Pickup usability dominates: a brief history of mobile text entry research and adoption

Text entry on mobile devices (e.g. phones and PDAs) has been a research challenge since devices shrank below laptop size: mobile devices are simply too small to have a traditional full-size keyboard. There has been a profusion of research into text entry techniques for smaller keyboards and touch screens: some of which have become mainstream, while others have not lived up to early expectations. As the mobile phone industry moves to mainstream touch screen interaction we will review the range of input techniques for mobiles, together with evaluations that have taken place to assess their validity: from theoretical modelling through to formal usability experiments. We also report initial results on iPhone text entry speed

An investigation into the use of linguistic context in cursive script recognition by computer

The automatic recognition of hand-written text has been a goal for over thirty five years. The highly ambiguous nature of cursive writing (with high variability between not only different writers, but even between different samples from the same writer), means that systems based only on visual information are prone to errors. It is suggested that the application of linguistic knowledge to the recognition task may improve recognition accuracy. If a low-level (pattern recognition based) recogniser produces a candidate lattice (i.e. a directed graph giving a number of alternatives at each word position in a sentence), then linguistic knowledge can be used to find the 'best' path through the lattice. There are many forms of linguistic knowledge that may be used to this end. This thesis looks specifically at the use of collocation as a source of linguistic knowledge. Collocation describes the statistical tendency of certain words to co-occur in a language, within a defined range. It is suggested that this tendency may be exploited to aid automatic text recognition. The construction and use of a post-processing system incorporating collocational knowledge is described, as are a number of experiments designed to test the effectiveness of collocation as an aid to text recognition. The results of these experiments suggest that collocational statistics may be a useful form of knowledge for this application and that further research may produce a system of real practical use

On-line recognition of connected handwriting

Computer technology has rapidly improved over the last few years, with more powerful machines becoming ever smaller and cheaper. The latest growth area is in portable personal computers, providing powerful facilities to the mobile business person. Alongside this development has been the vast improvement to the human computer interface, allowing noncomputer- literate users access to computing facilities. These two aspects are now being combined into a portable computer that can be operated with a stylus, without the need for a keyboard. Handwriting is the obvious method for entering data and cursive script recognition research aims to comprehend unconstrained, natural handwriting. The ORCHiD system described in this thesis recognises connected handwriting collected on-line, in real time, via a digitising pad. After preprocessing, to remove any hardware-related errors, and normalising, the script is segmented and features of each segment measured. A new segmentation method has been developed which appears to be very consistent across a large number of handwriting styles. A statistical template matching algorithm is used to identify the segments. The system allows ambiguous matching, since cursive script is an ambiguous communications medium when taken out of context, and a probability for each match is calculated. These probabilities can be combined across the word to produce a ranked list of possible interpretations of the script word. A fast dictionary lookup routine has been developed enabling the sometimes very large list of possible words to be verified. The ORCHiD system can be trained, if desired, to a particular user. The training routine, however, is automatic since the untrained recognition system is used as the basis for the trained system. There is therefore very little start-up time before the system can be used. A decision-directed training approach is used. Recognition rates for the system vary depending on the consistency of the writing. On average, the untrained system achieved 75% recognition. After some training, average recognition rates of 91% were achieved, with up to 96% observed after further training

Examining the effects of sub-word processing units on the time-course of typewriting

Contrary to models of speech production and handwriting, models of typewriting lack an account of processing of sub-word units (i.e. processing that occurs after the writer / speaker has started to output the word). This thesis examines factors that affect the time-course of production of sub-word letter strings. The first series of experiments examined letter-chunking in typewriting. Participants repeatedly typed short letter-stings, manipulated for trigram and bigram frequency. Onset latency was shorter for high frequency bigrams and trigrams relative to low-frequency controls. Latencies were also shorter for the second keystroke in higher frequency bigrams. These findings can be interpreted as providing strong evidence that: (1) higher levels of processing are not limited to preparing individual letters when familiar words are not available; (2) stored motor plans are available for frequently used bigrams. The second series of experiments addressed whether phonology affects within-word typewriting time-course. Participants typed letter strings designed to elicit resyllabification – the adjustment of syllable structure across a word boundary to aid speech articulation (see Levelt, Roelofs, & Meyer, 1999). For example, "bent inwards" is articulated with /tin/ as the second syllable. Participants typed word pairs in which consonant-vowel structure was manipulated across the word boundary such that if the words were articulated (including internally as inner speech) resyllabification would or would not occur. Latency of the consonant immediately before the word boundary in the resyllabification condition was shorter than in the control condition. Conversely, keystroke latencies after the word boundary were longer in the resyllabification condition. This is evidence of inner speech influencing the timing of motor production. The time-course of typewriting is influenced by sub-word processing units – production is facilitated for high-frequency letter combinations – but that motor processing after word output is not, contrary to some current theory, informationally encapsulated, but instead affected by concurrent, non-motor processing

