Python exposure.adjust_gamma函数代码示例

 def compute_binary_diff_image(self, new_image):
     """
     Compute an Otsu-thresholded image corresponding to the
     absolute difference between the empty chessboard image and the
     current image.
     """
     adj_start_image = exposure.adjust_gamma(
                     color.rgb2gray(self.empty_chessboard_image), 0.1)
     # gamma values have a strong impact on classification
     adj_image = exposure.adjust_gamma(color.rgb2gray(new_image), 0.1)
     diff_image = exposure.adjust_gamma(np.abs(adj_image - adj_start_image),
                                        0.3)
     return diff_image > threshold_otsu(diff_image)

def image_prep(img):
	# apply filters for better contrast and noise removal
	img_gamma = adjust_gamma(img, 0.7)
	img_median = median(img_gamma, disk(1))

	# apply threshold
	val =  threshold_otsu(img_median)
	img_otsu = img_median > val

	# label image regions
	label_image = label(img_otsu)

	candidates = []
	for region in regionprops(label_image):
		minr, minc, maxr, maxc = region.bbox
		if (maxr - minr > maxc - minc):
			candidates.append(region)

	# find numbers
	areas = []
	for candidate in candidates:
		areas.append(candidate.area)
	areas.sort()
	areas.reverse()

	n = 1
	v = []
	for candidate in candidates:
		if (candidate.area == areas[0] or candidate.area == areas[1] or candidate.area == areas[2]):
			v.append(candidate.image)
			imsave('num%d.png' % n, candidate.image)
			n += 1
	return v

def gen_thumbs(dirname, key='/*/*decon.tif', where='host', level=2, figsize=6,
               redo=True, gamma=1.0, **kwargs):
    '''
    Main function to generate and save thumbnail pngs
    '''
    # load data
    data = load_data(dirname, key)
    if data:
        # can clean the dirnames here
        foldername = os.path.abspath(dirname).split(os.path.sep)[-level]
        if where == 'host':
            save_name = 'Thumbs ' + foldername + '.png'
        elif where == 'in folder':
            save_name = os.path.abspath(
                os.path.join(dirname, 'Thumbs ' + foldername + '.png'))
        else:
            save_name = os.path.abspath(
                os.path.join(where, 'Thumbs ' + foldername + '.png'))
        if not redo and os.path.exists(save_name):
            print(save_name, "already exists, skipping")
            return dirname + os.path.sep + key
        data = {clean_dirname(k, figsize): adjust_gamma(abs(v), gamma)
                for k, v in data.items()}
        fig, ax = display_grid(data, figsize=figsize, **kwargs)
        # make the layout 'tight'
        fig.tight_layout()
        # save the figure
        print('Saving', save_name, 'on', os.getpid(), '...')
        fig.savefig(save_name, bbox_inches='tight')
        print('finished saving', save_name)
    # mark data for gc
    del data
    return dirname + os.path.sep + key

def image_generate(img, ZCA_array) :
	timg = np.copy(img)
	timg = timg.transpose(1, 2, 0) # transpose to use skimage
	augnum = random.randrange(0, 5)
	
	if augnum==0 or augnum==1 : 
		# change nothing
		pass
	elif augnum==2 :
		# horizontal flip 
		for j in range(3) :
			timg[:,:,j] = np.fliplr(timg[:,:,j])
	elif augnum==3 :
		# random rotation of -15~15 degrees
		angle = random.random()*30-15
		timg = transform.rotate(timg/256.0, angle)
	elif augnum==4 :
		# gamma correction (luminance adjust) - random gamma 0.7~1.3
		gamma = random.random()*0.6+0.7
		timg = exposure.adjust_gamma(timg/256.0, gamma)

	timg = timg.transpose(2, 0, 1)
	# GCN, ZCA
	for i in range(3) :
		timg[i,:,:] -= np.mean(timg[i,:,:])
		timg[i,:,:] /= np.std(timg[i,:,:])
		timg[i,:,:] = np.dot(ZCA_array, timg[i,:,:].reshape(1024, 1)).reshape(32, 32)

	return timg

def gamma_correction(img=None, gamma=1., gain=1.):
    r'''
    Gamma correction or power law transform. It can be expressed as:

