.KEYWORD automic
.FLYINGHEAD PRODUCT REVIEW
.TITLE A better microphone for Auto PC
.FEATURE
.SUMMARY Recently, Andrea Electronics has developed a microphone for the Auto PC that effectively gives the Auto PC four "ears" and the ability to focus on a single speaker. Will it vastly improve Auto PC speech recognition? You’ll have to read Mark Moeller’s article to find out.
.AUTHOR Mark Moeller
One of the cornerstone features of the Auto PC is its speech driven user interface. In an effort to reduce distraction to the operator of the vehicle and to keep the operator’s hands on the wheel and eyes on the road, speech recognition seems a natural answer. Speech is the only open ended method of "output" that the driver of the car has left.
The ideal speech user interface would allow you to talk to your Auto PC just as you would talk to any passenger in your car. Theoretically, it would understand you as well (or better) than some passengers would. There are many reasons that this technology simply doesn’t exist today. Yes, you will see some pretty amazing demos of speech recognition systems with natural language parsing on the back end, but these are primarily research projects running on very powerful and expensive CPUs.
One of the biggest stumbling blocks to a successful speech recognition user interface is simply identifying who or what the computer should be listening to. The microphone that comes with the Auto PC is a simple single element, wide pickup device. All incoming audio gets treated equally and it’s left for the speech recognition engine to sort out speech from the incoming cacophony of sound. In a noisy environment, this is difficult at best, but usually impossible.
Compare this with the auditory system that people have. Our two ears feed processed signals to the most powerful computing device known to mankind, the brain. The brain then does some non-trivial signal processing, measuring the arrival time of a given sound to each of the ears. Correlating the incoming signals and presenting the hearer with an array of sounds, we can then individually focus on each and know where the sound originates in three dimensions. This is obviously oversimplified, but illustrates the advantage our auditory system has over a single microphone. If you enjoy experiments, try identifying where three individual speakers are located at with respect to each other when listening to a recording of their speech as they are all talking.
Recently, a company by the name of Andrea Electronics has developed a microphone for the Auto PC that effectively gives the Auto PC four "ears" and the ability to focus on a single speaker.
.H1 Andrea AutoArray DA-300
The product is called the Andrea AutoArray DA-300 and it’s made specifically for the Auto PC. This microphone, shown in Figure A, replaces the stock "mouse style" microphone that ships with Clarion’s AutoPC 310C. It is a phased array microphone that is specifically designed for enhancing speech recognition in an automobile. This microphone operates as four separate microphone elements, which run their signals into a digital signal processor. The signal processor then adaptively focuses the microphone on the driver’s voice and rejects other noise.
.FIG A The AutoArray microphone is a long device that might best be attached to your sun visor.
Andrea reports that the microphone will give a 93 percent or better recognition accuracy rate in a driving environment that has a certain noise level. Meanwhile, the current Clarion AutoPC microphone can’t recognize anything at the same noise level. While I have no way to validate this number, my experience using the microphone leaves me believing their conclusions.
.H1 Installation
The AutoArray is comprised of two primary components, the Digital Signal Processor (DSP) module, shown in Figure B, with power supply and the microphone array with connector cable.
.FIG B The DSP is a simple box with a lot of special-purpose computing power.
Installation is really pretty simple as far as hooking up the hardware goes. With the Auto PC powered off, you simply unplug the standard Auto PC microphone from the rear of the Auto PC, and plug the AutoArray DSP module into the now empty microphone jack. The DSP module must be wired to a switched 12V power supply. You should be able to connect this module’s positive power lead into the Accessory switch input lead on the Auto PC and connect its ground lead to the ground lead of the Auto PC. Once that’s done, you plug the microphone array into the DSP module. It uses a simple RJ-type connector that’s slightly larger than the connector on a CAT5 network cable. If you typically don’t do any wiring in your car, have a professional do the installation.
.CALLOUT If you typically don’t do any wiring in your car, have a professional do the installation.
With the AutoArray now connected, you should power up the Auto PC and give the microphone a test. You should see a steady green light on the face of the microphone indicating that it is powered up. Keep the microphone face twelve inches or so away from your face and say "Auto PC". The Auto PC should promptly respond, awaiting your next command word. Once you have verified that the AutoArray is working correctly, you can use the double-sided tape or spring clips to install the AutoArray on the visor of the driver. Fasten down the DSP module and tie or tuck the wires securely. Check Andrea Electronics’ installation instructions for complete installation information.
.H1 Operation
There really isn’t anything that you do with the AutoArray besides speak. Don’t speak at it, let it find you and keep your eyes on the road. The AutoArray will find you in three dimensional space much like the human auditory system would. It then focuses and tracks your voice, feeding a very clear signal of your voice to the Auto PC. The Auto PC speech recognition software really seems to like the AutoArray. Given that the signal is so clear, its recognizer takes less time to recognize your speech.
.H1 Performance
I tried creating a variety of ambient noise conditions. Only in the noisiest cases, I couldn’t get the AutoArray to pick out my voice. By noisiest cases I mean having the radio volume cranked so loud that it was painful to listen to (even then it would pick out my voice if I spoke louder). Under even moderately loud volume conditions, I rarely had to raise my voice to get the Auto PC to recognize me. Under these same volume conditions, I would have to yell to get the Auto PC to recognize me using the standard microphone.
If you are a talk radio listener like myself, you’ve probably had the Auto PC wake up to some random word that someone on the radio says. If not, you’ve probably experienced the Auto PC simply never recognizing you if you are playing the radio at any sort of high volume level. The AutoArray fixes this problem marvelously. It’s able to pick out your voice alone and pass it along to the Auto PC.
Another area that AutoArray should excel in, although I didn’t get to test it, is dramatically improving recognition accuracy in SUV’s and convertibles. These high road noise environments have been a great source of frustration for Auto PC users because the noise would confuse the recognizer or drown out the driver’s voice.
Since the AutoArray is able to focus in on the user’s voice, users who are soft spoken or have a higher pitched voice will benefit greatly from this microphone. Ambient noise in the vehicle makes speech recognition notoriously difficult for a person with these attributes and in some cases unworkable. The AutoArray will put an end to these difficulties. I enjoyed the fact that it was able to pick my voice out when I spoke softer to my Auto PC. With the standard microphone, I always have to raise my voice to get my Auto PC to hear me. Not so with the AutoArray.
.H1 Where do I get one?
I’m going to purchase an AutoArray for my Auto PC. It made my speech-based interaction with the Auto PC a far less frustrating and stressful experience. Simply not having to shout to get the Auto PC’s attention was perhaps the biggest appeal to me, but also the increased recognition accuracy and improved recognition speed were a welcome benefit as well. This product is available for purchase now from authorized Auto PC dealers. I’m told it sells for around $150, seemingly steep but the improvement is worth it. You can check out this unit on Andrea’s web site at http://www.andreaelectronics.com/dsda.htm.
.BEGIN_SIDEBAR
.H1 Product availability and resources
The new Andrea AutoArray microphone for the Auto PC is available at http://www.andreaelectronics.com/dsda.htm.
.END_SIDEBAR
.BIO
