Nielsen plans to roll out a new service to measure TV viewers outside of the home. Coverage will start in September in six major U.S. cities, including Los Angeles.

The service will attempt to estimate TV audiences in locations such as offices, fitness clubs, hotels and bars. The six cities will each have a panel of typical TV viewers with approximately 500 people. The sample for the national service will be comprised of a portion of participants from the local services, plus an additional 1,700 national panelists to provide a greater representation of the rest of the U.S.

Panel participants will carry a mobile phone that includes metering technology developed by Integrated Media Measurement Inc., or Immi, based in San Mateo. The special phones collect passive digital signatures from television telecasts that Immi will match with audio signatures collected by Immi from actual telecasts. The signatures will be transmitted to Immi computer servers for reporting.