■ Bitmap 클래스에서 프리윗 3X3 가장자리 탐지 필터(Prewitt 3X3 Edge Detection Filter)를 사용하는 방법을 보여준다.
▶ Matrix.cs
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namespace TestProject { /// <summary> /// 매트릭스 /// </summary> public static class Matrix { //////////////////////////////////////////////////////////////////////////////////////////////////// Property ////////////////////////////////////////////////////////////////////////////////////////// Static //////////////////////////////////////////////////////////////////////////////// Public #region Prewitt 3X3 Horizontal - Prewitt3X3Horizontal /// <summary> /// Prewitt 3X3 Horizontal /// </summary> public static double[,] Prewitt3X3Horizontal { get { return new double[,] { { -1, 0, 1 }, { -1, 0, 1 }, { -1, 0, 1 } }; } } #endregion #region Prewitt 3X3 Vertical - Prewitt3X3Vertical /// <summary> /// Prewitt 3X3 Vertical /// </summary> public static double[,] Prewitt3X3Vertical { get { return new double[,] { { 1, 1, 1 }, { 0, 0, 0 }, { -1, -1, -1 } }; } } #endregion } } |
▶ BitmapHelper.cs
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using System; using System.Drawing; using System.Drawing.Imaging; using System.Runtime.InteropServices; namespace TestProject { /// <summary> /// 비트맵 헬퍼 /// </summary> public static class BitmapHelper { //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Static //////////////////////////////////////////////////////////////////////////////// Public #region 비트맵 로드하기 - LoadBitmap(filePath) /// <summary> /// 비트맵 로드하기 /// </summary> /// <param name="filePath">파일 경로</param> /// <returns>비트맵</returns> public static Bitmap LoadBitmap(string filePath) { using(Bitmap bitmap = new Bitmap(filePath)) { return new Bitmap(bitmap); } } #endregion #region 프리윗 3X3 필터 적용하기 - ApplyPrewitt3X3Filter(sourceBitmap, grayscale) /// <summary> /// 프리윗 3X3 필터 적용하기 /// </summary> /// <param name="sourceBitmap">소스 비트맵</param> /// <param name="grayscale">회색조 여부</param> /// <returns>비트맵</returns> public static Bitmap ApplyPrewitt3X3Filter(Bitmap sourceBitmap, bool grayscale = true) { Bitmap targetBitmap = ApplyConvolutionFilter ( sourceBitmap, Matrix.Prewitt3X3Horizontal, Matrix.Prewitt3X3Vertical, 1.0, 0, grayscale ); return targetBitmap; } #endregion //////////////////////////////////////////////////////////////////////////////// Private #region 회선 필터 적용하기 - ApplyConvolutionFilter(sourceBitmap, xFilterArray, yFilterArray, factor, bias, grayscale) /// <summary> /// 회선 필터 적용하기 /// </summary> /// <param name="sourceBitmap">소스 비트맵</param> /// <param name="xFilterArray">X 필터 배열</param> /// <param name="yFilterArray">Y 필터 배열</param> /// <param name="factor">팩터</param> /// <param name="bias">바이어스</param> /// <param name="grayscale">회색조 여부</param> /// <returns>비트맵</returns> private static Bitmap ApplyConvolutionFilter ( Bitmap sourceBitmap, double[,] xFilterArray, double[,] yFilterArray, double factor = 1, int bias = 0, bool grayscale = false ) { BitmapData sourceBitmapData = sourceBitmap.LockBits ( new Rectangle(0, 0, sourceBitmap.Width, sourceBitmap.