The complete picture: Visual Themes and Sentiment on Social Media for First Responders.

Researchers and academicians all over the world have conducted numerous studies and established that social media plays a vital role during crisis events. From citizens helping police to capture suspected terrorists Boston Marathon [5], to vigilant users spreading situational awareness [6], OSNs have proved their mettle as a powerful platform for information dissemination during crisis.

Most of the aforementioned work has relied on textual content posted on OSNs to extract knowledge, and make inferences. Now the thing is, that online media is rapidly moving from text to visual media. With the prevalence of 3G, 4G technologies and high-bandwidth connectivity in most Internet enabled countries, images and videos are gaining much more traction than text. This is also natural, since the human brain is hardwired to recognize and make sense of visual information more efficiently [1]. Just using text to draw inferences from social media data is no longer enough. As we discussed in our previous blog, there is a significant percentage of social media posts which do not contain any text. Moreover, there’s also a large percentage of posts which contain both text, and images. The point to keep in mind here is, that images and text may be contradicting each other, even if they’re part of the same post. While text in Figure 1 inspires support and positive sentiment, the image (or more precisely, the text in the image) is pretty negative. This is what current research methodology is missing out on http://followersguru.net/.

Example of Facebook post — Figure 1. Example of a Facebook post with contradicting text and image sentiment.

Continuing our work on image and online social media, we decided to dig further into images posted on social networks, and see if images could aid first responders to get a more complete picture of the situation during a crisis event. We collected Facebook posts published during the attacks in Paris in November 2015, and performed large scale mining on the image content we captured. Typically, monitoring the popular topics and sentiment among the citizens can be of help to first responders. Timely identification of misinformation, sensitive topics, negative sentiment, etc. online can be really helpful in predicting and averting any potential implications in the real world.

We were able to gather over 57,000 images using the #ParisAttacks and #PrayForParis hashtags put together, out of which, 15,123 images were unique. Analyzing such a big number of images manually is time consuming, and not scalable. So we utilized state-of-the-art techniques from the computer vision domain to automatically analyze images on a large scale. These techniques include Optical Character Recognition (OCR) [2], image classification, and image sentiment identification using Convolutional Neural Networks (CNNs). Figure 2 shows how a typical CNN model processes and classifies images [4].

Figure 2. Typical CNN model for object identification in images. Image taken from http://cs231n.github.io/convolutional-networks/

With all these “weapons”, we set out to mine the sea of images and see if we could discover something useful. And we struck gold right away. We used Google’s Inception-v3 model [3] for generating tags for images automatically, and looked at a few of the most popular tags. Interestingly, we found numerous instances of misinformative images, images containing potentially sensitive themes, and images promoting conspiracy theories among popular images. By the time we identified them, these images had gathered millions of likes, and hundreds of thousands of comments and shares. Some of these examples are listed below (Figure 3 – 6) at http://followersguru.net/buy-instagram-likes/.

Figure 3. Eiffel Tower turns off its lights for the first time in 63 years. This information was incorrect. Eiffel Tower’s lights are turned off every night between 1 am and 6 am following a ruling by the French Government.

Figure 4. Image incorrectly quoting the cause of death of Diesel, a police dog that helped the police during the attacks. The French Police later clarified that the actual cause of death was gunshot wounds from the French Police fleet itself, and not the suicide bomber.

Figure 5. Donald Trump’s insensitive tweet just after the Paris attacks. As the time stamp of the tweet suggests, this tweet was posted months ago, but resurfaced just after the attacks to defame the politician.

Figure 6. Picture claiming that a muslim guard named Zouheir stopped a suicide bomber from entering the Stade de France football stadium and saved thousands of lives. As later clarified by the security guard himself, such an incident never took place. Zouheir, the security guard was stationed at a different spot.

Applying OCR on the images in our dataset, we were able to extract text from about 55% of the images (31,869 out of 57,748 images). We wondered if this text embedded in images would be any different than the text that users post otherwise, in the orthodox manner. Upon analyzing and comparing the sentiment of image text and post text, we found that image text (extracted through OCR) was much more negative than post text (the orthodox text). In fact, not only was image text more negative, it was also different from post text in terms of topics being talked about. Table 1 shows a mutually exclusive subset of the most common words appearing in image text and post text. While post text was full of generic text offering prayers, support and solidarity, image text was found to mention some sensitive issues like “refugees”, “syria”, etc.

