Hidefumi Kobatake Yoshiaki Inoue Tatsuro Namai Nobuhiro Hamba Measurement of two-dimensional movement of traffic by image processing. 614-617 1987 ICASSP https://doi.org/10.1109/ICASSP.1987.1169643 conf/icassp/1987 db/conf/icassp/icassp1987.html#KobatakeINH87