代码使这个方法适用于由白色背景上的黑色圆圈组成的简单图像.但是我不知道如何编辑它来处理边缘定义不太清晰的更复杂的图像.

clear all
close all
clc

%% Read in RGB image from directory
RGB1 = imread('1.jpg')   ;

%% Convert RPG image to grayscale image
I1 = rgb2gray(RGB1)       ;

%% Transform Image
%CROP
IC1 = imcrop(I1,[74 43 278 285]);

%BINARY IMAGE 
BW1 = im2bw(IC1); %Convert to binary image so the boundary can be traced

%FIND PERIMETER
BWP1 = bwperim(BW1); 
%Traces perimeters of objects & colours them white (1). 
%Sets all other pixels to black (0)
%Doing the same job as an edge detection algorithm?

%FILL PERIMETER WITH WHITE IN ORDER TO MEASURE AREA AND PERIMETER
BWF1 = imfill(BWP1); %This opens  figure and allows you to select the areas to fill with white.

%MEASURE PERIMETER
D1 = regionprops(BWF1, 'area', 'perimeter'); 
%Returns an array containing the properties area and perimeter. 
%D1(1) returns the perimeter of the box and an area value identical to that
%perimeter? The box must be  bounded by a perimeter.
%D1(2) returns the perimeter and area of the section filled in BWF1

%% Display Area and Perimeter data
D1(2)

Answer 1

您可能需要考虑活动轮廓。这将为您提供对象的连续边界，而不是零散的边缘。

以下是链接

一本书：

http://www.amazon.co.uk/Active-Contours-Application-Techniques-Statistics/dp/1447115570/ref=sr_1_fkmr2_1?ie=UTF8&qid=1377248739&sr=8-1-fkmr2&keywords=Active+shape+models+Andrew+布莱克%2C+迈克尔+艾萨德

演示： http: //users.ecs.soton.ac.uk/msn/book/new_demo/Snakes/

以及文件交换上的一些 Matlab 代码： http://www.mathworks.co.uk/matlabcentral/fileexchange/28149-snake-active-contour

以及如何实现它的描述的链接：http ://www.cb.uu.se/~cris/blog/index.php/archives/217

使用文件交换上的实现，您可以获得如下结果：

%% Load the image
% You could use the segmented image obtained previously
% and then apply the snake on that (although I use the original image).
% This will probably make the snake work better and the edges
% in your image is not that well defined.
% Make sure the original and the segmented image 
% have the same size. They don't at the moment
I = imread('33kew0g.jpg');

% Convert the image to double data type
I = im2double(I); 
% Show the image and select some points with the mouse (at least 4)
% figure, imshow(I); [y,x] = getpts; 
% I have pre-selected the coordinates already
x = [  525.8445   473.3837   413.4284   318.9989   212.5783   140.6320    62.6902    32.7125    55.1957    98.6633   164.6141   217.0749   317.5000   428.4172   494.3680   527.3434   561.8177   545.3300];
y = [  435.9251  510.8691  570.8244  561.8311  570.8244  554.3367  476.3949  390.9586  311.5179  190.1085  113.6655   91.1823   98.6767  106.1711  142.1443  218.5872  296.5291      375.9698];

% Make an array with the selected coordinates
P=[x(:) y(:)];
%% Start Snake Process
% You probably have to fiddle with the parameters
% a bit more that I have
Options=struct;
Options.Verbose=true;
Options.Iterations=1000;
Options.Delta = 0.02;
Options.Alpha = 0.5;
Options.Beta = 0.2;
figure(1);
[O,J]=Snake2D(I,P,Options);