Assignment 3: PG 94 col. 1593-4

In this forum, we will work with people who are training OCR engines for Polytonic Greek, helping them improve the quality of their engines by correcting specific texts.
Stephen Hughes
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Recognition of columnation

Post by Stephen Hughes » May 23rd, 2014, 12:16 pm

BruceRobertson wrote:Feel free to provide corrected Greek and leave the Latin as is. Someone else can do that.
Yes, I can do no more than correct individual letters there.

Doesn't the machine recognise columns?
Will the software mix up the Latin and Greek in an identical way every time?
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Stephen Hughes
Posts: 3323
Joined: February 26th, 2013, 7:12 am

Inconsistant diacritics

Post by Stephen Hughes » May 24th, 2014, 3:22 am

In 1593 line 49 Φαρισαῖοι appears to have either a short tilda (cf. line 46 χεῖρόν where the iota has a full tilda), or it is a mistakenly written ἴ (but cf. line 54 where ἴδε is written distinctly).

How should I treat it?
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Stephen Hughes
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Re: My tips for making the machine more intelligent

Post by Stephen Hughes » May 24th, 2014, 8:50 am

Here are my thoughts about how to make the machine think intelligently about what it has scanned, and which sections it could handle by itself, and which it could alert a human operator that assistence is required, based on that page of Greek. I honestly don't have much to say about the Latin. I decided to major in Greek and Modern Greek, not Greek and Latin like my other classmates (except the one that majored in Greek and philosophy).

Every speaker / user of a language has their own rules for the language. These are mine. These are only my reasoning for wrong words. Do you also need the reasons for confirming the validity of the correct words or are you just leaving well enough alone there?

