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標題: 以邊緣偵測為限制的半色調誤差擴散
Error Diffusion Halftoning with Error Confinement by Edge Detection
作者: Yi-Wen Fang
關鍵字: Halftoning
error diffusion
heat transfer
edge detection
引用: [1] Yang, B., Lei, L., & Yang, J. “HVS-based structural image quality assessment model.”, 7th World Congress on Intelligent Control and Automation , pp. 8497-8500. 2008. [2] Floyd, R.W. and Steinberg, L. “An Adaptive Algorithm for Spatial Gray Scale.”, International Symposium Digest of Technical Papers, vol. 1975m, pp. 36-37, 1975. [3] Damera-Venkata, N., & Evans, B. L. “Design and analysis of vector color error diffusion halftoning systems.” IEEE Tran. Image Processing, pp. 1552-1565, Oct. 2001. [4] Li, P., & Allebach, J. P. “Tone-dependent error diffusion.” Image Processing, IEEE Tran. pp. 201-215, Feb. 2004. [5] Pei, S. C., & Guo, J. M. “Hybrid pixel-based data hiding and block-based watermarking for error-diffused halftone images. ” Circuits and Systems for Video Technology, IEEE Tran. pp. 867-884, Aug. 2003. [6] Chang, T. C., & Allebach, J. P. “Quantization of accumulated diffused errors in error diffusion. Image Processing,” IEEE Tran. pp.1960-1976, Dec. 2005. [7] Jarvis, J. F., & Roberts, C. “A new technique for displaying continuous tone images on a bilevel display. Communications,” IEEE Tran. pp. 891-898, Aug. 1976. [8] Stucki. P. “MECCA-a multiple-error correcting computation algorithm for bilevel image hardcopy reproduction,” Research Report RZ1060, IBM Research Laboratory, Zurich, Switzerhand, 1981. [9] Shiau, J. N. & Fan, Z. “Set of easily implementable coefficients in error diffusion with reduced worm artifacts. ” In Electronic Imaging: Science & Technology. International Society for Optics and Photonics. pp. 222-225, March. 1996. [10] Alex, N. S. & Anbarasi, L. J. “Enhanced image secret sharing via error diffusion in halftone visual cryptography.” In Electronics Computer Technology (ICECT), 2011 3rd International Conference on (Vol. 2,). IEEE Tran, pp. 393-397 , April. 2011. [11] Zhu, Z., Wang, Y. & Jiang, G. “On Perceptually Consistent Image Binarization. ”Signal Processing Letters, IEEE Tran, pp. 3-6 , Jan. 2013.
摘要: 現今印刷設備所列印的圖像,只能藉由著墨或不著墨來表現層次,半色調技術為使打印影像呈現效果良好所衍生產物。基本原理是將連續灰階轉換為二值化圖像,在處理過程中結合人眼視覺效果,利用人眼具有低通濾波的特性,在一定的距離下觀察,會產生連續圖像的錯覺,可藉此改善影像品質。半色調技術有很多學者提出方法改善影像呈現的品質,主要方法從技術上可大約分三大類:點處理、鄰域處理、迭代法。 本篇研究,我們針對鄰域處理中的誤差擴散方法,其方法在影像呈現容易產生蟲效應(worm effect)和隨機性紋理兩大問題進行改良。在本研究中使用了誤差擴散方法「熱擴散」,利用擴散距離改變其誤差擴散係數,並在擴散處理中,限制影像邊緣擴散方向與改變擴散方向權重,此方法的改良可以改善誤差擴散的缺失,使得最後呈現結果更為接近連續色調圖像。此方法可適用於任何二值化的設備上,處理效率也頗快速,呈現優良的輸出圖像品質。
Most modern printing devices can only express on/off states in each pixel on the paper. To express gradual intensity level for printed images, halftoning techniques are developed. Its principle is to utilize the low-pass filtering characteristics of human visual system by averaging multiple black/white pixels into a grayscale area when viewing from a distance. After a long period of researches, the halftoning techniques can be divided into three categories: point process, neighborhood process, and iterative process. The focus of this thesis is to improve the error diffusion algorithm in neighborhood process. The main disadvantages of error diffusion are the reproduced images exhibit worm effects and periodic texture patterns. In this thesis, we improve an error diffusion method using heat transfer theory to adjust diffusion coefficients according to diffusion distance. The feature we add is to use edges in an image to limit the diffusion direction and dynamically adjust diffusion coefficients. By adding this new feature, we show in experiments that the new algorithm can produce better looking halftone images as compared to previous methods.
文章公開時間: 2015-07-18
Appears in Collections:通訊工程研究所



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