Two-Dimension Position Encoder Using Interlaced Absolute Code
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing two-dimensional position measurement systems using color codes are sensitive to lighting conditions and dust, require high processing power for error correction, and have limited resolution due to large pattern sizes needed for micron-level precision.
Innovation Solution
A two-dimensional code comprising a two-dimensional absolute code interlaced with a regular pattern, where the absolute code is constructed using unique binary values and a method for decoding and computing the camera's position relative to the object using a camera, allowing for precise position determination with improved resilience to errors and reduced processing power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a two-dimension code with micron-level resolution is used, then measurement precision is improved, but the pattern size becomes very large requiring high processing power
Solution Approach 1:
The patent divides the code into two separate components: a regular pattern providing coarse position information and a pseudo-random code providing fine position information. This segmentation allows each component to have optimized properties - the regular pattern can be large and simple, while the pseudo-random code is compact and provides high-resolution data without requiring the entire pattern to be at micron-level density.
Solution Approach 2:
The patent transitions from using a single two-dimensional code to using a composite structure combining a regular two-dimensional pattern with a pseudo-random code layer. This dimensional approach allows the system to extract position information from multiple spatial frequencies, achieving high precision without requiring the entire pattern to be densely encoded at micron-level resolution.
2Reliability
If error correction is added to make the system resilient to dust, then reliability is improved, but processing power requirement increases
Solution Approach 1:
The patent incorporates feedback mechanisms where the decoding process uses the known structure of the regular pattern and pseudo-random code to verify and correct reading errors. The system can detect inconsistencies caused by dust or lighting variations and correct them by referencing the expected code structure, achieving error correction without requiring complex additional hardware or excessive processing power.
3Measurement precision
If a color code is used to achieve two-dimension position measurement, then measurement precision is improved, but sensitivity to lighting conditions worsens
Solution Approach 1:
The patent changes the parameter used for encoding from color information to binary intensity information (black and white patterns). This parameter change makes the code less sensitive to lighting variations and color discrimination issues, while maintaining the ability to encode two-dimensional position data through the spatial arrangement of the binary pattern elements.
Data Source
Figure 1~3(b)
Figure 4~5
Figure 6
AI summary
The present invention discloses a two-dimension position measurement system comprising: - an object on which is applied a two-dimension absolute code interlaced with a two-dimension regular pattern, and - a camera for acquiring a portion of the two-dimension code, the two-dimension absolute code being given by bt,u+1={bt,uifαu=0bt-1,uifαu=1 with bt,0=at, and at and au being binary values of codes {at} and {au} respectively, and wherein all codewords au and at of codes {at} and {au} respectively are unique within the codes {at} and {au} respectively. The present invention also discloses a method for measuring a position of a camera with respect to an object on which the above-mentioned two-dimension code is applied, the method comprising the following step: - acquiring an image of the two-dimension code, - extracting the absolute code in the form of a two-dimension matrix bl,u, - decoding an horizontal codeword at and a vertical codeword au, - computing a precise position (X, Y, θ) of the camera.