Pen-Type XR Controller Layout for Occlusion-Resistant Pose Tracking

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Solution Overview

Problem

Existing tracking systems for XR controllers face challenges in accurately detecting the position and orientation of the controller due to LED obstruction by the user's hand and the high cost of using cameras with global shutters, which are necessary for high accuracy.

Innovation Solution

A pen-type controller design with strategically placed LEDs and a tracking system using cameras with rolling shutters positioned to minimize distortion, allowing for accurate detection of the controller's position and orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If LEDs are disposed on the controller surface for tracking, then the controller can be detected by the tracking system, but the LEDs may be hidden by the user's hand making detection inaccurate

Engineering Contradiction:

Improvedetection accuracy of controller position and orientationVSAvoidLED obstruction by user's hand

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies dimensionality change by transitioning from 2D LED arrangement on the controller surface to 3D spatial distribution of multiple light sources. By placing LEDs at different positions (pen tip, grip portion, and intermediate positions) along the longitudinal axis of the controller, the system creates a three-dimensional light source configuration. This allows the tracking system to detect the controller's position and orientation even when some LEDs are partially obscured, as other LEDs at different spatial locations remain visible, thereby resolving the obstruction problem while maintaining detection accuracy.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If a camera with global shutter is used to reduce video distortion for accurate tracking, then detection accuracy improves, but the system cost increases significantly

Engineering Contradiction:

Improvedetection accuracy of controller position and orientationVSAvoidsystem cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies the principle of using cheaper components by replacing expensive global shutter cameras with more affordable rolling shutter cameras. By compensating for the distortion introduced by rolling shutters through software algorithms and optimized LED placement, the system achieves comparable tracking accuracy at significantly reduced hardware cost. This substitution of expensive imaging devices with cheaper alternatives while maintaining performance aligns with the specified principle.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent applies parameter changes by modifying the shutter type from global to rolling and compensating through algorithmic adjustments. The tracking system uses rolling shutter cameras which introduce temporal distortion, but this is counteracted by implementing distortion compensation algorithms that adjust the captured video frames. Additionally, the strategic placement of multiple LEDs at different positions along the controller creates a spatial pattern that helps the system distinguish and correct for rolling shutter distortion effects, thereby maintaining tracking accuracy despite the parameter change in camera technology.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If multiple LEDs are disposed on the controller for tracking, then detection capability is enhanced, but the complexity of the controller increases

Engineering Contradiction:

Improvedetection accuracy of controller position and orientationVSAvoidcontroller structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the controller into distinct functional zones along its longitudinal axis, with LED placement corresponding to these segments. The controller is segmented into the pen tip portion, intermediate portion, and grip portion, with LEDs strategically positioned in each segment. This segmented approach allows the tracking system to detect different aspects of controller pose (position, orientation, and even grip detection) using LEDs at different locations, enhancing detection capability while organizing the added complexity in a structured, manageable way.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables precise detection of the controller's position and orientation with reduced cost by using rolling shutters, minimizing LED obstruction and video distortion.

Implementation Method 1

a first light emitting part disposed at an end part of the grip portion which is closer to the axis direction (or the axis) of the pen portion than another end part of the grip portion

Methodology Applied

Scientific EffectLight emitting diode (LED): Light Emitting Diode

Data Source

PatentUS12504835B2Controller and tracking system

Publication Date: 2025.12.23 WACOM CO LTD

AI summary

A pen-type controller includes a pen portion having a pen shape, a grip portion that intersects an axis direction of the pen portion, and a first light emitting part disposed at an end part of the grip portion, wherein the end part is closer to the axis of the pen portion than another end part of the grip portion.