Dissertations / Theses on the topic 'Halftoning'
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Aijazi, Ahmed Tausif. "Hybrid Color Halftoning." Thesis, Linköping University, Department of Science and Technology, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-56737.
Full textHalftoning methods can be divided into two main categories, namely AM (Amplitude Modulated) and FM (Frequency Modulated). Some printing methods, such as Flexography, are not able to produce dots small enough to handle the highlights and the shadows of the original image by just using AM halftoning method. To overcome this problem FM method is used in the highlights (and the shadows) and an AM method in rest of the image.
Hybrid halftoning (combination of AM and FM) technique for grayscale images has already be presented showing the best way to place FM and AM dots in the resulting binary image. This thesis work is and extension of that and presents hybrid technique for color images. In color images, besides the problem of transition area between AM and FM, a number of other factors needs to be addressed. One of such factors is to define the starting point of FM technique in different color channels. In this work all the possibilities of combining AM and FM in different color channels have been investigated and then the best approach for hybrid color halftoning is proposed. This approach not only uses the best solution for starting point of FM halftoning in each channel but also places the different color dots in the highlights, as homogenously as possible.
Streit, Lisa M. "Importance driven halftoning." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34422.pdf.
Full textGustavsson, Oscar. "Inverse Halftoning Using Inverse Methods." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-96225.
Full textLiu, Chen. "Multilevel halftoning over hexagonal grids." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.85 Mb., 47 p, 2006. http://wwwlib.umi.com/dissertations/fullcit/1435813.
Full textVeryovka, Oleg. "Texture control in digital halftoning." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0016/NQ46940.pdf.
Full textGooran, Sasan. "High quality frequency modulated halftoning /." Norrköping : Univ, 2001. http://www.bibl.liu.se/liupubl/disp/disp2001/tek668s.pdf.
Full text莫紹祥 and Siu-cheung Mok. "Parametric halftoning and image reconstruction." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B31208800.
Full textMok, Siu-cheung. "Parametric halftoning and image reconstruction /." [Hong Kong : University of Hong Kong], 1988. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1243713X.
Full textUlichney, Robert. "Digital halftoning and the physical reconstruction function." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15079.
Full textMICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: p. 397-405.
by Robert A. Ulichney.
Ph.D.
Dong, Chen-Koung. "Measurement of printer parameters for model-based halftoning." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12812.
Full textGonzalez, Alvaro J. "Alpha stable human visual system models for digital halftoning." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 58 p, 2007. http://proquest.umi.com/pqdweb?did=1251904881&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textGonçalves, Cristhiane. "Elemento óptico difrativo de luz branca gerado por computador." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18155/tde-07032008-075335/.
Full textHolograms can be produced using traditional holography techniques or may be also generated by computer, which are known as CGHs(Computer-generated holograms). Most of these holograms operate using monochromatic light. On the other hand, holograms can also operate with white light. These white light holograms are used in several applications, such as security, to verify the autencity of credit cards end other documents, because their fabrication processes are dificult to reproduce and are expensive. However, convencional white light holograms operate based on reflection of light, and present some undesirable effects, like chromatic distortions, such as rainbow effect. In this work it was proposed a computer-generated phase optical difractive element designed to operate under white light illumination. The element is calculated based on the halftoning technique and in the partial spatial coherence of a white light extended source. Phase elements are manufactured using well-established integrated circuits fabrication techniques and optical simulations are shown. No iterative methods are necessary. Simulated and optical reconstructions results are very similar and produce good clear images, and no chromatic distortions are observed. The white light element was not yet described on literature, and some of its applications may be an optical correlator or holographic art. This work was carried at the laboratory of optics of the department of electrical engineering of the EESC, and supported by CAPES (Coordenadoria de Aperfeiçoamento dePessoal de Nível Superior).
Schmaltz, Christian [Verfasser], and Joachim [Akademischer Betreuer] Weickert. "Kompression, Pose-Tracking und Halftoning / Christian Schmaltz. Betreuer: Joachim Weickert." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2012. http://d-nb.info/1052338283/34.
Full textŽitinski, Elías Paula. "Halftoning for Multi-Channel Printing : Algorithm Development, Implementation and Verification." Licentiate thesis, Linköpings universitet, Medie- och Informationsteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-112271.
Full textYu, Jin Nah. "Video dithering." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/505.
Full textDamera-Venkata, Niranjan. "Analysis and design of vector error diffusion systems for image halftoning /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004247.
Full textIvan, Pinćjer. "Razvoj dinamičkog modela kontrole procesnih parametara postupaka rastriranja i njihov uticaj na otisak kao stimulus." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2016. http://www.cris.uns.ac.rs/record.jsf?recordId=96011&source=NDLTD&language=en.
