Arab Press

بالشعب و للشعب
Friday, Jun 20, 2025

How A.I. Helped Improve Crowd Counting in Hong Kong Protests

How A.I. Helped Improve Crowd Counting in Hong Kong Protests

Crowd estimates for Hong Kong’s large pro-democracy protests have been a point of contention for years. The organizers and the police often release vastly divergent estimates. This year’s annual pro-democracy protest on Monday, July 1, was no different. Organizers announced 550,000 people attended; the police said 190,000 people were there at the peak.

But for the first time in the march’s history, a group of researchers combined artificial intelligence and manual counting techniques to estimate the size of the crowd, concluding that 265,000 people marched.

The high density of the crowd and the moving nature of these protests make estimating the turnout very challenging. For more than a decade, groups have stationed teams along the route and manually counted the rate of people passing through to derive the total number of participants. Though the use of A.I. does not make the calculation definitive, the technology helps produce a more precise estimate because it uses computers to try to count every person.

Since 2003, Paul Yip, a social sciences professor at Hong Kong University, has been producing a count of the size of protests held annually on July 1, the anniversary of Hong Kong’s 1997 handover from Britain to China. With the hopes of creating a more robust estimate this year, Mr. Yip teamed up with Edwin Chow from Texas State University and Raymond Wong from C&R Wise AI, a local technology company, to use artificial intelligence to count the crowd at the march.


How A.I. Can Be Used to Count Crowds


Using open source software, The New York Times developed a computer model to illustrate how artificial intelligence could be used to recognize people and objects moving within a video.

Analyzing a short video clip recorded on Monday, The Times’s model tried to detect people based on color and shape, and then tracked the figures as they moved across the screen. This method helps avoid double counting because the crowd generally flowed in one direction.

Accurately detecting and tracking a moving object in such a high-density condition is very difficult. Overlapping of people in the crowd and obstructions like umbrellas, protest signs and large backpacks can often confuse the A.I. system.

On the day of the protest, Mr. Yip and the A.I. team used technology that is much more advanced. They spent weeks training their program to improve its accuracy in analyzing crowd imagery.

How A.I. Was Used to Count the July 1 Protest

On Monday, the A.I. team attached seven iPads to two major footbridges along the march route. Volunteers doing manual counts were also stationed next to the cameras, to help verify the computer count.

The team’s software ran multiple models with different parameters to track people in the crowd. People could be counted when they crossed a so-called counting line within the frame of the video. Throughout the day, the team monitored the results and adapted to changing variables like the density of people, the speed of flow and different lighting conditions.

“It’s all based on visual cues, such as the brightness value, color, shape, geometry of the pixels, all tied together,” said Mr. Wong, explaining how their system distinguished human figures from objects like umbrellas.

The team began exploring the possibility of doing a count with artificial intelligence in June, when protests in Hong Kong were gaining momentum. The newspaper Ming Pao and Cable News, both based in Hong Kong, provided additional support to the team.

“What we deserve is a more accurate, more precise, and more verifiable number,” said Mr. Yip.

Ahead of the demonstration on July 1, Mr. Yip and the A.I. team tested their software at other marches and crowded places to train and fine-tune the A.I. model developed by Mr. Wong, and to test out the best angles to shoot from. They did a trial run on June 16, another day of big protest in Hong Kong, when hundreds of thousands of people marched along the same route from Victoria Park to the government headquarters.

These trials helped them prepare for issues like obstruction and overlapping bodies in the crowd and gave them ideas on how to do a comprehensive count on July 1. For example, the team decided to train their system to detect umbrellas because they are common in Hong Kong protests.

Mr. Wong also rewrote the program to run on iPads rather than industrial computers, in order to scale up the operation. The team was then able to set up the devices at more locations. They also had several spares ready to be used in case there were significant numbers of people spilling over onto nearby streets, as happened on June 16.

