Optical Mouse Noise Removal via Reference Frame Subtraction

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Solution Overview

Problem

Conventional optical computer mice suffer from displacement calculation errors due to spatial noise patterns introduced by contamination and intensity variations in image frames, degrading tracking performance.

Innovation Solution

An optical navigation system that includes a spatial noise pattern estimation module to produce an estimate of the noise pattern, a normalization module to remove this noise from captured frames, and a navigation engine to generate displacement values based on normalized frames, thereby improving tracking accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional optical navigation systems capture image frames directly without noise removal, then the system structure remains simple, but displacement calculation errors occur due to spatial noise patterns from contamination and intensity variations

Engineering Contradiction:

Improvedisplacement estimation accuracyVSAvoidimage processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by capturing multiple reference image frames before actual navigation and computing a reference average frame in advance. This reference average frame is then used to remove spatial noise patterns from subsequently captured image frames, improving displacement estimation accuracy without adding complex real-time processing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent creates a copy of the spatial noise pattern by generating a reference average frame that captures the static contamination patterns and intensity variations. This reference frame serves as a template that is subtracted from subsequent frames to remove the noise patterns, effectively copying and eliminating the harmful spatial variations

Inventive Principle:

Principle #26Copying

2Reliability

If multiple image frames are captured and processed to remove spatial noise patterns, then tracking accuracy improves, but the processing time and computational load increase

Engineering Contradiction:

Improvetracking performanceVSAvoidimage processing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs noise pattern removal in advance by capturing multiple reference frames and computing the reference average frame before actual navigation begins. This preliminary processing separates the time-consuming operations from real-time tracking, maintaining high reliability while minimizing processing time during active use

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses its own captured image frames to generate the reference average frame, which then serves to clean subsequent frames. The captured frames themselves provide the data needed for their own purification, eliminating the need for external calibration targets or additional hardware

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8189954B2System and method for performing optical navigation using enhanced frames of image data

Publication Date: 2012.05.29 PIXART IMAGING INC

AI summary

A system and method for performing optical navigation uses a spatial noise pattern estimate of the spatial noise pattern in captured frames of image data caused by contamination on at least one component of the system to substantially remove the spatial noise pattern in the captured frames of image data before the captured frames of image data are used for displacement estimation.