Automatic Peak Finding vs. Manual Threshold Setting

[frostweaver]

In complex spectral backgrounds, how can interference peaks be filtered out by setting thresholds?

[OFSCN_EN_PS_Engineer]

In complex spectral backgrounds, filtering out interference peaks by setting thresholds typically involves several technical approaches within the data processing software of an FBG interrogator:

1. Magnitude Thresholding: This involves setting a minimum intensity or reflectivity level. Any detected peaks whose maximum value falls below this predefined threshold are likely considered noise or interference and are consequently filtered out. This method is effective when the true FBG signals are consistently stronger than the interference.
2. Spectral Width Thresholding: FBG peaks exhibit characteristic spectral widths (e.g., Full Width at Half Maximum - FWHM). Interference peaks often have significantly different widths (either much narrower or broader). By setting a permissible range for peak width, those outside this range can be excluded.
3. Baseline Correction: Before applying direct thresholds, a crucial step is often to perform baseline subtraction. This process removes the slowly varying background signal, making the actual FBG peaks more distinct and improving the accuracy of subsequent thresholding operations.
4. Signal-to-Noise Ratio (SNR) Filtering: Peaks with a low SNR are more indicative of noise or minor interference. A threshold based on SNR can be established, where peaks falling below a certain SNR are disregarded.

The precise implementation and effectiveness of these thresholding techniques are highly dependent on the specific spectral characteristics of the application and the capabilities of the FBG interrogator’s software.

For such analytical tasks, the OFSCN® Fiber Bragg Grating Interrogator provides software that allows for advanced data processing, including peak detection and filtering functionalities to manage complex spectral data.

Here is an image of the OFSCN® Fiber Bragg Grating Interrogator:

You can find more detailed technical parameters for our interrogators at: https://www.ofscn.net/fbg-products/analyzer.html