Fig. 1. The distribution with the original data and middle 99% data

Fig. 2. Spike removal of 1-dimensional spectra with different window size and threshold
a: Raw spectrum; b: Spike removal with window size 7, threshold 1×10^-5; c: Spike removal with window size 3, threshold 1×10^-5; d: Spike removal with window size 7, threshold 1×10^-3; e: Spike removal with window size 3, threshold 1×10^-3. Arbitrary offsets were applied on the spectra for better visualization

Fig. 3. 1-dimensional Raman spectra spike removal process
a: Raw Raman spectrum; b: Raman Spectrum after 1-dimensional spike removal. Arbitrary offsets were applied on the spectra for better visualization

Fig. 4. 1-dimensional spectrum with artificial spikes
(a): Raman spectrum after spike removal; (b): Raman spectrum with 0.1 times artificial spikes;(c): Raman spectrum with 0.2 times artificial spikes; (d): Raman spectrum with 0.3 times artificial spikes; (e): Raman spectrum with 0.4 times artificial spikes; (f): Raman spectrum with 0.5 times artificial spikes

Fig. 5. 2-dimensional Raman image spike removal process
(a): Raw Raman image; (b): Raman image after 2-dimensional spike removal

Fig. 6. 3-dimensional Raman data cube spike removal process
(a): Raw Raman data cube; (b): Raman data cube after 3-dimensional spike removal

Table 1. Flowchart of algorithm

Table 2. 1-dimensional Raman spectra spike detection

Table 3. 2-dimensional Raman image spike detection

Table 4. 3-dimensional Raman data cube spike detection