Full textThe research presented in this dissertation is related to the image reproduction qualityassessment. Dissertation was designed to determine the impact of halftone attributeson image quality. Objective and subjective quality assessment results were designedto complement recently published findings for quality assessment. These attributes aredirectly dependent on the chosen halftoning method. In this research the samples werehalftoned using two different types of screening methods: frequency modulated andamplitude modulated method. Experiment data samples, were analysed by adequatestatistical methods. Results indicate significant influence of halftoning method on thequality assessment and defines control model.
Nilsson, Daniel. "Mikrolitografi för rastrerade Gobos." Thesis, Linköping University, Department of Science and Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2861.
Full textBeacon AB has been producing Gobos for some time. A Gobo is a small round sheet used in projectors almost like a slide. It is used mostly in the commercial and entertainment business. Today these Gobos are created by using a film (also called mask). A digital exposure machine called LIOS has been developed to make it possible to create Gobos using direct exposure. This means a film will no longer be necessary and it will also make the process faster and cheaper.
To be able to use LIOS in the industry a lot of work still has to be done. An image is sent to the display in LIOS. This image comes from a computer connected to LIOS and at the end of the process it will be reproduced on the Gobo. This image can be modified before it is sent to LIOS so that a better result can be achieved in the end. The problem is that once the process is complete the image will be binary, which means halftoning is going to be used. The goal of the research described in this paper is first to test the properties of LIOS, second to create a halftoning method especially designed for those properties.
The resultof this thesis is an AM (Amplitude Modulated) method that uses a modified threshold matrix. Using this method would not give a satisfying result unless some of the distortions could be corrected somehow. This can however be done using a property available for the display in LIOS. The display can handle grayscales but since etching is used later in the process the final result will be a binary image (only black and white). This means that even though the image will be binary in the end, these grayscales can still be used to improve the result. The equipment that was available when this thesis was done was not fully developed why the grayscales are used to correct distortions.
The resulting method will most likely be good enough to produce Gobos with a satisfying quality. The method has never been used before and it introduces a new way of making corrections for halftoning. There are still some practical problems left to solve before LIOS can be used to reliably produce Gobos. Using better equipment can solve several of these problems but not all of them.
Ilbery, Peter William Mitchell Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Scanline calculation of radial influence for image processing." Publisher:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/42784.
Full textKite, Thomas David. "Design and quality assessment of forward and inverse error diffusion halftoning algorithms /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Full textŽitinski, Elías Paula. "Improving image quality in multi-channel printing - multilevel halftoning, color separation and graininess characterization." Doctoral thesis, Linköpings universitet, Medie- och Informationsteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-134939.
Full textAxelson, Per-Erik. "Quality Measures of Halftoned Images (A Review)." Thesis, Linköping University, Department of Science and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1138.
Full textThis study is a thesis for the Master of Science degree in Media Technology and Engineering at the Department of Science and Technology, Linkoping University. It was accomplished from November 2002 to May 2003.
Objective image quality measures play an important role in various image processing applications. In this paper quality measures applied on halftoned images are aimed to be in focus. Digital halftoning is the process of generating a pattern of binary pixels that create the illusion of a continuous- tone image. Algorithms built on this technique produce results of very different quality and characteristics. To evaluate and improve their performance, it is important to have robust and reliable image quality measures. This literature survey is to give a general description in digital halftoning and halftone image quality methods.
Eriksson, Robert, and Daniel Fridh. "Implementation av iterativ rastreringsmetod för färgbilder." Thesis, Linköping University, Department of Science and Technology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1395.
Full textThis report describes the procedure in which we accomplished our task, which was to implement a present algorithm. This was made using C++. The algorithm is developed by Sasan Gooran, who is our examiner in this project. The algorithm uses an iterative method to produce the halftoned images.
The reason for this project is to speed up the existing program which is made in Matlab. Our main action taken to speed up the program was to use C++ instead of Matlab. It is safe to say that we managed to fulfill our commitments with respect to speed, but we are not completely satisfied with the results regarding the quality. Although the result does not differ a great deal compared to the Matlab version, there are still improvements to make before considering using it commercially.
Our program is an extension of an existing C++ program, written by Per Fredriksson. We used his program as base to our program. The addition we have made to his code is the possibility to halftone colour images.
Kora, Venugopal Rishvanth. "FPGA BASED PARALLEL IMPLEMENTATION OF STACKED ERROR DIFFUSION ALGORITHM." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/40.
Full textGräf, Manuel. "Efficient Algorithms for the Computation of Optimal Quadrature Points on Riemannian Manifolds." Doctoral thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-115287.
Full textChao, Tsi-Yi, and 趙子毅. "Color Inverse Halftoning." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/14220016740605976793.
