Melvin Wevers’s research while affiliated with University of Amsterdam and other places

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Publications (17)


Autochromes and photochromes of the Orient and Occident
The histogram on the bottom shows the 16 dominant colors and their relative frequency.
SHAP plot for autochrome vs photochrome classifier (16 colors, 512 buckets), demonstrating the impact of various color features
Each row corresponds to a feature, represented by a number that indicates the color bucket. The x-axis shows the SHAP value (impact on model output), while the color gradient from blue to red represents low to high feature values within each bucket. The color swatches display the central RGB values (color) for the top five most influential color buckets.
SHAP plot for Occident vs Orient classifier in photochromes (16 colors, 512 buckets)
See Fig. 2 for a detailed explanation.
Coloring in the world of others: color use in visual orientalism, 1890–1920
  • Article
  • Full-text available

October 2024

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50 Reads

Humanities and Social Sciences Communications

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Melvin Wevers

This study investigates the impact of media on color sense: our ability to see different colors and use them to interpret the world. Specifically, we examine the role of color in the cultural construction of the Orient—an ‘imagined geography’ used to justify colonial domination—in two turn-of-the-twentieth-century types of color(ed) photographs: photochromes, where a printer added color, and autochromes, where colors were captured during exposure. While most research on visual Orientalism has focused on content, we use machine learning methods to study the most important formal element of visual Orientalism: color. After using K-means clustering to extract sixteen dominant colors from each photograph in our dataset, we train three different random forest classification algorithms to make a distinction between (A) the two color media (B) photochromes of the Orient and the Occident; and (C) autochromes of the Orient and the Occident. Subsequently, we apply Shapley Additive Explanations, an explainable AI method, to interpret the output of the classifiers. This allows us to examine how specific features (colors) impacted the classifiers’ predictions. While the algorithm can easily separate photochromes from autochromes (0.95) and Oriental from Occidental photochromes (0.93), it struggles with the same task in the autochrome collection (0.68). These findings support three interconnected conclusions: (1) color sense became mediated in the late nineteenth century, (2) in photochromes, the presence and absence of specific colors was a vital aspect of visual Orientalism, (3) the autochrome, where color was derived from light, provided a more objective picture of countries in the near and middle East than the photochrome.

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A multimodal turn in Digital Humanities. Using contrastive machine learning models to explore, enrich, and analyze digital visual historical collections

March 2023

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236 Reads

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20 Citations

Digital Scholarship in the Humanities

Until recently, most research in the Digital Humanities (DH) was monomodal, meaning that the object of analysis was either textual or visual. Seeking to integrate multimodality theory into the DH, this article demonstrates that recently developed multimodal deep learning models, such as Contrastive Language Image Pre-training (CLIP), offer new possibilities to explore and analyze image–text combinations at scale. These models, which are trained on image and text pairs, can be applied to a wide range of text-to-image, image-to-image, and image-to-text prediction tasks. Moreover, multimodal models show high accuracy in zero-shot classification, i.e. predicting unseen categories across heterogeneous datasets. Based on three exploratory case studies, we argue that this zero-shot capability opens up the way for a multimodal turn in DH research. Moreover, multimodal models allow scholars to move past the artificial separation of text and images that was dominant in the field and analyze multimodal meaning at scale. However, we also need to be aware of the specific (historical) bias of multimodal deep learning that stems from biases in the training data used to train these models.


Fig. 1: Classified adverts from De Tijd (19 January, 1957) Copyright: De Tijd.
Fig. 5: Clustering of advertisements based on width, height, and relative position in Trouw. (a) Even pages (b) Odd pages.
Fig. 5 (continued)
Fig. 7: Advertisements for Buffalo cigarettes in Limburger Koerier, April 13, 1938.
Fig. 10: Top 50 Bursty Nouns and Adjectives in Cigarette advertisements, 1890-1990.
Mining Historical Advertisements in Digitised Newspapers

December 2022

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97 Reads

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2 Citations

Historians have turned their focus to newspaper articles as a proxy of public discourse, while advertisements remain an understudied source of digitized information. This paper shows how historians can use computational methods to work with extensive collections of advertisements. Firstly, this chapter analyzes metadata to better understand the different types of advertisements, which come in a wide range of shapes and sizes. Information on the size and position of advertisements can be used to construct particular subsets of advertisements. Secondly, this chapter describes how textual information can be extracted from historical advertisements, which can subsequently be used for a historical analysis of trends and particularities. For this purpose, we present a case study based on cigarette advertisements.


