예제 #1
0
        /// <summary>
        /// Compare two image hashes and return a value between 0 and 1.
        /// 0 meaning the two hashes (and therefore underlying images) are the same,
        /// and 1 meaning they are totally different.
        /// </summary>
        /// <param name="hash1"></param>
        /// <param name="hash2"></param>
        /// <returns></returns>
        public static double CompareHashes(ImageHash hash1, ImageHash hash2)
        {
            if (hash1.Algorithm != hash2.Algorithm)
            {
                throw new ArgumentException("Both hashes must use the same algorithm!");
            }
            double result;
            switch (hash1.Algorithm)
            {
                case HashAlgorithm.DCT:
                    int rawHammingResult =
                        NativeFunctions.ph_hamming_distance(((DCTHash)hash1).Hash, ((DCTHash)hash2).Hash);
                    result = NormalizeThreshold(HashAlgorithm.DCT, rawHammingResult);
                    break;
                case HashAlgorithm.Radial:
                    NativeStructures.Digest digest1 = ((RadialHash)hash1).Digest;
                    NativeStructures.Digest digest2 = ((RadialHash)hash2).Digest;

                    double rawCrossCorrResult;
                    NativeFunctions.ph_crosscorr(ref digest1, ref digest2, out rawCrossCorrResult);
                    result = NormalizeThreshold(HashAlgorithm.Radial, rawCrossCorrResult);
                    break;
                case HashAlgorithm.MH:
                    MHHash mhHash1 = (MHHash)hash1;
                    MHHash mhHash2 = (MHHash)hash2;

                    double rawHamming2Result =
                        NativeFunctions.ph_hammingdistance2(mhHash1.BytesPtr, mhHash1.ByteCount, mhHash2.BytesPtr, mhHash2.ByteCount);
                    result = NormalizeThreshold(HashAlgorithm.MH, rawHamming2Result);
                    break;
                default:
                    throw new NotImplementedException();
            }
            return result;
        }
예제 #2
0
        /// <summary>
        /// Compare two image hashes and return a value between 0 and 1.
        /// 0 meaning the two hashes (and therefore underlying images) are the same,
        /// and 1 meaning they are totally different.
        /// </summary>
        /// <param name="hash1"></param>
        /// <param name="hash2"></param>
        /// <returns></returns>
        public static double CompareHashes(ImageHash hash1, ImageHash hash2)
        {
            if (hash1.Algorithm != hash2.Algorithm)
            {
                throw new ArgumentException("Both hashes must use the same algorithm!");
            }
            double result;

            switch (hash1.Algorithm)
            {
            case HashAlgorithm.DCT:
                int rawHammingResult =
                    NativeFunctions.ph_hamming_distance(((DCTHash)hash1).Hash, ((DCTHash)hash2).Hash);
                result = NormalizeThreshold(HashAlgorithm.DCT, rawHammingResult);
                break;

            case HashAlgorithm.Radial:
                NativeStructures.Digest digest1 = ((RadialHash)hash1).Digest;
                NativeStructures.Digest digest2 = ((RadialHash)hash2).Digest;

                double rawCrossCorrResult;
                NativeFunctions.ph_crosscorr(ref digest1, ref digest2, out rawCrossCorrResult);
                result = NormalizeThreshold(HashAlgorithm.Radial, rawCrossCorrResult);
                break;

            case HashAlgorithm.MH:
                MHHash mhHash1 = (MHHash)hash1;
                MHHash mhHash2 = (MHHash)hash2;

                double rawHamming2Result =
                    NativeFunctions.ph_hammingdistance2(mhHash1.BytesPtr, mhHash1.ByteCount, mhHash2.BytesPtr, mhHash2.ByteCount);
                result = NormalizeThreshold(HashAlgorithm.MH, rawHamming2Result);
                break;

            default:
                throw new NotImplementedException();
            }
            return(result);
        }
예제 #3
0
 /// <summary>
 /// Compare two image hashes and return a boolean indicating if the underlying images are similar (true) or not (false).
 /// </summary>
 /// <param name="hash1"></param>
 /// <param name="hash2"></param>
 /// <param name="result"></param>
 /// <param name="threshold"></param>
 /// <returns></returns>
 public static bool CompareHashes(ImageHash hash1, ImageHash hash2, out double result, double threshold = .40f)
 {
     result = CompareHashes(hash1, hash2);
     return result <= threshold;
 }
예제 #4
0
        /// <summary>
        /// Compare two image hashes and return a boolean indicating if the underlying images are similar (true) or not (false).
        /// </summary>
        /// <param name="hash1"></param>
        /// <param name="hash2"></param>
        /// <param name="threshold"></param>
        /// <returns></returns>
        public static bool CompareHashes(ImageHash hash1, ImageHash hash2, double threshold = .40f)
        {
            double result = CompareHashes(hash1, hash2);

            return(result <= threshold);
        }