1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
|
#!/usr/bin/env python
'''
Test for disctrete fourier transform (dft)
'''
# Python 2/3 compatibility
from __future__ import print_function
import cv2
import numpy as np
import sys
from tests_common import NewOpenCVTests
class dft_test(NewOpenCVTests):
def test_dft(self):
img = self.get_sample('samples/data/rubberwhale1.png', 0)
eps = 0.001
#test direct transform
refDft = np.fft.fft2(img)
refDftShift = np.fft.fftshift(refDft)
refMagnitide = np.log(1.0 + np.abs(refDftShift))
testDft = cv2.dft(np.float32(img),flags = cv2.DFT_COMPLEX_OUTPUT)
testDftShift = np.fft.fftshift(testDft)
testMagnitude = np.log(1.0 + cv2.magnitude(testDftShift[:,:,0], testDftShift[:,:,1]))
refMagnitide = cv2.normalize(refMagnitide, 0.0, 1.0, cv2.NORM_MINMAX)
testMagnitude = cv2.normalize(testMagnitude, 0.0, 1.0, cv2.NORM_MINMAX)
self.assertLess(cv2.norm(refMagnitide - testMagnitude), eps)
#test inverse transform
img_back = np.fft.ifft2(refDft)
img_back = np.abs(img_back)
img_backTest = cv2.idft(testDft)
img_backTest = cv2.magnitude(img_backTest[:,:,0], img_backTest[:,:,1])
img_backTest = cv2.normalize(img_backTest, 0.0, 1.0, cv2.NORM_MINMAX)
img_back = cv2.normalize(img_back, 0.0, 1.0, cv2.NORM_MINMAX)
self.assertLess(cv2.norm(img_back - img_backTest), eps)
|
