Python data.checkerboard函数代码示例

def test_swirl():
    image = img_as_float(data.checkerboard())

    swirl_params = {'radius': 80, 'rotation': 0, 'order': 2, 'mode': 'reflect'}
    swirled = tf.swirl(image, strength=10, **swirl_params)
    unswirled = tf.swirl(swirled, strength=-10, **swirl_params)

    assert np.mean(np.abs(image - unswirled)) < 0.01

def test_probabilistic_hough_seed():
    # Load image that is likely to give a randomly varying number of lines
    image = data.checkerboard()

    # Use constant seed to ensure a deterministic output
    lines = transform.probabilistic_hough_line(image, threshold=50,
                                               line_length=50, line_gap=1,
                                               seed=1234)
    assert len(lines) == 65

def test_swirl():
    image = img_as_float(data.checkerboard())

    swirl_params = {'radius': 80, 'rotation': 0, 'order': 2, 'mode': 'reflect'}

    with expected_warnings(['Bi-quadratic.*bug']):
        swirled = tf.swirl(image, strength=10, **swirl_params)
        unswirled = tf.swirl(swirled, strength=-10, **swirl_params)

    assert np.mean(np.abs(image - unswirled)) < 0.01

def main():
    """Load image, calculate harris scores (window functions: matrix of ones, gauss)
    and plot the results."""
    img = data.checkerboard()
    score_window = harris_ones(img, 7)
    score_gauss = harris_gauss(img)
    util.plot_images_grayscale(
        [img, score_window, score_gauss, feature.corner_harris(img)],
        ["Image", "Harris-Score (ones)", "Harris-Score (gauss)", "Harris-Score (ground truth)"]
    )

def main():
    """Apply several gaussian filters one by one and plot the results each time."""
    img = data.checkerboard()
    shapes = [(5, 5), (7, 7), (11, 11), (17, 17), (31, 31)]
    sigmas = [0.5, 1.0, 2.0, 4.0, 8.0]
    smoothed = []
    for shape, sigma in zip(shapes, sigmas):
        smoothed = apply_gauss(img, gaussian_kernel(shape, sigma=sigma))
        ground_truth = filters.gaussian_filter(img, sigma)
        util.plot_images_grayscale(
            [img, smoothed, ground_truth],
            ["Image", "After gauss (sigma=%.1f)" % (sigma), "Ground Truth (scipy)"]
        )

def profile():
    import time
    from iib.simulation import CLContext
    from skimage import io, data, transform
    gs, wgs = 256, 16

    # Load some test data
    r = transform.resize
    sigs = np.empty((gs, gs, 4), np.float32)
    sigs[:, :, 0] = r(data.coins().astype(np.float32) / 255.0, (gs, gs))
    sigs[:, :, 1] = r(data.camera().astype(np.float32) / 255.0, (gs, gs))
    sigs[:, :, 2] = r(data.text().astype(np.float32) / 255.0, (gs, gs))
    sigs[:, :, 3] = r(data.checkerboard().astype(np.float32) / 255.0, (gs, gs))
    sigs[:, :, 2] = r(io.imread("../scoring/corpus/rds/turing_001.png",
                                as_grey=True), (gs, gs))
    sigs[:, :, 3] = io.imread("../scoring/corpus/synthetic/blobs.png",
                              as_grey=True)
    sigs = sigs.reshape(gs*gs*4)

    # Set up OpenCL
    ctx = cl.create_some_context(interactive=False)
    queue = cl.CommandQueue(ctx)
    mf = cl.mem_flags
    ifmt_f = cl.ImageFormat(cl.channel_order.RGBA, cl.channel_type.FLOAT)
    bufi = cl.Image(ctx, mf.READ_ONLY, ifmt_f, (gs, gs))
    cl.enqueue_copy(queue, bufi, sigs, origin=(0, 0), region=(gs, gs))
    clctx = CLContext(ctx, queue, ifmt_f, gs, wgs)

    # Compile the kernels
    feats = cl.Program(ctx, features_cl()).build()
    rdctn = cl.Program(ctx, reduction.reduction_sum_cl()).build()
    blur2 = cl.Program(ctx, convolution.gaussian_cl([np.sqrt(2.0)]*4)).build()
    blur4 = cl.Program(ctx, convolution.gaussian_cl([np.sqrt(4.0)]*4)).build()

    iters = 500
    t0 = time.time()
    for i in range(iters):
        get_features(clctx, feats, rdctn, blur2, blur4, bufi)
    print((time.time() - t0)/iters)

    \phi = \mathtt{rotation}

    s = \mathtt{strength}

    \\theta' = \phi + s \, e^{-\\rho / r + \\theta}

where ``strength`` is a parameter for the amount of swirl, ``radius`` indicates
the swirl extent in pixels, and ``rotation`` adds a rotation angle.  The
transformation of ``radius`` into :math:`r` is to ensure that the
transformation decays to :math:`\\approx 1/1000^{\mathsf{th}}` within the
specified radius.

