Method and apparatus for extracting features of moving objects
AssigneeNippon Telephone and Telegraph Corporation
InventorKoichi Kato
Life of this patent
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Abstract
The present invention is intended to reconstruct or acquire the shape of an object without rotating it. A TV camera with a fish-eye lens is used to conduct the image-sensing of a vehicle as a moving object over a certain section of its path of travel and a background image is subtracted from each captured image to obtain a silhouette of the vehicle. The loci of movement of the vehicle's tires in each image are calculated and used to calculate the positions of the viewpoint of the TV camera and the vehicle relative to each other in each image. The shape of the vehicle is reconstructed by projecting the silhouette for each captured image into a projection space while holding the viewpoint of the TV camera and the vehicle at the calculated relative positions.
Claims14
A method for acquiring a feature of a moving object, said method comprising:
- an image capturing step using a fixed TV camera for performing image-sensing of said moving object at least two times along a predetermined section of the path of travel of said moving object from a position on a line crossing the path of travel of said moving object;
- a silhouette extraction step for calculating the difference between each image of said moving object captured by said TV camera and its background image to generate a silhouette for said each image of said moving object;
- a relative position calculation step for calculating the relative positions of the viewpoint of said TV camera and said moving object on the basis of information about a surface feature point of said moving object in said each image;
- and
- a shape extraction step for extracting the shape of said moving object as a reconstructed shape by projecting said silhouette of said each image into a three-dimensional projection space assumed to be large enough to accommodate an assumed version of the shape of said moving object on the assumption that said viewpoint of said TV camera and said moving object are held at said relative positions.
A method for acquiring a feature of a moving object, said method comprising:
- an image capturing step using a TV camera for performing image-sensing of said moving object at least two times along a predetermined section of the path of travel of said moving object while turning the line of view of said TV camera to keep track of said moving object in its field of view at all times;
- a silhouette extraction step for calculating the difference between each image of said moving object captured by said TV camera and its background image to generate a silhouette for said each image of said moving object;
- a relative position calculation step for calculating the relative position of the center of turning of said line of view of said TV camera and said moving object on the basis of information of a surface feature point of said moving object in said each image;
- and
- a shape extraction step for acquiring the shape of said moving object by projecting said silhouette of said each image into a three-dimensional projection space assumed to be large enough to accommodate an assumed version of the shape of said moving object on the assumption that the center of turning of said line of view of said TV camera and said moving object are held at said relative positions.
An apparatus for acquiring a feature of a moving object, said apparatus comprising:
- a stationary TV camera disposed apart from a path of travel of said moving object, for performing image-sensing of said moving object at least two times in a predetermined section of said path of travel, said TV camera having a wide-angle objective lens;
- and
- an image processor which generates a silhouette of said moving object by subtracting a background image from each image captured by said TV camera, calculates the relative positions of the viewpoint of said TV camera and said moving object on the basis of information about a surface feature point of said moving object in each image captured by said TV camera, and reconstructs the shape of said moving object by projecting said silhouette of said moving object into a three-dimensional projection space while holding said viewpoint of said TV camera and said moving object at said relative positions.
An apparatus for acquiring a feature of a moving object, said apparatus comprising:
- a TV camera disposed apart from a path of travel of said moving object, for image-sensing said moving object at least two times in a predetermined section of said path of travel;
- means for turning said TV camera so that said moving object having entered said predetermined section stays in the field of view of said TV camera;
- and
- an image processor which generates a silhouette of said moving object by subtracting a background image from each image captured by said TV camera, calculates the relative positions of the turning center of said TV camera and said moving object on the basis of information about a surface feature point of said moving object in each image captured by said TV camera, and reconstructs the shape of said moving object by projecting said silhouette of said moving object into a three-dimensional projection space while holding said turning center of said TV camera and said moving object at said relative positions.
Dependencies are inferred from the claim text.