## 14.5.1 Introduction

HARK provides static feature extraction modules such as MSLSExtraction and MFCCExtraction . HARK also provides following additional feature extraction modules and preprocessing modules:

1. Dynamic feature (Delta term): The temporal change of the static features. Notated as $\Delta$MSLS in Tab. 14.12. Calculated by Delta .

2. Power: The power of the input signal. Notated as Power in Tab. 14.12. Calculated by PowerCalcForMap .

3. Delta power: The temporal change of power. Notated as $\Delta$Power in Tab. 14.12. Calculated by Delta

4. Preprocessing: Emphasizing of the high frequency range using PreEmphasis or mean normalization. Notated as Preprocessing in Tab. 14.12.

We provide six sample networks of acoustic feature extraction as shown in Tab. 14.12. From the left, the three columns of the table denotes: the network file name, the feature description, and the feature file name generated by the network file. You can run the samples by executing demo.sh. For example, if you want to execute demo1.n, run

> ./demo.sh 1


The samples calculate the features using the MSLS of 13 dimensions in offline. If you want to calculate features in online, replace AudioStreamFromWave with AudioStreamFromMic . If you want to use MFCC instead of MSLS, replace MSLSExtraction with MFCCExtraction . If you want to change the dimension of the MSLS, change the property. See HARK document for details.

Table 14.12: Sample files of feature extraction
 Feature Network MSLS $\Delta$ MSLS Power $\Delta$Power Preprocessing Corresponding Generated file file name 13 dim 13 dim 1 dim 1 dim no dim section demo1.n Yes MFBANK13_0.spec demo2.n Yes Yes MFBANK26_0.spec demo3.n Yes Yes MFBANK14_0.spec demo4.n Yes Yes Yes Yes MFBANK28_0.spec demo5.n Yes Yes Yes MFBANK27_0.spec demo6.n Yes Yes Yes Yes MFBANK27p_0.spec