support image normalization

README.md

@@ -148,5 +148,7 @@ Examples:
     This runs on GPU a basic 4-layers fully connected neural network on the Pavia University dataset, using 10% of the samples for training.
   * `python main.py --model hamida --dataset PaviaU --training_sample 0.5 --patch_size 7 --epoch 50 --cuda`
     This runs on GPU the 3D CNN from Hamida et al. on the Pavia University dataset with a patch size of 7, using 50% of the samples for training and optimizing for 50 epochs.
+  * `python main.py --model li --dataset IndianPines --training_sample 0.5 --normalization SNB --cuda`
+    This runs on GPU the 3D CNN from Li et al. on the Indian Pines dataset with the default patch size of 5, using 50% of the samples for training with the SNB Normalization method.
 
 [![Say Thanks!](https://img.shields.io/badge/Say%20Thanks-!-1EAEDB.svg)](https://saythanks.io/to/nshaud)

datasets.py

@@ -18,7 +18,7 @@
     # Python 2
     from urllib import urlretrieve
 
-from utils import open_file
+from utils import open_file, normalise_image
 
 DATASETS_CONFIG = {
     "PaviaC": {
@@ -96,7 +96,7 @@ def update_to(self, b=1, bsize=1, tsize=None):
         self.update(b * bsize - self.n)  # will also set self.n = b * bsize
 
 
-def get_dataset(dataset_name, target_folder="./", datasets=DATASETS_CONFIG):
+def get_dataset(dataset_name, normalization_method="MNI", target_folder="./", datasets=DATASETS_CONFIG):
     """Gets the dataset specified by name and return the related components.
     Args:
         dataset_name: string with the name of the dataset
@@ -303,6 +303,10 @@ def get_dataset(dataset_name, target_folder="./", datasets=DATASETS_CONFIG):
             palette,
         ) = CUSTOM_DATASETS_CONFIG[dataset_name]["loader"](folder)
 
+    # Normalization
+    img = np.asarray(img, dtype="float32")
+    img = normalise_image(img, method=normalization_method)
+
     # Filter NaN out
     nan_mask = np.isnan(img.sum(axis=-1))
     if np.count_nonzero(nan_mask) > 0:
@@ -312,11 +316,8 @@ def get_dataset(dataset_name, target_folder="./", datasets=DATASETS_CONFIG):
     img[nan_mask] = 0
     gt[nan_mask] = 0
     ignored_labels.append(0)
-
     ignored_labels = list(set(ignored_labels))
-    # Normalization
-    img = np.asarray(img, dtype="float32")
-    img = (img - np.min(img)) / (np.max(img) - np.min(img))
+
     return img, gt, label_values, ignored_labels, rgb_bands, palette
 
 

main.py

@@ -129,6 +129,19 @@
     help="Path to the test set (optional, by default "
     "the test_set is the entire ground truth minus the training)",
 )
+group_dataset.add_argument(
+    "--normalization",
+    type=str,
+    default='MNI',
+    help="Normalization method to use for image preprocessing. Available:\n"
+    "None: Applying none preprocessing."
+    "L2NS: Normalizing with a unit Euclidean norm along each sample."
+    "MNB: Converting the dynamics to [0, 1] along each band."
+    "SNB: Normalizing first- and second-order moments along each band."
+    "MNI: Converting the dynamics to [0, 1] along the whole image."
+    "SNI: Normalizing first- and second-order moments along the whole image.",
+)
+
 # Training options
 group_train = parser.add_argument_group("Training")
 group_train.add_argument(
@@ -225,6 +238,8 @@
 # Testing ground truth file
 TEST_GT = args.test_set
 TEST_STRIDE = args.test_stride
+# Normalization method
+NORM_METHOD = args.normalization
 
 if args.download is not None and len(args.download) > 0:
     for dataset in args.download:
@@ -238,7 +253,7 @@
 
 hyperparams = vars(args)
 # Load the dataset
-img, gt, LABEL_VALUES, IGNORED_LABELS, RGB_BANDS, palette = get_dataset(DATASET, FOLDER)
+img, gt, LABEL_VALUES, IGNORED_LABELS, RGB_BANDS, palette = get_dataset(DATASET, NORM_METHOD, FOLDER)
 # Number of classes
 N_CLASSES = len(LABEL_VALUES)
 # Number of bands (last dimension of the image tensor)

utils.py

@@ -222,9 +222,52 @@ def get_random_pos(img, window_shape):
     return x1, x2, y1, y2
 