Computer Vision for the Humanities: An Introduction to Deep Learning for Image Classification (Part 1)

August 2022

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52 Reads

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1 Citation

The Programming Historian

This is the first of a two-part lesson introducing deep learning based computer vision methods for humanities research. Using a dataset of historical newspaper advertisements and the fastai Python library, the lesson walks through the pipeline of training a computer vision model to perform image classification.


Computer Vision for the Humanities: An Introduction to Deep Learning for Image Classification (Part 2)

August 2022

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20 Reads

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1 Citation

The Programming Historian

This is the second of a two-part lesson introducing deep learning based computer vision methods for humanities research. This lesson digs deeper into the details of training a deep learning based computer vision model. It covers some challenges one may face due to the training data used and the importance of choosing an appropriate metric for your model. It presents some methods for evaluating the performance of a model.




Figure 1: Frontpage of Algemeen Handelsblad on July 21, 1969
Figure 5: Distance per newspaper to average time series for a random set of 1,000 dates. Mean-aggregated by decade with CI at 95%.
Figure 7: Clustering dendrogram (top) with per-cluster archetypical time series (bottom). DBA time series are indicated by bold lines. Underlying event flows used for the calculation are shown in thin lines. Selected events, window size of 28.
Overview of newspapers in dataset
Event Flow -- How Events Shaped the Flow of the News, 1950-1995

September 2021

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84 Reads

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1 Citation

This article relies on information-theoretic measures to examine how events impacted the news for the period 1950-1995. Moreover, we present a method for event characterization in (unstructured) textual sources, offering a taxonomy of events based on the different ways they impacted the flow of news information. The results give us a better understanding of the relationship between events and their impact on news sources with varying ideological backgrounds.


Figure 2. Error rates of the winning entries on the ImageNet Large Scale Visual Recognition Challenge from 2010 to 2017 (based on Russakovsky et al., 2015, and http://image-net.org/challenges).
Overview of the six most commonly used benchmark computer vision datasets (2004-2018) (based on Everingham et al., 2010; Fei-Fei et al., 2004; Griffin et al., 2007; Kuznetsova et al., 2018; Lin et al., 2014; Russakovsky et al., 2015). Citations from Google Scholar (4 December 2020).
The agency of computer vision models as optical instruments

March 2021

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691 Reads

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18 Citations

Visual Communication

Industry and governments have deployed computer vision models to make high-stake decisions in society. While they are often presented as neutral and objective, scholars have recognized that bias in these models might lead to the reproduction of racial, social, cultural and economic inequity. A growing body of work situates the provenance of bias in the collection and annotation of datasets that are needed to train computer vision models. This article moves from studying bias in computer vision models to the agency that is commonly attributed to them: the fact that they are universally seen as being able to make biased decisions. Building on the work of Bruno Latour and Jonathan Crary, the authors discuss computer vision models as agential optical instruments in the production of contemporary visuality. They analyse five interconnected research steps – task selection, category selection, data collection, data labelling and evaluation – of six widely cited benchmark datasets, published during a critical stage in the development of the field (2004–2020): Caltech 101, Caltech 256, PASCAL VOC, ImageNet, MS COCO and Google Open Images. They found that, despite all sorts of justifications, the selection of categories is not based on any general notion of visuality, but depends heavily upon perceived practical applications, the availability of downloadable images and, in conjunction with data collection, favours categories that can be unambiguously described by text. Second, the reliance on Flickr for data collection introduces a temporal bias in computer vision datasets. Third, by comparing aggregate accuracy rates and ‘human’ performance, the dataset papers introduce a false dichotomy between the agency of computer vision models and human observers. In general, the authors argue that the agency of datasets is produced by obscuring the power and subjective choices of its creators and the countless hours of highly disciplined labour of crowd workers.