Full text國立交通大學
電子研究所
83
Color halftoning is a very popular technique for producing printed pictures with only two levels for each color. Our goal in this research is to find a good color inverse halftoning algorithm. There are two types of input images to the inverse halftoning system : (1) ideal digital halftoned image data, and (2) sampled image data from a scanner. When the received halftone images are ideal digital data, we can simply apply the previous obtained monochrome inverse halftoning techniques to each color component separately and achieve rather satisfactory results. The situation is rather different in recovering gray- scale images from the scanned images. To this end, we develop the printer and the scanner models and two types of reconstruction methods to recover the original gray-scale image from the scanned image. In the first method, the reconstruction filter is derived directly from the scanned data and the ideal original gray-scale image. In the second method, the forward halftoning, the printing and the scanning process are reversed one by one. Either approach seems to produce reasonably good results. Further improvement on the scanner model and the recovery of gray-scale images need to be investigated.
Ye, Shiang-Rung, and 葉向榮. "Random Position Orthography Halftoning." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/59521663552994576386.
Full text輔仁大學
資訊工程學系
87
Orthography halftoning is one of the old digital halftoning algorithms. It replaces each pixel in a continuos-tone image with an M by N font. The advantage of orthography algorithm is that when we need to scale up a continuous-tone image before applying halftoning algorithm to the image, orthography algorithm can do both things at the same time, which shortens the processing time considerably. But orthography halftoning algorithm does possess disadvantages. Because orthography algorithm uses only one font to reproduce one gray level, the textures, created from a uniform area, exhibit structure or fixed pattern. It is also common to see some dramatic texture in the halftoned image depending on selected fonts. In this paper, we propose an algorithm to solve these problems. The algorithm uses multiple fonts, which can reproduce the same gray level, to reproduce one gray level. Those fonts are created at run-time for each pixel in the image by putting desired dots into the font randomly.
Tai, Yu-feng, and 戴裕豐. "Halftoning image descreening using SWT." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/39433117718618327310.
Full text國立中央大學
資訊工程學系碩士在職專班
100
Due to the rapid growth of 3C mobile devices, such as iPad and iPhone, the emerging of ebook becomes a trend accordingly. Users can scan traditional paper books into ebook and read it in iPad or iPhone. It further creates business opportunity and add-on value for traditional publishing industries. In printing technology, digital contents have to be transformed into halftone format for printing purpose. However, it will result in some unwanted effects when we inverse the scanned image into its original digital image file. The most serious effects are moire and print grid. It hence deteriorates image quality and cause uncomfortable viewing quality. The reason is that the halftone fine patterns will result in image tone intermittent and thereby influence the perception of human vision seriously. In this thesis, we focus our research on improving the viewing quality of halftoning image. Firstly, we will describe the principle of digital halftoning and the forming of moire and rosette patterns. We will also present the objective method of estimating descreening image quality at the same time. Then, a method that inverses halftone images using wavelet transform is proposed.The comparison between stationary wavelet transform and discrete wavelet transform is also given. Last, experiments were conducted on various images to illustrate the influences of wavelet families that were used in halftoning process. Experimental results demonstrate the superiority of our method.
Ong, Qi-Xuan, and 翁啟軒. "Digital Image Inverse Halftoning Techniques." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/38653870056702472850.
Full text中原大學
電機工程研究所
100
Most of printers use halftone technology to show the effects of gray scales on printed outputs. In this paper, we will discuss several main halftone techniques, and discuss why these technologies have visual effects of gray scales. When we scan the information on printed, documents and save them as files, we sometimes want to do image compression or other image processings. For this purpose, we need to convert halftone images back to grayscale images such that do image processings more conveniently. This technology is called inverse halftoning. Since halftone technology is a distortion image processing method, we can’t exactly original image, but to approximate as closely to original images. This thesis will discuss the five inverse halftoning methods: least mean square(LMS), LMS minimum mean square error(LMS-MMSE), least-squares (LS),the regional variance classification training filter and Gaussian filter methods. And we will compare the differences between those methods. For the first four methods we need the statistics of training samples to find appropriate inverse halftone values. Finally in the paper, we propose to do sample classifications based on the gaps of edges and edge directions. We then use the set after classifications to construct the LS filters whose resulting inverse halftoning images are closer to original images.
Tsai, Jia-jin, and 蔡嘉晉. "Data Hiding with Digital Halftoning." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/03577597331417767888.
