第5章 圖像的變化(本科生)

第5章

圖像的變化15.1.1-1.顏色反相真彩色顏色反相非真彩色顏色反相25.1.1-1.顏色反相顏色反相是指正相變負(fù)相，或負(fù)相變正相g=Max-f對(duì)于二值圖像Max取值1對(duì)于256色的圖像Max取值255。真彩色圖像的3個(gè)顏色分量都需進(jìn)行這樣的運(yùn)算非真彩色圖像只需修改調(diào)色板單元的數(shù)值演示程序：色調(diào)變化/顏色反相第五章圖象變化.cpp－OnInvertColor()3真彩色圖像的顏色反相BGR

bgrb=255-Bg=255-Gr=255-R4真彩色圖像的顏色反相-反相每個(gè)圖象相素每個(gè)真彩色圖像像素?cái)?shù)據(jù)的三個(gè)顏色分量都作相同的計(jì)算voidInvertPixels(CImage*pImage,int

nMold){ BYTE *pPixelLine;

int

nLine,nByte,nBytesPerLine,nHeight;

nHeight=pImage->GetHeight();

nBytesPerLine=nWidth*pImage->GetBPP()/8; for(nLine=0;nLine<nHeight;nLine++){

pPixelLine=(BYTE*)pImage->GetPixelAddress(0,nLine);//得行首址

//真彩色圖像像素?cái)?shù)據(jù)的三個(gè)顏色分量作相同的計(jì)算

for(nByte=0;nByte<nBytesPerLine;nByte++)

pPixelLine[nByte]=nMold-pPixelLine[nByte]; }}5非真彩色圖像的顏色反相

RGBrgbb=255-Bg=255-Gr=255-R調(diào)色板調(diào)色板6非真彩色圖像顏色反相-反相調(diào)色板非真彩色圖像顏色反相只需修改調(diào)色板單元的數(shù)值

voidInvertPalette(CImage*pImage){

int

i,nColorTableEntries;

RGBQUAD

ColorTabs[256];//調(diào)色板

nColorTableEntries=pImage->GetMaxColorTableEntries();//取調(diào)色板項(xiàng)數(shù)

pImage->GetColorTable(0,nColorTableEntries,ColorTabs);//取調(diào)色板

//非真彩色圖像顏色反相只需修改調(diào)色板單元的數(shù)值

for(i=0;i<nColorTableEntries;i++) {

ColorTabs[i].rgbBlue=255-ColorTabs[i].rgbBlue;

ColorTabs[i].rgbGreen=255-ColorTabs[i].rgbGreen;

ColorTabs[i].rgbRed=255-ColorTabs[i].rgbRed; }

pImage->SetColorTable(0,nColorTableEntries,ColorTabs);//設(shè)置調(diào)色板}75.1.1-2.彩色圖像變黑白真彩色變黑白非真彩色變黑白8彩色圖像變黑白彩色圖像變黑白可通過(guò)(5.1.2)式進(jìn)行計(jì)算g=0.30r+0.59g+0.11b (5.1.2)真彩色圖像變黑白非真彩色圖像變黑白9真彩色圖像變黑白g=0.30r+0.59g+0.11b

真彩色圖像變換時(shí)RGB3分量都取g值。變換后的圖像并不是灰階圖像，其數(shù)據(jù)結(jié)構(gòu)還是原來(lái)的結(jié)構(gòu)，只是它們都取相同值因此外觀為灰色而已rgb

gggg=0.30r+0.59g+0.11b

g=0.30r+0.59g+0.11bg=0.30r+0.59g+0.11b

10真彩圖像變黑白voidPixelsChangedToGray(CImage*pImage){

int

nByte,j,i,nWidth,nHeight,nBytesPerPixel; BYTE *pPixelLine,cNewPixelValue;

nWidth=pImage->GetWidth(); nHeight=pImage->GetHeight();

nBytesPerPixel=pImage->GetBPP()/8; for(i=0;i<nHeight;i++){

pPixelLine=(BYTE*)pImage->GetPixelAddress(0,i);

nByte=0; for(j=0;j<nWidth;j++){ cNewPixelValue=(BYTE)(0.11*pPixelLine[nByte]+0.59*pPixelLine[nByte+1]+0.30*pPixelLine[nByte+2]);

