• Title/Summary/Keyword: two-bit transform

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Hardware Accelerated Design on Bag of Words Classification Algorithm

  • Lee, Chang-yong;Lee, Ji-yong;Lee, Yong-hwan
    • Journal of Platform Technology
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    • v.6 no.4
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    • pp.26-33
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    • 2018
  • In this paper, we propose an image retrieval algorithm for real-time processing and design it as hardware. The proposed method is based on the classification of BoWs(Bag of Words) algorithm and proposes an image search algorithm using bit stream. K-fold cross validation is used for the verification of the algorithm. Data is classified into seven classes, each class has seven images and a total of 49 images are tested. The test has two kinds of accuracy measurement and speed measurement. The accuracy of the image classification was 86.2% for the BoWs algorithm and 83.7% the proposed hardware-accelerated software implementation algorithm, and the BoWs algorithm was 2.5% higher. The image retrieval processing speed of BoWs is 7.89s and our algorithm is 1.55s. Our algorithm is 5.09 times faster than BoWs algorithm. The algorithm is largely divided into software and hardware parts. In the software structure, C-language is used. The Scale Invariant Feature Transform algorithm is used to extract feature points that are invariant to size and rotation from the image. Bit streams are generated from the extracted feature point. In the hardware architecture, the proposed image retrieval algorithm is written in Verilog HDL and designed and verified by FPGA and Design Compiler. The generated bit streams are stored, the clustering step is performed, and a searcher image databases or an input image databases are generated and matched. Using the proposed algorithm, we can improve convenience and satisfaction of the user in terms of speed if we search using database matching method which represents each object.

Iterative Image Restoration Algorithm Using Power Spectral Density (전력밀도 스펙트럼을 이용한 반복적 영상 신호 복원 알고리즘)

  • 임영석;이문호
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.4
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    • pp.713-718
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    • 1987
  • In this paper, an iterative restoration algorithm from power spectral density with 1 bit sign information of real part of two dimensional Fourier transform of image corrupted by additive white Gaussian noise is proposed. This method is a modified version of image reconstruction algorithm from power spectral density. From the results of computer simulation with original 32 gray level imgae of 64x64 pixels, we can find that restorated image after each iteration converge to original image very fast, and SNR gain be at least 8[dB] after 10th iteration for corrupted image with additive white Gaussian noise.

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Enhanced Spectral Envelope Coding Scheme Using Inter-frame Correlation for G.729.1 (G.729.1 코더에서 프레임 간의 상호상관 관계를 이용한 개선된 스펙트럼 포락 코딩 방법)

  • Cho, Keun-Seok;Sung, Jong-Mo;Hahn, Min-Soo;Kim, Young-Il;Jeong, Sang-Bae
    • Phonetics and Speech Sciences
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    • v.1 no.4
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    • pp.97-103
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    • 2009
  • This paper describes a new algorithm for encoding spectral envelope in the time domain alias cancellation (TDAC) part of G.729.1. The spectral envelope and modified discrete cosine transform (MDCT) coefficients of the weighted code-excited linear predictive (CELP) coding error in lower-band and the higher-band input signal are encoded in the TDAC part. In order to reduce allocation bits for spectral envelope coding, a new algorithm using sub-band correlation between adjacent frames is proposed. In addition, to improve the quality of decoded signals, two bit allocation strategies using reduced bits from the proposed algorithm are proposed. The performance of the proposed algorithm is evaluated in terms of objective quality and bit reduction rates. Experimental results show that the proposed algorithm increases the quality of sounds significantly.

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Study on Preventing Bit Error of Digital Watermark Using Orthogonal Transform

  • Watanabe, Jun;Hasegawa, Madoka;Kato, Shigeo
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.277-280
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    • 2002
  • Many digital watermarking methods have been proposed for copyright protection. Especially, methods to add a watermark in the frequency domain are often used. In those methods, only a few components of frequencies are changed according to watermark information, so that the pixel values of the image obtained by the inverse transform sometimes exceed the dynamic range and owing to the clipping process at this time watermark information is changed. This phenomenon even occurs without attacks like image processing. In this paper, we propose two methods to prevent loss of watermark information, applicable to such cases, it is said that one is the method called "inversion of increase and decrease" and another is "conservation of amounts of changes." We can extract the watermark information correctly under the condition of no attacks by using these proposed methods.

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Transform Domain Resizing for DCT-Based Codec (DCT 코덱에 기반한 변환 영역에서의 리사이징 알고리즘)

  • 신건식;장준영;강문기
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.3
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    • pp.25-34
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    • 2004
  • The ability to perform the same operations in the transform domain as in the spatial domain is important for efficient image transmission through a channel. We perform image resizing, which includes magnifying and reducing the size, in the discrete cosine transform(DCT) domain and the effects of the transform domain approach are analyzed in the corresponding spatial domain. Based on this analysis, the two resizing algorithms are proposed. The first one further compresses the images encoded by the compression standard by reducing the size before compression, and the other reduces the loss of information while maintaining the conventional compression rate. Because of its compatibility with standard codec, these algorithms can be easily embedded in JPEG and MPEG codecs, which are widely used for the purpose of image storage and transmission. Experimental results show a reduction of about half the bit size with similar image quality and about a 2- or 3-dB quality improvements in the similar compression rate.

