CIDAR contest tests the boundaries of passive ranging

The Defense Advanced Research Projects Agency has closed its Computational Imaging Detection and Ranging (CIDAR) challenge without awarding the top prizes, citing the steep technical bar it set for passive, long‑range depth sensing. The competition asked teams to build passive imaging algorithms capable of measuring distances out to 10 kilometers with the accuracy and latency of today’s active ranging systems; none met the minimum performance threshold in the final round.

“CIDAR captures the spirit of DARPA. We take big swings at problems where success is far from guaranteed because that is how we learn what technology can achieve today, and where more work needs to be done,” said Jonathan Hoffman, Ph.D, deputy director of DARPA’s Multi X Office. “In this case, no team cleared the bar we set, but they pushed the boundaries of passive ranging and gave us a much clearer understanding of what works, what doesn’t, and what still needs to be solved. That is valuable progress.”

Active optical ranging—such as lidar and laser range finders—delivers precise distance measurements but can expose an observer by emitting signals. Passive techniques avoid emissions but typically extract far less depth information from images. CIDAR’s goal was to narrow that gap by leveraging computational imaging, machine learning, and artificial intelligence.

Announced in December 2024, the program advanced through multiple stages. Five small businesses and universities received initial awards of $200,000 apiece, and another five teams earned $50,000 semifinal prizes in January 2026. For the final phase, competitors analyzed a fresh dataset for the chance at prizes of $1 million, $600,000, and $400,000, contingent on meeting a defined minimum performance level across targets from 2.5 to 10 kilometers. No team crossed that bar; Zetascope came closest to the required metrics, showing what DARPA called particularly promising progress.

While the finish line proved out of reach this round, DARPA said the challenge clarified the advances still needed to achieve accurate, low‑latency passive ranging at long distances and provided a foundation for future efforts in the field.