Full text國立臺灣科技大學
電機工程系
97
The digital information over Internet have been growing rapidly recently. Digital multimedia can easily be downloaded or manipulated and tampered intentionally. So the intellectual property protection becomes more important. Most multimedia is stored in compressed bit stream format to save the storage space or transmission time. This thesis proposes two novel techniques for data hiding, data hiding in halftoning images and data hiding in grayscale images, respectively. Notably, the proposed data hiding in grayscale images can also achieve compression benefit. First, this thesis presents a reasonable computational complexity data hiding algorithm to embed secret pattern into two or more halftone images. The former approaches in the literature do not consider noise strength according to the local variance value. The proposed Adaptive Noise-Balanced Error Diffusion (ANBEDF) method employs the Quality-Noise Look Up Table (QNLUT) and the optimized multipliers to control the adaptive noise strength according to the local variance value. The experimental results show that higher decoding rate is available under the same image quality performance than former approaches in the literature. Moreover, this thesis proposes another data hiding which can embed flexible amount of data in the bit map of an Ordered Dither Block Trumcation Coding(ODBTC)image, where the ordered dithering is used to dither the quantized BTC image to avoid the annoying false contour and blocking effect inherently existed in BTC image. Experimental results demonstrate that an objective good image quality image with flexible capacity and reasonable complexity is obtained. Moveover, the correct decoding rate of 100% is maintained, and the original host ODBTC image can also be reconstructed in the decoder when needed.
Chen, Li-Ming, and 陳立明. "Inverse Halftoning for Monochrome Pictures." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/08728637612983083442.
Full text國立交通大學
電子研究所
82
Two basic inverse halftoning methods together with some post- processing schemes are proposed in this thesis. In order to optimize the inverse operation of halftoning, we first take the inverse modeling concepts to find the least-squares solutions of this problem. And then, the knowledge of image characteristics can help us in designing improved algorithms that produce the most promising pictures to our eyes. They are conceptually very different from the traditional inverse half- toning methods that use simple low-pass filters. Furthermore, we develop a general space-varying sliding-window filter (SV- SWF) scheme. The goal is to handle various types of pictures using the same basic inverse halftoning structure together with adaptive parameters. This universal inverse halftoning operator is achieved by using an adequate classification scheme to separate image data into different groups, each corresponding to a set of pre-trained parameters. It is proven through detailed analysis on the performance of the proposed algorithms that these algorithms produce better reconstructed images than the other known algorithms in both PSNR and subjective evaluation.
(6631334), Wanling Jiang. "COLOR HALFTONING BASED ON NEUGEBAUER PRIMARY AREA COVERAGE AND NOVEL COLOR HALFTONING ALGORITHM FOR INK SAVINGS." Thesis, 2019.
Find full textA halftoning method with Neugebauer Primary Area Coverage direct binary search (NPAC-DBS) is developed. With the optimized human visual system (HVS) model, we are able obtain homogeneous and smooth halftone colored image. The halftoning is based on separating the colored image represented in Neugebauer Primary in three channels based on human visual system, with swap-only DBS, we arrange the dots to bring the error metric to its minimum and the optimized halftone image is obtained. The separation of chrominance HVS filters between red-green and blue-yellow channels allows us to represent HVS more accurately. Color halftone images generated using this method and method of using traditional screening methods are compared.
In order to speed up the halftone process with similar quality of NPAC-DBS, we developed PARAWACS screens for color halftoning. PARAWACS screen is designed level by level using DBS. With PARAWACS screen, we can create halftone using simple pixel by pixel comparison with the merit of DBS. We further optimized the screen to achieve the best quality.
Next, a novel halftoning method that we call Ink-Saving, Single-Frequency, Single-Angle, Multi-Drop (IS-SF-SA-MD) halftoning is introduced. The application target for our algorithm is high-volume production ink-jet printing in which the user will value a reduction in ink usage. Unlike commercial offset printing in which four-colorant printing is achieved by rotating a single screen to four different angles, our method uses a single frequency screen at a single angle, and it depends on accurate registration between colorant planes to minimize dot-overlap especially between the black (K) colorant and the other colorants (C, M, and Y). To increase the number of gray levels for each colorant, we exploit the multidrop capabilities of the target writing system. We also use the hybrid screening method to yield improved halftone texture in the highlights and shadows. The proposed method can help preserve ink significantly.
Shen, Hui-Ru, and 沈惠如. "Inverse Halftoning for Error Diffused Images." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/31527775672888293237.
Full text國立交通大學
資訊科學學系
86
In this thesis, new inverse halftoning methods for error diffused images are proposed. In the proposed Method 1, we designed a weight matrix for inverse halftoning error diffused images by means of the least-mean-square error algorithm. Then with this specific weight matrix, we can reconstruct the gray value from the error diffused image. To save the reconstruction time, we modified Method 1 and proposed Method 2. To improve further the reconstruction image quality, we proposed Method 3, which is a classified method. In Method 3, we classify the input pixels in the error diffused image into two categories, i.e., edge and uniform regions. For these two categories, we adopt different process methods. Our experiments show that Method 2 can get good recovered image quality in very short time. If we requires better image quality, Method 3 can be a substitution for Method 2.
