Sensor Electrode Modulation to Restore Mean Signals and Reduce Blur

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Solution Overview

Problem

Existing sensors face challenges in accurately detecting objects due to carrier cancellation, electrical coupling between electrodes leading to blurring in reconstructed digital images, and the need to restore common mode portions of signals for improved image quality.

Innovation Solution

A system and method involving modulation and demodulation patterns are applied to electrode groups to remove the mean value from received signals, with a global restore value added to compensate for the removed mean, and interleaved electrode arrangements to minimize electrical coupling and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If carrier cancellation is applied to improve dynamic range and detection accuracy, then the ability to detect modulations is improved, but the common mode portion of the signal is lost and requires restoration

Engineering Contradiction:
Improvedetection accuracyVSAvoidcommon mode signal loss
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The system performs preliminary modulation of received signals before demodulation, using modulation patterns that preserve the common mode portion. This preliminary action allows the system to maintain information that would otherwise be lost during carrier cancellation, enabling both high detection accuracy and common mode signal preservation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback mechanisms to restore the common mode portion of the signal after demodulation. By analyzing the demodulated values and applying appropriate restoration based on the modulation patterns used, the system recovers the common mode signal that was temporarily removed during processing, ensuring complete signal information is retained.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If adjacent electrodes are placed close together to increase sensor resolution, then detection precision is improved, but electrical coupling between electrodes causes blurring in reconstructed images

Engineering Contradiction:
Improvesensor resolutionVSAvoidelectrical coupling blurring
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system segments the electrode array into distinct groups with specific modulation patterns applied to each group. This segmentation allows independent processing of signals from different electrode groups, reducing the impact of electrical coupling between adjacent electrodes. By treating electrode groups separately through modulation and demodulation, the system maintains high spatial resolution while minimizing blurring effects.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the electrical parameters of electrode groups by applying different modulation patterns to different groups. This parameter change allows the system to distinguish between signals from adjacent electrodes even when electrical coupling occurs, as the modulation patterns create distinct signal characteristics that can be separated during demodulation, thereby reducing blurring while maintaining close electrode spacing.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3841518B1Systems and methods for improving image quality in sensors
Publication Date: 2026.02.18 IDEX BIOMETRICS ASA
  • EP3841518B1 patent drawingFigure 1
  • EP3841518B1 patent drawingFigure 2
  • EP3841518B1 patent drawingFigure 3A

AI summary

Systems and methods for detecting a user's finger or other elements may be provided. In some embodiments, a system may include a plurality of electrode groups, and each electrode group may include a respective reference electrode for which a true signal value is a predetermined value. In some embodiments, the system may process signals received by the electrode groups by: (a) modulating the signals received from each electrode of the respective electrode group according to a modulation pattern; (b) demodulating the signals, or values derived therefrom, received from each electrode of the respective electrode group according to a demodulation pattern, thereby determining a set of demodulated values for the respective electrode group; and/or (c) using the predetermined value for the reference electrode of the respective electrode group, restoring a mean value to the signals, or values derived therefrom, received from each electrode of the respective electrode group.