• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.12
• /
• pp.2337-2342
• /
• 2008

In this paper, we propose the novel approach to enhance the visual quality of the digital image with adaptively sharpening and removing the noise. Image enhancement is performed in two ways. The pixels in the high dynamics area are sharpened by the adaptive unsharp mask with the parameter, which is derived using the statistical information of the image. On the other hand, the proposed algorithm do not perform the sharpening process in the uniform area that may cause the undesired artifact due to noise amplification, rather it performs smoothing to suppress the noise in this area. The decision, which process will be applied at the pixel, is also controlled by the statistics of the pixel dynamics. The proposed algorithm enhances the visual quality almost automatically by sharpening and smoothing at the same time with less parameter selection.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.30 no.2
• /
• pp.131-137
• /
• 2014

Purpose: This study examined the efficiency and wear of periodontal instrument sharpening using aluminum oxide stones with different levels of roughness. Materials and Methods: Thirty new No. 9-10 Gracey curets were used in this study. All curets had become dull after scaling and root planing. After similar blunting, the instruments were divided randomly into three groups (240, 600, 800 grit) containing 10 curets each. The stones were applied correctly to the lateral surface of each curet to maintain the $70-80^{\circ}$ angle. After resharpening, sharpness of the curets was examined by an optical microscope. After 20, 40, 60, and 80 strokes, the wear was measured at 1 mm and 2 mm from the tip of the cutting edge using a digital caliper. The data was analyzed statistically using analysis of variance (ANOVA) with repeated measures, 2-way ANOVA, and a Fisher's exact test. Results: The degree of sharpness increased significantly (P < 0.001) as the number of sharpening strokes grew for all stones. A comparison of the degree of sharpness on the same number of strokes showed that the 240 grit group significantly excelled the other groups on 5 and 10 strokes, respectively (P < 0.001). The mean wear showed no statistically significant difference among the groups (P > 0.05). Conclusion: The efficiency of Gracey curet resharpening was enhanced with more coarse stones, though we should consider the wear of the instrument during resharpening.

• Journal of the Korean Society for Precision Engineering
• /
• v.24 no.3 s.192
• /
• pp.31-39
• /
• 2007

• The Pure and Applied Mathematics
• /
• v.15 no.1
• /
• pp.93-101
• /
• 2008

In this article we shall characterize the Heinz-Kato-Furuta inequality in several ways, and the best bound for sharpening of the inequality is obtained by the method in [7].

• Communications of the Korean Mathematical Society
• /
• v.34 no.1
• /
• pp.203-211
• /
• 2019

In this note, new sharpened Redheffer type inequalities related to the Fox-Wright functions are established. As consequence, we show new Redheffer type inequalities for hypergeometric functions and for the four-parametric Mittag-Leffler functions with best possible exponents.

• Journal of Korea Multimedia Society
• /
• v.7 no.2
• /
• pp.164-172
• /
• 2004

Halftoning of gray-scale image is a process to produce a binary image. The error diffusion halftoning method produces high qualify binary image but that has some defects such as sharpening and directional artifacts. We propose the threshold modulation to reduce such defects. The proposed algorithm uses thresholds reflecting local characteristic of image. We calculate thresholds which minimize errors of flat region of each gray-scale level by using a linear gain between original image and error-diffused image and then represent edge by compensating thresholds in proportion to edge information. The proposed method improves on halftone quality by minimizing an error which cause sharpening and directional artifact.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.33 no.6
• /
• pp.517-526
• /
• 2015

Among the various image fusion or pan-sharpening methods, those wavelet-based methods provide superior radiometric quality. However, the fusion processing is not only simple but also flexible, since many low- and high-frequency sub-bands are often produced in the wavelet domain. To address this issue, a novel DT-CWT (Dual-Tree Complex Wavelet Transform) proportional to the fusion method by a WZP (Wavelet Zero-Padding) is proposed. The proposed method produces a single high-frequency image in the spatial domain that is injected into the LRM (Low-Resolution Multispectral) image. Thus, a wavelet domain fusion can be simplified to spatial domain fusion. In addition, in the proposed DT-CWTP (DT-CWT Proportional) fusion method, it is unnecessary to decompose the LRM image by adopting WZP. The comparison indicates that the proposed fusion method is nearly five times faster than the DT-CWT with SW (Substitute-Wavelet) fusion method, meanwhile simultaneously maintaining the radiometric quality. The conducted experiments with WorldView-2 satellite images demonstrated promising results with the computation efficiency and fused image quality.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.5
• /
• pp.1524-1533
• /
• 1996

Risidual stress of cylindrical glass rods are measured by photoelasticity to study the variation of stresses with respect to heat treatment temperatures. In order to measure the stresses accurately, fringe sharpening and multiplication techniques are applied to the determination of photoelastic fringe orders. Filon's separationmethod is used to resolve circumferential and redial stress ocmponents from isochromatic fringes which are the same as in-plane maximum shearing stresses. According to the photoelastic measurements, residual stress is increased as the heat treatment temperature of the rods is raised from $560^{\circ}C$ to $650^{\circ}C$ All the circumferential stress components are changed from tensile stresses to compressive ones at approximate $R_m$/$R_o$ = 0.6, where $R_o$/ is outer radius and $R_m$any measured radius. This analysis shows that residual stresses of the glass rods approach zero if the rods are heat-treated near the strain point.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.8C
• /
• pp.811-820
• /
• 2003

In this paper, multi-watermarking algorithm is proposed to satisfy two purpose of ownership protection and tamper proofing simultaneously. At first, for robust watermarking, the location of the embedding wavelet coefficient is selected by using existing QSWT algorithm. And then, we propose the method inserting discrete cosine transformed watermark. The watermarked image is watermarked again for the tamper proofing. The tamper proofing algorithm is also proposed. According to the experimental results, the proposed multi-watermarking algorithm is robust to the attack, such as blurring, sharpening, JPEG compression. And also, the tampered area are detected in blocks, making it simple to judge which pixels are changed.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.15 no.2
• /
• pp.113-122
• /
• 2005

In this paper, we propose a multi-watermarking algorithm to satisfy two purposes: fragility against malicious attacks and robustness against non-malicious attacks. The algorithm can be used for image authentication using coefficients of Discrete Wavelet Transform(DWT). In the proposed method, watermarks are generated by combining binary image with some features extracted from the subband LL3, and then they are embedded into both the spatial and frequency domain. That is, on the spatial domain they are embedded into the Least Significant Bit(LSB) of all pixels of image blocks, and on the frequency domain the coefficients of the subband LH2 and HL2 are adjusted according to the watermarks. Thus the algorithm not only resists malicious attack but also permits non-malicious attacks such as blurring, sharpening, and JPEG compression.