CS50模糊功能不能通过check50，即使图像正在模糊。

Question

我正在处理一个CS50问题集，我需要在其中做一个 盒状模糊 为图像的每一个像素创建一个if语句。虽然我的代码有点多余，因为我为像素的特殊情况（如边缘和角落）创建了8个if语句，但它像预期的那样模糊了图像，所以我真的不知道如何解决这个问题。这是错误代码。

:( blur correctly filters middle pixel
    expected "127 140 149\n", not "145 160 169\n"
:( blur correctly filters pixel on edge
    expected "80 95 105\n", not "90 106 116\n"
:) blur correctly filters pixel in corner
:( blur correctly filters 3x3 image
    expected "70 85 95\n80 9...", not "70 85 95\n90 1..."
:( blur correctly filters 4x4 image
    expected "70 85 95\n80 9...", not "70 85 95\n90 1..."

还有一个更详细的错误代码 此处 (只看 "模糊 "错误)

下面是我的代码。

// Blur image
void blur(int height, int width, RGBTRIPLE image[height][width])
{
    int blue;
    int green;
    int red;
    int counter = 0;

    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < width; j++)
        {
            if (i == 0 && j == 0)
            {
                // top left corner
                blue = (image[i][j].rgbtBlue + image[i + 1][j].rgbtBlue + image[i][j+1].rgbtBlue + image[i + 1][j+1].rgbtBlue);
                green = (image[i][j].rgbtGreen + image[i + 1][j].rgbtGreen + image[i][j+1].rgbtGreen + image[i + 1][j+1].rgbtGreen);
                red = (image[i][j].rgbtRed + image[i + 1][j].rgbtRed + image[i][j+1].rgbtRed + image[i + 1][j+1].rgbtRed);
                counter = 4;
            }

            else if (i == 0 && j == (width - 1))
            {
                // top right corner
                blue = (image[i][j].rgbtBlue + image[i + 1][j].rgbtBlue + image[i][j-1].rgbtBlue + image[i + 1][j-1].rgbtBlue);
                green = (image[i][j].rgbtGreen + image[i + 1][j].rgbtGreen + image[i][j-1].rgbtGreen + image[i + 1][j-1].rgbtGreen);
                red = (image[i][j].rgbtRed + image[i + 1][j].rgbtRed + image[i][j-1].rgbtRed + image[i + 1][j-1].rgbtRed);
                counter = 4;
            }

            else if (i == 0 && (j != 0 || j != (width - 1)))
            {
                // top edge
                blue = (image[i][j - 1].rgbtBlue + image[i][j].rgbtBlue + image[i][j + 1].rgbtBlue + image[i + 1][j].rgbtBlue + image[i+1][j - 1].rgbtBlue + image[i + 1][j + 1].rgbtBlue);
                green = (image[i][j - 1].rgbtGreen + image[i][j].rgbtGreen + image[i][j + 1].rgbtGreen + image[i + 1][j].rgbtGreen + image[i+1][j - 1].rgbtGreen + image[i + 1][j + 1].rgbtGreen);
                red = (image[i][j - 1].rgbtRed + image[i][j].rgbtRed + image[i][j + 1].rgbtRed + image[i + 1][j].rgbtRed + image[i+1][j - 1].rgbtRed + image[i + 1][j + 1].rgbtRed);
                counter = 6;
            }

            else if (i == (height - 1) && j == 0)
            {
                // bottom left corner
                blue = (image[i-1][j + 1].rgbtBlue + image[i][j + 1].rgbtBlue + image[i - 1][j].rgbtBlue + image[i][j].rgbtBlue);
                green = (image[i-1][j + 1].rgbtGreen + image[i][j + 1].rgbtGreen + image[i - 1][j].rgbtGreen + image[i][j].rgbtGreen);
                red = (image[i-1][j + 1].rgbtRed + image[i][j + 1].rgbtRed + image[i - 1][j].rgbtRed + image[i][j].rgbtRed);
                counter = 4;
            }

            else if (i == (height - 1) && j == (width - 1))
            {
                // bottom right corner
                blue = (image[i][j].rgbtBlue + image[i - 1][j].rgbtBlue + image[i][j-1].rgbtBlue + image[i - 1][j-1].rgbtBlue);
                green = (image[i][j].rgbtGreen + image[i - 1][j].rgbtGreen + image[i][j-1].rgbtGreen + image[i - 1][j-1].rgbtGreen);
                red = (image[i][j].rgbtRed + image[i - 1][j].rgbtRed + image[i][j-1].rgbtRed + image[i - 1][j-1].rgbtRed);
                counter = 4;
            }

