IEEE Consumer Electronics Magazine - July 2018 - 21

Table 1. The relationship between bones and their weights.
Number

Bone

Weight

Number

Bone

Weight

Head-shoulder center

0.01

Wrist left-hand left

0.01

Shoulder center-spine

0.003

Hip center-hip right

0.003

Spine-hip center

0.006

Hip right-knee right

0.04

Shoulder center-shoulder right

0.06

Knee right-ankle right

0.1

Shoulder right-elbow right

0.085

Ankle right-foot right

0.01

Elbow right-wrist right

0.15

Hip center-hip left

0.003

Wrist right-hand right

0.01

Hip left-knee left

0.04

Shoulder center-shoulder left

0.006

Knee left-ankle left

0.1

Shoulder left-elbow left

0.09

Ankle left-foot left

0.01

Elbow left-wrist left

0.17

difference between the user and choreographer model can be
calculated by combining the weights and difference of bone
eigenvectors. The implementation of the evaluation algorithm
is shown in Figure 7.

DESIGN OF THE PAC SYSTEM

back mode. Each movement of the player can be recognized
and scored according to the comparison to the corresponding
standard movements in the database. More importantly, the substandard four important parts can be demonstrated to help the
user adjust immediately. Therefore, students receive the essentials of each movement and the whole continuity of the dance
after feedback mode.

PRACTICE MODE
The hand-waving dance is not easy for a beginner to grasp.
However, it will be easier for a user to master a new dance
when he or she is taught breakdowns of the dance by a coach.
Practice mode is the first scene of the PAC, and users can
dance by following the virtual choreographer just like imitating a real choreographer who is beside them. This mode can
help new students learn more about the basic moves of the
hand-waving dance because such movements are determined
by the professional choreographer. In addition, each basic
movement contains several frames of the static move, and the
movements database contains almost all of the basic movements of the hand-waving dance for evaluation of the user's
movement. Moreover, students can eventually imitate the
moves of the virtual choreographer in practice mode. The
player can advance to the next movement only if his or her
score of the movement reaches 14, i.e., the player cannot
move on until the present movement is qualified.

FEEDBACK MODE
Feedback is a key function of the choreographer. An instant
feedback from the choreographer can facilitate the learning
effect, which has been confirmed by many researchers. Students can master the basic movements of the hand-waving
dance after practice mode, but the continuity of the whole dance
still needs improvement. Hence, feedback mode is designed and
developed. Users can learn the whole continuity of the handwaving dance by following the virtual choreographer in feed-

DOUBLE MODE
Constructivist learning theory and game-based learning show
that companionship and joy are two key factors that influence
learning efficiency. The double mode is a fusion of a learning
partner, competitiveness, and enjoyment. Kinect can be used to
track two dancers at the same time, so two users can learn the handwaving dance together following the same virtual choreographer.

Get 3-D Coordinates of Each Joint
Calculate Bone
Vector of Adjacent
Joints

Calculate Cosine
Eigenvalue of Each
Bone Vector

Get a 19 × 3 Eigenmatrix
of the 19 Bones from the Body
Compare the Difference Between
the Movement of User and Instructor
Get the Final Score and Visualized
Presentation Combined with Weight

FIGURE 7. The implementation of the evaluation algorithm.

july 2018

IEEE Consumer Electronics Magazine

Table of Contents for the Digital Edition of IEEE Consumer Electronics Magazine - July 2018