Fig. 7. part visual retrieval results including walk, run, jump, cartwheel, swing from
upper to lower.
− On the other hand, time cost of approach is evaluated in ours work. The
time cost includes two main parts: feature vectors extraction and
computation of HSN covering. A main time-consuming operation is feature
vectors extraction for the whole database (about 2 minutes) and the
operation needs to be executed only one time in all experiments because
the structures of feature vectors are same and uniform for different retrieval
instances. Moreover, the time cost of covering computation traversing the
whole database about for a retrieval instance is about 25 seconds.