Optical Sensor Motion Delta Synchronization
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Solution Overview
Problem
Non-synchronization between the frame rate and MCU polling in optical pointing devices leads to inconsistencies in motion delta output, affecting the accuracy of position computation in optical pointing devices.
Innovation Solution
An image sensing system control method that calculates and outputs motion deltas based on time differences between image frames and polling events, ensuring that motion deltas are aligned with polling requests, thereby reducing the impact of synchronization issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the image sensor outputs motion delta responding to MCU polling requests, then the motion delta can be provided to the MCU for position computation, but the non-synchronization between frame rate and polling rate causes inconsistent numbers of motion deltas per polling and latency issues
Solution Approach 1:
The image sensor pre-calculates and stores motion deltas for multiple image frames before the MCU polling arrives. When a polling request is received, the sensor immediately outputs the pre-computed motion delta corresponding to the polling time, eliminating waiting time and ensuring consistent one-to-one correspondence between polling requests and motion delta outputs.
Solution Approach 2:
The patent introduces a timing synchronization mechanism that acts as an intermediary between the image sensor's frame rate and the MCU's polling rate. This intermediary aligns the output timing of motion deltas with the polling requests by calculating appropriate time differences, ensuring that each polling request receives exactly one motion delta at the correct time without latency or duplication.
2Loss of information
If the image sensor calculates motion delta between consecutive image frames, then motion information can be extracted for position tracking, but the non-synchronization causes motion deltas to be output at incorrect times relative to polling requests
Solution Approach 1:
The image sensor pre-calculates motion deltas for multiple consecutive image frames and stores them in a buffer before the MCU polling arrives. This preliminary calculation ensures that when the polling request is received, the corresponding motion delta is already ready for immediate output, eliminating timing delays and ensuring information is ready exactly when needed.
Solution Approach 2:
The patent implements a feedback mechanism where the image sensor monitors the timing relationship between frame capture and polling requests. Based on this feedback, the sensor adjusts when to output motion deltas, ensuring that each motion delta is output at the precise moment corresponding to its associated polling request, thereby maintaining accurate timing synchronization.
Data Source
AI summary
An image sensing system control method, comprises: (a) calculating a first motion delta between a first image frame and a second image frame following the first image frame by the image sensor; (b) calculating a first output motion delta according to a first time difference, a second time difference and the first motion delta by the image senor if the image senor receives a first polling from the control circuit, wherein the first time difference means a time difference between a time of the first polling and a time of the first image frame, and the second time difference means a time difference between a time of the first polling and a time of the second image frame; and (c) outputting the first output motion delta to the control circuit from the image sensor.