pPixelLine[nByte]=pPixelLine[nByte+1]pPixelLine[nByte+2]=cNewPixelValue;

nByte+=nBytesPerPixel; } }}11非真彩色圖像變黑白g=0.30r+0.59g+0.11b

非真彩色圖像的色調(diào)由調(diào)色板決定，故變換只需在調(diào)色板數(shù)據(jù)中進(jìn)行調(diào)色板每項(xiàng)數(shù)據(jù)變灰像素?cái)?shù)據(jù)保持不變由于只修改調(diào)色板中的顏色數(shù)據(jù)，其強(qiáng)度未必為按序排列，故也不是灰階圖像12非真彩色圖像變黑白

rgbgggg=0.30r+0.59g+0.11bg=0.30r+0.59g+0.11bg=0.30r+0.59g+0.11b

調(diào)色板調(diào)色板13非真彩圖像變黑白voidPaletteChangedToGray(CImage*pImage){

RGBQUAD

ColorTabs[256];

int

i,nColorTableEntries,nNewGrayColor;

nColorTableEntries=pImage->GetMaxColorTableEntries();

pImage->GetColorTable(0,nColorTableEntries,ColorTabs); for(i=0;i<nColorTableEntries;i++){

nNewGrayColor=(int)(0.11*ColorTabs[i].rgbBlue+0.59*ColorTabs[i].rgbGreen

+0.30*ColorTabs[i].rgbRed);

ColorTabs[i].rgbBlue=(BYTE)nNewGrayColor;

ColorTabs[i].rgbGreen=(BYTE)nNewGrayColor;

ColorTabs[i].rgbRed=(BYTE)nNewGrayColor;

}

pImage->SetColorTable(0,nColorTableEntries,ColorTabs);}145.2.2幾何變換－水平鏡像水平鏡像同一行內(nèi)左右對(duì)應(yīng)的像素兩兩互換演示程序：圖象變化/幾何變換:水平鏡像Program第五章圖象變化.cpp－OnHorizontalFlip()15水平鏡像

0123012345612301230456123123Pixel(i,j)Pixel(nWidth-1-i,j)(1,2)(2,2)16水平鏡像voidHorizontalFlip(CImage*pNewImage,CImage*pImage){int

i,j,nByte,nWidth,nHeight,nBytesPerPixel,nBytesPerLine,nBitsPerPixel;DWORD

dwPixelValue;BYTE *pOldPixelLine,*pNewPixelLine,*pNew,*pOriginal;

nWidth=pImage->GetWidth(); nHeight=pImage->GetHeight();

nBitsPerPixel=pImage->GetBPP(); nBytesPerPixel=nBitsPerPixel/8;

CopyImage(pNewImage,pImage); for(i=0;i<nHeight;i++){

pOldPixelLine=(BYTE*)pImage->GetPixelAddress(0,i);

pNewPixelLine=(BYTE*)pNewImage->GetPixelAddress(0,i);

nByte=0; for(j=0;j<nWidth;j++){

pOriginal=pOldPixelLine+nByte;

pNew=pNewPixelLine+(nWidth-1)*nBytesPerPixel-nByte; memcpy(pNew,pOriginal,nBytesPerPixel);

nByte+=nBytesPerPixel; } }}175.2.2幾何變換－垂直鏡像垂直鏡像(留作作業(yè))同一列內(nèi)上下對(duì)應(yīng)的像素兩兩互換

0123012301230123Pixel(i,j)Pixel(i,Height-1-j)(1,2)(1,1)185.2.4幾何變換－整數(shù)倍放大(擴(kuò)展法)圖像的整數(shù)倍放大是指圖像的1個(gè)像素放大成1個(gè)n×n的矩形塊，粒子變粗但像素?cái)?shù)量不變。演示程序：圖象變化/幾何變換:放大1倍Program第五章圖象變化.cpp－OnZoomIn()012012012345012345Pixel(i,j)Pixel(2*i,2*j)Pixel(2*i,2*j+1)Pixel(2*i+1,2*j)Pixel(2*i+1,2*j+1)19整數(shù)倍放大voidZoomInImage(CImage*pNewImage,CImage*pImage,int

nTimesFactor){

inti,j,nRepeat,nWidth,nHeight,nNewWidth,nNewHeight,nBytesPerPixel,nBitsPerPixel;BYTE *pNewPixel,*pOriginalPixel;

