mirror of
https://github.com/opencv/opencv.git
synced 2024-12-02 16:00:17 +08:00
46 lines
1.4 KiB
Python
46 lines
1.4 KiB
Python
#!/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) |