Refactor load/util, start fixing packnet to support NHWC format

util.py

@@ -0,0 +1,21 @@
+import tensorflow as tf
+import tensorflow.keras as keras
+
+
+def crop_and_resize(x, out_shape=(224, 224)):
+    shape = tf.shape(x['depth'])
+    img_shape = tf.shape(x['image'])
+    # Ensure we get a square for when we resize is later.
+    # For horizontal images this is basically just cropping the sides off
+    center_shape = min(shape[1], shape[2], img_shape[1], img_shape[2])
+
+    def layer():
+        return keras.Sequential([
+            keras.layers.experimental.preprocessing.CenterCrop(
+                center_shape, center_shape),
+            keras.layers.experimental.preprocessing.Resizing(
+                out_shape[0], out_shape[1], interpolation='nearest')
+        ])
+
+    # Reshape label to 4d, can't use array unwrap as it's unsupported by tensorflow
+    return layer()(x['image']), layer()(tf.reshape(x['depth'], [shape[0], shape[1], shape[2], 1]))