Download Video Content Analysis Tool: 3DVideoAnnotator

Fig
gure 54: Th
he keyframe selector GUI
G
At the timee of this wriiting, three algorithm iimplementaations are av
vailable, thaat can be seelected from
m
the parametter input meenu. All thrree of them at their corre need to co
ompute disttances betw
ween framess.
For the fi
first two algorithms,
a
the distannce betweeen two frrames is tthe sum of
o all theirr
corresponding(having same coord
dinates) piixel distancces. Pixel distances cann be compu
uted by twoo
methods in this libraryy:
a. Disttance of th
he averagess of pixels: initially an
n average value
v
based on the RG
GB values of
the pixel is com
mputed (in essence thee pixel is sim
mply transfformed to grreyscale). The
T distancee
of tw
wo pixels iss the distancce of their aaverage valu
ues.
b. Eucclidean disstance of pixels:
p
the distance of
o two pixeels is compputed as an
n Euclideann
distance, (the square
s
root of the sum
m of the RGB values sq
quared). Thhis type of distance
d
is a
bit m
more precisse but sloweer than the ffirst one.
i
param
meter menu aare the follo
owing:
The algorithhms in the input
a. Sim
mple Distan
nces of Fra
ames: This algorithm initially
i
com
mputes the distance fo
or each shoot
fram
me pair (thaat is for fraame pairs 11-2, 1-3, … , 2-3, …) where the distance between
b
twoo
fram
mes is definned as the su
um of their ccorrespondiing(having same coorddinates) pixeel distancess,
as m
mentioned above.
a
After all distancces among shot framess are compuuted, the keeyframe cann
be dderived as the
t one thatt has the sm
mallest sum
m of frame distances,
d
m
meaning thaat is the onee
clossest to mostt other shot frames.
b. Disttances from
m Average Frame: Thhis algorith
hm computees an “averaage” shot frrame, whichh
in eessence is a frame whose
w
pixeels hold th
he averagee value of all the sh
hot frames’
corrresponding pixels. Thee keyframe will then be the one th
hat has the least distan
nce from thee
averrage frame.. Frame disstances are also compu
uted based on pixel diistances herre, as in thee
firstt algorithm. This is by far the fasteest algorithm
m of the two
o but slightlly less accu
urate.
c. Disttances of frame Histograms
H
s: This algorithm
a
follows a similar process too
KFS
SelectorAllD
Distances to produce its keyfram
mes, with th
he only diffference beiing that thee
distance betweeen two fram
mes in thiss algorithm is not the sum of theeir correspo
onding pixeel
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