请写一个双线性插值算法,使用C语言实现,能够把长宽分别为8像素的灰度图像插值为长宽分别为32像素的灰度图像
时间: 2023-03-26 15:01:14 浏览: 76
双线性插值算法可以通过以下步骤实现:
1. 将目标图像的每个像素点坐标映射回原始图像中的坐标。
2. 对于每个目标像素点,找到其周围四个原始像素点,并计算其权重。
3. 根据权重和原始像素点的灰度值,计算目标像素点的灰度值。
具体实现代码如下:
```c
#include <stdio.h>
// 双线性插值算法
int bilinear_interpolation(unsigned char *src, int src_w, int src_h, unsigned char *dst, int dst_w, int dst_h) {
int x, y, x1, y1, x2, y2;
float fx, fy, w1, w2, w3, w4, val1, val2, val3, val4;
unsigned char *p1, *p2, *p3, *p4, *pdst;
for (y = ; y < dst_h; y++) {
fy = (float)y / (float)(dst_h - 1) * (float)(src_h - 1);
y1 = (int)fy;
y2 = y1 + 1;
if (y2 >= src_h) y2 = src_h - 1;
fy -= y1;
for (x = ; x < dst_w; x++) {
fx = (float)x / (float)(dst_w - 1) * (float)(src_w - 1);
x1 = (int)fx;
x2 = x1 + 1;
if (x2 >= src_w) x2 = src_w - 1;
fx -= x1;
p1 = src + y1 * src_w + x1;
p2 = src + y1 * src_w + x2;
p3 = src + y2 * src_w + x1;
p4 = src + y2 * src_w + x2;
w1 = (1.f - fx) * (1.f - fy);
w2 = fx * (1.f - fy);
w3 = (1.f - fx) * fy;
w4 = fx * fy;
val1 = (float)(*p1);
val2 = (float)(*p2);
val3 = (float)(*p3);
val4 = (float)(*p4);
pdst = dst + y * dst_w + x;
*pdst = (unsigned char)(w1 * val1 + w2 * val2 + w3 * val3 + w4 * val4 + .5f);
}
}
return ;
}
int main() {
unsigned char src[8][8] = {
{ 10, 20, 30, 40, 50, 60, 70, 80 },
{ 20, 30, 40, 50, 60, 70, 80, 90 },
{ 30, 40, 50, 60, 70, 80, 90, 100 },
{ 40, 50, 60, 70, 80, 90, 100, 110 },
{ 50, 60, 70, 80, 90, 100, 110, 120 },
{ 60, 70, 80, 90, 100, 110, 120, 130 },
{ 70, 80, 90, 100, 110, 120, 130, 140 },
{ 80, 90, 100, 110, 120, 130, 140, 150 }
};
unsigned char dst[32][32];
int i, j;
bilinear_interpolation((unsigned char *)src, 8, 8, (unsigned char *)dst, 32, 32);
for (i = ; i < 32; i++) {
for (j = ; j < 32; j++) {
printf("%d ", dst[i][j]);
}
printf("\n");
}
return ;
}
```