Add Image Resizing and Colab Support

Fixes qubvel#412 : Resizing Images to avoid errors
Fixes Colab Bug : Using Segmentation Models

examples/binary segmentation (camvid).ipynb

@@ -110,13 +110,21 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "\"\"\"\n",
+    "If dataset needs to be resized use these values MAIN_SIZE_X,MAIN_SIZE_Y = 512,512 else put MAIN_SIZE_X,MAIN_SIZE_Y = None,None\n",
+    "\"\"\"\n",
+    "MAIN_SIZE_X,MAIN_SIZE_Y = None,None\n",
+    "\n",
+    "\n",
+    "\n",
     "# helper function for data visualization\n",
     "def visualize(**images):\n",
     "    \"\"\"PLot images in one row.\"\"\"\n",
     "    n = len(images)\n",
-    "    plt.figure(figsize=(16, 5))\n",
+    "    plt.figure(figsize=(20, 12))\n",
     "    for i, (name, image) in enumerate(images.items()):\n",
     "        plt.subplot(1, n, i + 1)\n",
+    "        plt.axis('off')\n",
     "        plt.xticks([])\n",
     "        plt.yticks([])\n",
     "        plt.title(' '.join(name.split('_')).title())\n",
@@ -175,7 +183,11 @@
     "        # read data\n",
     "        image = cv2.imread(self.images_fps[i])\n",
     "        image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)\n",
+    "        if MAIN_SIZE_X,MAIN_SIZE_Y == None,None:\n",
+    "          image = cv2.resize(image,(MAIN_SIZE_Y,MAIN_SIZE_X))\n",
     "        mask = cv2.imread(self.masks_fps[i], 0)\n",
+    "        if MAIN_SIZE_X,MAIN_SIZE_Y == None,None:\n",
+    "          mask = cv2.resize(mask,(MAIN_SIZE_Y,MAIN_SIZE_X))\n",
     "        \n",
     "        # extract certain classes from mask (e.g. cars)\n",
     "        masks = [(mask == v) for v in self.class_values]\n",
@@ -216,7 +228,6 @@
     "        self.batch_size = batch_size\n",
     "        self.shuffle = shuffle\n",
     "        self.indexes = np.arange(len(dataset))\n",
-    "\n",
     "        self.on_epoch_end()\n",
     "\n",
     "    def __getitem__(self, i):\n",
@@ -230,8 +241,8 @@
     "        \n",
     "        # transpose list of lists\n",
     "        batch = [np.stack(samples, axis=0) for samples in zip(*data)]\n",
-    "        \n",
-    "        return batch\n",
+    "        return tuple(batch)\n",
+    "\n",
     "    \n",
     "    def __len__(self):\n",
     "        \"\"\"Denotes the number of batches per epoch\"\"\"\n",
@@ -447,6 +458,10 @@
     }
    ],
    "source": [
+    "\"\"\"\n",
+    "While Using in Colab Use\n",
+    "%env SM_FRAMEWORK=tf.keras\n",
+    "\"\"\"\n",
     "import segmentation_models as sm\n",
     "\n",
     "# segmentation_models could also use `tf.keras` if you do not have Keras installed\n",