def test_rotated_lena():
"""
The harris filter should yield the same results with an image and it's
rotation.
"""
im = img_as_float(data.lena().mean(axis=2))
results = harris(im)
im_rotated = im.T
results_rotated = harris(im_rotated)
assert (np.sort(results[:, 0]) == np.sort(results_rotated[:, 1])).all()
assert (np.sort(results[:, 1]) == np.sort(results_rotated[:, 0])).all()
def test_rotated_lena():
"""
The harris filter should yield the same results with an image and it's
rotation.
"""
im = img_as_float(data.lena().mean(axis=2))
results = harris(im)
im_rotated = im.T
results_rotated = harris(im_rotated)
assert (np.sort(results[:, 0]) == np.sort(results_rotated[:, 1])).all()
assert (np.sort(results[:, 1]) == np.sort(results_rotated[:, 0])).all()
def test_noisy_square_image():
im = np.zeros((50, 50)).astype(float)
im[:25, :25] = 1.
im = im + np.random.uniform(size=im.shape) * .5
results = harris(im)
assert results.any()
assert len(results) == 1
def test_squared_dot():
im = np.zeros((50, 50))
im[4:8, 4:8] = 1
im = img_as_float(im)
results = harris(im, min_distance=3)
print results
assert (results == np.array([[6, 6]])).all()
def guess_corners(bw):
"""
Infer the corners of an image using a Sobel filter to find the edges and a
Harris filter to find the corners. Takes only as single color chanel.
Parameters
----------
bw : (m x n) ndarray of ints
Returns
-------
corners : pixel coordinates of plot corners, unsorted
outline : (m x n) ndarray of bools True -> plot area
"""
assert len(bw.shape) == 2
bw = img_as_uint(bw)
e_map = ndimage.sobel(bw)
markers = np.zeros(bw.shape, dtype=int)
markers[bw < 30] = 1
markers[bw > 150] = 2
seg = ndimage.watershed_ift(e_map, np.asarray(markers, dtype=int))
outline = ndimage.binary_fill_holes(1 - seg)
corners = harris(np.asarray(outline, dtype=int))
corners = approximate_polygon(corners, 1)
return corners, outline
def test_noisy_square_image():
im = np.zeros((50, 50)).astype(float)
im[:25, :25] = 1.
im = im + np.random.uniform(size=im.shape) * .5
results = harris(im)
assert results.any()
assert len(results) == 1
def get_wire_tip_coordinates(self):
"this should actually find the tip with the harris algorithm"
y, x = numpy.transpose(
feature.harris(self.image,
min_distance=100,
threshold=0.3,
gaussian_deviation=5))
n = x.size
x, y = x[0], y[0]
return x, y, n
def harris(parameters):
"""Harris interest point operator.
It wraps `skimage.feature.harris`. The `threshold`, `eps` and
`gaussian_deviation` options are not supported.
This function returns an array of 0s and 1s. Harris points are marked
with 1s. This way the result can be easily transformed to an image. It
works on RGB and greyscale images.
The wrapped function returns a set of point coordinates in a list. For
some reason it is not possible to do something like:
>>> points = feature.harris(data, min_distance=5)
>>> data[points] = 1
so a for loop is used.
.. note::
The coordinates returned are not directly on the corner, but a pixel
inside the object (TODO: is this expected?).
:param parameters['data'][0]: input array
:type parameters['data'][0]: numpy.array
:param parameters['min_distance']: minimum number of pixels separating
interest points and image boundary,
defaults to 10
:type parameters['min_distance']: float
:return: numpy.array, it contains 1s where points were found, otherwise 0
"""
data = parameters['data'][0]
min_distance = parameters.get('min_distance', 10)
points = feature.harris(data, min_distance=min_distance)
result = numpy.zeros((data.shape[0], data.shape[1]), dtype='uint8')
for point in points:
result[point[0], point[1]] = 1
return result
def harris(parameters):
"""Harris interest point operator.
It wraps `skimage.feature.harris`. The `threshold`, `eps` and
`gaussian_deviation` options are not supported.
This function returns an array of 0s and 1s. Harris points are marked
with 1s. This way the result can be easily transformed to an image. It
works on RGB and greyscale images.
The wrapped function returns a set of point coordinates in a list. For
some reason it is not possible to do something like:
>>> points = feature.harris(data, min_distance=5)
>>> data[points] = 1
so a for loop is used.
.. note::
The coordinates returned are not directly on the corner, but a pixel
inside the object (TODO: is this expected?).
