Question

我正在尝试调整网络摄像头的亮度。我需要使用不同的亮度设置拍摄3张不同的照片。如果想在程序中包含设置，我不想手动编写。

下面是我正在使用的代码。使用方法GetFrame（）a从网络摄像头获取下一张图片。我知道有DirectShow（iamvideoprocamp），我读了其他问题，但我仍然不知道如何整合它。有人可以在c＃中给我一个提示或示例。感谢。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using System.Drawing;
using System.Threading;
using DirectShowLib;

namespace Kugel
{
    class Frames
    {
        // property variables
        private int m_Width = 640;
        private int m_Height = 480;
        private int mCapHwnd;

        // global variables to make the video capture go faster
        private IDataObject tempObj;
        private System.Drawing.Image tempImg;


        #region API Declarations

        [DllImport("user32", EntryPoint = "SendMessage")]
        public static extern int SendMessage(int hWnd, uint Msg, int wParam, int lParam);

        [DllImport("avicap32.dll", EntryPoint = "capCreateCaptureWindowA")]
        public static extern int capCreateCaptureWindowA(string lpszWindowName, int dwStyle, int X, int Y, int nWidth, int nHeight, int hwndParent, int nID);

        [DllImport("user32", EntryPoint = "OpenClipboard")]
        public static extern int OpenClipboard(int hWnd);

        [DllImport("user32", EntryPoint = "EmptyClipboard")]
        public static extern int EmptyClipboard();

        [DllImport("user32", EntryPoint = "CloseClipboard")]
        public static extern int CloseClipboard();

        #endregion

        #region API Constants

        public const int WM_USER = 1024;

        public const int WM_CAP_CONNECT = 1034;
        public const int WM_CAP_DISCONNECT = 1035;
        public const int WM_CAP_GET_FRAME = 1084;
        public const int WM_CAP_COPY = 1054;

        public const int WM_CAP_START = WM_USER;

        public const int WM_CAP_DLG_VIDEOFORMAT = WM_CAP_START + 41;
        public const int WM_CAP_DLG_VIDEOSOURCE = WM_CAP_START + 42;
        public const int WM_CAP_DLG_VIDEODISPLAY = WM_CAP_START + 43;
        public const int WM_CAP_GET_VIDEOFORMAT = WM_CAP_START + 44;
        public const int WM_CAP_SET_VIDEOFORMAT = WM_CAP_START + 45;
        public const int WM_CAP_DLG_VIDEOCOMPRESSION = WM_CAP_START + 46;
        public const int WM_CAP_SET_PREVIEW = WM_CAP_START + 50;

        #endregion

        #region Start and Stop Capture Functions

        /// <summary>
        /// Starts the video capture
        /// </summary>      
        public void Start()
        {
            try
            {
                // for safety, call stop, just in case we are already running
                this.Stop();

                // setup a capture window
                mCapHwnd = capCreateCaptureWindowA("WebCap", 0, 0, 0, m_Width, m_Height, 0, 0);

                // connect to the capture device
                Application.DoEvents();
                SendMessage(mCapHwnd, WM_CAP_CONNECT, 0, 0);
                SendMessage(mCapHwnd, WM_CAP_SET_PREVIEW, 0, 0);
            }

            catch (Exception ex)
            {
              //  MessageBox.Show("An error ocurred while starting the video capture. Check that your webcamera is connected properly and turned on.\r\n\n" + excep.Message);
                this.Stop();
            }
        }

        /// <summary>
        /// Stops the video capture
        /// </summary>
        public void Stop()
        {
            try
            {
                // disconnect from the video source
                Application.DoEvents();
                SendMessage(mCapHwnd, WM_CAP_DISCONNECT, 0, 0);
            }

            catch (Exception ex)
            { // don't raise an error here.
            }

        }

        #endregion

        public void Prefer()
        {
           try
            {
                SendMessage(mCapHwnd, WM_CAP_DLG_VIDEOSOURCE, 0, 0);
            }
           catch (Exception ex)
           {
             //  MessageBox.Show("An error ocurred while capturing the video image. The video capture will now be terminated.\r\n\n" + excep.Message);
           }
        }

        public Image GetFrame()
        {
           try
            {
                // get the next frame;
                SendMessage(mCapHwnd, WM_CAP_GET_FRAME, 0, 0);

                // copy the frame to the clipboard
                SendMessage(mCapHwnd, WM_CAP_COPY, 0, 0);

                // get from the clipboard
                tempObj = Clipboard.GetDataObject();
                tempImg = (System.Drawing.Bitmap)tempObj.GetData(System.Windows.Forms.DataFormats.Bitmap);                   
                return tempImg;
           }
           catch (Exception ex)
           {
             //  MessageBox.Show("An error ocurred while capturing the video image. The video capture will now be terminated.\r\n\n" + excep.Message);
               this.Stop();
           }
           return null;
        }

Answer 1

您几乎无法集成DirectShow的IAMVideoProcAmp和您提供的代码段，因为您的GetFrame使用完全不同的API：Video for Windows。

这是两个不同的API，可能共享相同的视频捕获设备。那么，有可能你在DirectShow中找到相同的设备，然后你开始构建捕获图，你获得了接口，过滤器将希望接受你的亮度变化而不开始视频捕获，然后它会想要制作它们是持久的，因此可通过VfW API用于同一设备。有了所有这些假设和复杂性，您可以通过DirectShow进行调整，同时通过VfW进行捕获。但是，完全转移到DirectShow看起来更合理。

Answer 2

使用以下代码段设置缩放，聚焦和曝光。

videoDevice.SetCameraProperty(
            CameraControlProperty.Zoom,
            zoomValue,
            CameraControlFlags.Manual);

        videoDevice.SetCameraProperty(
            CameraControlProperty.Focus,
            focusValue,
            CameraControlFlags.Manual);

        videoDevice.SetCameraProperty(
            CameraControlProperty.Exposure,
            exposureValue,
            CameraControlFlags.Manual);

要访问其他相机属性，如亮度，对比度，请参阅IAMVideoProcAmp实施。

videoDevice.SetVideoProperty(
VideoProcAmpProperty.Brightness,
brightnessValue,
VideoProcAmpFlags.Manual);

videoDevice.SetVideoProperty(
VideoProcAmpProperty.Contrast,
contrastValue,
VideoProcAmpFlags.Manual);

videoDevice.SetVideoProperty(
VideoProcAmpProperty.Saturation,
saturationValue,
VideoProcAmpFlags.Manual);

videoDevice.SetVideoProperty(
VideoProcAmpProperty.Sharpness,
sharpnessValue,
VideoProcAmpFlags.Manual);

videoDevice.SetVideoProperty(
VideoProcAmpProperty.WhiteBalance,
whiteBalanceValue,
VideoProcAmpFlags.Manual);

videoDevice.SetVideoProperty(
VideoProcAmpProperty.BacklightCompensation,
backlightCompensationValue,
VideoProcAmpFlags.Manual);

调整网络摄像头亮度（曝光/增益）C＃

2 个答案: