电子科发女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 2.Log Transformations L-1 Negative nth root s clog(r+1) 3L/4 where c is a constant,and nth power it is assumed that r>0 Lp L/4 Identity Inverse log 0 L/4 LR 3L4 L-1 Input intensity level,r2. Log Transformations s c r = + log( 1) ◼ where c is a constant, and it is assumed that r≥0