HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
Semi-automatic and easy creation of learning friendly OCW video content
1. OCWC Global meeting 2011
Semi-automatic and easy creation of
learning friendly OCW video content
C
Satoshi SHIMADA1, TadashiNAKANISHI1, Akira KOJIMA1
and Y hi i FUKUHARA
d Yoshimi 2
1NTT Cyber Solutions Laboratories 2Meiji University
y j y
2. Motivation
Creating a learning-friendly edited video, for video sharing
g g y , g
on the web, is painful and time-consuming.
Take time
Good skills required
Costs money
How to make this process easy?
At the same time how to make edited video learning
time,
friendly ?
The goal is to automatically extract information from a
lecture video and use them to produce a better version of
the video.
3. Problem
We need to take a video and edit it.
The cost of video capture can be reduced by fix HD camera.
Wide angle HD camera can record whole of lecture.
However, HD video is not suitable for sharing on the Web.
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Because,
(1)File size of HD video is too large
(2)Slide in simple downsizing video
is
i unreadable
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(3)The entire scene is boring
( ) Video captured by
fixed camera
Video editing manually takes much time
time.
4. Proposed method
Proposed method
Proposed workflow for the easy and better creation
Cature the entire scene to a video bird's-eye view
by Full HD camera
Video file is moved to Laptop
Automatic detection of important
Information Semi-automatic
S
Screen/Speaker/Slide change
/Sp a /S a g transformation
Post-production
Post production (Mixing)
Screen + Speaker +
Slide change information
produced video
5. Principle
1920 pixels
i l
- speaker
- Screen or black board
- atmosphere of hall
are assembled based on 1080 pixels
editing template
-projection di t ti of screen
j ti distortion f
-brightness of speaker
brightness Editing template A Editing template B
Editi t l t
are corrected
corrected.
720 pixels
400 pixels
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6. Video processing
Video processing
(1)Speaker detection find faces in the image
detection:
linear Interpolation is conducted for no face image
(2) SScreen d t ti
detection: fi d a rectangle under appropriate
find t l d i t
conditions, size and vertex angle
diti i d t l
Because th camera can b positioned almost everywhere
B the be iti d l t h
in the lecture room a homography is used to map the
room,
screen coordinates to a flat rectangle as if it was seen
from the front of it
it.
(3) Chaptering: Based on a subtraction method upon N
equidistant frames to determine if a ‘Slide change’ has
occurred or not in ‘Screen region’
S
7. Usability evaluation
15 Participants without prior knowledge were asked how
they reviewed the p
y post-processed video in comparison
p pa
with the original one.
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Videos used: 4(=20min×2, 1hour×2) ,720×408 pixels
Comparison of M
C i f Mean O i i S
Opinion Score
Original video Proposed method
Original video
(simple down conversion) S
Screen visibility
y
Speaker visibility
Not boring
g
Presence
Overall impression
Post
P t processed video
d id for learning use 1 2 3 4 5
by the proposed method bad good
8. Other example
Other example
Original id
O i i l video
Facial search area Screen area set
by manually
Post processed video by the proposed method
at the b i of l
h begin f lecture at the middle of l
h iddl f lecture
9. Video sharing on the Web
Video sharing on the Web
Enhance the video sharing function by using
SceneKnowledge, which provides a user-friendly web
interface to view videos, annotate them and post comment.
Post-produced
P t d d
lecture video
Annotation
Chapter is displayed within a
certain
chapter of the
Comment input form video
SceneKnowledge: A Video scene-based video sharing and
comment posting system
10. How to use our software
How to use our software
SceneEditor is a client software implementing the proposed
method.
Minimum operation is as follows
1.
1 determine the editing duration
2. Set facial search area
3. Set clipping area of speaker
4. detect screen a a
. area
5. select or set an editing template
g p
6. comand video procressing
--- auto processing ---
Time required for automated post-production is;
post production
Roughly correspond to the time of the video itself