Lin, Chun-ming, and 林俊名. "Sampling and Halftoning of 3D Meshes." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/94467365436278666349.
Full text龍華科技大學
電機工程研究所
96
This thesis focuses on sampling and halftoning of the polygonal 3D models. First of all, this thesis proposes a new three-dimensional sampling technique for the 3D models consist of polygonal meshes, under the principles of trying not to destroy the 3D model’s primitive topology and accelerating the processing speed. Then, for the sampling results, a new three-dimensional error-diffusion halftoning technique is propsed to dither the sample points to show the tonal illusion on the 3D model’s surface. Obviously, the experimental results demonstrate the feasibility of the proposed techniques.
Chi, Chen Chia, and 陳家麒. "Color Images Halftoning for Printer Application." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/95270721561976979561.
Full text逢甲大學
資訊工程學系
87
Color printers do not have the capability of printing continuous-tone color images. They usually have only four inks (Cyan, Magenta, Yellow, and Black). Obviously, they can not represent all colors of a color image. Traditional error-diffusion algorithm is proposed for solving this problem. In general, error-diffusion produces acceptable halftoned images. Unfortunately, it also produces some artifacts, i.e. unstable phenomenon and smeared edges. These situations are much worse when dot overlap is included. In this paper, we use a series of methods to improve the quality of halftoned color images displayed by printers with dot overlap. First, we show that the traditional error-diffusion algorithm may become stable if a proper formula is used to determine the color difference and propose a stable error-diffusion algorithm that does not consider the dot overlap. Then, we modify this error-diffusion algorithm as a new one to include dot overlap. We also present a dot-size estimation method for this algorithm. Finally, the edge enhancement function is added into our error-diffusion algorithm. Halftoning a color image by our proposed error-diffusion algorithm with edge enhancement has the following characteristics: the unstable phenomenon does not exit; the color-error caused by dot overlap is corrected; and the smeared edges are sharpened.
Cai, Jyun-Teng, and 蔡浚騰. "Inverse Halftoning Based on Data Classification." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/78182150819328170392.
Full text中原大學
通訊工程碩士學位學程
103
Halftoning technology is a method to convert gray-level images to binary images. Well-known haftoning technologies will be introduced in Chpater 2. Inverse halftoning is a technology to reconstruct continuous tone images from halftone images. Because it is a method based on pattern-training to estimate gray-level values, it is classified as am distorted image. In Chapter 3, we introduce recent inverse halftoning technologies based on pattern training including LMS and LS. Then we will discuss inverse halftoning based on data classification. First we will introduce a recent well-known method: variance classification by Guo. In Chapter 4, we discusss inverse halftoning methods based on Sobel operator and Laplacian edge data classifications. In Ong’s paper, 397 filters are trained by Sobel edge classification. In this thesis we will discuss methods to reduce filter numbers, and compare to Laplacian edge classification. Experiment results of inverse halftoning based on data classifications will be discussed and showed in the end.
Chen, Chien-Hung, and 陳建宏. "HEVC Intra Prediction with Halftoning Technique." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/69233322861263759572.
Full text國立中央大學
通訊工程學系
103
In order to predict more accurately, High Efficiency Video Coding, the latest standard of video compression, has 33 different directions in intra prediction, so we can get better coding performance. However, the characteristic of single directionality has not changed. There is still plenty of room for improvement in complex texture image. To improve coding performance of intra prediction, the inpainting technique[1] has been studied but it is impractical because of its high computational complexity. In [2], Error diffusion is applied to HEVC intra prediction. It can improve the quality of prediction images by extending the information of bilateral reference pixels to them with only a little increase of time consumption. In addition, It still has 20% increase of encoding time, so we improve it in this paper. The improving error diffusion just need 5%, and the coding performance can be better. Except for the error diffusion, there is another technique named ordered dithering which come from Halftoning. We apply it to HEVC intra prediction. The results demonstrate that average 0.5% BDBR reduction can be achieved, and only need 3% increase of encoding time in the proposed algorithm, compared to HEVC intra prediction.
Kuo, Ya-Hui, and 郭雅惠. "Image-switching Watermark by Digital Halftoning." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/86573879026796615480.
Full textYu, Tai-Kuang, and 余泰廣. "Watermarking by green noise halftoning technique." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/86286830411764876922.
Full text"Digital halftoning and the physical reconstruction function." Massachusetts Institute of Technology, Research Laboratory of Electronics, 1986. http://hdl.handle.net/1721.1/4223.
Full textOriginally presented as author's thesis (Ph. D.--Massachusetts Institute of Technology), 1986.
Bibliography: p. 397-405.
"This work has been supported by the Digital Equipement Corporation."
Chen, Yaw-Kuang. "DIGITAL HALFTONING BY USING IMAGE LOCAL FEATURE." 1992. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0009-0112200611301331.