An Image Data Compression Algorithm by Means of Separating Edge Image and Non-Edge Image (윤곽선화상과 배경화상을 분리 처리하는 화상데이타 압축기법)

  • 최중한;김해수;조승환;이근영
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.2
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    • pp.162-171
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    • 1991
  • This paper presents an algorithm for compressing image data by separating the image into two parts. I.e. edge image containing high-frequency components and non-edge image containing low-frequency components of image. The edge image is extracted by using 8 level compass gradient masks and the non-edge image is obtained by removing the edge image from the original image. The edge image is coded by Huffman run-length code and the non edge image is transformed first by DCT and the transformed images is coded next by a quantized bit allocation table. For an example image. GIRL. the proposed algorithm shows bit rate of 0.52 bpp with PSNR of 36dB.

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Two-Channel Multiwavelet Transform and Pre/Post-Filtering for Image Compression (영상 데이터 압축을 위한 2-채널 멀티웨이브렛 변환과 전후처리 필터의 적용)

  • Heo, Ung;Choi, Jae-Ho
    • Journal of the Korea Computer Industry Society
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    • v.5 no.5
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    • pp.737-746
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    • 2004
  • Two-channel multiwavelet system is investigated for image compression application in this paper. Generally, multiwavelets are known for their superb capability of compressing non-stationary signals like voice. However, multivavelet system have a critical problem in processing and compressing image data due to mesh-grid visual artifacts. In our two-channel multiwavelet system we have investigated incorporation of pre and post filtering to the multiwavelet transform and compression system for alleviating those ingerent visual artifacts due to multiwavelet effect. In addition, to quantify the image data compression performance of proposed multiwavelet system, computer simulations have been performed using various image data. For bit allocation and quantization, the Lagrange multiplier technique considering data rate vs. distortion rate along with a nonlinear companding method are applied equallly to all systems considered, here. The simulation results have yielded 1 ~ 2 dB compression enhancement over the scalar savelet systems. If the more advanced compression methods like SPIHT and run-length channel coding were adopted for the proposed multiwavelet system, a much higher compression gain could be obtained.

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Design of Bit-Pattern Specialized Adder for Constant Multiplication (고정계수 곱셈을 위한 비트패턴 전용덧셈기 설계)

  • Cho, Kyung-Ju;Kim, Yong-Eun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.11
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    • pp.2039-2044
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    • 2008
  • The problem of an efficient hardware implementation of multiple constant multiplication is frequently encountered in many digital signal processing applications such as FIR filter and linear transform (e.g., DCT and FFT). It is known that efficient solutions based on common subexpression elimination (CSE) algorithm can yield significant improvements with respect to the area and power consumption. In this paper, we present an efficient specialized adder design method for two common subexpressions ($10{\bar{1}}$, 101) in canonic signed digit (CSD) coefficients. By Synopsys simulations of a radix-24 FFT example, it is shown that the proposed method leads to about 21%, 11% and 12% reduction in the area, propagation delay time and power consumption compared with the conventional methods, respectively.

Terabit-Per-Second Optical Super-Channel Receiver Models for Partial Demultiplexing of an OFDM Spectrum

  • Reza, Ahmed Galib;Rhee, June-Koo Kevin
    • Journal of the Optical Society of Korea
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    • v.19 no.4
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    • pp.334-339
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    • 2015
  • Terabit-per-second (Tb/s) transmission capacity for the next generation of long-haul communication networks can be achieved using multicarrier optical super-channel technology. In an elastic orthogonal frequency division multiplexing (OFDM) super-channel transmission system, demultiplexing a portion of an entire spectrum in the form of a subband with minimum power is critically required. A major obstacle to achieving this goal is the analog-to-digital converter (ADC), which is power-hungry and extremely expensive. Without a proper ADC that can work with low power, it is unrealistic to design a 100G coherent receiver suitable for a commercially deployable optical network. Discrete Fourier transform (DFT) is often seen as a primary technique for understanding partial demultiplexing, which can be attained either optically or electronically. If fairly comparable performance can be achieved with an all-optical DFT circuit, then a solution independent of data rate and modulation format can be obtained. In this paper, we investigate two distinct OFDM super-channel receiver models, based on electronic and all-optical DFT-technologies, for partial carrier demultiplexing in a multi-Tb/s transmission system. The performance comparison of the receivers is discussed in terms of bit-error-rate (BER) performance.

An Improvement on FFT-Based Digital Implementation Algorithm for MC-CDMA Systems (MC-CDMA 시스템을 위한 FFT 기반의 디지털 구현 알고리즘 개선)

  • 김만제;나성주;신요안
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.7A
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    • pp.1005-1015
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    • 1999
  • This paper is concerned with an improvement on IFFT (inverse fast Fourier transform) and FFT based baseband digital implementation algorithm for BPSK (binary phase shift keying)-modulated MC-CDMA (multicarrier-code division multiple access) systems, that is functionally equivalent to the conventional implementation algorithm, while reducing computational complexity and bandwidth requirement. We also derive an equalizer structure for the proposed implementation algorithm. The proposed algorithm is based on a variant of FFT algorithm that utilizes a N/2-point FFT/IFFT for simultaneous transformation and reconstruction of two N/2-point real signals. The computer simulations under additive white Gaussian noise channels and frequency selective fading channels using equal gain combiner and maximal ratio combiner diversities, demonstrate the performance of the proposed algorithm.

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