Embedded Calibration Target for Automated Data Readers
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Solution Overview
Problem
Existing automated data reading systems face challenges in accurately calibrating extrinsic parameters due to bulky calibration targets that introduce operational and systemic errors, such as imprecise positioning and complex setup processes, which can skew calibration-control points and interfere with the decode process.
Innovation Solution
A planar calibration target is coupled to the automated data reading system, with spaced-apart optical codes at predetermined locations on a surface to define known calibration-control points, allowing for the calibration of extrinsic parameters based on differences between known and observed locations, and a freestanding template with calibration codes on opposing sides for multi-plane calibration, enabling precise calibration of multiple imaging systems around the read zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bulky calibration target is used for geometric camera calibration, then the calibration process can be performed with known geometric properties, but the target introduces positioning errors and interferes with the decode process
Solution Approach 1:
The patent extracts the calibration function from a physical bulky target and embeds it directly into the housing structure of the automated data reading system. Calibration control points are integrated into the housing at predetermined locations, eliminating the need for external calibration targets and their associated positioning errors.
Solution Approach 2:
The calibration control points are pre-positioned on the housing during manufacturing, establishing known reference locations before the actual calibration process. This preliminary positioning eliminates the need for manual target placement and ensures consistent, accurate calibration references.
2Measurement precision
If a planar calibration target is used instead of bulky targets, then positioning accuracy improves, but the target still requires complex setup and may interfere with normal operation
Solution Approach 1:
The patent merges the calibration target functionality with the housing structure itself. The housing serves dual purposes: as the physical enclosure for the imaging system and as the calibration reference frame. This integration eliminates separate setup steps and reduces operational complexity.
Solution Approach 2:
The system performs self-calibration by using its own housing structure as the calibration reference. The imaging system automatically references the calibration control points embedded in its housing, eliminating the need for external operators to set up and manage separate calibration targets.
3Measurement precision
If calibration control points are placed on external targets, then known locations can be established, but the targets interfere with the decode process during normal operation
Solution Approach 1:
The patent applies different properties to different locations on the housing. Calibration control points are placed in specific locations on the housing that are optimized for calibration purposes, while the main reading zone remains clear for normal decode operations. This spatial differentiation allows both functions to coexist without interference.
4Measurement precision
If multiple imaging systems are calibrated using separate calibration targets, then each system can be calibrated independently, but the process becomes time-consuming and error-prone
Solution Approach 1:
The housing structure serves as a universal calibration reference for multiple imaging systems simultaneously. All imaging systems mounted on the housing reference the same embedded calibration control points, allowing concurrent calibration of multiple systems without requiring separate targets or sequential processing.
Data Source
AI summary
Calibrating extrinsic parameters of an imaging system in an automated data reading system includes obtaining, from the imaging system, image data representing an imaged portion of a planar calibration target. The target is coupled to a housing of the automated data reading system and superimposed on a surface thereof. For example, the calibration target is placed on a conveyer surface, or it is printed on the housing of the automated data reading system. The imaged portion of the planar calibration target includes spaced-apart optical codes disposed at positions that coincide with predetermined locations of the automated data reading system to define known calibration-control points for the surface. Optical codes represented in the image data are decoded to obtain observed calibration-control points used for calibrating the extrinsic parameters based on differences between the known and observed locations of the calibration-control points.