I suppose that when a few users put their reading strategies up, the machine might be able to intelligently deal with contradictions in reasonings.
  • ἀκμοβυστίa -> ἀκροβυστίᾳ because the iota subscript is quite clear below the alpha & there is no word ἀκμοβυστία in the lexicon
  • Mωὔσέως -> Mωϋσέως because 2 acute accents don't occur in successive syllables.
  • 4λλʼ -> ἀλλʼ because a word can't start with a double lambda & ἀλλʼ is a common word.
  • Χα -> Καὶ because an unaccented word can't follow a full-stop. Καὶ is a common three-letter word to start a sentence.
  • Σαδβάτῳ -> Σαββάτῳ because the consonant cluster δβ does not occur in Greek & Σαββάτῳ is a common word.
  • ἄνθρωππον -> ἄνθρωπον because ππ never follows an ω in Greek & ἄνθρωπον is a common word.
  • Σαβθάτῳ -> Σαββάτῳ because the consonant cluster βθ does not occur in Greek & Σαββάτῳ is a common word.
  • ό -> because there is no single word ό & all initial vowels or diphthongs carry a breathing.
  • Mωβ- -> Mωϋ because the letter combination μωβ does not occur in Greek & Mωϋσέως is a common word.
  • σέωως -> Mωϋσέως because ωω is extremely rare & Mωϋσέως is a common word.
  • χολῶτε -> χολᾶτε because second person subjunctives are introduced by other words. χολῶτε is subjunctive. χολᾶτε is indicative / imperative.
  • δτι -> ὅτι because δτ never begins a word in Greek & ὅτι is permissible / common enough at the start of phrases.
  • δλον -> ὅλον because δλ doesn't usually usually start a word. The delta could be confused for an omicron with the spiritus asper.
  • ἐτοησα -> ἐποίησα **I recognise this is not a valid, but I would not have been able to easily guess this**
  • Σαβδάτῳ -> Σαββάτῳ because it is a common word in this context.
  • ὁgν -> ὄψιν **I recognise this is not a valid, but I would not have been able to easily guess this**
  • ἀLλὰ -> ἀλλὰ because L doesn't occur in Greek words & ἀλλὰ is a common word.
  • δικααν -> δικαίαν **I recognise this is not a valid, but I would not have been able to easily guess this**
  • Τν Εαββάτῳ -> τῷ Σαββάτῳ because Τν is not a valid word in Greek, nor is Εαββάτῳ. An intitial Ε needs a breathing, but there is no like that, so the initial letter is probably wrong. I only know two words words that could do are κράββατος and σάββατον, and the context here is σάββατον.
  • εριτέμνειν -> περιτέμνειν because Greek words can start with an initial vowel or diophthong without either spiritus. Without adding a letter, neither ἐριτέμν- nor ἑριτέμν- are words. In adding a letter, the only option is to add a pi.
  • ἡμέρ -> ἡμέρᾳ because ἡμέρ is not a valid word. ἤπερ both requires two changes in spiritus and accent positio and it doesn't occur at the end of a sentence.
  • ἔαββάτῳ -> Σαββάτῳ because ἔαββάτῳ looks like a word, but it is not. From context Σαββάτῳ is most likely.
  • γεo3 -> γενό- **I recognise this is not a valid, but I would not have been able to easily guess this**
  • βh -> τὸ **I recognise this is not a valid, but I would not have been able to easily guess this**
  • δλικῶς -> ὁλικῶς because Greek words do not usually begin with δλ. After removing the delta, there are only two options it could be ὁλικῶς and ὑλικῶς. **I would not be able to easily guess which one it would be here**
  • MMΤὴ κρίκετε -> Mὴ κρίνετε because MMΤὴ κρίκετε is clearly a verbal unit & MMΤὴ is clearly wrong in having 2 or more majuscule letters together. It would be a hopeful guess to take MMΤὴ as Mὴ. The Greek verb κρικοῦσθαι is deponent but this form is active. From context it would be a fair assumption that this could be κρίνετε but otherwise it would be difficult to know where to start.
  • δgν -> ὄψιν **I recognise this is not a valid, but I would not have been able to easily guess this**
  • τήν -> τὴν because τήν doesn't occur mid-sentence τὴν does.
  • κρίσι• -> κρίσιν because a high point doesn't occur one word from the end of a sentence & κρίσι is a Modern Greek form using an obselete spelling standard, not a Koine Greek form. It is clearly a form of κρίσις, and it probably accusative after the τὴν and definitely so after the κατὰ (because there has to be something in the accusative with κατὰ).
  • M1ἡ -> Μὴ **I recognise this is not a valid, but I would not have been able to easily guess this**
  • ἐμω -> ἐμοῦ out of context, I would probably assume this was a contracted form of ἐμέω "to vomit", but that is not possible directly after a παρʼ (ellided form) and is here between τὸ ... γενόμενον. ***Because παρά can take a number of cases it would be difficult to guess***
  • Εt -> Εἰ because t is English, this is clearly a mistake. it is followed by a γὰρ, so it is most likely a first word in its sentence, there is a prepositional phrase
  • δτι -> ὅτι because δτ never begins a word in Greek & ὅτι is a valid word and looks like it, if we look more clearly.
  • δλον -> ὅλον because δλ doesn't usually usually start a word. The delta could be confused for an omicron with the spiritus asper. The whole phrase now seems to repeat, so the ἐτοησα mentioned above could be suggested as ἐποίησα
  • Σαβδάτῳ -> Σαββάτῳ because Σαβδάτῳ is not a valid word and Σαββάτῳ is a common word in this context.
  • Mἡ -> Μὴ because a spiritus asper is only written on certain words in non-initial position. It is grave because it is followed by another word in the sentence.
  • κaτʼ -> κατʼ because English a doesn't appear in Greek words and alpha does.
  • δgτν -> ὄψιν **I recognise this is not a valid, but I would not have been able to easily guess this**
  • Εἰγὰρ -> Εἰ γὰρ is not a valid word, but it is composed of two valid words
  • μέροςἀνθρώπου -> μέρος ἀνθρώπου because it is not a valid word but is composed of two valid words & the τελικὸν (?final?) sigma doesn't occur in a medial position.
  • δλον -> ὅλον because δλ doesn't usually usually start a word. The delta could be confused for an omicron with the spiritus asper. The whole phrase now seems to repeat, so the ἐτοησα mentioned above could be suggested as ἐποίησα
  • ὑγιή -> ὑγιῆ because ὑγιή is not a valid form of ὑγιής & an acute accent doesn't occur before this verb
