• Title/Summary/Keyword: digital signal process

Search Result 527, Processing Time 0.027 seconds

Image Restoration for Edge Preserving in Mixed Noise Environment (복합잡음 환경에서 에지 보존을 위한 영상복원)

  • Long, Xu;Kim, Nam-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.18 no.3
    • /
    • pp.727-734
    • /
    • 2014
  • Digital processing technologies are being studied in various areas of image compression, recognition and recovery. However, image deterioration still occurs due to the noises in the process of image acquisition, storage and transmission. Generally in the typical noises which are included in the images, there are Gaussian noise and the mixed noise where the Gaussian noise and impulse noise are overlapped and in order to remove these noises, various researches are being executed. In order to preserve the edge and effectively remove mixed noises, image recovery filter algorithm was suggested in this study which sets and processes the adaptive weight using the median values and average values after noise judgment. Additionally, existing methods were compared through simulations and PSNR(peak signal to noise ratio) was used as a judgment standard.

Modified Gaussian Filter Considering Noise Characteristics in AWGN Environments (AWGN 환경에서 잡음 특성을 고려한 변형된 가우시안 필터)

  • Cheon, Bong-Won;Kim, Nam-Ho
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.20 no.3
    • /
    • pp.125-131
    • /
    • 2019
  • Through the 4th Industrial Revolution, various digital equipments are being distributed, and accordingly, the importance of data processing is increasing. As data processing has a great effect on the reliability of equipment, its importance is increasing, and various studies are being conducted. In this paper, we propose an algorithm to remove AWGN in consideration of the noise in the image. The proposed algorithm is used in the filtering process by inferring the standard deviation of the image noise. The noise is removed by dividing the filter for the high frequency component and the filter for the low frequency component compared with the standard deviation of the filtering mask. The proposed algorithm is simulated with the existing methods for evaluation and compared and analyzed by difference image, PSNR and profile. The proposed algorithm minimizes the effect of noise and preserves the important characteristics of the image and shows the performance of efficient noise removal.

Analysis of Leakage Current of a Laser Diode by Equivalent Circuit Model (등가회로 모델에 의한 레이저다이오드의 누설전류 해석)

  • Choi, Young-Kyu;Kim, Ki-Rae
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.11 no.2
    • /
    • pp.330-336
    • /
    • 2007
  • A single pixel photon counting type image sensor which is applicable for medical diagnosis with digitally obtained image and industrial purpose has tern designed with $0.18{\mu}m$ triple-well CMOS process. The designed single pixel for readout chip is able to be operated by single supply voltage to simplify digital X-ray image sensor module and a preamplifier which is consist of folded cascode CMOS operational amplifier has been designed to enlarge signal voltage(${\Delta}Vs$), the output voltage of preamplifier. And an externally tunable threshold voltage generator circuit which generates threshold voltage in the readout chip has been newly proposed against the conventional external threshold voltage supply. In addition, A dark current compensation circuit for reducing dark current noise from photo diode is proposed and 15bit LFSR(Linear Feedback Shift Resister) Counter which is able to have high counting frequency and small layout area is designed.

The Design of a Wind Speed & Direction Module and a DSP Sensor Interface System for the Meteorological System (기상계측시스템을 위한 풍향.풍속모듈 및 DSP 센서 인터페이스시스템 설계)

  • Song, Do-Ho;Joo, Jae-Hun;Ock, Gi-Tae;Kim, Sang-Gab;Choi, Jung-Keyng
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.11 no.8
    • /
    • pp.1478-1485
    • /
    • 2007
  • In this paper, a meteorological system including a wind speed & direction module and the DSP(Digital Signal Processor) sensor interface circuit board are proposed. This DSP system accepts and process the informations from a wind speed & direction module, the atmospheric pressure sensor, the ambient air temperature sensor and transfers it to the PC monitoring system. Especially, a wind speed & direction module and a DSP hardware are directly designed and applied. A wind speed & direction module have a construction that it have four film type RID(Resistive Temperature Detectors) resistive sensor adhered around the circular metal body heated constantly by heating coil for obtaining vector informations about wind. By this structure, the module is enabled precise measurement having a robustness about vibration, humidity, corrosion. A sensor signal processing circuit is using TMS320F2812 TI(Texas Instrument) Corporation high speed DSP. An economical meteorological system could be constructed through the data from wind speed & direction module and by the fast processing of DSP interface circuit board.

