Spectroscopic interferometer: Larger measurement range using wavelet threshold denoising and adaptive peak extraction

We propose a spectroscopic interferometer measurement range enlargement method, which expands the measurement range of the existing spectroscopic interferometer. The proposed method includes wavelet arc threshold denoising and adaptive peak extraction. The wavelet arc threshold denoising, which is composed of wavelet decomposition, wavelet arc threshold processing and wavelet reconstruction, is designed to enhance the signal-to-noise ratio. The wavelet arc threshold proposed can calculate by the high-frequency wavelet coefficients, internal and external tuning parameter, which makes the selection of the threshold more flexible. The adaptive peak extraction is developed to search peaks by crest width threshold and average crest height. We construct an experimental setup and implement a series of experiments. The result of the experiments indicate that the proposed method can expand the measuring range of the spectroscopic interferometer up to 4.6305 mm. •A spectroscopic interferometer measurement range enlargement method is proposed. A wavelet arc threshold denoising is developed to enhance the signal-to-noise ratio.•The wavelet arc threshold is proposed to calculate by the use high-frequency wavelet coefficients, internal and external tuning parameter, which makes the selection of the threshold more flexible.•The adaptive peak extraction is designed to search peaks by crest width threshold and average crest height.•The proposed scheme can expand the measuring range of the spectroscopic interferometer up to 4.6305 mm.