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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Inverse Discrete Cosine Transform by Bit Parallel Implementation and Power Comparision

Bhardwaj, Divya Anshu January 2003 (has links)
<p>The goal of this project was to implement and compare Invere Discrete Cosine Transform using three methods i.e. by bit parallel, digit serial and bit serial. This application describes a one dimensional Discrete Cosine Transform by bit prallel method and has been implemented by 0.35 ìm technology. When implementing a design, there are several considerations like word length etc. were taken into account. The code was implemented using WHDL and some of the calculations were done in MATLAB. The VHDL code was the synthesized using Design Analyzer of Synopsis; power was calculated and the results were compared.</p>
52

Parallel JPEG Processing with a Hardware Accelerated DSP Processor / Parallell JPEG-behandling med en hårdvaruaccelerarad DSP processor

Andersson, Mikael, Karlström, Per January 2004 (has links)
<p>This thesis describes the design of fast JPEG processing accelerators for a DSP processor. </p><p>Certain computation tasks are moved from the DSP processor to hardware accelerators. The accelerators are slave co processing machines and are controlled via a new instruction set. The clock cycle and power consumption is reduced by utilizing the custom built hardware. The hardware can perform the tasks in fewer clock cycles and several tasks can run in parallel. This will reduce the total number of clock cycles needed. </p><p>First a decoder and an encoder were implemented in DSP assembler. The cycle consumption of the parts was measured and from this the hardware/software partitioning was done. Behavioral models of the accelerators were then written in C++ and the assembly code was modified to work with the new hardware. Finally, the accelerators were implemented using Verilog. </p><p>Extension of the accelerator instructions was given following a custom design flow.</p>
53

Implementering av 1D-DCT

Zilic, Edmin January 2006 (has links)
<p>IDCT (Inverse Discrete Cosine Transform) is a common algorithm being used with image and sound decompression. The algorithm is a Fourier related transform which can occur in many different types like, one-dimensional, two-dimensional, three-dimensional and many more.</p><p>The goal with this thesis is to create a fast and low effect version of two-dimensional IDCT algorithm, where techniques as multiple-constant multiplication and subexpression sharing plus bit-serial and bit-parallel arithmetic are used.</p><p>The result is a hardware implementation with power consumption at 19,56 mW.</p>
54

Efficient data encoder for endoscopic imaging applications

Tajallipour, Ramin 05 January 2011
The invention of medical imaging technology revolved the process of diagnosing diseases and opened a new world for better studying inside of the human body. In order to capture images from different human organs, different devices have been developed. Gastro-Endoscopy is an example of a medical imaging device which captures images from human gastrointestinal. With the advancement of technology, the issues regarding such devices started to get rectified. For example, with the invention of swallow-able pill photographer which is called Wireless Capsule Endoscopy (WCE); pain, time, and bleeding risk for patients are radically decreased. The development of such technologies and devices has been increased and the demands for instruments providing better performance are grown along the time. In case ofWCE, the special feature requirements such as a small size (as small as an ordinary pill) and wireless transmission of the captured images dictate restrictions in power consumption and area usage. In this research, the reduction of image encoder hardware cost for endoscopic imaging application has been focused. Several encoding algorithms have been studied and the comparative results are discussed. An efficient data encoder based on Lempel-Ziv-Welch (LZW) algorithm is presented. The encoder is a library-based one where the size of library can be modified by the user, and hence, the output data rate can be controlled according to the bandwidth requirement. The simulation is carried out with several endoscopic images and the results show that a minimum compression ratio of 92.5 % can be achieved with a minimum reconstruction quality of 30 dB. The hardware architecture and implementation result in Field-Programmable Gate Array (FPGA) for the proposed window-based LZW are also presented. A new lossy LZW algorithm is proposed and implemented in FPGA which provides promising results for such an application.
55

Efficient data encoder for endoscopic imaging applications

Tajallipour, Ramin 05 January 2011 (has links)
The invention of medical imaging technology revolved the process of diagnosing diseases and opened a new world for better studying inside of the human body. In order to capture images from different human organs, different devices have been developed. Gastro-Endoscopy is an example of a medical imaging device which captures images from human gastrointestinal. With the advancement of technology, the issues regarding such devices started to get rectified. For example, with the invention of swallow-able pill photographer which is called Wireless Capsule Endoscopy (WCE); pain, time, and bleeding risk for patients are radically decreased. The development of such technologies and devices has been increased and the demands for instruments providing better performance are grown along the time. In case ofWCE, the special feature requirements such as a small size (as small as an ordinary pill) and wireless transmission of the captured images dictate restrictions in power consumption and area usage. In this research, the reduction of image encoder hardware cost for endoscopic imaging application has been focused. Several encoding algorithms have been studied and the comparative results are discussed. An efficient data encoder based on Lempel-Ziv-Welch (LZW) algorithm is presented. The encoder is a library-based one where the size of library can be modified by the user, and hence, the output data rate can be controlled according to the bandwidth requirement. The simulation is carried out with several endoscopic images and the results show that a minimum compression ratio of 92.5 % can be achieved with a minimum reconstruction quality of 30 dB. The hardware architecture and implementation result in Field-Programmable Gate Array (FPGA) for the proposed window-based LZW are also presented. A new lossy LZW algorithm is proposed and implemented in FPGA which provides promising results for such an application.
56

