Image Processing Apparatus Self-Calibration Without Calibration Board
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Solution Overview
Problem
Existing image processing apparatuses for acquiring three-dimensional shapes of measuring objects require complex calibration processes, including the use of calibration boards, to associate world coordinates with illumination device coordinates, increasing user burden and installation complexity.
Innovation Solution
An image processing apparatus with a unique illumination housing design featuring four light projecting sections that emit diffused light and generate pattern lights from different directions, allowing for the estimation of camera parameters without a calibration board by capturing pattern image sets and relative position information, enabling direct association of world coordinates with imaging device coordinates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pattern projection method is used with separate world coordinate and illumination coordinate, then measurement capability is achieved, but calibration using calibration board is required which increases installation complexity and user burden
Solution Approach 1:
The patent merges the illumination coordinate system and camera coordinate system into a unified coordinate system. The illumination device includes four light projecting sections that project pattern lights from different directions, and the coordinate systems are integrated such that no separate calibration is needed. The relative positions of light projecting sections are predetermined, allowing direct association of measurement coordinates with camera coordinates.
Solution Approach 2:
The system performs self-calibration by using the predetermined relative positions of the four light projecting sections within the illumination device. The calibration information is embedded in the device structure itself, eliminating the need for external calibration boards or manual calibration procedures. The system automatically associates world coordinates with camera coordinates through the integrated coordinate system design.
2Measurement precision
If relative position between imaging device and illumination device must be determined in advance, then measurement accuracy is improved, but user burden during installation is increased
Solution Approach 1:
The relative positions of the four light projecting sections are predetermined and fixed during manufacturing. This preliminary determination of spatial relationships eliminates the need for users to manually determine relative positions during installation. The integrated coordinate system is pre-configured with the correct geometric relationships between illumination and camera components.
Solution Approach 2:
By integrating the illumination device and camera into a single coordinated system with unified coordinate transformation, the patent eliminates the need for separate relative position determination. The four light projecting sections and camera share a common coordinate reference frame, allowing accurate measurement without manual alignment or position determination by the user.
3Measurement precision
If calibration board is used to associate world coordinate with illumination coordinate, then coordinate association accuracy is improved, but calibration process becomes cumbersome
Solution Approach 1:
The illumination device performs self-calibration through its integrated coordinate system design. The four light projecting sections are positioned with predetermined relative positions that are encoded in the device structure. This self-contained calibration capability eliminates the need for external calibration boards, manual measurement, and complex calibration procedures.
Solution Approach 2:
The patent introduces an intermediary coordinate transformation system that directly links world coordinates with camera coordinates through the integrated illumination and camera system. This intermediary coordinate association mechanism, based on the predetermined geometry of the four light projecting sections, eliminates the need for calibration boards and simplifies the coordinate association process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces the complexity of installation and calibration by eliminating the need for calibration boards, allowing for accurate measurement of three-dimensional shapes without the need for complex relative position determination, thereby enhancing user convenience and measurement reliability.
Implementation Method 1
a first light source that emits diffused light and a first pattern light generating section which receives the diffused light emitted from the first light source and generates a plurality of first measurement pattern lights
Implementation Method 2
an imaging device which receives the first measurement pattern light reflected from the measuring object to generate a plurality of first pattern image sets
Data Source
AI summary
To make it possible to associate a world coordinate with a coordinate of an imaging device without using a calibration board. A plurality of pattern images are generated by receiving measurement pattern light reflected from a measuring object. X coordinate, Y coordinate, and Z coordinate of a specific point are measured based on a plurality of pattern images, and a calibration target is generated from measurement result of the X coordinate, Y coordinate, and Z coordinate. Calibration is executed using the generated calibration target.