正确版本：矩阵做dct

#include <iostream>

#include <math.h>

using namespace std;



#define NUM 8

#define PI 3.1415926






// DCT - Discrete Cosine Transform

void DCT(short data[NUM][NUM])

{



	short output[NUM][NUM];

	double ALPHA, BETA;



	short u = 0;

	short v = 0;

	short i = 0;

	short j = 0;



	for (u = 0; u < NUM; u++)

	{

		for (v = 0; v < NUM; v++)

		{

			if (u == 0)

			{

				ALPHA = sqrt(1.0 / NUM);

			}

			else

			{

				ALPHA = sqrt(2.0 / NUM);

			}



			if (v == 0)

			{

				BETA = sqrt(1.0 / NUM);

			}

			else

			{

				BETA = sqrt(2.0 / NUM);

			}



			double tmp = 0.0;

			for (i = 0; i < NUM; i++)

			{

				for (j = 0; j < NUM; j++)

				{

					tmp += data[i][j] * cos((2 * i + 1)*u*PI / (2.0 * NUM)) * cos((2 * j + 1)*v*PI / (2.0 * NUM));

				}

			}

			output[u][v] = ALPHA * BETA * tmp;

		}

	}



	memset(data, 0, NUM * NUM * sizeof(short));

	memcpy(data, output, NUM * NUM * sizeof(short));

}



// Inverse DCT

void IDCT(short data[NUM][NUM])

{

	short output[NUM][NUM];

	double ALPHA, BETA;



	short u = 0;

	short v = 0;

	short i = 0;

	short j = 0;



	for (i = 0; i < NUM; i++)

	{

		for (short j = 0; j < NUM; j++)

		{

			double tmp = 0.0;



			for (short u = 0; u < NUM; u++)

			{

				for (v = 0; v < NUM; v++)

				{

					if (u == 0)

					{

						ALPHA = sqrt(1.0 / NUM);

					}

					else

					{

						ALPHA = sqrt(2.0 / NUM);

					}

					if (v == 0)

					{

						BETA = sqrt(1.0 / NUM);

					}

					else

					{

						BETA = sqrt(2.0 / NUM);

					}

					tmp += ALPHA * BETA * data[u][v] * cos((2 * i + 1)*u*PI / (2.0 * NUM)) * cos((2 * j + 1)*v*PI / (2.0 * NUM));

				}

			}

			output[i][j] = round(tmp);

		}

	}

	memset(data, 0, NUM * NUM * sizeof(short));

	memcpy(data, output, NUM * NUM * sizeof(short));

}



int main(void)

{

	short i = 0;

	short j = 0;

	short u = 0;

	short v = 0;



	// 8 x 8 的图像数据

	short input[NUM][NUM] =

	{

		{ 89, 101, 114, 125, 126, 115, 105, 96 },

		{ 97, 115, 131, 147, 149, 135, 123, 113 },

		{ 114, 134, 159, 178, 175, 164, 149, 137 },

		{ 121, 143, 177, 196, 201, 189, 165, 150 },

		{ 119, 141, 175, 201, 207, 186, 162, 144 },

		{ 107, 130, 165, 189, 192, 171, 144, 125 },

		{ 97, 119, 149, 171, 172, 145, 117, 96 },

		{ 88, 107, 136, 156, 155, 129, 97, 75 }

	};



	DCT(input);

	cout << "The result of DCT:" << endl;

	for (u = 0; u < NUM; u++)

	{

		for (v = 0; v < NUM; v++)

		{

			cout << input[u][v] << " ";

		}

		cout << endl;

	}



	IDCT(input);

	cout << "The result of IDCT:" << endl;

	for (i = 0; i < NUM; i++)

	{

		for (short j = 0; j < NUM; j++)

		{

			cout << input[i][j] << " ";

		}

		cout << endl;

	}



	return 0;

}

运行截图：

from:

https://blog.csdn.net/lwfcgz/article/details/8040550/