The　pursuit　of　high-resolution,　high-fidelity,　real-time　imaging　is　receiving　significant　attention　in　terahertz　community.　In　this　study,　a　versatile　illumination　approach　based　on　a　double-mirror　galvanometer　is　proposed　and　optimized　for　multiple　terahertz　imaging　approaches.　We　analyzed　the　mechanism　of　galvanometric　illumination　and　elucidated　two　main　factors　affecting　its　homogeneity　and　parallelism　properties.　In　our　module,　the　terahertz　beam　is　deflected　rapidly　by　the　galvanometer　which　is　driven　by　triangular　voltage　signals,　and　then　focused　by　a　self-designed　aspherical　f-theta　lens　to　illuminate　the　object　at　an　equal　lateral　scanning　velocity.　The　object　beam　of　different　transients　is　periodically　superimposed　along　the　Lissajous　trajectory,　and　is　recorded　by　an　array　microbolometer　in　a　single　integration　of　3　s.　A　homogeneous　illumination　field　is　realized　with　a　speckle　contrast　of　0.11,　and　the　resultant　image　achieves　isotropic　resolution.　By　adopting　the　proposed　galvanometric　illumination　strategy,　the　average　intensity　of　the　illumination　field　is　increased　by　135%　compared　to　expanded　coherent　illumination,　and　the　speckle　contrast　is　reduced　by　83.5%　compared　to　other　galvanometric　illumination.　By　virtue　of　leading　low　speckle　noise,　illumination　homogeneity　and　parallelism,　a　compact　imaging　system　is　built　for　terahertz　full-field　imaging　and　computed　tomography　achieving　high　imaging　speed　and　fidelity.　As　a　successful　attestation　of　terahertz　beam　steering,　this　study　is　very　promising　to　reduce　the　total　cost,　increase　the　performance　and　expand　the　application　of　terahertz　imaging.