Design Maintainability of Communication Written in Braille Code ^†

Abstract

Human information processing is often considered vision-dominant. However, perception is multisensory and shaped by interactions among sensory modalities as well as by top-down processes that integrate prior knowledge and context. Research demonstrates that these mechanisms influence early neural processing and enrich perception beyond purely bottom-up input. For individuals who are blind, this adaptability allows for the effective acquisition of information through alternative sensory channels, provided that accessibility systems are in place. A central challenge is the limited access to written materials, including text, numerical data, and music notation. Assistive technologies such as speech synthesis and Braille have become key solutions. This contribution focuses on Braille, discussing issues of organization, standardization, and technical design. It also introduces the project “Braille Display Screen Based on Long-Wave Infrared Radiation,” which seeks to create a passive Braille display as an alternative to conventional actuator-based devices.

1. Introduction

Information processing in humans is frequently ascribed to vision. Such assessments are not entirely precise, given the overlap of sensory modalities and the enrichment of perception through prior knowledge. Humans rely predominantly on vision for information processing, with estimates suggesting that approximately 80% of sensory input in daily life is visual [1,2,3], which explains why information flow is often primarily attributed to vision. However, perception is not confined to a single modality. Rather, it is shaped by multisensory integration, where vision, hearing, touch, smell, and taste overlap and influence one another. Classic demonstrations such as the McGurk effect [4] illustrate how auditory and visual signals can interact to alter perception, while visual cues can also modulate the way food is experienced through taste. In addition, information processing is not exclusively bottom-up. The brain continuously integrates sensory data with prior knowledge, expectations, and contextual cues in a process known as top-down processing [5,6]. This interaction enriches perception but also introduces potential biases, as our interpretations of sensory input are shaped by what we already know or believe. In [5], participants were given degraded visual input of objects, preceded by a congruent or incongruent name which served as prior knowledge. It was found that when the name was congruent, objects were recognized earlier, and changes in brain activity occurred not only in higher-level cortical areas but also in early visual processing areas. This shows that prior knowledge can modulate perception by influencing the processing of sensory input. The [6] study manipulated prior knowledge by showing a written text before listening to degraded spoken words. When the text matched, the clarity of perception was enhanced. Also, the effect of knowledge preceded certain neural activations, indicating feedback influence from higher to lower processing areas, rather than purely bottom-up input. Therefore, individuals who are blind are capable of effectively acquiring information via alternative sensory channels, underscoring the necessity of adapting systems for information accessibility.

One of the principal challenges faced by the blind population is access to written materials, encompassing textual content, numerical data, and even musical notation. The availability of such materials is facilitated through the application of assistive technologies, with speech synthesis and Braille constituting the most prominent modalities. This contribution is focused on the latter. The effectiveness of these systems depends on the adequate organization, standardization, and systematic maintenance of the materials. These factors pose technical challenges with direct implications for the design and functionality of assistive solutions. Furthermore, this contribution examines the methods by which access to written content is secured for individuals who are blind, with particular emphasis on the technical aspects of Braille material. A brief history of assistive systems is presented because similar design challenges, mainly concerning non-user-oriented design, are often embedded into contemporary technical solutions due to the fact that designers themselves are not blind. The authors faced such challenges in the first stage of the project “Braille Display Screen Based on Long-Wave Infrared Radiation” (NPOO.C3.2.R3-I1.05.0191) that aims to develop a display of passive elements arranged in a six-point Braille grid, unlike conventional solutions that rely on actuators [7].

2. Design Limitations of Early Technical Solutions

Early attempts to make written content accessible to the blind faced several design issues. Haüy’s relief letters [8,9] were bulky, wore down quickly, and were difficult to write, limiting use mostly to institutions. Klein’s dotted Latin letters [10] were more durable but still complex to write and too intricate for quick tactile reading. Moon’s simplified embossed letters were easier to read but again bulky, taking up more space than Braille’s [8]. Barbier’s dot system [8] improved durability and ease of writing, but the letter cells were too large, some contained too many dots, and the system had too few practical characters. Braille’s first version [9,10] addressed many of these issues but introduced horizontal lines, which were harder to distinguish from dots and more difficult to write, making it a ternary system that was less efficient than a purely dot-based code. Overall, the main design challenges were balancing readability, ease of writing, durability, and an optimal number of characters for practical use.

From an inventor-centered perspective, the most intuitive approach to making written content accessible to blind users was to render standard ink-based characters in relief. Such adaptations did not employ specialized scripts for the blind. The visual script used by sighted individuals was mechanically reproduced in raised form and often simplified. For example, only capital letters in sizes conducive to tactile perception were commonly employed. Multiple attempts at this approach were undertaken.

