Non-Contact Angular Position Detection Using Dot Pattern Matching
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Solution Overview
Problem
Existing position determination methods for inertial navigation systems and manufacturing assembly lines require physical contact, which is undesirable, necessitating a non-contact method to sense the angular position of objects or inertial sensor assemblies.
Innovation Solution
A method and system using a digital camera and processor to obtain and process images of objects with pseudo-random dot patterns, comparing the images to stored dot maps to form coordinate transformation matrices for determining the angular position without physical contact, applicable to both spherical and non-spherical objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical contact methods are used to determine angular position, then measurement can be achieved, but wear and damage occur
Solution Approach 1:
The patent replaces mechanical contact-based angular position measurement with an optical system. A digital camera captures images of dots on the object, and a processor determines angular position by comparing dot positions in captured images with reference images, eliminating mechanical wear entirely while maintaining measurement capability
Solution Approach 2:
The patent creates optical copies (images) of the object's surface features (dots) at different angular positions. By capturing and comparing these optical copies rather than using physical contact, the system determines angular position without wear or damage to the measured object
2Reliability
If non-contact optical methods are used, then wear is eliminated, but system complexity increases
Solution Approach 1:
The system uses a digital camera to create optical copies (images) of dot patterns on the object surface. By comparing these optical copies with reference images stored in memory, the system determines angular position without mechanical contact, achieving wear-free operation with relatively simple equipment
Solution Approach 2:
The patent introduces dot patterns as intermediary markers on the object surface. These dots serve as reference points that facilitate optical measurement, allowing the camera and processor to determine angular position by tracking dot positions rather than directly measuring the object itself
3Measurement precision
If dot pattern matching is used to determine position, then non-contact measurement is achieved, but processing time increases
Solution Approach 1:
The patent pre-generates a dot map showing expected dot positions at various angular positions and stores reference images in memory before measurement begins. During operation, the processor compares captured images against these pre-prepared references, significantly reducing processing time compared to calculating positions from scratch
Solution Approach 2:
The system focuses processing on specific local features (dot positions and patterns) rather than analyzing the entire image. By identifying and comparing only the relevant dot markers, the system achieves accurate position determination with minimal processing time
Data Source
AI summary
A method and system for determining the angular position of an object are disclosed. As one example, a method for determining the angular position of an object is disclosed, which includes the steps of obtaining data representing an image of a surface area of the object, the image including a plurality of dots, determining a set of coordinates for each dot of the plurality of dots, selecting a predetermined number of dots of the plurality of dots, comparing the predetermined number of dots with a plurality of dots stored in a dot map, responsive to the comparing step, if the predetermined number of dots substantially match the plurality of dots stored in the dot map, selecting the predetermined number of dots, and forming a coordinate transformation matrix representing a transformation from a coordinate frame associated with a position of the predetermined number of dots at the surface of the object to a coordinate frame associated with a position of the image of the surface area of the object.