The use of police drones is "poised to explode" in the next year as law enforcement takes advantage of the technology's proliferation, leaving public regulation and transparency efforts in danger of being caught woefully behind, civil rights advocates warn. "A world where flying robotic police cameras constantly crisscross our skies is one we have never seen before," Jay Stanley, senior policy analyst with the American Civil Liberties Union, wrote in a report released Thursday. "Yet there are strong reasons to believe that such a world may be coming faster than most people realize." At least 1,400 police departments across the country are using drones in some fashion, but only 15 have obtained waivers from the Federal Aviation Administration to fly their drones beyond the visual line of sight, or BVLOS, of operators. That means the vast majority of departments are still limited in the types of calls they can respond to with drones.

The rapid emergence of airborne platforms and imaging sensors are enabling new forms of aerial surveillance due to their unprecedented advantages in scale, mobility, deployment and covert observation capabilities. This paper provides a comprehensive overview of human-centric aerial surveillance tasks from a computer vision and pattern recognition perspective. It aims to provide readers with an in-depth systematic review and technical analysis of the current state of aerial surveillance tasks using drones, UAVs and other airborne platforms. The main object of interest is humans, where single or multiple subjects are to be detected, identified, tracked, re-identified and have their behavior analyzed. More specifically, for each of these four tasks, we first discuss unique challenges in performing these tasks in an aerial setting compared to a ground-based setting. We then review and analyze the aerial datasets publicly available for each task, and delve deep into the approaches in the aerial literature and investigate how they presently address the aerial challenges. We conclude the paper with discussion on the missing gaps and open research questions to inform future research avenues.

The revelation that a private company has been conducting secret aerial surveillance on behalf of the Baltimore Police Department -- collecting and storing footage from city neighborhoods in the process -- sparked confusion and outrage Wednesday among elected officials and civil liberties advocates. Some demanded an immediate halt to the program pending a full, public accounting of its capabilities and its use in the city to date, including in the prosecution of criminal defendants. Some called it "astounding" in its ability to intrude on individual privacy rights, and legally questionable in terms of constitutional law. Others did not fault the program but said it should have been disclosed publicly before it began in January. The program -- in which Ohio-based Persistent Surveillance Systems has for months been testing sophisticated surveillance cameras aboard a small Cessna airplane flying high above the city -- was first disclosed by Bloomberg Businessweek.