Optical Navigation Object Detection for Cursor Stability
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Solution Overview
Problem
Optical finger navigation devices face challenges in accurately detecting finger lift-off to prevent power consumption and cursor skating, and they often experience unintended cursor movement or jittering when fingers are placed or lifted.
Innovation Solution
An optical finger navigation system with an integrated object detection engine that captures light-on and light-off frames using a variable shutter value, calculates a scaled-up pixel value, and applies a threshold to determine object presence, allowing navigation only when the finger is detected, and suspending operations when lifted, thereby reducing power consumption and preventing cursor jittering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional lift detection systems or object detection systems are implemented to prevent cursor skating and save power, then power consumption is reduced and cursor stability is improved, but device complexity increases and design integration becomes more difficult
Solution Approach 1:
The navigation sensor's existing image processing pipeline is leveraged to perform object detection. The sensor captures images and the processing circuitry analyzes them for object presence, using the same hardware resources already allocated for navigation functionality. This self-service approach eliminates dedicated detection hardware while achieving lift-off detection.
Solution Approach 2:
The image sensor and processing circuitry are designed to serve dual purposes: conventional optical navigation tracking and object presence detection. By making the navigation system multi-functional, the patent avoids adding separate detection components, thereby reducing device complexity while still achieving power savings and cursor stability.
2Measurement precision
If multiple images are captured for comparison in object detection systems, then object presence detection accuracy is improved, but the LED must be turned on at all times increasing power consumption
Solution Approach 1:
Instead of continuously illuminating with the LED, the system uses periodic or pulsed illumination in conjunction with the sensor's natural image capture cycles. The processing circuitry is configured to analyze captured images for object presence during regular navigation operations, allowing accurate detection while minimizing LED activation time and associated power consumption.
Solution Approach 2:
The system maintains continuous object detection capability by utilizing the ongoing image capture process inherent to optical navigation. Rather than initiating separate detection operations that would require additional LED activation, the navigation system's continuous image acquisition is repurposed for simultaneous object presence monitoring, eliminating redundant power consumption.
3Speed
If the sensor captures images continuously for navigation, then navigation responsiveness is improved, but unintended cursor movement occurs when finger is placed or lifted
Solution Approach 1:
The processing circuitry continuously analyzes captured images to detect object presence and provides feedback to control navigation operation. When an object is detected, navigation is enabled; when no object is present (finger lifted), navigation is suspended. This feedback mechanism prevents unintended cursor movement during finger placement or lift-off while maintaining responsive navigation during active use.
Solution Approach 2:
The navigation system dynamically adjusts its operational state based on real-time object detection results. The system transitions between active navigation mode and suspended mode according to finger presence, allowing responsive operation when needed while preventing cursor instability during transition periods when the finger is being placed or removed.
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
Effectively detects finger presence and absence to suspend navigation operations, reducing power usage and eliminating unintended cursor movements, enhancing user experience by preventing cursor skating and jittering.
Implementation Method 1
Light is illuminated towards the navigation surface or a target object by a light source... images of the illuminated navigation surface or multiple frames of digital image data of the illuminated target object are captured by the sensor
Data Source
AI summary
An optical finger navigation system with object detection is provided for preventing cursor movement if a user's finger has been lifted from the navigation surface. The optical finger navigation system may include a light source, an image sensor and an object detection engine. The object detection engine may be operatively coupled with the image sensor and the light source to selectively report motion data upon determining the presence of an object by comparing a scaled-up pixel value with a threshold value. The lift detection engine may be incorporated in a microcontroller, wherein the microcontroller may be added to a navigation system to provide an additional object detection feature.