US 12,142,385 B2
Methods and systems for reducing a risk of spread of disease among people in a space
Vijay Dhamija, Cumming, GA (US); Lalitha M. Eswara, Bangalore (IN); Ismaiel Shaik, Bangalore (IN); Mourian Balasubramanian, Bangalore (IN); Abhisekh Jain, Madurai (IN); Siddharth Sonkamble, Mumbai (IN); Jitendra Chaurasia, Bengaluru (IN); and Manu Thomas, Pandalam (IN)
Assigned to HONEYWELL INTERNATIONAL INC., Charlotte, NC (US)
Filed by Honeywell International Inc., Charlotte, NC (US)
Filed on May 24, 2021, as Appl. No. 17/328,356.
Claims priority of provisional application 63/042,414, filed on Jun. 22, 2020.
Prior Publication US 2021/0398691 A1, Dec. 23, 2021
Int. Cl. G16H 50/80 (2018.01); G06V 20/40 (2022.01); G06V 20/52 (2022.01); G06V 40/20 (2022.01); G16H 40/20 (2018.01)
CPC G16H 50/80 (2018.01) [G06V 20/41 (2022.01); G06V 20/53 (2022.01); G06V 40/20 (2022.01); G16H 40/20 (2018.01); G06V 20/44 (2022.01)] 10 Claims
OG exemplary drawing
 
1. A method for counting a number of people in a space of a building, the method comprising:
storing a background image of a perspective field of view captured by a non-overhead video camera;
receiving a video stream from the non-overhead video camera;
calibrating the perspective field of view captured by the non-overhead video camera, including:
determining a number of pixels of the non-overhead video camera that correspond to a known-sized object at a known location at a near end of the perspective field of view of the non-overhead video camera, and a number of pixels of the non-overhead video camera that correspond to a known-sized object at a known location at a far end of the perspective field of view of the non-overhead video camera;
generating a calibration map that maps real world distances in the perspective field of view of the non-overhead video camera against x-and y-pixel positions of the non-overhead video camera based at least in part on the number of pixels of the non-overhead video camera that correspond to the known-sized object at the known location at the near end of the perspective field of view of the non-overhead video camera and the number of pixels of the non-overhead video camera that correspond to the known-sized object at the known location at the far end of the perspective field of view of the non-overhead video camera;
subtracting the background image from each frame of the video stream to identify one or more blobs in the perspective field of view of the non-overhead video camera;
determining a real-world distance between the non-overhead video camera and each of the one or more blobs based at least in part on the calibration map;
comparing a size of each of the one or more blobs to an expected size of a person at the determined distance of the corresponding blob;
when the size of the blob is greater than the expected size of a person at the determined distance of the corresponding blob by more than a factor of at least 1.5 times, counting the blob as two or more people, otherwise counting the blob as one person or no person; and
determining a count of the number people in the perspective field of view of the non-overhead video camera based at least in part on the count of people assigned to each of the one or more blobs.