Reverse Vending Machine Imaging Module for Reflective Barcode Reading

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Reverse vending machines face challenges in accurately reading barcodes on shiny, dented, and reflective surfaces due to specular reflections, which existing technologies like polarized light struggle to overcome effectively, leading to inefficiencies and errors in container authentication and sorting.

Innovation Solution

The implementation of an imaging and light source module with angled light sources and multiple cameras positioned around the chamber, where light is directed to minimize specular reflections and maximize scattered light for better imaging, combined with overlapping camera fields of view to handle dented objects and varied object sizes, and adjustable illumination schemes to reduce distortion and enhance feature recognition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If polarized light is used to read barcodes on reflective surfaces, then some improvement in reading capability is achieved, but specular reflections still cause significant errors and failures

Engineering Contradiction:
Improvebarcode reading accuracyVSAvoidreading reliability on shiny surfaces
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the illumination parameters by using multiple light sources positioned at different angles (including oblique and grazing angles) rather than relying solely on polarized light. This parameter change allows the system to capture images under varying lighting conditions, enabling successful barcode reading on reflective surfaces where single-angle illumination fails.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent divides the imaging function into multiple camera units, each positioned at different angles around the chamber. This segmentation allows simultaneous capture of the same object from multiple perspectives, ensuring that at least one camera can read the barcode successfully despite specular reflections affecting certain angles.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple cameras are positioned around the chamber to handle dented objects and varied sizes, then object recognition accuracy improves, but device complexity increases

Engineering Contradiction:
Improvefeature recognition accuracyVSAvoidimaging system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent designs the imaging and light source module as a universal, multi-functional unit that can handle diverse container types (different materials, shapes, sizes, and conditions) through a standardized configuration. Each module contains multiple cameras and light sources that work together to provide both imaging and illumination functions, reducing the need for separate specialized systems for different container types.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements a modular design where imaging and light source modules can be nested or arranged in arrays around the chamber. This nesting approach allows the system to scale from simple to complex configurations based on needs, while maintaining a compact structure where modules can be positioned at different radial distances and angles.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Measurement precision

If light sources are positioned to minimize specular reflections, then imaging quality on shiny surfaces improves, but the configuration becomes more complex

Engineering Contradiction:
Improveimaging quality on reflective surfacesVSAvoidlight source configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by positioning light sources at specific locations with specific angular relationships to the camera axes. Each light source is optimized for its local position, with oblique or grazing angle illumination designed to minimize specular reflections from particular surface orientations. This localized optimization across multiple positions achieves superior overall imaging quality without requiring a single complex adjustable system.

Inventive Principle:
Principle #3Local quality

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 configuration significantly improves the accuracy of barcode reading and feature recognition on challenging surfaces, reducing errors and enhancing the machine's ability to handle diverse container types, including shiny and dented items, while maintaining a compact and reliable design.

Implementation Method 1

wherein the one camera and the one light source are oriented such that light from the light source illuminates the object with an angle minimizing specular reflections and maximizing scattered light

Methodology Applied
Scientific EffectSpecular reflection: Reflection

Implementation Method 2

light from the light source illuminates the object with an angle minimizing specular reflections and maximizing scattered light

Methodology Applied
Scientific EffectScattered light: Scattering

Data Source

PatentEP3477606B1System and method for reading features in reverse vending machines
Publication Date: 2024.07.24 TOMRA SYSTEMS
  • EP3477606B1 patent drawingFigure 1
  • EP3477606B1 patent drawingFigure 2
  • EP3477606B1 patent drawingFigure 3

AI summary

A reverse vending machine comprising a plurality of light sources and a plurality of 2D imaging devices, wherein the plurality of 2D imaging devices and the plurality of light sources are arranged as a plurality of imaging and light units (40) around the perimeter of the chamber (20), each of said imaging and light units (40) comprises one 2D imaging device (41) and one light source (42) viewing and illuminating the object oblique angles, wherein the reverse vending machine is provided with a transparent or translucent layer (45) positioned in front of the imaging and light units (40), with the imaging and light units (40) of a first side of the layer (5) and the location where the object is situated when being viewed and illuminated on a second side of the layer, opposite the first side. Also, an imaging and light source module for a reverse vending machine.