For scanning active imaging systems using direct detection, it is poss
ible to adequately model the expected speckle noise. Modifications are
introduced to the theory on speckle originally proposed by Goodman to
take into account the scanning effect. The model presented here is ve
rified experimentally for a scanning active imaging system using a CO2
laser (10.6 mum). A direct relation between the reduction in the spec
kle noise resulting from the scanning process and the imaging resoluti
on is demonstrated.