I am trying to implement the Wiener Filter to perform deconvolution on blurred image. My implementation is like this
import numpy as np
from numpy.fft import fft2, ifft2
def wiener_filter(img, kernel, K = 10):
dummy = np.copy(img)
kernel = np.pad(kernel, [(0, dummy.shape[0] - kernel.shape[0]), (0, dummy.shape[1] - kernel.shape[1])], 'constant')
# Fourier Transform
dummy = fft2(dummy)
kernel = fft2(kernel)
kernel = np.conj(kernel) / (np.abs(kernel) ** 2 + K)
dummy = dummy * kernel
dummy = np.abs(ifft2(dummy))
return np.uint8(dummy)
This implementation is based on the Wiki Page.
The TIFF image used is from : http://www.ece.rice.edu/~wakin/images/lena512color.tiff
But here is a PNG version:
I have a input image motion blurred by a diagonal kernel and some gaussian additive noise is added to it. The lena picture is 512x512 and the blurring kernel is 11x11.
When I apply my wiener_filter to this image the result is like this. .
I think this deblurred image is not of good quality. So I would like to ask if my implementation is correct.
Update the way I add noise.
from scipy.signal import gaussian, convolve2d
def blur(img, mode = 'box', block_size = 3):
# mode = 'box' or 'gaussian' or 'motion'
dummy = np.copy(img)
if mode == 'box':
h = np.ones((block_size, block_size)) / block_size ** 2
elif mode == 'gaussian':
h = gaussian(block_size, block_size / 3).reshape(block_size, 1)
h = np.dot(h, h.transpose())
h /= np.sum(h)
elif mode == 'motion':
h = np.eye(block_size) / block_size
dummy = convolve2d(dummy, h, mode = 'valid')
return np.uint8(dummy), h
def gaussian_add(img, sigma = 5):
dummy = np.copy(img).astype(float)
gauss = np.random.normal(0, sigma, np.shape(img))
# Additive Noise
dummy = np.round(gauss + dummy)
# Saturate lower bound
dummy[np.where(dummy < 0)] = 0
# Saturate upper bound
dummy[np.where(dummy > 255)] = 255
return np.uint8(dummy)
For data comparison, you can find a sample implementation of Wiener filtering and unsupervisived Wiener filtering at
http://scikit-image.org/docs/dev/auto_examples/plot_restoration.html
If you give your original image data, we may be able to help further.
EDIT: Original link seems to be down, try this one: http://scikit-image.org/docs/dev/auto_examples/filters/plot_restoration.html