Method and apparatus for monitoring TV channel selecting status

A TV channel selecting status monitoring system which identifies a channel being actually received by a TV which has at least one built-in digital tuner, provides video and audio signals of the channel selected by said built-in digital tuner to a display and a loudspeaker, respectively, and has a digital audio output terminal through which to output a digital audio signal of said selected channel, said system comprising:

• a terminal device connected to said TV;
• and
• a center apparatus capable of communicating with said terminal device;
• wherein said terminal device comprises:
• a viewing block data generating part which detects a change of audio data-type by analyzing a preamble of a data-burst generated from said digital audio signal output from said digital audio output terminal of said TV, and for each viewing period from the time of the change of audio data-type to the time of the next change of audio data-type, generates viewing block data containing comparison feature data extracted from said data-burst within said viewing period and containing time data on said viewing period;
• a storage part for storing said generated viewing block data;
• and
• a communication part for transmitting said viewing block data stored in said storage part to said center apparatus;
• and
• wherein said center apparatus comprises;
• a comparison data storage part for storing said viewing block data transmitted from said terminal device;
• a reference data storage part for storing, for each channel monitored for identification, reference data containing reference feature data extracted from a data-burst generated from the digital audio signal of said channel concerned and time data of said data-burst;
• and
• a channel decision processing part for making a decision, for each viewing block data stored in said comparison data storage part, on the channel being monitored for identification by making a comparison between feature data contained in said viewing block data and reference feature data contained in reference data on each channel stored in said reference data storage part.

A terminal device comprising:

• a viewing block data generating part which detects a change of audio data-type by analyzing a preamble of a data-burst generated from a digital audio signal output from a digital audio output terminal of a TV, and for each viewing period from the time of the change of audio data-type to the time of the next change of audio data-type identifying part, generates viewing block data containing comparison feature data extracted from a data-burst within said viewing period and containing time data on said viewing period;
• a storage part for storing said generated viewing block data;
• and
• a communication part for transmitting said viewing block data stored in said storage part to a center apparatus.

A center apparatus comprising:

• a comparison data storage part for receiving from a terminal device and storing viewing block data containing comparison feature data extracted from a data-burst generated from a digital audio signal of a TV within a viewing period from the start to the end of tuning of said TV to the same channel and containing time data of said viewing period;
• a reference data storage part for storing, for each channel monitored for identification, reference data containing reference feature data extracted from a data-burst generated from the digital audio signal of said channel concerned and time data of said data-burst;
• and
• a channel decision processing part for making a decision, for each viewing block data stored in said comparison data storage part, on the channel being monitored for identification by making a comparison between feature data contained in said viewing block data and reference feature data contained in reference data on each channel stored in said reference data storage part.