Question

我有一个问题，理论上很容易，但......理论上......我想将Mat帧图像转换为灰度。我知道我应该使用这样的东西：

cv :: cvtColor（frameA1，grayImageA1，CV_BGR2GRAY）;

但结果如下：

http://i57.tinypic.com/jfvodt.jpg

我不知道为什么在转换为灰度后我有3张图像。这是我的代码的一部分：

  private: System::Void backgroundWorker1_DoWork(System::Object^  sender, System::ComponentModel::DoWorkEventArgs^  e) {
    BackgroundWorker^ worker = dynamic_cast<BackgroundWorker^>(sender);
    capture1.open(1);
    while (camStatus1){
        if (camBusy1) continue;
        capture1.read(frameA1);
        if (frameA1.empty()) continue;
        cv::cvtColor(frameA1, grayImageA1, CV_BGR2GRAY);
        worker->ReportProgress(1);
    }

}
private: System::Void backgroundWorker1_ProgressChanged(System::Object^  sender, System::ComponentModel::ProgressChangedEventArgs^  e) {
    if (!camBusy1){
        camBusy1 = 1;
        System::Drawing::Graphics^ graphics = imageBox1->CreateGraphics();
        System::IntPtr ptr(frameA1.ptr());
        System::Drawing::Bitmap^ b = gcnew System::Drawing::Bitmap(frameA1.cols, frameA1.rows, frameA1.step, System::Drawing::Imaging::PixelFormat::Format24bppRgb, ptr);
        System::Drawing::RectangleF rect(0, 0, imageBox1->Width, imageBox1->Height);
        graphics->DrawImage(b, rect);
        if (debugA){
            System::Drawing::Graphics^ graphics = imageBox3->CreateGraphics();
            System::IntPtr ptr(grayImageA1.ptr());
            System::Drawing::Bitmap^ b = gcnew System::Drawing::Bitmap(grayImageA1.cols, grayImageA1.rows, grayImageA1.step, System::Drawing::Imaging::PixelFormat::Format24bppRgb, ptr);
            System::Drawing::RectangleF rect(0, 0, imageBox3->Width, imageBox3->Height);
            graphics->DrawImage(b, rect);
        }
        camBusy1 = 0;
    }
}

为什么它的工作方式如此？我希望你能帮我解决这个理论上容易的问题：）

Answer 1

我打赌，你的cvtColor（）调用工作正常（尝试imwrite（）输出，看看你自己），但是然后：

您尝试使用24位像素标记对8位图像进行blit：

System::Drawing::Bitmap^ b = gcnew System::Drawing::Bitmap(grayImageA1.cols, grayImageA1.rows, grayImageA1.step, System::Drawing::Imaging::PixelFormat::Format24bppRgb, ptr);

如果您想保留像素标记，则必须再次转换为3个频道：

Mat grayImage24;
cv::cvtColor(grayImageA1, grayImage24, CV_GRAY2BGR);
System::Drawing::Bitmap^ b = gcnew System::Drawing::Bitmap(grayImage24.cols, grayImage24.rows, grayImage24.step, System::Drawing::Imaging::PixelFormat::Format24bppRgb, ptr);

（现在不能试试，但是iirc，没有办法用winforms blit 8bit图像）

OpenCV表单应用程序 - 将Mat转换为灰度

1 个答案: