Fix total loss calculation, add some more todos

unsupervised/train.py

@@ -55,6 +55,7 @@ class UnsupervisedPoseDepthLearner(keras.Model):
             #   It isn't too much of an issue right now since we're only using 2 images (left/right)
             # For each depth output (scale), do the projective inverse warp on each input image and calculate the losses
             # Only take the min loss between the two warped images (from monodepth2)
+            # TODO: Need to bilinear resize the depth at each scale up to the size of image
             warp1 = warp.projective_inverse_warp(data.frames[0], depth[scale], pose1, data.intrinsics, coords)
             warp2 = warp.projective_inverse_warp(data.frames[2], depth[scale], pose1, data.intrinsics, coords)
 
@@ -73,13 +74,17 @@ class UnsupervisedPoseDepthLearner(keras.Model):
                 tf.reduce_min(tf.concat([warp_loss1, warp_loss2, source_loss1, source_loss2], axis=3), axis=3))
 
             # Calculate smooth losses
+            # TODO: Since smooth loss is calculated directly on the depth at the scale, we need
+            #  to resize the target image to the same dimensions as the depth map at the current scale
+            #  Can do this by just inspecting the shape of the depth and resizing to match that (but
+            #  with 3 colour channels)
             smooth_loss = loss.smooth_loss(depth[scale], data.frames[1])
 
-            # TODO: Monodepth also divides the smooth loss by 2 ** scale, why?
+            # SFM Learner downscales smoothing loss depending on the scale
             smoothed_reprojection_loss = self.smoothness * smooth_loss / (2 ** scale)
 
             # Add to total loss (with smooth loss + smooth loss weighting applied to pixel losses)
-            total_loss += reprojection_loss + smooth_loss
+            total_loss += reprojection_loss + smoothed_reprojection_loss
             pass
 
         # Collect losses, average them out (divide by number of scales)