• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.5
• /
• pp.231-241
• /
• 2013

In this paper, we propose an average approximation filter which can effectively remove the noises of the images. The noises include impulse noises, gaussian noises and mixed noises. The algorithm is as follows. First, as a step of noise detection, we find whether the difference between the pixel value and the average value is greater than the threshold value or not after getting the average value that removed the minimum and maximum values in the applied mask. If the pixel value is greater than the threshold value, the pixel value is processed as noise. If it is less than or equal to the threshold value, it is processed as non-noise. Next, as the noise reduction step, we output the approximate value in mask as the pixel value and the average value except the minimum and maximum values of the pixel including the noise. As the result of applying this average approximation filter to the mixed noise images, the approximation filter can reduce the noises effectively more than 0.4[dB] as compared with applying the median filter and the average filter, respectively.

• Journal of Information Technology Application
• /
• v.3 no.2
• /
• pp.133-147
• /
• 2001

This paper proposed a new algorithm for binarization and removal of noises in color images with characters and pictures. Binarization was performed by threshold which had computed with color-relationship relative to the number of pixel in background and character candidates and pre-threshold for dividing of background and character candidates in input images. The pre-threshold has been computed by the histogram of R, G, B In respect of the images, while background and character candidates of input images are divided by the above pre-threshold. As it is possible that threshold can be dynamically decided by the quantity of the noises, and the character images are maintained and the noises are removed to the maximum. And, in this study, we made the noise pattern table as a result of analysis in noise pattern included in the various color images aiming at removal of the noises from the Images. Noises included in the images can figure out Distribution by way of the noise pattern table and pattern matching itself. And then this Distribution classified difficulty of noises included in the images into the three categories. As removal of noises in the images is processed through different procedure according to the its classified difficulties, time required for process was reduced and efficiency of noise removal was improved. As a result of recognition experiments in respect of extracted characters in color images by way of the proposed algorithm, we conformed that the proposed algorithm is useful in a sense that it obtained the recognition rate in general documents without colors and pictures to the same level.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.841-844
• /
• 1999

VDSL noises should be used for testing and evaluation of VDSL systems. In DMT systems for ADSL, noises are generated using IIR filters obtained from the Yule-Walker equations. However, this method cannot be directly applied to VDSL environments. In this paper, an DCT-based VDSL noise generation algorithm is proposed.

• Journal of the Chungcheong Mathematical Society
• /
• v.5 no.1
• /
• pp.23-34
• /
• 1992

This is an extension of results of Wiener's nonlinear noise theory from noises generated by the Wiener process to noises generated by processes with stationary Gaussian increments. In particular, using Nisio's Approach, we show that every measurable ergodic noise can be approximated in law by Gaussian process-presentable noise.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.51 no.3
• /
• pp.432-440
• /
• 2015

The hydro-acoustic technology has been widely used in not only South Korea but also many foreign countries for various scientific purposes. Unfortunately acoustic data especially collected from field surveys may contain noises caused by a variety of sources. Therefore, it is exceedingly important to eliminate noises when acoustic data are analyzed to derive quantitative results. This study introduced two methods for eliminating noises easily and effectively using post-processing software. Used acoustic data were collected on the Jinhae bay and Tongyeong coast of the South Sea in April 2015. The first method, that is the Wang's method, placed emphasis on 'erosion filter' to eliminate only data samples contaminated by noises. The second method (Yamandu's method) focused on the 'resample by number of pings' to remove pings contained noises. To substantiate the effectiveness of two methods, the mean Sv (Volume backscattering strength), mean height and depth of the fish schools detected were compared between before and after using the noise elimination methods. In the Wang's method the mean Sv was decreased from -52.4 dB to -52.9 dB, and in the Yamandu's method from -52.6 dB to -53.3 dB, indicating that noises were successfully eliminated. The mean height (1.5 m) and depth (19.0 m) were same between before and after using two methods showing that the shapes of fish schools were not changed.