Valentin Haüy developed wooden letters for instructional purposes and, more notably, relief letters embossed into paper. Letters fabricated from copper wire were pressed into damp paper, producing raised lines that could be bound into books. Haüy’s method exhibited significant practical limitations: the resulting books were heavy, and the relief characters wore down quickly, reducing legibility. Additionally, producing these embossed letters required specialized skills and equipment, limiting usage primarily to institutional settings.

• Johann Wilhelm Klein introduced a technique for producing Latin letters using dotted instead of solid lines. This involved a dense array of raised points arranged to approximate standard character shapes. While this method improved durability and facilitated recording, the complexity of writing symbols and the relative difficulty of rapid tactile reading hindered practical adoption.
• William Moon devised a simplified embossed Latin script characterized by basic geometric shapes for individual letters. These modifications were designed to enhance tactile readability. Moon’s system retained a significant spatial footprint compared to other methods and required additional shorthand adaptations to reduce volume. Despite some practical advantages, the approach ultimately did not achieve widespread adoption.
• The principle of embossing printed characters for tactile reading also underpinned the optical-to-tactile converter (Optacon) [11] (op, pp), an electromechanical device converting printed text on paper or displays into raised, tactile patterns using small vibrating pins. This is probably the first system that resembles what would be a modern technical solution. The Optacon included a camera mounted on a guide traversed over the text and a small tactile display read by touch. Although the device enabled independent reading of standard print by blind users, its operational constraints, such as high cost, slow reading speed, and user fatigue due to pin vibration, limited broader adoption.

The mentioned technical solutions illustrate a recurring design challenge, which is that solutions appearing most intuitive from an inventor’s perspective are not necessarily optimal for end users. Critical issues include balancing durability, spatial efficiency, ease of recording, and tactile legibility. Systems tended to be either too complex for independent writing or physically challenging for practical reading, demonstrating the trade-offs inherent in early tactile writing technologies.

3. The Braille Code

3.1. Dot and Line System

In the first version of the Braille system, each character cell had 6 positions arranged in 2 columns of 3, allowing up to 6 dots. Characters could include both dots and horizontal lines, with lines replacing pairs of horizontally adjacent dots. This system could theoretically produce 125 different characters, including the space, though only 90 were initially assigned values. The first 4 sets of 10 characters consisted only of dots and corresponded roughly to modern letters. Subsequent sets were used for digits, punctuation, mathematical symbols, musical notation, and auxiliary signs.

Braille’s first system had certain limitations. Horizontal lines were difficult to distinguish from dots at higher reading speeds, and writing both dots and lines was more complex than writing only dots. It functioned as a ternary code, which is less efficient than simpler binary systems.

The second, modern version of Braille improved on these issues. Characters consist exclusively of dots, arranged in the same six-position cell, optimizing them for tactile recognition by the fingertip. Limiting characters to dots simplified both writing and reading, whether using a stylus and slate or Braille typewriter. The dot patterns allow readers to perceive the character as a single shape rather than focusing on individual dots, enabling faster reading. The system also accommodates a relatively large number of characters, with ambiguity resolved through multi-character combinations.

3.2. 6-Digit Binary System

What is now referred to as Braille script is a six-digit binary code, in which a raised dot represents a 1, and the absence of a dot represents a 0. Braille characters encode letters, numbers, musical notes, various auxiliary symbols (punctuation, mathematical signs, musical notation symbols), as well as abbreviations, symbols, and more. In this sense, Braille, although usually considered a writing system, is not a typical script, because scripts are usually limited to written words and, in some cases, specific numeric notation. Braille is a tactile code.

Braille code has $2^6$ single-cell characters, including the space. These characters, in the above-mentioned, second version of Braille, are organized into sequences. There are 6 sequences of 10 characters each, and 1 sequence of 4 characters. The corresponding system of sequences essentially applies to all Braille system, i.e., languages. These are the systems predominantly used by the blind in Europe and America. The dots in a Braille cell are arranged in 2 columns of 3 dots each, counted from top to bottom first in the left column (1, 2, 3) and then in the right column (4, 5, 6). Table 1 summarizes the Braille system of sequences.

Table 1. Sequences in Braille 6-digit binary code.

Sequence	Dot Pattern (s)	Letters/Numbers/Notes	Explanation
1st	1, 12, 14, 145, 15, 124, 1245, 125, 24, 245	a–j	Letters also represent numbers 1–0 when preceded by the number sign(3456); Letters d–j also indicate eighth notes
2nd	13, 123, 134, 1345, 135, 1234, 12345, 1235, 234, 2345	k–t	Letters n–t also indicate half notes
3rd	136, 1236, 1346, 13456, 1356, 12346, 123456, 12356, 2346, 23456	u, v, x, y, z, five French letters with diacritics	Letters y–last also indicate whole notes C–H
4th	16, 126, 146, 1456, 156, 1246, 12456, 1256, 246, 2456	Letters with diacritics, digraphs, w	Characters 4–10 also indicate quarter notes
5th	2, 23, 25, 256, 26, 235, 2356, 236, 35, 356	Punctuation, auxiliary symbols	Can indicate exponents, musical measures, context-dependent
6th	4, 45, 34, 345, 346, 3456, 46, 456, 5, 56	Punctuation, auxiliary symbols, letters in some languages	Dot manipulations mirror previous sequences
7th	3, 36, 6, 0	Remaining symbols	Includes number 0 (346 in 6th sequence for clarity)

More unusual Braille systems assign values differently. In Algerian Braille, for example, cells are assigned according to the Arabic alphabet, not the traditional Braille sequence.

