边缘检测不起作用！二维像素数组中的最后一个下标未正确显示

Question

对于草率的代码或格式不正确的问题，我深表歉意，这是我的第一个 post！

此代码块的基本要点是使用 sobel 算子应用边缘检测。我有一个 for 循环嵌套在一个 for 循环中以迭代单个像素，另一个嵌套的 for 循环迭代一个较小的 2D 数组以应用 sobel 运算符，但最后一行像素和一些右边缘无法正确解析。非常感谢！

#include <math.h>
#include "helpers.h"

//prototype functions
void calcVert (int h, int w, int height, int width, RGBTRIPLE temp[height][width], int *blue, int *green, int *red);
void calcHori (int h, int w, int height, int width, RGBTRIPLE temp[height][width], int *blue, int *green, int *red);

// Detect edges
void edges(int height, int width, RGBTRIPLE image[height][width])
{
    int sobelBlueV;
    int sobelGreenV;
    int sobelRedV;
    int sobelBlueH;
    int sobelGreenH;
    int sobelRedH;
    RGBTRIPLE temp[height][width];
    for (int h = 0; h < height; h++)
    {
        for (int w = 0; w < width; w++)
        {
            temp[h][w].rgbtBlue = image[h][w].rgbtBlue;
            temp[h][w].rgbtGreen = image[h][w].rgbtGreen;
            temp[h][w].rgbtRed = image[h][w].rgbtRed;
        }
    }
    for (int h = 0; h < height; h++)
    {
        for (int w = 0; w < width; w++)
        {
            /*
            [-1] [0] [+1]    [+1] [+2] [+1]
            [-2] [0] [+2]    [0 ] [0 ] [0 ]
            [-1] [0] [+1]    [-1] [-2] [-1]
            
            */
            calcVert(h, w, height, width, temp, &sobelBlueV, &sobelGreenV, &sobelRedV);
            calcHori(h, w, height, width, temp, &sobelBlueH, &sobelGreenH, &sobelRedH);
            // ^2 and sqrt
            int bluePoint = round(sqrt(pow(sobelBlueV, 2) + pow(sobelBlueH, 2)));
            if (bluePoint > 255) bluePoint = 255;
            int GreenPoint = round(sqrt(pow(sobelGreenV, 2) + pow(sobelGreenH, 2)));
            if (GreenPoint > 255) GreenPoint = 255;
            int RedPoint = round(sqrt(pow(sobelRedV, 2) + pow(sobelRedH, 2)));
            if (RedPoint > 255) RedPoint = 255;
            image[h][w].rgbtBlue = bluePoint;
            image[h][w].rgbtGreen = GreenPoint;
            image[h][w].rgbtRed = RedPoint;
            
            
        }
    }
}
void calcVert (int h, int w, int height, int width, RGBTRIPLE temp[height][width], int *blue, int *green, int *red)
{
            //row 1: [-1] [0] [+1]
            //row 2: [-2] [0] [+2]
            //row 3: [-1] [0] [+1] vertical kernel
    int cellCalc = 0;
    int totalRed = 0;
    int totalBlue = 0;
    int totalGreen = 0;
    //row 1
    for (int relativeH = -1; relativeH <= 1; relativeH++)
    {
        for (int relativeW = -1; relativeW <= 1; relativeW++)
        {
            //overreach cases
            if (h + relativeH < 0 && w + relativeW < 0)//top left corner
            {
                //set cell values
                if (relativeH == 0 && relativeW == -1) cellCalc = 0;
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 0;
                if (relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 1 && relativeW == 1) cellCalc = 1;
                if (relativeH == 0 && relativeW ==1) cellCalc = 2;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (h + relativeH < 0 && w + relativeW >= width)//top right corner
            {
                //set cell values
                if (relativeH == 0 && relativeW == -1) cellCalc = -2;
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = -1;
                if (relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 0 && relativeW ==1) cellCalc = 0;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (h + relativeH < 0)//top edge
            {
                //set cell values
                if (relativeH == 0 && relativeW == -1) cellCalc = -2;
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = -1;
                if (relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 1 && relativeW == 1) cellCalc = 1;
                if (relativeH == 0 && relativeW ==1) cellCalc = 2;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (w + relativeW < 0 && h + relativeH >= height)//bottom left corner
            {
                //set cell values
                if (relativeH == 0 && relativeW == -1) cellCalc = 0;
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 0;
                if (relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 1;
                if (relativeH == 1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 0 && relativeW ==1) cellCalc = 2;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (w + relativeW < 0)//left edge
            {
                //set cell values
                if (relativeH == 0 && relativeW == -1) cellCalc = 0;
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 0;
                if (relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 1;
                if (relativeH == 1 && relativeW == 1) cellCalc = 1;
                if (relativeH == 0 && relativeW ==1) cellCalc = 2;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (h + relativeH >= height && w + relativeW >= width)//bottom right corner
            {
                //set cell values
                if (relativeH == 0 && relativeW == -1) cellCalc = -2;
                if (relativeH == -1 && relativeW == -1) cellCalc = -1;
                if (relativeH == 1 && relativeW == -1) cellCalc = 0;
                if (relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 0 && relativeW ==1) cellCalc = 0;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (w + relativeW >= width)//right edge
            {
                //set cell values
                if (relativeH == 0 && relativeW == -1) cellCalc = -2;
                if (relativeH == -1 && relativeW == -1) cellCalc = -1;
                if (relativeH == 1 && relativeW == -1) cellCalc = -1;
                if (relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 0 && relativeW ==1) cellCalc = 0;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else //valid cases
            {
                //set cell values
                if (relativeH == 0 && relativeW == -1) cellCalc = -2;
                if (relativeH == -1 && relativeW == -1) cellCalc = -1;
                if (relativeH == 1 && relativeW == -1) cellCalc = -1;
                if (relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 1;
                if (relativeH == 1 && relativeW == 1) cellCalc = 1;
                if (relativeH == 0 && relativeW ==1) cellCalc = 2;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
        }
    }
}

