公开(公告)号：US11687635B2

公开(公告)日：2023-06-27

申请号：US17439762

申请日：2019-09-25

Applicant: Google LLC

Inventor： Adarsh Prakash Murthy Kowdle ,  Ruben Manuel Velarde ,  Zhijun He ,  Xu Han ,  Kourosh Derakshan ,  Shahram Izadi

IPC: G06F21/32 ,  H04N5/33 ,  H04N23/72 ,  H04N23/71 ,  G06V10/22 ,  G06V10/143 ,  G06V40/16

CPC classification number: G06F21/32 ,  G06V10/143 ,  G06V10/235 ,  G06V40/166 ,  H04N5/33 ,  H04N23/71 ,  H04N23/72

Abstract: This document describes techniques and systems that enable automatic exposure and gain control for face authentication. The techniques and systems include a user device initializing a gain for a near-infrared camera system using a default gain. The user device ascertains patch-mean statistics of one or more regions-of-interest of a most-recently captured image that was captured by the near-infrared camera system. The user device computes an update in the initialized gain to provide an updated gain that is usable to scale the one or more regions-of-interest toward a target mean-luminance value. The user device dampens the updated gain by using hysteresis. Then, the user device sets the initialized gain for the near-infrared camera system to the dampened updated gain.

公开(公告)号：US20220191374A1

公开(公告)日：2022-06-16

申请号：US17439762

申请日：2019-09-25

Applicant: Google LLC

Inventor： Adarsh Prakash Murthy Kowdle ,  Ruben Manuel Velarde ,  Zhijun He ,  Xu Han ,  Kourosh Derakshan ,  Shahram Izadi

IPC: H04N5/235 ,  G06F21/32 ,  G06V10/25 ,  H04N5/33

Abstract: This document describes techniques and systems that enable automatic exposure and gain control for face authentication. The techniques and systems include a user device initializing a gain for a near-infrared camera system using a default gain. The user device ascertains patch-mean statistics of one or more regions-of-interest of a most-recently captured image that was captured by the near-infrared camera system. The user device computes an update in the initialized gain to provide an updated gain that is usable to scale the one or more regions-of-interest toward a target mean-luminance value. The user device dampens the updated gain by using hysteresis. Then, the user device sets the initialized gain for the near-infrared camera system to the dampened updated gain.