The limited number of Braille cells is addressed in two ways. Firstly, a single cell can represent multiple meanings depending on context. For example, 36 can indicate either a hyphen or a dash, as these symbols rarely appear in the same context. A cell can represent a letter, number, or musical note, with context determining its meaning. Special symbols like the number sign or word sign clarify meaning when context alone is insufficient. Secondly, some characters combine multiple cells to represent a single printed symbol. Formatting is done as follows: A capital letter sign precedes the letter to capitalize it; for multiple letters, a continuous capital sign applies; and italics (code 456) and bold (code is double 456) also precede the text. These formatting conventions cannot convey font type, size, or color, and repeated signs may be visually distracting. Single cells can also substitute for multiple printed characters. In addition, many languages use fixed contractions. For instance, in German Braille “au” is 16, “äu” is 34, “ei” is 146, “eu” is 126, “ie” is 346, “ch” is 1456, and “sch” is 156.

As Braille text occupies substantial space, shorthand systems with contractions are common. German Braille shorthand is particularly systematic, covering phonemes, prefixes, suffixes, and entire words, thus saving 30 to 40% of space. For example, code 12345 surrounded by spaces represents “voll.”

Attempts were made to expand Braille with 2 additional dots, creating an eight-dot system with 256 possible characters. This system was used in Spain, while Austria and West Germany experimented with eight-dot Braille for stenography. Today, eight-dot Braille mainly appears in digital devices to convert printed text into Braille. While easier to encode character-by-character, it is more difficult to read than six-dot Braille. That said, modern computers can convert text into classical Braille efficiently, reducing the practical need for eight-dot systems.

3.3. Challenges of Reading Braille

The challenges of reading Braille include its steep learning curve, the need for strong tactile sensitivity, slower reading speed, limited availability of materials, bulkiness of Braille texts, high cost and barriers of technology, and social factors such as limited teaching and stigma. Reading Braille is an empowering way for people who are blind or have low vision to access information, but learning the code can be difficult, as it has its own alphabet, contractions, and shorthand rules that require time and practice to master, especially for adults who lose vision later in life. Successful reading also depends on strong tactile sensitivity, which can be reduced by age or health conditions such as diabetes, making it harder to distinguish the raised dots. Even for fluent readers, Braille is usually slower than reading print, and materials are not always widely available, since producing Braille books is costly and often results in bulky volumes. While digital Braille displays help with portability, they are expensive and not always compatible with all technology. Finally, limited teaching in schools and social stigma around using Braille can further reduce opportunities for learning and use.

Therefore, a new research initiative at the Faculty of Electrical Engineering, Computer Science and Information Technology Osijek is exploring the development of a Braille display based on long-wave infrared radiation within the project “Braille Display Screen Based on Long-Wave Infrared Radiation” (NPOO.C3.2.R3-I1.05.0191). Unlike conventional solutions that rely on actuators, this approach proposes the use of passive elements arranged in a six-dot Braille grid. Such a system could lower resource requirements, reduce investment costs, and create new opportunities for expanding the use of Braille.

However, preliminary studies revealed challenges related to the perception of warmth. Two main factors seem to limit readability [7]. The fingertips are not highly sensitive to small temperature variations detected in the prototype, and the human sensory response to temperature changes is relatively slow and cannot register the rapid sequence of subtle variations (around ten per second) that the tactile system normally processes when reading Braille.

4. Discussion

Although vision dominates human information processing, accounting for the majority of sensory input, perception is inherently multisensory and influenced by prior knowledge. Research demonstrates that auditory, visual, and linguistic cues can significantly alter sensory experiences, while top-down processes enrich but also bias perception. For individuals who are blind, this adaptability allows for the efficient use of alternative modalities such as touch and hearing. However, access to written materials remains a major challenge, making assistive technologies essential. Among these, Braille has been central, yet its use is limited by several factors. Learning Braille requires time and high tactile sensitivity, and even skilled readers generally achieve slower speeds than those reading print. Production of Braille texts is costly and results in bulky volumes, while digital Braille displays, though more practical, remain expensive and sometimes technologically restrictive. These challenges highlight the need for innovative solutions. Current research at the Faculty of Electrical Engineering, Computer Science and Information Technology Osijek explores a novel Braille display that employs passive elements activated by long-wave infrared radiation. While promising, early results revealed perceptual constraints related to warmth sensitivity and response time of the user.