Face-Weighted Auto Exposure for XR User Enrollment

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Solution Overview

Problem

Existing XR environments struggle with generating high-quality graphical representations of users due to suboptimal exposure settings during user enrollment processes, leading to grainy and tone-inaccurate avatars.

Innovation Solution

Implementing face-based autoexposure (AE) techniques that adjust exposure settings based on detected face location within sensor data, switching to scene average AE when the face is not detected, and using ROI-weighted AE when the face is present, along with fusion of multiple frames for higher dynamic range images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If scene average AE process is used during user enrollment, then the exposure settings are consistent with general passthrough video generation, but the exposure quality of face regions deteriorates leading to grainy and tone-inaccurate avatars

Engineering Contradiction:
Improveexposure qualityVSAvoidoperational simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent applies different AE processes to different regions of the sensor data. When face location data is detected, a first AE process (face-based AE) is applied specifically to the face region, while a second AE process (scene average AE) is applied to the overall scene. This local differentiation ensures optimal exposure quality for the face region without compromising the overall scene capture, directly resolving the contradiction between exposure quality and operational simplicity.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If face-based AE techniques are implemented during enrollment, then exposure quality of face regions improves, but device complexity increases due to face detection and mode switching mechanisms

Engineering Contradiction:
Improveexposure qualityVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamic switching between different AE processes based on the detection state. The system automatically transitions between scene average AE and face-based AE depending on whether face location data is detected, and adjusts the weight of face region pixels dynamically. This dynamic adaptation allows the system to achieve high exposure quality when needed while maintaining operational simplicity when face detection is not applicable, thereby managing device complexity effectively.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If ROI-weighted AE process is used with face location data, then detail accuracy of user faces improves, but processing time increases due to additional face detection and weighted processing

Engineering Contradiction:
Improvedetail accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs face detection and determines face location data in advance before applying the AE process. By pre-identifying the face region and preparing the weighted AE parameters beforehand, the system minimizes processing delays during the actual enrollment capture. This preliminary action allows the system to apply the computationally intensive ROI-weighted AE process efficiently, maintaining high detail accuracy while reducing the perceived processing time.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20250371781A1Face-Based Auto Exposure for User Enrollment
Publication Date: 2025.12.04 APPLE INC
  • US20250371781A1 patent drawing
  • US20250371781A1 patent drawing
  • US20250371781A1 patent drawing

AI summary

Facilitating the capture and processing of enrollment data includes: capturing, e.g., by a head-mounted display (HMD) device operating in a first mode (e.g., a passthrough video mode), first sensor data; performing a first autoexposure (AE) process (e.g., a scene average AE algorithm) on the first sensor data; and then determining that the HMD is operating in a second mode (e.g., a user enrollment mode) that is different than the first mode. Once operating in the second mode, the HMD may proceed by: capturing second sensor data; determining face location data for a subject detected in the second sensor data; performing a second AE process (e.g., a face-weighted AE algorithm) on the second sensor data; and generating a graphical representation for the subject (e.g., a so-called “Persona” or other three-dimensional avatar), based, at least in part, on the second sensor data that has had the second AE process performed on it.