CS50 滤镜 'Edge' returns 白色图像

Question

我一直在研究哈佛的 CS50 'Filter' 问题，并且在 edges 部分遇到了一点问题。

我一直在尝试用这个算法来解决它：

逐个像素地浏览整个图像。图像是 RGBTRIPLE 类型的矩阵，称为 image[height][width]
检查当前像素是角点、边缘还是中间某处（'else' 情况）
将该像素和“相邻”像素与相应的 g(x) 和 g(y) 值相乘，计算 g(x)^2 + g(y)^2 的平方根，相应地对其进行舍入，并导出该值在另一个矩阵中 image2[height][width].

我在下面提供的代码是我解决问题的尝试。我使用了与 blur 算法中相同的验证（检查角、边或中间），它起作用了。

// Detect edges
void edges(int height, int width, RGBTRIPLE image[height][width])
{
    RGBTRIPLE gx, gy;
    RGBTRIPLE image2[height][width];

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            gx.rgbtRed = 0;
            gx.rgbtGreen = 0;
            gx.rgbtBlue = 0;

            gy.rgbtRed = 0;
            gy.rgbtGreen = 0;
            gy.rgbtBlue = 0;

            if (i == 0 && j == 0)
            {
                gx.rgbtRed += 0 * image[i][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gx.rgbtRed += 0 * image[i+1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i+1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i+1][j].rgbtBlue;

                gy.rgbtRed += 2 * image[i+1][j].rgbtRed;
                gy.rgbtGreen += 2 * image[i+1][j].rgbtGreen;
                gy.rgbtBlue += 2 * image[i+1][j].rgbtBlue;

                gx.rgbtRed += 2 * image[i][j+1].rgbtRed;
                gx.rgbtGreen += 2 * image[i][j+1].rgbtGreen;
                gx.rgbtBlue += 2 * image[i][j+1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j+1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j+1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j+1].rgbtBlue;

                gx.rgbtRed += image[i+1][j+1].rgbtRed;
                gx.rgbtGreen += image[i+1][j+1].rgbtGreen;
                gx.rgbtBlue += image[i+1][j+1].rgbtBlue;

                gy.rgbtRed += image[i+1][j+1].rgbtRed;
                gy.rgbtGreen += image[i+1][j+1].rgbtGreen;
                gy.rgbtBlue += image[i+1][j+1].rgbtBlue;
            }

            else if (i == 0 && j == width-1)
            {
                gx.rgbtRed += 0 * image[i][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gx.rgbtRed += -2 * image[i][j-1].rgbtRed;
                gx.rgbtGreen += -2 * image[i][j-1].rgbtGreen;
                gx.rgbtBlue += -2 * image[i][j-1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j-1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j-1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j-1].rgbtBlue;

                gx.rgbtRed += 0 * image[i+1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i+1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i+1][j].rgbtBlue;

                gy.rgbtRed += 2 * image[i+1][j].rgbtRed;
                gy.rgbtGreen += 2 * image[i+1][j].rgbtGreen;
                gy.rgbtBlue += 2 * image[i+1][j].rgbtBlue;

                gx.rgbtRed += -1 * image[i+1][j-1].rgbtRed;
                gx.rgbtGreen += -1 * image[i+1][j-1].rgbtGreen;
                gx.rgbtBlue += -1 * image[i+1][j-1].rgbtBlue;

                gy.rgbtRed += image[i+1][j-1].rgbtRed;
                gy.rgbtGreen += image[i+1][j-1].rgbtGreen;
                gy.rgbtBlue += image[i+1][j-1].rgbtBlue;
            }

            else if (i == height-1 && j == 0)
            {
                gx.rgbtRed += 0 * image[i][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gx.rgbtRed += 0 * image[i-1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i-1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i-1][j].rgbtBlue;

                gy.rgbtRed += -2 * image[i-1][j].rgbtRed;
                gy.rgbtGreen += -2 * image[i-1][j].rgbtGreen;
                gy.rgbtBlue += -2 * image[i-1][j].rgbtBlue;

                gx.rgbtRed += image[i-1][j+1].rgbtRed;
                gx.rgbtGreen += image[i-1][j+1].rgbtGreen;
                gx.rgbtBlue +=  image[i-1][j+1].rgbtBlue;