• ETRI Journal
• /
• v.36 no.2
• /
• pp.321-324
• /
• 2014

This letter describes a two-phase clock oxide thin-film transistor shift register that executes a robust operation over a wide threshold voltage range and clock coupling noises. The proposed circuit employs an additional Q generation block to avoid the clock coupling noise effects. A SMART-SPICE simulation shows that the stable shift register operation is established for the clock coupling noises and the threshold voltage variation from -4 V to 5 V at a line time of $5{\mu}s$. The magnitude of coupling noises on the Q(15) node and Qb(15) node of the 15th stage is respectively -12.6 dB and -26.1 dB at 100 kHz in the proposed circuit, compared to 6.8 dB and 10.9 dB in a conventional one. In addition, the estimated power consumption is 1.74 mW for the proposed 16-stage shift registers at $V_{TH}=-1.56V$, compared to 11.5 mW for the conventional circuits.

• Journal of Power System Engineering
• /
• v.13 no.4
• /
• pp.43-48
• /
• 2009

The purpose of this study is to show how to eliminate the noises and to obtain the data related with the relationship between AE signal characteristics and mechanical behaviors for the pressure vessel steel. Various kinds of noises are introduced into the AE data in the course of experiments. Accordingly, real AE data have to be obtained after tests. AE test was carried out under four point bending load. Among AE signals, counts and signal strength are used to find out the differences of AE characteristics between the basemetal and weldment. After tests, this paper shows the procedures of filtering the noises against basemetal of the pressure vessel steel to obtain the real data around crack tip. Relationships between plastic zone size and cumulative AE counts are shown also. AE signals were absent within an elastic region, regardless of the specimens. Most of AE signals are produced in the process of plastic deformation. The deformation and fracture modes of basemetal and weldment are quiet different.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.11a
• /
• pp.69-74
• /
• 2006

It is known that the various noise sources which are engine, transmission, tire, intake system, etc exist at vehicle driving status. Specially noises which cannot be expected by a driver induce unpleasantness to all passengers. These noises are difficult to distinguish noise sources or specifications because of too many vehicle parts. Therefore in this paper, study on abnormal noise of bush on suspension system is performed by the measurement and analysis of the noises of bushings that are generated artificially. The measured noises are analyzed by two points-view of spectrum and sound quality. Finally, it is shown that the noise sources of bushings on the suspension system which are the pillow ball joint bush of a control arm and the rubber bush of a lower arm could be distinguished by the spectrum distribution and a index value based on tonality.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.739-742
• /
• 2007

In the step processing multimedia information signals transmitted by a variety of mediums, noises are generated by the internal or exterior causes of systems and these noises degrade the perception about information signals. Therefore, in order to remove noises and restore signals a great number of researches have been progressed and recently, many noise removal methods using time-frequency localization of wavelet have been applied in wide applications. Moreover, when two wavelet bases are designed to accomplish the Hilbert transform pair, wavelet can be efficiently applied to detect characteristics of signals. Therefore, in this paper, in order to restore the corrupted signal by noises, a noise removal algorithm using the Hilbert transform pair of wavelet was proposed.

• The Journal of the Acoustical Society of Korea
• /
• v.18 no.8
• /
• pp.108-115
• /
• 1999

In this study we suggested a digital filter method to enhance car audio sound quality against the sound distortion due to cabin's acoustic characteristics and car driving noises. The digital filters designed were based on the characteristics on car driving noises and cabin acoustic characteristics. Car driving noises were analyzed by two ways; one is an objective method, octave band frequency analysis method. The other is a subjective method; sensory evaluation method, NCB method. On these results, seven sets of modified coefficients of eleven band digital filters were obtained. To find optimum audio sound quality among nine sound samples filtered by designing seven types of digital filters, which were mixed car driving noises at 100km/h, subjective evaluation method was used, paired comparison method; Scheffe' seven point method.