我正在尝试调整网络摄像头的亮度。我需要用不同的亮度设置拍摄 3 张不同的照片。我不想让它手动，所以如果想在程序中包含设置。
下面是我正在使用的代码。使用 GetFrame() 方法从网络摄像头获取下一张图片。我知道有 DirectShow (iamvideoprocamp)，我阅读了其他问题，但我仍然不知道如何集成它。有人可以给我一个提示或 c# 中的示例。谢谢。
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;
}