                gy.rgbtRed += -1 * image[i][j].rgbtRed;
                gy.rgbtGreen += -1 * image[i][j].rgbtGreen;
                gy.rgbtBlue += -1 * image[i][j].rgbtBlue;

                gx.rgbtRed += 2 * image[i][j+1].rgbtRed;
                gx.rgbtGreen += 2 * image[i][j+1].rgbtGreen;
                gx.rgbtBlue += 2 * image[i][j+1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j+1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j+1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j+1].rgbtBlue;
            }

            else if (i == height-1 && j == width-1)
            {
                gx.rgbtRed += 0 * image[i][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gx.rgbtRed += 0 * image[i-1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i-1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i-1][j].rgbtBlue;

                gy.rgbtRed += -2 * image[i-1][j].rgbtRed;
                gy.rgbtGreen += -2 * image[i-1][j].rgbtGreen;
                gy.rgbtBlue += -2 * image[i-1][j].rgbtBlue;

                gx.rgbtRed += -1 * image[i-1][j-1].rgbtRed;
                gx.rgbtGreen += -1 * image[i-1][j-1].rgbtGreen;
                gx.rgbtBlue += -1 * image[i-1][j-1].rgbtBlue;

                gy.rgbtRed += -1 * image[i-1][j-1].rgbtRed;
                gy.rgbtGreen += -1 * image[i-1][j-1].rgbtGreen;
                gy.rgbtBlue += -1 * image[i-1][j-1].rgbtBlue;

                gx.rgbtRed += -2 * image[i][j-1].rgbtRed;
                gx.rgbtGreen += -2 * image[i][j-1].rgbtGreen;
                gx.rgbtBlue += -2 * image[i][j-1].rgbtBlue;

                gy.rgbtRed += 0 * image[i-1][j-1].rgbtRed;
                gy.rgbtGreen += 0 * image[i-1][j-1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i-1][j-1].rgbtBlue;
            }

            else if (i == 0)
            {
                gx.rgbtRed += 0 * image[i][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gx.rgbtRed += -2 * image[i][j-1].rgbtRed;
                gx.rgbtGreen += -2 * image[i][j-1].rgbtGreen;
                gx.rgbtBlue += -2 * image[i][j-1].rgbtBlue;

                gy.rgbtRed += image[i][j-1].rgbtRed;
                gy.rgbtGreen += image[i][j-1].rgbtGreen;
                gy.rgbtBlue += image[i][j-1].rgbtBlue;

                gx.rgbtRed += -1 * image[i+1][j-1].rgbtRed;
                gx.rgbtGreen += -1 * image[i+1][j-1].rgbtGreen;
                gx.rgbtBlue += -1 * image[i+1][j-1].rgbtBlue;

                gy.rgbtRed += image[i+1][j-1].rgbtRed;
                gy.rgbtGreen += image[i+1][j-1].rgbtGreen;
                gy.rgbtBlue += image[i+1][j-1].rgbtBlue;

                gx.rgbtRed += 0 * image[i+1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i+1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i+1][j].rgbtBlue;

                gy.rgbtRed += 2 * image[i+1][j].rgbtRed;
                gy.rgbtGreen += 2 * image[i+1][j].rgbtGreen;
                gy.rgbtBlue += 2 * image[i+1][j].rgbtBlue;

                gx.rgbtRed += image[i+1][j+1].rgbtRed;
                gx.rgbtGreen += image[i+1][j+1].rgbtGreen;
                gx.rgbtBlue += image[i+1][j+1].rgbtBlue;

                gy.rgbtRed += image[i+1][j+1].rgbtRed;
                gy.rgbtGreen += image[i+1][j+1].rgbtGreen;
                gy.rgbtBlue += image[i+1][j+1].rgbtBlue;

                gx.rgbtRed += 2 * image[i][j+1].rgbtRed;
                gx.rgbtGreen += 2 * image[i][j+1].rgbtGreen;
                gx.rgbtBlue += 2 * image[i][j+1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j+1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j+1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j+1].rgbtBlue;
            }

            else if (i == height-1)
            {
                gx.rgbtRed += 0 * image[i][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gx.rgbtRed += -2 * image[i][j-1].rgbtRed;
                gx.rgbtGreen += -2 * image[i][j-1].rgbtGreen;
                gx.rgbtBlue += -2 * image[i][j-1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j-1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j-1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j-1].rgbtBlue;

                gx.rgbtRed += -1 * image[i-1][j-1].rgbtRed;
                gx.rgbtGreen += -1 * image[i-1][j-1].rgbtGreen;
                gx.rgbtBlue += -1 * image[i-1][j-1].rgbtBlue;

                gy.rgbtRed += -1 * image[i-1][j-1].rgbtRed;
                gy.rgbtGreen += -1 * image[i-1][j-1].rgbtGreen;
                gy.rgbtBlue += -1 * image[i-1][j-1].rgbtBlue;

                gx.rgbtRed += 0 * image[i-1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i-1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i-1][j].rgbtBlue;

                gy.rgbtRed += -2 * image[i-1][j].rgbtRed;
                gy.rgbtGreen += -2 * image[i-1][j].rgbtGreen;
                gy.rgbtBlue += -2 * image[i-1][j].rgbtBlue;

                gx.rgbtRed += image[i-1][j+1].rgbtRed;
                gx.rgbtGreen += image[i-1][j+1].rgbtGreen;
                gx.rgbtBlue += image[i-1][j+1].rgbtBlue;

                gy.rgbtRed += 0 * image[i-1][j+1].rgbtRed;
                gy.rgbtGreen += 0 * image[i-1][j+1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i-1][j+1].rgbtBlue;

                gx.rgbtRed += 2 * image[i][j+1].rgbtRed;
                gx.rgbtGreen += 2 * image[i][j+1].rgbtGreen;
                gx.rgbtBlue += 2 * image[i][j+1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j+1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j+1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j+1].rgbtBlue;
            }

            else if (j == 0)
            {
                gx.rgbtRed += 0 * image[i][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gx.rgbtRed += 0 * image[i-1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i-1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i-1][j].rgbtBlue;

                gy.rgbtRed += -2 * image[i-1][j].rgbtRed;
                gy.rgbtGreen += -2 * image[i-1][j].rgbtGreen;
                gy.rgbtBlue += -2 * image[i-1][j].rgbtBlue;

                gx.rgbtRed += image[i-1][j+1].rgbtRed;
                gx.rgbtGreen += image[i-1][j+1].rgbtGreen;
                gx.rgbtBlue += image[i-1][j+1].rgbtBlue;

                gy.rgbtRed += -1 * image[i-1][j+1].rgbtRed;
                gy.rgbtGreen += -1 * image[i-1][j+1].rgbtGreen;
                gy.rgbtBlue += -1 * image[i-1][j+1].rgbtBlue;

                gx.rgbtRed += 2 * image[i][j+1].rgbtRed;
                gx.rgbtGreen += 2 * image[i][j+1].rgbtGreen;
                gx.rgbtBlue += 2 * image[i][j+1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j+1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j+1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j+1].rgbtBlue;

                gx.rgbtRed += image[i+1][j+1].rgbtRed;
                gx.rgbtGreen += image[i+1][j+1].rgbtGreen;
                gx.rgbtBlue += image[i+1][j+1].rgbtBlue;

                gy.rgbtRed += image[i+1][j+1].rgbtRed;
                gy.rgbtGreen += image[i+1][j+1].rgbtGreen;
                gy.rgbtBlue += image[i+1][j+1].rgbtBlue;

                gx.rgbtRed += 0 * image[i+1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i+1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i+1][j].rgbtBlue;

                gy.rgbtRed += 2 * image[i+1][j].rgbtRed;
                gy.rgbtGreen += 2 * image[i+1][j].rgbtGreen;
                gy.rgbtBlue += 2 * image[i+1][j].rgbtBlue;
            }

            else if (j == width-1)
            {
                gx.rgbtRed += 0 * image[i][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gx.rgbtRed += 0 * image[i-1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i-1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i-1][j].rgbtBlue;

