DCT蝶形运算java实现

DCT运算实现，其原理是离散余弦算法。将信号转到频域中。

以下代码经验证是正确的

代码如下，包括对一维数据和二维数据：

<pre name="code" class="java">/** * author:vivian * 时间：2015.5.28 * 版本：第一版 * 功能：8点快速傅里叶运算，用的是蝶形运算方法 *  * 各方法的功能 * 1）IntDCT1D针对的是一维的数据，进行8点蝶形运算 * 2）I_IntDCT1D一维数据的8点蝶形逆运算 * 3）IntDCT2D针对的是二维的数据，进行8点蝶形运算 * 4）I_IntDCT1D二维数据的8点蝶形逆运算*/

public class DCT2D{public void IntDCT1D(int data[]){////       input   x0 x1 ... x7////       output  X0 X2 X4 X6 X1 X3 X5 X7////  int datatmp[] = new int [8];datatmp[0] = data[0] + data[7];datatmp[1] = data[1] + data[6];datatmp[2] = data[2] + data[5];datatmp[3] = data[3] + data[4];datatmp[4] = data[3] - data[4];datatmp[5] = data[2] - data[5];datatmp[6] = data[1] - data[6];datatmp[7] = data[0] - data[7];//蝶形运算结束data[0] = datatmp[0] + datatmp[3];data[1] = datatmp[1] + datatmp[2];data[2] = datatmp[1] - datatmp[2];data[3] = datatmp[0] - datatmp[3];data[0] += data[1];                    //// data[0] = X0data[1] = - data[1] + ((data[0])>>1);     /// data[1] = X4data[3] = data[3] - (data[2] >>1) - (data[2] >>3); data[2] += data[3];data[3] = data[3] - (data[2] >>1) - (data[2] >>3); // data[2] = X2    data[3] = X6datatmp[5] = datatmp[5] - (datatmp[6] >>1) + (datatmp[6] >>4);datatmp[6] = datatmp[6] + (datatmp[5] >>1) + (datatmp[5] >>2);datatmp[5] = - datatmp[5] + (datatmp[6] >>1) - (datatmp[6] >>4);data[4] = datatmp[4] + datatmp[5];data[5] = datatmp[4] - datatmp[5];data[6] = -datatmp[6] + datatmp[7];data[7] = datatmp[6] + datatmp[7];data[7] = data[7] - (data[4] >>1) -(data[4] >>2) -(data[4] >>4);data[4] = data[4] + data[7];data[7] = data[7] - (data[4] >>1) -(data[4] >>2) -(data[4] >>4);// data[4] = X1      data[7] = X7data[6] = data[6] - (data[5] >>2);data[5] = data[5] + (data[6] >>1);data[6] = data[6] - (data[5] >>2);// data[5] = X3    data[7] = X5/*   datatmp[0] = data[0];            datatmp[1] = data[2];datatmp[2] = data[1];    datatmp[3] = data[3];datatmp[4] = data[4];    datatmp[5] = data[6];datatmp[6] = data[5];    datatmp[7] = data[7];*/datatmp[0] = data[0];    datatmp[1] = data[4];datatmp[2] = data[2];    datatmp[3] = data[6];datatmp[4] = data[1];    datatmp[5] = data[5];datatmp[6] = data[3];    datatmp[7] = data[7];int i;for (i=0; i<8; i++)  data[i] = datatmp[i];}void I_IntDCT1D(int data[]){//////////        input X0, X2, X4, X6, X1, X3, X5, X7           ////      output x0, x1,x2, ..., x7int datatmp[] = new int [8];int i;for (i=0; i<8; i++)  datatmp[i] = data[i];data[0] = datatmp[0];    data[1] = datatmp[2];data[2] = datatmp[4];    data[3] = datatmp[6] ;data[4] = datatmp[1];    data[5] = datatmp[3];data[6] = datatmp[5];    