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What problems did you run into when trying to use the speech API? It's quite an interesting avenue for bypassing these in the future as speech recognition gets

What problems did you run into when trying to use the speech API? It's quite an interesting avenue for bypassing these in the future as speech recognition gets better. Also highly entertaining when you use Google's own service against them.

dutchbrit 14y ago
Exactly my thought, with using their own service! The thing was, is that the background noise made the API not recognise the actual words (I think - since you can't really "debug"), but maybe if you reduce the noise, it might be possible - I wanted to give that a go, but haven't had a chance yet. I just don't know of any ways to automatically reduce noise.
- deleted 14y ago
  [deleted]
- coldpie 14y ago
  I suspect you haven't gotten around to it, but did you study the noise at all? According to Wikipedia <http://en.wikipedia.org/wiki/Voice_frequency> http://en.wikipedia.org/wiki/Voice_frequency>, 85-255 Hz is the usual range of human speech. You could try a band-pass filter with that pass band, and probably a pretty high roll-off (this will cut off sounds like S and X, but I suspect voice recognition software is often capable of dealing with those, given how often they fail to be represented well in discrete audio). Audacity can do this, and there's almost certainly automatible tools out there. Worth a shot, anyway.
  - dutchbrit 14y ago
    I found Audicity when I was playing around, but I didn't get round to actually trying it. Didn't know about the frequency so thanks!!!
    - goostavos 14y ago
      The coursera Machine Learning course references an algorithm that can separate speech from noise, which a fairly high degree of accuracy. May be worth looking into. Noise removal tools like audacity tend to introduce "watery" or "bubbly" effects when pushed hard.
  - Dn_Ab 14y ago
    There must be a reason why they are confident current algorithms will have a hard time. The article says it works by playing speech backwards so any basic filter will also significantly distort the speech part since I assume the "noise" will occupy similar bands. Subtractive techniques probably won't work either because the noise will likely be highly varying. But perhaps if one could learn two sparse representations that incorporated phase information for backwards and forwards speech using matrix factorization - it might work as a method for removing recaptcha noise. This idea is so simple though, I assume someone tried it and it doesn't work well.
dutchbrit 14y ago
Ps. Here's how you send the audio to the API - the mp3 that you can download from reCaptcha needs converting to flac first, which can be achieved with ffmpeg. http://pastebin.com/LQ30iWKD http://pastebin.com/LQ30iWKD
- robotmay 14y ago
  Awesome, that's nice and straightforward. If you could improve the audio quality/remove noise, then it could make for an entertaining web service. You could go so far as making a browser plugin (for more irony; in Chrome) which would auto submit the audio file and enter the text for people.
  - dutchbrit 14y ago
    Indeed, that was my initial plan, after getting frustrated at ThemeForest.net Seriously, who adds reCaptcha to a login form?!

dutchbrit 14y ago

Exactly my thought, with using their own service! The thing was, is that the background noise made the API not recognise the actual words (I think - since you can't really "debug"), but maybe if you reduce the noise, it might be possible - I wanted to give that a go, but haven't had a chance yet. I just don't know of any ways to automatically reduce noise.

deleted 14y ago
[deleted]
coldpie 14y ago
I suspect you haven't gotten around to it, but did you study the noise at all? According to Wikipedia <http://en.wikipedia.org/wiki/Voice_frequency> http://en.wikipedia.org/wiki/Voice_frequency>, 85-255 Hz is the usual range of human speech. You could try a band-pass filter with that pass band, and probably a pretty high roll-off (this will cut off sounds like S and X, but I suspect voice recognition software is often capable of dealing with those, given how often they fail to be represented well in discrete audio). Audacity can do this, and there's almost certainly automatible tools out there. Worth a shot, anyway.
- dutchbrit 14y ago
  I found Audicity when I was playing around, but I didn't get round to actually trying it. Didn't know about the frequency so thanks!!!
  - goostavos 14y ago
    The coursera Machine Learning course references an algorithm that can separate speech from noise, which a fairly high degree of accuracy. May be worth looking into. Noise removal tools like audacity tend to introduce "watery" or "bubbly" effects when pushed hard.
- Dn_Ab 14y ago
  There must be a reason why they are confident current algorithms will have a hard time. The article says it works by playing speech backwards so any basic filter will also significantly distort the speech part since I assume the "noise" will occupy similar bands. Subtractive techniques probably won't work either because the noise will likely be highly varying. But perhaps if one could learn two sparse representations that incorporated phase information for backwards and forwards speech using matrix factorization - it might work as a method for removing recaptcha noise. This idea is so simple though, I assume someone tried it and it doesn't work well.

dutchbrit 14y ago

Ps. Here's how you send the audio to the API - the mp3 that you can download from reCaptcha needs converting to flac first, which can be achieved with ffmpeg. http://pastebin.com/LQ30iWKD http://pastebin.com/LQ30iWKD

robotmay 14y ago
Awesome, that's nice and straightforward. If you could improve the audio quality/remove noise, then it could make for an entertaining web service. You could go so far as making a browser plugin (for more irony; in Chrome) which would auto submit the audio file and enter the text for people.
- dutchbrit 14y ago
  Indeed, that was my initial plan, after getting frustrated at ThemeForest.net Seriously, who adds reCaptcha to a login form?!