PythonGray/j.py at master · dzienisz/PythonGray · GitHub

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import scipy.signal
import numpy as np
import matplotlib.pyplot as plt


def rgb2gray(rgb):
    '''

    convert rgb image to gray scale, it uses formula
    gray_img = 0.299 R + 0.587 G + 0.114 B

    '''

    return np.dot(rgb[..., :3], [0.299, 0.587, 0.114])


# read image
im = plt.imread("img/photo.png").astype(float)
gray = rgb2gray(im)
gray /= 255
plt.imshow(gray, interpolation='none', cmap=plt.cm.gray)

# emmboss filter
kernel = np.array([[-2, -1, 0], [-1, 1, 1], [0, 1, 2]])

em_img = scipy.signal.convolve2d(gray, kernel)
em_img *= 255

plt.subplot(1, 3, 1)
plt.imshow(im, interpolation='none', cmap=plt.cm.gray)
plt.subplot(1, 3, 2)
plt.imshow(gray, interpolation='none', cmap=plt.cm.gray)
plt.subplot(1, 3, 3)
plt.imshow(em_img, interpolation='none', cmap=plt.cm.gray)
plt.show()