speech recognition demo in python

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@5659 d0543943-73ff-0310-b7d9-9358b9ac24b2
This commit is contained in:
Traun Leyden 2007-08-22 14:23:28 +00:00
parent 88bbc489d1
commit b3454792b1
3 changed files with 286 additions and 0 deletions

View File

@ -0,0 +1 @@
# empty

View File

@ -0,0 +1,198 @@
from freeswitch import *
from xml.dom import minidom
VOICE_ENGINE = "cepstral"
VOICE = "William"
"""
A few classes that make it easier to write speech applications
using Python. It is roughly modelled after the equivalent that
is written in JavaScript.
Status: should work, but not yet complete. some pending items
are mentioned in comments
"""
class Grammar:
def __init__(self, name, path, obj_path,
min_score=1, confirm_score=400, halt=False):
"""
@param name - name of grammar to reference it later
@param path - path to xml grammar file
@param obj_path - xml path to find interpretation from root
in result xml, eg, 'interpretation'
@param min_score - score threshold to accept result
@param confirm_score - if score below this threshold, ask user
if they are sure this is correct
@param halt - not sure what was used for in js, currently unused
"""
self.name=name
self.path=path
self.obj_path=obj_path
self.min_score=min_score
self.confirm_score=confirm_score
self.halt=halt
class SpeechDetect:
def __init__(self, session, module_name, ip_addr):
self.session=session
self.module_name=module_name
self.ip_addr=ip_addr
self.grammars = {}
def addGrammar(self, grammar):
self.grammars[grammar.name]=grammar
def setGrammar(self, name):
self.grammar = self.grammars[name]
def detectSpeech(self):
# TODO: we might not always want to call detect_speech
# with this cmd, see js version for other options
# also see detect_speech_function() in mod_dptools.c
cmd = "%s %s %s %s" % (self.module_name,
self.grammar.name,
self.grammar.path,
self.ip_addr)
console_log("debug", "calling detect_speech with: %s\n" % cmd)
self.session.execute("detect_speech", cmd)
console_log("debug", "finished calling detect_speech\n")
class SpeechObtainer:
def __init__(self, speech_detect, required_phrases, wait_time, max_tries):
"""
@param speech_detect - the speech detect object, which holds a
reference to underlying session and can
be re-used by many SpeechObtainers
@param required_phrases - the number of required phrases from the
grammar. for example if its prompting for
the toppings on a sandwhich and min toppings
is 3, use 3. normally will be 1.
@param wait_time - the time, in millisconds, to wait for
input during each loop iteration
@param max_tries - this number multiplied by wait time gives the
'total wait time' before we give up and return
partial or no result
"""
self.speech_detect=speech_detect
self.required_phrases=required_phrases
self.wait_time=wait_time
self.max_tries=max_tries
self.detected_phrases = []
def setGrammar(self, grammar):
"""
@param grammar - instance of grammar class
"""
self.grammar=grammar
self.speech_detect.addGrammar(grammar)
self.speech_detect.setGrammar(self.grammar.name)
def detectSpeech(self):
self.speech_detect.detectSpeech()
def run(self):
"""
start speech detection with the current grammar,
and listen for results from asr engine. once a result
has been returned, return it to caller
"""
def dtmf_handler(input, itype, funcargs):
console_log("INFO","\n\nDTMF itype: %s\n" % itype)
if itype == 1: # TODO!! use names for comparison instead of number
return self.handle_event(input, funcargs)
elif itype== 0:
console_log("INFO","\n\nDTMF input: %s\n" % input)
else:
console_log("INFO","\n\nUnknown input type: %s\n" % itype)
return None
num_tries = 0
session = self.speech_detect.session
console_log("debug", "setting dtmf callback\n")
session.setDTMFCallback(dtmf_handler, "")
console_log("debug", "calling getDigits\n")
console_log("debug", "starting run() while loop\n")
while (session.ready() and
num_tries < self.max_tries and
len(self.detected_phrases) < self.required_phrases):
console_log("debug", "top of run() while loop\n")
session.collectDigits(self.wait_time)
num_tries += 1
console_log("debug", "while loop finished\n")
return self.detected_phrases
def handle_event(self, event, funcargs):
"""
when the dtmf handler receives an event, it calls back
this method. event is a dictionary with subdictionaries ..
Example 1
=========
{'body': None, 'headers': {'Speech-Type': 'begin-speaking'}}
Example 2
=========
{'body': '<result xmlns='http://www.ietf.org/xml/ns/mrcpv2'
xmlns:ex='http://www.example.com/example' score='100'
grammar='session:request1@form-level.store'><interpretation>
<input mode='speech'>waffles</input></interpretation></result>',
'headers': {'Speech-Type': 'detected-speech'}}
This dictionary is constructed in run_dtmf_callback() in
freeswitch_python.cpp
"""
# what kind of event?
headers = event['headers']
speech_type = headers['Speech-Type']
if speech_type == "begin-speaking":
# not sure what to do with this, try returning "stop"
# so that it might stop playing a sound file once
# speech has been detected
return "stop"
elif speech_type == "detected-speech":
# extract the detected phrase. from result
# BUG: this assumes only ONE interpretation in the xml
# result. rest will get igored
# NOTE: have to wrap everything with str() (at least
# calls to console_log because otherwise it chokes on
# unicode strings.
# TODO: check the score
body = event['body']
dom = minidom.parseString(body)
phrase = dom.getElementsByTagName(self.grammar.obj_path)[0]
phrase_text = self.getText(phrase)
if phrase_text:
self.detected_phrases.append(str(phrase_text))
# do we want to return stop? what should we return?
return "stop"
else:
raise Exception("Unknown speech event: %s" % speech_type)
def getText(self, elt):
""" given an element, get its text. if there is more than
one text node child, just append all the text together.
"""
result = ""
children = elt.childNodes
for child in children:
if child.nodeType == child.TEXT_NODE:
result += str(child.nodeValue)
return result

