# Multimedia Vision for the Visually Impaired through 2D Multiarray Braille Display
## 3 Proposed eBook Reader Application for 2D Braille Display
### Components and the Design of 2D Braille Display for the VI
#### 3.4.3 Braille Image Conversion on Braille Display for the VI
\begin{table}
\begin{tabular}{c c} \hline \hline
**Item** & **Recognition Characteristics** \\ \hline \multirow{3}{*}{Image details} & Expressing excessive detail can cause confusion in determining the direction and intersection of image outlines. Therefore, the outline in both low-and high-complexity images should be expressed as simply as possible to increase the information recognition capabilities. \\ \cline{2-3}  & \
\begin{tabular}{c} For an image containing a primary object, the background and surrounding data should be removed and only the outline of the primary object should be provided to increase recognition capabilities. \\ \end{tabular} \\ \cline{2-3}  &
\begin{tabular}{c} For an image without a primary object, such as a landscape, \\ translating the outline does not usually enable the VI to recognize \\ the essential information. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Survey results on tactile graphic recognition characteristics of the VI (15 blind, 10 with low vision) [19]. Figure 12: Steps in the conversion of a graphic image to braille cells: Row (**a**) translation of a graph (a low-complexity image); Row (**b**) translation of an illustration (a high-complexity image); Row (**c**) translation of a photograph (a high-complexity image); Column (**d**) results of quantization; Column (**e**) results of object detection; Column (**f**) results of first simplification; Column (**g**) results of second simplification; and Column (**h**) final output in the form of braille cells [19]. simplified contour image. Next, the corner points were extracted using the Shi-Tomasi algorithm [42]. Thus, the unnecessary corner points were removed to simplify the contour image. This simplification method increases the recognition rate of the central object. According to the survey (Table 4), expression of the tactile graphics must be simple, failing which the information might not be recognized by the VI users. Normally, since image sizes vary in most cases, a few of considerations, such as the size of the designated braille display and up/down scaling of the central object, must be taken into account. Moreover, while calculating the size and number of the cells, the vertical dots are twice as many as the horizontal dots (\(4\times 2\) dots). However, although we designed braille cells with eight dots, we tested them as six dots and considered the vertical dots as 1.5 times the horizontal dots (\(3\times 2\) dots). In addition, in this study, various braille display sizes have been considered for printing letters and figures: ranging from the small size of \(7\times 7\) cells to the current size of \(12\times 12\) cells, The braille display in this study was aimed to fit in the palm of a hand like a smartphone. Therefore, the \(12\times 12\) cell display was considered as the appropriate braille size involving a small keyboard. However, the resolution for the braille display is important for the VI in terms of image recognition. This can be easily understood through a comparison with the resolution of an image/video viewed by a non-disabled person: for example, it is like the difference between watching a soccer game in Standard Definition (SD) resolution and High Definition (HD) resolution. (An SD image has \(720\times 480\) -pixel resolution, which is expressed as 345.6 K pixels, whereas a HD image is expressed as 1049 K pixels.) The number of braille cells in the display device used in this study is \(12\times 12\) but, as shown in Figure 11, only \(11\times 11\) cells are used because the contents are expressed only on the contents' cells. Therefore, an image can be expressed with a total of 968 dots composed of 121 braille cells (eight dots per braille cell, and in the case of six dots, the number of dots equals 726). Because of this, braille cell resolutions and the image quality are proportional, but there is a trade-off with the recognition rate of the user, and the supplying price of the braille display. In this study, grounding of braille and fingers was considered.