A noise level estimation module includes a pixel block selection module for selecting a plurality of selected pixel blocks over a set of K fields of a video signal, each of the plurality of selected pixel blocks containing a plurality of pixels having corresponding pixel values. In the power transmission apparatus, the power supplied to the non-contact power receiving apparatus is measured, and the output power of the wireless power signal output from two different cores is controlled, thereby allowing the charging operation to be stably conducted even if the non-contact power receiving apparatus is moved anywhere on the power transmission apparatus. The web page is updated automatically based at least in part on an indication that the stored object has been changed.