29 October 2008

plantationscarfAI and Robotics

Nov 25, 2013 (3 years and 8 months ago)

92 views


Presented by
Sungkuk

Chun

29 October 2008

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1. Purpose


Constructing 3D Star Skeleton for


Human posture recognition


Simple and real time technique


Consideration of 3D information



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2. Related works for
Skeletonization

SKELETONIZATION

Accurate Skeleton

-
Distance Transformation

-
Voronoi

Diagram

-
Thinning

Posture Recognition

-
Star Skeleton

-
Greedy 3D Star Skeleton


<Distance Transform>

<Thinning>

<Star Skeleton>

Execution Time

Limitation for human
posture representation

Execution Time

3D Star Skeleton

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3. System Flow

Finding 5 Candidates

at each projection map

Transforming all candidates
into one coordinate system

Clustering and
Constructing

3D star skeleton

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4. Projection map

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4. Projection map


contains 3D information of human posture


We use the 8 projection maps.


To apply the 3D data to proposed star skeleton


-
> ensure the more accurate 3D skeleton than the existing star
skeleton.

pixel value : distance from a camera

X

Y

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5. Finding Candidates

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5. Finding Candidates
-

1


Candidates


likely to be the final extremities of star skeleton


5 candidates in each projection map


located where distance is maximal from the
centroid


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5. Finding Candidates
-

2

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6. Transformation

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6. Transformation


Move the all candidates of each projection map to one
particular coordinate


Reflection


Translation


Axis shift operation


Rotation





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7. Clustering and

Constructing final 3D star skeleton

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Cluster the candidates scattered in 3D space


Modified K
-
Means Clustering algorithm
(K = 5)


Filtering clusters


Removing the noise causing to means error


Obtain the
centroid

: take an average on all
centroids

of all
projection maps


Connect the means of clusters with the
centroid

7. Clustering and

Constructing final 3D star skeleton

Noise

Mean

Mean

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8. Experimental Result


The number of Operation time



The generation result of skeleton



Correlation btw the Rotation of human and the number of
projection map

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8. Experimental Result
-
1


The number of Operation time


Superior to Greedy Star skeleton


Inferior to the existing 2D star skeleton

2D S
TAR

S
KELETON

3D Star Skeleton

The number of boundary
points

1880

9880

Processing time(ms)

81

734

-
>
70~80

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8. Experimental Result
-
2


3D Star Skeleton


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8. Experimental Result
-
3


Correlation btw the Rotation of human and the number of
projection map


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8. Conclusion


The Proposed 3D Star skeleton


represents
human posture for recognition.


reflects 3D information of human posture.


For the future work, we have to


define the reasonable number of extremities(K).


prove the advantage more clearly.


study human action recognition based on the our system.






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