■ 자동차 번호판을 인식하는 방법을 보여준다.
▶ LicensePlateDetector.cs
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using System; using System.Collections.Generic; using System.Drawing; using System.Text; using Emgu.CV; using Emgu.CV.CvEnum; using Emgu.CV.OCR; using Emgu.CV.Structure; using Emgu.Util; namespace TestProject { /// <summary> /// 자동차 번호판 검출기 /// </summary> public class LicensePlateDetector : DisposableObject { //////////////////////////////////////////////////////////////////////////////////////////////////// Field ////////////////////////////////////////////////////////////////////////////////////////// Private #region Field /// <summary> /// OCR /// </summary> private Tesseract ocr; #endregion //////////////////////////////////////////////////////////////////////////////////////////////////// Constructor ////////////////////////////////////////////////////////////////////////////////////////// Public #region 생성자 - LicensePlateDetector(dataPath) /// <summary> /// 생성자 /// </summary> /// <param name="dataPath">데이터 경로</param> public LicensePlateDetector(string dataPath) { this.ocr = new Tesseract(dataPath, "eng", Tesseract.OcrEngineMode.OEM_TESSERACT_CUBE_COMBINED); this.ocr.SetVariable("tessedit_char_whitelist", "ABCDEFGHIJKLMNOPQRSTUVWXYZ-1234567890"); } #endregion //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Public #region 자동차 번호판 검출하기 - DetectLicensePlate(sourceImage, licensePlateImageList, filteredLicensePlateImageList, detectedLicensePlateRectangleList) /// <summary> /// 자동차 번호판 검출하기 /// </summary> /// <param name="sourceImage">소스 이미지</param> /// <param name="licensePlateImageList">자동차 번호판 이미지 리스트</param> /// <param name="filteredLicensePlateImageList">필터 자동차 번호판 이미지 리스트</param> /// <param name="detectedLicensePlateRectangleList">검출 자동차 번호판 사각형 리스트</param> /// <returns>자동차 번호 리스트</returns> public List<string> DetectLicensePlate ( Image<Bgr, byte> sourceImage, List<Image<Gray, Byte>> licensePlateImageList, List<Image<Gray, Byte>> filteredLicensePlateImageList, List<MCvBox2D> detectedLicensePlateRectangleList) { List<string> licenseList = new List<String>(); using(Image<Gray, byte> grayscaleImage = sourceImage.Convert<Gray, Byte>()) { using(Image<Gray, Byte> cannyImage = new Image<Gray, byte>(grayscaleImage.Size)) { using(MemStorage storage = new MemStorage()) { CvInvoke.cvCanny(grayscaleImage, cannyImage, 100, 50, 3); Contour<Point> pointContour = cannyImage.FindContours ( CHAIN_APPROX_METHOD.CV_CHAIN_APPROX_SIMPLE, RETR_TYPE.CV_RETR_TREE, storage ); FindLicensePlate ( pointContour, grayscaleImage, cannyImage, licensePlateImageList, filteredLicensePlateImageList, detectedLicensePlateRectangleList, licenseList ); } } } return licenseList; } #endregion ////////////////////////////////////////////////////////////////////////////////////////// Public #region 흰색 픽셀 마스크 구하기 - GetWhitePixelMask(image) /// <summary> /// 흰색 픽셀 마스크 구하기 /// </summary> /// <param name="image">이미지</param> /// <returns>흰색 픽셀 마스크</returns> /// <remarks> /// 흰색 픽셀은 채도가 40보다 작거나 200보다 큰 경우에 해당한다. /// </remarks> private static Image<Gray, Byte> GetWhitePixelMask(Image<Bgr, byte> image) { using(Image<Hsv, Byte> hsvImage = image.Convert<Hsv, Byte>()) { Image<Gray, Byte>[] grayscaleImageArray = hsvImage.Split(); try { grayscaleImageArray[1]._ThresholdBinaryInv(new Gray(40), new Gray(255)); grayscaleImageArray[2]._ThresholdBinary(new Gray(200), new Gray(255)); CvInvoke.cvAnd(grayscaleImageArray[1], grayscaleImageArray[2], grayscaleImageArray[0], IntPtr.Zero); } finally { grayscaleImageArray[1].Dispose(); grayscaleImageArray[2].Dispose(); } return grayscaleImageArray[0]; } } #endregion #region 자식 카운트 구하기 - GetChildCount(contour) /// <summary> /// 자식 카운트 구하기 /// </summary> /// <param name="contour">윤곽</param> /// <returns>자식 카운트</returns> private static int GetChildCount(Contour<Point> contour) { Contour<Point> childContour = contour.VNext; if(childContour == null) { return 0; } int count = 0; while(childContour != null) { count++; childContour = childContour.HNext; } return count; } #endregion #region 자동차 번호판 찾기 - FindLicensePlate(pointContour, grayscaleImage, cannyImage, licensePlateImageList, filteredLicensePlateImageList, detectedLicensePlateRectangleList, licenseList) /// <summary> /// 