Experimental analysis of Roman coin minting

Hartmann, Christoph; Hammerl, Franz; Volk, Wolfram

doi:10.1016/j.jasrep.2019.05.007

“…Recall that ancient Roman imperial coins were minted by striking a blank coin placed between hand-carved dies [23]. This is in contrast to casting, which was used briefly during the Republican period, as well as later in the production of medallions, probably due to their much larger size (often in excess of 50 g).…”

Section: Practical Applicationsmentioning

confidence: 99%

Images of Roman Imperial Denarii: A Curated Data Set for the Evaluation of Computer Vision Algorithms Applied to Ancient Numismatics, and an Overview of Challenges in the Field

Arandjelović¹,

Zachariou²

2020

Sci

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Automatic ancient Roman coin analysis only recently emerged as a topic of computer science research. Nevertheless, owing to its ever-increasing popularity, the field is already reaching a certain degree of maturity, as witnessed by a substantial publication output in the last decade. At the same time, it is becoming evident that research progress is being limited by a somewhat veering direction of effort and the lack of a coherent framework which facilitates the acquisition and dissemination of robust, repeatable, and rigorous evidence. Thus, in the present article, we seek to address several associated challenges. To start with, (i) we provide a first overview and discussion of different challenges in the field, some of which have been scarcely investigated to date, and others which have hitherto been unrecognized and unaddressed. Secondly, (ii) we introduce the first data set, carefully curated and collected for the purpose of facilitating methodological evaluation of algorithms and, specifically, the effects of coin preservation grades on the performance of automatic methods. Indeed, until now, only one published work at all recognized the need for this kind of analysis, which, to any numismatist, would be a trivially obvious fact. We also discuss a wide range of considerations which had to be taken into account in collecting this corpus, explain our decisions, and describe its content in detail. Briefly, the data set comprises 100 different coin issues, all with multiple examples in Fine, Very Fine, and Extremely Fine conditions, giving a total of over 650 different specimens. These correspond to 44 issuing authorities and span the time period of approximately 300 years (from 27 BC until 244 AD). In summary, the present article should be an invaluable resource to researchers in the field, and we encourage the community to adopt the collected corpus, freely available for research purposes, as a standard evaluation benchmark.

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“…Recall that ancient Roman imperial coins were minted by striking a blank coin placed between hand-carved dies [24]. This is in contrast to casting, which was used briefly during the Republican period, as well as later in the production of medallions, probably due to their much larger size (often in excess of 50 g).…”

Section: Practical Applicationsmentioning

confidence: 99%

Images of Roman Imperial Denarii: A Curated Data Set for the Evaluation of Computer Vision Algorithms Applied to Ancient Numismatics, and an Overview of Challenges in the Field

Arandjelović¹,

Zachariou²

2020

Sci

0

View full text Add to dashboard Cite

Automatic ancient Roman coin analysis only recently emerged as a topic of computer science research. Nevertheless, owing to its ever-increasing popularity, the field is already reaching a certain degree of maturity, as witnessed by a substantial publication output in the last decade. At the same time, it is becoming evident that research progress is being limited by a somewhat veering direction of effort and the lack of a coherent framework which facilitates the acquisition and dissemination of robust, repeatable, and rigorous evidence. Thus, in the present article, we seek to address several associated challenges. To start with, (i) we provide a first overview and discussion of different challenges in the field, some of which have been scarcely investigated to date, and others which have hitherto been unrecognized and unaddressed. Secondly, (ii) we introduce the first data set, carefully curated and collected for the purpose of facilitating methodological evaluation of algorithms and, specifically, the effects of coin preservation grades on the performance of automatic methods. Indeed, until now, only one published work at all recognized the need for this kind of analysis, which, to any numismatist, would be a trivially obvious fact. We also discuss a wide range of considerations which had to be taken into account in collecting this corpus, explain our decisions, and describe its content in detail. Briefly, the data set comprises 100 different coin issues, all with multiple examples in Fine, Very Fine, and Extremely Fine conditions, giving a total of over 650 different specimens. These correspond to 44 issuing authorities and span the time period of approximately 300 years (from 27 BC until 244 AD). In summary, the present article should be an invaluable resource to researchers in the field, and we encourage the community to adopt the collected corpus, freely available for research purposes, as a standard evaluation benchmark.

