Abstract: A measurement method for selecting a rectangle from a grid image that has been projected on a surface of an object or that has been gained by taking an image of a grid drawn on the surface of an object, inputting an image in a state where the optical system has been adjusted in such a manner that the grid phase of the above-described projected grid image or the above-described drawn grid is gained by dividing 2m? (m is an integer) by Mx×Ny within the rectangle, sampling a rectangular region made up of Mx pixels in the x direction and Ny pixels in the y direction of the above-described grid image or an image of the above-described grid from the above-described inputted image, and finding a phase on the basis of the brightness of pixels in the above-described rectangular region.

Abstract: A phase of a specific frequency component of an image of a grid image on the surface of an object taken by a camera is found, and the location of the surface of the object is found from the phase. As a result, measurement that is strong against noise can be carried out without projecting a grid having a brightness distribution of precise cosine waves. In addition, the process is simple and can be used for the surface of a moving object. The number of pixels used for the measurement is smaller than that in the sampling moire method.

Abstract: A phase of a specific frequency component of an image of a grid image on the surface of an object taken by a camera is found, and the location of the surface of the object is found from the phase. As a result, measurement that is strong against noise can be carried out without projecting a grid having a brightness distribution of precise cosine waves. In addition, the process is simple and can be used for the surface of a moving object. The number of pixels used for the measurement is smaller than that in the sampling moire method.

Abstract: A measurement method according to which: an image of a grid projected on a reference plane is taken; the optical system is adjusted so that the phase of the projected grid is gained by dividing 2m? (m is an integer) by Mx×Ny (=M) (Mx and Ny are an integer of 2 or greater) within a rectangle made up of Mx pixels in the x direction and Ny pixels in the y direction of the image gained by taking an image of the grid projected on the above-described reference plane; an image is taken of a grid pattern projected on an object placed on the above-described reference plane; the brightness value is found by dividing 2m? by Mx×Ny in a rectangular region of Mx×Ny pixels made up of Mx pixels in the x direction and Ny pixels in the y direction of the image gained by taking an image of the grid pattern projected on said object; a phase is found using said brightness value; an image is taken of the grid pattern projected on the object placed on the above-described reference plane; the above-described phase is found by shifti

Abstract: A phase of a specific frequency is found by carrying out a two-dimensional Fourier transformation on an image of a two-dimensional grid image on the surface of an object taken by a camera, and the displacement of the surface of the object is measured from the phase. As a result, measurement that is strong against noise can be carried out without projecting a grid having a brightness distribution of precise cosine waves. In addition, the process is simple and the number of pixels used for the measurement is smaller than that in the sampling moire method. The displacement can be found at a high speed.

Abstract: A phase of a specific frequency is found by carrying out a two-dimensional Fourier transformation on an image of a two-dimensional grid image on the surface of an object taken by a camera, and the displacement of the surface of the object is measured from the phase. As a result, measurement that is strong against noise can be carried out without projecting a grid having a brightness distribution of precise cosine waves. In addition, the process is simple and the number of pixels used for the measurement is smaller than that in the sampling moire method. The displacement can be found at a high speed.