PURPOSE: To measure the configurations of the front, side and back of a solid by picking up the image after shifting a phase by shift means and providing means for calculating the surface configuration of an object to be measured from a plurality of sensed images stored in memory means.
CONSTITUTION: Light beams emitted from irradiating devices 1 are irradiated on the whole surface of an object 10 to be measured via grids 5, imaging lenses 6 and parallel lenses 7 to be scattered. Scattered light is picked up by a television camera 11. Then, a picked-up zero'th image is stored in an image memory 13 in an image processor 12. Then, when the pickup of the zero'th image is terminated, pulse motors 9 are driven in synchronism with each other by a grid controller 14 in the image processor 12. The grids 5 of the devices 1 are uniformly shifted by a phase π/2. Thereafter, a first image is picked up by the camera 11 and stored in the memory 13. Thereafter, similarly, the phases of the grids 5 of the devices 5 are shifted by π and 3π/2 and second and third images are stored.After picking up all the four images is terminated, a phase distribution ϕ is calculated by the image processor 12 and displayed on a monitor 15 as a phase picture.