An extrusion construction system may include an extrusion nozzle, a channeling element coupled to the extrusion nozzle and to a source of construction material, the channeling element configured to transport the material to the extrusion nozzle for extruding the material onto a surface, wherein a surface of the channeling element comprises a transparent substrate such that a flow of the material is viewable through the substrate, an imaging device configured to capture a plurality of images through the substrate of the material flow, and a controller configured to estimate a flow rate based on the plurality of images.