    .. math::
        I_{out} = gain \times {I_{in}} ^ {\gamma}

    Adjusts contrast without changing the shape of the histogram. For the values
    .. :math:`\gamma > 1` : Histogram shifts towards left (darker)
    .. :math:`\gamma < 1` : Histogram shifts towards right (lighter)

    Parameters
    ----------
    img : array_like
        Single image as numpy array or multiple images as array-like object
    gamma : float
        Non-negative real number
    gain : float
        Multiplying factor

    References
    ----------
    .. [1] http://scikit-image.org/docs/dev/auto_examples/color_exposure/plot_log_gamma.html # noqa
    .. [2] http://en.wikipedia.org/wiki/Gamma_correction

    '''
    img_out = exposure.adjust_gamma(img, gamma, gain)
    return img_out

    def save_segmented_image(self, filepath_image, modality='t1c', show=False):
        '''
        Creates an image of original brain with segmentation overlay and save it in ./predictions
        INPUT   (1) str 'filepath_image': filepath to test image for segmentation, including file extension
                (2) str 'modality': imaging modality to use as background. defaults to t1c. options: (flair, t1, t1c, t2)
                (3) bool 'show': If true, shows output image. defaults to False.
        OUTPUT  (1) if show is True, shows image of segmentation results
                (2) if show is false, returns segmented image.
        '''
        modes = {'flair': 0, 't1': 1, 't1c': 2, 't2': 3}

        segmentation = self.predict_image(filepath_image, show=False)
        print 'segmentation = ' + str(segmentation)
        img_mask = np.pad(segmentation, (16, 16), mode='edge')
        ones = np.argwhere(img_mask == 1)
        twos = np.argwhere(img_mask == 2)
        threes = np.argwhere(img_mask == 3)
        fours = np.argwhere(img_mask == 4)

        test_im = io.imread(filepath_image)
        test_back = test_im.reshape(5, 216, 160)[modes[modality]]
        # overlay = mark_boundaries(test_back, img_mask)
        gray_img = img_as_float(test_back)

        # adjust gamma of image
        image = adjust_gamma(color.gray2rgb(gray_img), 0.65)
        sliced_image = image.copy()
        red_multiplier = [1, 0.2, 0.2]
        yellow_multiplier = [1, 1, 0.25]
        green_multiplier = [0.35, 0.75, 0.25]
        blue_multiplier = [0, 0.25, 0.9]

        print str(len(ones))
        print str(len(twos))
        print str(len(threes))
        print str(len(fours))

        # change colors of segmented classes
        for i in xrange(len(ones)):
            sliced_image[ones[i][0]][ones[i][1]] = red_multiplier
        for i in xrange(len(twos)):
            sliced_image[twos[i][0]][twos[i][1]] = green_multiplier
        for i in xrange(len(threes)):
            sliced_image[threes[i][0]][threes[i][1]] = blue_multiplier
        for i in xrange(len(fours)):
            sliced_image[fours[i][0]][fours[i][1]] = yellow_multiplier
        #if show=True show the prediction
        if show:
            print 'Showing...'
            io.imshow(sliced_image)
            plt.show()
        #save the prediction
        print 'Saving...'
        try:
            mkdir_p('./predictions/')
            io.imsave('./predictions/' + os.path.basename(filepath_image) + '.png', sliced_image)
            print 'prediction saved.'
        except:
            io.imsave('./predictions/' + os.path.basename(filepath_image) + '.png', sliced_image)
            print 'prediction saved.'

 def __prepare_image(image):
     """Prepare image for comparison"""
     image = rgb2gray(image)
     image = adjust_gamma(image)
     image = pyramid_reduce(image, downscale=8)
     with warnings.catch_warnings():
         warnings.simplefilter("ignore")
         image = img_as_ubyte(image)
     return image

    def S2_image_to_rgb(self, rgb_bands=("B11", "B08", "B03"), rgb_gamma=(1.0, 1.0, 1.0),hist_chop_off_fraction=0.01,
                        output_size=None,max_hist_pixel=1000**2,resample_order=3):

        if output_size is None:
            if self.target_resolution is None:
                raise ValueError("output_size=None is only allowed for target_resolution != None")
            else:
                output_shape = list(self.final_shape)
        else:
            output_shape = [output_size,output_size]