Citations (10)


... SA is a process that employs NLP, text analysis, and computational linguistics to derive subjective information from textual data [14]. The field has grown significantly due to the widespread presence of usergenerated content on social media and review sites [15]. The main goal of SA is to identify the sentiment polarity as POS, NEG, or neutral, using various ML and Lexicon Based (LB) techniques [16]. ...

Reference:

Enhancing Sentiment Analysis and Rating Prediction Using the Review Text Granularity (RTG) Model
Quantitative text analysis
  • Citing Article
  • April 2024

Nature Reviews Methods Primers

... The method proposed in Figure 5 could also be used to analyse how semiotic modes such as text-flow and page-flow, which are regularly deployed in combination with diagrams in various media, use layout as an expressive resource (Bateman, 2008: 176). Similar methods are currently being developed for large-scale analysis of historical newspapers in the field of digital humanities (Wevers, 2023). ...

Mining Historical Advertisements in Digitised Newspapers

... In recent years, the digitization of historical archives has opened up new possibilities for analyzing and understanding our past through visual records [29]. Photographs, in particular, offer rich insights into historical events, cultural practices, and societal changes. ...

What to do with 2.000.000 Historical Press Photos? The Challenges and Opportunities of Applying a Scene Detection Algorithm to a Digitised Press Photo Collection

TMG Journal for Media History

... Similar interaction patterns between novelty and resonance have been successfully employed to study the manner in which online news media responded to catastrophic events [8,9,10]. In [11], the same fundamental method of analysis demonstrates that novelty-resonance patterns clearly track major social and historical events in the 20th century, using data taken from the front page of Dutch newspapers. ...

Event Flow -- How Events Shaped the Flow of the News, 1950-1995

... ai will destroy/save humanity. In short, we are witnessing a reversal of Latour's (1987) earlier observation of the limited agency attributed by humans to instruments and machines with ai models frequently attributed extreme or even super-human levels of agency (Smits and Wevers, 2022). ...

The agency of computer vision models as optical instruments

Visual Communication

... In this space, the relative positions of different words reflect their semantic relationships, with words that have similar meanings being represented by vectors that are closer together in the multidimensional space. This approach of ours aligns itself with similar uses of word embeddings to study political change within recent research in conceptual history (Wevers & Koolen 2020;Verheul et al. 2022) some of which also includes terrorism as part of their study objects (Marjanen et al. 2018;Lorella & Verheul 2020;Eijnatten & Ihalainen 2022). ...

Digital begriffsgeschichte: Tracing semantic change using word embeddings

Historical Methods A Journal of Quantitative and Interdisciplinary History

... The inclusion of multilingual metadata compounds these difficulties, as users may search in one language while content is cataloged in another. (4) This paper investigates the challenges and potential improvements related to keyword-based search within digital archives curated by GLAM institutions. It underscores the urgent need for more advanced retrieval techniques that surpass simple keyword matching. ...

The visual digital turn: Using neural networks to study historical images

Digital Scholarship in the Humanities

... However, OCR struggles with noisy document images. 44,45 In Ref. 44, for example, lexicons were used to classify recipes in digitized historical newspapers, and the performance of the classifier dropped because those relatively clean lexicons could not address or cover the various distortions in the digital texts caused by noise. Similarly, Lansdall-Welfare et al. 45 sought to identify and extract words to classify and represent major historical British events in digitized historical newspapers. ...

Constructing a Recipe Web from Historical Newspapers: 17th International Semantic Web Conference, Monterey, CA, USA, October 8–12, 2018, Proceedings, Part I
  • Citing Chapter
  • September 2018

Lecture Notes in Computer Science