Everyone knows that ?a picture is worth a thousand words.? But did you know that it can also yield, oh, at least an hour or so of pleasant music?
The Library of Congress?s Preservation Directorate and a number of partners are essentially ?inventing? a new preservation technology that could revolutionize efforts to convert analog formats, such as LPs, to digitized versions of the recordings contained on the old media.
The process ? known as IRENE (Image, Reconstruct, Erase Noise, etc.) ? is rather ingenious.
Here?s how it works: First, IRENE (pictured, right) makes a high-resolution digital image of a disc record. The key is found in creating a digital audio file from the analog information in the disc?s grooves. IRENE can efficiently extract sound from an image of a fragile or damaged disc, ?heal? scratches or digitally ?reassemble? a broken phonograph record. The extracted sound is converted to standard digital files and stored for purposes of digital access and preservation.
Recent surveys of collections nationwide, such as the Heritage Health Index, have highlighted the acute need for large-scale preservation efforts. Millions of historical recordings are believed to be in need of preservation.
Haber says the process of converting a standard, two-dimensional disc can currently be achieve in ?near real-time.? The image resolution produces individual pixels that are roughly one micron wide. An entire ?raw? image file of a single disc can be 4 to 8 gigabytes, although that size shrinks to about 300 megabytes after processing.
Haber discussed plans to develop a second device ? called a ?Confocal Scanning Probe? ? for high-resolution, three-dimensional surface profiling of grooved media, such as wax cylinders. The separate process is required because three-dimensional media use an up-and-down stylus motion to produce sound, whereas flat discs employ side-to-side stylus movement. The best current technology can image a two- to four-minute wax cylinder in about 20 minutes, or roughly 10 times ?real time.?
Dianne van der Reyden, director for Preservation at the Library of Congress, said: ?This project represents a successful partnership between the Library and the scientific research community. The ability to capture sound from otherwise unplayable broken or damaged discs, and to do so in near real time, is remarkable. We look forward to working with LBNL on research and development for the next iteration to capture sound from similarly at-risk 3D audio media such as wax cylinders.?