                gy.rgbtRed += -2 * image[i-1][j].rgbtRed;
                gy.rgbtGreen += -2 * image[i-1][j].rgbtGreen;
                gy.rgbtBlue += -2 * image[i-1][j].rgbtBlue;

                gx.rgbtRed += -1 * image[i-1][j-1].rgbtRed;
                gx.rgbtGreen += -1 * image[i-1][j-1].rgbtGreen;
                gx.rgbtBlue += -1 * image[i-1][j-1].rgbtBlue;

                gy.rgbtRed += -1 * image[i-1][j-1].rgbtRed;
                gy.rgbtGreen += -1 * image[i-1][j-1].rgbtGreen;
                gy.rgbtBlue += -1 * image[i-1][j-1].rgbtBlue;

                gx.rgbtRed += -2 * image[i][j-1].rgbtRed;
                gx.rgbtGreen += -2 * image[i][j-1].rgbtGreen;
                gx.rgbtBlue += -2 * image[i][j-1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j-1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j-1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j-1].rgbtBlue;

                gx.rgbtRed += -1 * image[i+1][j-1].rgbtRed;
                gx.rgbtGreen += -1 * image[i+1][j-1].rgbtGreen;
                gx.rgbtBlue += -1 * image[i+1][j-1].rgbtBlue;

                gy.rgbtRed += image[i+1][j-1].rgbtRed;
                gy.rgbtGreen += image[i+1][j-1].rgbtGreen;
                gy.rgbtBlue += image[i+1][j-1].rgbtBlue;

                gx.rgbtRed += 0 * image[i+1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i+1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i+1][j].rgbtBlue;

                gy.rgbtRed += 2 * image[i+1][j].rgbtRed;
                gy.rgbtGreen += 2 * image[i+1][j].rgbtGreen;
                gy.rgbtBlue += 2 * image[i+1][j].rgbtBlue;
            }

            else
            {
                gx.rgbtRed += 0 * image[i][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j].rgbtBlue;

                gx.rgbtRed += -1 * image[i-1][j-1].rgbtRed;
                gx.rgbtGreen += -1 * image[i-1][j-1].rgbtGreen;
                gx.rgbtBlue += -1 * image[i-1][j-1].rgbtBlue;

                gy.rgbtRed += -1 * image[i-1][j-1].rgbtRed;
                gy.rgbtGreen += -1 * image[i-1][j-1].rgbtGreen;
                gy.rgbtBlue += -1 * image[i-1][j-1].rgbtBlue;

                gx.rgbtRed += 0 * image[i-1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i-1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i-1][j].rgbtBlue;

                gy.rgbtRed += -2 * image[i-1][j].rgbtRed;
                gy.rgbtGreen += -2 * image[i-1][j].rgbtGreen;
                gy.rgbtBlue += -2 * image[i-1][j].rgbtBlue;

                gx.rgbtRed += image[i-1][j+1].rgbtRed;
                gx.rgbtGreen += image[i-1][j+1].rgbtGreen;
                gx.rgbtBlue += image[i-1][j+1].rgbtBlue;

                gy.rgbtRed += -1 * image[i-1][j+1].rgbtRed;
                gy.rgbtGreen += -1 * image[i-1][j+1].rgbtGreen;
                gy.rgbtBlue += -1 * image[i-1][j+1].rgbtBlue;

                gx.rgbtRed += -2 * image[i][j-1].rgbtRed;
                gx.rgbtGreen += -2 * image[i][j-1].rgbtGreen;
                gx.rgbtBlue += -2 * image[i][j-1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j-1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j-1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j-1].rgbtBlue;

                gx.rgbtRed += 2 * image[i][j+1].rgbtRed;
                gx.rgbtGreen += 2 * image[i][j+1].rgbtGreen;
                gx.rgbtBlue += 2 * image[i][j+1].rgbtBlue;

                gy.rgbtRed += 0 * image[i][j+1].rgbtRed;
                gy.rgbtGreen += 0 * image[i][j+1].rgbtGreen;
                gy.rgbtBlue += 0 * image[i][j+1].rgbtBlue;

                gx.rgbtRed += -1 * image[i+1][j-1].rgbtRed;
                gx.rgbtGreen += -1 * image[i+1][j-1].rgbtGreen;
                gx.rgbtBlue += -1 * image[i+1][j-1].rgbtBlue;

