c#实现包裹扣面单的几种方式

无论是跨境电商还是制造业分拣设备，在包裹流转出入库的场景，为了保证包裹分拣计划和测量数据绑定真实性，经常会遇到面单扣取的需求，下面我就通过两种实现原理来实现这一功能。

一:OpenCVSharp 通过面单轮廓/颜色/边缘等组合检测实现

二:通过OCR识别面单内容,根据所有切割点坐标点最小外界矩形来定位面单位置(扣面单的场景需求是看清面单内容，当然想要扣取完整面单图片，可以添加面单尺寸,规则信息等维度计算或者直接用第三种方式)

三:YOLO+Labelme标定工具，通过模型训练定位扣取(这个抽时间单独展开一篇解释)

方式一:OpencvSharp 通过轮廓/颜色/边缘检测

这种方式对于包裹和面单颜色有明显差异的场景很友好，对于包裹颜色和面单颜色接近的效果一般（建议考虑第二种方式），虽然可以根据面单样式或者文字聚集密度等多重维度来组合分析，但是过于复杂，并且定制化程度很高，废话少说，先看看效果:

原图：

通过显示增强后的效果图:

废话少说，附上核心代码:

复制代码

staticvoidProcessSingleImage(string imagePath)
{
if (!File.Exists(imagePath))
    {
        Console.WriteLine("文件不存在!");
        Console.ReadKey();
return;
    }

try
    {
        Console.WriteLine($"处理: {Path.GetFileName(imagePath)}");

var stopwatch = Stopwatch.StartNew();

// 检测面单
var results = _detector.DetectLabels(imagePath);

        stopwatch.Stop();
        Console.WriteLine($"检测耗时: {stopwatch.ElapsedMilliseconds}ms");
        Console.WriteLine($"找到 {results.Count} 个面单区域");

if (results.Count == 0)
        {
            Console.WriteLine("未检测到面单!");
            Console.ReadKey();
return;
        }

// 显示结果
foreach (var result in results)
        {
            Console.WriteLine($"- {result.DetectionMethod}: 置信度 {result.Confidence:F2}, " +
$"位置 [{result.BoundingBox.X}, {result.BoundingBox.Y}, " +
$"{result.BoundingBox.Width}, {result.BoundingBox.Height}]");
        }

// 创建输出目录
var outputDir = _config.OutputDirectory;
if (!Directory.Exists(outputDir))
            Directory.CreateDirectory(outputDir);

var baseName = Path.GetFileNameWithoutExtension(imagePath);

// 保存可视化结果
if (_config.SaveVisualized)
        {
using (var original = new Bitmap(imagePath))
            {
                Bitmap bitResult = ImageProcessor.DrawBoundingBoxesSafe(original, results);

var visPath = Path.Combine(outputDir, $"{baseName}_detected.png");
                ImageProcessor.SaveImage(bitResult, visPath);
                Console.WriteLine($"可视化结果已保存: {visPath}");
            }
        }

// 保存抠图结果 
if (_config.SaveCropped)
        {
using (var mat = Cv2.ImRead(imagePath))
            {
for (int i = 0; i < results.Count; i++)
                {
var cropped = _detector.CropLabel(mat, results[i].BoundingBox);
if (cropped != null)
                    {
// 图像增强
                        _detector.EnhanceImage(ref cropped);

var cropPath = Path.Combine(outputDir, $"{baseName}_label_{i + 1}.png");
                        Console.WriteLine(cropped);

                        ImageProcessor.SaveImage(cropped, cropPath);
                        Console.WriteLine($"抠图已保存: {cropPath}");

                        cropped.Dispose();
                    }
                }
            }
        }

// 保存检测结果到JSON
        SaveResultsToJson(results, Path.Combine(outputDir, $"{baseName}_results.json"));

        Console.WriteLine("\n处理完成! 按任意键继续..."); 
    }
catch (Exception ex)
    {
        Console.WriteLine($"处理失败: {ex.Message}");
    }
}

通过轮廓检测、颜色检测和边缘检测三种方式组合定位面单位置

复制代码

public List<DetectionResult> DetectLabels(string imagePath)
    {
var results = new List<DetectionResult>();

using (var mat = Cv2.ImRead(imagePath, OpenCvSharp.ImreadModes.Color))
        {
if (mat.Empty())
thrownew FileNotFoundException($"无法加载图像: {imagePath}");

// 方法1: 轮廓检测
var contourResults = DetectByContours(mat);
            results.AddRange(contourResults);

// 方法2: 颜色检测
var colorResults = DetectByColor(mat);
            results.AddRange(colorResults);

