Magnetic Pattern Decoding via Noise Subtraction
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Solution Overview
Problem
Existing devices for reading magnetic characters on documents, such as cheques, face challenges due to low magnetic field signals and electromagnetic noise from internal and external sources, which complicates the reading process and increases costs with the need for shielding.
Innovation Solution
A device with a dual-reader system, where a first reader captures magnetic signals and a second reader captures noise signals, allowing for algebraic subtraction to enhance the signal-to-noise ratio, eliminating the need for shielding components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If shielding components are installed to protect from electromagnetic noise, then noise protection is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the noise signal from the composite signal by using a second reader that specifically captures electromagnetic noise. This separated noise signal is then subtracted from the first reader's output, effectively removing the harmful noise component without requiring physical shielding structures.
Solution Approach 2:
The patent converts the harmful electromagnetic noise into a useful component by capturing it with the second reader and using it for subtraction. The noise, which was previously a detrimental interference, becomes a known quantity that can be mathematically removed from the signal, transforming a problem into a solution.
2Object-affected harmful factors
If shielding components are installed to protect from electromagnetic noise, then noise protection is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the noise signal from the composite signal by using a second reader that specifically captures electromagnetic noise. This separated noise signal is then subtracted from the first reader's output, effectively removing the harmful noise component without requiring physical shielding structures.
Solution Approach 2:
The patent replaces expensive physical shielding materials with a computational approach using additional reader components. The solution uses software-based signal processing (subtraction) instead of hardware-based shielding, significantly reducing material costs and manufacturing complexity.
3Device complexity
If a single reader is used to read magnetic signals, then device complexity is reduced, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent segments the signal acquisition function into two specialized readers: the first reader captures the magnetic signal from the document, while the second reader captures the electromagnetic noise. This segmentation allows each reader to be optimized for its specific function, with the noise reader providing a clean reference signal for subtraction.
Solution Approach 2:
The patent introduces an intermediary computational process (signal subtraction) that combines the outputs of two readers. The second reader acts as an intermediary that provides the noise component, which is then mathematically removed from the first reader's signal, resulting in a high-quality cleaned signal.
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 results in a high-quality signal with improved reliability and reduced costs by eliminating the need for shielding, making the reading process simpler and more effective.
Implementation Method 1
a first magnetic reader (20) with a first coil (21), connected to a first amplifier (15a), and arranged to read field magnetic signals coming from the magnetic patterns (13) and electromagnetic noise
Implementation Method 2
a second magnetic reader or a dummy magnetic reader (40), comprising a second coil (41), connected to a second amplifier (15b), and arranged to read the electromagnetic noise
Implementation Method 3
a first amplifier (15a), and arranged to read field magnetic signals coming from the magnetic patterns (13) and electromagnetic noise
Data Source
AI summary
A device for decoding magnetic patterns printed on documents comprising a reading head (12) having: a reader (20) arranged to read first magnetic signals belonging to the magnetic patterns and to electromagnetic noise due to sources internal and/or external to the device. The device further comprises: a further reader (40), arranged to read second magnetic signals belonging to the electromagnetic noise, an adder component (25) arranged to algebraically subtract the amplified second magnetic signals from the amplified first magnetic signals, and a converter (16) arranged to convert the resulting signal into a digital signal representing the read magnetic patterns. A method for decoding magnetic patterns is also disclosed.