자동차 번호판 찾기 /// </summary> /// <param name="pointContour">포인트 윤곽</param> /// <param name="grayscaleImage">회색조 이미지</param> /// <param name="cannyImage">캐니 이미지</param> /// <param name="licensePlateImageList">자동차 번호판 이미지 리스트</param> /// <param name="filteredLicensePlateImageList">필터 자동차 번호판 이미지 리스트</param> /// <param name="detectedLicensePlateRectangleList">검출 자동차 번호판 사각형 리스트</param> /// <param name="licenseList">자동차 번호 리스트</param> private void FindLicensePlate ( Contour<Point> pointContour, Image<Gray, Byte> grayscaleImage, Image<Gray, Byte> cannyImage, List<Image<Gray, Byte>> licensePlateImageList, List<Image<Gray, Byte>> filteredLicensePlateImageList, List<MCvBox2D> detectedLicensePlateRectangleList, List<String> licenseList ) { for(; pointContour != null; pointContour = pointContour.HNext) { int childCount = GetChildCount(pointContour); if(childCount == 0) { continue; } if(pointContour.Area > 400) { if(childCount < 3) { // 윤곽선에 자식 윤곽선이 3개 보다 작은 경우는 자동차 번호판이 아니디. // (자동차 번호판에 문자가 3자 이상 있다고 가정한다) // 그러나 윤곽선의 자식 윤곽선을 검색해 그 중 하나가 자동차 번호판인지 확인해야 한다. FindLicensePlate ( pointContour.VNext, grayscaleImage, cannyImage, licensePlateImageList, filteredLicensePlateImageList, detectedLicensePlateRectangleList, licenseList ); continue; } MCvBox2D rectangle = pointContour.GetMinAreaRect(); if(rectangle.angle < -45.0) { float temporaryWidth = rectangle.size.Width; rectangle.size.Width = rectangle.size.Height; rectangle.size.Height = temporaryWidth; rectangle.angle += 90.0f; } else if(rectangle.angle > 45.0) { float temporaryWidth = rectangle.size.Width; rectangle.size.Width = rectangle.size.Height; rectangle.size.Height = temporaryWidth; rectangle.angle -= 90.0f; } double ratio = (double)rectangle.size.Width / rectangle.size.Height; if(!(3.0 < ratio && ratio < 10.0)) { Contour<Point> childContour = pointContour.VNext; if(childContour != null) { FindLicensePlate ( childContour, grayscaleImage, cannyImage, licensePlateImageList, filteredLicensePlateImageList, detectedLicensePlateRectangleList, licenseList ); } continue; } using(Image<Gray, Byte> temporaryImage1 = grayscaleImage.Copy(rectangle)) { using(Image<Gray, Byte> temporaryImage2 = temporaryImage1.Resize(240, 180, INTER.CV_INTER_CUBIC, true)) { int edgePixelSize = 2; temporaryImage2.ROI = new Rectangle ( new Point(edgePixelSize, edgePixelSize), temporaryImage2.Size - new Size(2 * edgePixelSize, 2 * edgePixelSize) ); Image<Gray, Byte> plateImage = temporaryImage2.Copy(); Image<Gray, Byte> filteredPlateImage = FilterLicensePlateImage(plateImage); Tesseract.Charactor[] charactorArray; StringBuilder stringBuilder = new StringBuilder(); using(Image<Gray, Byte> temporaryImage3 = filteredPlateImage.Clone()) { this.ocr.Recognize(temporaryImage3); charactorArray = this.ocr.GetCharactors(); if(charactorArray.Length == 0) { continue; } for(int i = 0; i < charactorArray.Length; i++) { stringBuilder.Append(charactorArray[i].Text); } } licenseList.Add(stringBuilder.ToString()); licensePlateImageList.Add(plateImage); filteredLicensePlateImageList.Add(filteredPlateImage); detectedLicensePlateRectangleList.Add(rectangle); } } } } } #endregion #region 자동차 번호판 이미지 필터하기 - FilterLicensePlateImage(sourceImage) /// <summary> /// 자동차 번호판 이미지 필터하기 /// </summary> /// <param name="sourceImage">소스 이미지</param> /// <returns>필터 이미지</returns> private static Image<Gray, Byte> FilterLicensePlateImage(Image<Gray, Byte> sourceImage) { Image<Gray, Byte> threshImage = sourceImage.ThresholdBinaryInv(new Gray(120), new Gray(255)); using(Image<Gray, Byte> maskImage = new Image<Gray, byte>(sourceImage.Size)) { using(Image<Gray, Byte> cannyImage = sourceImage.Canny(100, 50)) { using(MemStorage storage = new MemStorage()) { maskImage.SetValue(255.0); for(Contour<Point> pointContour = cannyImage.FindContours(CHAIN_APPROX_METHOD.CV_CHAIN_APPROX_SIMPLE, RETR_TYPE.CV_RETR_EXTERNAL, storage); pointContour != null; pointContour = pointContour.HNext) { Rectangle rectangle = pointContour.BoundingRectangle; if(rectangle.Height > (sourceImage.Height >> 1)) { rectangle.X -= 1; rectangle.Y -= 1; rectangle.Width += 2; rectangle.Height += 2; rectangle.Intersect(sourceImage.ROI); maskImage.Draw(rectangle, new Gray(0.0), -1); } } threshImage.SetValue(0, maskImage); } } } threshImage._Erode(1); threshImage._Dilate(1); return threshImage; } #endregion #region 객체 리소스 해제하기 - DisposeObject() /// <summary> /// 객체 리소스 해제하기 /// </summary> protected override void DisposeObject() { this.ocr.Dispose(); } #endregion } } |
