The company that measures television viewing said Wednesday it will roll out new technology during the next few years to measure viewing over the Internet, on cell phones and on TV sets outside of the home.

Nielsen Media Research said the technology supplements its recent effort to figure the use of digital video recorders in its weekly TV ratings.

Television's entire economic system of advertising prices is based on Nielsen's ratings, and its customers have long grumbled that the company hasn't kept up with technology that is changing the way people are watching TV.

Nielsen said that this summer it will begin testing software meters on personal and home computers of participating families, designed to measure the video and audio they are watching via the Internet. The company said its goal is to have accurate readings of how many people are watching television content this way by the 2007-08 season.

The company said that this fall it will also begin testing two separate "go meters," one designed to measure viewing of video on cellular phones, and the other to keep track of viewing outside of the home in bars, restaurants, hotels and elsewhere.

Nielsen said its engineers were also developing new meters that, in the future, will be able to be used with any portable media system. It hopes to begin testing late next year.

"As digital distribution of television transforms the way our clients do business, Nielsen is keeping pace with new ways of measuring TV wherever it is viewed," said Susan D. Whiting, president and chief executive officer of Nielsen Media Research.