"""
import matplotlib.pyplot as plt

from skimage import data
from skimage.transform import swirl


image = data.checkerboard()
swirled = swirl(image, rotation=0, strength=10, radius=120, order=2)

fig, (ax0, ax1) = plt.subplots(1, 2, figsize=(8, 3), sharex=True, sharey=True, subplot_kw={'adjustable':'box-forced'})

ax0.imshow(image, cmap=plt.cm.gray, interpolation='none')
ax0.axis('off')
ax1.imshow(swirled, cmap=plt.cm.gray, interpolation='none')
ax1.axis('off')

plt.show()

def test_checkerboard():
    """ Test that "checkerboard" image can be loaded. """
    data.checkerboard()

to robustly estimate the parameter set by detecting outliers.

"""
import numpy as np
from matplotlib import pyplot as plt

from skimage import data
from skimage.feature import corner_harris, corner_subpix, corner_peaks
from skimage.transform import warp, AffineTransform
from skimage.exposure import rescale_intensity
from skimage.color import rgb2gray
from skimage.measure import ransac


# generate synthetic checkerboard image and add gradient for the later matching
checkerboard = data.checkerboard()
img_orig = np.zeros(list(checkerboard.shape) + [3])
img_orig[..., 0] = checkerboard
gradient_r, gradient_c = np.mgrid[0:img_orig.shape[0], 0:img_orig.shape[1]]
img_orig[..., 1] = gradient_r
img_orig[..., 2] = gradient_c
img_orig = rescale_intensity(img_orig)
img_orig_gray = rgb2gray(img_orig)

# warp synthetic image
tform = AffineTransform(scale=(0.9, 0.9), rotation=0.2, translation=(20, -10))
img_warped = warp(img_orig, tform.inverse, output_shape=(200, 200))
img_warped_gray = rgb2gray(img_warped)

# extract corners using Harris' corner measure
coords_orig = corner_peaks(corner_harris(img_orig_gray), threshold_rel=0.001,

def test_checkerboard():
    """ Test that checkerboard image can be loaded. """
    checkerboard = data.checkerboard()

    PYWAVELET_ND_INDEXING_WARNING = None

try:
    import dask
except ImportError:
    DASK_NOT_INSTALLED_WARNING = 'The optional dask dependency is not installed'
else:
    DASK_NOT_INSTALLED_WARNING = None


np.random.seed(1234)


astro = img_as_float(data.astronaut()[:128, :128])
astro_gray = color.rgb2gray(astro)
checkerboard_gray = img_as_float(data.checkerboard())
checkerboard = color.gray2rgb(checkerboard_gray)


def test_denoise_tv_chambolle_2d():
    # astronaut image
    img = astro_gray.copy()
    # add noise to astronaut
    img += 0.5 * img.std() * np.random.rand(*img.shape)
    # clip noise so that it does not exceed allowed range for float images.
    img = np.clip(img, 0, 1)
    # denoise
    denoised_astro = restoration.denoise_tv_chambolle(img, weight=0.1)
    # which dtype?
    assert_(denoised_astro.dtype in [np.float, np.float32, np.float64])
    from scipy import ndimage as ndi

"""
Affine transform
=================

Warping and affine transforms of images.
"""

from matplotlib import pyplot as plt

from skimage import data
from skimage.feature import corner_harris, corner_subpix, corner_peaks
from skimage.transform import warp, AffineTransform


tform = AffineTransform(scale=(1.3, 1.1), rotation=1, shear=0.7,
                        translation=(210, 50))
image = warp(data.checkerboard(), tform.inverse, output_shape=(350, 350))

coords = corner_peaks(corner_harris(image), min_distance=5)
coords_subpix = corner_subpix(image, coords, window_size=13)

plt.gray()
plt.imshow(image, interpolation='nearest')
plt.plot(coords_subpix[:, 1], coords_subpix[:, 0], '+r', markersize=15, mew=5)
plt.plot(coords[:, 1], coords[:, 0], '.b', markersize=7)
plt.axis('off')
plt.show()

# -*- coding: utf-8 -*-
"""
Created on Mon Sep 21 13:10:04 2015

@author: prassanna
"""

###FILTERS AND BLURRING############

from skimage import filter,io,data,color,feature,img_as_float
from matplotlib import pyplot as plt
import numpy as np

img = img_as_float(data.checkerboard());
print img.shape
io.imshow(img)

##Gaussian
noisy = img + 0.6 * img.std() * np.random.random(img.shape)
noisy = np.clip(noisy, 0, 1)
blurred = filter.gaussian_filter(noisy, 2);
#blurred_int = np.uint8(blurred*255)
#print np.amax(blurred_int)
bla = np.vstack((img,noisy,blurred))
io.imshow(bla)