nWidth=pImage->GetWidth(); nHeight=pImage->GetHeight();

nNewWidth=pImage->GetWidth()*nTimesFactor;

nNewHeight=pImage->GetHeight()*nTimesFactor;

nBitsPerPixel=pImage->GetBPP(); nBytesPerPixel=nBitsPerPixel/8;

pNewImage->Create(nNewWidth,nNewHeight,nBitsPerPixel,0););//建立放大的圖像

CopyColorTables(pNewImage,pImage);//復(fù)制調(diào)色板

for(i=0;i<nNewHeight;i++){

pOriginalPixel=(BYTE*)pImage->GetPixelAddress(0,i/nTimesFactor);//得原圖行首址

pNewPixel=(BYTE*)pNewImage->GetPixelAddress(0,i);//得新圖行首址

for(j=0;j<nWidth;j++){

for(nRepeat=0;nRepeat<nTimesFactor;nRepeat++) {

memcpy(pNewPixel,pOriginalPixel,nBytesPerPixel);//復(fù)制像素?cái)?shù)據(jù)

pNewPixel+=nBytesPerPixel; }

pOriginalPixel+=nBytesPerPixel; }}}20幾何變換－整數(shù)倍縮小(跳點(diǎn)法)整數(shù)倍縮小用跳點(diǎn)方式實(shí)現(xiàn)(留作作業(yè))012012012345012345Pixel(i,j)Pixel(i/2,j/2)(2,1)(4,2)215.3圖像的非整數(shù)倍縮放由于圖像的離散性，非整數(shù)倍縮放后計(jì)算出的坐標(biāo)值不一定是整數(shù)，故需要重新決定整數(shù)坐標(biāo)值。常用的方法是：最近鄰點(diǎn)法坐標(biāo)的計(jì)算結(jié)果作四舍五入處理，得到它最接近的點(diǎn)的坐標(biāo)。雙線性內(nèi)插法在xy兩個(gè)方向上作線性內(nèi)插，靠得近的像素的權(quán)值取得大，離得遠(yuǎn)的像素的權(quán)值取得小。(1,1)(1.67,1.67)335522逆向算法

設(shè)原圖像為f(x,y)，幾何變換后的新圖像為g(u,v)，則由像素的x、y坐標(biāo)計(jì)算變換后對(duì)應(yīng)的u、v坐標(biāo)的計(jì)算稱為正向計(jì)算。u=Fu(x,y) (5.6.1)v=Fv(x,y) (5.6.2)為了避免新圖像中像素的遺漏，通常采用逆向算法。坐標(biāo)轉(zhuǎn)換計(jì)算中，u、v應(yīng)遍歷新圖像中的每一個(gè)像素。x=Fx(u,v) (5.6.3)y=Fy(u,v) (5.6.4)(1,1)(1.67,1.67)3355正向計(jì)算逆向算法23最近鄰點(diǎn)法

坐標(biāo)的計(jì)算結(jié)果作四舍五入處理，得到它最接近的點(diǎn)的坐標(biāo)。為了防止顏色失真，真彩色圖像的幾何變換只能采用最近鄰點(diǎn)法演示程序：幾何變換/非整數(shù)倍縮放(1.3倍)Program第五章圖象編程.cpp－ScaleByCloser()(x,y)(x,y)(x+1,y)(x+1,y+1)(x,y+1)24voidScaleByCloser(CImage*pDestImage,CImage*pSourceImage,double

dMultiple){

nWidth=pSourceImage->GetWidth(); nHeight=pSourceImage->GetHeight();

nNewWidth=(int)(nWidth*dMultiple); nNewHeight=(int)(nHeight*dMultiple);

nBytesPerPixel=pSourceImage->GetBPP()/8;

pDestImage->Create(nNewWidth,nNewHeight,pSourceImage->GetBPP(),0);