        rgb_type = np.uint8
        S2_rgb = np.zeros(output_shape + [len(rgb_bands),],dtype=rgb_type)

        if self.unit == "reflectance":
            bins = np.linspace(0.0,1.0,100 / 2.0)
        elif self.unit == "dn":
            bins = np.linspace(0,10000,100 / 2.0)

        for i_rgb, (band, gamma) in enumerate(zip(rgb_bands, rgb_gamma)):
            if self.target_resolution is None:
                data = self.data[band]
            else:
                i_band = self.band_list.index(band)
                data = self.data[:,:,i_band]

            if self.bad_data_value is np.NAN:
                bf = data[:,:][np.isfinite(data[:,:])]
            else:
                bf = data[:,:][data[:,:] == self.bad_data_value]

            pixel_skip = np.int(np.floor(bf.shape[0] / max_hist_pixel) + 1)
            bf = bf[::pixel_skip]
            hh, xx = np.histogram(bf, bins=bins,normed=False)
            bb = 0.5 * (xx[1:] + xx[:-1])
            hist_chop_off = hist_chop_off_fraction * np.sum(hh) / len(bins)
            lim = (lambda x: (np.min(x), np.max(x)))(bb[hh > hist_chop_off])
            zoom_factor = np.array(output_shape) / np.array(data[:,:].shape)

            zm = np.nan_to_num(np.array(data[:, :],dtype=np.float32))
            if (zoom_factor != [1.0,1.0]).all():
                self.logger.info("Resample band for RGB image: %i,%s,zoom:%.2f" % (i_rgb, band,zoom_factor[0]))
                zm = zoom(input=zm,zoom=zoom_factor,order=resample_order)

            bf = rescale_intensity(image=zm,in_range=lim,out_range=(0.0, 255.0))
            S2_rgb[:, :, i_rgb] = np.array(bf,dtype=rgb_type)

            self.logger.info("Rescale band for RGB image: %i,%s,(%.2f,%.2f)->(0,256), zoom:%.2f" %
                             (i_rgb, band, lim[0], lim[1],zoom_factor[0]))

            if gamma != 0.0:
                S2_rgb[:, :, i_rgb] = np.array(
                        adjust_gamma(np.array(S2_rgb[:, :, i_rgb], dtype=np.float32),gamma),dtype=rgb_type)
        return S2_rgb

def make_square(img):
  height, width = img.shape
  max_side = max([height, width])

  copy = np.zeros(shape=(max_side, max_side), dtype=np.uint8)
  copy.fill(255)
  for i in range(height):
    for j in range(width):
      copy[i][j] = img[i][j]
  # increase contrast a bit with a gamma correction
  copy = exposure.adjust_gamma(copy, gamma=1.8)
  return copy

    def transform(self, Xb, yb):
        Xb, yb = super(AdjustGammaBatchIteratorMixin, self).transform(Xb, yb)
        Xb_transformed = Xb.copy()

        if self.adjust_gamma_p > 0:
            random_idx = get_random_idx(Xb, self.adjust_gamma_p)
            for i in random_idx:
                gamma = choice(self.adjust_gamma_chocies)
                Xb_transformed[i] = adjust_gamma(
                    Xb[i].transpose(1, 2, 0), gamma=gamma
                ).transpose(2, 0, 1)

        return Xb_transformed, yb

 def call(self, image, saliency_image):
     img_resize = resize(image, saliency_image.shape)
     saliency_range = max(0.15, saliency_image.max() - saliency_image.min())
     saliency_norm = (saliency_image - saliency_image.min()) / saliency_range
     saliency_gamma = adjust_gamma(saliency_norm, gamma=self.gamma)
     cmap = matplotlib.cm.get_cmap('viridis')
     cmap_hsv = rgb2hsv(cmap(saliency_gamma)[:, :, :3])
     hsv = np.stack([
         cmap_hsv[:, :, 0],
         saliency_gamma,
         img_resize
     ], axis=-1)
     return hsv2rgb(hsv)

    def save_segmented_image(self, index, test_img, save=False):
        """
        Creates an image of original brain with segmentation overlay
        :param index: index of image to save
        :param test_img: filepath to test image for segmentation, including file extension
        :param save: If true, shows output image. (defaults to False)
        :return: if show is True, shows image of segmentation results
                 if show is false, returns segmented image.
        """