  • οἰμαι -> οἶμαι because οἰμαι has no accent, and the correct breathing is the lenis. & the last syllable is short and the second last is long. **This can't be seen from the scan and needs to be done intelligently**
  • ,δτι -> , ὅτι because the is a comma after a word in all but one case ὅ,τι & δτ can't begin a word & δ looks like ὅ.
  • θλον -> Ὅλον because there is no accent, and θλόν is not a word. **I recognise this is not a valid word, but I would not have been able to easily guess this** I'm unsure why this is omicron is written majuscule here.
  • ἄνθρωπονὑγιῆ -> ἄνθρωπον ὑγιῆ because it is not a valid word but is composed of two valid words.
  • έποίησα -> ἐποίησα because a word can't have two acute accents except third-last and last.
  • Σαδθάτῳ -> Σαββάτῳ because δθ is not a valid letter combination in Greek.
  • νεῖν -> νοεῖν **I recognise this is not a valid form, but I would not have been able to easily guess this**
  • ,δτι -> , ὅτι because the is a comma after a word in all but one case ὅ,τι & δτ can't begin a word & δ looks like ὅ.
  • θλον -> Ὅλον because there is no accent, and θλόν is not a word. **I recognise this is not a valid word, but I would not have been able to easily guess this** The initial letter of a sentenceto be written majuscule as it is here.
  • έποίησα -> ἐποίησα because a word can't have two acute accents except third-last and last. The correct accentig of εποιησα is ἐποίησα.
  • ὑγῆ -> ὑγιῆ **I recognise this is not a valid form, but I would not have been able to easily guess this**
  • κᾶν -> κἂν **I have no idea about this word's usage**
  • -> **There are so many single letter words with just an eta + diacritics, I can't ;θιψκλυ formulate a succinct rule why it would be this one here and not one of the others **
  • tἄθαι -> ἰᾶσθαι **I recognise this is not a valid form, but I would not have been able to easily guess this**
  • Οτι -> Ὅτι because this word can not have no accent & ὅτι is a common enough word & an initial letter is often written majuscule after a full-stop (period), so it is likely to be validly majuscule.
  • ἐστι -> ἔστι **I understand what this means, but, although various people have tried to explain it to me, I've never understood when to use one or the other?**
  • ησοῦς -> Ἰησοῦς because there is no breathing on the initial vowel and adding one doesn't make a valid wword, the only letter that can be added to make a valid word is Ἰ.
  • , -> . **I can't think of a succinct rule for this**
  • επεν -> εἶπεν because this word has no breathing or accent and εἶπεν is a common and valid word.
  • Τδε -> Ἲδε because td is not a valid letter combination in Greek **I recognise this is not a valid form, but I would not have been able to easily guess this**
  • γέγσνας -> γέγονας because γσν is not a valid letter combination in Greek, and while γ<vowel>ν all occur, only γέγονας makes sense.
  • λνα -> ἵνα because λνα is not a valid word in Greek & ἵνα μὴ (+ subjunctive) γέηται makes a good phrase.
  • παρέσεωςς -> παρέσεως because a double sigma can't appear in final possition in Greek & παρέσεως is a valid form.
  • νογ -> νος **I recognise this is not a valid form, but I would not have been able to easily guess this**
  • δψιν -> ὄψιν because delta is similar to omicron and the correct diacritics are ὄ.
  • dαρισαῖοι -> Φαρισαῖοι because it is not the habit in Greek to include words in a foreign script, but rather to render them into Greek. Taking away the English d, and adding a Greek consonant, the only to words that can be made in Greek are Λαρισαῖοι and Φαρισαῖοι. Contextually Φαρισαῖοι is preferrable.
  • ἀ.λλὰ -> ἀλλὰ because a double lambda can't start a word and an alpha with a spiritus lenis is not a valid word either, and combining the two invalid words produces a valid one.
  • κρίνετελΤαῦτα -> κρίνετε. Ταῦτα because a majuscule letter marks the beginniung of a word and the beginning of a sentence & κρίνετε is a valid Greek word. To separate the sentences, we could assume that λ was a full-stop (period).
  • εροσολυμιτῶν -> Ἱεροσολυμιτῶν because a Greek word cannot begin with a vowel without a breathing. The two words that can be created by adding something in front are; Ἰεροσολυμιτῶν and Ἱεροσολυμιτῶν **To tell which one, I would have to look closely at that particular part of the image.
  • ψ⁶αρισαίων -> . because footnote references occur in the Latin text, not the Greek, so this ⁶ is not ever going to be right. without the ⁶, ψαρισαίων is still not a valid word, so the psi is most probably wrong. the only to words that can be made in Greek are Λαρισαῖοι and Φαρισαῖοι. Contextually Φαρισαῖοι is preferrable.
  • οὐτός ἐστιν -> οὗτός ἐστιν because the original accent of the demonstrative is not lost
  • δν -> ὃν because the delta looks like the omicron with the spiritus asper and grave & a relative is needed for the syntax
  • ζτοῦσιν -> ζητοῦσινzeta-tau is not a valid letter combination. Adding a vowel between them is an easy choice of solution. The eta "works".
  • Καἰ -> Καὶ because it produces a valid word.
  • Τδε -> ἴδε because tau-delta is not a valid combination & iota-omicron is not a diphthong.
  • παῥῥησία -> παῥῥησίᾳ because it preceeds a verb and with the iota subscriptum it is a common adverb
  • aὐτῷ -> αὐτῷ because English a doesnt occur in Greek words
  • ἰέγτουσι. -> λέγουσι. **I recognise this is not a valid form, but I would not have been able to easily guess this**
  • οὐτός ἐστιν -> οὗτός ἐστιν vide supra
  • ἀλληθῶς -> ἀληθῶς because these OCR machines often duplicate their reading of lambdas & ἀληθῶς is a valid word.
  • ό -> omicron with an acute is not a valid word and an article is needed for the syntax here
  • ἀπτει• -> άπτει• because this is not a new word.
  • οῦ -> Τοῦ **I recognise this is not a valid form, but I would not have been able to easily guess this**
  • οὐν -> οὖν because that is the correct accentuation for this word
  • ἐτίστεισαν -> ἐπίστευσαν **I recognise this is not a valid form, but I would not have been able to easily guess this**
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Γελᾷ δ' ὁ μωρός, κἄν τι μὴ γέλοιον ᾖ
(Menander, Γνῶμαι μονόστιχοι 108)