            else if (i == (height - 1) && (j != 0 || j != (width - 1)))
            {
                // bottom edge
                blue = (image[i][j].rgbtBlue + image[i][j - 1].rgbtBlue + image[i][j + 1].rgbtBlue + image[i - 1][j].rgbtBlue + image[i-1][j - 1].rgbtBlue + image[i - 1][j + 1].rgbtBlue);
                green = (image[i][j].rgbtGreen + image[i][j - 1].rgbtGreen + image[i][j + 1].rgbtGreen + image[i - 1][j].rgbtGreen + image[i-1][j - 1].rgbtGreen + image[i - 1][j + 1].rgbtGreen);
                red = (image[i][j].rgbtRed + image[i][j - 1].rgbtRed + image[i][j + 1].rgbtRed + image[i - 1][j].rgbtRed + image[i-1][j - 1].rgbtRed + image[i - 1][j + 1].rgbtRed);
                counter = 6;
            }

            else if (j == 0 && (i != 0 || i != (height - 1)))
            {
                // left edge
                blue = (image[i][j].rgbtBlue + image[i - 1][j].rgbtBlue + image[i+1][j].rgbtBlue + image[i][j + 1].rgbtBlue + image[i-1][j + 1].rgbtBlue + image[i + 1][j + 1].rgbtBlue);
                green = (image[i][j].rgbtGreen + image[i - 1][j].rgbtGreen + image[i+1][j].rgbtGreen + image[i][j + 1].rgbtGreen + image[i-1][j + 1].rgbtGreen + image[i + 1][j + 1].rgbtGreen);
                red = (image[i][j].rgbtRed + image[i - 1][j].rgbtRed + image[i+1][j].rgbtRed + image[i][j + 1].rgbtRed + image[i-1][j + 1].rgbtRed + image[i + 1][j + 1].rgbtRed);
                counter = 6;
            }

            else if (j == (width - 1) && (i != 0 || i != (height - 1)))
            {
                // right edge
                blue = (image[i][j].rgbtBlue + image[i-1][j].rgbtBlue + image[i + 1][j].rgbtBlue + image[i][j - 1].rgbtBlue + image[i + 1][j-1].rgbtBlue + image[i-1][j - 1].rgbtBlue);
                green = (image[i][j].rgbtGreen + image[i-1][j].rgbtGreen + image[i + 1][j].rgbtGreen + image[i][j - 1].rgbtGreen + image[i + 1][j-1].rgbtGreen + image[i-1][j - 1].rgbtGreen);
                red = (image[i][j].rgbtRed + image[i-1][j].rgbtRed + image[i + 1][j].rgbtRed + image[i][j - 1].rgbtRed + image[i + 1][j-1].rgbtRed + image[i-1][j - 1].rgbtRed);
                counter = 6;
            }

            else
            {
                blue = (image[i][j].rgbtBlue + image[i - 1][j].rgbtBlue + image[i + 1][j].rgbtBlue + image[i][j - 1].rgbtBlue + image[i][j + 1].rgbtBlue + image[i - 1][j + 1].rgbtBlue + image[i-1][j - 1].rgbtBlue + image[i + 1][j - 1].rgbtBlue + image[i + 1][j + 1].rgbtBlue);
                green = (image[i][j].rgbtGreen + image[i - 1][j].rgbtGreen + image[i + 1][j].rgbtGreen + image[i][j - 1].rgbtGreen + image[i][j + 1].rgbtGreen + image[i - 1][j + 1].rgbtGreen + image[i-1][j - 1].rgbtGreen + image[i + 1][j - 1].rgbtGreen + image[i + 1][j + 1].rgbtGreen);
                red = (image[i][j].rgbtRed + image[i - 1][j].rgbtRed + image[i + 1][j].rgbtRed + image[i][j - 1].rgbtRed + image[i][j + 1].rgbtRed + image[i - 1][j + 1].rgbtRed + image[i-1][j - 1].rgbtRed + image[i + 1][j - 1].rgbtRed + image[i + 1][j + 1].rgbtRed);
                counter = 9;
            }

            image[i][j].rgbtBlue = round((float) blue / counter);
            image[i][j].rgbtGreen = round((float) green / counter);
            image[i][j].rgbtRed = round((float) red / counter);
        }
    }
    return;
}

看了其他人对这个问题的回答，我看到有些人做了第二个嵌套的 for 循环来存储像素的原始值。我最初想实现这个功能，但最后还是出现了问题，所以我觉得没有必要。这是否是我的代码的问题，如果是，我将如何在我的代码中正确实现 "原始值 "像素？如果不是，有谁知道问题所在？先谢谢你了。

Answer 1

你正在修改你的 image 当您对像素应用模糊功能时，就会产生模糊值。这意味着当您修改少数像素时，相邻像素的模糊值将以 "模糊像素值 "计算。这是不对的。所有的计算必须在原始图像像素值内完成。为此，您应该创建一个 image 起初 temp)，并在该范围内进行所有这些计算。temp 的图像，其中有未修改的像素值。

将此添加到你的代码的开头。

RGBTRIPLE temp[height][width]; // create a temporary array to store a duplicate of image.

// save a new copy of image as temp per color.
for (int i = 0; i < height; i++) //Loop for height of image.
{
    for (int j = 0; j < width; j++) //Loop for width of image and save color values in temp.
    {
        temp[i][j] = image[i][j];
    }
}

替换成 image 与 temp 在你的计算中（除了最后的作业）。