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb ); byte[] sourceByteArray = new byte[sourceBitmapData.Stride * sourceBitmapData.Height]; byte[] targetByteArray = new byte[sourceBitmapData.Stride * sourceBitmapData.Height]; Marshal.Copy(sourceBitmapData.Scan0, sourceByteArray, 0, sourceByteArray.Length); sourceBitmap.UnlockBits(sourceBitmapData); if(grayscale == true) { float rgb = 0; for(int k = 0; k < sourceByteArray.Length; k += 4) { rgb = sourceByteArray[k ] * 0.11f; rgb += sourceByteArray[k + 1] * 0.59f; rgb += sourceByteArray[k + 2] * 0.3f; sourceByteArray[k ] = (byte)rgb; sourceByteArray[k + 1] = sourceByteArray[k]; sourceByteArray[k + 2] = sourceByteArray[k]; sourceByteArray[k + 3] = 255; } } double blueX = 0.0; double greenX = 0.0; double redX = 0.0; double blueY = 0.0; double greenY = 0.0; double redY = 0.0; double blueTotal = 0.0; double greenTotal = 0.0; double redTotal = 0.0; int filterOffset = 1; int sourceOffset = 0; int targetOffset = 0; for(int offsetY = filterOffset; offsetY < sourceBitmap.Height - filterOffset; offsetY++) { for(int offsetX = filterOffset; offsetX < sourceBitmap.Width - filterOffset; offsetX++) { blueX = greenX = redX = 0; blueY = greenY = redY = 0; blueTotal = greenTotal = redTotal = 0.0; targetOffset = offsetY * sourceBitmapData.Stride + offsetX * 4; for(int filterY = -filterOffset; filterY <= filterOffset; filterY++) { for(int filterX = -filterOffset; filterX <= filterOffset; filterX++) { sourceOffset = targetOffset + (filterX * 4) + (filterY * sourceBitmapData.Stride); blueX += (double)sourceByteArray[sourceOffset ] * xFilterArray[filterY + filterOffset, filterX + filterOffset]; greenX += (double)sourceByteArray[sourceOffset + 1] * xFilterArray[filterY + filterOffset, filterX + filterOffset]; redX += (double)sourceByteArray[sourceOffset + 2] * xFilterArray[filterY + filterOffset, filterX + filterOffset]; blueY += (double)sourceByteArray[sourceOffset ] * yFilterArray[filterY + filterOffset, filterX + filterOffset]; greenY += (double)sourceByteArray[sourceOffset + 1] * yFilterArray[filterY + filterOffset, filterX + filterOffset]; redY += (double)sourceByteArray[sourceOffset + 2] * yFilterArray[filterY + filterOffset, filterX + filterOffset]; } } blueTotal = Math.Sqrt((blueX * blueX ) + (blueY * blueY )); greenTotal = Math.Sqrt((greenX * greenX) + (greenY * greenY)); redTotal = Math.Sqrt((redX * redX ) + (redY * redY )); if(blueTotal > 255) { blueTotal = 255; } else if(blueTotal < 0) { blueTotal = 0; } if(greenTotal > 255) { greenTotal = 255; } else if(greenTotal < 0) { greenTotal = 0; } if(redTotal > 255) { redTotal = 255; } else if(redTotal < 0) { redTotal = 0; } targetByteArray[targetOffset ] = (byte)blueTotal; targetByteArray[targetOffset + 1] = (byte)greenTotal; targetByteArray[targetOffset + 2] = (byte)redTotal; targetByteArray[targetOffset + 3] = 255; } } Bitmap targetBitmap = new Bitmap(sourceBitmap.Width, sourceBitmap.Height); BitmapData targetBitmapData = targetBitmap.LockBits ( new Rectangle(0, 0, targetBitmap.Width, targetBitmap.Height), ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb ); Marshal.Copy(targetByteArray, 0, targetBitmapData.Scan0, targetByteArray.Length); targetBitmap.UnlockBits(targetBitmapData); return targetBitmap; } #endregion } } |
▶ MainForm.cs
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using System.Drawing; using System.Windows.Forms; namespace TestProject { /// <summary> /// 메인 폼 /// </summary> public partial class MainForm : Form { //////////////////////////////////////////////////////////////////////////////////////////////////// Constructor ////////////////////////////////////////////////////////////////////////////////////////// Public #region 생성자 - MainForm() /// <summary> /// 생성자 /// </summary> public MainForm() { InitializeComponent(); Bitmap sourceBitmap = BitmapHelper.LoadBitmap("IMAGE\\sample.jpg"); Bitmap targetBitmap = BitmapHelper.ApplyPrewitt3X3Filter(sourceBitmap); this.pictureBox.SizeMode = PictureBoxSizeMode.Zoom; this.pictureBox.Image = targetBitmap; } #endregion } } |
