Type of Document Master's Thesis Author Faridi, Imran Zafar Author's Email Address ifaridi1@student.gsu.edu URN etd-04282005-144927 Title Image Compression Using Bidirectional DCT to remove Blocking Artifacts Degree Master of Science Department Computer Science Advisory Committee
Advisor Name Title Dr. Saeid Belkasim Committee Chair Dr. Raj Sunderraman Committee Member Dr. Yi Pan Committee Member Keywords
- Bidirectional Discrete Cosine Transform
- blocking artifacts
Date of Defense 2005-04-22 Availability restricted Abstract Discrete Cosine Transform (DCT) is widely used transform in many areas of the currentinformation age. It is used in signal compression such as voice recognition, shape recognition and
also in FBI finger prints. DCT is the standard compression system used in JPEG format. The
DCT quality deteriorates at low-bit compression rate. The deterioration is due to the blocking
artifact inherent in block DCT. One of the successful attempts to reduce these blocking artifacts
was conversion of Block-DCT into Line-DCT. In this thesis we will explore the Line-DCT and
introduce a new form of line-DCT called Bidirectional-DCT, which retains the properties of Line-
DCT while improving computational efficiency. The results obtained in this thesis show
significant reduction in processing time both in one dimensional and two dimensional DCT in
comparison with the traditional Block-DCT. The quality analysis also shows that the least mean
square error is considerably lower than the traditional Block-DCT which is a consequence of
removing the blocking artifacts. Finally, unlike the traditional block DCT, the Bidirectional-DCT
enables compression with very low bit rates and very low blocking artifacts.
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