Lorentz Transform of Black Body Radiation Temperature

The Lorentz transform of black body radiation has been investigated from the view point of relativistic statistical mechanics. The result shows that the well known expression with the directional temperature can be derived based on the inverse temperature four vector. The directional temperature in the past literature was the result of mathematical manipulation and its physical meaning is not clear. The inverse temperature four vector has, in contrast, clear meaning to understand relativistic thermodynamical processes.