Benchmarking computer vision transcription of historical handwritten documents

Summary

For automatic transcription of most historical handwritten cursive script documents, Microsoft Azure is the most accurate computer vision provider, with the exception for very hard to read documents where Google Cloud leads.

Scaled scores:

  • MS Azure: 91
  • Google Cloud: 89
  • Amazon AWS: 11

Sample of the MS Azure transcription of the George Swinburne diary

Table of contents

Introduction

Thanks to the generous funding of the State Library of Victoria’s (SLV) Digital Fellowship program, I have been able to start work on the development of an open source service ( biblio.ai ) for institutional libraries to use the latest in computer vision technologies to automatically enrich the metadata of their image collections.

The 3 main areas of automatic metadata enrichment will be:

  • Transcription of handwriting and text in images ( handwritten notes, typed text, even words in signs,etc.. )
  • Object detection for tagging/labeling (pick out the main objects in an image - enable users to browser a collection via tags etc..)
  • Automatic descriptions of images (adding human readable descriptions in bulk to an image collection, where existing records may have little or no metadata/cataloguing)

The purpose of metadata enrichment with computer vision is:

  • Discoverability. Enable the discoverability and re-use of a libraries digital collections by a much greater audience.
  • Accessibility. Without rich metadata a libraries image collection is inaccessible to vision impaired users.
  • Automate the hard stuff for libraries. Institutional libraries such as the SLV have millions of scanned images, but only a small fraction of these (the really important works) get transcribed (it’s expensive and very time consuming)

An example of how time consuming transcription can be. The SLV’s volunteer run project to transcribe the 25 volumes of the diaries of Joseph Jenkins (an itinerant labourer in gold rush era Central Victoria), has so far taken 10 years to get through 15 volumes. The YouTube video and document linked below have some great details on this transcription project.

The first step in this project is to benchmark the available computer vision technologies to identify which the most suitable for the various types of collections and institutions.

By far, the most useful thing computer vision can do for institutions libraries with image collections is the transcription of words (specifically cursive handwriting) in images to text. Making huge collections of images and documents searchable and accessible.

Automatic transcription of typed text documents via standard OCR software has been available for years. It is only very recent that transcription of cursive handwritten images has started to move from purely academic space to being generally available from leading cloud providers.

For conversion of scanned handwritten documents to text there are currently (Jan 2020) 4 main providers.

Notes: unfortunately ABBYY is suitable only for form style block letter handwriting conversion and the leading open source OCR solution Tesseract is currently not easily suitable for general handwriting recognition. Both of these options have been excluded in the following tests.

Benchmarking

Images of various degrees of difficulty to read/transcribe were selected from SLVs and Swinburne Universities image collections. If the image had an existing transcription - this was used as the base to compare the computer vision transcriptions against. If a transcription didn’t exist I manually transcribe the image to use as the base.

Each automated transciption was analysed for the number of words there were correctly transcribed. Correctly being defined as all letters in a word matching the base transcription.

The number of words correct per transciption was then converted to a percentage and then scaled based on the perceived difficulty of the text.

Benchmark results

Document Age (years) Difficulty MS Azure Google Cloud Amazon AWS
Swinburne: George Swinburne’s diary, 1882 page 4 138 Hard 79% 62% 7%
Swinburne: Letter from aboard S.S. Shropshire 100 Medium 78% 66% 4%
SLV: Diary of Charles Evans, 1853 - page 7 167 Very Hard 60% 75% 3%
SLV: Christmas 1888. A page from an illustrated diary 132 Easy 95% 92% 49%
Average     78% 74% 16%

Scaled for difficulty: Easy = .5, Medium = 1, Hard = 1.5, Very Hard = 2

  • MS Azure: 91
  • Google Cloud: 89
  • Amazon AWS: 11

George Swinburne’s diary, 1882 to 1886 page 4

Preview:

Human transcription

3rd Feb 1882

This is my 21st birthday! I am a man! very significant that; as father says, I will have to think and act for myself now. Well, with God's help I will endeavour to do right I live a thruthtful, righteous & sober life. It is my aim ever to better myself, although I sometimes miserably, oh! miserably fail. I've got a temper, which wants conquering, & a heart, that often harbours most wicked & vile thoughts, cleansing. God strengthen me in my warfare & help me to live the life I have to live nobly & well, always prepared to die.

