Information Technology Reference
In-Depth Information
Thus, the encoding time depends on the image size and on the total number of
code-words in
all bitplanes
. It is now obvious why it is so important to reduce the
codebook size, as previously discussed.
For instance, assuming a 512 × 512 image and a typical
with
m =
6 most
D
8
6
10
significant bitplanes, the result is
. For a clock frequency of
T
#
CLK
T
13
encode
9
20 MHz (
T
CLK
50
10
s
, typical for any cheap micro-controller) it follows that
0#
, which may be reasonable enough for still images. Using high-speed
customary designed circuitry may increase the speed up to 100 times, sufficient
enough to accommodate moving pictures. Moreover, by using FPGAs, the CA-VQ
algorithm may be easily ported to a parallel implementation (several processors
operating independently on sub-domains of the input images) to obtain a similar
gain in speed while taking benefits of the reasonable costs for implementation and
development using the FPGA technology.
T
encode
.
65
s
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