Measuring device and system

The invention provides a measuring device and system. The measuring device comprises a first light source emitter used for generating a first light beam and emitting the first light beam to a first modulator; a second light source emitter used for generating a second light beam and emitting the second light beam to the first modulator, wherein the wavelength of the first light beam is different from that of the second light beam; the first modulator used for mixing the first light beam with the second light beam to form a mixed light beam and transmitting the mixed light beam to a flow field test section; a second modulator used for receiving the mixed light beam after passing through the flow field test section, dispersing the mixed light beam into the first light beam and the second light beam so that the first light beam passes through a first knife edge to enter a camera and the second light beam passes through the second knife edge to enter a video camera; the camera used for forming a shadow image of th