// 方法3: 边缘检测
var edgeResults = DetectByEdges(mat);
            results.AddRange(edgeResults);
        }

// 合并和筛选结果
return FilterResults(results);
    }

轮廓检测

复制代码

private List<DetectionResult> DetectByContours(OpenCvSharp.Mat src)
    {
var results = new List<DetectionResult>(); 
using (var gray = new OpenCvSharp.Mat())
using (var binary = new OpenCvSharp.Mat())
        {
            Cv2.CvtColor(src, gray, ColorConversionCodes.BGR2GRAY);

// 二值化
            Cv2.Threshold(gray, binary, 0, 255, ThresholdTypes.Binary | ThresholdTypes.Otsu);

// 形态学操作
var kernel = Cv2.GetStructuringElement(MorphShapes.Rect, new OpenCvSharp.Size(3, 3));
            Cv2.MorphologyEx(binary, binary, MorphTypes.Close, kernel);

// 查找轮廓
            Cv2.FindContours(binary, outvar contours, outvar hierarchy,
                RetrievalModes.External, ContourApproximationModes.ApproxSimple);

foreach (var contour in contours)
            {
var area = Cv2.ContourArea(contour); 
if (area < _minArea || area > _maxArea)
continue;

                Console.WriteLine($"面积：{area}");
var rect = Cv2.BoundingRect(contour);

// 计算宽高比
var aspectRatio = (double)rect.Width / rect.Height;

// 面单通常为矩形，宽高比在一定范围内
if (aspectRatio > 0.5 && aspectRatio < 3.0)
                {
// 计算矩形度
var rectArea = rect.Width * rect.Height;
var rectangularity = area / rectArea;
Console.WriteLine(rectangularity);
if (rectangularity > 0.55)
                    {
                        results.Add(new DetectionResult
                        {
                            BoundingBox = rect.ToRectangle(),
                            Confidence = rectangularity,
                            DetectionMethod = "Contour"
                        });
                    }
                }
            }
        }

return results;
    }

2.颜色检测

复制代码

private List<DetectionResult> DetectByColor(OpenCvSharp.Mat src)
    {
var results = new List<DetectionResult>();

using (var hsv = new OpenCvSharp.Mat())
using (var mask = new OpenCvSharp.Mat())
        {
// 转换到HSV色彩空间
            Cv2.CvtColor(src, hsv, ColorConversionCodes.BGR2HSV);

// 定义白色/浅色范围
var lowerWhite1 = new Scalar(0, 0, 200);
var upperWhite1 = new Scalar(180, 30, 255);
var lowerWhite2 = new Scalar(0, 0, 180);
var upperWhite2 = new Scalar(180, 80, 255);

using (var mask1 = new OpenCvSharp.Mat())
using (var mask2 = new OpenCvSharp.Mat())
            {
                Cv2.InRange(hsv, lowerWhite1, upperWhite1, mask1);
                Cv2.InRange(hsv, lowerWhite2, upperWhite2, mask2);
                Cv2.BitwiseOr(mask1, mask2, mask);
            }

// 形态学操作
var kernel = Cv2.GetStructuringElement(MorphShapes.Rect, new OpenCvSharp.Size(5, 5));
            Cv2.MorphologyEx(mask, mask, MorphTypes.Close, kernel);
            Cv2.MorphologyEx(mask, mask, MorphTypes.Open, kernel);

// 查找轮廓
            Cv2.FindContours(mask, outvar contours, outvar hierarchy,
                RetrievalModes.External, ContourApproximationModes.ApproxSimple);

foreach (var contour in contours)
            {
var area = Cv2.ContourArea(contour);

if (area < _minArea || area > _maxArea)
continue;

var rect = Cv2.BoundingRect(contour);

// 计算颜色均匀度
var uniformity = CalculateColorUniformity(src, rect);

if (uniformity > _confidenceThreshold)
                {
                    results.Add(new DetectionResult
                    {
                        BoundingBox = rect.ToRectangle(),
                        Confidence = uniformity,
                        DetectionMethod = "Color"
                    });
                }
            }
        }

return results;
    }
3.边缘检测

private List<DetectionResult> DetectByEdges(OpenCvSharp.Mat src)
    {
var results = new List<DetectionResult>();

using (var gray = new OpenCvSharp.Mat())
using (var edges = new OpenCvSharp.Mat())
        {
            Cv2.CvtColor(src, gray, ColorConversionCodes.BGR2GRAY);

// 降噪
            Cv2.GaussianBlur(gray, gray, new OpenCvSharp.Size(5, 5), 1.5);

