Optical Navigation Shutter Interval Tuning for Mode Transitions

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Solution Overview

Problem

Conventional optical navigation devices struggle to accurately determine shutter intervals during mode transitions due to abrupt changes in pixel array characteristics, leading to inconsistent image statistics and inaccurate displacement calculations.

Innovation Solution

The optical navigation device employs a processor to identify mode transitions and adjust shutter intervals by capturing multiple shutter tuning frames with tunable intervals, using predetermined scaling factors to ensure consistent image statistics across frames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the shutter interval is adjusted based on pixel statistics of the previous image, then the statistical deviation between successive images is minimized under normal conditions, but the pixel statistics become inconsistent after a mode transition occurs

Engineering Contradiction:

Improvedisplacement determination accuracyVSAvoidadaptability to mode transitions

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary detection of mode transitions by analyzing pixel statistics before adjusting the shutter interval. When a mode transition is detected, the system proactively invokes shutter tuning frames to recalibrate the shutter interval, preventing statistical deviation issues rather than reacting to them after they occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Shutter tuning frames are introduced as an intermediary mechanism between the previous image and the next image. These intermediate frames capture the transition state and provide data for calculating a new shutter interval that bridges the statistical gap caused by mode transitions, ensuring smooth adaptation without direct discontinuity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If multiple shutter tuning frames are captured to determine a new shutter interval after mode transition, then image statistics consistency is restored, but the frame acquisition time and processing complexity increase

Engineering Contradiction:

Improveimage statistics consistencyVSAvoidshutter control logic complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The shutter adjustment process is segmented into distinct phases: normal operation mode, mode transition detection, shutter tuning frame acquisition, and new shutter interval application. This segmentation allows the complex logic to be activated only when needed (during mode transitions) rather than continuously, reducing overall system complexity while maintaining reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts its operational mode based on detected conditions. During normal operation, it uses simple sequential image acquisition. Upon detecting a mode transition through pixel statistic analysis, it dynamically switches to the shutter tuning frame acquisition mode, then returns to normal operation after recalibration, optimizing the balance between reliability and complexity.

Inventive Principle:

Principle #15Dynamics

3Illumination intensity

If the shutter interval is increased to capture more light after mode transition, then image quality improves, but the frame rate decreases and displacement measurement accuracy may be compromised

Engineering Contradiction:

Improvelight capture amountVSAvoidframe rate

Core Design Contradiction:

Illumination intensityVSSpeed

Solution Approach 1:

The system changes the shutter interval parameter adaptively based on mode transition detection. Instead of using a fixed or simply incremented shutter interval, it calculates an optimized new shutter interval that balances light capture requirements with frame rate maintenance, using the shutter tuning frames to determine the appropriate parameter value for the new operating conditions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12498798B2Optical navigation device capable of determining shutter interval with mode transition and operating method thereof

Publication Date: 2025.12.16 PIXART IMAGING INC

AI summary

There is provided an optical navigation device including a light sensor and a processor. The light sensor is configured to capture image frames using a predetermined frame period. The processor is configured to calculate image statistics according to a first image frame captured by the light sensor and determine an expected shutter interval for capturing a second image frame according to the image statistics. The processor is further configured to control the light sensor to capture additional shutter tuning frames between the first image frame and the second image frame upon confirming a mode transition at or prior to the first image frame.