        segmentation = self.predict_image(test_img)

        img_mask = np.pad(segmentation, (16, 16), mode='edge')
        ones = np.argwhere(img_mask == 1)
        twos = np.argwhere(img_mask == 2)
        threes = np.argwhere(img_mask == 3)
        fours = np.argwhere(img_mask == 4)

        test_im = mpimg.imread(test_img).astype('float')
        test_back = rgb2gray(test_im).reshape(5, 216, 160)[-2]
        # overlay = mark_boundaries(test_back, img_mask)
        gray_img = img_as_float(test_back)

        # adjust gamma of image
        image = adjust_gamma(color.gray2rgb(gray_img), 0.65)
        sliced_image = image.copy()
        red_multiplier = [1, 0.2, 0.2]
        yellow_multiplier = [1, 1, 0.25]
        green_multiplier = [0.35, 0.75, 0.25]
        blue_multiplier = [0, 0.25, 0.9]

        # change colors of segmented classes
        for i in xrange(len(ones)):
            sliced_image[ones[i][0]][ones[i][1]] = red_multiplier
        for i in xrange(len(twos)):
            sliced_image[twos[i][0]][twos[i][1]] = green_multiplier
        for i in xrange(len(threes)):
            sliced_image[threes[i][0]][threes[i][1]] = blue_multiplier
        for i in xrange(len(fours)):
            sliced_image[fours[i][0]][fours[i][1]] = yellow_multiplier

        if save:

            try:
                mkdir_p('./results/')
                io.imsave('./results/result' + '_' + str(index) + '.png', sliced_image)
            except:
                io.imsave('./results/result' + '_' + str(index) + '.png', sliced_image)
        else:
            return sliced_image

def test_adjust_gamma_greater_one():
    """Verifying the output with expected results for gamma
    correction with gamma equal to two"""
    image = np.arange(0, 255, 4, np.uint8).reshape(8,8)
    expected = np.array([[  0,   0,   0,   0,   1,   1,   2,   3],
        [  4,   5,   6,   7,   9,  10,  12,  14],
        [ 16,  18,  20,  22,  25,  27,  30,  33],
        [ 36,  39,  42,  45,  49,  52,  56,  60],
        [ 64,  68,  72,  76,  81,  85,  90,  95],
        [100, 105, 110, 116, 121, 127, 132, 138],
        [144, 150, 156, 163, 169, 176, 182, 189],
        [196, 203, 211, 218, 225, 233, 241, 249]], dtype=np.uint8)

    result = exposure.adjust_gamma(image, 2)
    assert_array_equal(result, expected)

def test_adjust_gamma_less_one():
    """Verifying the output with expected results for gamma
    correction with gamma equal to half"""
    image = np.arange(0, 255, 4, np.uint8).reshape(8,8)
    expected = np.array([[  0,  31,  45,  55,  63,  71,  78,  84],
        [ 90,  95, 100, 105, 110, 115, 119, 123],
        [127, 131, 135, 139, 142, 146, 149, 153],
        [156, 159, 162, 165, 168, 171, 174, 177],
        [180, 183, 186, 188, 191, 194, 196, 199],
        [201, 204, 206, 209, 211, 214, 216, 218],
        [221, 223, 225, 228, 230, 232, 234, 236],
        [238, 241, 243, 245, 247, 249, 251, 253]], dtype=np.uint8)

    result = exposure.adjust_gamma(image, 0.5)
    assert_array_equal(result, expected)

def augment_image(img):
    """
    Augment an image using a combination of lightening, darkening, rotation and mirror images.
    :params img: Image as numpy array
    :return: array of augmented images 
    """
    augmented_images = []
    augmented_images.append(np.fliplr(img))
    for g in [0.45, 0.65, 0.85, 1.25, 1.5, 2]:
        new_img = exposure.adjust_gamma(img, gamma=g)
        augmented_images.append(new_img)
        augmented_images.append(np.fliplr(new_img))
    new_img = transform.rotate(img, 180)
    augmented_images.append(new_img)
    augmented_images.append(np.fliplr(new_img))
    return np.array(augmented_images)