Food Probe Impedance Sensing for Cooking Type Recognition

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Solution Overview

Problem

Existing methods for monitoring cooking processes of food stuffs, such as those disclosed in US 2006/0174775 A1 and DE 36 21 999 A1, fail to accurately recognize the type of food being cooked based on electrical impedance measurements.

Innovation Solution

The method involves detecting the electrical impedance of food at multiple frequencies, calculating the phase angle, and comparing it with a database to identify the food type, using a food probe with two electrodes to generate an electrical field within the food, and optionally using a non-conductive rod and spike for easy insertion and adaptability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electrical impedance is measured at a single frequency, then the measurement is simple, but the food type cannot be recognized

Engineering Contradiction:
Improvefood type recognition accuracyVSAvoidmeasurement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement process is segmented into multiple frequency points (at least two different frequencies). By measuring electrical impedance at multiple discrete frequency segments rather than a single frequency, the system captures the frequency-dependent characteristics of different food types, enabling accurate recognition while maintaining a relatively simple measurement approach.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The measurement is extended from a single frequency dimension to multiple frequency dimensions. By adding the frequency dimension to the impedance measurement, the system creates a multi-dimensional characteristic signature for each food type, which significantly improves recognition accuracy without requiring complex measurement hardware.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of information

If multiple frequencies are used for impedance detection, then food type recognition is enabled, but the measurement process becomes more complex

Engineering Contradiction:
Improvefood characteristic informationVSAvoidmeasurement difficulty
Core Design Contradiction:
Loss of informationVSDifficulty of detecting and measuring

Solution Approach 1:

A database of reference impedance values at multiple frequencies for various food types is prepared in advance. This preliminary action creates a lookup reference that simplifies the actual measurement process - instead of performing complex real-time analysis, the system measures impedance at multiple frequencies and compares the results against the pre-prepared database to identify the food type.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by comparing the measured multi-frequency impedance characteristics against a database of known food types. This feedback mechanism allows the system to iteratively identify the food type by matching the measured characteristics with the stored reference data, reducing the complexity of real-time analysis.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If a conductive rod is used for the food probe, then electrical connection is good, but safety and versatility are reduced

Engineering Contradiction:
Improveprobe versatilityVSAvoidelectrical connection reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The probe structure is segmented into separate functional components: a non-conductive rod for insertion and positioning, and separate electrodes for electrical measurement. This segmentation allows the rod to be universally compatible with different food types (improving adaptability) while the electrodes maintain reliable electrical connections for impedance measurement (maintaining reliability).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The non-conductive rod acts as an intermediary between the user and the electrical measurement system. It provides mechanical support and positioning without interfering with the electrical measurements, enabling safe and versatile use across different food types while maintaining reliable electrical connections through the separate electrodes.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach allows for efficient recognition of food types and monitoring of cooking processes, enabling automatic cooking functions by utilizing a compact and user-friendly food probe that can be adapted for individual recipes through a teach-in function.

Implementation Method 1

the electrical impedance is measured at two or more frequencies

Methodology Applied
Scientific EffectElectrical impedance: Electrical Resistance

Implementation Method 2

the at least two electrodes arranged at the food probe allow the generation of an electrical field in the core of the food stuff

Methodology Applied
Scientific EffectElectrical field: Electric Field

Data Source

PatentEP2299261B1Use of a food probe and a method for recognising the type of a food and monitoring a cooking process of a food stuff
Publication Date: 2016.02.10 ELECTROLUX HOME PROD CORP NV
  • EP2299261B1 patent drawingFigure 1
  • EP2299261B1 patent drawingFigure 2
  • EP2299261B1 patent drawingFigure 3

AI summary

The present invention relates to a food probe (10) for invading into a food stuff (20). The food probe (10) comprises an elongated rod (12) made of a non-conductive material, a front portion of the elongated rod (12), which front portion is provided for invading into the food stuff (20), a first electrode (14) made of a conductive material and arranged at the front portion of the rod (12), and a second electrode (16) made of a conductive material and arranged at the front portion of the rod (12) in a predetermined distance from the first electrode (14). The first electrode (14) and the second electrode (16) are arranged serially along the longitudinal axis of the rod (12). A voltage can be applied between the first electrode (14) and the second electrode (16), so that an electrical field (22) is generated between and in the environment of the first electrode (14) and the second electrode. Further, the present invention relates to method for recognizing the type of a food and monitoring a cooking process of the food stuff (20) by using the food probe (10).