Disclosed herein are techniques and systems for evaluating exercise performance of a user by utilizing one or more intelligent sensors, including at least one camera-based sensor configured to detect image data of the user. The vector of metrics of the bits considered at the output of the demodulator is decoded. The shift is then performed by selecting the appropriate bits from the input line to create the result. As a node forwards a publication to another node, it is required to append its own UUID to this list or discard the message if its UUID already is in the attached list. The methods effectively represent the characteristics of a color histogram of an image in comparison to conventional art, and improve the performance of image retrieval when an image retrieval search is conducted.