Measurement apparatus, measurement method, and feature identification apparatus

A measuring method comprising:

• by an image displaying unit, performing an image displaying process for displaying an image captured by a camera on a displaying device and prompting a user to specify a position within the image;
• by a measurement image point obtaining unit, performing a measurement image point obtaining process for inputting the position within the image specified by the user as a measurement image point from an inputting device;
• by a vector calculating unit, performing a vector calculating process for calculating a vector showing direction from a center of the camera to the measurement image point inputted by the measurement image point obtaining unit;
• by a neighborhood extracting unit, performing a neighborhood extracting process for extracting one neighboring point of the measurement image point from a three-dimensional point cloud model memory unit and storing a three-dimensional point cloud model including a point cloud each showing a three-dimensional position;
• by a neighboring plane calculating unit, performing a neighboring plane calculating process for calculating a particular plane including the one neighboring point extracted by the neighborhood extracting unit;
• and by a feature position calculating unit, performing a feature position calculating process for calculating an intersecting point of the particular plane calculated by the neighboring plane calculating unit and the vector calculated by the vector calculating unit as a three-dimensional position of the measurement image point, and generating measurement position data showing the three-dimensional position of the measurement image point calculated;
• and projecting the point cloud of the three-dimensional point cloud model on an image-capturing plane of the camera corresponding to the image, wherein the neighborhood extracting unit extracts one of a closest point from the measurement image point in the image-capturing plane among the point cloud of the three-dimensional point cloud model, a closest point from the measurement image point in direction of a horizontal axis of the image-capturing plane, and a closest point from the measurement image point in direction of a vertical axis of the image-capturing plane as the one neighboring point.