A Study on Modified Adaptive Weighted Filter in Mixed Noise Environments (복합잡음 환경에서 변형된 적응 가중치 필터에 관한 연구)

  • Kwon, Se-Ik;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2014.10a
    • /
    • pp.798-801
    • /
    • 2014
  • Nowadays, the demand for multimedia services has grown with the rapid evolution in the digital era. But due to external causes in the process of processing, transmitting and storing image data, the images are damaged. One of the major causes of such damage is known to be noise. Some of the most commonly used methods for removing noise are CWMF(center weighted median filter), A-TMF(alpha-trimmed mean filter) and AWMF(adaptive weighted median filter). However, these filters all leave a bit to be desired in removing noise in a complex noise environment. Therefore this paper suggest an image restoration filter algorithm that first judges the noise and sets a adjustment weight based on the median value and distance of the mask to remove the complex noise. For an objective analysis, the results were compared against existing methods and the PSNR(peak signal to noise ratio) was used as a reference.

  • PDF

Design of High-Speed Sense Amplifier for In-Memory Computing (인 메모리 컴퓨팅을 위한 고속 감지 증폭기 설계)

  • Na-Hyun Kim;Jeong-Beom Kim
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.18 no.5
    • /
    • pp.777-784
    • /
    • 2023
  • A sense amplifier is an essential peripheral circuit for designing a memory and is used to sense a small differential input signal and amplify it into digital signal. In this paper, a high-speed sense amplifier applicable to in-memory computing circuits is proposed. The proposed circuit reduces sense delay time through transistor Mtail that provides an additional discharge path and improves the circuit performance of the sense amplifier by applying m-GDI (: modified Gate Diffusion Input). Compared with previous structure, the sense delay time was reduced by 16.82%, the PDP(: Power Delay Product) by 17.23%, the EDP(: Energy Delay Product) by 31.1%. The proposed circuit was implemented using TSMC's 65nm CMOS process, while its feasibility was verified through SPECTRE simulation in this study.

Development of the Inductive Proximity Sensor Module for Detection of Non-contact Vibration (비접촉 진동 검출을 위한 유도성 근접센서모듈 개발)

  • Nam, Si-Byung;Yun, Gun-Jin;Lim, Su-Il
    • Journal of the Korea Society of Computer and Information
    • /
    • v.16 no.5
    • /
    • pp.61-71
    • /
    • 2011
  • To measure the fatigue of metallic objects at high speed vibration while non-contact precision displacement measurement on how to have a lot of research conducted. Noncontact high-speed vibration detection sensor of the eddy current sensors and laser sensors are used, but it is very expensive. Recently, High-speed vibrations detection using an inexpensive inductive sensor to have been studied, but is still a beginner. In this paper, a new design of an inexpensive inductive proximity sensor has been suggested in order to measure high frequency dynamic displacements of metallic specimens in a noncontact manner. Detection of the existing inductive sensors, detection, integral, and amplified through a process to detect the displacement noise due to weak nature of analog circuits and integral factor in the process of displacement detection is slow. The proposed method could be less affected by noise, the analog receive and high-speed signal processing is a new way, because AD converter (Analog to Digital converter) without using the vibration frequency signals directly into digital signals are converted. In order to evaluate the sensing performance, The proposed sensor module using non-contact vibration signals were detected while shaker vibration frequencies from 30Hz to 1,100 Hz at intervals of vibrating metallic specimens. Experimental results, Vibration frequency detection range of the metallic specimins within close proximity to contactless 5mm could be measured from DC to 1,100Hz and vibration amplitude of the resolution was $20{\mu}m$. Therefore, the proposed non-contact inductive sensor module for precision vibration detection sensor is estimated to have sufficient performance.

