July 20, 2005Microsoft Tablet PC Microsoft’s Cursive Recognizer Jay Pittman and the entire Microsoft Handwriting Recognition Research and Development Team

July 20, 2005Microsoft Tablet PC The Handwriting Recognition Team  An experiment:  A research group, but not housed in MSR  Positioned inside a product group  Our direction and inspiration come directly from the users  This isn’t for everyone, but we like it  Just over a dozen researchers  Half with PhDs  Mostly CS, but 1 Chemistry, 1 Industrial Engineering, 1 Math, 1 Speech  Mostly neural network researchers Small to moderate experience in other recognition technologies

July 20, 2005Microsoft Tablet PC Neural Network Review  Directed acyclic graph  Nodes and arcs, each containing a simple value  Nodes contain activations, arcs contain weights  At run-time, we do a “forward pass” which computes activation from inputs to hiddens, and then to outputs  From the outside, the application only sees the input nodes and output nodes  Node values (in and out) range from 0.0 to

July 20, 2005Microsoft Tablet PC TDNN: Time Delayed Neural Network item 2item 3item 1 item 5 item 6 item 4 item 1  This is still a normal back-propagation network  All the points in the previous slide still apply  The difference is in the connections  Connections are limited  Weights are shared  The input is segmented, and the same features are computed for each segment  Small detail: edge effects  For the first two and last two columns, the hidden nodes and input nodes that reach outside the range of our input receive zero activations

July 20, 2005Microsoft Tablet PC Training  We use back-propagation training  We collect millions of words of ink data from thousands of writers  Young and old, male and female, left handed and right handed  Natural text, newspaper text, URLs, addresses, street addresses  We collect in nearly two dozen languages around the world  Training on such large databases takes weeks  We constantly worry about how well our data reflect our customers  Their writing styles  Their text content  We can be no better than the quality of our training sets  And that goes for our test sets too

July 20, 2005Microsoft Tablet PC Languages  We ship now in:  English (US), English (UK), French, German, Spanish, Italian  We have done some initial work in:  Dutch, Portuguese, Swedish, Danish, Norwegian, Finnish  We cannot predict when we might ship these  Are starting initial research in more  Using a completely different approach, we also ship now in:  Japanese, Chinese (Simplified), Chinese (Traditional), Korean

July 20, 2005Microsoft Tablet PC Recognizer Architecture … … … Output Matrix dog68 clog57 dug51 doom42 divvy37 ooze35 cloy34 doxy29 client22 dozy13 Ink Segments Top 10 List d 92 a 88 b 23 c 86 o 77 a 73 l 76 t 5 g 68 t 8 b 6 o 65 g 57 t 12 TDNN a b d o g a b t t c l o g t Lexicon e a … … … … … Beam Search a b d e g h n o

July 20, 2005Microsoft Tablet PC Language Model  We get better recognition if we bias our interpretation of the output matrix with a language model  Better recognition means we can handle sloppier cursive  You can write faster, in a more relaxed manner  The lexicon (system dictionary) is the main part  But there is also a user dictionary  And there are regular expressions for things like dates and currency amounts  We want a generator  We ask it: “what characters could be next after this prefix?”  It answers with a set of characters  We still output the top letter recognitions  In case you are writing a word out-of-dictionary  You will have to write more neatly

July 20, 2005Microsoft Tablet PC Clumsy lexicon Issue  The lexicon includes all the words in the spellchecker  The spellchecker includes obscenities  Otherwise they would get marked as misspelled  But people get upset if these words are offered as corrections for other misspellings  So the spellchecker marks them as “restricted”  We live in an apparently stochastic world  We will throw up 6 theories about what you were trying to write  If your ink is near an obscene word, we might include that  Dilemma:  We want to recognizer your obscene word when you write it Otherwise we are censoring, which is NOT our place  We DON’T want to offer these outputs when you don’t write them  Solution (weak):  We took these words out of the lexicon  You can still write them, because you can write out-of-dictionary  But you have to write very neat cursive, or nice handprint  Only works at the word level  Can’t remove words with dual meanings  Can’t handle phrases that are obscene when the individual words are not

