Capacitive Facial Tracking Sensor for Avatar Expression Control

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Solution Overview

Problem

Avatars in computing devices lack the ability to effectively convey user facial expressions, which is crucial for interpersonal communication, especially in AR and VR environments. Existing solutions, such as using cameras, face integration challenges in compact head-mounted devices and consume significant power.

Innovation Solution

Utilizing a facial tracking sensor system with one or more facial tracking sensors to receive sensor values, determine interpolated values within a blendshape range, and map these values to blendshape mappings, ultimately providing expression data to control computer-generated facial expressions on an avatar.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a camera is used to capture user facial expressions for avatar control, then the avatar can display accurate facial expressions, but the device becomes more complex and consumes significant power

Engineering Contradiction:

Improvefacial expression detection accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the optical camera system with an electrical sensing system using capacitive sensors. Instead of using light to capture facial expressions, the system uses changes in electrical capacitance caused by facial muscle movements to detect and map expressions to the avatar, thereby reducing device complexity and power consumption while maintaining expression detection capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an electrical copy of facial expression data through capacitive sensing. Rather than capturing optical images of the face, the system measures electrical field changes that correlate with facial movements and creates a digital representation of these movements that can be directly mapped to avatar controls, simplifying the overall system

Inventive Principle:

Principle #26Copying

2Measurement precision

If a camera is used to capture user facial expressions, then accurate expression data can be obtained, but power consumption increases significantly

Engineering Contradiction:

Improvefacial expression detection accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

The patent replaces the power-intensive camera system with low-power capacitive sensors. The electrical sensing mechanism requires minimal power to detect facial muscle movements through capacitance changes, dramatically reducing power consumption while maintaining the ability to capture accurate facial expression data for avatar control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs simple, low-cost capacitive sensing elements that consume minimal power compared to continuous camera operation. These sensors provide sufficient expression detection capability for the application while being energetically efficient, especially important for mobile and head-mounted device contexts

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If a camera is integrated into a head-mounted device for facial tracking, then facial expressions can be captured, but integration becomes difficult

Engineering Contradiction:

Improvefacial expression tracking capabilityVSAvoidintegration difficulty

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the optically complex camera system with electrically simple capacitive sensors that can be easily integrated into head-mounted devices. The electrical sensing components require fewer mechanical adjustments and have simpler integration requirements compared to camera systems, making manufacturing and device assembly more straightforward

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The capacitive sensor array can serve multiple functions beyond just facial expression tracking, including proximity detection and touch sensing, which simplifies the overall device design and reduces the number of separate components needed, thereby easing integration into head-mounted displays

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12320888B2Controlling computer-generated facial expressions

Publication Date: 2025.06.03 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Examples are disclosed that relate to utilizing a facial tracking sensor for controlling computer-generated facial expressions. One example provides a method of controlling computer-generated facial expressions. The method comprises receiving a sensor value acquired via a facial tracking sensor and determining an interpolated value for the sensor value within a value range. The value range corresponding to a blendshape range for a facial expression. The method further comprises determining a blendshape mapping based at least upon the interpolated value, determining expression data based at least upon the blendshape mapping, and providing the expression data to a device.