Video Encryption / Video Encryptioning

Yilmaz, Fatih Levent January 2011 (has links)
Video Encryption is nearly the best method for blocking unwanted seizures and viewing of any transmitted video or information. There are several useful techniques that are available for encryping videos. However, one of the unique speciality for human eye is spotting the irregularity in videos due to weak video decoding or weak choice of video encryption hardware. Because of this situation, it is very important to select the right hardware or else our video transmissions may not be secured or our decoded video may be un-watchable. Every technique has advantages and disadvantages over other technical methods.   Line-cut and rotate video encryption method is maybe the best way of acquiring safe, secured and good quality encypted videos. In this method, every line in the video frame cuts and rotates from different points and these cut points are created from a random matrix. The advantage of this method is to supply a coherent video signal, gives an excellent amount of darkness, as well as good decode quality and stableness. On the other hand it’s disadvantages is to have complex timing control and needs specialized encryption equipment.
57

Inverse Discrete Cosine Transform by Bit Parallel Implementation and Power Comparision

Bhardwaj, Divya Anshu January 2003 (has links)
The goal of this project was to implement and compare Invere Discrete Cosine Transform using three methods i.e. by bit parallel, digit serial and bit serial. This application describes a one dimensional Discrete Cosine Transform by bit prallel method and has been implemented by 0.35 ìm technology. When implementing a design, there are several considerations like word length etc. were taken into account. The code was implemented using WHDL and some of the calculations were done in MATLAB. The VHDL code was the synthesized using Design Analyzer of Synopsis; power was calculated and the results were compared.
58

Implementering av 1D-DCT

Zilic, Edmin January 2006 (has links)
IDCT (Inverse Discrete Cosine Transform) is a common algorithm being used with image and sound decompression. The algorithm is a Fourier related transform which can occur in many different types like, one-dimensional, two-dimensional, three-dimensional and many more. The goal with this thesis is to create a fast and low effect version of two-dimensional IDCT algorithm, where techniques as multiple-constant multiplication and subexpression sharing plus bit-serial and bit-parallel arithmetic are used. The result is a hardware implementation with power consumption at 19,56 mW.
59

Protection and Authentication of Digital Image

Lin, Chih-Hung 09 November 2006 (has links)
In this dissertation, the methods of protection and authentication for digital images are presented. In the study of fragile image authentication, the method that can thwart the counterfeit attack is proposed in Chapter 2, and we analyze this method in order to prove the effect. In the study of semi-fragile image authentication, two image authentication methods with digital signature-based and digital watermark-based are presented in Chapter 3 and Chapter 4 respectively. These two methods can improve the disadvantages of related works, and the main contributions are: (1) can adjust the fragile degree by assigning the least authenticable bound of image and (2) the related theorems about the proposed methods are analyzed completely. Finally, a new issue and solution about semi-fragile image authentication are presented in Chapter 5. The main contributions of this method are: (1) only the spatial domain is adopted during feature generation and verification, making domain transformation process is unnecessary, (2) more reasonable non-malicious manipulated images (JPEG, JPEG2000 compressed and scaled images) than related studies can be authenticated, achieving a good trade-off of image authentication between fragile and robust under practical image processing, and (3) non-malicious manipulation is clearly defined to meet closely the requirements of sending them over the Internet or storing images.
60

An Image Encryption Algorithm Robust To Post-encryption Bitrate Conversion

Akdag, Sadik Bahaettin 01 September 2006 (has links) (PDF)
In this study, a new method is proposed to protect JPEG still images through encryption by employing integer-to-integer transforms and frequency domain scrambling in DCT channels. Different from existing methods in the literature, the encrypted image can be further compressed, i.e. transcoded, after the encryption. The method provides selective encryption/security level with the adjustment of its parameters. The encryption method is tested with various images and compared with the methods in the literature in terms of scrambling performance, bandwidth expansion, key size and security. Furthermore this method is applied to the H.263 video sequences for the encryption of I-frames.

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