Stephen Hughes
Posts: 3323
Joined: February 26th, 2013, 7:12 am

Re: My tips for making the machine more intelligent

Post by Stephen Hughes » May 24th, 2014, 11:59 am

Stephen Hughes wrote:
  • Mωβ- -> Mωϋ because the letter combination μωβ does not occur in Greek & Mωϋσέως is a common word.
  • σέωως -> Mωϋσέως because ωω is extremely rare & Mωϋσέως is a common word.
Sorry, I wasn't paying attention to the details of the line break. That's Mωϋ- one one line, and σέως on the next.
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BruceRobertson
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Joined: May 16th, 2014, 9:49 pm

Re: Assignment 3: PG 94 col. 1593-4

Post by BruceRobertson » May 24th, 2014, 5:36 pm

Thanks for all these questions and ideas. What you propose known as applying a 'language model' to OCR output in order to correct the output so it conforms to that model. We do have a spellcheck program that uses Levenshtein distances and a large (3million) dictionary to correct some of the sorts of things you mention.

It is much better, of course, if these errors are not be corrected, but never happen in the first place. The best way to make sure that happens is to give the OCR engine enough training. If you consider that these results were generated with about 8 pages of input, then some of these forms, especially unusual combinations of vowels and accents, might never have yet appeared in the training data, or just once. Or maybe they appeared in a slightly different way. A good number of your examples are missed spaces, for instance: in effect the character 'space' was not recognized. Well, with your training data, you've just given hundreds more instances of the character 'space', and by applying this training, the engine will get better at recognizing these. Not perfect, of course, and you might have had the experience I did where I think: "you know, the computer might be right, there really isn't much of a space there!"

