OpenCV 网络摄像头提要未在 PictureBox Visual Studio 2015 中显示答案

【问题标题】：OpenCV Webcam feed not displaying in PictureBox visual studio 2015OpenCV 网络摄像头提要未在 PictureBox Visual Studio 2015 中显示
【发布时间】：2017-07-08 21:53:50
【问题描述】：

嗨，所以我使用 opencv 从我的默认摄像头获取网络摄像头提要，我希望在我的 Windows 窗体上的图片框中显示它。我的网络摄像头打开了，但由于某种原因，提要从未显示在我的图片框上。请有人帮忙指出/解决问题，因为我现在被困在这里。提前致谢。

在 myform.h 中，我有此代码将图片框发送到 myform.cpp 文件：

System::Windows::Forms::PictureBox^ mypicbox1(void)  
{
    opencv_gui::MyForm aform;
    return aform.pictureBox1;
}

获取videofeed并放入myform.cpp中我的图片框的代码是：

void opencv_gui::DrawCvImage(const cv::Mat& cvImage)
{
    System::Windows::Forms::PictureBox^ pictureBox = mypicbox1();
    // only color images are supported
    assert(cvImage.type() == CV_8UC3);

    if ((pictureBox->Image == nullptr) || (pictureBox->Width != cvImage.cols) || (pictureBox->Height != cvImage.rows))
    {
        pictureBox->Width = cvImage.cols;
        pictureBox->Height = cvImage.rows;
        pictureBox->Image = gcnew System::Drawing::Bitmap(cvImage.cols, cvImage.rows);
    }

    // Create System::Drawing::Bitmap from cv::Mat
    System::Drawing::Bitmap^ bmpImage = gcnew System::Drawing::Bitmap(
        cvImage.cols, cvImage.rows, cvImage.step,
        System::Drawing::Imaging::PixelFormat::Format24bppRgb,
        System::IntPtr(cvImage.data)
    );

    // Draw Bitmap over a PictureBox
    System::Drawing::Graphics^ g = System::Drawing::Graphics::FromImage(pictureBox->Image);

    g->DrawImage(bmpImage, 0, 0, cvImage.cols, cvImage.rows);
    pictureBox->Refresh();

    delete g;
}


//camera feed
int opencv_gui::video_cap(void)
{
    VideoCapture cap;

    if (!cap.open(0)) // open the default camera (camera 0), use something different from 0 otherwise;
        return 0;
    for (;;)
    {
        Mat frame;
        cap >> frame;
        if (frame.empty()) break; // end of video stream
        DrawCvImage(frame);
        if (waitKey(10) == 27) break; // stop capturing by pressing ESC 
    }
    // the camera will be closed automatically upon exit
    // cap.close();
    return 0;
}

这是我的调试日志：我使用了“>>>>>>>>”之类的箭头来显示重要参数，并使用“RED >>>>>>”来显示错误参数。

cvImage { flags=1124024336 dims=2 rows=480 ...} cv::Mat&
分配器 0x0000000000000000 cv::MatAllocator*

