NHK researchers built a UHDTV prototype which they demonstrated in 2003. They used an array of 16 HDTV recorders with a total capacity of almost 3. 5 TB that could capture up to 18 minutes of test footage. The camera itself was built with four 2. 5 inch (64 mm) CCDs, each with a resolution of only 3840×2048. Using two CCDs for green and one each for red and blue, they then used a spatial pixel offset method to bring it to 7680×4320. [a] Subsequently, an improved and more compact system was built using CMOS image sensor technology and the CMOS image sensor system was demonstrated at Expo 2005, Aichi, Japan, the NAB 2006 and NAB 2007 conferences, Las Vegas, at IBC 2006 and IBC 2008, Amsterdam, Netherlands, and CES 2009. A review of the NAB 2006 demo was published in a Broadcast Engineering e-newsletter. Individuals at NHK and elsewhere projected that the timeframe for UHDTV to be available in domestic homes varied between 2015 and 2020 but Japan was to get it in the 2016 time frame.