#2nd Gaussian
from math import sqrt
img_2  = data.hubble_deep_field()
img_2  = img_2 [0:500,0:500]

def test():
    import matplotlib.pyplot as plt
    from skimage import io, data, transform
    from iib.simulation import CLContext

    gs, wgs = 256, 16

    # Load some test data
    r = transform.resize
    sigs = np.empty((gs, gs, 4), np.float32)
    sigs[:, :, 0] = r(data.coins().astype(np.float32) / 255.0, (gs, gs))
    sigs[:, :, 1] = r(data.camera().astype(np.float32) / 255.0, (gs, gs))
    sigs[:, :, 2] = r(data.text().astype(np.float32) / 255.0, (gs, gs))
    sigs[:, :, 3] = r(data.checkerboard().astype(np.float32) / 255.0, (gs, gs))
    sigs[:, :, 2] = r(io.imread("../scoring/corpus/rds/turing_001.png",
                                as_grey=True), (gs, gs))
    sigs[:, :, 3] = io.imread("../scoring/corpus/synthetic/blobs.png",
                              as_grey=True)
    #sq = np.arange(256).astype(np.float32).reshape((16, 16)) / 255.0
    #sigs[:, :, 0] = np.tile(sq, (16, 16))
    sigs = sigs.reshape(gs*gs*4)

    # Set up OpenCL
    ctx = cl.create_some_context(interactive=False)
    queue = cl.CommandQueue(ctx)
    mf = cl.mem_flags
    ifmt_f = cl.ImageFormat(cl.channel_order.RGBA, cl.channel_type.FLOAT)
    bufi = cl.Image(ctx, mf.READ_ONLY, ifmt_f, (gs, gs))
    cl.enqueue_copy(queue, bufi, sigs, origin=(0, 0), region=(gs, gs))
    clctx = CLContext(ctx, queue, ifmt_f, gs, wgs)

    # Compile the kernels
    feats = cl.Program(ctx, features_cl()).build()
    rdctn = cl.Program(ctx, reduction.reduction_sum_cl()).build()
    blur2 = cl.Program(ctx, convolution.gaussian_cl([np.sqrt(2.0)]*4)).build()
    blur4 = cl.Program(ctx, convolution.gaussian_cl([np.sqrt(4.0)]*4)).build()

    entropy = get_entropy(clctx, feats, rdctn, bufi)
    print("Average entropy:", entropy)

    variance = get_variance(clctx, feats, rdctn, bufi)
    print("Variance:", variance)

    edges = get_edges(clctx, feats, rdctn, blur4, bufi, summarise=False)
    edge_counts = get_edges(clctx, feats, rdctn, blur4, bufi)
    print("Edge pixel counts:", edge_counts)

    blobs = get_blobs(clctx, feats, rdctn, blur2, bufi, summarise=False)

    features = get_features(clctx, feats, rdctn, blur2, blur4, bufi)
    print("Feature vector:")
    print(features)

    # Plot the edges and blobs
    for i in range(4):
        plt.subplot(4, 3, i*3+1)
        img = sigs.reshape((gs, gs, 4))[:, :, i]
        plt.imshow(img, cmap="gray")
        plt.xticks([])
        plt.yticks([])

        plt.subplot(4, 3, i*3+2)
        img = edges.reshape((gs, gs, 4))[:, :, i]
        plt.imshow(img, cmap="gray")
        plt.xticks([])
        plt.yticks([])

        ax = plt.subplot(4, 3, i*3+3)
        img = sigs.reshape((gs, gs, 4))[:, :, i]
        plt.imshow(img, cmap="gray")
        plt.xticks([])
        plt.yticks([])
        for j in range(len(blobs)):
            sblobs = blobs[j]
            s = 2**(j+1)
            r = np.sqrt(2.0) * s
            im = sblobs[:, :, i]
            posns = np.transpose(im.nonzero()) * 2**(j+1)
            for xy in posns:
                circ = plt.Circle((xy[1], xy[0]), r, color="green", fill=False)
                ax.add_patch(circ)
    plt.show()

arg1 = sys.argv[1]

if int(arg1):
    print "using autojit"

autojit = autojit if int(arg1) else lambda: (lambda x: x)
jit = jit if int(arg1) else lambda x: (lambda x: x)

print autojit

print "generating checkerboard"
t = time.time()
tform = AffineTransform(scale=(1.3, 1.1), rotation=1, shear=0.7,
                            translation=(210, 50))
image = warp(data.checkerboard(), tform.inverse, output_shape=(5000, 5000))
# rr, cc = ellipse(310, 175, 100, 100)
#
# image[rr, cc] = 1
print "took", time.time() - t

print "generating squares"

@jit('void()')
def generate_squares_niave():
    for i in range(0, 5*50, 50):
        for j in range(180 + i, 230 + i):
            for k in range(10 + i, 60 + i):
                image[j, k] = 1
        for j in range(230 + i, 280 + i):
            for k in range(60 + i, 110 + i):