Two-dimensional pin array displays enable access to tactile graphics that are important for the education of students with visual impairments. Due to their prohibitive cost and limited access, there is limited research within HCI and the rules to design graphics on these low-resolution tactile displays are unclear. In this paper, eight tactile readers with visual impairments qualitatively evaluate the implementation of Pixel Art to create tactile graphical primitives on a pin array display. Every pin of the pin array is assumed to be a pixel on a pixel grid. Our findings suggest that Pixel Art tactile graphics on a pin array are clear and comprehensible to tactile readers, positively confirming its use to design basic tactile shapes and line segments. The guidelines provide a consistent framework to create tactile media which implies that they can be used to downsize basic shapes for refreshable pin-array displays.

Tactile Graphics (TG) are raised line diagrams to represent pictorial content for People with Visual Impairments (PVI). While shapes may be simple to depict, objects often appear disjunctive when represented in graphics. Researchers have evaluated the efficacy of TG and stated factors like size, complexity, or prior visual experience, affecting identification. However, the specific features of a graphic or aspects that enable object (3D) recognition through them need investigation. We evaluate the interactions of 12 PVI (8 born-blind and 4 late-blind), having minimal experience with TG or graphical representations, with 20 tactile stimuli including daily objects. We present graphic- and process-based factors that aid recognition. Our results indicate unique elements or a combination leading to recognition. Born-blind participants were able to identify stimuli based solely on their prior tactile experience of the actual objects, the majority being depictions of objects with insignificant thickness. Mirroring hand movements for symmetrical shapes were observed. A broader classification followed by deduction appeared as a common strategy of exploration. These insights impart improved understanding and evaluation of tactile graphics.

The paper presents the dimensional design of a class of parallel manipulators, namely, Hexaslides. The design of hexaslides is formulated as a multiobjective optimization problem considering workspace and dexterity as dual objectives. As the relative emphasis on workspace and dexterity varies depending on the application, a set of Pareto-optimal solutions is found. The present analysis is a useful tool for designers to select suitable hexaslide parameters for a given application, particularly, in machine tool applications.