The Internet of Things is playing an important role, organizing all things that use data and connecting them to the Internet. It has been made possible by the rapid progress in smart and real-time measurement technologies, the miniaturization and speeding up of sensor technologies as well as intelligent data processors, and by the spread of cloud technology, which accumulates huge amounts of data. To establish smart and precision manufacturing, not only the improvement of conventional ultraprecision machining techniques but also the development of the novel, high-performance machining techniques has been made. On-machine and in-process measurement are gaining in importance for emerging machining technologies as well as conventional ones. Advanced techniques of machining and metrology as well as feedback for compensation manufacturing have been required for plasticity to on-machine and in-process conditions.

This special issue focuses on metrology and manufacturing measurement and instrumentation for the progress of state-of-the-art on-machine and in-process measurement systems and sensor technologies. It consists of contributions related to, but not limited to, the following topics:

- On-machine, in-process measurement and process monitoring

- Practical application of on-machine, in-process measurement

- Machine tool metrology

- Intelligent micro- and nano-metrology

- Multi-sensor fusion and multi-sensor cooperation

- Form and dimensional measurement and instrumentation

- 3D-surface texture and its micro-characteristics

- Machine learning, AI aided measurement

We would like to sincerely thank all the authors for their contributions, and we sincerely hope that the papers in this special issue further contribute to the development of our future society from a new horizon of metrology.