Gain control for facial authentication

A document describes techniques and systems that enable automatic exposure and gain control for facial authentication. The techniques and systems include a user equipment using a default gain to initialize a gain of a near-infrared camera system. The user equipment ascertains patch mean statistics for one or more regions of interest of a recently captured image captured by a near infrared camera system. The user equipment computes an update in the initialized gain to provide an updated gain that can be used to scale the one or more regions of interest toward the target mean luminance value. The user equipment suppresses the updated gain by using hysteresis. The user equipment then sets the gain of the initialization of the near infrared camera system to the suppressed updated gain. 本文档描述能够实现用于面部认证的自动曝光和增益控制的技术和系统。所述技术和系统包括用户设备使用默认增益来初始化近红外相机系统的增益。用户设备查明由近红外相机系统捕获的最近捕获的图像的一个或多个感兴趣区域的面片均值统计数据。用户设备计算初始化的增益中的更新，以提供可用于朝向目标均值亮度值缩放一个或多个感兴趣区域的更新的增益。用户设备通过使用滞后来抑制更新的增益。然后，用户设备将近红外相机系统的初始化的增益设置为所抑制的更新的增益。