Dynamic Reference Block Sizing for Optical Navigation
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Solution Overview
Problem
Existing optical navigation methods face inefficiencies due to fixed reference block sizes, which compromise both calculation precision and efficiency, and require frequent updates, leading to increased calculation loading.
Innovation Solution
The method dynamically adjusts the size of the reference block and the area for block matching comparison based on the motion vector, generating an ancillary reference block with a smaller size in the direction of motion vector components, and updates it according to recent motion vectors to maintain precision while reducing calculation quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a larger reference block is used for block matching, then the precision for calculating correlation errors is improved, but the required calculation amount increases
Solution Approach 1:
The patent applies dynamics by making the reference block size variable rather than fixed. The system dynamically adjusts the reference block size based on the motion vector magnitude: using larger blocks when motion is small (to maintain precision) and smaller blocks when motion is large (to reduce calculation). This dynamic adaptation resolves the contradiction between precision and calculation efficiency.
Solution Approach 2:
The patent changes the parameter of reference block size based on motion vector characteristics. By modifying this key parameter according to motion conditions, the system achieves optimal balance between correlation error precision and calculation workload, directly addressing the technical contradiction.
2Productivity
If a smaller reference block is used for block matching, then the required calculation amount is reduced, but the precision for calculating correlation errors is lowered
Solution Approach 1:
The system dynamically selects reference block size based on motion conditions. When motion vectors indicate large displacement, smaller reference blocks are used to reduce the number of correlation calculations required, while still maintaining adequate precision for the given motion scale. This dynamic approach resolves the contradiction between calculation efficiency and precision.
Solution Approach 2:
The reference block size parameter is changed according to motion vector magnitude. This parameter adaptation allows the system to optimize the trade-off between calculation load and measurement precision, achieving high calculation efficiency without sacrificing necessary precision for the given motion conditions.
3Measurement precision
If the reference block is frequently updated to maintain precision, then the accuracy of motion vector calculation is improved, but the calculation loading increases greatly
Solution Approach 1:
The patent implements dynamic reference block updating based on motion vector characteristics. Instead of frequent updates, the system updates the reference block selectively based on motion magnitude and direction changes. This dynamic update strategy maintains calculation accuracy while significantly reducing unnecessary calculation loading from frequent updates.
Solution Approach 2:
The update frequency and timing of the reference block are changed based on motion conditions. By adapting the update parameter to motion characteristics, the system maintains high accuracy only when necessary, thereby reducing overall calculation loading while preserving motion vector calculation precision.
4Device complexity
If a fixed reference block size is used, then the device complexity is reduced, but both calculation efficiency and precision cannot be optimized simultaneously
Solution Approach 1:
The patent introduces dynamic reference block sizing with automatic adjustment based on motion vectors. While this increases device complexity compared to fixed-size blocks, it enables simultaneous optimization of both calculation efficiency and precision. The dynamic mechanism automatically adapts to different motion conditions, achieving performance optimization that fixed blocks cannot provide.
Solution Approach 2:
The reference block size parameter is made variable and is changed according to motion vector magnitude. This parameter change capability allows the system to optimize calculation efficiency and precision simultaneously, accepting increased device complexity as the necessary trade-off for achieving both goals.
Data Source
AI summary
The invention provides an optical navigation method, which includes: sequentially obtaining plural images including a first image, a second image, and a third image; choosing a main reference block in the first image; comparing the main reference block and the second image by block matching comparison to determine a first motion vector; resizing the main reference block according to the first motion vector to generate an ancillary reference block having a size smaller than the main reference block; and comparing the ancillary reference block and the third image by block matching comparison to determine a second motion vector.