cols 640 整数
数据 0x0000026AC2146F80 无符号字符* *(*cvImage).data 0 '' 无符号字符
dataend 0x0000026AC2227F80 unsigned char*
datalimit 0x0000026AC2227F80 unsigned char*
datastart 0x0000026AC2146F80 无符号字符* 调暗 2 int 标志 1124024336 int 第 480 行 int
尺寸 { p=0x000000DBDFF0DE80 } cv::MatSize
p 0x000000DBDFF0DE80 整数* *(*cvImage).size.p 0 int
步骤 { p=0x000000DBDFF0DEC8 buf={Length=2} } cv::MatStep
buf {Length=2} 无符号 __int64[]
p 0x000000DBDFF0DEC8 无符号 __int64*
u 0x0000026AA4814780 cv::UMatData*
RED >>>>> bmpImage 0x0000026aa62a1fd0 { defaultTransparentColor= } System::Drawing::Bitmap^
RED >>>>>> System::Drawing::Image^ 0x0000026aa62a1fd0 { nativeImage=2657511292512 rawData= userData= } System::Drawing::Image^ defaultTransparentColor System::Drawing::Color g 系统::绘图::图形^
RED >>>>>> pictureBox 0x0000026aa62a1388 {borderStyle=System::Windows::Forms::BorderStyle::None image=0x0000026aa62a1fa0 sizeMode=System::Windows::Forms::PictureBoxSizeMode::Normal ... } System::Windows::Forms::PictureBox^
RED >>>>>> System::Windows::Forms::Control^ 0x0000026aa62a1388 { ControlKeyboardRouting= PaletteTracing= FocusTracing= ...} System::Windows::Forms::Control^ AllowDrop false bool BorderStyle System::Windows::Forms::BorderStyle::None System::Windows::Forms::BorderStyle CausesValidation true bool
CreateParams 0x0000026aa62a15d8 { className= caption= style=1442840576 ...} System::Windows::Forms::CreateParams^ DefaultImeMode System::Windows::Forms::ImeMode::Disable System::Windows::Forms::ImeMode
DefaultSize {Width=100 Height=50} System::Drawing::Size EVENT_SIZEMODECHANGED 0x0000026aa629af50 System::Object^
ErrorImage 0x0000026aa629b110 { nativeImage=2657511192608 rawData= userData= } System::Drawing::Image^
字体 0x0000026aa6280148 {} System::Drawing::Font^
前景色 {RGB=0x0} System::Drawing::Color
图像 0x0000026aa62a1fa0 { nativeImage=2657511290992 rawData= userData= } System::Drawing::Image^
[System::Drawing::Bitmap^] 0x0000026aa62a1fa0 { defaultTransparentColor= } System::Drawing::Bitmap^
System::MarshalByRefObject^ 0x0000026aa62a1fa0 { __identity= } System::MarshalByRefObject^ 标志 2 int
FrameDimensionsList {Length=1} 数组 ^ 身高 480 英寸 HorizontalResolution 96.000000 浮点数
调色板 0x0000026aa62a25e8 { flags=1129621568 entries={Length=0} } System::Drawing::Imaging::ColorPalette^
PhysicalDimension { width=640.00000 height=480.00000 } System::Drawing::SizeF PixelFormat System::Drawing::Imaging::PixelFormat::Format32bppArgb System::Drawing::Imaging::PixelFormat PropertyIdList {Length=0} 数组 ^ PropertyItems {Length=0} 数组 ^
RawFormat 0x0000026aa62a3488 { ...} System::Drawing::Imaging::ImageFormat^
尺寸 {Width=640 Height=480} System::Drawing::Size 标签系统::对象^ 垂直分辨率 96.000000 浮点数宽度 640 整数 nativeImage 2657511290992 __int64 原始数据数组 ^ 用户数据系统::对象^ ImageLocation System::String^
ImageRectangle {X=0 Y=0 Width=640 Height=480} System::Drawing::Rectangle ImeMode System::Windows::Forms::ImeMode::Disable System::Windows::Forms::ImeMode
InitialImage 0x0000026aa629c568 { nativeImage=2657511196256 rawData= userData= } System::Drawing::Image^ PICTUREBOXSTATE_asyncOperationInProgress 1 int PICTUREBOXSTATE_cancellationPending 2 int PICTUREBOXSTATE_in 初始化 64 int PICTUREBOXSTATE_needToLoadImageLocation 32 int PICTUREBOXSTATE_useDefaultErrorImage 8 int PICTUREBOXSTATE_useDefaultInitialImage 4 int PICTUREBOXSTATE_waitOnLoad 16 int RightToLeft System::Windows::Forms::RightToLeft::No System::Windows::Forms::RightToLeft SizeMode System::Windows::Forms::PictureBoxSizeMode::Normal System::Windows::Forms::PictureBoxSizeMode TabIndex 1 整数 TabStop false 布尔值文本“”系统::字符串^ WaitOnLoad false 布尔 borderStyle System::Windows::Forms::BorderStyle::None System::Windows::Forms::BorderStyle 内容长度 0 int currentAsyncLoadOperation System::ComponentModel::AsyncOperation^ currentAnimating false bool
defaultErrorImage 0x0000026aa629b110 { nativeImage=2657511192608 rawData= userData= } System::Drawing::Image^
defaultErrorImageForThread 0x0000026aa629b110 { nativeImage=2657511192608 rawData= userData= } System::Drawing::Image^ defaultErrorImageKey 0x0000026aa629af08 System::Object^
defaultInitialImage 0x0000026aa629c568 { nativeImage=2657511196256 rawData= userData= } System::Drawing::Image^
defaultInitialImageForThread 0x0000026aa629c568 { nativeImage=2657511196256 rawData= userData= } System::Drawing::Image^ defaultInitialImageKey 0x0000026aa629aef0 System::Object^
errorImage 0x0000026aa629b110 { nativeImage=2657511192608 rawData= userData= } System::Drawing::Image^ handleValid false bool
图像 0x0000026aa62a1fa0 { nativeImage=2657511290992 rawData= userData= } System::Drawing::Image^ imageInstallationType ImageInstallationType::DirectlySpecified ImageInstallationType imageLocation System::String^
initialImage 0x0000026aa629c568 { nativeImage=2657511196256 rawData= userData= } System::Drawing::Image^
[System::Drawing::Bitmap^] 0x0000026aa629c568 { defaultTransparentColor= } System::Drawing::Bitmap^
System::MarshalByRefObject^ 0x0000026aa629c568 { __identity= } System::MarshalByRefObject^ 标志 73744 int
FrameDimensionsList {Length=1} 数组 ^ 身高 16 英寸 HorizontalResolution 96.000000 浮点数
RED >>>>>Palette 0x0000026aa629ea60 { flags=951278840 entries={Length=0} } System::Drawing::Imaging::ColorPalette^
PhysicalDimension { width=14.000000 height=16.000000 } System::Drawing::SizeF PixelFormat System::Drawing::Imaging::PixelFormat::Format24bppRgb System::Drawing::Imaging::PixelFormat PropertyIdList {Length=0} 数组 ^ PropertyItems {Length=0} 数组 ^
RED >>>>> RawFormat 0x0000026aa629f900 { ...} System::Drawing::Imaging::ImageFormat^
尺寸 {Width=14 Height=16} System::Drawing::Size 标签系统::对象^ 垂直分辨率 96.000000 浮点数宽度 14 整数 nativeImage 2657511196256 __int64 原始数据数组 ^ 用户数据系统::对象^ 红色 >>>>>>> internalSyncObject 0x0000026aa629d900 System::Object^ loadCompletedDelegate System::Threading::SendOrPostCallback^ loadCompletedKey 0x0000026aa629af20 系统::对象^ loadProgressChangedKey 0x0000026aa629af38 系统::对象^ loadProgressDelegate System::Threading::SendOrPostCallback^ localImageStreamReader System::IO::StreamReader^
pictureBoxState { data=12 } System::Collections::Specialized::BitVector32 readBlockSize 4096 整数读取缓冲区数组 ^
savedSize {Width=640 Height=480} System::Drawing::Size sizeMode System::Windows::Forms::PictureBoxSizeMode::Normal System::Windows::Forms::PictureBoxSizeMode tempDownloadStream System::IO::MemoryStream^ totalBytesRead 0 int uriImageStream System::IO::Stream^

