The aim of this work is to bring the cultural heritage of two-dimensional art closer to being accessible by blind and visually impaired people.
Our galleries are full of wonderful paintings – some so famous that nearly everyone knows about them. Unfortunately, blind and visually impaired people are mostly excluded from the world of visual arts. Some museums offer special guided tours describing selected paintings verbally. However, it is extremely difficult to crate a mental image from acoustic impressions only. State of the art tactile diagrams (a stylized version of the painting, mostly line drawings embossed on paper) help getting an overview, but allow only a very simplified view. On the other side, hand-crafted bas reliefs are very detailed and good to read, but require skilled sculptors in the fully manual creation process. We wanted to create a process that doesn't require any manual skills, and allows the creation of different tactile representations of suitable complexity, while being faithful to the original artworks.
The focus of the project is to help the artist as much as possible in the transfer process by finding appropriate computer-aided techniques, and to ease the production by utilizing rapid prototyping devices. At the current stage of the project, we developed a computer-assisted process, that converts images into three different tactile media of increasing complexity. This process consists of three consecutive stages. At the end of each stage, the data for the production of one tactile media is available.
In the first stage, important structures are identified, resulting in line drawings that separates the images into semantically meaningful entities. These drawings, vectorized and augmented with different fill patterns can be used to produce tactile diagrams.
The second stage adds in depth that is an important part in most figurative paintings. The human eye is trained in decoding this hidden third dimension, while the tactile sense is used to getting three-dimensional input directly. A custom built, intuitive user interface allows the artist to quickly annotate depth relations, and the software automatically assigns an appropriate depth to each object in the painting. The resulting discrete depth map is converted into layers to be laser-cut out of flexible plastic sheets and assembled on top of each other to form a "layered depth diagram".
In the third stage, texture information is extracted from the original paintings using customizable filter stages (similar to processing stages in the human eye) and superimposed on the layered depth diagrams. With an interactive, three-dimensional preview software, the filter settings can be optimized, perspective effects can be enabled, and correction-layers from external software can be mixed in. The resulting "textured reliefs" can be manufactured with computer-controlled CNC milling machines. It takes several hours, until the fine milling tools carve out all the fine detail. Custom software to create the machine codes had to be developed, since no commercial CAM software was able to process this highly detailed data. From a negative cast, mutliple copies can be mold. Several materials have been tested, until a durable, stain-resistant and pleasant material was found.
The project was performed in cooperation with Kunsthistorisches Museum Vienna and was funded by "KulturKontakt Austria im Auftrag des BMUKK". Four textured reliefs for three paintings with accompanying descriptions in braille are currently available, and special guided tours are offered.