1. A parcel dimension measurement system comprising: line scan cameras oriented to image a parcel having six faces or sides as said parcel is transported through a shipping or sorting tunnel system; an imaging subsystem configured to stitch together outputs of the line scan cameras to produce a two-dimensional image of at least one face or side of said parcel, said two-dimensional image comprised of a plurality of pixels; a general dimension subsystem including general parcel dimension information; and a fine dimensioning subsystem configured to include line scanning to determine dimension measurements of said at least one face of the parcel using the two-dimensional image and the general parcel dimension information.