[영상처리] DCT 계수

문제 다음 8 x 8 block image로부터 DCT 계수를 얻은 후에, DCT 계수 값을 print 해보세요 --------------------------------------------------------------------------------------------------------------- #define PI (3.14) // 8 x8 Y pixel value BYTE ff[8][8] ={  {137, 139, 139, 136, 134, 137, 145, 152 },                         {137, 137, 138, 138, 135, 136, 143, 152 },                         {137, 139 ,140, 139 ,134, 144, 145, 150 },                        {134, 140, 140, 138 ,140, 144, 145, 146},                        {137, 139, 141 ,136 ,134, 137, 145, 140 },                               {137, 139, 140, 140 ,144, 146, 144, 133},                       {140, 140, 142, 146, 148, 143, 134 ,128 },                       {142, 139, 139, 145, 149, 143, 132, 128 }} ; --------------------------------------------------------------------------------------------------------------- ff는 위의 grayscale data임 \(\boldsymbol{F(u,v) = \sum_{i=0}^{7}\sum_{j=0}^{7}f(i,j)cos(\frac{(2i+1)u\pi }{16})cos(\frac{(2j+1)u\pi }{16})}\) DCT 계수 값은?

1. 코드

	#define PI (3.14)
	int u, v;
	float F[8][8];

	// 8 x8 Y pixel value
	BYTE ff[8][8] = { {137, 139, 139, 136, 134, 137, 145, 152 },
					  {137, 137, 138, 138, 135, 136, 143, 152 },
					  {137, 139 ,140, 139 ,134, 144, 145, 150 },
					  {134, 140, 140, 138 ,140, 144, 145, 146},
					  {137, 139, 141 ,136 ,134, 137, 145, 140 },
					  {137, 139, 140, 140 ,144, 146, 144, 133},
					  {140, 140, 142, 146, 148, 143, 134 ,128 },
					 {142, 139, 139, 145, 149, 143, 132, 128 } };

	for (u = 0; u < 8; u++) {
		for (v = 0; v < 8; v++) {
			F[u][v] = 0.0;
			for (i = 0; i < 8; i++) {
				for (j = 0; j < 8; j++) {
					F[u][v] += ff[i][j] * cos((2 * i + 1) * u * PI / 16) * cos((2 * j + 1) * v * PI / 16);
				}
			}
			printf("%.0f ", F[u][v]);
		}
		printf("\n");
	}

2. 결과

8960 -46 -12 -4 -25 8 -4 3
9 -73 97 -63 -2 2 4 -6
-10 29 -19 8 33 -8 3 -2
-7 -0 7 -1 -14 9 -10 13
-16 -0 13 -6 -2 -4 -4 6
27 0 -19 6 -5 -9 3 -5
7 -11 3 12 -13 3 3 -5
-4 13 13 -11 -2 10 4 -3