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Measurement of the Directional Information Flow in fNIRS-Hyperscanning Data using the Partial Wavelet Transform Coherence Method
Published on: September 3, 2021
Wavelet-modified maximum average correlation height filter for rotation invariance that uses chirp encoding in a
Shilpi Goyal1, Naveen K Nishchal, Vinod K Beri
1Photonics Division, Instruments Research and Development Establishment, Raipur, Dehradun 248008, India.
Applied Optics
|June 30, 2006
Summary
This study introduces a wavelet-modified maximum average correlation height (MACH) filter for robust 360-degree in-plane rotation identification in optical correlators. The new filter enhances accuracy and simplifies target detection by focusing correlation signals.
Area of Science:
- Optical Engineering
- Signal Processing
- Image Recognition
Background:
- Maximum Average Correlation Height (MACH) filters are essential for pattern recognition.
- Handling in-plane rotations in optical correlators presents significant challenges.
- Existing methods may require numerous filters for full rotational coverage.
Purpose of the Study:
- To implement a wavelet-modified MACH filter for 0-360 degree in-plane rotation identification.
- To improve the performance and reduce filter complexity in hybrid digital-optical correlators.
- To enhance autocorrelation peak intensity and signal-to-noise ratio.
Main Methods:
- A wavelet transform was integrated with the MACH filter design.
- A hybrid digital-optical correlator architecture was utilized.
- A chirp function was employed to focus correlation signals in distinct planes.
Main Results:
- The wavelet-modified MACH filter significantly enhances autocorrelation peak intensity.
- The number of required filters for full rotation detection is reduced.
- Correlation signals are successfully focused, allowing isolation of a single autocorrelation peak using a CCD camera.
Conclusions:
- The proposed wavelet-modified MACH filter offers improved performance for rotation-invariant pattern recognition.
- This approach simplifies target identification in hybrid digital-optical correlators.
- Signal-to-noise ratio serves as an effective metric for evaluating filter performance.
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