1 内容介绍
为了改进噪声鲁棒性和定位准确性,利用各向异性高斯方向导数滤波器,提出多方向角点检测算法.该算法利用一组各向异性高斯方向导数滤波器对输入图像进行卷积处理得到各个方向的滤波器响应.对于每个像素点,利用它与周围邻近像素点的滤波器响应的相关信息构造局部自相关矩阵,然后根据自相关矩阵归一化特征值及像素点处各方向滤波器响应,作阈值处理和非极大值抑制处理判定像素点是否为角点.实验结果表明,在无噪声和噪声的条件下,提出的检测方法与各向同性高斯核函数的Harris算法相比,配准角点数均提高6.0%左右,具有更好的检测性能.
2 部分代码
function varargout = ch3(varargin)
% CH3 M-file for ch3.fig
% CH3, by itself, creates a new CH3 or raises the existing
% singleton*.
%
% H = CH3 returns the handle to a new CH3 or the handle to
% the existing singleton*.
%
% CH3('CALLBACK',hObject,eventData,handles,...) calls the local
% function named CALLBACK in CH3.M with the given input arguments.
%
% CH3('Property','Value',...) creates a new CH3 or raises the
% existing singleton*. Starting from the left, property value pairs are
% applied to the GUI before ch3_OpeningFunction gets called. An
% unrecognized property name or invalid value makes property application
% stop. All inputs are passed to ch3_OpeningFcn via varargin.
%
% *See GUI Options on GUIDE's Tools menu. Choose "GUI allows only one
% instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES
% Edit the above text to modify the response to help ch3
% Last Modified by GUIDE v2.5 10-Oct- 08:46:09
% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name', mfilename, ...
'gui_Singleton', gui_Singleton, ...
'gui_OpeningFcn', @ch3_OpeningFcn, ...
'gui_OutputFcn', @ch3_OutputFcn, ...
'gui_LayoutFcn', [] , ...
'gui_Callback', []);
if nargin & isstr(varargin{1})
gui_State.gui_Callback = str2func(varargin{1});
end
if nargout
[varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT
% --- Executes just before ch3 is made visible.
function ch3_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject handle to figure
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% varargin command line arguments to ch3 (see VARARGIN)
% Choose default command line output for ch3
handles.output = hObject;
% Update handles structure
guidata(hObject, handles);
% UIWAIT makes ch3 wait for user response (see UIRESUME)
% uiwait(handles.figure1);
% --- Outputs from this function are returned to the command line.
function varargout = ch3_OutputFcn(hObject, eventdata, handles)
% varargout cell array for returning output args (see VARARGOUT);
% hObject handle to figure
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Get default command line output from handles structure
varargout{1} = handles.output;
% --------------------------------------------------------------------
function Files_Callback(hObject, eventdata, handles)
% hObject handle to Files (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% --------------------------------------------------------------------
function Open_Callback(hObject, eventdata, handles)
% hObject handle to Open (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
[filename,pathname]=uigetfile({'*.bmp'},'选择图片');
global str;
if isequal(filename,0)
disp('Users Selected Canceled');
else
str=[pathname filename];
handles.str=str;
guidata(hObject,handles);
im = imread(str);
axes(handles.OImageDisplay);
imshow(im);
end;
% --------------------------------------------------------------------
function det_Callback(hObject, eventdata, handles)
% hObject handle to det (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% --------------------------------------------------------------------
function Hardet_Callback(hObject, eventdata, handles)
% hObject handle to Untitled_2 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
%清屏，所以变量置零
%记录检测的角点数
count=0;
for i1=2:height-1;
for j1=2:width-1
% 在3*3窗口范围内寻找局部最大值点作为检测出的角点
a=[R(i1-1,j1-1) R(i1-1,j1) R(i1-1,j1+1) R(i1,j1-1) R(i1,j1+1) R(i1+1,j1-1) R(i1+1,j1) R(i1+1,j1+1)];
if R(i1,j1)>0.01*Rmax && R(i1,j1)>max(a)
Result(i1,j1)=1;
count=count+1;
end
end
end
% 纪录角点位置
[posr,posc]=find(Result==1);
% 输出角点个数
%fprintf('检测到的角点数count=%d\n',count);
set(handles.text3,'String',num2str(count));
axes(handles.DetImage);
imshow(image);
hold on;
%角点处画+
plot(posc,posr,'r+');
3 运行结果
4 参考文献
[1]周文天 李军民 唐慧娟 李科. 基于高斯差分滤波和形态学滤波的Harris角点检测算法[J]. 西华大学学报：自然科学版, , 33(6):4.
[2]章为川, 张智, 赵强,等. 基于各向异性高斯方向导数滤波器的角点检测[J]. 西安工程大学学报, , 28(4):5.
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