Optical Mouse Image Sensor Correlation Window Offset Control

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Solution Overview

Problem

Conventional image sensors in optical mice face inefficiencies in predicting the offset for the correlation window, particularly at low speeds with high frame rates, leading to unstable correlation window positioning.

Innovation Solution

An image processing method that compares frame deltas and frame rates with predetermined thresholds to adjust the frame rate and offset of the correlation window, ensuring a constant offset value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If prediction is used to estimate the next offset location for the correlation window, then the image sensor can operate at high frame rates, but the prediction becomes non-efficient and inaccurate at low speeds with high frame rates

Engineering Contradiction:

Improveframe rateVSAvoidoffset prediction accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the actual offset value from the current frame is fed back to adjust and correct the predicted offset for the next frame. The control unit compares the predicted offset with the actual offset and uses this feedback to refine future predictions, ensuring accurate correlation window positioning even at low speeds with high frame rates.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the offset value based on real-time motion conditions. Instead of using a fixed prediction method, the system adapts the offset calculation by considering the actual frame-to-frame displacement and motion characteristics, making the offset estimation dynamic and condition-dependent rather than static.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the correlation window offset varies due to optical mouse movement, then the image sensor can track motion, but the offset becomes unstable and difficult to predict

Engineering Contradiction:

Improvemotion tracking capabilityVSAvoidcorrelation window offset stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The control unit continuously monitors the actual offset value and uses this feedback to correct and stabilize the predicted offset for the next frame. This feedback loop ensures that even though the correlation window moves to track motion, the offset remains stable and predictable by constantly adjusting based on actual observed values.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the offset parameter dynamically based on motion conditions while maintaining stability through controlled adjustment. The system adjusts the offset value according to the actual displacement between frames, ensuring the parameter adapts to motion while remaining stable through systematic control rather than random variation.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9927884B2Non transitory computer readable recording medium for executing image processing method, and image sensing device applying the image processing method

Publication Date: 2018.03.27 PIXART IMAGING PENANG

AI summary

A non-transitory computer-readable medium storing a program causing a computer to execute an image processing method applied to an image sensing device. The image processing method comprises: (a) comparing a frame delta between a reference frame and a first frame with a predetermined threshold value to generate a first comparing result; (b) comparing a frame rate of the image sensing device with a minimum frame rate and/or a maximum frame rate, to generate a second comparing result; and (c) adjusting one of the frame rate and an offset for a correlation window of the image sensing device, according to the first comparing result and the second comparing result.