To determine the optimum size of a braille font, we conducted an experiment in which a popular Japanese braille font was printed at various sizes on capsule paper and read and rated by late blind people. The results show that braille printed at 16 to 19-point sizes was read faster and rated higher than that printed at smaller or larger sizes. These optimum sizes mostly coincide with those found for young congenitally blind people. A new finding was that many reading errors that stemmed from mistaking the range of braille cells were observed at larger sizes, 20 to 22-point sizes. This means that enlarging the font size is not necessarily beneficial for late blind people and optimum sizes should be strictly selected when doing so.

View full abstract

Because of rapid population aging, it is necessary to design interfaces that can decrease cognitive workload. The design implications and evaluation criteria for creating such senior-friendly or disability-friendly interfaces need to be established. One element related to memory function that can be manipulated in an interface is visuospatial working memory. However, there are few reports regarding the relationship between visuospatial working memory volume and age. In this paper, we aim to clarify how visuospatial working memory volume changes across the lifespan. We implemented a gamified application named VisuoSpats, which is based on the visual pattern span test, to measure visuospatial memory. The introduced gamification elements included points, leaderboards, and feedbacks. Three hundred and sixty-nine individuals aged 2 to 92 years old participated in this study. The results indicate that the median number of cells memorized was 7.0 (interquartile range: 5.0-9.0) across all age groups. Moreover, the number of cells memorized tends to increase as age increases until the age range of 21-25 years, and then decreases gradually with increasing age. Based on the comments by teenagers or seniors, the effective gamification elements of VisuoSpats could be competition elements such as points and ranking, or diagnostic factors, respectively.

View full abstract

Braille contents can be presented to a visually impaired person not only by dots on embossed paper but also dynamically by machine. The material of the parts of these Braille display tools that are touched by fingers has an effect on comfort in reading Braille. The effect seems to be due mainly to the friction change caused by perspiration. In this research we experimentally examined how sweat affects the friction between a finger and an object. Comparing acrylic sheet and copy paper, we found the influence of sweat to be greater on acrylic sheet and that even a sweating fingertip did not show a change in frictional force when rubbing an object covered with copy paper.

View full abstract

In this paper, we propose a stand-alone mobile visual search system based on binary features and the bag-of-visual words framework. The contribution of this study is three-fold: (1) We propose an adaptive substring extraction method that adaptively extracts informative bits from the original binary vector and stores them in the inverted index. These substrings are used to refine visual word-based matching. (2) A modified local NBNN scoring method is proposed in the context of image retrieval, which considers the density of binary features in scoring each feature matching. (3) In order to suppress false positives, we introduce a convexity check step that imposes a convexity constraint on the configuration of a transformed reference image. The proposed system improves retrieval accuracy by 11% compared with a conventional method without increasing the database size. Furthermore, our system with the convexity check does not lead to false positive results.

View full abstract