:param parameters['data'][0]: input array
:type parameters['data'][0]: numpy.array
:param parameters['min_distance']: minimum number of pixels separating
interest points and image boundary,
defaults to 10
:type parameters['min_distance']: float
:return: numpy.array, it contains 1s where points were found, otherwise 0
"""
data = parameters['data'][0]
min_distance = parameters.get('min_distance', 10)
points = feature.harris(data, min_distance=min_distance)
result = numpy.zeros((data.shape[0], data.shape[1]), dtype='uint8')
for point in points:
result[point[0], point[1]] = 1
return result
from matplotlib import pyplot as plt
from skimage import data, img_as_float
from skimage.feature import harris
def plot_harris_points(image, filtered_coords):
""" plots corners found in image"""
plt.imshow(image)
y, x = np.transpose(filtered_coords)
plt.plot(x, y, 'b.')
plt.axis('off')
# display results
plt.figure(figsize=(8, 3))
im_lena = img_as_float(data.lena())
im_text = img_as_float(data.text())
filtered_coords = harris(im_lena, min_distance=4)
plt.axes([0, 0, 0.3, 0.95])
plot_harris_points(im_lena, filtered_coords)
filtered_coords = harris(im_text, min_distance=4)
plt.axes([0.2, 0, 0.77, 1])
plot_harris_points(im_text, filtered_coords)
plt.show()
def extract_features(image_path_list):
'''
Our feature extraction function. It takes in a list of image paths,
does some measurement on each image, then returns a list of the image paths
paired with the results of the feature measurement.
'''
feature_list = []
for image_path in image_path_list:
image_array = imread(image_path)
if len(image_array.shape) != 3:
image_array = color.gray2rgb(image_array)
# Create a sub-image of the center. Useful for color of subject.
height, width = image_array.shape[0], image_array.shape[1]
central_y, central_x = int(round(height/2.0)), int(round(width/2.0))
central_image_array = image_array[central_y-height/10 : central_y+height/10, central_x-width/10 : central_x+width/10, :]
# crop to square integer 16x16 size
new_height, new_width = 16*(height/16), 16*(width/16)
if new_height < new_width: new_width = new_height
elif new_height > new_width: new_height = new_width
cropped_image_array = image_array[central_y-new_height/2 : central_y+new_height/2, central_x-new_width/2 : central_x+new_width/2, :]
#Equalize the image
image_array_gray_equalized = exposure.equalize(color.rgb2gray(cropped_image_array))
# Now zoom it to 128x128 for easier shape processing
small_square_gray_image = ndimage.interpolation.zoom(image_array_gray_equalized, 128.0/new_height)
# Create sobel filtered image
sobel_image = ndimage.filters.sobel(image_array)
# (1) Number of pixels in the image (super simple)
n_pixels = image_array.size
# (2) Median red value
med_red_val = median(central_image_array[:,:,0])
# (3) Median green value
med_green_val = median(central_image_array[:,:,1])
# (4) Median blue value
med_blue_val = median(central_image_array[:,:,2])
# (5) Standard Deviation of red value
std_red_val = central_image_array[:,:,0].std()
# (6) Standard Deviation of green value
std_green_val = central_image_array[:,:,1].std()
# (7) Standard Deviation of blue value
std_blue_val = central_image_array[:,:,2].std()
# (8) Image aspect ratio (width/height)
aspect_ratio = float(width)/height
# (9) Histogram Otsu thershold
otsu_thresh = filter.threshold_otsu(image_array)
# (10, 11, 12) Center of Mass
center_of_mass_x, center_of_mass_y, center_of_mass_value = ndimage.measurements.center_of_mass(image_array)
# (13) Ratio of sum of bottom half vs top half of pixels
vertical_ratio = small_square_gray_image[:64,:].sum()/small_square_gray_image[64:,:].sum()
# (14) Ratio of sum of left half vs right half of pixels
horizontal_ratio = small_square_gray_image[:,:64].sum()/small_square_gray_image[:,64:].sum()
# (15, 16, 17) Location of maximum
max_x, max_y, max_band = ndimage.measurements.maximum_position(image_array)
# (18, 19, 20) Location of minimum
min_x, min_y, min_band = ndimage.measurements.minimum_position(image_array)
# (21) Median sobel red value
med_sobel_red_val = median(sobel_image[:,:,0])
# (22) Median sobel green value
med_sobel_green_val = median(sobel_image[:,:,1])
# (23) Median sobel blue value
med_sobel_blue_val = median(sobel_image[:,:,2])
# (24) Standard Deviation of sobel red value
std_sobel_red_val = sobel_image[:,:,0].std()
