refactor: 白底/黑底检测算法迁至 BackgroundDefectAnalyzer

- 在 XP.ImageProcessing.Processors 新增静态分析类与 BackgroundDefectMode/BackgroundDefectBlob。 - MainViewModel 仅负责灰度 ROI 提取、坐标平移与 Prism 事件发布。
2026-05-14 16:27:16 +08:00
parent 1ad33cc3e6
commit baef619bd4
2 changed files with 139 additions and 143 deletions
@@ -0,0 +1,102 @@
+// ============================================================================
+// Copyright © 2026 Hexagon Technology Center GmbH. All Rights Reserved.
+// 文件名: BackgroundDefectAnalyzer.cs
+// 描述: 白底/黑底对比下的缺陷斑点分析（仅 ROI 内计算，不接入流水线算子）
+// 算法: Otsu 二值化 → 形态学开运算 → 外轮廓 → 面积过滤 → 外接矩形等效圆
+// 作者: 李伟 wei.lw.li@hexagon.com
+// ============================================================================
+
+using System.Drawing;
+using Emgu.CV;
+using Emgu.CV.CvEnum;
+using Emgu.CV.Structure;
+using Emgu.CV.Util;
+
+namespace XP.ImageProcessing.Processors;
+
+/// <summary>
+/// 底色类型：决定 Otsu 后保留的前景是暗区还是亮区。
+/// </summary>
+public enum BackgroundDefectMode
+{
+    /// <summary>白底图像上检测偏暗区域（BinaryInv + Otsu）。</summary>
+    WhiteBackground,
+
+    /// <summary>黑底图像上检测偏亮区域（Binary + Otsu）。</summary>
+    BlackBackground
+}
+
+/// <summary>
+/// 单个斑点，坐标相对于输入 ROI 左上角；<see cref="SizeMicrometers"/> 与主界面标注逻辑一致（等效直径，微米）。
+/// </summary>
+public readonly record struct BackgroundDefectBlob(Point CenterInRoi, int RadiusPixels, double SizeMicrometers);
+
+/// <summary>
+/// 在灰度 ROI 上执行底色缺陷斑点检测。调用方负责构造与释放 <paramref name="roiGray"/>。
+/// </summary>
+public static class BackgroundDefectAnalyzer
+{
+    /// <summary>
+    /// 在 ROI 灰度图上检测斑点。
+    /// </summary>
+    /// <param name="roiGray">ROI 灰度图（单通道 8 位）。</param>
+    /// <param name="mode">白底或黑底模式。</param>
+    /// <param name="minAreaPixels">轮廓最小面积（像素²），小于此值的轮廓丢弃。</param>
+    /// <param name="mmPerPixel">像素物理尺寸（毫米/像素），用于等效直径换算。</param>
+    /// <param name="morphKernelSize">形态学开运算核尺寸（奇数，默认 3）。</param>
+    public static List<BackgroundDefectBlob> DetectBlobs(
+        Image<Gray, byte> roiGray,
+        BackgroundDefectMode mode,
+        int minAreaPixels = 50,
+        double mmPerPixel = 0.139,
+        int morphKernelSize = 3)
+    {
+        if (roiGray == null) throw new ArgumentNullException(nameof(roiGray));
+        if (minAreaPixels < 1) minAreaPixels = 1;
+        if (mmPerPixel <= 0) mmPerPixel = 0.139;
+        if (morphKernelSize < 1) morphKernelSize = 1;
+        if ((morphKernelSize & 1) == 0) morphKernelSize++;
+
+        int rw = roiGray.Width;
+        int rh = roiGray.Height;
+        if (rw < 1 || rh < 1) return new List<BackgroundDefectBlob>();
+
+        var thresholdType = mode == BackgroundDefectMode.WhiteBackground
+            ? ThresholdType.BinaryInv | ThresholdType.Otsu
+            : ThresholdType.Binary | ThresholdType.Otsu;
+
+        using var binary = new Image<Gray, byte>(rw, rh);
+        CvInvoke.Threshold(roiGray, binary, 0, 255, thresholdType);
+
+        using var kernel = CvInvoke.GetStructuringElement(
+            ElementShape.Ellipse, new Size(morphKernelSize, morphKernelSize), new Point(-1, -1));
+        CvInvoke.MorphologyEx(binary, binary, MorphOp.Open, kernel, new Point(-1, -1), 1,
+            BorderType.Default, new MCvScalar(0));
+
+        using var contours = new VectorOfVectorOfPoint();
+        using var hierarchy = new Mat();
+        CvInvoke.FindContours(binary, contours, hierarchy, RetrType.External, ChainApproxMethod.ChainApproxSimple);
+
+        var result = new List<BackgroundDefectBlob>();
+
+        for (int i = 0; i < contours.Size; i++)
+        {
+            double area = CvInvoke.ContourArea(contours[i]);
+            if (area < minAreaPixels) continue;
+
+            var boundRect = CvInvoke.BoundingRectangle(contours[i]);
+            double radiusF = Math.Max(boundRect.Width, boundRect.Height) / 2.0;
+            var centerF = new PointF(
+                boundRect.X + boundRect.Width / 2.0f,
+                boundRect.Y + boundRect.Height / 2.0f);
+
+            var centerInRoi = new Point((int)centerF.X, (int)centerF.Y);
+            int radiusPx = (int)radiusF;
+            double sizeMicrometers = radiusF * 2.0 * mmPerPixel * 1000.0;
+
+            result.Add(new BackgroundDefectBlob(centerInRoi, radiusPx, sizeMicrometers));
+        }
+
+        return result;
+    }
+}