A Study on Image Restoration in Gaussian Noise Environment (가우시안 잡음환경하에서 영상복원에 관한 연구)

  • Seo, Hyun-Soo;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2007.06a
    • /
    • pp.205-208
    • /
    • 2007
  • Due to the development and wide use of digital multimedia broadcasting (DMB) and Wireless Broadband Internet (WiBro), the digital contents industry using images has been progressed. Therefore, the image processing has been applied in a variety of fields and in order to transmit and conserve accurate information, the degradation phenomenon for images should be removed. As a representative cause of the degradation phenonenon, noise has become known and Gaussian noise occurs in the process of transmission. Diverse researches for Gaussian noise removal have been implemented and a great number of algorithms have been proposed until now. In this paper, for mage restoration an algorithm using the adaptive threshold value is proposed in Gaussian noise environment and the threshold value is established by using the histogram of edge image. And from simulation results, the noise removal performance of the proposed method is proven using mean square error (MSE) and peak signal to noise ratio (PSNR).

  • PDF

A Digital Automatic Gain Control Circuit for CMOS CCD Camera Interfaces (CMOS CCD 카메라용 디지털 자동 이득 제어 회로)

  • 이진국;차유진;이승훈
    • Journal of the Korean Institute of Telematics and Electronics C
    • /
    • v.36C no.5
    • /
    • pp.48-55
    • /
    • 1999
  • This paper describes automatic gain control circuit (AGC) design techniques for CMOS CCD camera interface systems. The required gain of the AGC in the proposed system is controlled directly by digital bits without conventional extra D/A converters and the signal settling behavior is almost independent of AGC gain variation at video speeds. A capacitor-segment combination technique to obtain large capacitance values considerably improves the effective bandwidth of the AGC based on switched-capacitor techniques. A proposed layout scheme for capacitor implementation shows AGC matching accuracy better than 0.1 %. The outputs from the AGC are transferred to a 10b A/D converter integrated on the same chip. The proposed AGC is implemented as a sub-block of a CCD camera interface system using a 0.5 um n-well CMOS process. The prototype shows the 32-dB AGC dynamic range in 1/8-dB steps with 173 mW at 3 V and 25 MHz.

  • PDF

Effects of Accelerometer Signal Processing Errors on Inertial Navigation Systems (가속도계 신호 처리 오차의 관성항법장치 영향 분석)

  • Sung, Chang-Ky;Lee, Tae-Gyoo;Lee, Jung-Shin;Park, Jai-Yong
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.9 no.4
    • /
    • pp.71-80
    • /
    • 2006
  • Strapdown Inertial navigation systems consist of an inertial sensor assembly(ISA), electronic modules to process sensor data, and a navigation computer to calculate attitude, velocity and position. In the ISA, most gryoscopes such as RLGs and FOGs, have digital output, but typical accelerometers use current as an analog output. For a high precision inertial navigation system, sufficient stability and resolution of the accelerometer board converting the analog accelerometer output into digital data needs to be guaranteed. To achieve this precision, the asymmetric error and A/D reset scale error of the accelerometer board must be properly compensated. If the relation between the acceleration error and the errors of boards are exactly known, the compensation and estimation techniques for the errors may be well developed. However, the A/D Reset scale error consists of a pulse-train type term with a period inversely proportional to an input acceleration additional to a proportional term, which makes it difficult to estimate. In this paper, the effects on the acceleration output for auto-pilot situations and the effects of A/D reset scale errors during horizontal alignment are qualitatively analyzed. The result can be applied to the development of the real-time compensation technique for A/D reset scale error and the derivation of the design parameters for accelerometer board.