Efficiency Analysis of the Autofocusing Algorithm Based on Orthogonal Transforms
Open Access JCC
6. Final Remarks
In the paper we presented three implementations of the
image variance estimate evaluation which is the core and
the most computationally demanding part of the autofo-
cusing algorithm. We provided an experimental evidence
that the implementation based on the fast Haar transform
has a much better (by a wide margin) energy efficiency
than the remaining two implementations based on the
discrete cosine and the Walsh-Hadamard transforms.
Somehow unexpectedly, the experiments revealed that
there is no advantage of using the integer number Walsh-
Hadamard transform over the cosine one. Finally, having
in mind an ASIC implementation of the algorithm, we
also proposed the word-selection algorithm which deter-
mines the required precision of the image data with re-
spect to the size of the image data and to the variance of
the noise present in the data. The actual benefit of this
algorithm needs however to be verified experimentally.
Acknowledgements
The work is supported by the NCN gran t UMO-2011/01/
B/ST7/00666.
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