data[7] = datatmp[7];datatmp[1] = - data[2] + (data[0]>>1);datatmp[0] = data[0] - datatmp[1];datatmp[3] = data[3] + (data[1] >>1) +(data[1] >>3);datatmp[2] = data[1] - datatmp[3];datatmp[3] = datatmp[3] +(datatmp[2] >>1) +(datatmp[2] >>3);datatmp[6] = data[5] + (data[6] >>2);datatmp[5] = data[6] - (datatmp[6] >>1);datatmp[6] = datatmp[6] + (datatmp[5] >>2);datatmp[7] = data[7] + (data[4] >>1) + (data[4] >>2) + (data[4] >>4);datatmp[4] = data[4] - datatmp[7];datatmp[7] = datatmp[7] + (datatmp[4] >>1) + (datatmp[4] >>2) + (datatmp[4] >>4);// four inverse lifting stepdata[0] = (datatmp[0] + datatmp[3]) >>1;data[3] = (datatmp[0] - datatmp[3]) >>1;data[1] = (datatmp[1] + datatmp[2]) >>1;data[2] = (datatmp[1] - datatmp[2]) >>1;data[4] = (datatmp[4] + datatmp[5]) >>1;data[5] = (datatmp[4] - datatmp[5]) >>1;data[6] = (- datatmp[6] + datatmp[7]) >>1;data[7] = (datatmp[6] + datatmp[7]) >>1;// four inverse butterflydata[5] = - data[5] + (data[6] >>1) - (data[6] >>4);data[6] = data[6] - (data[5] >>1) - (data[5] >>2);data[5] = data[5] + (data[6] >>1) - (data[6] >>4);/////////////////datatmp[0] = (data[0] + data[7]) >>1;datatmp[1] = (data[1] + data[6]) >>1;datatmp[2] = (data[2] + data[5]) >>1;datatmp[3] = (data[3] + data[4]) >>1;datatmp[4] = (data[3] - data[4]) >>1;datatmp[5] = (data[2] - data[5]) >>1;datatmp[6] = (data[1] - data[6]) >>1;datatmp[7] = (data[0] - data[7]) >>1;//int i;for(i=0; i<8; i++) data[i] = datatmp[i];}public void IntDCT2D(int data[][], int height, int width){int nheight, nwidth;int i, j, k, l;int ni, nj;   //纪录处理数据的位置int datatmp[] = new int [8];nheight = height >>3;nwidth = width >>3;ni = 0;for (i=0; i<nheight; i++){nj = 0;for (j=0; j<nwidth; j++){//对行做变换for (k=0; k<8; k++){for (l=0; l<8; l++)datatmp[l] = data[ni+k][nj+l];IntDCT1D(datatmp);for (l=0; l<8; l++)data[ni+k][nj+l] = datatmp[l];}////对列做变换for (k=0; k<8; k++){for (l=0; l<8; l++)datatmp[l] = data[ni+l][nj+k];IntDCT1D(datatmp);for (l=0; l<8; l++)data[ni+l][nj+k] = datatmp[l];}nj = nj + 8;}ni = ni + 8;}}publicvoid I_IntDCT2D(int data[][], int height, int width){int nheight, nwidth;int i, j, k, l;int ni, nj;   //纪录处理数据的位置int datatmp[] = new int [8];nheight = height >>3;nwidth = width >>3;ni = 0;for (i=0; i<nheight; i++){nj = 0;for (j=0; j<nwidth; j++){////对列做反变换for (k=0; k<8; k++){for (l=0; l<8; l++)datatmp[l] = data[ni+l][nj+k];I_IntDCT1D(datatmp);for (l=0; l<8; l++)data[ni+l][nj+k] = datatmp[l];}//对行做反变换for (k=0; k<8; k++){for (l=0; l<8; l++)datatmp[l] = data[ni+k][nj+l];I_IntDCT1D(datatmp);for (l=0; l<8; l++)data[ni+k][nj+l] = datatmp[l];}nj = nj + 8;}ni = ni + 8;}}}