scholarly journals Multiresolution analysis for classification and compression

Author(s):  
April Ellahe Khademi

This thesis contains the application of the DWT [Discrete Wavelet Transform] for classification and compression of biomedical images (mammograms, small bowel and retinal). The shift-invariant DWT and several textural descriptors were used to provide scale, translation and semi-rotational (RST) invariant features. The features were classified using LDA with the leave one out method to combat small database sizes. The small bowel images achieved a classification rate of 75% and is the first reported work in the area, the retinal images achieved 81% classification rate and the mammograms achieved a rate of 59%. The success of the system is a [sic] due to the RST-invariant features which accounted for various sized masses, different camera angles and textural differences between pathologies. Any failures are a result of overlapping tissues which masked the pathologies. JPEG 2000 was the wavelet-based compressor used and it was compared to JPEG-LS, LJPEG, adaptive Huffman, arithmetic and LZW codes. For 12bpp mammgrams, JPEG 2000 offered the best compression (CR of 9.319 and R of 1.288bpp), but suffered from slow compression speeds (501.3 Ksymbols/s). Compression was investigated solely for mammograms since they were the only images stored in raw formats.

2021 ◽  
Author(s):  
April Ellahe Khademi

This thesis contains the application of the DWT [Discrete Wavelet Transform] for classification and compression of biomedical images (mammograms, small bowel and retinal). The shift-invariant DWT and several textural descriptors were used to provide scale, translation and semi-rotational (RST) invariant features. The features were classified using LDA with the leave one out method to combat small database sizes. The small bowel images achieved a classification rate of 75% and is the first reported work in the area, the retinal images achieved 81% classification rate and the mammograms achieved a rate of 59%. The success of the system is a [sic] due to the RST-invariant features which accounted for various sized masses, different camera angles and textural differences between pathologies. Any failures are a result of overlapping tissues which masked the pathologies. JPEG 2000 was the wavelet-based compressor used and it was compared to JPEG-LS, LJPEG, adaptive Huffman, arithmetic and LZW codes. For 12bpp mammgrams, JPEG 2000 offered the best compression (CR of 9.319 and R of 1.288bpp), but suffered from slow compression speeds (501.3 Ksymbols/s). Compression was investigated solely for mammograms since they were the only images stored in raw formats.


Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1023
Author(s):  
Arigela Satya Veerendra ◽  
Akeel A. Shah ◽  
Mohd Rusllim Mohamed ◽  
Chavali Punya Sekhar ◽  
Puiki Leung

The multilevel inverter-based drive system is greatly affected by several faults occurring on switching elements. A faulty switch in the inverter can potentially lead to more losses, extensive downtime and reduced reliability. In this paper, a novel fault identification and reconfiguration process is proposed by using discrete wavelet transform and auxiliary switching cells. Here, the discrete wavelet transform exploits a multiresolution analysis with a feature extraction methodology for fault identification and subsequently for reconfiguration. For increasing the reliability, auxiliary switching cells are integrated to replace faulty cells in a proposed reduced-switch 5-level multilevel inverter topology. The novel reconfiguration scheme compensates open circuit and short circuit faults. The complexity of the proposed system is lower relative to existing methods. This proposed technique effectively identifies and classifies faults using the multiresolution analysis. Furthermore, the measured current and voltage values during fault reconfiguration are close to those under healthy conditions. The performance is verified using the MATLAB/Simulink platform and a hardware model.


2011 ◽  
Vol 60 (5) ◽  
pp. 628-638 ◽  
Author(s):  
Chun-Lung Hsu ◽  
Yu-Sheng Huang ◽  
Ming-Da Chang ◽  
Hung-Yen Huang

2013 ◽  
Vol 464 ◽  
pp. 411-415
Author(s):  
Jin Cai ◽  
Shuo Wang

JPEG 2000 is a new image coding system that uses state-of-the-art compression techniques based on wavelet technology. As interactive multimedia technologies evolve, the requirements for the file format used to store the image data continue to evolve. The size and bit depth collected for an image to increase the resolution and extend the dynamic range and color gamut. Discrete Wavelet transform based embedded image coding method is the basis of JPEG2000. Image compression algorithm for the proper use and display of the image is a requirement for digital photography.


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