3D Position Measurement Using Ray Information Storage
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Solution Overview
Problem
Existing position measurement techniques using omnidirectional cameras require complex optical calculations and stored camera parameters, leading to inaccuracies when an acrylic hemispherical dome is attached, which complicates the calculation of refractive indices and results in large errors in position measurement.
Innovation Solution
A position measuring apparatus that uses ray information storage and processing units to associate ray vectors with pixels in input images, allowing for three-dimensional position measurement without relying on internal camera parameters, enabling precise position measurement and distortion correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex optical calculations are performed using stored camera parameters, then position measurement can be achieved, but measurement precision deteriorates when an acrylic hemispherical dome is attached due to inability to exactly calculate refractive index
Solution Approach 1:
The patent creates a virtual camera that copies the optical characteristics of the physical camera system including the acrylic dome. By storing ray information that represents the actual light paths through the dome, the system avoids complex real-time optical calculations while maintaining measurement precision. The virtual camera model replicates the refractive effects without requiring explicit refractive index calculations.
Solution Approach 2:
The patent performs preliminary calibration to generate and store ray information before actual position measurement. During calibration, the system pre-calculates and stores the relationship between pixel coordinates and ray directions for various viewing angles. This preliminary action eliminates the need for complex optical calculations during runtime, as the ray information is readily available from pre-computed data.
2Ease of operation
If parameters stored inside the camera are used for position measurement, then measurement process is simplified, but measurement precision deteriorates due to inaccuracies in calculating refractive index through the acrylic dome
Solution Approach 1:
The patent introduces ray information as an intermediary between the camera parameters and the position measurement process. Instead of directly using stored camera parameters that require complex optical calculations, the system uses pre-computed ray information that directly represents light paths. This intermediary simplifies the measurement operation while maintaining precision, as the ray information already accounts for the acrylic dome's refractive effects.
3Measurement precision
If complex optical calculations are required, then accurate corresponding points can be obtained, but the measurement process becomes difficult to implement when refractive index cannot be exactly calculated
Solution Approach 1:
The patent creates a virtual camera model that copies the optical behavior of the physical system. By storing ray information that represents actual light paths through the acrylic dome, the system achieves accurate corresponding point detection without requiring explicit optical calculations. The virtual camera model replicates the refractive effects, making the system easy to implement while maintaining precision.
Solution Approach 2:
The patent performs preliminary calibration to generate ray information tables that map pixel coordinates to ray directions. This pre-computed data is stored and reused during position measurement, eliminating the need for complex real-time optical calculations. The preliminary action makes the system easy to implement while ensuring accurate corresponding point detection.
Data Source
AI summary
A position measuring apparatus which measures a position of a position measurement target easily and accurately without using any parameter inside a camera in the measurement, based on images captured from mutually different viewpoints. The position measuring apparatus which measures the three-dimensional position of the position measurement target, based on the input images captured from the mutually different viewpoints, and the position measuring apparatus includes: a ray information storage unit configured to store ray information in which each of ray vectors is associated with a corresponding one of pixels in one of the input images, each of the ray vectors indicating a forward direction of a light incident onto an optical system for a corresponding one of the input images; and a position measuring unit configured to measure the three-dimensional position of the position measurement target, using the ray information stored in the ray information storage unit.