swirec_word_beam
Threshold to control the number of paths considered. swirec_word_beam is analogous to swirec_state_beam, except that swirec_state_beam prunes paths that are within a word, whereas swirec_word_beam prunes only at word boundaries.
Value |
Float: -100–100. As many as three values are allowed. A typical range is between -60 and 0. DEFAULT: 0, -15, -35 |
How to set |
Shown in precedence order (see Rules of parameter precedence): Set in the browser, using the Vendor-Specific-Parameters header in a RECOGNIZE method. In the application's session xml in the <speechrecog> section of <sessionparameters> |
Usage |
This is an advanced feature for developers who are familiar with Recognizer and its underlying models. It can be used to trade off accuracy and CPU usage according to the needs of the application. |
Performance |
Changing the default value can seriously impair accuracy or lead to an increase in CPU usage. After changing the value, you must thoroughly test recognition accuracy and CPU usage before applying the change to a production system. |
A higher value allows consideration of more paths (that is, it prunes fewer paths). This tends to improve accuracy at the expense of higher computation. You can use it when you need higher accuracy or lower CPU usage.
swirec_state_beam is more “powerful” than swirec_word_beam, because it prunes many more paths. But sometimes it is advantageous (that is, from an accuracy standpoint) to prune only at word boundaries.
Often they are tuned together (when increasing one, you increase the other).
Browsers usually set this parameter in a RECOGNIZE request, and the parameter automatically reverts to the previous value after the recognition event. (Alternatively, browsers can use the SET-PARAMS method. See Configuring Recognizer with the browser.)
Vendor-Specific-Parameters: swirec_word_beam=0 -15 -35
Sample definition in a grammar file:
<meta name="swirec_word_beam" content="0 -15 -35"/>
Sample definition in the <speechrecog> section of a session.xml file:
<param name="swirec_word_beam">
<value>0</value>
<value>-15</value>
<value>-35</value>
</param>
Related parameter