Navigation Track Smoothing With N-Tap Digital Filtering
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Solution Overview
Problem
Conventional optical mice experience track disturbance and zigzag paths due to noise in image frames, particularly noticeable in high-resolution settings, leading to unsmooth navigation.
Innovation Solution
A navigation device employing an N-tap digital filter with a delay buffer, accumulation buffer, calculation unit, and adder to perform track smoothing by calculating and averaging input data, with adjustable smoothing strength based on resolution settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noise filtering is applied to image frames, then measurement precision is improved, but device complexity increases
Solution Approach 1:
An N-tap digital filter is introduced as an intermediary component between the image sensor and the displacement calculation process. The filter receives raw displacement data from the processing unit and applies smoothing through averaging operations using delay buffers and accumulation buffers, effectively reducing noise without requiring complex modifications to the core image processing algorithms.
Solution Approach 2:
The patent changes the parameter of displacement data by applying an averaging operation with N taps (where N can be 8, 16, 32, 64, or higher). This parameter transformation smooths the displacement track by computing weighted averages of recent measurements, thereby improving measurement precision while keeping the processing unit architecture relatively simple.
2Measurement precision
If high resolution setting is used, then measurement precision is improved, but object-affected harmful factors increase
Solution Approach 1:
The patent converts the harmful effect of noise, which becomes more pronounced at high resolutions, into a benefit by applying a digital filtering operation. The N-tap filter uses the redundancy in consecutive displacement measurements to average out noise components, transforming the problematic high-sensitivity condition into an opportunity for improved signal-to-noise ratio through statistical averaging.
3Stability of the object's composition
If track smoothing is applied, then stability is improved, but loss of information increases
Solution Approach 1:
The patent applies partial smoothing by using an N-tap filter where N is chosen based on the specific application requirements. By adjusting the number of taps (e.g., 8, 16, 32, 64), the system can achieve the minimum necessary smoothing to stabilize the navigation track while preserving sufficient displacement information, avoiding excessive smoothing that would cause information loss.
Data Source
AI summary
A navigation device including a digital filter configured to smooth tracking is provided. The digital filter is configured to sequentially receive input data and output a tap sum, and calculate a quotient and a remainder by dividing an accumulation value with an average number, wherein the remainder is feedback to the tap sum for updating the accumulation value and the quotient is configured as output data.