87
scripts/recipewizard.py Normal file
View File

@ -0,0 +1,87 @@
from freeswitch import *
from py_modules.speechtools import Grammar, SpeechDetect
from py_modules.speechtools import SpeechObtainer
import time, os
VOICE_ENGINE = "cepstral"
VOICE = "William"
GRAMMAR_ROOT = "/usr/src/freeswitch_trunk/scripts"
"""
Example speech recognition application in python.
How to make this work:
* Get mod_openmrcp working along with an MRCP asr server
* Add /usr/src/freeswitch/scripts or equivalent to your PYTHONPATH
* Restart freeswitch
* Create $GRAMMAR_ROOT/mainmenu.xml from contents in mainmenu() comments
"""
class RecipeWizard:
def __init__(self, session):
self.session=session
self.session.set_tts_parms(VOICE_ENGINE, VOICE)
self.main()
def main(self):
console_log("debug", "recipe wizard main()\n")
self.speechdetect = SpeechDetect(self.session, "openmrcp", "127.0.0.1");
self.speechobtainer = SpeechObtainer(speech_detect=self.speechdetect,
required_phrases=1,
wait_time=5000,
max_tries=3)
gfile = os.path.join(GRAMMAR_ROOT, "mainmenu.xml")
self.grammar = Grammar("mainmenu", gfile,"input",80,90)
self.speechobtainer.setGrammar(self.grammar);
console_log("debug", "calling speechobtainer.run()\n")
self.speechobtainer.detectSpeech()
self.session.speak("Hello. Welcome to the recipe wizard. Drinks or food?")
result = self.speechobtainer.run()
console_log("debug", "speechobtainer.run() result: %s\n" % result)
if result:
self.session.speak("Received result. Result is: %s" % result[0])
else:
self.session.speak("Sorry, I did not hear you")
console_log("debug", "speechobtainer.run() finished\n")
def mainmenu():
"""
<!DOCTYPE grammar PUBLIC "-//W3C//DTD GRAMMAR 1.0//EN"
"http://www.w3.org/TR/speech-grammar/grammar.dtd">
<grammar xmlns="http://www.w3.org/2001/06/grammar" xml:lang="en"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.w3.org/2001/06/grammar
http://www.w3.org/TR/speech-grammar/grammar.xsd"
version="1.0" mode="voice" root="root">
<rule id="root" scope="public">
<rule id="main">
<one-of>
<item weight="10">drinks</item>
<item weight="2">food</item>
</one-of>
</rule>
</rule>
</grammar>
"""
pass
def handler(uuid):
session = PySession(uuid)
session.answer()
rw = RecipeWizard(session)
session.hangup("1")