c - 边缘检测（Sobel算子）需要C帮助
问题描述
我已经编写了两个不同的程序，但它们都不起作用，有人可以帮忙吗
int16_t gx[3] = {0, 0, 0};
int16_t gy[3] = {0, 0, 0};
int8_t matrix_gx[3][3] = {{-1,0,1},{-2,0,2},{-1,0,1}};
int8_t matrix_gy[3][3] = {{-1,-2,-1},{0,0,0},{1,2,1}};
for(int i = 0; i < height; i++)
{
for(int j = 0; j < width; j++)
{
for(int posx = -1; posx < 2; posx++) //-1 to +1 along x axis
{
for (int posy = -1; posy < 2; posy++) //-1 to +1 along y axis
{
//should do 9 elements 3x3 =9
if (((posx+i) >= 0) && ((posy+j) >= 0) && ((posx+i) <= height) && ((posy+j) <= width))
{
gx[0] += image[i + posx][j + posy].rgbtRed * matrix_gx[posx + 1][posy + 1];
gx[1] += image[i + posx][j + posy].rgbtGreen * matrix_gx[posx + 1][posy + 1];
gx[2] += image[i + posx][j + posy].rgbtBlue * matrix_gx[posx + 1][posy + 1];
gy[0] += image[i + posx][j + posy].rgbtRed * matrix_gy[posx + 1][posy + 1];
gy[1] += image[i + posx][j + posy].rgbtGreen * matrix_gy[posx + 1][posy + 1];
gy[2] += image[i + posx][j + posy].rgbtBlue * matrix_gy[posx + 1][posy + 1];
}
else
{
//adding 0 for the pixels that dont exist
gx[0] += (BYTE) 0;
gx[1] += (BYTE) 0;
gx[2] += (BYTE) 0;
gy[0] += (BYTE) 0;
gy[1] += (BYTE) 0;
gy[2] += (BYTE) 0;
}
}
//printf("%i %i", (BYTE) gx[0], (BYTE) gy[0]);
//printf(" %i %i", (BYTE) gx[1], (BYTE) gy[1]);
//printf(" %i %i \n",(BYTE) gx[2], (BYTE) gy[2]);
}
int G[3] = {0, 0, 0};
for (int o = 0; o < 3; o++)
{
G[o] = round(sqrt((gx[o] * gx[o]) + (gy[o] * gy[o])));
// printf("%i\n",G[o]);
if (G[o] > 256)
{
G[o] = 255;
}
else
{
G[o] = (BYTE) abs(G[o]);
}
}
//printf("%i ", (BYTE) G[0]);
image[i][j].rgbtRed = (BYTE) G[0];
//printf(" %i", (BYTE) G[1]);
image[i][j].rgbtGreen = (BYTE) G[1];
//printf(" %i\n", (BYTE) G[2]);
image[i][j].rgbtBlue = (BYTE) G[2];
}
}
该程序将输出作为完全白色的图像。我尝试使用 printf() 诊断错误。而且我看到 G[] 数组中的值是荒谬的，例如 30106 等，这些都是其他形式的二进制。当检查 G[] 是否溢出时，所有这些值都设置为 255，这给了我白色图像。printf() 输出
228 58 36 208 188 218
84 58 212 208 134 218
95 97 237 87 153 153
36365 //G[0] red pixel
29458 //G[1] green pixel
6577 //G[2] blue pixel
255 255 255 // notice how the pixels are set to 255 due to the overflow statement
第二个程序：这次我尝试只使用整数。我认为使用有符号到无符号转换可能存在冲突。
int matrix_gx[3][3] = {{-1, 0, 1}, {-2, 0, 2}, {-1, 0, 1}};
int matrix_gy[3][3] = {{-1, -2, -1}, {0, 0, 0}, {1, 2, 1}};
int gx[3] = {0, 0, 0};
int gy[3] = {0, 0, 0};
for (int h = 0; h < height; h++)
{
for (int w = 0; w < width; w++)
{
for (int x = -1; x < 2; x++) // grid with x from p-1 to p+1
{
for (int y = -1; y < 2; y++) // grid with y from p-1 to p+1
{
if ((h+x > 0)&&(h+x < height)&&(w+y > 0)&&(w+y < width))
{
//edge detection in x direction
//red color
gx[0] += image[h+x][w+y].rgbtRed * matrix_gx[x+1][y+1];
//green color
gx[1] += image[h+x][w+y].rgbtGreen * matrix_gx[x+1][y+1];
//blue color
gx[2] += image[h+x][w+y].rgbtBlue * matrix_gx[x+1][y+1];
//edge detection in the y direction
//red color
gy[0] += image[h+x][w+y].rgbtRed * matrix_gy[x+1][y+1];
//green color
gy[1] += image[h+x][w+y].rgbtGreen * matrix_gy[x+1][y+1];
//blue color
gy[2] += image[h+x][w+y].rgbtBlue * matrix_gy[x+1][y+1];
}
else
{
gx[0] = 0;
gx[1] = 0;
gx[2] = 0;
gy[0] = 0;
gy[1] = 0;
gy[2] = 0;
}
}
}
int G[3] = {0,0,0};
for (int i = 0; i < 3; i++)
{
G[i] = round(sqrt((float) (gx[i] * gx[i]) + (gy[i] * gy[i])));
//printf("%i ", G[i]);
if(G[i] > 256)
{
G[i] = 255;
}
//printf("%i\n", G[i]);
}
//assigning the pixels
image[h][w].rgbtRed = (BYTE) G[0];
image[h][w].rgbtGreen = (BYTE) G[1];
image[h][w].rgbtBlue = (BYTE) G[2];
}
}
这段代码的输出很奇怪，但我似乎取得了一些进展 这是第二个代码的输出。
