Update image_reader.py

Author: hellochick

utils/image_reader.py

@@ -100,6 +100,7 @@ def _random_crop_and_pad_image_and_labels(image, label, crop_h, crop_w, ignore_l
     combined_crop = tf.random_crop(combined_pad, [crop_h, crop_w, 4])
     img_crop = combined_crop[:, :, :last_image_dim]
     label_crop = combined_crop[:, :, last_image_dim:]
+    label_crop = label_crop + ignore_label
     label_crop = tf.cast(label_crop, dtype=tf.uint8)
 
     # Set static shape so that tensorflow knows shape at compile time.