1. A system for improving foggy luminance image using fog reduction estimation model, comprising: a fog-eliminated image estimation value calculation processor receiving a foggy input image I h (x), and calculating an estimation value Ĩ(x) of fog-eliminated pixel from which the fog is removed; a transmission rate calculation processor calculating an estimation value of transmission rate {tilde over (t)}(x) and a lowest limit value of transmission rate by using the estimation value Ĩ(x) and the foggy input image I h (x), and calculating the transmission rate t(x) to be used for restoration of a fog-eliminated image I(x) by weighted sum of the estimation value of transmission rate {tilde over (t)}(x) and a lowest limit value of transmission rate; and a restoration image output processor restoring the fog-eliminated image I(x) in which the fog is removed, by using the foggy input image I h (x) and transmission rate t(x) and outputting the fog-eliminated image I(x).