function thresholdtestdemo(imgname,wavename,level,deta)
%  thresholdtestdemo  小波變換在不同閾值下重構的測試演示程序
%  thresholdtestdemo(imgname,wavename,level,deta)
%  本程序作用:載入圖像信號,使用小波變換,比較顯示不同閾值下的重構圖像及相關信息
%  輸入: imgname   ----要裝載的圖像名稱
%        wavename  ----變換小波名稱
%        level     ----小波分解級數
%        deta      ----測試閾值增加值
%  缺省時:變換圖像為color256.png, 3級haar小波變換 deta=5

if nargin==0
    imgname='woman.jpg';
    wavename='haar';
    level=1;
    deta=90;
else
    if  nargin==1
        wavename='haar';
        level=3;
        deta=5;
    else
        if nargin==2
            level=3;
            deta=5;
        else
            if nargin==3
                deta=5;
            end
        end
    end
end

%  讀入的X中含有被裝載的圖像信號,map中含有被裝載的color
[X,map] = imread(imgname);

%檢測圖像格式
%輸入矩陣X為3維時為真彩色圖像,RGB三個分量需分別分解與重構
%輸入圖像為索引圖像時(map不為空),轉換為RGB真彩色圖像,再作分解與重構,因為索引圖每個像素的顏色值
%不是矩陣的數值,真正應該顯示的顏色為讀入的矩陣X上的值通過顏色表map變換得到的,如果直接用來作變換,即有可能會發生失真情況

if isempty(map)
    emp=1;
else
    X=ind2rgb(X,map)*255;
    emp=0;
end
if ndims(X)==3
    imgcolor=1;
    Xr=X(:,:,1);
    Xg=X(:,:,2);
    Xb=X(:,:,3);
else
    imgcolor=0;
end

info=imfinfo(imgname);
ss=round((info(1).FileSize)/1024);
sname=size(imgname);
orgname=imgname(1:sname(2)-4);
nfile=struct('name','');
X=double(X);
%畫出原始圖像
figure(1);
subplot(2,3,1);
imshow(uint8(X));colormap(map);        
title(strcat(wavename,'小波變換閾值測試(',mat2str(level),'級)'));
xlabel(strcat('原始圖像(Size: ',mat2str(ss),'KB)'));
axis square
%小波分解
if imgcolor
    [Cr,Sr]=wavedec2(Xr,level,wavename);
    [Cg,Sg]=wavedec2(Xg,level,wavename);
    [Cb,Sb]=wavedec2(Xb,level,wavename);
    C(1,:)=Cr;
    C(2,:)=Cg;
    C(3,:)=Cb;    
else
    [C,S]=wavedec2(X,level,wavename);
end

%在不同閾值下測試
T(1)=0;
for i=1:4
    %用0置換矩陣中絕對值小于閾值的數值
    if T(i)>0
        C(find(abs(C)<=T(i)))=0;
        %C=wthresh(C,'h',T(i));
    end
    
    %計算零的個數
    zeronum(i)=prod(size(find(C==0)));
    
    %重構不同閾值下圖像
    if imgcolor
        Cr=C(1,:);
        Cg=C(2,:);
        Cb=C(3,:);        
        Ar=waverec2(Cr,Sr,wavename);           
        Ag=waverec2(Cg,Sg,wavename);           
        Ab=waverec2(Cb,Sb,wavename);  
        A(:,:,1)=uint8(round(Ar));
        A(:,:,2)=uint8(round(Ag));
        A(:,:,3)=uint8(round(Ab));   
    else
        A=waverec2(C,S,wavename);   
        A=uint8(round(A));
    end
    
    %存貯新圖像,圖像名為原圖像名+小波名+閾值大小
    nfile(i).name=strcat(orgname,'_',wavename,'_',mat2str(T(i)),'.png');
    imwrite(A,nfile(i).name,'png');
    
    %獲取圖像大小信息
    info=imfinfo(nfile(i).name);
    if info(1).FileSize>1024
        sfile(i)=round((info(1).FileSize)/1024);
        sunit='KB';
    else
        sfile(i)=info(1).FileSize;
        sunit='B';
    end        

    %畫出重構圖像
    figure(1);
    subplot(2,3,i+1);
    imshow(uint8(A));                  
    title(strcat('閾值T=',int2str(T(i)),' (Size:',int2str(sfile(i)),sunit,')'));
    xlabel(strcat('系數含"0"數目=',int2str(zeronum(i))));
    axis square
    if i<3
        T(i+1)=T(i)+deta;
    else
        if i==3
            T(i+1)=T(i)+2*deta;
        end
    end;
end

%畫出不同閾值對應的文件大小及系數為零的關系圖
if and(or(min(zeronum)>1000,zeronum(1)==0),zeronum(4)/1000>sfile(4))
    zeronum=zeronum/1000;
    overth=1;
else
    overth=0;
end;
subplot(2,3,6);
plot(T,zeronum,'-rs','LineWidth',1,...
                'MarkerEdgeColor','k',...
                'MarkerFaceColor','g',...
                'MarkerSize',5);
hold on;
plot(T,sfile,'-bs','LineWidth',1,...
                'MarkerEdgeColor','k',...
                'MarkerFaceColor','y',...
                'MarkerSize',5);
xlabel('                         閾值T ');

%axis([0 20 min(sfile(1),zeronum(1)) max(sfile(4),zeronum(4))]);
meant=(zeronum(4)-sfile(4))/8;
if overth
    text(10,zeronum(4)+meant,'系數含"0"數目/1000');
else
    text(10,zeronum(4)+meant,'系數含"0"數目');
end    
text(15,sfile(4)+meant,strcat('文件大小(',sunit,')'));
axis square