Question

我想知道如何访问像素值和Floodfill 。在程序执行时，它会找到白色和黑色像素，但在应用floodfill函数时，最终结果是-all灰色图像。我想要做的是：

int best_resut = 0;
Point best = (0,0);

for(int i = 0; i < img_bin.rows; i++) 
{
    for(int j = 0; j < img_bin.cols; j++) 
    {  
        Vec3b intensity = img_bin.at<uchar>(i, j);
        uchar color = intensity.val[0];
        printf("Looking (%d,%d) Value %d\n", i, j, color);

        if(color==255)
        {
            printf("White Pixel\n");
            Point sp = (i, j);
            int current_result = floodFill(img_bin, sp, 128);

            if (current_result > best_result)
            {
                best_result = current_result;
                best = Point (i,j);
                floodFill(img_bin,sp, 255);
            }
            else
            {
                floodFill(img_bin, sp, 255);
            }
        }

    }

}

namedWindow("final",CV_WINDOW_AUTOSIZE);
imshow("final", img_bin);

Answer 1

假设您的图像是3通道彩色图像

    Vec3b intensity = img_bin.at<uchar>(i, j);

应该是

    Vec3b intensity = img_bin.at<Vec3b>(i, j);

由于Point接受（x，y）参数，它应该是Point sp = (j, i);，而不是Point sp = (i, j);

正确的代码：

int best_result = 0;
cv::Point best = (0,0);

cv::Vec3b white(255, 255, 255);

for(int i = 0; i < img_bin.rows; i++) 
{
    cv::Vec3b* img_row = img_bin.ptr<cv::Vec3b>(i);
    for(int j = 0; j < img_bin.cols; j++) 
    {  
        cv::Vec3b pixel = img_row[j];
        printf("Looking (%d,%d) Value %d %d %d\n", j, i, pixel[2], pixel[1], pixel[0]);

        if(pixel == white)
        {
            printf("White Pixel\n");
            cv::Point sp(j, i);
            int current_result = cv::floodFill(img_bin, sp, cv::Scalar(128, 128, 128));

            if (current_result > best_result)
            {
                best_result = current_result;
                best = sp;
            }
            cv::floodFill(img_bin, sp, cv::Scalar(255, 255, 255));
        }
    }
}

cv::namedWindow("final",CV_WINDOW_AUTOSIZE);
cv::imshow("final", img_bin);
cv::waitKey(0);

使用OpenCV2访问Mat中的像素

1 个答案: