Visual inspection (VT)
Visual inspection is a primary method of non-destructive testing (NDT). Many others NDT methods require visual inspection to reveal and assess imperfections. This method is simple, easy to apply, quickly carried out and usually low in cost. Visual testing (VT) usually is conducted with a naked eye, but it can be enhanced with the use of optical instruments such as magnifying glasses, mirrors and borescopes. Generally, almost any specimen can be visually examined to determine the accuracy of its fabrication. Physical damage, misalignment of parts, corrosion, pores and cracks are just some of the discontinuities that may be detected by visual examinations.