李現(xiàn)路:DSP6000圖像位置移動(dòng)與變形的典型算法（四）

五、圖像的旋轉(zhuǎn)實(shí)驗(yàn)

數(shù)學(xué)表達(dá)式原理：

下面我們來(lái)推導(dǎo)一下旋轉(zhuǎn)運(yùn)算的變換公式。如下圖所示，點(diǎn)（x0，y0）經(jīng)過(guò)旋轉(zhuǎn)θ度后

坐標(biāo)變成（x1，y1）。其數(shù)學(xué)表達(dá)式為：

X0=x1cos(θ)+y1sin(θ)+ccos(θ)-dsin(θ)+a ;

Y0=-xsin(θ)+y1cos(θ)+csin(θ)-dcos(θ)+ b

算法的C語(yǔ)言代碼：

/*圖像旋轉(zhuǎn)參數(shù)*/

Float fAngle=3.1415927/3; //旋轉(zhuǎn)的角度

*畫(huà)矩形邊框函數(shù)*/

Void drawRectangle();

*計(jì)算圖像旋轉(zhuǎn)參數(shù)*/

Void computeParameter();

/*進(jìn)行圖像旋轉(zhuǎn)處理*/

void rotate()

{

         int i,j,intInc;

         int intCapYInc;

         int intCapX,intCapY;

         /*進(jìn)行圖像旋轉(zhuǎn)，重新賦值*/

         //方框內(nèi)奇數(shù)行

         for(i=intALines;i<intDLines;i++)

         {

             for(j=intAPixels;j<intDPixels;j++)

             {

            intInc = i*2;  

            intCapX    = (int)(j*cosAngle + intInc*sinAngle + f1 + 0.5);

            intCapYInc = (int)(intInc*cosAngle - j*sinAngle + f1 + 0.5);          

            if((intCapYInc%2)==0)

            {

                     intCapY = intCapYInc/2;

            }

            else

            {

                     intCapY = (intCapYInc-1)/2+numLines/2;

            }

            //判斷是否在原圖范圍內(nèi)

            if((intCapX>=0) && (intCapX<numPixels) && (intCapY>=0) && (intCapY<numLines))  

            {

                                //傳送亮度信號(hào)

                                *(Uint8 *)(tempYbuffer + i*numPixels + j) = *(Uint8 *)(capYbuffer + intCapY*numPixels + intCapX);                                                                         

                 }

            else

            {

                      *(Uint8 *)(tempYbuffer + i*numPixels + j) = 0xFF;

            }

                   }       

         }

         //方框內(nèi)偶數(shù)行

         for(i=numLines/2+intALines;i<numLines/2+intDLines;i++)

         {

             for(j=intAPixels;j<intDPixels;j++)

             {                

            intInc = (i-numLines/2)*2 + 1;

            intCapX    = (int)(j*cosAngle + intInc*sinAngle + f1 + 0.5);

            intCapYInc = (int)(intInc*cosAngle - j*sinAngle + f1 + 0.5);          

            if((intCapYInc%2)==0)

            {

                     intCapY = intCapYInc/2;

            }

            else

            {

                     intCapY = (intCapYInc-1)/2+numLines/2;

            }            

            //判斷是否在原圖范圍內(nèi)

            if((intCapX>=0) && (intCapX<numPixels) && (intCapY>=0) && (intCapY<numLines))  

            {

                                //傳送亮度信號(hào)

                                *(Uint8 *)(tempYbuffer + i*numPixels + j) = *(Uint8 *)(capYbuffer + intCapY*numPixels + intCapX);                                                                         

                 }

            else

            {

                      *(Uint8 *)(tempYbuffer + i*numPixels + j) = 0xFF;

            }

                   }       

         }       

}

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