With the digital shadow technology,reference image and deformed image are captured by CCD and saved in computer.Then the information of the object can be obtained through Fourier transform of the two images.The measurement has a high level of automation.Especially the fringes are sinusoidal patterns and the spatial line pitch can be optionally adjusted,which are more precious compared with the grating-projected fringes.The devices are common and the demand for environment is low.The results proved that the system has higher precision and further applications because of its simplicity.