Softnet Systems, Inc. Speech Recognition Specialists

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Accuracy

There are many different factors involved in accuracy, and many different "tricks" to improving it. Sometimes it takes a while to discover the root problems.

Acoustic Optimizer

Like performing more General Training, results after running Acoustic Optimizer vary. Because it has a history of corrupting speech files, we strongly suggest creating a backup voice folder prior to running the Acoustic Optimizer.

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Capitalization Problems

If running in "Unsupported Applications" where the checkmark on the DragonBar is not green, capitalization will not be perfect. The Nuance advice is to use the Dictation Box in these areas.

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Extraneous Word Errors

Extraneous words may be introduced into a document. Typically these are small words which get inserted when you are not speaking.

  • If the word appears even though you said nothing, then check the position of your microphone and make sure it is out of your "breath stream" you make when you speak. Keeping your microphone about a ½ inch away from your mouth, off to the side, either a little above or below your mouth. The "magic" position is different for each person and microphone. Once you have found this position, try always to put it in the same place.
  • If the word repeats itself (e.g. "him him him ..." or "it it it ...." then it is likely either interference or a microphone issue.
  • Make sure that your computer is not making noises or that the noise is not in the room. All types of equipment can make noise that can be misinterpreted as a small word. If you suspect your computer is making noises, but you can't actually hear them try making a recording to listen to. Dictate then use one of the "Playback" commands to listen to the sound input.
  • Keyboard noises sometimes introduce words. Certain types of microphones may be more prone to do this than others. Position of the microphone is very significant for noises generated very close to the microphone such as keyboard noise. You may have to "play" with the microphone position, or obtain a quiet keyboard. Ironically, "noise-cancelling" microphones may not be much better than other microphones for cancelling keyboard noises.
  • Record yourself or play back your speech and see if the noises persist. While doing this, wiggle the microphone cable as a bad connector or frayed wire within the microphone can cause this symptom.
  • Sometimes a correction has inadvertently corrupted the voice file, making Dragon think that a particular sound corresponds to a word. Train the word and the word within a short phrase.
  • Create a new user profile and see if the same problem exists. If not, then it is possible that the speech files have gotten corrupted. This may be due to a correction you made, a bug, an unfortunate computer glitch, etc.

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Hardware

Microphones, sound cards, etc. can cause errors. This is particularly true on older laptop systems where components are crowded. Listen to your system! Listen to the playback to determine if clean sound is getting to the system.

With laptops, sometimes accuracy is much better running off battery than off of the A/C. That is due to interference from the AC-DC converter, a common problem. Using a USB adapter with your microphone will often resolve this problem.

Be consistent with your microphone. Do a recording, moving your microphone while you speak. With most microphones, you'll notice differences in sound levels and clarity of the sound.

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Little Word Errors

With NaturallySpeaking, it is common to have problems with little, single-syllable words. They will typically have a lower accuracy than longer words; plus, they occur more often in normal language.

The first step to take is to make corrections using PHRASES including the little words along with other words. Correct using the word before and/or after the little word that has a problem.

Some hints to solve these problems:

  • If the word appears even though you thought you said nothing, then check the position of your microphone and make sure it is out of your "breath stream" you make when you speak. We suggest keeping your microphone about a ½-inch away from your mouth, off to the side, either a little above or below your mouth. The "magic" position is different for each person and microphone. Once you have found this position, try always to put it in the same place.
  • Make sure that your computer is not actually making noises or that the noise is not in the room. All types of equipment can make noise that can be misinterpreted as a small word. If you suspect that your computer is making noises, but you can't actually hear them try making a recording to listen to. You can use the NatSpeak Sound Recorder by clicking on Tools then Sound Recorder in the NatSpeak window. You could also use one of the "Playback" commands to listen to the sound input.
  • Keyboard noises sometimes introduce words. Certain types of microphones may be more prone to do this than others. Position of the microphone is very significant for noises generated very close to the microphone such as keyboard noise. You may have to "play" with the microphone position, or obtain a quiet keyboard. Ironically, "noise-cancelling" microphones may not be much better than other microphones for cancelling keyboard noises.
  • Record yourself or play back your speech and make certain that you clearly say the little words. While doing this, wiggle the microphone cable as a bad connector within the microphone can cause this symptom. Listen for extra sounds that you may be producing.
  • Introducing phrases can help in recognition of small words, as can correcting phrases (vs. individual words). You should usually correct small words as part of a phrase rather than individually. Correcting small words individually may hurt accuracy more than it helps.
  • If the word consistently comes out wrong, and the "wrong" word is not one you use, consider adding an entry in the Vocabulary Editor for the word, with a spoken form being the word that wrongly appears. This is only useful when the word that wrongly appears is rare in your language.
  • Some words get pronounced differently when they are part of a phrase. For instance, most people only make one "m" sound when they say "skim milk." If it makes sense to do so, create short phrases using Vocabulary Editor (Vocabulary, View/Edit) that include the word giving problems. For instance, "year" is sometimes confused with "ear". Add phrases "right ear" and "left ear" to try to reduce the error rate. You can add a phrase "right ear" with a spoken form of "right year" to further resolve this problem.
  • One cause for the insertion of extra small words into your dictation, or the incorrect splitting of larger words into smaller words, is the "Pause between phrases" option being too short. From the NatSpeak Tools menu, choose Options, then select the Miscellaneous tab. The default pause setting is 250 milliseconds. This may need to be adjusted to be shorter for faster response. If you are seeing the above-mentioned problem, try lengthening the "Pause between phrases" setting.

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Performing More Training

Intuitively, doing more General Training, reading more passages, would seem to improve accuracy. This doesn't seem to always work, and in fact there is evidence that it may make matters worse. So before doing more General Training, export your user files so you have a backup. If it helps, fine. If not, back up to your earlier user files.

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Persistent Recognition Errors After Excellent Recognition

There are persistent reports from users who have had excellent recognition, then suddenly the accuracy deteriorates.

There are at least two major causes for this.

  1. Microphone failures. Try a 2nd microphone, listen to a recording of your speech, or otherwise test the microphone. Wiggle the cables while speaking -- loose connections are the major reason for microphone failure.
  2. "Corrupted" speech files. This is probably a broad category of problems, all with the same solution: Restore an earlier version of your speech files!

    Restoring speech files can be done in a number of ways. One is to use the Dragon "Restore" function which is shown on the Advanced button within Manage User Profiles, which may work if you catch the problem before Dragon saves a copy of the corrupted files. A second is to use Windows utilities to restore the files.

    If you don't have a good backup, then you must create a new user if you don't already have one.

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Wrong/Questionable Vocabulary

Sometimes, particularly with the Medical or Legal products, the wrong vocabulary is chosen. More often, a specialist decides that they need the "large" vocabulary when in fact the "medium" or "small" vocabulary will be more accurate. If you are able to analyze a substantial group of your documents, the "medium" vocabularies are likely going to be more accurate. There are a few professions such as journalism where this might not be true, as a few people dictate about a wide range of subjects.

Vocabulary preparation is another matter -- using Vocabulary Builder, VocTools, establishing custom words for acronyms, etc. is all part of getting set up for Dragon. Using your prior documents with Vocabulary Builder is important.

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