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Sept. 2008 - Now
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Accurate Localization of Eyes and Mouth
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Aimed at precisely localizing the corners of eyes and mouth
under various environment. Recently, Principal Component
Analysis of appearance is used to model the interest areas.
Local Binary Pattern feature and Histogram of Orientated
Gradient feature are accepted in the system now.
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Dec. 2007 - July. 2008
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Research on Camera-based Chinese Document Image Processing
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The most challenge problem in Camera-based document images is the
warped and non- orthogonal paper surface. How to model these
surfaces was the core of thesis. With the hints of visualized 3D
mesh, major and minor texture flows were defined to abstract the
mesh of surface. Finally a carefully designed generative developable
surface model was proposed to depict the document surface which also
gave reasonable constraints so that the warped surface could be
rectified. This is a part of project on Multimedia Information
Retrieval sponsored by National High Technology Research and
Development Program of China.
Here is some results of capturing my master thesis:
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Camera captured image:
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Processed image:
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Sept. 2007 - Jan. 2008
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Research on High-level Feature Extraction from Video
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This is a hot spot research on
Document Analysis and Recognition
now. The most challenging problem is
how to rectify the wrapped document
surface under arbitrary perspective
projection so that it can be easily
analyzed by current plane-based
technology. Analogous to the
visualization of 3D object by meshes,
I adopted major and minor texture flow
of documents to describe the 3D
information of a paper surface, while
the major and minor texture flow
corresponded to the direction of line
text and its orthogonal direction,
respectively. Histogram distribution
analysis of different orientated
projections was applied to estimate
the local major texture flow. A
structural wavelet whitespace detector
(specific to the Chinese characters)
was designed to estimate the local
minor texture flow. I proposed a
global continuity constraint to
suppress the disturbances of noise to
the texture flows estimation. Then I
represent the wrapped paper in reality
in a generative developable surface
model. It is hard to rectify the
developable surface model directly
since the number of estimate
parameters becomes infinite. Inspired
by the differential thought, a group
of ruling lines were estimated to
segment the surface into a batch of
conjoint planes. With the estimated
texture flows of document, ruling
lines were solved in a mathematical
form under the constraint of
continuity of slope. Finally, the
rectification of paper surface can be
simply divided into rectifying a batch
of perspective planes.
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