// 边缘检测
            Cv2.Canny(gray, edges, 50, 150);

// 膨胀
var kernel = Cv2.GetStructuringElement(MorphShapes.Rect, new OpenCvSharp.Size(3, 3));
            Cv2.Dilate(edges, edges, kernel, iterations: 2);

// 查找轮廓
            Cv2.FindContours(edges, outvar contours, outvar hierarchy,
                RetrievalModes.External, ContourApproximationModes.ApproxSimple);

foreach (var contour in contours)
            {
var area = Cv2.ContourArea(contour);

if (area < _minArea || area > _maxArea)
continue;

var rect = Cv2.BoundingRect(contour);

// 计算边缘密度
using (var roi = new OpenCvSharp.Mat(edges, rect))
                {
var totalPixels = roi.Rows * roi.Cols;
var edgePixels = Cv2.CountNonZero(roi);
var edgeDensity = (double)edgePixels / totalPixels;

if (edgeDensity > 0.1 && rect.Width > 100 && rect.Height > 100)
                    {
                        results.Add(new DetectionResult
                        {
                            BoundingBox = rect.ToRectangle(),
                            Confidence = edgeDensity,
                            DetectionMethod = "Edge"
                        });
                    }
                }
            }
        }

return results;
    }

方式二:通过OCR识别面单内容,根据所有切割点坐标点最小外界矩形来定位面单位置

OCR基础模型用的是SVTR-LCNet这个架构的网络模型，论文是公开的，我们在这个基础上做的复现与调优。话不多说，先看效果

相机拍照原始包裹图片

OCR识别切割效果(根据识别文字角度自动校正)

定位到每个识别内容的矩形坐标，获取所有当前图片所有切割矩形的最小外接矩形，然后裁切，就可以得到包含所有面单内容的图片

抠面单效果(实际会比面单小，但是满足客户需求，包含了所有面单内容)

废话不多说，附上代码

复制代码

///<summary>
/// 返回面单图片
///</summary>
///<param name="errorMsg">异常信息</param>
///<param name="IsEnhanceImage">面单是否增强</param>
///<param name="IsSaveLocl">是否本地保存</param>
///<returns></returns>
public Bitmap GetLabelImageByBitmap(outstring errorMsg, bool IsEnhanceImage = true, bool IsSaveLocl = true)
 {
     Bitmap croppedImage = null;
     errorMsg = string.Empty;
     try
     {
         if (!File.Exists(imagePath))
         {
             ShellLine.WriteLine($"请确保 {imagePath} 存在");
             errorMsg = $"请确保 {imagePath} 存在";
             returnnew Bitmap(10, 10);
         }
         //图片目录
         string imageDir = Path.GetDirectoryName(debugImagePath);
         if (Directory.Exists(imageDir))
         {
             Directory.CreateDirectory(imageDir);
         }
         Bitmap bitmap1 = new Bitmap(imagePath);
         var rr = oCR.GetOCRDataStr(bitmap1, debugImagePath);

         // 读取JSON文件
         string jsonFilePath = imageDir + "\\content.json";

         if (!File.Exists(jsonFilePath))
         {
             errorMsg = $"未找到JSON文件，请确保 {jsonFilePath} 存在";
             ShellLine.WriteLine($"未找到JSON文件，请确保 {jsonFilePath} 存在");
             returnnew Bitmap(imagePath);
         }

         string preRotatedImage = imageDir + "\\preRotatedImg.jpg";
         if (!File.Exists(preRotatedImage))
         {
             errorMsg = $"未找到面单文件，请确保包裹面单清晰且存在";
             ShellLine.WriteLine($"未找到面单文件，请确保包裹面单清晰且存在");
             returnnew Bitmap(imagePath);
         }

         // 解析矩形数据并计算最小外接矩形
         List<Rectangle> rectangles = ParseRectanglesFromJson(jsonFilePath);
         if (rectangles.Count == 0)
         {
             errorMsg = "未在JSON文件中找到有效的矩形数据";
             ShellLine.WriteLine("未在JSON文件中找到有效的矩形数据");
             returnnew Bitmap(imagePath);
         }

         Rectangle boundingRect = CalculateBoundingRectangle(rectangles);
         ShellLine.WriteLine($"最小外接矩形: X={boundingRect.X}, Y={boundingRect.Y}, Width={boundingRect.Width}, Height={boundingRect.Height}");
         ShellLine.WriteLine($"包含 {rectangles.Count} 个元素");

