June 24, 2020 0 By admin

Wikipedia: The Archimedes Palimpsest is a palimpsest (ancient overwritten manuscript) on parchment in the form of a codex (hand-written. The subject of this website is a manuscript of extraordinary importance to the history of science, the Archimedes Palimpsest. Who was Archimedes? Born: About BC in Syracuse, Sicily. At the time Syracuse was an independent. Greek city-state with a year history. Died or.

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The multispectral imaging of the Archimedes Palimpsest. The Palimpsest is a Byzantine codex palimpsezt the 10th century that contains partial texts of seven treatises. The Palimpsest also contains pages from other works, including, as we now know, two works by the Athenian orator Hyperides, who lived in the 4th century BCE.

The Archimedes Palimpsest is, then, a document of great cultural significance. The original Archimedes manuscript was a fairly large book, approximately 20 cm wide and 30 cm tall.

Byhowever, it was palimpsested; the book was broken, the text erased, and the bifolia cut in half along the folds. The translagion of the Archimedes manuscript, and that of several other codices, was reused to create a Euchologion.

The pages of the Euchologion measured approximately 15 cm wide and 20 cm tall. It was catalogued in by Papadopoulos-Kerameus, when it was in the metochion of the Holy Sepulchre in Istanbul.

Heiberg had photographs taken archimeces many pages archimexes the manuscript though not alland published his results in as the three volumes of Archimedes, Opera omnia. During the upheavals in Europe in the early 20th century, the manuscript disappeared from the metochion, and was seen publicly again only when a French family put the manuscript up for auction at Christie’s, New York, on October 28th, Many pages have been damaged by mold that did not exist inand four pages were deliber.

One leaf of the original treatise On spiral lines, oriented with the Archimedes text. The xrchimedes of the scholarly work on the manuscript are being published elsewhere; completely new editions of the Method and the Stomachion will result. Iron gall ink was used for both texts in the manuscript.

The ink of the later Euchologion is dark brown in color and the characters are quite readable on most of the pages. This difference in color appearance provides the basis for the imaging arcchimedes subsequent image processing. Imaging of the manuscript. palimosest

The Archimedes Palimpsest Project

Two teams were selected early in for preliminary experimental imaging of five detached leaves of the manuscript. One team, from the Chester F. Robert Johnston and Dr. Keith Knox, then of the Xerox Corporation, had collaborated with one of the authors for several years on the subject of imaging historical manuscripts, including the Dead Sea Scrolls.

The second imaging team was a group from Baltimore, MD headed by Dr. Initially in competition, these two teams have subsequently collaborated on the production of images for the scholars. Hope Mayo of Christie’s, who was working on the auction catalog.

While making inquiries of Christies’ staff in London about imaging technology, she happened to speak with Dr. Knox’s sister-in-law, who directed Dr. Mayo to the Rochester team. Scholars have long used ultraviolet lights to read palimpsests because the organic material in parchment “fluoresces,” meaning that the parchment absorbs the short-wavelength photons from the illumination and then re-emits.

The visible fluorescence is generated from within the parchment and thus “beneath” the inks. In multispectral imaging, digital images are collected of the same “scene” using light at a variety of wavelengths. The original goal was to “strip” away the later writings of the prayer book, leaving the original writings.

The first test images were collected during the summer of The bands of light to be imaged are selected by external “colored” filters. The images were processed and digitally stitched together via many custom and time-consuming computations to create processed images of the leaves.


The bands of wavelengths tranalation were imaged were selected by two types of optical filters: The center wavelengths of the bandpass filters were located at nm in the ultraviolet region of the spectrumnm blue lightnm greennm redand about nm near-infrared. The filters were carried in the filter “wheel” of palkmpsest SenSys camera between the lens and the sensor.

Three kinds of illumination were used: Thus a total of 15 spectral images were collected. The wavelength band transmitted by the lctf can be “tuned” electronically over a range of visible wavelengths from nm to nm; the passband is approximately 10 nm wide. Since the relative quantities of light from the two bands cannot be distinguished from the image, it was necessary to use an additional glass bandpass filter to “block” the longer wavelength.

Unfortunately, the use of glass filters in the optical path affected the images and complicated the subsequent processing.

Archimedes Palimpsest reveals insights centuries ahead of its time

Unavoidable small differences in the “tilts” of the filters relative to the sensor had the effect of translating the recorded images by small and varying distances. These translations had to be removed to “register” the images before performing the multispectral processing. The classes included “parchment”, “overwriting” from the Euchologion”underwriting” the desired original Archimedes textand mold on the page.

This palumpsest the algorithm to recognize the pattern of pixel brightness vs.