So we're at the stage now where we can get better results with training. But once that maxes out, we will dehyphenate the results (so that words are complete) and apply spellcheck.

You also asked about column separation. The most important step in that is to discover and remove the inter-column letters that Migne uses for a citation scheme. With those in place, no column-finding algorithm is going to get things right. With them gone, most do. So a colleague and I wrote a paper on that problem, a poster for which is here: http://heml.mta.ca/lace/datech14. This routine allows us to store the letters' coordinates, so that we can re-introduce the citation scheme at a later time. It's not a completely solved issue, since sometimes Migne crosses the page with remaining Greek text, and that can mess up a OCR page layout analyzer, but at that point, we can hopefully split these bilingual texts by finding the dividing line between the Latin-heavy and Greek-heavy halves of the page.
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BruceRobertson
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Re: Assignment 3: PG 94 col. 1593-4

Post by BruceRobertson » May 24th, 2014, 5:45 pm

In 1593 line 49 Φαρισαῖοι
This is the correct form (with circumflex). Migne was cheap with the ink, so sometimes letters and accents are not fully inked in. This is why his volumes are black-belt OCR :-)
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Stephen Hughes
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Joined: February 26th, 2013, 7:12 am

The 'language model' for Koine Greek

Post by Stephen Hughes » May 24th, 2014, 7:13 pm

BruceRobertson wrote:What you propose [is] known as applying a 'language model' to OCR output in order to correct the output so it conforms to that model.
Is that standard 'language model' that you apply to Koine Greek a public open-source document / algorithm?
BruceRobertson wrote:a large (3million) dictionary to correct some of the sorts of things you mention

Do you mean a list of words / forms that you apply the Levenshtein distance process to? Or is it like, a list of requiring / needs / attracts - required things? E.g. κατά requires something in the accusative, a verb attracts an adverb (weaker than require), nouns in the accusative might be the object of some types of verbs or go with a preposition -- like a (syntactically aware) list?

It is apparent from proofing your OCR output that there are a few different kinds of errors there. Some are things within words themselves, others are about how words relate to each other. Your Levenshtein distance process would deal with minor problems within words. Does the dictionary deal with other things for when the sentence needs looking at?
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BruceRobertson
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Re: Assignment 3: PG 94 col. 1593-4

Post by BruceRobertson » May 25th, 2014, 7:03 pm

Do you mean a list of words / forms that you apply the Levenshtein distance process to? Or is it like, a list of requiring / needs / attracts - required things? E.g. κατά requires something in the accusative, a verb attracts an adverb (weaker than require), nouns in the accusative might be the object of some types of verbs or go with a preposition -- like a (syntactically aware) list?
Yes, it is a 'dumb' list of words, available here:
https://github.com/brobertson/rigaudon/ ... ctionaries

However, the program https://github.com/brobertson/rigaudon/ ... d_dict5.py has the place for weighting various edits, so that replacing smooth breathing with acute is weighted as more preferable than replacing smooth breathing with grave.

The model does not include syntax as you describe.

All language modeling, from spellcheck to what you describe, has a cost, though. If it were applied to a dictionary, for instance, with hyphenated stems or principal parts, it would potentially 'force' forms incorrectly. Or consider app. crit.: turning a 'wrong' form into a dictionary one there misses the entire point. If your dehyphenation routine misses a beat, and you get the second half of a word at the beginning of a line assumed to be a whole word, another kind of error in introduced. Given the relatively small size of Greek literature, moreover, for any quotation from literature for which we have a 'known good' copy, we're probably going to get better results by just matching strings to those known goods, rather than trying to build in morpho-syntatic understanding.

So we are much, much better off working on increasing the basic performance of OCR under Ocropus (and Tesseract), and creating this sort of training material is the easiest way to do this in bulk.
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