如何将立体图像与 EmguCV 混合？

Question

我目前正在尝试将两个单独的相机图像合并为一个图像Anaglyph。结果应该类似于this image here。

这是我编写的用于捕获两个相机图像并将它们转换为黑白的代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using Emgu.Util;

namespace CameraStereoCapture {

    public partial class CameraStereoCapture : Form {

        private bool captureInProgress;

        private VideoCapture cameraLeft = null;
        private VideoCapture cameraRight = null;

        private Mat leftRawFrame;
        private Mat rightRawFrame;

        private Mat leftGrayFrame;
        private Mat rightGrayFrame;

        private Mat stereoFrame;

        public CameraStereoCapture() {
            InitializeComponent();
            CvInvoke.UseOpenCL = false;
            try {
                cameraLeft = new VideoCapture(1);
                cameraLeft.ImageGrabbed += ProcessFrame;
                cameraRight = new VideoCapture(0);
                cameraRight.ImageGrabbed += ProcessFrame;
            } catch (NullReferenceException ex) {
                MessageBox.Show(ex.Message);
            }
            leftRawFrame = new Mat();
            rightRawFrame = new Mat();
            leftGrayFrame = new Mat();
            rightGrayFrame = new Mat();
            stereoFrame = new Mat();
        }

        private void cmdCapture_Click(object sender, EventArgs e) {
            if (cameraLeft != null) {
                if (captureInProgress) {
                    // stop the capture
                    cmdCapture.Text = "Start Capture";
                    cameraLeft.Pause();
                    cameraRight.Pause();
                } else {
                    // start the capture
                    cmdCapture.Text = "Stop Capture";
                    cameraLeft.Start();
                    cameraRight.Start();
                }
                captureInProgress = !captureInProgress;
            }
        }

        private void ProcessFrame(object sender, EventArgs arg) {
            // capture and cache image from left camera
            if (cameraLeft != null && cameraLeft.Ptr != IntPtr.Zero) {
                cameraLeft.Retrieve(leftRawFrame, 0);
                imgLeft.Image = leftRawFrame;
            }
            // capture and cache image from right camera
            if (cameraRight != null && cameraRight.Ptr != IntPtr.Zero) {
                cameraRight.Retrieve(rightRawFrame, 0);
                imgRight.Image = rightRawFrame;
            }
            // calculate stereo image by combining the left and right image
            if (leftRawFrame != null && rightRawFrame!=null) {
                CvInvoke.CvtColor(leftRawFrame, leftGrayFrame, ColorConversion.Bgr2Gray);
                CvInvoke.CvtColor(rightRawFrame, rightGrayFrame, ColorConversion.Bgr2Gray);
                // TODO: how to convert 'leftRawImage to Cyan' ???
                // TODO: how to convert 'rightRawImage to Magenta' ???
                CvInvoke.AddWeighted(leftGrayFrame, 0.5, rightGrayFrame, 0.5, 1.0, stereoFrame);
                imgStereo.Image = stereoFrame;
            }
        }

    }

}

我的问题是，如何将灰色图像转换为 Cyan 和 Magenta 或 Red 和 Blue（cp. 在代码 sn-p 中标记为 TODO: 的行）？

Answer 1

要制作 Red-Cyan Anaglyph 立体图像，请将 imgLeft 置于 imgStereo 的红色通道，将 imgRight 置于 imgStereo 的绿色和蓝色通道

假设所有三个图像（L、R、S）大小相同，代码将如下所示：

for(i=0;i<imgStereo->height;i++)
{
   for(j=0;j<imgStereo->width;j++)
   {
      imgStereo.at<Vec3b>(i,j)[0] = imgRight.at<uchar>(i,j);   // B
      imgStereo.at<Vec3b>(i,j)[1] = imgRight.at<uchar>(i,j);   // G
      imgStereo.at<Vec3b>(i,j)[2] = imgLeft.at<uchar>(i,j);    // R
    }
}

Answer 2

这是我的 EmguCV 解决方案，用于从两个摄像头输入生成立体图像。两幅彩色图像先转换为灰度图像，然后合并到最终RGB图像的相应颜色通道中。

与只提取一个源图像的红色通道和另一源图像的绿色/蓝色通道的方法相比，这种方法的优点是不会丢失任何信息。

#region Usings
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using Emgu.CV.Util;
using Emgu.Util;
#endregion

namespace WallECtrl {

    public delegate void ImageAvailable(Mat leftFrame, Mat rightFrame, Mat stereoFrame);

    public class StereoEngine {

        public event ImageAvailable ImageAvailableEvent;

        private bool capturing;
        private bool colorPreview;

        private VideoCapture cameraLeft = null;
        private VideoCapture cameraRight = null;

        private Mat matLeftColourFrame;
        private Mat matRightColourFrame;
        private Mat matLeftGrayFrame;
        private Mat matRightGrayFrame;
        private Mat matStereoFrame;

        public StereoEngine() {
            CvInvoke.UseOpenCL = false;
            cameraLeft = new VideoCapture(0);
            cameraLeft.ImageGrabbed += ProcessFrame;
            cameraRight = new VideoCapture(1);
            cameraRight.ImageGrabbed += ProcessFrame;
            matLeftColourFrame = new Mat();
            matRightColourFrame = new Mat();
            matLeftGrayFrame = new Mat();
            matRightGrayFrame = new Mat();
            matStereoFrame = new Mat();
        }

        public bool Capturing {
            get {
                return capturing;
            }
        }

        public bool ColorPreview {
            get {
                return colorPreview;
            }
            set {
                colorPreview = value;
            }
        }

        public void startCapture() {
            if (cameraLeft != null && cameraRight != null) {
                if (!capturing) {
                    cameraLeft.Start();
                    cameraRight.Start();
                    capturing = !capturing;
                }
            }
        }

        public void stopCapture() {
            if (cameraLeft != null && cameraRight != null) {
                if (capturing) {
                    cameraLeft.Pause();
                    cameraRight.Pause();
                    capturing = !capturing;
                }
            }
        }

        private void ProcessFrame(object sender, EventArgs arg) {

            // capture and cache image from left camera
            if (cameraLeft != null && cameraLeft.Ptr != IntPtr.Zero) {
                cameraLeft.Retrieve(matLeftColourFrame, 0);
            }

            // capture and cache image from right camera
            if (cameraRight != null && cameraRight.Ptr != IntPtr.Zero) {
                cameraRight.Retrieve(matRightColourFrame, 0);
            }

            // calculate stereo image by combining the left and right image
            if (matLeftColourFrame != null && matRightColourFrame!=null) {

                CvInvoke.CvtColor(matLeftColourFrame, matLeftGrayFrame, ColorConversion.Bgr2Gray);
                CvInvoke.CvtColor(matRightColourFrame, matRightGrayFrame, ColorConversion.Bgr2Gray);

                using (VectorOfMat vm = new VectorOfMat(matRightGrayFrame, matRightGrayFrame, matLeftGrayFrame)) {
                    CvInvoke.Merge(vm, matStereoFrame);
                }

                // inform gui + network about new stereo image available
                if(ImageAvailableEvent != null) {
                    if (colorPreview) {
                        ImageAvailableEvent(matLeftColourFrame, matRightColourFrame, matStereoFrame);
                    } else {
                        ImageAvailableEvent(matLeftGrayFrame, matRightGrayFrame, matStereoFrame);
                    }
                }

            }

        }

        public void exit() {
            if(cameraLeft != null) {
                cameraLeft.Stop();
                cameraLeft.Dispose();
            }
            if (cameraRight != null) {
                cameraRight.Stop();
                cameraRight.Dispose();
            }
        }

    }

}