Frequency-Division Magnetic Localization for Capsule Endoscopy
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Solution Overview
Problem
Current capsule endoscopy technologies face challenges in precisely localizing an ingestible pill within the digestive tract, leading to inaccurate monitoring and diagnosis of digestive tract issues, as existing localization schemes are either imprecise or require high power consumption.
Innovation Solution
A frequency-division multiplexing-based magnetic localization (FDMML) approach that uses multiple external magnetic beacons with different offset frequencies to generate magnetic fields, allowing the ingestible pill to accurately track its position using a low-power, high-sensitivity receiver and neural network processing, achieving sub-millimeter precision and real-time 3D tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional magnetic localization methods are used, then localization can be achieved, but power consumption is high and precision is insufficient
Solution Approach 1:
The patent divides the localization system into multiple magnetic beacons distributed throughout the digestive tract, each operating at a different offset frequency. This segmentation allows the system to achieve high precision localization through multiple measurement points while distributing the power consumption across multiple low-power beacon units rather than requiring a single high-power system.
Solution Approach 2:
The patent introduces frequency as an additional dimension for signal differentiation. By assigning unique offset frequencies to each magnetic beacon, the system can simultaneously operate multiple beacons without interference, enabling precise 3D localization through frequency-division multiplexing while maintaining low power consumption through efficient spectral utilization.
2Productivity
If multiple magnetic beacons are excited concurrently, then localization speed is improved, but signal interference increases
Solution Approach 1:
The patent segments the frequency spectrum by assigning unique offset frequencies to each magnetic beacon. This frequency division allows multiple beacons to operate concurrently without mutual interference, enabling parallel measurement and significantly improving localization speed while maintaining clean signal separation through spectral filtering.
Solution Approach 2:
The patent uses frequency offset as an intermediary mechanism to distinguish between signals from different magnetic beacons. The receiver differentiates beacon signals based on their unique offset frequencies, allowing concurrent operation without interference and enabling rapid multi-point localization through frequency-division multiplexing.
3Force
If high-power excitation is used, then magnetic field strength increases, but power consumption increases
Solution Approach 1:
The patent utilizes frequency as an additional dimension for signal transmission. By operating magnetic beacons at different offset frequencies rather than increasing power, the system achieves sufficient magnetic field strength for localization while maintaining low power consumption. The frequency differentiation allows multiple beacons to operate simultaneously at low power levels.
Solution Approach 2:
The patent changes the operating parameter from power magnitude to frequency offset. Instead of increasing excitation power to strengthen magnetic fields, the system uses frequency modulation and offset differentiation to enable multiple beacons to operate concurrently at low power levels, achieving both sufficient field strength and low power consumption through parameter transformation.
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 FDMML method provides sub-millimeter 3D localization accuracy, significantly reduces power consumption, and enables faster tracking, making it suitable for wearable systems and clinical applications by concurrently exciting multiple magnetic beacons and using high-Q resonant coils with sustained current.
Implementation Method 1
all external magnetic beacons (MBs) are concurrently excited, each having a different small (e.g., 1 Hz-1 MHz range) offset frequency from the carrier (e.g., 1-100 MHz range)
Implementation Method 2
The FDMML pill receiver amplifies the voltage picked up by a resonant RX coil from the fields produced by all the MBs
Implementation Method 3
The FDMML pill receiver amplifies the voltage picked up by a resonant RX coil from the fields produced by all the MBs
Data Source
AI summary
Disclosed herein are systems and methods related to a capsule endoscopy, where a patient can swallow an ingestible capsule that records images of digestive tract, and a new in-body positioning system can precisely localize the capsule's position. Implementations include a new frequency-division multiplexing-based magnetic localization (FDMML) approach which leverages a higher frequency carrier in the low MHz range. The approach significantly reduces the reference excitation coil sizes and decreases the required excitation current by three orders of magnitude compared to prior work, making it practical for wearable systems. A fully integrated wireless receiver prototype is implemented in 180 nm bulk CMOS and packaged in an ingestible pill form factor. The new scheme achieves the best experimentally demonstrated tracking accuracy in both 2D and 3D localization experiments, achieving a sub-mm mean absolute position error and consuming only 247 pW while running at 100% duty cycle.