An Algorithm-Bug ! (on absolution and clipping)

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1 parent 4a20967b
Showing 6 changed files with 23 additions and 14 deletions Show diff stats
msteg/__init__.pyc
msteg/steganalysis/MPB.py
msteg/steganalysis/MPB.pyc
msteg/steganography/F3.pyc
msteg/steganography/LSB.pyc
res/lopez5.jpg
@@ -7,9 +7,11 @@ import time
 import math
 import numpy as np
-from .. import *
-from ...mjpeg import Jpeg,colorMap
-from ...common import *
+# from .. import *
+import mjpeg
+from msteg import *
+from mjpeg import Jpeg, colorMap
+from common import *
 import csv
 import json
@@ -43,14 +45,14 @@ class MPB(StegBase):
         :param T: signed integer, usually 1~7
         :return: TPM - 3-D tensor, numpy array of size (2*T+1, 2*T+1, 4)
         """
-        ciq = np.absolute(ciq).clip(0, T)
+        ciq = np.absolute(ciq)
         TPM = np.zeros((2 * T + 1, 2 * T + 1, 4), np.float64)
         # Fh = np.diff(ciq, axis=-1)
         # Fv = np.diff(ciq, axis=0)
-        Fh = ciq[:-1, :-1] - ciq[:-1, 1:]
-        Fv = ciq[:-1, :-1] - ciq[1:, :-1]
-        Fd = ciq[:-1, :-1] - ciq[1:, 1:]
-        Fm = ciq[:-1, 1:] - ciq[1:, :-1]
+        Fh = (ciq[:-1, :-1] - ciq[:-1, 1:]).clip(-T, T)
+        Fv = (ciq[:-1, :-1] - ciq[1:, :-1]).clip(-T, T)
+        Fd = (ciq[:-1, :-1] - ciq[1:, 1:]).clip(-T, T)
+        Fm = (ciq[:-1, 1:] - ciq[1:, :-1]).clip(-T, T)
         Fh1 = Fh[:-1, :-1]
         Fh2 = Fh[:-1, 1:]
@@ -101,14 +103,21 @@ class MPB(StegBase):
         # timer = Timer()
-        ciq = np.absolute(ciq).clip(0, T)
+        # ciq = np.absolute(ciq).clip(0, T) # Fool !!!
+        ciq = np.absolute(ciq)
         TPM = np.zeros((2 * T + 1, 2 * T + 1, 4), np.float64)
         # Fh = np.diff(ciq, axis=-1)
         # Fv = np.diff(ciq, axis=0)
-        Fh = ciq[:-1, :-1] - ciq[:-1, 1:]
-        Fv = ciq[:-1, :-1] - ciq[1:, :-1]
-        Fd = ciq[:-1, :-1] - ciq[1:, 1:]
-        Fm = ciq[:-1, 1:] - ciq[1:, :-1]
+
+        # Fh = ciq[:-1, :-1] - ciq[:-1, 1:]
+        # Fv = ciq[:-1, :-1] - ciq[1:, :-1]
+        # Fd = ciq[:-1, :-1] - ciq[1:, 1:]
+        # Fm = ciq[:-1, 1:] - ciq[1:, :-1]
+
+        Fh = (ciq[:-1, :-1] - ciq[:-1, 1:]).clip(-T, T)
+        Fv = (ciq[:-1, :-1] - ciq[1:, :-1]).clip(-T, T)
+        Fd = (ciq[:-1, :-1] - ciq[1:, 1:]).clip(-T, T)
+        Fm = (ciq[:-1, 1:] - ciq[1:, :-1]).clip(-T, T)
         Fh1 = Fh[:-1, :-1].ravel()
         Fh2 = Fh[:-1, 1:].ravel()
@@ -135,7 +144,7 @@ class MPB(StegBase):
         # 1.459668s
         # timer.mark()
         # for i in range(len(Fh1)):
-        #     TPM[Fh1[i], Fh2[i], 0] += 1
+        # TPM[Fh1[i], Fh2[i], 0] += 1
         # for i in range(len(Fv1)):
         #     TPM[Fv1[i], Fv2[i], 1] += 1
         # for i in range(len(Fd1)):