Optical tracking system, and method for calculating posture and location of marker part in optical tracking system

Patent metadata

Field	Value
Publication number	US-10109066-B2
Application number	US-201515314672-A
Country	US
Kind code	B2
Filing date	May 29, 2015
Priority date	May 29, 2014
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

An optical tracking system includes a marker part, an image forming part, and a processing part. The marker part includes a pattern having particular information and a first lens. First and second image forming parts include second and third lenses and first and second image forming units. The processing part determines the posture of the marker part from a first coordinate conversion formula between a coordinate on the pattern surface of a pattern and first pixel coordinate on a first image of the pattern, and a second coordinate conversion formula between a coordinate on the pattern surface of the pattern and second pixel coordinate on a second image of the pattern, the second coordinate conversion formula including the rotation conversion between the first pixel coordinate and the second pixel coordinate and tracks the marker part by using the posture of the marker part.

First claim

What is claimed is:

1. An optical tracking system comprising:
a marker configured to include a pattern that has particular information and a first lens that is spaced apart from the pattern and has a first focal length;
a first image lens and sensor combination configured to include a second lens that has a second focal length and a first imaging sensor that is spaced apart from the second lens and on which a first image of the pattern is formed by the first lens and the second lens;
a second image lens and sensor combination configured to include a third lens that has a third focal length and a second image imaging sensor that is spaced apart from the third lens and on which a second image of the pattern is formed by the first lens and the third lens; and
a processor configured to determine a posture of the marker from a first coordinate conversion formula between a coordinate on a pattern surface of the pattern and a first pixel coordinate on the first image of the pattern and from a second coordinate conversion formula between the coordinate on the pattern surface of the pattern and a second pixel coordinate on the second image of the pattern, the second coordinate conversion formula including a rotation conversion between the first pixel coordinate and the second pixel coordinate, and configured to track the marker.

2. The optical tracking system according to claim 1 , wherein the processor acquires:
the first conversion matrix that converts a first coordinate corresponding to a coordinate on the pattern surface of the pattern to a second coordinate corresponding to a three-dimensional coordinate for the first lens of the marker;
the second conversion matrix that converts a third coordinate corresponding to a three-dimensional coordinate of the second coordinate for the second lens to a fourth coordinate corresponding to the first pixel coordinate on the first image of the pattern of the first image lens and sensor combination;
the third conversion matrix that is the same as the first conversion matrix and converts a fifth coordinate corresponding to a coordinate on the pattern surface of the pattern to a sixth coordinate corresponding to a three-dimensional coordinate for the first lens of the marker; and
the fourth conversion matrix that converts a seventh coordinate corresponding to a three-dimensional coordinate of the sixth coordinate for the third lens to an eighth coordinate corresponding to the second pixel coordinate on the second image of the pattern of the second image lens and sensor combination,
wherein the first coordinate conversion formula is defined to convert the first coordinate to the fourth coordinate while including the first conversion matrix and the second conversion matrix, and the second coordinate conversion formula is defined to convert the fifth coordinate to the eighth coordinate while including the third conversion matrix and the fourth conversion matrix, and
wherein the processor acquires, from the first coordinate conversion formula and the second coordinate conversion formula, a first posture definition matrix that defines the posture of the marker with respect to the first image lens and sensor combination.

3. The optical tracking system according to claim 2 , wherein the first coordinate conversion formula is defined by

s
⁡

[

lu
′

lv
′

1

]

=

[

A
l

]

⁡

[

R
L

]

⁡

[
C
]

⁡

[

lu

lv

1

]

,

wherein {(lu,lv) denotes the first coordinate, (lu′,lv′) denotes the fourth coordinate, [C] denotes the first conversion matrix, [A l ] denotes the second conversion matrix, [R L ] denotes the first posture definition matrix, and s denotes a proportional constant}, and
the second coordinate conversion formula is defined by

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[

ru
′

rv
′

1

]

=

[

A
r

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[

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R

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Assignees

• Koh Young Tech Inc
• Kyungpook Nat Univ Ind Academic Coop Found

Inventors

• Lee Hyun Ki
• Chae You Seong
• Kim Min Young

Classifications

• G06T7/20 Primary

  Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) · CPC title

• G06T2207/30204

  Marker · CPC title

• G06T2207/10056

  Microscopic image · CPC title

• G06T7/73

  using feature-based methods · CPC title

• G06T7/80

  Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration · CPC title