mirror of https://github.com/opencv/opencv.git
Open Source Computer Vision Library
https://opencv.org/
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
46 lines
1.4 KiB
46 lines
1.4 KiB
#!/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/gpu/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) |