Cased Goods Inspection Using Diffused Light Sheets
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Solution Overview
Problem
Current cased goods inspection systems face challenges in achieving high speed, resolution, robustness, and cost-effectiveness, particularly in differentiating between shrink wrap and opaque cardboard, and in accurately measuring dimensions of products with complex shapes and translucent packaging.
Innovation Solution
A cased goods inspection system that uses a combination of light sources and cameras to capture orthographic projections, with image analysis algorithms that account for light intensity variations and debris detection, enabling precise measurement of 'real box', 'max box', 'max bulge', and orientation angle, while rejecting or accepting products based on allowable dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LED curtain lighting is used for inspection, then the system can detect material presence, but the LEDs have considerable spacing between them (>5mm) so they only produce a 'sampled' image instead of imaging the cased goods completely
Solution Approach 1:
The patent introduces a diffuser as an intermediary component between the LED light sources and the inspection target. The diffuser breaks up the sampled light pattern into a continuous illumination sheet, enabling complete imaging of the cased goods while maintaining the simplicity of LED architecture. This resolves the contradiction by mediating between the spaced LED sources and the requirement for continuous illumination.
2Measurement precision
If LED light curtains are used, then the system can detect material presence in its path, but they are unable to differentiate a piece of shrink wrap from an opaque cardboard piece
Solution Approach 1:
The patent transitions from one-dimensional material detection (presence/absence in light path) to two-dimensional imaging by using a diffuser to create a light sheet that illuminates the entire surface of cased goods. This enables the system to capture spatial information and differentiate between translucent shrink wrap and opaque cardboard based on light transmission patterns across the illuminated surface.
3Speed
If laser triangulation method is used, then the approach is fast, precise and robust, but it is sensitive to reflective surfaces like shrink wraps and cannot differentiate a piece of shrink wrap from cardboard
Solution Approach 1:
The patent uses a diffuser as an intermediary to convert directional laser light into a scattered light sheet pattern. This diffused illumination reduces sensitivity to reflective surfaces by distributing light across multiple angles, allowing the system to maintain fast inspection speeds while improving reliability on translucent and reflective packaging materials.
4Measurement precision
If a vision system is used to inspect cased goods, then the system can obtain measurements, but incident light intensity variations cause false product detection and false measurements
Solution Approach 1:
The patent employs a diffuser to create uniform light distribution across the inspection area, establishing equipotential illumination conditions. This ensures consistent light intensity across the entire field of view, eliminating false detections caused by varying incident light conditions while maintaining measurement precision.
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
The system provides accurate and reliable inspection of products with complex shapes and translucent packaging, reducing false detection and measurement errors, and effectively differentiates between shrink wrap and opaque materials, enhancing measurement accuracy and operational robustness.
Implementation Method 1
camera subsystem configured to capture orthographic projections
Implementation Method 2
differentiate a piece of shrink wrap from an opaque cardboard piece
Data Source
AI summary
A method of inspecting cased goods includes advancing at least one case of goods on a conveyor, generating an illumination sheet of parallel illuminating rays with at least one electromagnetic source, and capturing an image, formed by the illumination sheet passing through a diffuser with at least one camera located so as to capture illumination from diffused parallel rays of the light sheet, where the image case embodies a goods image that is generated by the case goods moving between the light source and the at least one camera, where part of the parallel sheet of light is at least partially blocked by the case of goods, thus generating a gray level image.