The use of numerical procedure at a level never reach so far in optical imaging enables DHM to overcome two cumbersome alignment procedures of interferometric microscopes: (1) fine focus of the sample, and (2) sample tilt adjustment. In addition the technology enables to retrieve the full information from a single hologram acquisition. This enables very short acquisition time, smaller than typical propagation frequencies of ambient vibrations. These instruments can be operated without vibration insulation tables. Combined with the simplicity of the opto-mechanical design and the absence of moving parts, DHM are new measurement systems with a nanometer scale resolution ready to take place in production lines. DHM can be used to characterized shapes and surface roughness of a large variety of samples and their use for industrial inspection should definitely spread during the next years