Python filter.sobel函数代码示例

def get_edges(img):
    edge = np.empty(img.shape)
    if len(img.shape) == 3:
        for i in range(3):
            edge[:, :, i] = imfilt.sobel(img[:, :, i])
    else:
        edge = imfilt.sobel(img)
    edge = rescale_intensity(edge)
    return edge

    def test_convolution_upcast(self):
        i, j = np.mgrid[-5:6, -5:6]
        image = np.load(os.path.join(data_dir, 'lena_GRAY_U8.npy'))

        result1 = F.sobel(image)
        image = image.astype(float)
        result2 = F.sobel(image)

        assert_array_equal(result1, result2)

def sobel(data, sliceId=2):
    edges = np.zeros(data.shape)
    if sliceId == 2:
        for idx in range(data.shape[2]):
            edges[:, :, idx] = skifil.sobel(data[:, :, idx])
    elif sliceId == 0:
        for idx in range(data.shape[0]):
            edges[idx, :, :] = skifil.sobel(data[idx, :, :])
    return edges

    def segment(self, src):
        image = src.ndarray[:]
        if self.use_adaptive_threshold:
            block_size = 25
            markers = threshold_adaptive(image, block_size) * 255
            markers = invert(markers)

        else:
            markers = zeros_like(image)
            markers[image < self.threshold_low] = 1
            markers[image > self.threshold_high] = 255

        elmap = sobel(image, mask=image)
        wsrc = watershed(elmap, markers, mask=image)

#        elmap = ndimage.distance_transform_edt(image)
#        local_maxi = is_local_maximum(elmap, image,
#                                      ones((3, 3))
#                                      )
#        markers = ndimage.label(local_maxi)[0]
#        wsrc = watershed(-elmap, markers, mask=image)
#        fwsrc = ndimage.binary_fill_holes(out)
#        return wsrc
        if self.use_inverted_image:
            out = invert(wsrc)
        else:
            out = wsrc

#        time.sleep(1)
#        do_later(lambda:self.show_image(image, -elmap, out))
        return out

    def segment(self, src):
        '''
            pychron: preprocessing cv.Mat
        '''
#        image = pychron.ndarray[:]
#         image = asarray(pychron)
        image = src[:]
        if self.use_adaptive_threshold:
#            block_size = 25
            markers = threshold_adaptive(image, self.block_size)

            n = markers[:].astype('uint8')
            n[markers == True] = 255
            n[markers == False] = 1
            markers = n

        else:
            markers = zeros_like(image)
            markers[image < self.threshold_low] = 1
            markers[image > self.threshold_high] = 255

        elmap = sobel(image, mask=image)
        wsrc = watershed(elmap, markers, mask=image)

#         wsrc = wsrc.astype('uint8')
        return invert(wsrc)

def watershed_3d(sphere):
    """
    Markers should be int8
    Image should be uint8
    """
   
    sphere = median_filter(sphere, 3)
    thresh = threshold_otsu(sphere)
    sphere = (sphere >= thresh) * 1
    sphere = sobel(sphere)
    
    size = (sphere.shape[0], sphere.shape[1], sphere.shape[2])
    
    marker = np.zeros(size, dtype=np.int16)
    pl.imshow(sphere[:,:,50])
    pl.show()
    # mark everything outside as background
    marker[5, :, :] = -1
    marker[size[0] - 5, :, :] = -1
    marker[:, :, 5] = -1
    marker[:, :, size[2] - 5] = -1
    marker[:, 5, :] = -1
    marker[:, size[1] - 5, :] = -1
    marker[:,0,0] = -1
    # mark everything inside as a sphere
    marker[size[0] / 2., size[1] / 2., size[2] / 2.] = 5

    result = measurements.watershed_ift(sphere.astype(dtype=np.uint16), marker)
    pl.imshow(result[:,:,50])
    pl.show()
    
    return result

 def houghLine(img2d):
     "gray input"
     med_filter = ndimg.median_filter(img2d, size = (5,5))
     edges = filter.sobel(med_filter/255.)
     [H,theta,distances] = transform.hough_line(edges);
     imgsize = float(len(theta)*len(distances))
     return H.sum()/imgsize

