[C#/WINFORM] 가우시안 커널(Gaussian Kernel) 계산하기

TestProject.zip

다운로드

▶ BitmapHelper.cs

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 가우시안 커널 계산하기 - CalculateGaussianKernel(length, weight)

        /// <summary>
        /// 가우시안 커널 계산하기
        /// </summary>
        /// <param name="length">길이</param>
        /// <param name="weight">가중치</param>
        /// <returns>가우시안 커널 배열</returns>
        public static double[,] CalculateGaussianKernel(int length, double weight)
        {
            double[,] filterArray     = new double [length, length];
            double    totalSummary    = 0;
            int       kernelRadius    = length / 2;
            double    distance        = 0;
            double    eulerCalculated = 1.0 / (2.0 * Math.PI * Math.Pow(weight, 2));

            for(int filterY = -kernelRadius; filterY <= kernelRadius; filterY++)
            {
                for(int filterX = -kernelRadius; filterX <= kernelRadius; filterX++)
                {
                    distance = ((filterX * filterX) + (filterY * filterY)) / (2 * (weight * weight));

                    filterArray[filterY + kernelRadius, filterX + kernelRadius] = eulerCalculated * Math.Exp(-distance);

                    totalSummary += filterArray[filterY + kernelRadius, filterX + kernelRadius];
                }
            }

            for(int y = 0; y < length; y++)
            {
                for(int x = 0; x < length; x++)
                {
                    filterArray[y, x] = filterArray[y, x] * (1.0 / totalSummary);
                }
            }

            return filterArray;
        }

        #endregion
        #region 회선 필터 적용하기 - ApplyConvolutionFilter(sourceBitmap, filterArray, factor, bias)

        /// <summary>
        /// 회선 필터 적용하기
        /// </summary>
        /// <param name="sourceBitmap">소스 비트맵</param>
        /// <param name="filterArray">필터 배열</param>
        /// <param name="factor">인자</param>
        /// <param name="bias">바이어스</param>
        /// <returns>비트맵</returns>
        public static Bitmap ApplyConvolutionFilter(Bitmap sourceBitmap, double[,] filterArray, double factor = 1, int bias = 0)
        {
            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);

            double blue  = 0.0;
            double green = 0.0;
            double red   = 0.0;

            int filterWidth  = filterArray.GetLength(1);
            int filterHeight = filterArray.GetLength(0);
            int filterOffset = (filterWidth - 1) / 2;
            int sourceOffset = 0;
            int targetOffset = 0;

            for(int offsetY = filterOffset; offsetY < sourceBitmap.Height - filterOffset; offsetY++)
            {
                for(int offsetX = filterOffset; offsetX < sourceBitmap.Width - filterOffset; offsetX++)
                {
                    blue  = 0;
                    green = 0;
                    red   = 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);

                            blue += (double)(sourceByteArray[sourceOffset]) * 
                                    filterArray[filterY + filterOffset, filterX + filterOffset];

                            green += (double)(sourceByteArray[sourceOffset + 1]) *
                                        filterArray[filterY + filterOffset, filterX + filterOffset];

                            red += (double)(sourceByteArray[sourceOffset + 2]) *
                                    filterArray[filterY + filterOffset, filterX + filterOffset];
                        }
                    }

                    blue  = factor * blue + bias;
                    green = factor * green + bias;
                    red   = factor * red + bias;

                    blue  = (blue  > 255 ? 255 : (blue  < 0 ? 0 : blue ));
                    green = (green > 255 ? 255 : (green < 0 ? 0 : green));
                    red   = (red   > 255 ? 255 : (red   < 0 ? 0 : red  ));

                    targetByteArray[targetOffset    ] = (byte)(blue);
                    targetByteArray[targetOffset + 1] = (byte)(green);
                    targetByteArray[targetOffset + 2] = (byte)(red);
                    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
    }  
}

 

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▶ MainForm.cs

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();

            double[,] kernelArray  = BitmapHelper.CalculateGaussianKernel(5, 5.5);
            Bitmap    sourceBitmap = BitmapHelper.LoadBitmap("IMAGE\\sample.jpg");
            Bitmap    targetBitmap = BitmapHelper.ApplyConvolutionFilter(sourceBitmap, kernelArray, 1, 0);

            this.pictureBox.SizeMode = PictureBoxSizeMode.Zoom;
            this.pictureBox.Image    = targetBitmap;
        }

        #endregion
    }
}