improve the following passage:

Although ELIA achieves impressive overall performance for referring image segmentation, its segmentation accuracy at the object  boundaries still has some room for improvements. As shown in NAME_1. \ref{failure}, when the objects are occluded or have unclear boundaries, ELIA's predicted masks might miss some target pixels or spill over to other objects. This problem can be attributed to a lack of boundary supervision and relatively low mask annotation quality in the training datasets. We anticipate future work to further improve referring image segmentation from by tackling these issues. I want the entire output in JSON format.
user