Composite Line Designs and Accuracy Measurements for Tactile Line Tracing on Touch Surfaces

Eyes-free operation of mobile devices is critical in situations where the visual channel is either unavailable or attention is needed elsewhere. In such situations, vibrotactile tracing along paths or lines can help users to navigate and identify symbols and shapes without visual information. In this paper, we investigated the applicability of different metrics that can measure the effectiveness of vibrotactile line tracing methods on touch screens. In two user studies, we compare trace Length Error, Area Error, and Fréchet Distance as alternatives to commonly used trace Time. Our results show that a lower Fréchet distance is correlated better with the comprehension of a line trace. Furthermore, we show that distinct feedback methods perform differently with varying geometric features in lines and propose a segmented line design for tactile line tracing studies. We believe the results will inform future designs of eyes-free operation techniques and studies.

The Frequency of Occurrence of Handwriting Performance Features Used to Predict Whether Questioned Signatures are Simulated

Forensic Document Examiners (FDEs) examine the physical morphology and performance attributes of a line trace when comparing questioned to specimen handwriting samples for the purpose of determining authorship. Along with spatial features, the elements of execution of the handwriting are thought to provide information as to whether or not a questioned sample is the product of a disguise or simulation process. Line features such as tremor, pen-lifts, blunt beginning and terminating strokes, indicators of relative speed, splicing and touch ups, are subjectively assessed and used in comparisons by FDEs and can contribute to the formation of an opinion as to the validity of a questioned sample of handwriting or signatures. In spite of the routine use of features such as these, there is little information available regarding the relative frequency of occurrence of these features in populations of disguised and simulated samples when compared to a large population of a single individual’s signature. This study describes a survey of the occurrence of these features in 46 disguised signatures, 620 simulated signatures (produced by 31 different amateur forgers) and 177 genuine signatures. It was found that the presence of splices and touch-ups were particularly good predictors of the simulation process and that all line quality parameters were potentially useful contributors in the determination of the authenticity of questioned signatures. Purchase Article - $10

Deburr Algorithm of Binary Image Based on Outline Trace

The paper introduces deburr algorithm before line trace in the course of vector quantization of binary map image, and it can receive better effect through applying for the algorithm.