图像压缩基于matlab GUI DCT图像无损压缩含Matlab源码 726期

Posted 2021-05-19 紫极神光

一、简介

基于matlab GUI图像无损压缩，提高图像压缩比；
DCT又称离散余弦变换，是一种块变换方式，只使用余弦函数来表达信号，与傅里叶变换紧密相关。常用于图像数据的压缩，通过将图像分成大小相等（一般为8*8）的块，利用DCT对其进行变换，得到更加简洁的数据。因为图像像素间存在较大的空间相关性，DCT可以大大减小这些相关性，使图像能量集中在左上角区域，从而利于数据压缩。变换后得到的数据称为DCT系数。这一过程是无损的。
二维DCT变换

这里来看看二维DCT变换的公式：

二、源代码

function varargout = ImageCompression1(varargin)
% IMAGECOMPRESSION1 MATLAB code for ImageCompression1.fig
%      IMAGECOMPRESSION1, by itself, creates a new IMAGECOMPRESSION1 or raises the existing
%      singleton*.
%
%      H = IMAGECOMPRESSION1 returns the handle to a new IMAGECOMPRESSION1 or the handle to
%      the existing singleton*.
%
%      IMAGECOMPRESSION1(\'CALLBACK\',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in IMAGECOMPRESSION1.M with the given input arguments.
%
%      IMAGECOMPRESSION1(\'Property\',\'Value\',...) creates a new IMAGECOMPRESSION1 or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before ImageCompression1_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to ImageCompression1_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 ImageCompression1

% Last Modified by GUIDE v2.5 15-Oct-2014 22:20:56

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct(\'gui_Name\',       mfilename, ...
                   \'gui_Singleton\',  gui_Singleton, ...
                   \'gui_OpeningFcn\', @ImageCompression1_OpeningFcn, ...
                   \'gui_OutputFcn\',  @ImageCompression1_OutputFcn, ...
                   \'gui_LayoutFcn\',  [] , ...
                   \'gui_Callback\',   []);
if nargin && ischar(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 ImageCompression1 is made visible.
function ImageCompression1_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 ImageCompression1 (see VARARGIN)

% Choose default command line output for ImageCompression1
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);
guidata(hObject, handles);
set(handles.axes1,\'visible\',\'off\')
set(handles.axes2,\'visible\',\'off\')
axis off
axis off
% UIWAIT makes ImageCompression1 wait for user response (see UIRESUME)
% uiwait(handles.figure1);


% --- Outputs from this function are returned to the command line.
function varargout = ImageCompression1_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;


% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global file_name;
%guidata(hObject,handles)
file_name=uigetfile({\'*.bmp;*.jpg;*.png;*.tiff;\';\'*.*\'},\'Select an Image File\');
fileinfo = dir(file_name);
SIZE = fileinfo.bytes;
Size = SIZE/1024;
set(handles.text7,\'string\',Size);
imshow(file_name,\'Parent\', handles.axes1)

% --- Executes on button press in pushbutton2.
function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global file_name;
if(~ischar(file_name))
   errordlg(\'Please select Images first\');
else
    I1 = imread(file_name);
% I1 = imread(\'chicken.jpg\');
I = I1(:,:,1);
I = im2double(I);
T = dctmtx(8);
B = blkproc(I,[8 8],\'P1*x*P2\',T,T\');
mask = [1   1   1   1   0   0   0   0
        1   1   1   0   0   0   0   0
        1   1   0   0   0   0   0   0
        1   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0];
B2 = blkproc(B,[8 8],\'P1.*x\',mask);
I2 = blkproc(B2,[8 8],\'P1*x*P2\',T\',T);

I = I1(:,:,2);
I = im2double(I);
T = dctmtx(8);
B = blkproc(I,[8 8],\'P1*x*P2\',T,T\');
mask = [1   1   1   1   0   0   0   0
        1   1   1   0   0   0   0   0
        1   1   0   0   0   0   0   0
        1   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0];
B2 = blkproc(B,[8 8],\'P1.*x\',mask);
I3 = blkproc(B2,[8 8],\'P1*x*P2\',T\',T);


I = I1(:,:,3);
I = im2double(I);
T = dctmtx(8);
B = blkproc(I,[8 8],\'P1*x*P2\',T,T\');
mask = [1   1   1   1   0   0   0   0
        1   1   1   0   0   0   0   0
        1   1   0   0   0   0   0   0
        1   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0
        0   0   0   0   0   0   0   0];
B2 = blkproc(B,[8 8],\'P1.*x\',mask);
I4 = blkproc(B2,[8 8],\'P1*x*P2\',T\',T);

三、运行结果

四、备注

版本：2014a
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