" The Asakusa Samba Carnival is held annually, on a Saturday towards the end of August, in Asakusa, Tokyo. Attracting about 500,000 sightseers who fall under the spell of the passionate rhythms of the samba, the event has a strong international flavor.
As a town that grew up around a temple, Asakusa observes many traditional festivals, but the Samba Carnival, which started in 1981, is a new event. It started when the Mayor of Taito City (one of the central 23 cities of Tokyo) invited the winning group from that year's Rio Carnival in Brazil, the home of the samba, to put on a display.
The main attraction of the festival is the samba parade contest.
Together with samba teams from the carnival homeland of Brazil, about 3,500 lovers of samba rhythms come from all over Japan. These teams compete to put on the most spectacular dancing and other performances, creating a carnival that is just as wonderful as the one in Rio. Bright eye-catching costumes with beads and plumes of different colors also provide a visual feast. There are also plenty of ingenious devices that embody original ideas, including flower-decked floats on motor vehicles and allegoria handcarts with sound systems."Source: http://web-japan.org/atlas/festivals/fes11.html
for better pics, you may check Totomai's page.