【问题讨论】：

由于我没有看到任何同步，我假设opencv_gui::video_cap 在主 GUI 线程上运行。因此，看到无限循环已经存在潜在问题的迹象。虽然waitKey 可能有点用，但除了 OpenCV UI 之外，我不会依赖它。无论如何，这在 GUI 应用程序中是一个非常尴尬的设计。您已经在帧之间等待，为什么不使用计时器？
感谢 Dan 的评论，我打算尽快清理有关循环的代码，但删除循环并手动捕获仍然不会在图片框上显示框架，这是我的主要问题。跨度>
您可以尝试在调试器中单步执行该功能吗？ cvImage.cols, cvImage.rows, cvImage.step 的值是多少？ cvImage.data 是否包含一些合理的值？顺便说一句，OpenCV 图像是 BGR，您将数据解释为 RGB。你可能需要一个cvtColor 来切换它。
嗨，丹，我已将调试日志的副本放入问题中。图像大小和数据参数为零，但其他参数具有合理的值（640 和 480）...我还标明了哪些调试行以红色突出显示供您查看。感谢您迄今为止的帮助。

标签： c++ winforms visual-studio opencv video-capture

【解决方案1】：

不得不稍微编辑我的代码，但我使用此处提供的答案几乎解决了我的问题： https://stackoverflow.com/a/12628861/5728859

【讨论】：

【解决方案2】：

试试这个

private: System::Void button2_MouseClick(System::Object^  sender, System::Windows::Forms::MouseEventArgs^  e)
{
    if (button2->Text == "Stop")
    {
        button2->Text = "Start";

    }
    else if (button2->Text == "Start")
    {
        button2->Text = "Stop";

    }

     VideoCapture capture(0);
     Mat frame;

     while (button2->Text == "Stop")
     {
         capture.read(frame);
         System::Drawing::Graphics^ graphics2 = pictureBox1->CreateGraphics();
         System::IntPtr ptr2(frame.ptr());
         System::Drawing::Bitmap^ b2 = gcnew System::Drawing::Bitmap(frame.cols,
             frame.rows, frame.step, System::Drawing::Imaging::PixelFormat::Format24bppRgb, ptr2);
         System::Drawing::RectangleF rect2(0, 0, pictureBox1->Width, pictureBox1->Height);
         graphics2->DrawImage(b2, rect2);

     }
 }

【讨论】：