Protest Against the Armor PEC and Amnesty Project in SP Had 42.4 Thousand People at its Peak

At its peak, the protest on Avenida Paulista this Sunday (21) against the Armor PEC and the project that grants amnesty to people convicted on January 8 had 42.4 thousand people, according to researchers from the University of São Paulo (USP). The estimate by the Monitor of Political Debate team at Cebrap, done in partnership with the NGO More in Common, refers to the audience present at the event at 4:06 pm. It was produced using aerial photos and counted the audience with the aid of software. With the survey’s margin of error, there were between 37.3 thousand and 47.5 thousand people present. For comparison, the demonstration held in São Paulo on September 7 by supporters of former President Jair Bolsonaro (PL) in favor of amnesty brought together 42.2 thousand people, according to the same methodology. Participants chanted slogans against amnesty and carried signs and banners. A giant flag of Brazil was also unfurled as a counterpoint to the act that took place on September 7, where supporters of former President Jair Bolsonaro demonstrated in favor of amnesty, and when a flag of the United States was also unfurled on Avenida Paulista. The protest, peaceful, began around 2 pm and was called on social media by left-wing movements and also took place in other cities across the country. At least four blocks of the avenue were occupied. Two rain showers in the area reduced the number of protesters. Photos were taken at four different times: 2:10 pm, 2:45 pm, 3:22 pm, and 4:06 pm throughout the demonstration, totaling 38 images. Eleven photos taken at 4:06 pm, the peak moment of the event, were selected. The images covered the entire length of the demonstration without overlap. The Point to Point Network (P2PNet) method was used for crowd calculation, developed by researchers from Chequião University in China and the Tencent company. The software was trained with an annotated dataset of crowd photos from Xangai University and another annotated dataset of Brazilian photos from the University of São Paulo. In the method, a drone takes aerial photos of the crowd and the software analyzes these images to identify and automatically mark people’s heads. Using artificial intelligence, the system locates each individual and counts how many points appear in the image. This process ensures an accurate count, even in dense areas. The method currently has a precision of 72.9% and an accuracy of 69.5% in identifying each individual. This practically means there is an average absolute percentage error of 12%, meaning in measuring an audience of 100 thousand people, the actual value can range from 88 thousand to 112 thousand (12 thousand less or more).