OpenCV實現將任意形狀ROI區域置黑

比較常用的是將 Rect 矩形區域置黑，代碼如下：

int testMaskRectROI() {
    cv::Mat image = cv::imread("./test_img/detect_pic.jpeg");

    cv::Rect rect_mask(57, 93, 92, 92);
    cv::Mat subImage = image(rect_mask);
    subImage.setTo(0);

    cv::imshow("src", image);
    cv::waitKey(0);
}

效果如下：

但在做人臉檢測的旋轉追蹤時，矩形框是隨角度旋轉的，那如何處理呢？直接上代碼：

int testMaskAnyROI() {
    cv::Mat image = cv::imread("./test_img/detect_pic.jpeg");

    vector<cv::Point> contour;
    contour.push_back(cv::Point(66, 80));
    contour.push_back(cv::Point(38, 177));
    contour.push_back(cv::Point(134, 205));
    contour.push_back(cv::Point(162, 108));

    vector<vector<cv::Point> > contours;
    contours.push_back(contour);
    cv::drawContours(image, contours, -1, cv::Scalar::all(0), CV_FILLED);

    cv::imshow("src", image);
    cv::waitKey(0);
}

效果如下：