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#include <stdio.h>
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#include <time.h>
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// 应用优化后的可分离高斯模糊到给定的二维数组src上,并将结果存到二维数组dst中
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void applySeparableGaussianBlur(float src[][5], float dst[][5], int h, int w, float kx[3], float ky[3]) {
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float buf[3][3]; // 提前声明buf数组,符合C89要求
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int i, j; // 提前声明循环中使用的变量,符合C89要求
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// 初始化buf数组为0
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for (i = 0; i < 3; ++i) {
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for (j = 0; j < 3; ++j) {
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buf[i][j] = 0;
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}
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}
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// 宏定义,用于循环利用buf数组的3个行缓冲区,通过模运算确保索引值在0~2之间
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#define IDX(n) ((n) % 3)
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// 循环计算前两行的行内卷积并存储在buf中
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for (i = 0; i < 2; ++i) {
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for (j = 1; j < w - 1; ++j) {
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buf[i][j] = src[i][j - 1] * kx[0] + src[i][j] * kx[1] + src[i][j + 1] * kx[2];
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}
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}
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// 开始进行可分离卷积
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for (i = 1; i < h - 1; ++i) {
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// 计算当前行的行内卷积
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for (j = 1; j < w - 1; ++j) {
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buf[IDX(i)][j] = src[i][j - 1] * kx[0] + src[i][j] * kx[1] + src[i][j + 1] * kx[2];
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}
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// 进行行间的卷积得到最终像素值
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for (j = 1; j < w - 1; ++j) {
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dst[i][j] = buf[IDX(i - 1)][j] * ky[0] + buf[IDX(i)][j] * ky[1] + buf[IDX(i + 1)][j] * ky[2];
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}
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}
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#undef IDX
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}
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// 原始的应用3x3 GaussianBlur函数(与之前代码中的类似,方便对比用时)
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void applyGaussianBlur(float src[][5], float dst[][5], int h, int w, float kernel[3][3]) {
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int i, j; // 提前声明循环变量,符合C89要求
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for (i = 1; i < h - 1; ++i) {
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for (j = 1; j < w - 1; ++j) {
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dst[i][j] =
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src[i - 1][j - 1] * kernel[0][0] + src[i - 1][j] * kernel[0][1] + src[i - 1][j + 1] * kernel[0][2] +
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src[i][j - 1] * kernel[1][0] + src[i][j] * kernel[1][1] + src[i][j + 1] * kernel[1][2] +
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src[i + 1][j - 1] * kernel[2][0] + src[i + 1][j] * kernel[2][1] + src[i + 1][j + 1] * kernel[2][2];
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}
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}
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}
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int main() {
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float inputImage[5][5] = {
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{1, 2, 3, 4, 5},
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{6, 7, 8, 9, 10},
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{11, 12, 13, 14, 15},
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{16, 17, 18, 19, 20},
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{21, 22, 23, 24, 25}
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};
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float kernel[3][3] = {
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{1.0f / 16, 2.0f / 16, 1.0f / 16},
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{2.0f / 16, 4.0f / 16, 2.0f / 16},
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{1.0f / 16, 2.0f / 16, 1.0f / 16}
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};
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float kx[3] = { 0.25f, 0.5f, 0.25f };
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float ky[3] = { 0.25f, 0.5f, 0.25f };
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float outputImage1[5][5]; // 存放原始GaussianBlur结果
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float outputImage2[5][5]; // 存放优化后的可分离GaussianBlur结果
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int i, j; // 提前声明循环变量,符合C89要求
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// 原始GaussianBlur计时开始
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clock_t start_time1 = clock();
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applyGaussianBlur(inputImage, outputImage1, 5, 5, kernel);
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clock_t end_time1 = clock();
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double elapsed_time1 = ((double)(end_time1 - start_time1)) / CLOCKS_PER_SEC;
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// 优化后的可分离GaussianBlur计时开始
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clock_t start_time2 = clock();
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applySeparableGaussianBlur(inputImage, outputImage2, 5, 5, kx, ky);
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clock_t end_time2 = clock();
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double elapsed_time2 = ((double)(end_time2 - start_time2)) / CLOCKS_PER_SEC;
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// 输出原始GaussianBlur结果
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printf("原始GaussianBlur后的图像矩阵:\n");
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for (i = 0; i < 5; ++i) {
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for (j = 0; j < 5; ++j) {
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printf("%.2f ", outputImage1[i][j]);
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}
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printf("\n");
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}
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printf("原始GaussianBlur运行时间:%.6f 秒\n", elapsed_time1);
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// 输出优化后的可分离GaussianBlur结果
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printf("优化后的可分离GaussianBlur后的图像矩阵:\n");
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for (i = 0; i < 5; ++i) {
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for (j = 0; j < 5; ++j) {
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printf("%.2f ", outputImage2[i][j]);
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}
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printf("\n");
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}
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printf("优化后的可分离GaussianBlur运行时间:%.6f 秒\n", elapsed_time2);
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return 0;
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}
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