July 20, 2005Microsoft Tablet PC Regular Expressions  Many built-in, callable by ISVs, web pages  Number, date, time, currency amount, phone number, address, URL, address, file name, phrase list  Many components of the above: Month, day of month, day of week, year, area code, hour, minute  Isolated characters: Digit, lowercase letter, uppercase letter  None: Yields an out-of-dictionary-only system (turns off the language model)  Great for form-filling apps and web pages  Accuracy is greatly improved  This is in addition to the ability to load the user dictionary  One could load 500 color names for a color field in a form-based app  Or 8000 drug names in a prescription app  The regular expression compiler is available at run time  Software vendors can add their own regular expressions  One could imagine the DMV adding automobile VINs  Example expressions (from the built-in date format):  digit = " ";  nummonth = ["0"] " " | "1" "012";  numday = ["0"] " " | "12" digit | "3" "01";  numyear = [ "12" digit ] digit digit ;  numyear = "'" digit digit;  numdate = nummonth "/" numday ["/" [ "12" digit ] digit digit];  numdate = nummonth "-" numday ["-" [ "12" digit ] digit digit];

July 20, 2005Microsoft Tablet PC Default Factoid  Used when no factoid is set  Intended for natural text, such as the body of an  Includes system dictionary, user dictionary, hyphenation rule, number grammar, web address grammar  All wrapped by optional leading punctuation and trailing punctuation  Hyphenation rule allows sequence of dictionary words with hyphens between  Alternatively, can be a single character (any character supported by the system) Leading Punc Number Hyphenation UserDict SysDict Trailing Punc Web Single Char StartFinal

July 20, 2005Microsoft Tablet PC Error Correction: SetTextContext() Dictum Left Context Right Context “Dict” “” d 100 a 0 b 0 c 0 i 100 e 0 t 100 n 5 c 100 a 0 i 85 a 57 o User writes “Dictionary” 2. Recognizer misrecognizes it as “Dictum” 3. User selects “um” and rewrites “ionary” 4. TIP notes partial word selection, puts recognizer into correction mode with left and right context 5. Beam search artificially recognizes left context 6. Beam search runs ink as normal 7. Beam search artificially recognizes right context 8. This produces “ionary” in top 10 list; TIP must insert this to the right of “Dict” Goal: Better context usage for error correction scenarios

July 20, 2005Microsoft Tablet PC Calligrapher  The Russian recognition company Paragraph sold itself to SGI (Silicon Graphics, Incorporated), who then sold it to Vadem, who sold it to Microsoft.  In the purchase we obtained:  Calligrapher Cursive recognizer that shipped on the first Apple Newton (but not the second)  Transcriber Handwriting app for handheld computers (shipped on PocketPC)  Calligrapher has a very similar architecture Instead of a TDNN it employs a hand-built HMM The lexicon and beam search similar in nature (many small differences)  We combined our system with Calligrapher  We use a voting system (neural nets) to combine each recognizer’s top 10 list  They are very different, and make different mistakes  We get the best of both worlds  If either recognizer outputs a single-character “word” we forget these lists and run the isolated character recognizer

July 20, 2005Microsoft Tablet PC Personalization  Ink shape personalization  Simple concept: just do same training on this customer’s ink Start with components already trained on massive database of ink samples Train further on specific user’s ink samples  Explicit training User must go to a wizard and copy a short script Do have labels from customer Limited in quantity, because of tediousness  Implicit training Data is collected in the background during normal use Doesn’t have labels from customer We must assume correctness of our recognition result using our confidence measure We get more data  Much of the work is in the infrastructure: GUI, database, management of different user’s trained networks, etc.  Lexicon personalization: Harvesting  Simple concept: just add the user’s new words to the lexicon  Examples (at Microsoft): RTM, dev, SDET, dogfooding, KKOMO, featurization  Happens when correcting words in the TIP  Also scan Word docs and outgoing (avoid spam)

July 20, 2005Microsoft Tablet PC Best Job at Microsoft  Bill Gates makes more money, but I have more fun  No one hassles me for money or slots  I remember senior people at several research institutions saying “waste of time and money”  Insert here  I still have a sense of wonder that it works at all  It’s as if your dog starting talking to you  People tell me it recognizes their writing when no one else can  But I also know there are others who get poor recognition  I wonder if Gary Trudeau has tried it  People will adapt to a recognizer, if they use it enough  Just as they adapt to the people they live with and work with  My physician in Issaquah gets perfect recognition on a Newton  Biggest complaint: we don’t yet ship their language  Other complaints:  Weak on URLs, addresses, slashes  Some handprint gets poor recognition  Adaptation to my handwriting style (coming)