Abstract: A surveying target sphere for use in a three-dimensional measurement has a spherical surface having a constant radius from a center and includes a north pole, a south pole, and a central axis passing through the center of the surveying target sphere and linking the north pole and the south pole, and a level is mounted at the north pole.

Abstract: A surveying target sphere for use in a three-dimensional measurement has a spherical surface having a constant radius from a center and includes a north pole, a south pole, and a central axis passing through the center of the surveying target sphere and linking the north pole and the south pole, and a level is mounted at the north pole.

Abstract: When a three-dimensional laser scanning device is used at a civil engineering construction site, a point cloud density of laser beam per unit area is greatly different between a nearby area of the device and a far end, which increases the number of measurement and the amount of time for measurement to satisfy the accuracy of distance measurement. In the three-dimensional laser scanning device, an axis around which a body rotates or rotatably moves is tilted to intersect with a direction perpendicular to a measurement surface. A control unit gradually reduces an angular velocity of the rotation or the rotatable movement of the body around the axis with an increase of a distance to the measurement point to keep the point cloud density of laser beam projected onto the measurement surface constant.

Abstract: A survey method comprises a first step for obtaining coordinates of first to fourth points on a wall surface; a second step for specifying first to fourth surfaces; a third step for obtaining distances ?4, ?1, ?2, ?3; a fourth step for determining a largest value ?max among the first to fourth distances ?1 to ?4 as an evaluation value; and a fifth step of defining any of the first to fourth surfaces as a specific surface specifying the wall surface if the evaluation value ?max is less than a predetermined threshold value ?th.

Abstract: Disclosed herein is an optical device that determines the central coordinates of a large-diameter cylindrical structure. The optical device has the function of calculating the central coordinates of a cylindrical structure using the coordinates of a reference point of the optical device, the coordinates of a survey point on the cylindrical structure seen on the optical axis of a telescope in a state where one of right and left reference marks (e.g., a vertical line) coincides with the edge of the cylindrical structure and the optical axis is positioned on the surface of the cylindrical structure, and an aperture angle between the optical axis and the reference mark.

Abstract: A survey method comprises a first step for obtaining coordinates of first to fourth points on a wall surface; a second step for specifying first to fourth surfaces; a third step for obtaining distances ?4, ?1, ?2, ?3; a fourth step for determining a largest value ?max among the first to fourth distances ?1 to ?4 as an evaluation value; and a fifth step of defining any of the first to fourth surfaces as a specific surface specifying the wall surface if the evaluation value ?max is less than a predetermined threshold value ?th.

Abstract: Disclosed herein is an optical device that determines the central coordinates of a large-diameter cylindrical structure. The optical device has the function of calculating the central coordinates of a cylindrical structure using the coordinates of a reference point of the optical device, the coordinates of a survey point on the cylindrical structure seen on the optical axis of a telescope in a state where one of right and left reference marks (e.g., a vertical line) coincides with the edge of the cylindrical structure and the optical axis is positioned on the surface of the cylindrical structure, and an aperture angle between the optical axis and the reference mark.