Terahertz　waves　have　unique　propagation　and　penetration　ability,　and　these　reasons　have　been　widely　used　in　nondestructive　testing.　Compared　with　other　terahertz　imaging　approaches,　terahertz　digital　holography　can　retrieve　both　quantitative　amplitude　and　phase　information　about　an　object　wavefront　in　real　time.　A　continuous-wave　terahertz　reflective　digital　holographic　method　is　proposed　for　measuring　the　profile　of　covered　objects.　Subpixel　image　registration　and　image　fusion　algorithms　are　presented　to　expand　the　field-of-view　(FOV)　of　the　system.　The　validity　of　the　proposed　method　is　verified　by　the　experiment　using　an　optical　pumped　far-IR　gas　laser　and　a　pyroelectric　array　detector.　The　profile　of　a　metallic　bookmark　covered　by　a　polytetrafluoroethylene　plate　is　obtained.　The　FOV　is　expanded　by　a　factor　of　1.75　compared　with　that　of　a　reconstruction　performed　employing　single　hologram.　(C)　2019　Society　of　Photo-Optical　Instrumentation　Engineers　(SPIE)