Savvas Petridis

I build tools that leverage both human and machine intelligence to tackle complex problems, such as designing visual representations for abstract ideas and fact checking.

I am a second year PhD student in computer science at Columbia University, advised by Prof. Lydia Chilton.

Visual Metaphors

Visual metaphors are an advanced graphic design technique used in news, advertising and public service announcements to draw users' attention to a message. They blend two objects together in a way that is novel and useful in conveying a message symbolically.

Professional examples:

The Economist article on the left illustrates "Brazil takes off" by symbolizing Brazil with the iconic Brazilian statue Christ the Redeemer and blending it with a rocket literally taking off. The middle advertisement associates Tabasco with heat by blending the hot sauce bottle with a fire extinguisher. The public service announcement on the right shows the Earth melting by blending it with an ice cream cone.

We have created a system that decomposes the process of making visual blends into a pipeline of human microtasks and computational techniques. The pipeline follows the iterative design process with steps involving brainstorming, synthesis, and iteration.

The Visual Metaphor Pipeline:

We ran 5 case studies where groups of 2 or 3 people familiar with the pipeline collaborated to make a visual metaphor for a message. Here are the results:

Metaphors produced for the 5 messages in the study, with aesthetic improvements done by the users:

Current Work:

The metaphors created in the study above were all associations between two nouns, but there exists an even more exciting subset of metaphors that involve a noun and a verb. We saw two examples in the professional metaphors at the beginning: "Brazil + Take off" and "Earth + Melt". Note that in these two examples the symbol for the verb is a noun that is undergoing said verb.

Here are three more examples of visual metaphors that blend a noun and a verb:

I am currently investigating strategies to semi-automate the search for symbols that can represent verbs. One such strategy is to expand a verb into a set of synonyms and hypnernyms. We can then search these terms individually in an image database.


VisiBlends: A Flexible Workflow for Visual Blends.
Lydia B. Chilton, Savvas Petridis, Maneesh Agrawala.
accepted to CHI 2019

Where is your Evidence: Improving Fact-checking by Justification.
Tariq Alhindi, Savvas Petridis, Smaranda Muresan.
FEVER Workshop at EMNLP 2018

AMuSe: Large-scale WiFi video distribution - Experimentation on the ORBIT testbed
Varun Gupta, Raphael Norwitz, Savvas Petridis, Craig Gutterman, Gil Zussman, Yigal Bejerano.
Demo description in Proc. IEEE INFOCOM'16, 2016

WiFi multicast to very large groups - experimentation on the ORBIT testbed
Varun Gupta, Raphael Norwitz, Savvas Petridis, Craig Gutterman, Gil Zussman, Yigal Bejerano.
Demo at IEEE LCN'15, 2015.