Full textLin, Li-Ming, and 林禮銘. "Digital Image Halftoning Techniques and Watermark Hiding." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/91941885198917056387.
Full text中原大學
電機工程研究所
99
Most black and white printers use screentone technology to simulate the gray color. In fact, it composes of a large number of two-toned black and white dots. Since the human eyes can not scrutinize these dots, after the human eye it will produce the illusion of gray, which is the so-called halftone technique. Examples include inkjet printers, fax machines, newspapers, magazines, and comic books printing. Most of them use halftone images as outputs. This thesis first reviews order dither, error diffusion, dot diffusion and other existing halftoning techniques. We will explore techniques to convert the gray-scale image into a halftone image and compare their advantages and disadvantages. Information encryption is often discussed in this network age. A technology to hide watermark in an image to transmit the secrete watermark information is also an information encryption method. Because the information amount is less for halftone images than for grayscale and color images, transmission of halftone images can reduce the time required. Chapter 3 will explore the use of stochastic error diffusion, noise-balanced error diffusion, and other methods to hide the watermark in the error diffused halftone pictures. Finally, we propose new methods to hide watermarks in two halftone images. Specifically, we propose to use threshold changes to hide watermarks in order dither halftone images. We also propose to change error diffusing orders of the dot diffusion halftoning technique to hide the watermarks.
Chang, Jia-Yu, and 張嘉裕. "Aperiodic Digital Halftoning and Its Multitoning Extension." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/89123990395977219781.
Full text國立臺灣科技大學
電機工程系
101
In this thesis, three techniques, including two improved digital halftoning algorithms and one digital multitoning algorithm, are proposed to convert images for output devices. Digital halftoning is a technique for converting continuous-tone images into limited-tone images. The distortion between an original image and the converted image is inevitable, since the number of the corresponding output levels is less than the continuous-tone. Thus, the main object of the halftoning is to reduce the distortion induced from this transformation. Nowadays, the processing performance of the halftoning has become a critical issue as the image resolution is increasing. Another key element of this thesis is to effectively boost the processing efficiency. The first proposed method is the Multiple Look-Up Table (MLUT) which is based on the look-up table halftoning, and is an effective technique for yielding satfactory image quality. According to the experiment results, the dot distribution generated by the proposed method can approximate to the well-known direct binary search halftoning which can achieve the best image quality so far, and thus it can be a very competitive candidate in coping printing industry. The second proposed method is the Content-Dependent Dot Diffusion (CDDD) which is based on Dot Diffusion (DD). The proposed CDDD can provide better image quality and a near aperiodic characteristic simultaneously comparing to the former parallel methods. The multitoning is a technique which extends the halftoning by adopting more than two quantification levels for reducing the distortion between an original image and the converted image. Yet, the banding effect disturbs the visual perception, and thus degrades the image quality. To improve the image quality by removing the banding effect, the third method termed Tone-Replacement Error Diffusion multitoning (M-TRED), is proposed. According to the experimental results, the proposed method can provide excellent tone-similarity and dot-distribution simultaneously comparing to the former banding-free methods in the literature.
Hsu, Chao-Yung, and 許朝詠. "Security Issues in SIFT and Video Halftoning." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/94674894203200988782.
Full text國立臺灣大學
電機工程學研究所
100
With the advances in mobile device and cloud computing technologies, cloud computing provider focuses on providing various multimedia applications as services to mobile device users. The new type of multimedia application is changing people’s life. On the other hand, it also lead to several multimedia security issues. In this dissertation, the multimedia security issues will be described. For a mobile device, video halftoning is a key technology for use in electronic paper (e-paper) or smart paper, which is an emerging display device that has received considerable attention recently. In this dissertation, a temporal frequency of flickering-distortion optimized video halftoning method is proposed. We first uncover three visual defects that conventional neighboring frame referencing-based video halftoning methods, due to their sequential changes of reference frames, will encounter. To deal with the problem, we then propose a reference frame update per GOP-based error diffusion video halftoning method based on a flickering sensitivity-based human visual model. To efficiently compromise between average temporal frequency of flickering (ATFoF) and visual quality, temporal frequency of flickering-distortion (TFoFD) is presented as a metric for video halftoning performance evaluation. Based on the proposed probability model of video halftoning, the TFoFD curve can be accurately estimated to optimize the tradeoff between quality and ATFoF before the video is halftoned. Our temporal frequency of flickering-distortion optimization strategy can also be applied to other video halftoning schemes for performance improvement. With the advances in mobile device and