WPF：图像处理（三）二值化

[csharp]

文件名称：Binarize.cs
 
开发环境：
    Visual Studio V2010
    .NET Framework 4 Client Profile
 
版本历史：
    V1.1    2012年04月17日
            实现迭代法阈值计算方法
 
    V1.0    2012年04月16日
            实现大津法阈值计算方法
------------------------------------------------------------ */ 
using System; 
using System.Windows.Media; 
using System.Windows.Media.Imaging; 
 
namespace Splash.Imaging 
{ 
    /// <summary> 
    /// 二值化方法 
    /// </summary> 
    public enum BinarizationMethods 
    {         
        Otsu,       // 大津法 
        Iterative   // 迭代法 
    } 
 
    /// <summary> 
    /// 图像处理：图像二值化 
    /// </summary> 
    public static partial class Binarize 
    {       
        /// <summary> 
        /// 全局阈值图像二值化 
        /// </summary> 
        /// <param name="bitmap">原始图像</param> 
        /// <param name="method">二值化方法</param> 
        /// <param name="threshold">输出：全局阈值</param> 
        /// <returns>二值化后的图像数组</returns>         
        public static Byte[,] ToBinaryArray(this BitmapSource bitmap, BinarizationMethods method, out Int32 threshold) 
        {   // 位图转换为灰度数组 
            Byte[,] GrayArray = bitmap.ToGrayArray(); 
             
            // 计算全局阈值 
            if (method == BinarizationMethods.Otsu) 
                threshold = OtsuThreshold(GrayArray); 
            else 
                threshold = IterativeThreshold(GrayArray); 
 
            // 根据阈值进行二值化 www.2cto.com  
            Int32 PixelHeight = bitmap.PixelHeight; 
            Int32 PixelWidth = bitmap.PixelWidth; 
            Byte[,] BinaryArray = new Byte[PixelHeight, PixelWidth]; 
            for (Int32 i = 0; i < PixelHeight; i++) 
            { 
                for (Int32 j = 0; j < PixelWidth; j++) 
                { 
                    BinaryArray[i,j] = Convert.ToByte((GrayArray[i,j] > threshold) ? 255 : 0); 
                } 
            } 
 
            return BinaryArray; 
        } 
 
        /// <summary> 
        /// 全局阈值图像二值化 
        /// </summary> 
        /// <param name="bitmap">原始图像</param> 
        /// <param name="method">二值化方法</param> 
        /// <param name="threshold">输出：全局阈值</param> 
        /// <returns>二值化图像</returns> 
        public static BitmapSource ToBinaryBitmap(this BitmapSource bitmap, BinarizationMethods method, out Int32 threshold) 
        {   // 位图转换为灰度数组 
            Byte[,] GrayArray = bitmap.ToGrayArray(); 
 
            // 计算全局阈值 
            if (method == BinarizationMethods.Otsu) 
                threshold = OtsuThreshold(GrayArray); 
            else 
                threshold = IterativeThreshold(GrayArray); 
 
            // 将灰度数组转换为二值数据 
            Int32 PixelHeight = bitmap.PixelHeight; 
            Int32 PixelWidth = bitmap.PixelWidth; 
            Int32 Stride = ((PixelWidth + 31) >> 5) << 2; 
            Byte[] Pixels = new Byte[PixelHeight * Stride]; 
            for (Int32 i = 0; i < PixelHeight; i++) 
            { 
                Int32 Base = i * Stride; 
                for (Int32 j = 0; j < PixelWidth; j++) 
                { 
                    if (GrayArray[i, j] > threshold) 
                    { 
                        Pixels[Base + (j >> 3)] |= Convert.ToByte(0x80 >> (j & 0x7)); 
                    } 
                } 
            } 
 
            // 从灰度数据中创建灰度图像 
            return BitmapSource.Create(PixelWidth, PixelHeight, 96, 96, PixelFormats.Indexed1, BitmapPalettes.BlackAndWhite, Pixels, Stride); 
        } 
    } 
} 

作者：秦建辉