Image processing device, image processing method and image processing system
The image processing device comprises: a position identification section for identifying positions of two reference points and a position of physical characteristic point of the subject in the moving image; an angle acquisition section for obtaining an angle of a line segment connecting the two reference points with respect to the image plane; a conversion ratio calculation section for calculating a conversion ratio indicating a ratio between the length in the moving image and the length in real space; and a coordinate calculation section for calculating position coordinates of at least one of: the two reference points and the physical characteristic point of the subject in the image plane in the real space, based on the calculated conversion ratio and at least one of: the identified positions of the two reference points and the identified position of the physical characteristic point of the subject.
1 . An image processing device that calculates, from a moving image of a subject performing a swing motion of a club taken by a single image acquisition device, position coordinates in an image plane of the moving image in real space, wherein
the device comprises a processor, and
the processor is configured to:
identify positions of two reference points and a position of physical characteristic point of the subject in the moving image,
obtain an angle of a line segment connecting the two reference points with respect to the image plane,
calculate a conversion ratio indicating a ratio between the length in the moving image and the length in the real space, based on the distance between the two reference points in the moving image, the obtained angle, and the distance between the two reference points in the real space, and
calculate position coordinates of at least one of: the two reference points and the physical characteristic point of the subject in the image plane in the real space, based on the calculated conversion ratio and at least one of: the identified positions of the two reference points and the identified position of the physical characteristic point of the subject.
2 . The image processing device according to claim 1 , wherein
the moving image is a video of the subject taken from the front or a video of the subject taken from the direction of a flying ball line.
3 . The image processing device according to claim 1 , wherein
the two reference points are the positions of a grip end and the center of a head of the club, or the center of both wrists of the subject and the center of the head of the club.
4 . The image processing device according to claim 1 , wherein
the processor obtains the angle from an external input.
5 . The image processing device according to claim 1 , wherein
the processor measures the angle from an image of the subject performing the swing motion taken from a different direction than the moving image.
6 . The image processing device according to claim 1 , wherein
the processor estimates the angle based on the height of the subject or the length of a body part of the subject in the real space.
7 . The image processing device according to claim 1 , wherein
the moving image is a video of a predetermined period of time in the swing motion.
8 . An image processing method using an image processing device that calculates, from a moving image of a subject performing a swing motion of a club taken by a single image acquisition device, position coordinates in an image plane of the moving image in real space, wherein
the method includes:
identifying positions of two reference points and a position of physical characteristic point of the subject in the moving image,
obtaining an angle of a line segment connecting the two reference points with respect to the image plane,
calculating a conversion ratio indicating a ratio between the length in the moving image and the length in the real space, based on the distance between the two reference points in the moving image, the obtained angle, and the distance between the two reference points in the real space, and
calculating position coordinates of at least one of: the two reference points and the physical characteristic point of the subject in the image plane in the real space, based on the calculated conversion ratio and at least one of: the identified positions of the two reference points and the identified position of the physical characteristic point of the subject.
9 . An image processing system comprising a single image acquisition device that takes a subject performing a swing motion of a club, and an image processing device that calculates, from a moving image taken by the single image acquisition device, position coordinates in an image plane of the moving image in real space, wherein
the image processing device comprises:
a processor, and the processor is configured to:
identify positions of two reference points and a position of physical characteristic point of the subject in the moving image,
obtain an angle of a line segment connecting the two reference points with respect to the image plane,
calculate a conversion ratio indicating a ratio between the length in the moving image and the length in the real space, based on the distance between the two reference points in the moving image, the obtained angle, and the distance between the two reference points in the real space, and
calculate position coordinates of at least one of: the two reference points and the physical characteristic point of the subject in the image plane in the real space, based on the calculated conversion ratio and at least one of: the identified positions of the two reference points and the identified position of the physical characteristic point of the subject.