Advances in Character Recognition

This book presents advances in character recognition, and it consists of 12 chapters that cover wide range of topics on different aspects of character recognition. Hopefully, this book will serve as a reference source for academic research, for professionals working in the character recognition field and for all interested in the subject

Apprentissage profond de formes manuscrites pour la reconnaissance et le repérage efficace de l'écriture dans les documents numérisés

Malgré les efforts importants de la communauté d’analyse de documents, définir une representation robuste pour les formes manuscrites demeure un défi de taille. Une telle representation ne peut pas être définie explicitement par un ensemble de règles, et doit plutôt être obtenue avec une extraction intelligente de caractéristiques de haut niveau à partir d’images de documents. Dans cette thèse, les modèles d’apprentissage profond sont investigués pour la representation automatique de formes manuscrites. Les représentations proposées par ces modèles sont utilisées pour définir un système de reconnaissance et de repérage de mots individuels dans les documents. Le choix de traiter les mots individuellement est motivé par le fait que n’importe quel texte peut être segmenté en un ensemble de mots séparés. Dans une première contribution, une représentation non supervisée profonde est proposée pour la tâche de repérage de mots manuscrits. Cette représentation se base sur l’algorithme de regroupement spherical k-means, qui est employé pour construire une hiérarchie de fonctions paramétriques encodant les images de documents. Les avantages de cette représentation sont multiples. Tout d’abord, elle est définie de manière non supervisée, ce qui évite la nécessité d’avoir des données annotées pour l’entraînement. Ensuite, elle se calcule rapidement et est de taille compacte, permettant ainsi de repérer des mots efficacement. Dans une deuxième contribution, un modèle de bout en bout est développé pour la reconnaissance de mots manuscrits. Ce modèle est composé d’un réseau de neurones convolutifs qui prend en entrée l’image d’un mot et produit en sortie une représentation du texte reconnu. Ce texte est représenté sous la forme d’un ensemble de sous-sequences bidirectionnelles de caractères formant une hiérarchie. Cette représentation se distingue des approches existantes dans la littérature et offre plusieurs avantages par rapport à celles-ci. Notamment, elle est binaire et a une taille fixe, ce qui la rend robuste à la taille du texte. Par ailleurs, elle capture la distribution des sous-séquences de caractères dans le corpus d’entraînement, et permet donc au modèle entraîné de transférer cette connaissance à de nouveaux mots contenant les memes sous-séquences. Dans une troisième et dernière contribution, un modèle de bout en bout est proposé pour résoudre simultanément les tâches de repérage et de reconnaissance. Ce modèle intègre conjointement les textes et les images de mots dans un seul espace vectoriel. Une image est projetée dans cet espace via un réseau de neurones convolutifs entraîné à détecter les différentes forms de caractères. De même, un mot est projeté dans cet espace via un réseau de neurones récurrents. Le modèle proposé est entraîné de manière à ce que l’image d’un mot et son texte soient projetés au même point. Dans l’espace vectoriel appris, les tâches de repérage et de reconnaissance peuvent être traitées efficacement comme un problème de recherche des plus proches voisins

On-line recognition of English and numerical characters.