    def __init__(self):
        self.logo = scipy_logo.ScipyLogo(radius=self.radius)
        self.mask_1 = self.logo.get_mask(self.image.shape, 'upper left')
        self.mask_2 = self.logo.get_mask(self.image.shape, 'lower right')

        edges = np.array([sobel(img) for img in self.image.T]).T
        # truncate and stretch intensity range to enhance contrast
        self.edges = rescale_intensity(edges, in_range=(0, 0.4))

def detect_edges(image):
    # 1. convert to grayscale image
    image_gray = rgb2gray(image)
    # 2. convolve with Sobel filter
    image_sobel = sobel(image_gray)
    # 3. compute binary edge image with threshold from Otsu's method
    image_edges = image_sobel > threshold_otsu(image_sobel)
    return image_sobel, image_edges

def test_sobel_vertical():
    """Sobel on a vertical edge should be a vertical line."""
    i, j = np.mgrid[-5:6, -5:6]
    image = (j >= 0).astype(float)
    result = F.sobel(image) * np.sqrt(2)
    j[np.abs(i) == 5] = 10000
    assert (np.all(result[j == 0] == 1))
    assert (np.all(result[np.abs(j) > 1] == 0))

 def test_01_01_horizontal(self):
     """Sobel on an edge should be a horizontal line"""
     i, j = np.mgrid[-5:6, -5:6]
     image = (i >= 0).astype(float)
     result = F.sobel(image)
     # Fudge the eroded points
     i[np.abs(j) == 5] = 10000
     assert (np.all(result[i == 0] == 1))
     assert (np.all(result[np.abs(i) > 1] == 0))

def dynamic_masking(image,method='edges',filter_size=7,threshold=0.005):
    """ Dynamically masks out the objects in the PIV images
    
    Parameters
    ----------
    image: image
        a two dimensional array of uint16, uint8 or similar type
        
    method: string
        'edges' or 'intensity':
        'edges' method is used for relatively dark and sharp objects, with visible edges, on 
        dark backgrounds, i.e. low contrast
        'intensity' method is useful for smooth bright objects or dark objects or vice versa, 
        i.e. images with high contrast between the object and the background
    
    filter_size: integer
        a scalar that defines the size of the Gaussian filter
    
    threshold: float
        a value of the threshold to segment the background from the object
        default value: None, replaced by sckimage.filter.threshold_otsu value
            
    Returns
    -------
    image : array of the same datatype as the incoming image with the object masked out
        as a completely black region(s) of zeros (integers or floats).
    
    
    Example
    --------
    frame_a  = openpiv.tools.imread( 'Camera1-001.tif' )
    imshow(frame_a) # original
    
    frame_a = dynamic_masking(frame_a,method='edges',filter_size=7,threshold=0.005)
    imshow(frame_a) # masked 
        
    """
    imcopy = np.copy(image)
    # stretch the histogram
    image = exposure.rescale_intensity(img_as_float(image), in_range=(0, 1))
    # blur the image, low-pass
    blurback = gaussian_filter(image,filter_size)
    if method is 'edges':
        # identify edges
        edges = sobel(blurback)
        blur_edges = gaussian_filter(edges,21)
        # create the boolean mask 
        bw = (blur_edges > threshold)
        bw = binary_fill_holes(bw)
        imcopy -= blurback
        imcopy[bw] = 0.0
    elif method is 'intensity':
        background = gaussian_filter(median_filter(image,filter_size),filter_size)
        imcopy[background > threshold_otsu(background)] = 0

        
    return imcopy #image

def sobelgm(provider):
    """
    mean sobel gradient magnitude
    """
    gray = provider.as_gray()
    mag = sobel(gray)
    mag *= 100.0 / np.max(mag)

    return np.mean(mag)

def test_sobel_horizontal():
    """Sobel on a horizontal edge should be a horizontal line."""
    i, j = np.mgrid[-5:6, -5:6]
    image = (i >= 0).astype(float)
    result = F.sobel(image) * np.sqrt(2)
    # Fudge the eroded points
    i[np.abs(j) == 5] = 10000
    assert_allclose(result[i == 0], 1)
    assert (np.all(result[np.abs(i) > 1] == 0))

	def edge(self):
		'''
		implements a edge detection
		'''

		self.img = self.img.mean(2)
		self.img = filter.sobel(self.img)

		self.refreshimg()