OpenCVSharp入门教程基础篇③——从本地摄像头获取媒体流

亦凉 2023-01-23 07:53 802阅读 0赞

### 文章目录 ###

*  一、界面布局
 *  二、功能实现
 *   *  2.1 打开摄像头
     *  2.2 运行摄像头后台任务
 *  三、异常报错
 *  四、运行
 *  五、Demo源码

# 一、界面布局 #

*  两个`Button`
 *  一个`PictureBox`
 *  一个`BackgroundWorker cameraWorker`  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2thbmd3ZWlqaWFu_size_16_color_FFFFFF_t_70]

# 二、功能实现 #

## 2.1 打开摄像头 ##

*  打开摄像头
 *  判断摄像头是否打开，否：提示并退出
 *  摄像头后台任务`cameraWorker`开始运行

private void openCameraBtn_Click(object sender, EventArgs e)
    { 
        if (cameraWorker.IsBusy)
        { 
            closeCamera();
        }
        else
        { 
            openCamera();
        }
    }
    
    private void openCamera()
    { 
        capture.Open(0, VideoCaptureAPIs.ANY);
        if (!capture.IsOpened())
        { 
            Close();
            MessageBox.Show("打开摄像头失败");
            return;
        }
        openCameraBtn.Text = "关闭摄像头";
        cameraWorker.RunWorkerAsync();
    }
    
    private void closeCamera()
    { 
        openCameraBtn.Text = "打开摄像头";
        cameraWorker.CancelAsync();
        capture.Release();
        pictureBox1.Image = null;
    }

## 2.2 运行摄像头后台任务 ##

*  `while`死循环
 *  获取摄像头`frameMat`
 *  转换成`Bitmap`
 *  复制给`pictureBox1`

private void cameraWorker_DoWork(object sender, DoWorkEventArgs e)
    { 
        var bgWorker = (BackgroundWorker)sender;
    
        while (!bgWorker.CancellationPending)
        { 
            using (var frameMat = capture.RetrieveMat())
            { 
                var frameBitmap = BitmapConverter.ToBitmap(frameMat);
                bgWorker.ReportProgress(0, frameBitmap);
            }
            Thread.Sleep(100);
        }
    }
    
    private void cameraWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
    { 
        var frameBitmap = (Bitmap)e.UserState;
        pictureBox1.Image?.Dispose();
        pictureBox1.Image = frameBitmap;
    }

# 三、异常报错 #

System.TypeInitializationException:““OpenCvSharp.Internal.NativeMethods”的类型初始值设定项引发异常。”
    
    内部异常
    DllNotFoundException: 无法加载 DLL“OpenCvSharpExtern”: 找不到指定的模块。 (异常来自 HRESULT:0x8007007E)。

因为还少了一点dll

*  点击下载[OpenCVSharp dll.zip][]
 *  放到`\bin\Debug\下面`  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2thbmd3ZWlqaWFu_size_16_color_FFFFFF_t_70 1]

# 四、运行 #

*  堪称完美  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2thbmd3ZWlqaWFu_size_16_color_FFFFFF_t_70 2]

# 五、Demo源码 #

[OpenCVSharpDemo工程源码点击下载][OpenCVSharpDemo]

***觉得好，就一键三连呗（点赞+收藏+关注）***

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2thbmd3ZWlqaWFu_size_16_color_FFFFFF_t_70]: /images/20221004/39c4380cc4184ccaae41f0bfe2f38da0.png
[OpenCVSharp dll.zip]: https://download.csdn.net/download/kangweijian/20247973
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2thbmd3ZWlqaWFu_size_16_color_FFFFFF_t_70 1]: /images/20221004/44afebfe53524c048ab7eb4dab2b9cb9.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2thbmd3ZWlqaWFu_size_16_color_FFFFFF_t_70 2]: /images/20221004/1665d9bf27a94ccea59b9f6725528a5d.png
[OpenCVSharpDemo]: https://download.csdn.net/download/kangweijian/20259433