         // 加载图片并进行裁剪
         using (Bitmap originalImage = new Bitmap(preRotatedImage))
         {
             // 确保矩形在图片范围内
             Rectangle safeRect = GetSafeRectangle(boundingRect, originalImage);
             // 裁剪图片
             croppedImage = CropImage(originalImage, safeRect);
             if (IsEnhanceImage)
             {
                 // 增强显示 
                 EnhanceImage(ref croppedImage);
             }
             if (IsSaveLocl)
             {
                 // 保存结果
                 string outputPath = Path.Combine(
                     Path.GetDirectoryName(preRotatedImage),
                     Path.GetFileNameWithoutExtension(preRotatedImage) + "_cropped_enhanced.jpg");

                 croppedImage.Save(outputPath, ImageFormat.Jpeg);
                 ShellLine.WriteLine($"处理完成！结果已保存到: {outputPath}");
             }
             // 显示裁剪区域信息
             ShellLine.WriteLine($"\n裁剪区域信息:");
             ShellLine.WriteLine($"  原始图片尺寸: {originalImage.Width}x{originalImage.Height}");
             ShellLine.WriteLine($"  裁剪区域: {safeRect.X}, {safeRect.Y}, {safeRect.Width}x{safeRect.Height}");
             ShellLine.WriteLine($"  增强后图片尺寸: {croppedImage.Width}x{croppedImage.Height}");
             return croppedImage;
         }
     }
     catch (Exception ex)
     {
         errorMsg = $"处理过程中出现错误: {ex.Message}";
         ShellLine.WriteLine($"处理过程中出现错误: {ex.Message}");
         ShellLine.WriteLine($"堆栈跟踪: {ex.StackTrace}");
         returnnew Bitmap(imagePath);
     }
     finally
     {
         // 释放资源
         croppedImage?.Dispose();
     }
 }

图片增强显示，有需要可以调用

复制代码

///<summary>
/// 图片增强显示
///</summary>
///<param name="image"></param>
publicvoidEnhanceImage(ref Bitmap image)
 {
     using (var mat = image.ToMat())
     using (var lab = new OpenCvSharp.Mat())
     {
         // 转换为Lab色彩空间
         Cv2.CvtColor(mat, lab, ColorConversionCodes.BGR2Lab);

         Cv2.Split(lab, outvar labChannels);

         // 对亮度通道进行直方图均衡化
         Cv2.EqualizeHist(labChannels[0], labChannels[0]);

         Cv2.Merge(labChannels, lab);
         Cv2.CvtColor(lab, mat, ColorConversionCodes.Lab2BGR);

         // 释放通道
         foreach (var channel in labChannels)
             channel.Dispose();

         // 更新图像
         image.Dispose();
         image = mat.ToBitmap();
     }
 }

获取包含所有切割字符的最小外接矩形

复制代码

// 计算包含所有矩形的最小外接矩形
  static Rectangle CalculateBoundingRectangle(List<Rectangle> rectangles)
  {
      if (rectangles.Count == 0)
          thrownew ArgumentException("矩形列表为空");

      int minX = int.MaxValue;
      int minY = int.MaxValue;
      int maxX = int.MinValue;
      int maxY = int.MinValue;

      foreach (Rectangle rect in rectangles)
      {
          minX = Math.Min(minX, rect.X);
          minY = Math.Min(minY, rect.Y);
          maxX = Math.Max(maxX, rect.X + rect.Width);
          maxY = Math.Max(maxY, rect.Y + rect.Height);
      }

      // 添加一些边距，使裁剪更美观
      int margin = 10;
      minX = Math.Max(0, minX - margin);
      minY = Math.Max(0, minY - margin);
      maxX = maxX + margin;
      maxY = maxY + margin;

      returnnew Rectangle(minX, minY, maxX - minX, maxY - minY);
  }

// 确保矩形在图片范围内
static Rectangle GetSafeRectangle(Rectangle rect, Bitmap image)
  {
      int x = Math.Max(0, Math.Min(rect.X, image.Width - 1));
      int y = Math.Max(0, Math.Min(rect.Y, image.Height - 1));
      int width = Math.Min(rect.Width, image.Width - x);
      int height = Math.Min(rect.Height, image.Height - y);

      returnnew Rectangle(x, y, width, height);
  }

// 裁剪图片
static Bitmap CropImage(Bitmap source, Rectangle cropArea)
  {
      Bitmap target = new Bitmap(cropArea.Width, cropArea.Height);

      using (Graphics g = Graphics.FromImage(target))
      {
          g.DrawImage(source, new Rectangle(0, 0, cropArea.Width, cropArea.Height),
              cropArea, GraphicsUnit.Pixel);
      }
      return target;
  }

**　　结束语**

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