java - 我在与输入颜色 channel 相关的 inRange 函数上遇到错误

Question

我一直在尝试将 inRange 函数应用于我的图像。在没有 InRange 的情况下，到 HSV 的转换工作正常，但是当我尝试应用它时，我可以获得我想要的颜色(在本例中为紫色)。我收到错误。

我正在使用OpenCV 4.0.3

    Mat plate_img = imread(imagePath, IMREAD_COLOR);
    Mat plate_gradient = new Mat();
    GaussianBlur(plate_img, plate_img,new Size(7,7),0);

    Mat boosted_plate_gradient =  new Mat(plate_img.rows(), plate_img.cols(), CvType.CV_8U, new Scalar(3));

    morphologyEx(plate_img, plate_gradient, MORPH_GRADIENT, new Mat());
    plate_gradient.convertTo(plate_gradient, -1, 9.5, -70);
    cvtColor(plate_gradient,plate_gradient, COLOR_BGR2HSV);

    Scalar low = new Scalar(151,48.6,85.5);
    Scalar high = new Scalar(150,100,50.2);

    Core.inRange(plate_gradient, low, high, boosted_plate_gradient);

E/cv::error(): OpenCV(4.0.1) Error: Unspecified error (> Invalid number of channels in input image:
    >     'VScn::contains(scn)'
    > where
    >     'scn' is 1
    ) in cv::CvtHelper<VScn, VDcn, VDepth, sizePolicy>::CvtHelper(cv::InputArray, cv::OutputArray, int) [with VScn = cv::Set<3, 4>; VDcn = cv::Set<1>; VDepth = cv::Set<0, 2, 5>; cv::SizePolicy sizePolicy = (cv::SizePolicy)2u; cv::InputArray = const cv::_InputArray&; cv::OutputArray = const cv::_OutputArray&], file ...\opencv\sources\modules\imgproc\src\color.hpp, line 259


E/org.opencv.imgproc: imgproc::cvtColor_11() caught cv::Exception: OpenCV(4.0.1) ...\opencv\sources\modules\imgproc\src\color.hpp:259: error: (-2:Unspecified error) in function 'cv::CvtHelper<VScn, VDcn, VDepth, sizePolicy>::CvtHelper(cv::InputArray, cv::OutputArray, int) [with VScn = cv::Set<3, 4>; VDcn = cv::Set<1>; VDepth = cv::Set<0, 2, 5>; cv::SizePolicy sizePolicy = (cv::SizePolicy)2u; cv::InputArray = const cv::_InputArray&; cv::OutputArray = const cv::_OutputArray&]'
    > Invalid number of channels in input image:
    >     'VScn::contains(scn)'
    > where
    >     'scn' is 1

Answer 1

显然，我的另一个cvtcolor(在BGR2HSV之后)是在我尝试从BGR2GRAY转换它时抛出错误的，尽管当我没有实现inRange函数时它确实起作用