	Top words in posts		Top words in images
S. No.	Word	Normalized frequency	Word	Normalized frequency
1.	retweeted	0.005572571	house	0.00452941
2.	time	0.005208351	safety	0.004481122
3.	prayers	0.005001407	washington	0.004297628
4.	news	0.004713342	sisters	0.003940297
5.	prayfortheworld	0.004431899	learned	0.003863036
6.	life	0.004393821	mouth	0.003853378
7.	let	0.004249789	stacy	0.003751974
8.	support	0.004249789	passport	0.003708515
9.	god	0.00401139	americans	0.003694028
10.	war	0.003986557	refugee	0.00352502
11.	thoughts	0.003882258	japan	0.002887619
12.	need	0.003878946	texas	0.002781386
13.	last	0.003797825	born	0.002689639
14.	lives	0.003734914	dear	0.002689639
15.	said	0.003468371	syrians	0.002607549
16.	place	0.003468371	similar	0.002573748
17.	country	0.003319372	deadly	0.002568919
18.	city	0.003291227	services	0.002554433
19.	everyone	0.003281294	accept	0.002554433
20.	live	0.003274672	necessary	0.002549604

Table 1. Mutually exclusive set of 20 most frequently occurring
relevant keywords in post and image text, with their normalized
frequency. We identified some potentially sensitive topics among
image text, which were not present in post text. Word frequencies
are normalized independently by the total sum of frequencies of the
top 500 words in each class.

We also uncovered a popular conspiracy theory surrounding the Syrian “passports” that were found by French police near the bodies of terrorists who carried out the attacks, and were allegedly used to establish the identity of the attackers as Syrian citizens. Text embedded in images depicting this theme questioned how the passports could have survived the heat of the blasts and fire. This conspiracy theory was then used by miscreants to label the attacks as a false flag operation, influencing citizens to question the policies and motives of their own government. The popularity of such memes on OSN platforms can have undesirable outcomes in the real world, like protests and mass unrest. It is therefore vital for first responders to be able to identify such content and counter / control its flow to avoid repercussions in the real world.

Figure 7. Example of a picture containing text relating to a conspiracy theory questioning how the Syrian passports survived the blasts. We found hundreds of images talking about this topic in our dataset.

Images posted on OSNs are a critical source of information that can be useful for law and order organizations to understand popular topics and public sentiment, especially during crisis events. Through our approach, we propose a semi-automated methodology for mining knowledge from visual content and identifying popular themes and citizens’ pulse during crisis events. Although this methodology has its limitations, it can be very effective for producing high level summaries and reducing the search space for organizations with respect to content that may need attention. We also described how our methodology can be used for automatically identifying (potentially sensitive) misinformation spread through images during crisis events, which may lead to major implications in the real world.

Here is a link to the complete Technical report on this work. Big credits to Varun Bharadhwaj, Aditi Mithal, and Anshuman Suri for all their efforts. Below is an infographic of work.

References:

[1] https://www.eyeqinsights.com/power-visual-content-images-vs-text/

[2] https://github.com/tesseract-ocr/

[3] https://www.tensorflow.org/versions/r0.11/tutorials/image_recognition/index.html

[4] http://cs231n.github.io/convolutional-networks/

[5] Gupta, Aditi, Hemank Lamba, and Ponnurangam Kumaraguru. “$1.00 per rt# bostonmarathon# prayforboston: Analyzing fake content on twitter.” In eCrime Researchers Summit (eCRS), 2013, pp. 1-12. IEEE, 2013.

[6] Vieweg, Sarah, Amanda L. Hughes, Kate Starbird, and Leysia Palen. “Microblogging during two natural hazards events: what twitter may contribute to situational awareness.” In Proceedings of the SIGCHI conference on human factors in computing systems, pp. 1079-1088. ACM, 2010.