US 11,727,637 B2
Method for generating 3D skeleton using joint-based calibration acquired from multi-view camera
Young Ho Seo, Seoul (KR); and Byung Seo Park, Cheongju-si (KR)
Assigned to Kwangwoon University Industry-Academic Collaboration Foundation, Seoul (KR)
Filed by Kwangwoon University Industry-Academic Collaboration Foundation, Seoul (KR)
Filed on Nov. 24, 2021, as Appl. No. 17/535,036.
Claims priority of application No. 10-2020-0174947 (KR), filed on Dec. 15, 2020; and application No. 10-2021-0008979 (KR), filed on Jan. 21, 2021.
Prior Publication US 2022/0189113 A1, Jun. 16, 2022
Int. Cl. G06T 17/20 (2006.01); G06T 7/80 (2017.01); G06T 7/55 (2017.01)
CPC G06T 17/20 (2013.01) [G06T 7/55 (2017.01); G06T 7/80 (2017.01); G06T 2207/30196 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A three-dimensional skeleton generation method using calibration based on a joint acquired from a plurality of cameras, the three-dimensional skeleton generation method comprising:
(a) acquiring a multiview color-depth video of a plurality of viewpoints;
(b) generating a three-dimensional skeleton of each viewpoint from a color-depth video of each viewpoint, and generating a joint of the skeleton of each viewpoint as a feature point;
(c) performing extrinsic calibration for optimizing an extrinsic parameter by using the joint of the skeleton of each viewpoint; and
(d) aligning and integrating the three-dimensional skeleton of each viewpoint by using the extrinsic parameter,
wherein the step (c) includes optimizing a transformation parameter such that an error between an actual coordinate (Xref) of a point cloud of a reference coordinate system and a transformation coordinate (Xi′) by the transformation parameter is minimized, in which the optimization is repeatedly performed by updating a next coordinate transformation parameter Pn+from a current coordinate transformation parameter Pn by the following equation:

OG Complex Work Unit Math
where α is a preset constant, and ∂fError/∂Pn is a partial differentiation of fError with respect to the transformation parameter, and fError is an error function of the coordinate (Xref) and the transformation coordinate (Xi′) by the transformation parameter.