Temperature (color) maps derived using the Eq. (1) of IRAS 15534−5422, IRAS 17009−4154, IRAS 18229−1127 and IRAS 18454−18454. We note that the red patches at the borders of the color the maps of IRAS 17009−4154 and IRAS 18454+0001 are artifacts caused by the reduced S/N in the outermost regions of these sources. The central stars of IRAS 17009−4154 and IRAS 18229−1127 have been masked to construct the color maps.