by Cheung Wai-Hung Wellis.Thesis (M.Sc.)--Chinese University of Hong Kong, 1992.Includes bibliographical references (leaves 52-54).ACKNOWLEDGEMENTSABSTRACTChapter 1 --- INTRODUCTION --- p.1Chapter 1.1 --- CLASSIFICATION OF CHARACTER RECOGNITION --- p.1Chapter 1.2 --- HISTORICAL DEVELOPMENT --- p.3Chapter 1.3 --- RECOGNITION METHODOLOGY --- p.4Chapter 2 --- ORGANIZATION OF THIS REPORT --- p.7Chapter 3 --- DATA SAMPLING --- p.8Chapter 3.1 --- GENERAL CONSIDERATION --- p.8Chapter 3.2 --- IMPLEMENTATION --- p.9Chapter 4 --- PREPROCESSING --- p.10Chapter 4.1 --- GENERAL CONSIDERATION --- p.10Chapter 4.2 --- IMPLEMENTATION --- p.12Chapter 4.2.1 --- Stroke connection --- p.12Chapter 4.2.2 --- Rotation --- p.12Chapter 4.2.3 --- Scaling --- p.14Chapter 4.2.4 --- De-skewing --- p.15Chapter 5 --- STROKE SEGMENTATION --- p.17Chapter 5.1 --- CONSIDERATION --- p.17Chapter 5.2 --- IMPLEMENTATION --- p.20Chapter 6 --- LEARNING --- p.26Chapter 7 --- PROTOTYPE MANAGEMENT --- p.27Chapter 8 --- RECOGNITION --- p.29Chapter 8.1 --- CONSIDERATION --- p.29Chapter 8.1.1 --- Delayed Stroke Tagging --- p.29Chapter 8.1.2 --- Bi-gram --- p.29Chapter 8.1.3 --- Character Scoring --- p.30Chapter 8.1.4 --- Ligature Handling --- p.32Chapter 8.1.5 --- Word Scoring --- p.32Chapter 8.2 --- IMPLEMENTATION --- p.33Chapter 8.2.1 --- Simple Matching --- p.33Chapter 8.2.2 --- Best First Search Matching --- p.33Chapter 8.2.3 --- Multiple Track Method --- p.35Chapter 8.3 --- SYSTEM PERFORMANCE TUNING --- p.37Chapter 9 --- POST-PROCESSING --- p.38Chapter 9.1 --- PROBABILITY MODEL --- p.38Chapter 9.2 --- WORD DICTIONARY APPROACH --- p.39Chapter 10 --- SYSTEM IMPLEMENTATION AND PERFORMANCE --- p.41Chapter 11 --- DISCUSSION --- p.43Chapter 12 --- EPILOG --- p.47Chapter APPENDIX I - --- PROBLEMS ENCOUNTERED AND SUGGESTED ENHANCEMENTS ON THE SYSTEM --- p.48Chapter APPENDIX II - --- GLOSSARIES --- p.51REFERENCES --- p.5

Character Recognition

Character recognition is one of the pattern recognition technologies that are most widely used in practical applications. This book presents recent advances that are relevant to character recognition, from technical topics such as image processing, feature extraction or classification, to new applications including human-computer interfaces. The goal of this book is to provide a reference source for academic research and for professionals working in the character recognition field

Template Based Recognition of On-Line Handwriting

Software for recognition of handwriting has been available for several decades now and research on the subject have produced several different strategies for producing competitive recognition accuracies, especially in the case of isolated single characters. The problem of recognizing samples of handwriting with arbitrary connections between constituent characters (emph{unconstrained handwriting}) adds considerable complexity in form of the segmentation problem. In other words a recognition system, not constrained to the isolated single character case, needs to be able to recognize where in the sample one letter ends and another begins. In the research community and probably also in commercial systems the most common technique for recognizing unconstrained handwriting compromise Neural Networks for partial character matching along with Hidden Markov Modeling for combining partial results to string hypothesis. Neural Networks are often favored by the research community since the recognition functions are more or less automatically inferred from a training set of handwritten samples. From a commercial perspective a downside to this property is the lack of control, since there is no explicit information on the types of samples that can be correctly recognized by the system. In a template based system, each style of writing a particular character is explicitly modeled, and thus provides some intuition regarding the types of errors (confusions) that the system is prone to make. Most template based recognition methods today only work for the isolated single character recognition problem and extensions to unconstrained recognition is usually not straightforward. This thesis presents a step-by-step recipe for producing a template based recognition system which extends naturally to unconstrained handwriting recognition through simple graph techniques. A system based on this construction has been implemented and tested for the difficult case of unconstrained online Arabic handwriting recognition with good results