US 12,170,854 B2
Noise-reduction circuit for an image sensor
Tsung-Hsun Tsai, Redmond, WA (US); and Lyle David Bainbridge, Redwood City, CA (US)
Assigned to Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed by Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed on Sep. 22, 2022, as Appl. No. 17/950,199.
Claims priority of provisional application 63/252,420, filed on Oct. 5, 2021.
Prior Publication US 2023/0105527 A1, Apr. 6, 2023
Int. Cl. H04N 25/673 (2023.01)
CPC H04N 25/673 (2023.01) 19 Claims
OG exemplary drawing
 
1. A noise-reduction circuit comprising:
a reference frame generator configured to generate a reference frame based on a plurality of image frames generated by an image sensor during a calibration phase in which pixels of the image sensor do not capture light;
a memory coupled to the reference frame generator, the memory being configured to receive the reference frame from the reference frame generator and store the reference frame for subsequent use during a first noise-reduction phase that is subsequent to the calibration phase; and
a processor coupled to the memory, the processor being configured to:
during the first noise-reduction phase, retrieve the reference frame from the memory and use the reference frame to reduce noise in an image frame received from the image sensor;
subsequent to the first noise-reduction phase, initiate a recalibration phase in which a new reference frame is generated based on the reference frame and at least one additional image frame generated by the image sensor; and
subsequent to the recalibration phase, initiate a second noise-reduction phase in which the new reference frame is used to reduce noise in multiple image frames received from the image sensor.