# (25) Standard Deviation of sobel green value
std_sobel_green_val = sobel_image[:,:,1].std()
# (26) Standard Deviation of sobel blue value
std_sobel_blue_val = sobel_image[:,:,2].std()
# (27) Number of Harris points
n_harris_points = feature.harris(small_square_gray_image, min_distance=6).size
# (28) Mean of Histogram of Gradients (HOG)
fd = feature.hog(image_array_gray_equalized, orientations=8, pixels_per_cell=(16, 16), cells_per_block=(1, 1), visualise=False)
mean_hog = fd.mean()
# (29) Standard Deviation of Histogram of Gradients (HOG)
std_hog = fd.std()
# (30) Ratio of white pixels in skeletonized image
edge_image = filter.canny(image_array_gray_equalized, sigma=1)
skeleton_image = morphology.skeletonize(edge_image)
skeleton_ratio = float(skeleton_image.sum())/skeleton_image.size
feature_list.append([image_path,
n_pixels,
med_red_val,
med_green_val,
med_blue_val,
std_red_val,
std_green_val,
std_blue_val,
aspect_ratio,
otsu_thresh,
center_of_mass_x,
center_of_mass_y,
center_of_mass_value,
vertical_ratio,
horizontal_ratio,
max_x,
max_y,
max_band,
min_x,
min_y,
min_band,
med_sobel_red_val,
med_sobel_green_val,
med_sobel_blue_val,
std_sobel_red_val,
std_sobel_green_val,
std_sobel_blue_val,
n_harris_points,
mean_hog,
std_hog,
skeleton_ratio])
return feature_list
from sklearn.datasets import load_sample_images
from matplotlib.pyplot import imshow, show, axis, plot
import numpy as np
from skimage.feature import harris
dataset = load_sample_images()
img = dataset.images[0]
harris_coords = harris(img)
print "Harris coords shape", harris_coords.shape
y, x = np.transpose(harris_coords)
axis('off')
imshow(img)
plot(x, y, 'ro')
show()
def test_squared_dot():
im = np.zeros((50, 50))
im[4:8, 4:8] = 1
im = img_as_float(im)
results = harris(im, min_distance=3)
assert (results == np.array([[6, 6]])).all()
def test_square_image():
im = np.zeros((50, 50)).astype(float)
im[:25, :25] = 1.
results = harris(im)
assert results.any()
assert len(results) == 1
def test_square_image():
im = np.zeros((50, 50)).astype(float)
im[:25, :25] = 1.
results = harris(im)
assert results.any()
assert len(results) == 1
from skimage import data, img_as_float
from skimage.feature import harris
def plot_harris_points(image, filtered_coords):
""" plots corners found in image"""
plt.imshow(image)
y, x = np.transpose(filtered_coords)
plt.plot(x, y, 'b.')
plt.axis('off')
# display results
plt.figure(figsize=(8, 3))
im_lena = img_as_float(data.lena())
im_text = img_as_float(data.text())
filtered_coords = harris(im_lena, min_distance=4)
plt.axes([0, 0, 0.3, 0.95])
plot_harris_points(im_lena, filtered_coords)
filtered_coords = harris(im_text, min_distance=4)
plt.axes([0.2, 0, 0.77, 1])
plot_harris_points(im_text, filtered_coords)
plt.show()
import numpy as np
from matplotlib import pyplot as plt
from skimage import data, img_as_float
from skimage.feature import harris
def plot_harris_points(image, filtered_coords):
plt.imshow(image)
y, x = np.transpose(filtered_coords)
plt.plot(x, y, 'b.')
plt.axis('off')
# resultados
plt.figure(figsize=(8, 3))
image = img_as_float(data.load("c.jpeg"))
filtered_coords = harris(image, min_distance=4)
plt.axes([0.2, 0, 0.77, 1])
plot_harris_points(image, filtered_coords)
plt.show()
from sklearn.datasets import load_sample_images
from matplotlib.pyplot import imshow, show, axis, plot
import numpy
from skimage.feature import harris
dataset = load_sample_images()
img = dataset.images[0]
harris_coords = harris(img)
print "Harris coords shape", harris_coords.shape
y, x = numpy.transpose(harris_coords)
axis('off')
imshow(img)
plot(x, y, 'ro')
show()
The Harris corner filter [1]_ detects "interest points" [2]_ using edge
detection in multiple directions.
.. [1] http://en.wikipedia.org/wiki/Corner_detection
.. [2] http://en.wikipedia.org/wiki/Interest_point_detection
"""
from matplotlib import pyplot as plt
from skimage import data, img_as_float
from skimage.feature import harris
def plot_harris_points(image, filtered_coords):
""" plots corners found in image"""
plt.plot()
plt.imshow(image)
plt.plot([p[1] for p in filtered_coords],
[p[0] for p in filtered_coords],
'b.')
plt.axis('off')
plt.show()
im = img_as_float(data.lena())
filtered_coords = harris(im, min_distance=6)
plot_harris_points(im, filtered_coords)