DISCOVERING LEGIBLE AND READABLE CHINESE TYPEFACES FOR READING DIGITAL DOCUMENTS BING ZHANG A THESIS IN THE DEPARTMENT OF COMPUTER SCIENCE AND SOFTWARE ENGINEERING PRESENTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF COMPUTER SCIENCE AT CONCORDIA UNIVERSITY MONTREAL, QUEBEC, CANADA AUGUST 2011 © BING ZHANG, 2011 CONCORDIA UNIVERSITY School of Graduate Studies This is to certify that the thesis prepared By: Bing ZHANG Entitled: Discovering Legible and Readable Chinese Typefaces for Reading Digital Documents and submitted in partial fulfillment of the requirements for the degree of Master of Computer Science complies with the regulations of the University and meets the accepted standards with respect to originality and quality. Signed by the final examining committee: _______________________________Chair Dr. R. Jayakumar _______________________________Examiner Dr. T. Kasvand _______________________________Examiner Dr. C. Lam _______________________________ Supervisor Dr. Ching Y. Suen Approved by __________________________________________ Chair of Department or Graduate Program Director __________ 20_____ __________________________________________ Dr. Robin A. L. Drew, Dean Faculty of Engineering and Computer Science ii ABSTRACT DISCOVERING LEGIBLE AND READABLE CHINESE TYPEFACES FOR READING DIGITAL DOCUMENTS BING ZHANG Concordia University In recent years, more and more fonts have been implemented in the digital publishing industry and in reading devices. In this thesis, we focus on the methods of evaluating digital Chinese fonts and their typeface characteristics. Our goal is to seek a good way to enhance the legibility and readability of Chinese characters displayed on digital devices such as cell phones, tablets and e-book devices. To accomplish this goal, we have combined methods in data mining, and pattern recognition with psychological and statistical analyses. Our research involved an extensive survey of the distinctive features of eighteen popular Chinese digital typefaces. Survey results were tabulated and analyzed statistically. Then, two objective experiments were conducted, using the best six fonts derived from the survey results. These experimental results have revealed an effective way of choosing legible and readable Chinese digital fonts that are most suitable for the comfortable reading of books, magazines, newspapers, and for the display of texts on cell-phones, e-books, and digital libraries. Results also helped us find out the features for improving character legibility and readability of different Chinese typefaces. The relationships among legibility, readability, eye-strain, and myopia, will be discussed. Moreover, digital market requirements and analyses will be provided. iii ACKNOWLEDGEMENTS It is a pleasure to thank many people who helped me accomplish this thesis a lot. Their helps to me not only is to finish my current study, but helping my life’s study as well. What I learnt from my supervisor are not only the expertise and research ideas, but also the research among human, including communication, negotiation, cooperation and so on. Thus, firstly I would like to appreciate the helps sincerely from my dear supervisor, Dr. Ching Y. Suen, for his suggestive instruction, persistent guidance, warm encouragement and continuous support. Without his help and support, my study would not have been accomplished. I feel extremely lucky to have been supervised by Dr. Suen, and it is my honor to work with him. Moreover, I have to say thank you to all my colleagues and staff in the Center for Pattern Recognition and Machine Intelligence (CENPARMI), for providing a positive, optimistic and studious environment in which to learn and grow. Especially, I am really grateful to Guiling Guo, Ying Li, Xiaoxiao Niu, Xiaohua Xie, and Chao Yao. They are all my “family members” in CENPARMI, and they taught me a lot in both study and living. A special thanks to the research manager of CENPARMI, Mr. Nicola Nobile, for his technical support and assistance, and to Ms. Shira Katz, for her editing and proofreading of this thesis. Also I want to say thank you to our office assistants, Ms. Marleah Blom, for her administrative assistance. iv Then, I wish to say thank you to my parents, for their constant moral support. I am very thankful to them for all they have given me in my life, for sharing ups and downs, and for reminding me, when necessary. Last but not least, I am very thankful to everyone who has directly and indirectly helped me, in any way, to accomplish this research. v Table of Contents Chapter 1. Introduction ................................................................................................... 1 1.1 Background ..................................................................................................... 1 1.2 Motivation ....................................................................................................... 5 1.3 Objective ....................................................................................................... 10 1.4 Current Chinese typefaces ............................................................................. 12 1.4.1 Character shape ....................................................................................... 14 1.4.2 Character blackness ................................................................................. 19 1.5 Thesis Outline ................................................................................................ 21 Chapter 2. Survey of Human Preference of Fonts ........................................................ 22 2.1 Survey Description ........................................................................................ 22 2.2 Structural Design ........................................................................................... 23 2.3 Detailed Design ............................................................................................. 24 2.3.1 Subjective Questions Design ................................................................... 24 2.3.2 Objective Experiment Design: ................................................................ 26 2.4 Survey Results and Analysis ......................................................................... 28 Chapter 3. Legibility Analysis ...................................................................................... 33 3.1 Data Collection .............................................................................................. 33 3.2 Participants .................................................................................................... 36 vi 3.3 Materials and Equipment ............................................................................... 36 3.3.1 Data Preprocessing .................................................................................. 36 3.3.2 Equipment ............................................................................................... 37 3.4 SCFRT procedure .......................................................................................... 37 3.4.1 Data Processing ....................................................................................... 38 3.4.2 Tests of Within-Subjects Effects ............................................................. 40 3.4.3 Pairwise Comparisons ............................................................................. 46 3.5 Discussion ..................................................................................................... 53 Chapter 4. Readability Experiment .............................................................................. 56 4.1 Studied Chinese Fonts ................................................................................... 56 4.2 Materials ........................................................................................................ 57 4.3 Experimental Results ..................................................................................... 60 4.3.1 Analysis of reading speed ....................................................................... 61 4.3.2 Comprehension Analysis......................................................................... 68 4.4 Discussion ..................................................................................................... 72 4.4.1 FZHT vs. FZWB ..................................................................................... 72 4.4.2 FZHT vs. WRYH .................................................................................... 74 Chapter 5. Simulation and Verification of Machine OCR ........................................... 78 5.1 Simulation of the Single Character Recognition ........................................... 78 vii 5.1.1 Test data .................................................................................................. 79 xProjectionmethod ......................................................................................... 79 5.1.2 Data preprocessing .................................................................................. 80 5.1.2.1 Binarization ......................................................................................... 80 5.1.2.2 Image Smoothing ................................................................................ 80 5.1.2.3 Normalization ..................................................................................... 82 5.1.3 Feature Extraction ................................................................................... 83 5.1.3.1 Gradient Features