According to the report, photos were taken at five different times (1:58 pm, 2:40 pm, 3:16 pm, 3:53 pm and 4:35 pm) and eight images from 3:53 pm were selected
The Political Debate Monitor of the University of São Paulo (USP) and the Brazilian Center for Analysis and Planning (Cebrap), in partnership with the organization More in Common, released a report estimating 20,400 people present at the demonstration called by supporters of former president Jair Bolsonaro (PL), on Avenida Paulista, in São Paulo, this Sunday, March 1st. According to the survey, the margin of error is 12%.
According to those responsible for the document, the estimate is therefore between 18 thousand and 22.9 thousand participants at the peak time of the demonstration, at 3:53 pm.
According to the report, photos were taken at five different times (1:58 pm, 2:40 pm, 3:16 pm, 3:53 pm and 4:35 pm) and eight images from 3:53 pm were selected.
The authors of the study say that the method used, Point to Point Network (P2PNet), was developed by researchers at the University of Chequião, in China and the company Tencent.
The document says that the software was trained with a set of crowd photos annotated manually by Shanghai University and another set of Brazilian photos annotated by USP.
The method, according to the authors, has a precision of 72.9% and an accuracy of 69.5% in identifying each individual, with an average absolute percentage error of 12% for groups above 500 people.
“In the method, a drone takes aerial photos of the crowd and the software analyzes these images to automatically identify and 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”, says the report.
*Estadão Content