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“…The use of gold, silver (since 400 BC), copper, bronze and brass alloys to manufacture the Roman coins, for instance, is one of the pioneering mass production of metallic artefacts in history. The main minting processes were casting and plastic deformation; the latter could use hot or cold striking [9][10][11] . The metallographic analysis of two types of brass coins used by the Romans (Dupondius and AE) indicate the use of hot striking at temperatures above 800°C, see Figures 2a and 2b 10,11 .…”

Section: Introductionmentioning

confidence: 99%

“…The main minting processes were casting and plastic deformation; the latter could use hot or cold striking [9][10][11] . The metallographic analysis of two types of brass coins used by the Romans (Dupondius and AE) indicate the use of hot striking at temperatures above 800°C, see Figures 2a and 2b 10,11 . According to Calliari et al 12 , the Roman coinage process of Cu-base alloys between 100 and 300 AD could be divided into four steps: the production of alloys and casting; the blank manufacture; the hammering and annealing to produce the coin geometry; and the coin embossing by die striking.…”

Section: Introductionmentioning

confidence: 99%

History of the Recrystallisation of Metals: A Summary of Ideas and Findings until the 1950s

Azevedo

¹

,

Padilha

²

2020

Mat. Res.

2

0

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The paper reviews the events that led to the understanding of the recrystallisation of metals throughout history, covering the timeline from 3500 BC until the 1950s and dealing mainly with the misconceptions related to the "recrystallisation" and "amorphisation". This history begins with the thermomechanical processing of native metals in pre-Columbian America (3,000 BC), and the production of brass coins in Rome (100 BC). The analysis of the fracture surfaces of metals, commonly used between the 16 th and 18 th centuries in Europe for the quality control of metallic products, is briefly discussed. The observation of crystalline and fibrous fractures lead to the common misconception of the 19 th century that "recrystallisation" takes place during the heating of "amorphous" cold-worked metals. The use of reflecting optical microscopy in the late 19 th century indicated, however, that the plastic deformation only promotes a morphological change in the microstructure of the metals without any "amorphisation". In the early 20 th century, the plastic deformation of metals by crystal plane slipping and twinning was well documented by metallographic observation during tensile testing. Nevertheless, in 1915, Prof. Rosenhain advocated that the "crystal" inside the slip bands of a plastically deformed metal was "amorphous" and responsible for the work hardening. The discovery of the X-ray diffraction technique, in 1913, allowed to resolve the ongoing dispute of the "amorphisation" of metals during plastic deformation. Between the 1920s and 1950s, X-ray diffraction was practically the only means of studying the internal structure of metals to explain the nature of their plasticity, confirming many aspects of the dislocation theory. This technique was crucially important to understand the atomic crystal structure of metals in the annealed and cold-work states. Our history finishes in the 1950s when the transmission electron microscopy finally revealed the first images of dislocation in metals. Up to that date, most of the understanding of the dislocations' distribution and organisation in cold-work and annealed states had already been derived from X-ray diffractograms, which gave birth to the modern physical metallurgy.

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Experimental analysis of Roman coin minting

Cited by 5 publications

References 5 publications

Images of Roman Imperial Denarii: A Curated Data Set for the Evaluation of Computer Vision Algorithms Applied to Ancient Numismatics, and an Overview of Challenges in the Field

Images of Roman Imperial Denarii: A Curated Data Set for the Evaluation of Computer Vision Algorithms Applied to Ancient Numismatics, and an Overview of Challenges in the Field

Images of Roman Imperial Denarii: A Curated Data Set for the Evaluation of Computer Vision Algorithms Applied to Ancient Numismatics, and an Overview of Challenges in the Field

History of the Recrystallisation of Metals: A Summary of Ideas and Findings until the 1950s

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