▶ MainForm.cs
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using System; using System.Collections.Generic; using System.Diagnostics; using System.Drawing; using System.Windows.Forms; using Emgu.CV; using Emgu.CV.Structure; using Emgu.CV.UI; namespace TestProject { /// <summary> /// 메인 폼 /// </summary> public partial class MainForm : Form { //////////////////////////////////////////////////////////////////////////////////////////////////// Field ////////////////////////////////////////////////////////////////////////////////////////// Private #region Field /// <summary> /// 번호판 검출기 /// </summary> private LicensePlateDetector licensePlateDetector; #endregion //////////////////////////////////////////////////////////////////////////////////////////////////// Constructor ////////////////////////////////////////////////////////////////////////////////////////// Public #region 생성자 - MainForm() /// <summary> /// 생성자 /// </summary> public MainForm() { InitializeComponent(); this.filePathButton.Click += filePathButton_Click; this.licensePlateDetector = new LicensePlateDetector(""); ProcessImage(new Image<Bgr, byte>("LicensePlate.jpg")); } #endregion //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Private //////////////////////////////////////////////////////////////////////////////// Event #region 파일 경로 버튼 클릭시 처리하기 - filePathButton_Click(sender, e) /// <summary> /// 파일 경로 버튼 클릭시 처리하기 /// </summary> /// <param name="sender">이벤트 발생자</param> /// <param name="e">이벤트 인자</param> private void filePathButton_Click(object sender, EventArgs e) { DialogResult result = this.openFileDialog.ShowDialog(); if(result == DialogResult.OK) { Image<Bgr, Byte> image; try { image = new Image<Bgr, byte>(this.openFileDialog.FileName); } catch { MessageBox.Show(string.Format("무효한 파일 : {0}", this.openFileDialog.FileName)); return; } ProcessImage(image); } } #endregion //////////////////////////////////////////////////////////////////////////////// Function #region 레이블/이미지 추가하기 - AddLabelAndImage(startPoint, labelText, image) /// <summary> /// 레이블/이미지 추가하기 /// </summary> /// <param name="startPoint">시작 위치</param> /// <param name="labelText">레이블 텍스트</param> /// <param name="image">이미지</param> private void AddLabelAndImage(ref Point startPoint, string labelText, IImage image) { Label label = new Label(); this.resultPanel.Controls.Add(label); label.Width = 200; label.Height = 30; label.Location = startPoint; label.Text = labelText; startPoint.Y += label.Height; ImageBox imageBox = new ImageBox(); this.resultPanel.Controls.Add(imageBox); imageBox.ClientSize = image.Size; imageBox.Location = startPoint; imageBox.Image = image; startPoint.Y += imageBox.Height + 10; } #endregion #region 이미지 처리하기 - ProcessImage(image) /// <summary> /// 이미지 처리하기 /// </summary> /// <param name="image">이미지</param> private void ProcessImage(Image<Bgr, byte> image) { Stopwatch stopwatch = Stopwatch.StartNew(); List<Image<Gray, Byte>> licensePlateImageList = new List<Image<Gray, byte>>(); List<Image<Gray, Byte>> filteredLicensePlateImageList = new List<Image<Gray, byte>>(); List<MCvBox2D> licenseRectangleList = new List<MCvBox2D>(); List<string> licensePlateArray = this.licensePlateDetector.DetectLicensePlate ( image, licensePlateImageList, filteredLicensePlateImageList, licenseRectangleList ); stopwatch.Stop(); this.messageLabel.Text = string.Format("자동차 번호판 인식 시간 : {0} 밀리초", stopwatch.Elapsed.TotalMilliseconds); this.resultPanel.Controls.Clear(); Point startPoint = new Point(10, 10); for(int i = 0; i < licensePlateArray.Count; i++) { AddLabelAndImage ( ref startPoint, string.Format("자동차 번호 : {0}", licensePlateArray[i]), licensePlateImageList[i].ConcateVertical(filteredLicensePlateImageList[i]) ); image.Draw(licenseRectangleList[i], new Bgr(Color.Red), 2); } this.imageBox.Image = image; } #endregion } } |
