Hello everyone,<br><br>This is the status update of the GSoC project, Speech Recognition facility in Openmoko. This week, much of the time was devoted in writing codes and optimizing the existing one. I have written many subroutines like forward backward procedure, LPC and cepstral analysis of speech signals in frames, viterbi algorithm and training algorithm using K-means segmental method. All the source codes have been successfully compiled using GNU C compiler. <br>
There are various optimizations done in the coding to make it suitable for working on the ARM 16/32-bit processor running at 266 or 400 MHz maximum. The whole code is written using fixed point arithmetic. I used some external libraries for some subroutines and converted them in fixed point arithmetic. The other optimization was done by choosing K-means segmental procedure for training the HMM models rather than Baum Welch algorithm which requires more processing since it accounts for all the possible hidden states for a given sequence. On the other hand K-means segmental method uses viterbi algorithm to find the best state sequence and then iterates for re-estimation and training the HMM model. K-means segmental method has been proved to show good results and fast processing than Baum-Welch. The other optimization is regarding the probability density function. As this project aims for a small vocabulary (around 5 or 10) for recognition, vector quantization will be used instead of continuous observation sequence. Vector quantization procedure is faster and yields good result for applications in small embedded devices. The vector quantization source code is about to finish. Soon after that, the actual testing of speech recognition code will be done on the speech samples collected. <br>
I have uploaded all Documents (Design Document version-0.2) and source codes on the svn repository of Openmoko (<a href="https://svn.projects.openmoko.org/svnroot/speech/">https://svn.projects.openmoko.org/svnroot/speech/</a>). Any comments and suggestions will be highly appreciated.<br>
<br><a href="http://saurabh1403.wordpress.com/">http://saurabh1403.wordpress.com/</a><br><br>Regards....<br>-- <br>Saurabh Gupta<br>Electronics and Communication Engg.<br>NSIT,New Delhi<br><br>