用C++和OpenCV查找最左边、最右边、最高、最蓝的像素 我试图用C++和OpenCV编写代码，识别哪一个蓝色像素从左、右、上、下都是第一个。 我正在使用的图片是：

我想收到的是这样一张照片：

这是我的代码，直到现在，我真的不明白为什么它不工作

    void findBluePixels(Mat& original, Point2f min_x, Point2f max_x, Point2f min_y, Point2f max_y) {
    //First I set every point to the beginning of the image
        min_x = Point(0, 0);
        max_x = Point(0, 0);
        min_y = Point(0, 0);
        max_y = Point(0, 0);
    //looking for the most left blue pixel (the blue pixel with the smallest x value)
    //we are going through every column and every row
        for (int col = 0; col < original.cols; col++) {
            for (int row = 0; row < original.rows; row++) {
    //we check for every pixel if the pixel is blue and if the column of the pixel is bigger or equal to the beginning of the image
    if (original.at<Vec3b>(row, col)[0] == 255 && 
    original.at<Vec3b>(row, col)[1] == 0 &&
 original.at<Vec3b>(row, col)[2] == 0 && col >= min_x.y) {
    //if yes we have new value for the min_x and we stop looking because we have found the most left blue pixel
        min_x = Point(row, col);
        break;
                }
            }
        }
    //looking for the most right blue pixel (the blue pixel with the biggest x value)
    //we are going through every column and every row
        for (int col = 0; col < original.cols; col++) {
            for (int row = 0; row < original.rows; row++) {
    //we check for every pixel if the pixel is blue and if the column of the pixel is bigger or equal to the beginning of the image
    if (original.at<Vec3b>(row, col)[0] == 255 && 
    original.at<Vec3b>(row, col)[1] == 0 && 
original.at<Vec3b>(row, col)[2] == 0 && col >= max_x.y) {
    //if yes we have new value for the max_x, but we don't break because we are looking for the biggest blue pixel
    //we continue to search until the end of the picture
    max_x = Point(row, col);
                }
            }
        }
    //looking for the highest blue pixel (the blue pixel with the smallest y value)
    //we are going through every row and every column
        for (int row = 0; row < original.rows; row++) {
            for (int col = 0; col < original.cols; col++) {
    //we check for every pixel if the pixel is blue and if the row of the pixel is bigger or equal to the beginning of the image
    if (original.at<Vec3b>(row, col)[0] == 255 && 
    original.at<Vec3b>(row, col)[1] == 0 &&
    original.at<Vec3b>(row, col)[2] == 0 && row >= min_y.x) {
    //if yes we have new value for the min_y and we stop looking because we have found the highest blue pixel
    min_y = Point(row, col);
    break;
                }
            }
        }
    //looking for the most down blue pixel (the blue pixel with the biggest y value)
    //we are going through every column and every row
        for (int row = 0; row < original.rows; row++) {
            for (int col = 0; col < original.cols; col++) {
    //we check for every pixel if the pixel is blue and if the row of the pixel is bigger or equal to the beginning of the image
    if (original.at<Vec3b>(row, col)[0] == 255 && 
    original.at<Vec3b>(row, col)[1] == 0 &&
    original.at<Vec3b>(row, col)[2] == 0 && row >= max_y.x) {
    //if yes we have new value for the max_y, but we don't break because we are looking for the biggest blue pixel
    //we continue to search until the end of the picture
    max_y = Point(row, col);
                }
            }
        }
    //Here I want to make green points on the pixels we have found
    circle(original, min_x, 3, Scalar(0, 255, 0), 8, LINE_AA);
    circle(original, max_x, 3, Scalar(0, 255, 0), 8, LINE_AA);
    circle(original, min_y, 3, Scalar(0, 255, 0), 8, LINE_AA);
    circle(original, max_y, 3, Scalar(0, 255, 0), 8, LINE_AA);
}

我最后收到的点完全是随机的

如果有人能帮忙，我会非常感激的！：

您只能在矩阵上循环一次，并在同一内部for循环体中执行所有检查

喜欢使用名字而不是数字。e、 g.如果是original.atrow，则列[BLUE]==255，而不是如果是original.atrow，则列[0]==255

请仔细检查像素中的索引0是否确实包含蓝色值，不是RGB吗

逻辑问题：如果你想找到例如最小x，你应该编码col 如果,col 和init如下所示：

min_x = Point(MAX_COL, 0);
max_x = Point(MIN_COL, 0);
min_y = Point(0, MAX_ROW);
max_y = Point(0, MIN_ROW);

---

正如@nivpeled提到的，但是在代码中

void findBluePixels(Mat& original) {
    Point min_x = Point(original.cols, original.rows);
    Point min_y = Point(original.cols, original.rows);
    Point max_x = Point(-1, -1);
    Point max_y = Point(-1, -1);
    //looking for the most left blue pixel (the blue pixel with the smallest x value)
    //we are going through every column and every row

    const Vec3b blueColor(255, 0, 0);
    for (int row = 0; row < original.rows; row++) {
        for (int col = 0; col < original.cols; col++) {
            if (blueColor != original.at<Vec3b>(row, col))
                continue;

            if (min_x.x > col) {
                min_x = Point(col, row);
            }
            if (max_x.x < col) {
                max_x = Point(col, row);
            }

            if (min_y.y > row) {
                min_y = Point(col, row);
            }
            if (max_y.y < row) {
                max_y = Point(col, row);
            }
        }
    }
    //Here I want to make green points on the pixels we have found
    circle(original, min_x, 13, Scalar(0, 255, 0), 8, LINE_AA);
    circle(original, max_x, 13, Scalar(0, 255, 0), 8, LINE_AA);
    circle(original, min_y, 13, Scalar(0, 255, 0), 8, LINE_AA);
    circle(original, max_y, 13, Scalar(0, 255, 0), 8, LINE_AA);
}

---

不知道，但是你应该提取一个函数bool is_blue const Pixel&使代码更可读和简洁。对不起，我觉得你的逻辑完全是随机的。不管怎么说，这就是调试器的作用，使用调试器可以准确地找到程序偏离预期的时间和地点。您没有在帖子中指定坐标系，这使得很难确定。但是Cal>＝Max x.y比较一个列，我认为它是一个x坐标，带有y坐标。那没有意义。与所有其他比较一样，您似乎混淆了x和y。您的符号有问题。。如果x从左到右，y从上到下或相反，w/e、col对应于x值，而row对应于y值。如果这不是您想要的符号，则最左边和最右边的定义是错误的。您的min_x和max_x代码是相同的。一团糟>=非常感谢您提供的解决方案和提示！我会使蓝色成为常量，甚至是静态常量。

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