Optical Mouse Frame Anchoring for Accurate Low-Speed Tracking
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Solution Overview
Problem
Existing optical mouse tracking methods experience accuracy degradation at low speeds due to minimum sampling rate limitations, leading to increased positional variance and noise in cursor movement.
Innovation Solution
The frame anchoring method selectively stores and compares frames to maintain tracking accuracy at low speeds by decoupling displacement variance from temporal sampling rate, using anchor frames to normalize variance to distance traveled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a minimum sampling rate is imposed to meet host reporting requirements, then the system can maintain responsiveness and meet reporting deadlines, but tracking accuracy degrades at low speeds due to insufficient displacement between frames
Solution Approach 1:
The patent segments the continuous stream of captured frames into two categories: intermediate frames and anchor frames. Intermediate frames are processed at the minimum sampling rate to meet host reporting requirements, while anchor frames are selectively retained and used for high-accuracy displacement measurements. This segmentation allows the system to maintain responsiveness through intermediate frames while ensuring measurement accuracy through anchor frames, even at low mouse speeds.
Solution Approach 2:
The patent extracts and retains specific frames (anchor frames) from the continuous stream of captured frames based on displacement thresholds. By extracting only those frames that meet the minimum displacement criterion, the system ensures that each anchor frame provides sufficient spatial information for accurate displacement measurement, while discarding or not retaining intermediate frames that do not meet the threshold.
2Measurement precision
If the sampling rate is increased to improve tracking accuracy at low speeds, then measurement precision improves, but power consumption and processing requirements increase
Solution Approach 1:
The patent implements a dynamic frame retention strategy where the sampling behavior adapts based on mouse velocity. At low speeds, the system retains anchor frames at higher effective rates to maintain accuracy. At higher speeds, the minimum sampling rate suffices. This dynamic approach optimizes power consumption by avoiding unnecessary high-rate sampling when not needed, while maintaining accuracy when required.
3Measurement precision
If multiple frames are stored in memory to improve displacement measurement accuracy, then measurement precision improves, but memory requirements and device complexity increase
Solution Approach 1:
The patent extracts and retains only the essential frames (anchor frames) needed for accurate displacement measurement, discarding intermediate frames that do not meet the displacement threshold. This selective retention minimizes memory usage while maintaining measurement accuracy, as only frames with sufficient spatial separation are stored for comparison.
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
This method ensures consistent tracking accuracy across all speeds without increasing memory, power, or processing requirements, improving precision in slow mouse movements.
Implementation Method 1
An optical mouse is a computer mouse which uses a light source, typically a light-emitting diode (LED), and a light detector, such as an array of photodiodes, to detect movement of the mouse relative to a surface.
Implementation Method 2
The optical mouse takes a picture of the surface it sits upon, and then after moving slightly, it takes another picture.
Data Source
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AI summary
A method is provided for tracking a position of an optical computer mouse based on determining a spatial displacement between image frames. A respective image frame is considered as an anchor frame if the respective image frame comes first in a sequence of image frames or the distance of the respective image frame to its immediately previous anchor frame is equal to or greater than a displacement threshold, and the respective image is considered as an intermediate frame if its distance to its immediately previous anchor frame is below the displacement threshold. Only anchor frames are stored in memory and used for future displacement measurements between image frames captured by the mouse.