cloud computing technologies, people are getting used to accessing and querying multimedia data in the cloud environment. Scale space image feature extraction (SSIFE) has been widely adopted in multimedia security and other applications for cloud service. However, the security threat to SSIFE-based media security applications, which will be addressed in this thesis, is relatively unexplored. The security threat, composed of a constrained-optimization keypoint inhibition attack (KIHA) and a keypoint insertion attack (KISA), is specifically designed in the proposed method for scale-space feature extraction methods such as SIFT and SURF. The principle of KIHA is to make a fool of feature extraction protocols in that the detection rules are purposely violated so that no local maximum can be found around in a local region. On the other hand, KISA is designed to create the false positive problem. Our method is evaluated and compared with Do et al.’s method (ACM MM’10), which also figures out the weakness of our previous work (ACM MM’09). In addition, our proposed security threat is applied to an image copy detection method operated on a web-scale image database for performance evaluation. In addition, privacy has received considerable attention but is still largely ignored in the multimedia community. Consider a cloud computing scenario where the server is resource-abundant and is capable of finishing the designated tasks. It is envisioned that secure media applications with privacy preservation will be seriously treated. In view of the fact that scale-invariant feature transform (SIFT) has been widely adopted in various fields, this dissertation is the first to target the importance of privacy-preserving SIFT (PPSIFT) and to address the problem of secure SIFT feature extraction and representation in the encrypted domain. As all of the operations in SIFT must be moved to the encrypted domain, we propose a privacy-preserving realization of the SIFT method based on homomorphic encryption. In our method, homomorphic comparison is a key component for PPSIFT feature detection, but it is still a challenging issue for homomorphic encryption methods, like the Paillier cryptosystem. To solve this problem, the idea here is to investigate a homomorphic comparison strategy via quantization. We also analyze the error probability of feature extraction due to a scaling factor being introduced to realize an integer DoG transform in the Paillier cryptosystem. Moreover, we show through the security analysis based on the discrete logarithm problem and RSA that PPSIFT is secure against ciphertext only attack and known plaintext attack. Experimental results obtained from different case studies demonstrate that the proposed homomorphic encryption-based privacy-preserving SIFT performs comparably to original SIFT and that our method is useful in SIFT-based privacy-preserving applications.
Wu, Shih-tung, and 吳世通. "Inverse Halftoning and Watermarking of Halftone Images." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/62024988355940130483.
Full text國立臺灣科技大學
資訊工程系
96
Halftones are dedicated for output devices, such as halftone printers and palette-based displays that are capable of producing only a limited number of colors. Halftones have been widely used in the publishing applications, such as newspapers, books, magazines, etc. In this thesis, inverse halftoning and watermarking of halftone images are presented. Inverse halftoning algorithm is used to reconstruct the gray image from the input halftone image. Based on the recently published lookup table (LUT) technique, a novel edge-based LUT method for inverse halftoning is proposed for increasing the quality of the reconstructed gray image. The experimental results demonstrate the better image quality of the proposed edge-based LUT method when compared to the Mese and Vaidyanathan algorithm. Based on the proposed edge-based LUT inverse halftoning algorithm, a color inverse halftoning algorithm is proposed. Color inverse halftoning algorithm can transform color halfotnes to full color image. Previously, Mese and Vaidyanathan proposed an efficient LUT-based color inverse halftoning algorithm using the color correlations among different color planes to improve the quality of the reconstructed color images. The proposed algorithm first demonstrates that although the Mese and Vaidyanathan algorithm produces good quality reconstruction of color pixels in non-smooth regions, the quality of reconstructed color pixels in smooth regions may be degraded. Therefore, a new LUT color inverse halftoning algorithm using an adaptive color correlation scheme is presented to improve the quality of reconstructed color images. The experimental results demonstrate the proposed algorithm achieves better reconstructed image quality than that of the Mese and Vaidyanathan algorithm. Due to the growth of internet and digital media, the issue of data hiding becomes more and more important since hiding data into digitized images has many applications, such as authentication, identification, annotation, and copyright protection, etc. Among these digitized images, halftone images, text images, and mixed text/halftone (MTH) images are three widely used binary document images. A unified min-max transition (MMT)-based data hiding algorithm for mixed text/halftone images is proposed to embed data into MTH images without visual degradation. The experimental results demonstrate that for MTH images, our proposed algorithm outperforms the previous relevant algorithms. In addition, for embedding data into halftone images or text images, our proposed algorithm is quite competitive to the previously algorithms.
Chiang, Cheng-Kuo, and 蔣政國. "Design of Digital Halftoning System for LCD." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/14453338078229525478.
