An optical device used to project images onto a surface, similar to a slide projector but usually for level projection of transparencies or documents; also called 投影机tóuyǐngjī or 投影器tóuyǐngqì
optical comparator
A measuring instrument that applies the principles of light projection to inspect the shapes and sizes of complex workpieces, templates, or tools
photogrammetric plotter
An instrument used to transfer data from drawings or maps onto a compilation sheet using light reflection
