using System;
using System.IO;
using System.Drawing;namespace SimilarPhoto
{class SimilarPhoto{Image SourceImg;public SimilarPhoto(string filePath){SourceImg = Image.FromFile(filePath);}public SimilarPhoto(Stream stream){SourceImg = Image.FromStream(stream);}public String GetHash(){Image image = ReduceSize();Byte[] grayValues = ReduceColor(image);Byte average = CalcAverage(grayValues);String reslut = ComputeBits(grayValues, average);return reslut;}// Step 1 : Reduce size to 8*8private Image ReduceSize(int width = 8, int height = 8){Image image = SourceImg.GetThumbnailImage(width, height, () => { return false; }, IntPtr.Zero);return image;}// Step 2 : Reduce Colorprivate Byte[] ReduceColor(Image image){Bitmap bitMap = new Bitmap(image);Byte[] grayValues = new Byte[image.Width * image.Height];for(int x = 0; x<image.Width; x++)for (int y = 0; y < image.Height; y++){Color color = bitMap.GetPixel(x, y);byte grayValue = (byte)((color.R * 30 + color.G * 59 + color.B * 11) / 100);grayValues[x * image.Width + y] = grayValue;}return grayValues;}// Step 3 : Average the colorsprivate Byte CalcAverage(byte[] values){int sum = 0;for (int i = 0; i < values.Length; i++)sum += (int)values[i];return Convert.ToByte(sum / values.Length);}// Step 4 : Compute the bitsprivate String ComputeBits(byte[] values, byte averageValue){char[] result = new char[values.Length];for (int i = 0; i < values.Length; i++){if (values[i] < averageValue)result[i] = '0';elseresult[i] = '1';}return new String(result);}// Compare hashpublic static Int32 CalcSimilarDegree(string a, string b){if (a.Length != b.Length)throw new ArgumentException();int count = 0;for (int i = 0; i < a.Length; i++){if (a[i] != b[i])count++;}return count;}}
}