                gy.rgbtRed += image[i+1][j-1].rgbtRed;
                gy.rgbtGreen += image[i+1][j-1].rgbtGreen;
                gy.rgbtBlue += image[i+1][j-1].rgbtBlue;

                gx.rgbtRed += 0 * image[i+1][j].rgbtRed;
                gx.rgbtGreen += 0 * image[i+1][j].rgbtGreen;
                gx.rgbtBlue += 0 * image[i+1][j].rgbtBlue;

                gy.rgbtRed += 2 * image[i+1][j].rgbtRed;
                gy.rgbtGreen += 2 * image[i+1][j].rgbtGreen;
                gy.rgbtBlue += 2 * image[i+1][j].rgbtBlue;

                gx.rgbtRed += image[i+1][j+1].rgbtRed;
                gx.rgbtGreen += image[i+1][j+1].rgbtGreen;
                gx.rgbtBlue += image[i+1][j+1].rgbtBlue;

                gy.rgbtRed += image[i+1][j+1].rgbtRed;
                gy.rgbtGreen += image[i+1][j+1].rgbtGreen;
                gy.rgbtBlue += image[i+1][j+1].rgbtBlue;
            }

            int redVal = (int)round(sqrt(gx.rgbtRed * gx.rgbtRed + gy.rgbtRed * gy.rgbtRed));
            int greenVal = (int)round(sqrt(gx.rgbtGreen * gx.rgbtGreen + gy.rgbtGreen * gy.rgbtGreen));
            int blueVal = (int)round(sqrt(gx.rgbtBlue * gx.rgbtBlue + gy.rgbtBlue * gy.rgbtBlue));

            if (redVal > 255) redVal = 255;
            if (greenVal > 255) greenVal = 255;
            if (blueVal > 255) blueVal = 255;

            image2[i][j].rgbtRed = redVal;
            image2[i][j].rgbtGreen = greenVal;
            image2[i][j].rgbtBlue = blueVal;
        }
    }

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            image[i][j].rgbtRed = image2[i][j].rgbtRed;
            image[i][j].rgbtGreen = image2[i][j].rgbtGreen;
            image[i][j].rgbtBlue = image2[i][j].rgbtBlue;
        }
    }
    return;
}

我的代码有很多行，因为它多次使用相同的操作（这是我设法解决问题的最简单方法）。

此外，if 语句中乘法的常量只是矩阵 gx 和 gy 的元素。我无缘无故地用 gx 和 gy 表示这些乘法的结果。我不想为这两个声明两个单独的矩阵，所以我对它们进行了硬编码。

我什至尝试手动验证自己，并使用 printf() 检查角落是否正确识别，一切都相应地工作。

问题是，当我使用 check50 时，这是我的输出：

此外，提供的名为 yard.bmp 的图像被转换为如下所示的“yardEdges.bmp”：

从我的角度来看，这是很多白色，我无法从这张照片中识别出任何边缘。

首先，请不要评判我的编码方式，我只是发现这是解决 'edges'.

的最简单（也是最长和最无聊）的方式

此外，我认为验证（代码中的这 9 个 if 语句）不会导致任何问题，也不会导致其中的内容（乘法等）。我亲手验证了所有这些，我很确定它们是正确的（虽然我可能是错的）。

我并不是要找人来验证这些陈述。我只是好奇我做错了什么，也许有人能看到我没有看到的东西。

谢谢！

Answer 1

您在计算中使用了错误的数据类型：

RGBTRIPLE gx, gy;

这种类型能够为每个通道保存 8 位值。当您为每个通道添加单独的组件时，您很容易在一个或多个通道中出现溢出。这会破坏您稍后将每个频道限制为 255 的尝试。

为避免这种情况，只需创建另一个结构：

struct {
  uint32_t rgbtRed;
  uint32_t rgbtGreen;
  uint32_t rgbtBlue;
} gx,gy;

这将允许相加而不会溢出。

CS50 滤镜 'Edge' returns 白色图像

CS50 Filter 'Edge' returns white image

c

filter

cs50

edge-detection

edx