WE CLAIM:
1. A data thinning device comprising:
a coordinate calculation unit for, on a basis of data which is related to a plurality of distance measurement points and which indicates distances to and angles of the respective distance measurement points measured by a distance measuring device mounted in a moving body using a laser beam and indicates coordinates of an irradiation reference point of the laser beam measured by a coordinate measuring device mounted in the moving body, and on a basis of an attitude angle of the moving body, calculating coordinates of each of the distance measurement points on a corresponding image among a plurality of images obtained in such a way that an area including the distance measurement points is periodically shot by a shooting device mounted in the moving body;
a feature point extraction unit for extracting feature points for each of the images;
a distance calculation unit for calculating, for each of the distance measurement points, in the corresponding image, a distance to a nearby feature point among the feature points extracted by the feature point extraction unit, on a basis of the coordinates calculated by the coordinate calculation unit; and
a necessity determination unit for deleting unnecessary data from the data related to the distance measurement points on a basis of a calculation result by the distance calculation unit.
2. The data thinning device according to claim 1, further comprising
an edge determination unit for determining, for each of the distance
measurement points, in the corresponding image, whether the coordinates calculated by

the coordinate calculation unit indicate a point at which an edge portion of an object is observed,
wherein the necessity determination unit deletes unnecessary data from the data related to the distance measurement points on a basis of a determination result by the edge determination unit.
3. The data thinning device according to claim 1 or 2, further comprising
a vegetation determination unit for determining, for each of the distance
measurement points, in the corresponding image, whether the coordinates calculated by the coordinate calculation unit indicate a point at which vegetation is observed,
wherein the necessity determination unit deletes unnecessary data from the data related to the distance measurement points on a basis of a determination result by the vegetation determination unit.
4. A surveying device comprising:
a coordinate calculation unit for, on a basis of data which is related to a plurality of distance measurement points and which indicates distances to and angles of the respective distance measurement points measured by a distance measuring device mounted in a moving body using a laser beam and indicates coordinates of an irradiation reference point of the laser beam measured by a coordinate measuring device mounted in the moving body, and on a basis of an attitude angle of the moving body, calculating coordinates of each of the distance measurement points on a corresponding image among a plurality of images obtained in such a way that an area including the distance measurement points is periodically shot by a shooting device mounted in the moving body;
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a feature point extraction unit for extracting feature points for each of the images;
a distance calculation unit for calculating, for each of the distance measurement points, in the corresponding image, a distance to a nearby feature point among the feature points extracted by the feature point extraction unit, on a basis of the coordinates calculated by the coordinate calculation unit;
a necessity determination unit for deleting unnecessary data from the data related to the distance measurement points on a basis of a calculation result by the distance calculation unit; and
a navigation device for setting an attitude angle of the moving body using the data related to the distance measurement points from which the unnecessary data is deleted by the necessity determination unit.
5. A surveying system comprising:
a distance measuring device mounted in a moving body, for measuring distances to and angles of a respective plurality of distance measurement points using a laser beam;
a coordinate measuring device mounted in the moving body, for measuring coordinates of an irradiation reference point of the laser beam;
a shooting device mounted in the moving body, for obtaining images by periodically shooting an area including the distance measurement points;
a coordinate calculation unit for, on a basis of data which is related to the distance measurement points and which indicates distances to and angles of the respective distance measurement points measured by the distance measuring device and indicates the coordinates measured by the coordinate measuring device, and on a basis
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of an attitude angle of the moving body, calculating coordinates of each of the distance measurement points on a corresponding image among the images obtained by the shooting device;
a feature point extraction unit for extracting feature points for each of the images,
a distance calculation unit for calculating, for each of the distance measurement points, in the corresponding image, a distance to a nearby feature point among the feature points extracted by the feature point extraction unit, on a basis of the coordinates calculated by the coordinate calculation unit;
a necessity determination unit for deleting unnecessary data from the data related to the distance measurement points on a basis of a calculation result by the distance calculation unit; and
a navigation device for setting an attitude angle of the moving body using the data related to the distance measurement points from which the unnecessary data is deleted by the necessity determination unit.
6. A data thinning method comprising:
a step of, by a coordinate calculation unit, on a basis of data which is related to a plurality of distance measurement points and which indicates distances to and angles of the respective distance measurement points measured by a distance measuring device mounted in a moving body using a laser beam and indicates coordinates of an irradiation reference point of the laser beam measured by a coordinate measuring device mounted in the moving body, and on a basis of an attitude angle of the moving body, calculating coordinates of each of the distance measurement points on a corresponding image among a plurality of images obtained in such a way that an area including the
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distance measurement points is periodically shot by a shooting device mounted in the moving body;
a step of, by a feature point extraction unit, extracting feature points for each of the images;
a step of, by a distance calculation unit, calculating, for each of the distance measurement points, in the corresponding image, a distance to a nearby feature point among the feature points extracted by the feature point extraction unit, on a basis of the coordinates calculated by the coordinate calculation unit; and
a step of, by a necessity determination unit, deleting unnecessary data from the data related to the distance measurement points on a basis of a calculation result by the distance calculation unit.
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