opencvsharp在局部roi中找直线边 亚像素搜索边 编写搜索边函数 参数设定找边的起始方向从左到右、从右到左、从上到下、从下到上、从白或黑边起

以下是使用OpenCvSharp实现亚像素搜索边的示例代码：

using OpenCvSharp;
using System;

namespace EdgeDetection
{
    class Program
    {
        static void Main(string[] args)
        {
            Mat image = Cv2.ImRead("test.jpg", ImreadModes.GrayScale);

            // 设置ROI(感兴趣区域)
            Rect roi = new Rect(100, 100, 200, 200);
            Mat roiImage = new Mat(image, roi);

            // 创建一个空白图像来显示结果
            Mat result = new Mat(roiImage.Rows, roiImage.Cols, MatType.CV_8UC1, Scalar.Black);

            // 定义搜索方向和阈值
            int threshold = 50;
            LineSegmentPoint startPoint = new LineSegmentPoint(0, roiImage.Rows / 2, roiImage.Cols, roiImage.Rows / 2);
            ScanDirection direction = ScanDirection.RightToLeft;
            EdgeColor color = EdgeColor.Black;

            // 在ROI中搜索直线边
            Point2f edgePoint = FindEdge(roiImage, startPoint, direction, threshold, color);

            // 将结果绘制到空白图像上
            Cv2.Line(result, startPoint.P1.ToPoint(), edgePoint.ToPoint(), Scalar.White, 1, LineTypes.AntiAlias);

            // 显示结果
            Cv2.ImShow("Result", result);
            Cv2.WaitKey(0);
        }

        static Point2f FindEdge(Mat image, LineSegmentPoint startPoint, ScanDirection direction, int threshold, EdgeColor color)
        {
            int step = direction == ScanDirection.LeftToRight || direction == ScanDirection.RightToLeft ? image.Step() : 1;
            int scanWidth = direction == ScanDirection.LeftToRight || direction == ScanDirection.RightToLeft ? image.Rows : image.Cols;
            int scanHeight = direction == ScanDirection.LeftToRight || direction == ScanDirection.RightToLeft ? image.Cols : image.Rows;

            int x = startPoint.P1.X;
            int y = startPoint.P1.Y;

            float gradient = 0;
            int count = 0;
            bool foundEdge = false;

            while (x >= 0 && x < scanWidth && y >= 0 && y < scanHeight)
            {
                byte pixelValue = color == EdgeColor.Black ? image.Get<byte>(y, x) : (byte)(255 - image.Get<byte>(y, x));
                float distance = direction == ScanDirection.LeftToRight || direction == ScanDirection.TopToBottom ? (float)(x - startPoint.P1.X) : (float)(y - startPoint.P1.Y);

                if (Math.Abs(pixelValue - threshold) < Math.Abs(gradient - threshold))
                {
                    gradient = pixelValue;
                    count = 1;
                    foundEdge = true;
                }
                else if (foundEdge && Math.Abs(pixelValue - gradient) <= 1)
                {
                    gradient = ((gradient * count) + pixelValue) / (count + 1);
                    count++;
                }
                else if (foundEdge)
                {
                    break;
                }

                switch (direction)
                {
                    case ScanDirection.LeftToRight:
                        x++;
                        break;
                    case ScanDirection.RightToLeft:
                        x--;
                        break;
                    case ScanDirection.TopToBottom:
                        y++;
                        break;
                    case ScanDirection.BottomToTop:
                        y--;
                        break;
                }
            }

            Point2f edgePoint;

            if (direction == ScanDirection.LeftToRight || direction == ScanDirection.RightToLeft)
            {
                edgePoint = new Point2f(x - (float)count / 2, startPoint.P1.Y);
            }
            else
            {
                edgePoint = new Point2f(startPoint.P1.X, y - (float)count / 2);
            }

            return edgePoint;
        }
    }

    enum ScanDirection
    {
        LeftToRight,
        RightToLeft,
        TopToBottom,
        BottomToTop
    }

    enum EdgeColor
    {
        Black,
        White
    }
}

该函数的参数如下：

- `image`：输入图像的ROI
- `startPoint`：搜索边的起始点
- `direction`：搜索的方向
- `threshold`：搜索边时使用的阈值
- `color`：搜索的边是黑色还是白色

该函数返回一个Point2f类型的点，表示找到的边界的位置。