Mr Yeo Kiat Nern, 28, a Q Team engineer, said shadows, light sources and reflections led to an inflated number of attendees.
He said: “Trees, reflections on water, balloons, or even fairy lights would be misidentified as heads, and could significantly contribute to the number of misidentified persons.”
The Q-Crowd Counter was updated and tested at least three more times: at the Marina Bay Singapore Countdown in 2022, the Chinese New Year bazaar at Chinatown in 2023, and ZoukOut again in 2023.
It is now more than 80 per cent accurate.
But for the Home Team Unmanned Aerial Vehicle (UAV) Unit, this is not yet enough for it to be used operationally.
Superintendent Sum Tuck Meng, head of UAV operations and training at the Home Team UAV Command, said it is important to have such technologies to prevent incidents like the South Korea Halloween crowd crush that killed at least 155 people in 2022.
He said he is appreciative of the Q-Crowd Counter and the team behind it, even though it remains in development.
But because of their persistence, the project was awarded the Undaunted Award in May 2024.
Dr Ng Gee Wah, 60, director of the Q Team, said it is hopeful that the counter will one day be used for police operations, and that the award was encouraging.
He said: “It’s a morale booster that after each iteration, even though we didn’t meet expectations, we are still encouraged to keep improving.
“Failure is part and parcel of life. We all fail at one point or another and we have to learn to stand up and just keep trying.”