Browsing by Author "CHU, CH"

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AN ADAPTIVE ENHANCEMENT ALGORITHM FOR QUANTIZED IMAGES
(1994-05-01)
CHU, CH
;
HSUEH, YC
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
When high-quality images are displayed by low-level graphics devices, they must be re-quantized. Many quantization algorithms have been proposed to solve this problem. However, the fine details cannot manifest themselves in the quantized images by the general quantization-algorithms. In this paper, an adaptive technique is proposed to enhance the quantized images such that the fine features such as edges, thin lines, and curves are more visible. By tuning a threshold value, the desired patterns used to produce the visual impression of grayscale information at constant and small varying areas can be preserved and the high frequency information can made more visible.
FEGE LIQUID-METAL ION-SOURCE FOR MASKLESS ISOLATION IMPLANTS IN INP
(1992-07-01)
CHU, CH
;
BARR, DL
;
HARRIOTT, LR
;
WADE, HH
;
奈米中心
A Fe-Ge alloy was used to fabricate a liquid metal ion source (LMIS) for our focused ion beam system. The iron ion and germanium ions can be utilized to create semi-insulating regions for device isolation and n-type doping in InP. The properties of the Fe-Ge LMIS were characterized by measuring the ion current-extraction voltage characteristics, the mass spectrum of the ion species in the ion beam, and the stability of the source current. The changes of resistivity in InP before and after Fe + + implant and after thermal annealing were measured in mesa-etched four-terminal test structures. The resistivity of as-implanted samples increases about four orders of magnitude compared with original resistivity. After rapid thermal annealing at 400-degrees-C for 10 s, the resistivity is about two times larger than that of as-implanted sample.
FORMATION OF EXCELLENT SHALLOW N+P JUNCTIONS BY AS+ IMPLANTATION INTO THIN COSI FILMS ON SI SUBSTRATE
(1993-04-01)
LIN, CT
;
JUANG, MH
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CHU, CH
;
CHENG, HC
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電子工程學系及電子研究所
Excellent shallow n + p junctions with a leakage current density of about 0.6 nA/cm2 have been fabricated by As+ implantation into thin CoSi films on Si substrates and subsequent drive-in/silicidation. The resultant junction characteristics are strongly affected by the implant conditions. A deeper as-implanted dopant profile is more helpful to drive the dopant within the silicides into the junction regions. Because the silicidation facilitates damage annihilation, the implant conditions forming excellent junctions in this scheme own large process window and thus yield low thermal budgets. Rapid thermal annealing was not favorable to forming junctions in this scheme because of its short annealing times for the arsenic drive-in.
IMAGE COMPRESSION BY CARDINALITY DISTRIBUTION
(1994-09-01)
CHU, CH
;
CHERN, MG
;
HSUEH, YC
;
資訊工程學系
;
Department of Computer Science
Cardinality distribution is an efficient technique to display images with different gray level systems. In this paper, we extend the application of cardinality distribution to image compression. Image is first quantized to an image with fewer gray levels. Because the cardinality-distributed images possess the desired dithering patterns, the quantized images have the more compact forms. In the decompression, gray level expansion by cardinality distribution is proposed to reconstruct the images. Therefore, cardinality distribution not only has the ability to quantize images with different gray levels but also has the potential to compress images.
IMAGE REQUANTIZATION BY CARDINALITY DISTRIBUTION
(1991)
HSUEH, YC
;
CHERN, MG
;
CHU, CH
;
交大名義發表
;
資訊工程學系
This article presents a new approach to image requantization, called cardinality distribution. The new method introduces dithering patterns as ordered dither does; however, it provides a smoothing parameter p between 0 and 1. When p is chosen to be near 0.5, the new method can capture very sharp details of images. Therefore, the major deficiency of ordered dither can be avoided. Moreover, the reordering technique and its modified version are used to code bilevel and higher gray-level requantized images, respectively.
INTERFACIAL REACTIONS OF TITANIUM THIN-FILMS ON ION-IMPLANTED (001) SI
(1993-04-01)
LIAUH, HR
;
CHEN, MC
;
CHEN, JF
;
CHEN, LJ
;
LUR, W
An investigation on the influences of doping impurities on the formation of titanium silicide has been carried out. The formation of polycrystalline silicide was observed to be retarded by the presence of As in Ti/As+-Si samples compared with those in Ti/BF2+-Si samples. Superior thermal stability of TiSi2 was found to occur in BF2+ implanted samples than that in blank and As+ implanted samples. The resistance to island formation in BF2+ implanted samples is attributed to the retardation of grain growth by the segregation of fluorine atoms at the grain boundaries.
QUANTIZATION-ERROR CURVE - A MEASURE OF SIMILARITY BETWEEN REQUANTISED IMAGES
(1994-03-31)
CHU, CH
;
HSUEH, YC
;
資訊工程學系
;
Department of Computer Science
A new similarity measure between a digital image and its quantised version is presented. By calculating the quantisation error on each of a sequence of subdomains, we can obtain a quantisation error curve as a similarity measure. This measure outperforms the commonly used measure for estimating the similarity between requantised images.