Newsletter

Related Articles

Arab Press
0:00
0:00
Close
16 Billion Login Credentials Leaked in Unprecedented Cybersecurity Breach
Senate hearing on who was 'really running' Biden White House kicks off
G7 Leaders Fail to Reach Consensus on Key Global Issues
Mass exodus in Tehran as millions try to flee following Trump’s evacuation order
Iranian Military Officers Reportedly Seek Contact with Reza Pahlavi, Signal Intent to Defect
China's Iranian Oil Imports Face Disruption Amid Escalating Middle East Tensions
Trump Demands Iran's Unconditional Surrender Amid Escalating Conflict
Israeli Airstrike Targets Iranian State TV in Central Tehran
President Trump is leaving the G7 summit early and has ordered the National Security Council to the Situation Room
Netanyahu Signals Potential Regime Change in Iran
Analysts Warn Iran May Resort to Unconventional Warfare
Iranian Regime Faces Existential Threat Amid Conflict
Energy Infrastructure Becomes War Zone in Middle East
Iran Conducts Ballistic Missile Launches Amid Heightened Tensions with Israel
Iran Signals Openness to Nuclear Negotiations Amid Ongoing Regional Tensions
Shock Within Iran’s Leadership: Khamenei’s Failed Plan to Launch 1,000 Missiles Against Israel
UK Deploys Jets to Middle East Amid Rising Tensions
Exiled Iranian Prince Reza Pahlavi Urges Overthrow of Khamenei Regime
Wreck of $17 Billion San José Galleon Identified Off Colombia After 300 Years
Iran Launches Extensive Missile Attack on Israel Following Israeli Strikes on Nuclear Sites
Israel Issues Ultimatum to Iran Over Potential Retaliation and Nuclear Facilities
Coinbase CEO Warns Bitcoin Could Supplant US Dollar Amid Mounting National Debt
Trump to Iran: Make a Deal — Sign or Die
Operation "Like a Lion": Israel Strikes Iran in Unprecedented Offensive
Israel Launches 'Operation Rising Lion' Targeting Iranian Nuclear and Military Sites
Israeli Forces Intercept Gaza-Bound Aid Vessel Carrying Greta Thunberg
IMF Warns of Severe Global Trade War Impacts on Emerging Markets
Syria to Reconnect to Global Economy After 14 Years of Isolation
Saudi Arabia Faces Uncertainty Over Succession After Mohammed bin Salman
Israel Confirms Arming Gaza Clan to Counter Hamas Influence
Majority of French Voters View Macron's Presidency as a Failure
U.S. Reduces Military Presence in Syria
Trump Demands Iran End All Uranium Enrichment in Nuclear Talks
Iran Warns Europe Against Politicizing UN Nuclear Report
Businessman Mauled by Lion at Luxury Namibian Lodge
Paris Saint-Germain's Greatest Triumph Is Football’s Lowest Point
OPEC+ Agrees to Increase Oil Output for Third Consecutive Month
Turkey Detains Istanbul Officials Amid Anti-Corruption Crackdown
Meta and Anduril Collaborate on AI-Driven Military Augmented Reality Systems
EU Central Bank Pushes to Replace US Dollar with Euro as World’s Main Currency
European and Arab Ministers Convene in Madrid to Address Gaza Conflict
Head of Gaza Aid Group Resigns Amid Humanitarian Concerns
U.S. Health Secretary Ends Select COVID-19 Vaccine Recommendations
Trump Warns Putin Is 'Playing with Fire' Amid Escalating Ukraine Conflict
India and Pakistan Engage Trump-Linked Lobbyists to Influence U.S. Policy
U.S. Halts New Student Visa Interviews Amid Enhanced Security Measures
Trump Administration Cancels $100 Million in Federal Contracts with Harvard
SpaceX Starship Test Flight Ends in Failure, Mars Mission Timeline Uncertain
King Charles Affirms Canadian Sovereignty Amid U.S. Statehood Pressure
Iranian Revolutionary Guard Founder Warns Against Trusting Regime in Nuclear Talks
×