Refine train.py for MobileNet-SSD.

fluid/object_detection/image_util.py

@@ -216,7 +216,7 @@ def distort_image(img, settings):
 
 def expand_image(img, bbox_labels, img_width, img_height, settings):
     prob = random.uniform(0, 1)
-    if prob < settings._hue_prob:
+    if prob < settings._expand_prob:
         expand_ratio = random.uniform(1, settings._expand_max_ratio)
         if expand_ratio - 1 >= 0.01:
             height = int(img_height * expand_ratio)

fluid/object_detection/train.py

@@ -50,11 +50,12 @@ def train(args,
                                          box, box_var)
             nmsed_out = fluid.layers.detection_output(
                 locs, confs, box, box_var, nms_threshold=0.45)
+            loss = fluid.layers.reduce_sum(loss)
             pd.write_output(loss)
             pd.write_output(nmsed_out)
 
         loss, nmsed_out = pd()
-        loss = fluid.layers.reduce_sum(loss)
+        loss = fluid.layers.mean(loss)
     else:
         locs, confs, box, box_var = mobile_net(image, image_shape)
         nmsed_out = fluid.layers.detection_output(