Because all mathematical computations are linear, the process often is called “linear pixel unmixing. Some examples of the resulting segmented images of Euchologion leaf 70v are shown in Figure 2. We were pleased with these results, as we felt they validated the proposed imaging and processing. When submitted to scholarly review by Dr. Reviel Netz of Stanford University and Dr.

Natalie Tchernetska of Cambridge University, the results were judged to have inadequate spatial resolution they were too “fuzzy” and that the image processing was not appropriate. The former condition had two sources: The original resolution was judged to be too coarse by a factor.

The image registration problem arose because pixels in images of the same location on the parchment taken at different wavelengths did not “line up” exactly, despite significant custom processing.

The resulting processed images are combinations of images taken at the different wavelengths and appear to be blurry. This problem could only be solved by a fundamental change in the image collection scheme. The second problem of inappropriate processing was due to the desire of the imagers to separate the Archimedes text from the overtext, i.

In a seeming paradox, this apparent success in fact made the Archimedes text more difficult for the scholars to read. The characters of the undertext exhibited “gaps” where they were obscured by the overtext, without any visible explanation for those gaps. The scholars needed to see both texts to identify the reason. In other words, the primary problem for transcription was the “faintness” of the original text, not the fact that it was overwritten.

The greatest single lesson that we have learned in the imaging of the Archimedes Palimpsest is that successful images are the product of interactive discussions between imagers and scholars. The worlds of the imager and of the scholar are very different; what appears trivial to one group may well be difficult for the other.

Based on intensive reviews of the results, we developed a new standard imaging protocol and processing algorithm. Image collection under this procedure began early in Since then, four imaging sessions have been held at the Museum at approximately six-month intervals.

More than two thirds of the book has been imaged using the simplified “standard” procedure; this phase of the imaging should be completed by the time this article is published. Image processing and display. Based on the results of the first phase, the imaging goal was modified to enhance the contrast of the original undertext while retaining visible overtext. We noted that the two texts could be segmented fairly well by using a simplified collection and processing algorithm that did not require supervised classification.


Because the Archimedes text is generally “redder” than the overwritten text, it is virtually invisible in the red channel of images taken under white-light illumination. In other words, the measured gray values of pixels that contain Archimedes text are approximately the same as those from the surrounding parchment when viewed in red light, so they cannot be distinguished. Because the color of the Euchologion text is much more neutral without color, i.

The visible-light and ultraviolet images were “split” into their respective three red, green, and blue color channels. This created three monochrome “black and white” images of the scene. Both texts appear to be rather “dark” in the blue channel of the ultraviolet-light image.

The red channel of the visible-light image Figure 3a and the blue. Simplified multispectral image processing, by balancing and subtraction f. The difference of these two “balanced” images resulted in the same gray values computed for pixels in both the parchment and Euchologion text; the Euchologion text “disappeared” into the parchment, as shown in Figure 3c. However, the subtraction step also enhances any noise present in the images and thus may interfere with the reading of the text.

Using this camera, we can easily obtain images with a spatial resolution of 25 pixels per mm dpi. The images are displayed using a simple method that conveys information from both texts to the reader simultaneously. The tungsten-red image with “bright” Archimedes text and “dark” Euchologion text is placed in the red channel, and the ultraviolet-blue image with both texts visible is inserted in the blue and green channels.

The resulting Archimedes text is “bright” in the red and “dark” in the green and blue, thus producing a “reddish” tint actually magentawhile the Euchologion text appears as a “neutral” gray.

This provides the reader with a color cue about the origin of the text.

Archimedes Palimpsest – Wikipedia

Each complete bifolium is imaged in ten overlapping sections. Images of the first section are collected, the translation table moves the manuscript to the next section, and the process is repeated.

After the images are collected generally at the end of each daythey are transferred from the PC control computer to a Unix workstation an Apple Powerbook laptop computer and are processed overnight to assess the quality of the imaging. After the entire imaging session is completed, the processed image sections are digitally “stitched” together to form large images of the complete bifo. Commercial software packages are used for stitching, from RealViz, Inc. Results are shown in Figure 4.

The scholars find these pseudocolor images to be generally easier to read than the manuscript itself. Use of images by scholars. Nigel Wilson of Lincoln College, Oxford, individually analyze the processed images to read the original text. Three color images of each bifolium are sent to each scholar; those taken under xenon strobe illumination and ultraviolet light, plus the result of the pseudocolor image processing.

The original plan was to distribute the processed images as printed copies on paper and as electronic images on cd-rom.

Particularly for the electronic copies, this rapidly became impractical due to the large volume of data.