void calcHori (int h, int w, int height, int width, RGBTRIPLE temp[height][width], int *blue, int *green, int *red)
{
            //row 1: [+1] [+2] [+1]
            //row 2: [ 0] [ 0] [ 0]
            //row 3: [-1] [-2] [-1]
    int cellCalc = 0;
    int totalRed = 0;
    int totalBlue = 0;
    int totalGreen = 0;
    //row 1
    for (int relativeH = -1; relativeH <= 1; relativeH++)
    {
        for (int relativeW = -1; relativeW <= 1; relativeW++)
        {
            //overreach cases
            if (h + relativeH < 0 && w + relativeW < 0)//top left corner
            {
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == -1 && relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 0;
                if (relativeH == 1 && relativeW == 0) cellCalc = 2;
                if (relativeH == 1 && relativeW == 1) cellCalc = 1;
            }
            else if (h + relativeH < 0 && w + relativeW >= width)//top right corner
            {
                //set cell values
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == -1 && relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 1;
                if (relativeH == 1 && relativeW == 0) cellCalc = 2;
                if (relativeH == 1 && relativeW == 1) cellCalc = 0;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (h + relativeH < 0)//top edge
            {
                //set cell values
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == -1 && relativeW == 0) cellCalc = 0;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 1;
                if (relativeH == 1 && relativeW == 0) cellCalc = 2;
                if (relativeH == 1 && relativeW == 1) cellCalc = 1;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (w + relativeW < 0 && h + relativeH >= height)//bottom left corner
            {
                //set cell values
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == -1 && relativeW == 0) cellCalc = -2;
                if (relativeH == -1 && relativeW == 1) cellCalc = -1;
                if (relativeH == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 0;
                if (relativeH == 1 && relativeW == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == 1) cellCalc = 0;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (w + relativeW < 0)//left edge
            {
                //set cell values
                if (relativeH == -1 && relativeW == -1) cellCalc = 0;
                if (relativeH == -1 && relativeW == 0) cellCalc = -2;
                if (relativeH == -1 && relativeW == 1) cellCalc = -1;
                if (relativeH == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 0;
                if (relativeH == 1 && relativeW == 0) cellCalc = 2;
                if (relativeH == 1 && relativeW == 1) cellCalc = 1;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (h + relativeH >= height && w + relativeW >= width)//bottom right corner
            {
                //set cell values
                if (relativeH == -1 && relativeW == -1) cellCalc = -1;
                if (relativeH == -1 && relativeW == 0) cellCalc = -2;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 0;
                if (relativeH == 1 && relativeW == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == 1) cellCalc = 0;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else if (w + relativeW >= width)//right edge
            {
                //set cell values
                if (relativeH == -1 && relativeW == -1) cellCalc = -1;
                if (relativeH == -1 && relativeW == 0) cellCalc = -2;
                if (relativeH == -1 && relativeW == 1) cellCalc = 0;
                if (relativeH == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 1;
                if (relativeH == 1 && relativeW == 0) cellCalc = 2;
                if (relativeH == 1 && relativeW == 1) cellCalc = 0;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
            else //valid cases
            {
                //set cell values
                if (relativeH == -1 && relativeW == -1) cellCalc = -1;
                if (relativeH == -1 && relativeW == 0) cellCalc = -2;
                if (relativeH == -1 && relativeW == 1) cellCalc = -1;
                if (relativeH == 0) cellCalc = 0;
                if (relativeH == 1 && relativeW == -1) cellCalc = 1;
                if (relativeH == 1 && relativeW == 0) cellCalc = 2;
                if (relativeH == 1 && relativeW == 1) cellCalc = 1;
                
                totalBlue += ((temp[h + relativeH][w + relativeW].rgbtBlue) * cellCalc);
                totalGreen += ((temp[h + relativeH][w + relativeW].rgbtGreen) * cellCalc);
                totalRed += ((temp[h + relativeH][w + relativeW].rgbtRed) * cellCalc);
                
                *blue = totalBlue;
                *green = totalGreen;
                *red = totalRed;
            }
        }
    }
}

Answer 1

您的代码确实很复杂，并且由于每个像素的测试数量，效率很低。我强烈建议您使用以下结构重写该函数：

处理第一行；
处理内部行的循环；
处理最后一行；

并且对于每一行

处理第一个像素；
处理内列循环；
处理最后一个像素。

对于内核的应用，不要使用双循环而是hard-code公式（实际上有六项，而不是九项）。将处理拆分为九个实例可以让您干净地专门化边界上的代码。

为了避免 RGB 组件的重复，您可以使用辅助函数，希望它们能被编译器内联。

边缘检测不起作用！二维像素数组中的最后一个下标未正确显示

edge detection not working! last subscript in 2D array of pixels isnt coming out properly

c

image-processing

sobel

cs50