 
-def padding_image(image, patch_size=None, mode="symmetric", constant_values=0):
+def normalise_image(image, method='None', epsilon=1e-7):
+    """Normalise an image.
+
+    Args:
+        image: A 3D image with a shape of [h, w, b] or 2D image with a shape of [h * w, b],
+        The array to pad
+        method: optional, used to normalise a HSI, default is None,
+        including six categories as follows:
+        1) None: Applying none preprocessing.
+        2) L2NS: Normalizing with a unit Euclidean norm along each sample.
+        3) MNB: Converting the dynamics to [0, 1] along each band.
+        4) SNB: Normalizing first- and second-order moments along each band.
+        5) MNI: Converting the dynamics to [0, 1] along the whole image.
+        6) SNI: Normalizing first- and second-order moments along the whole image.
+        epsilon: optional, default is 1e-7, small float added to variance to avoid dividing by zero.
+    Returns:
+        normalised_image with the same shape of the input
+
+    """
+    allowed_methods = ['NONE', 'L2NS', 'MNB', 'SNB', 'MNI', 'SNI']
+    method = method.upper()
+    if method not in allowed_methods:
+        raise ValueError('unknown normalization method "%s"' % (method,))
+
+    shp = image.shape
+    if len(shp) >= 3:
+        image = image.reshape(-1, shp[-1])
+
+    if method == 'L2NS':
+        image = image / (np.linalg.norm(image, axis=1, keepdims=True) + epsilon)
+    elif method == 'MNB':
+        image = (image - np.min(image, axis=0, keepdims=True)) / \
+              (np.max(image, axis=0, keepdims=True) - np.min(image, axis=0, keepdims=True) + epsilon)
+    elif method == 'SNB':
+        image = (image - np.mean(image, axis=0, keepdims=True)) / (np.std(image, axis=0, keepdims=True) + epsilon)
+    elif method == 'MNI':
+        image = (image - np.min(image, axis=(0, 1), keepdims=True)) / \
+              (np.max(image, axis=(0, 1), keepdims=True) - np.min(image, axis=(0, 1), keepdims=True) + epsilon)
+    elif method == 'SNI':
+        image = (image - np.mean(image, axis=(0, 1), keepdims=True)) / (np.std(image, axis=(0, 1), keepdims=True) + epsilon)
+
+    return np.reshape(image, shp)
+
+
+def padding_image(image, patch_size=None, mode="symmetric", **kwargs):
     """Padding an input image.
-    Modified at 2020.11.16. If you find any issues, please email at mengxue_zhang@hhu.edu.cn with details.
 
     Args:
         image: 2D+ image with a shape of [h, w, ...],
@@ -233,8 +276,6 @@ def padding_image(image, patch_size=None, mode="symmetric", constant_values=0):
         The patch size of the algorithm
         mode: optional, str or function, default is "symmetric",
         Including 'constant', 'reflect', 'symmetric', more details see np.pad()
-        constant_values: optional, sequence or scalar, default is 0,
-        Used in 'constant'.  The values to set the padded values for each axis
     Returns:
         padded_image with a shape of [h + patch_size[0] // 2 * 2, w + patch_size[1] // 2 * 2, ...]
 
@@ -245,7 +286,7 @@ def padding_image(image, patch_size=None, mode="symmetric", constant_values=0):
     w = patch_size[1] // 2
     pad_width = [[h, h], [w, w]]
     [pad_width.append([0, 0]) for i in image.shape[2:]]
-    padded_image = np.pad(image, pad_width, mode=mode, constant_values=constant_values)
+    padded_image = np.pad(image, pad_width, mode=mode, **kwargs)
     return padded_image