CN and Oracle Path from Lattice

[Andreas Stolcke]

Anoop Deoras wrote:
> On Dec 16, 2008, at 12:15 PM, Anoop Deoras wrote:
>
>> Hello,
>>
>>   Could someone please help me with my following questions:
>>
>> Q1. Is there a way to get Confusion Networks from Lattices such that 
>> the confusion bins are restricted
>>       between node $i$ and $i+1$ for any $i$. I am using IBM's 
>> recognizer and it has Lidia Mangu's CN generation
>>       tool incorporated. The recognizer generates CN from lattices in 
>> the fashion I described above.
>>       However when I use write-mesh command, I dont see a similar 
>> representation ? Am I missing something
>>       here ?
The "mesh" output format has lines of the form

align 1 *DELETE* 0.398704 i'm 0.178572 uh 0.135939 oh 0.0958802 i 
0.0772781 we're 0.0662928 aw 0.0473337

That is a list of the word s and their posterior probabilities between 
node 1 and node 2 (i and i+1 in general).
So is this not exactly what you want in a confusion network ?
>>
>> Q2. If I have access to true utterance and the lattice generated by 
>> the recognizer, is there a way to find out
>>       the Oracle path from this lattice ?
Not easily.  However, if you use the -reference option is used you will 
find the alignment of the reference words in the mesh output.
Andreas

>>
>>
>> Thank you in advance,
>> Regards
>> Anoop