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Discrete Cosine Transform and its Application in Forensic Investigations
Name
Institution
CJUS542 Tools and Image Recovery
Professor’s Name
Date of Delivery
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Discrete Cosine Transform and its Application in Forensic Investigations
A discrete cosine transform (or DCT) deals with finite data points in terms of an
aggregate of cosine functions which oscillate at various frequencies. This technology was first
introduced in 1972 by an Indian-American electrical engineer called Nasir Ahmed. Its use in data
compression and signal processing has become prevalent; and a significant number of digital
media utilize it in one way or the other. In HEIF and JPEG, for instance, DCT facilitates the
discarding of a small amount of high-frequency components in a bid to arrive at the desired
results (Lopez, 2019).
The technique is also used in the production of digital audio like AAC, Dolby Digital,
and MP3; speech coding; digital television; and digital radio. In essence, therefore, DCT has
become almost indispensable as far as developing and using engineering and science applications
is concerned. Among the reasons behind its use include the need to reduce network bandwidth
usage, as spectral approaches for numerical solution, digital signal processing, as well as in
telecommunication devices (Nelson, Phillips, & Steuart, 2019).
In all these cases, the use of cosine is strategic, and this is due to how effectively it
facilitates compression. It is imperative to recognize the fact that just a handful cosine functions
are necessary to facilitate the approximation of typical signals. DCT (or block) compression is
comprised of pieces of data in the sets of discrete blocks. The blocks may be of various sizes,
and these include the 4x4, 8x8, and 32x32 pixels. The technology is also noted for having strong
energy-compression rates (Nelson et al., 2019).
Although there are several other places where the DCT technology is applied, this
discussion pertains to its use in image compression. First, it is worth noting that such tools and
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software as Paintshop Pro, digital cameras, and Photoshop digital may produce counterfeit
images with relative ease. This is due to how easily their edit functions work.
According to Griffin, Tatar, & Yankson (2022), various techniques which would
facilitate the detection of tempered images have been proposed in literature. This information is
important to a digital forensic professional, and that is because there could be several instances
when they are expected to determine if a particular image has been forged or not. They may also
be required to uncover when that forgery happened, and what exactly was done on those images.
An understanding of DCT can help in that process as it facilitates the uncovering of the
specific areas where parts of the image have been copied and moved. This basically means that
once can tell how the image of interest has been manipulated (Nelson et al., 2019). In the world
of computing (and, certainly, digital image manipulation), solutions have a high rate of
obsolescence. As a consequence, therefore, a professional is expected to keep on refreshing their
skills I order to tackle the emergent threats and challenges in an effective manner (Lopez, 2019).
In Proverbs 22:29, the Bible teaches that those who are skilled in their craftsmanship will
overcome challenges and gain favor in the eyes of the important individuals in their society
(King James Bible, 2022). An IT professional, and especially one dealing with digital forensics,
is supposed to keep on learning because this is an ever-changing field. If they so that, they will
be able to deal with the kind of adversities which derail the ignorant individuals.
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References
Griffin, R. P., Tatar, U., & Yankson, B. (2022). ICCWS 2022 17th international conference on
cyber warfare and security. Academic Conferences and Publishing Limited.
King James Bible. (2022). King James Bible online. https://www.kingjamesbibleonline.org/
(Original work published 1769).
Lopez, A. (2019). Digital forensics tools and techniques. GRIN Verlag.
Nelson, B., Phillips, A., & Steuart, C. (2019). Guide to Computer Forensics and Investigation.
Cengage.
