Image Processing Reference
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iments, we use the 320 × 240 pixels half-size frames. In the MPEG format, each 16 × 16 pixels
block holds a motion compensation vector. This leads to reduce the amount of information in-
to 1/256. The resulting motion image is 20 × 15 pixels. The 1D degenerated description is 7/60
of the original 20 × 15 pixels image. As a result, the usage of the ST image of motion compens-
ation vector in MPEG video reduces the amount of information into 0.045% from the original
half-size video frames. In the ST image used in this paper, X -axis holds the space and Y -axis
does the time. There is no reduction in information in time axis.
The similar motion retrieval estimates what kind of motions exists on a place. It is same as
the cost of the retrieval on images to retrieve similar part of videos on an ST image.
There are many similar image retrieval methods. They can be applied in ST images describ-
ing videos' motions. This paper uses the correlation between two images. We normalize the
resulting correlations for compensating the variance among videos. We have two independent
correlations between two ST images from each color plane. The blue plane exists for only the
convenience for our eyes. We use an X -direction motion and a Y -direction motion in red and
green planes.
3.4 Matching Between Template ST Image and Retrieved ST
All ST images have same space direction size. The estimated motion image is X × Y pixels.
Then, the size of the space axis of ST images is X + Y pixels. For computing the correlations
between the template ST image and any part of retrieved ST image, there is no freedom on
space axis. There is only the freedom on time axis. If a template ST image is S × t and a re-
trieved ST image is S × T , the computation cost of correlations is S × t × T .
T.In a baseball game, the length t of an interesting play of a video is short. Therefore, the com-
putational cost of correlations is small enough to be able to apply large-scale video retrieval.
Because of the shortness of the retrieved part, there is no need to compensate the length of the
part. There is no very slow pitch or no very fast one. There is no very slow running or no very
fast one.
4 Similarity Measure with Correlation and Absolute
Difference in Motion Retrieving Method
4.1 Similarity Measure in Motion Space-Time Image
Based on Correlations
We use the mutual correlation as the measure of similarity. We have two-dimensional cor-
relation vectors. They are X -direction motion, Y -direction motion. If there is a similar motion
between the template and the retrieved part of ST image, both of the two correlations are large.
We use the similarity measure shown as follows:
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