CopyColorTables(pDestImage,pSourceImage); for(nYInNew=0;nYInNew<nNewHeight;nYInNew++) {

dYInOld=(double)nYInNew/dMultiple;

nOldY=(int)dYInOld;

dYFraction=dYInOld-(double)nOldY; if(dYFraction>0.5&&nOldY<nHeight-1)

nOldY++; for(nXInNew=0;nXInNew<nNewWidth;nXInNew++){

dXInOld=(double)nXInNew/dMultiple; nOldX=(int)dXInOld;

dXFraction=dXInOld-(double)nOldX; if(dXFraction>0.5&&nOldX<nWidth-1)

nOldX++;

pNewPixel=(BYTE*)pDestImage->GetPixelAddress(nXInNew,nYInNew);

pPixel=(BYTE*)pSourceImage->GetPixelAddress(nOldX,nOldY); memcpy(pNewPixel,pPixel,nBytesPerPixel); } }}25雙線性內(nèi)插法

(x,y)點(diǎn)處灰度值的計(jì)算公式如下：

p=

x–X (5.7.1)q=y-Y (5.7.2)

f(x,y)=(1-q)[(1-p)f(X,Y)+p

f(X+1,Y)]+q[(1-p)f(X,Y+1)+p

f(X+1,Y+1)] (5.7.3)灰階圖像采用雙線性內(nèi)插法實(shí)現(xiàn)生成的圖像灰度變化平緩柔和，沒有不連續(xù)的缺點(diǎn)。演示程序：幾何變換/非整數(shù)倍縮放(1.3倍)Program第五章圖象編程.cpp－ScaleByTwoLinear()(x,y)(X,Y)(X+1,Y)(X+1,Y+1)(X,Y+1)1-ppq1-q26voidScaleByTwoLinear(CImage*pDestImage,CImage*pSourceImage,double

dMultiple){

dwUpLeft=dwUpRight=dwDownLeft=dwDownRight=dwPixelValue=0;

nWidth=pSourceImage->GetWidth(); nHeight=pSourceImage->GetHeight();

nNewWidth=(int)(nWidth*dMultiple); nNewHeight=(int)(nHeight*dMultiple);

nBytesPerPixel=pSourceImage->GetBPP()/8;

pDestImage->Create(nNewWidth,nNewHeight,pSourceImage->GetBPP());

CopyColorTables(pDestImage,pSourceImage);for(nYInNew=0;nYInNew<nNewHeight;nYInNew++){

nY=(int)(nYInNew/dMultiple);

if(nY+1>=nHeight)

nY=nHeight-2; for(nXInNew=0;nXInNew<nNewWidth;nXInNew++){

nX=(int)(nXInNew/dMultiple);

if(nX+1>=nWidth)

nX=nWidth-2;

dX=(double)nXInNew/dMultiple; dY=(double)nYInNew/dMultiple;

dXFraction=dX-nX; dYFraction=dY-nY;27

pPixel=(BYTE*)pSourceImage->GetPixelAddress(nX,nY);

memcpy(&dwUpLeft,pPixel,nBytesPerPixel);

pPixel=(BYTE*)pSourceImage->GetPixelAddress(nX+1,nY);

memcpy(&dwUpRight,pPixel,nBytesPerPixel);

pPixel=(BYTE*)pSourceImage->GetPixelAddress(nX,nY+1);

memcpy(&dwDownLeft,pPixel,nBytesPerPixel);

pPixel=(BYTE*)pSourceImage->GetPixelAddress(nX+1,nY+1);

memcpy(&dwDownRight,pPixel,nBytesPerPixel);

dXWeigh=(1-dXFraction)*dwUpLeft+dXFraction*dwUpRight;

dYWeigh=(1-dXFraction)*dwDownLeft+dXFraction*dwDownRight;

dwPixelValue=(COLORREF)((1-dYFraction)*dXWeigh+dYFraction*dYWeigh);

pNewPixel=(BYTE*)pDestImage->GetPixelAddress(nXInNew,nYInNew);

memcpy(pNewPixel,&dwPixelValue,nBytesPerPixel);}}}285.2.5幾何變換－旋轉(zhuǎn)順時(shí)針旋轉(zhuǎn)90度通過(guò)行列數(shù)據(jù)的交換來(lái)實(shí)現(xiàn)演示程序：圖象變化/幾何變換:順時(shí)針旋轉(zhuǎn)90度Program第五章圖象變化.cpp－OnRotate90Clockwise()0120123401234012(2,1)(3,2)Pixel(x,y)Pixel(OldHeigh-1-y,x)OldHeighxyyX？29順時(shí)針旋轉(zhuǎn)90度voidRotate90Clockwise(CImage*pNewImage,CImage*pImage){

int

nBytesPerPixel,nWidth,nHeight,nX,