Full text中華大學
電機工程學系碩士班
91
The revolution in digital applications has made a complete change in ways of thinking, methods of working and living, etc. The low price, and continuing to be lower than ever, of the liquid crystal display (LCD) is one of the advantages of applying digital consumer products. In practice, the LCD on the market displays red-green-blue (RGB) color pictures of 24 bpp (bits per pixel) with a lower resolution of 18 bpp (6 bpp for each color) by using the so-called halftone techniques. The commonly used digital halftone methods are: noisy encoding, ordered dithering and error diffusion. In this thesis, the performances of the widely used halftone methods mentioned above are compared thoroughly based on the experimental results. And, a new digital halftoning by combining the error diffusion with the dispersed ordered dithering is proposed to improve the display performance. This combination structure has the advantages of both the error diffusion and ordered dithering. Experimental results show that the combined error diffusion and ordered dithering outperforms any of the individual methods. In addition, the issue of hardware implementation of the proposed combined digital halftoning is also investigated in this thesis.
Liu, Zhi Xuan, and 劉至萱. "A non-separable model for color halftoning." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/94955459437505694006.
Full textJing, Ming-Chih, and 井明智. "Inverse Halftoning Algorithm Using Linear Estimation and Denoising." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/80127576986871911492.
Full text大葉大學
資訊工程學系碩士班
95
This paper proposes the use of linear estimation to restore a halftone image into a grayscale image. The proposed method consists of the following steps: （1） Input a grayscale training image and its halftone image then classify the pixels of the halftone image into one of 18 categories. （2） Use the linear estimation method to estimate the best weight mask filter for each pixel. （3） Input the test halftone image and classify each pixel. （4） Process each pixel through the best weighting mask filter for their type to acquire the restored inverse halftone image. （5） Use the Wavelet-based Inverse Halftoning via Deconvolution （WInHD） method to acquire the final restored image. Classification is performed by applying the Gaussian smoothing filter to the halftone image to derive the grayscale image. Canny edge detection is then applied to the image to derive the binary edge image. Finally, the edges from the pixel’s 25 neighboring points are taken into account to classify it into one of 18 categories. The experimental results showed that the PSNR quality of the image restored using the proposed method was on average 0.55dB higher than WInHD and ELUT. With the Lena image for example, the proposed method generated an inverse halftone image with a PSNR or 32.80dB.
Chow, Yeh, and 卓曄. "Texture-Reserving Image Halftoning using Q'tron Neural Networks." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/60577965388894139696.
Full text大同工學院
資訊工程學系
84
Neural networks have become a very popular field of research in computer science, signal processing, optics, and physics. They represent a very broadrange of neural processing models. An artificial neural network is an abstractsimulation of a real nervous system that contains a collection of neural unitscommunicating with each other via axon connections. Such a model bears a strong resemblance to axons and dendrites in a nervous system. Due to its self-organizing and adaptive nature, the model potentially offers a new parallelprocessing paradigm that could be more robust and use-friendly than thetraditional approaches.Artifical neural networks draw many applications in the field of image processing, such as segmentation, edge detection, restoration, compression, andhalftoning of images. In the thesis, we propose a neural network (NN) modelcalled a Q' tron NN for texture-preserving image halftoning. The neurons in suchan NN are connected in cellular sense. In order to preserve the outstandingtextures of images, the connection matrix of the NN was built by incorporatingthe moment feature of an images into the energy function of that NN. As the NN is running, it tends to minimize the energy of this term, which serves to minimize the moment variation of the original image and the halftone one. This will restrict the pixels in the halftone image to be aligned in the same formatas the texture patterns. The second central moment of image is considered in the research. To vertify the feasibility of the approach, several experiments are conducted on a digital computer. The experimental images include the artificially made graphical images and real images.
Gao, Jun-Chun, and 高俊淳. "Digital Image Halftoning Based on Extended Dot Diffusion." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/xspnx9.
Full text中原大學
通訊工程碩士學位學程
105
In the past, traditional digital image halftoning techniques, such as order-dither, error diffusion, dot diffusion methods, transform continue-tone images into images with only two binary gray levels 0 and 255. It uses the human visual system property that makes halftone images look like continue-tone images. As to the digital image inverse halftoning technique, it converts halftone images to continue-tone images. It has been widely used for image processing such as edge detection, sharpening, and compression. This research focuses on digital image halftoning based on extended dot diffusion and inverse halftoning based on K-means clustering. Digital image halftoning based on extended dot diffusion combines order-dither and three kinds of dot diffusions as Knuth, Mese and Guo’s halftoning techniques. It utilizes the threshold matrix rather than one fixed threshold to improve the efficiency of processing. The method of measuring the quality of image is PSNR(Peak Signal to Noise Ratio). Digital image halftoning based on extended dot diffusion gets better image quality than the Knuth’s dot diffusion and better processing efficiency than each of them. Inverse halftoning based on K-means clustering takes the advantage of the easy algorithm and clustering, which brings it better classification results. This research compares the inverse halftoning based on K-means clustering with the Sobel and Laplacian data edge classifications, as well as the LMS and LS inverse halftoning techniques, and then the results are analyzed.