TY  - RPRT
TI  - Image gradient evolution - a visual cue for danger 
AU  - Liu, Hongche
AU  - Hong, Tsai-Hong
AU  - Herman, Martin
AU  - Chellappa, Rama
PY  - 1995
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - NIST IR 5728
DO  - 10.6028/NIST.IR.5728
ER  -