I have been a Sunday School Teacher for about 7 years, that has done me a power of good, & my feeble efforts at working for Christ on the Sunday, have often fortified me for the next week. One needs spiritual armour on the Quayside. I see more of what people term 'life' on the Quay, than I expected when I first went, but I am fortunate in being a good office, where I have been for 7 years (come 18th May). The best way to conquer evil thoughts is to work hard, at least,

193 Words

MS Azure transcription

god Feb 1882   
This is my bit birthday! I'm aman   
very significant that, as father days, Swill have
to think and act for myself now. Well, with 
God's help I will endeavour to do right Hive a 
truthful, righteous asober life. It is my aim 
ever to bett mapelf, although Isorhetimes 
miserably, oh miserably foul. lie got a 
temper, which wants conquering, Dad heart that 
often harbours most wicked Write thoughts, 
cleansing. God strengthen me in my warfare 
thell she to live the life I have to live nobly twell, 
always prepared to did. 

Is have been a Sunday School Teacher for   
about 4 years, that has done me a power of  
good, Imy feeble efforts at working for Christ 
low the Sunday, have often fortified me for 
the next weekd. ones needdo spirituall armour oh the 
Wayside. Isee more of what people term life on 
the away, than Sexplated when I first went, but 
Sam fortunate in being in a good office , where 
I have been for yyears / come 18th may). 
The best way to conquer edit thoughts is to work hard, at least, 

152 words correct = 79%

Google Cloud transcription

grd Feb. 1982   
This is my 214 birthday! So am   
very significant thatli as father day, will have  
Etichoke land act for mopelfmou. Well, with  
Gods heff I will endeavour/t dorught Mive a  
truthful, righteous tsober life. It is my aim  
ever te letter mpelf, although Seorhetines  
miserables, oh! miserably fail. I've gota   
tempe, Thich warto coslabering, Mal heart that 
often harbouro most wicked Bila thought, 
dansing. Lod shengthens me in my was fase  
Shelf she to live the life I have to like no hd, Puell 

I have been a Sunday School Teacher for 
about y years, that has done me a powerlof 
good, ding feeble effato at working for Christ  
on the Sunday, have often fortified me for 
the next weeld. Onei neelde Sikituallarmour on the 
Luapide. Isee mme of what people term 'life on 
the way, than Iexpleted when I first went, but 
I am fortunate in being in a good office, where  
Shave been for Y yearo come 1st May). \"The best way 
to conquer evil thought in to work hard, at least, 

119 words correct = 62%

AWS Rekognition transcription

grd Hef 1882
This 2/2 Lirthday! Sim
thal is my La ther vill aman. Have
y t thile uign ft as dayi
Lod and act for mou Mell wth
hel will endeawour t doreg ht rlive a
LuLh ighleos soher e L Itisa aime
ever l Le ttod mspey althhughe aohe times
serafla

14 words correct = 7%

Swinburne : Letter from aboard S.S. Shropshire

Preview:

Note: Image is of undetermined copyright status and is provided here for educational purposes

Human transcription

S.S. Shropshire
At Sea
4th March 19120

Mr F.W. Green.
Dear Sir,

We are off to Freemantle for another 40,000 Boxes of apples after loading 110,00 at Hobart. We did not call at Melbourne again. We will land 6,000 Boxes of Butter at Freemantle from Sydney.

Will you please remember me to Mr Waters & to my fiends at My College and with best wishes to yourself I remain

Yours faithfully
John Duncan

Word count: 77

MS Azure transcription

S.S.  
Shropshire
my. N. Green.  
Aff March. 19120, 
Dear Dien We are off- to Freemantle 
for another 40.000 Boxes of apples after 
loading 1 10.000, at Nobrash, wel did not call at 
Melbourne, again. We will land 6.000. Boxes 
of Butter atfreemantle from Sydney . 
Will you please remember me 
to Mr Waters & bol my friends at Me  
College. and with best wishes to 
yourself 
I pemain
yours faithfully 
John. Duncan 

60 words correct = 78%

Google Cloud transcription

S.s. Ohropshire  
lat sea  
4 Wareh. 19120, 
Mr J. W. Green. 
Dear Sire We are off to freemantle 
for another 40,000 Bosces of apples after 
Loading 110000, at Hobart, wobel did not eallah 
Melbfturne, again. He will land 6.000. Boces 
of Buter and Freemande from Sydney. 
Will you fleebe femember me 
to Me Waters e to my friends at the 
College and with Post wishes to : 
yourself 
Yours faithfully 
seman
can

51 words correct = 66%

AWS Rekognition transcription

S.S. ehrefiuhi ea
Woes areh. 191 20.
Greeen
We al f b Freemanl
or anothe 40:0 Noba: Boeis
ples olidl plo aplen oallo
Hoarding Melo frne 1/10000, al
gain. Me u'llland 6.00D. Bocoo
BBuMer a antle ylny.
Iill fe bpe me

3 words correct = 4%

SLV: Christmas 1888. A page from an illustrated diary

Preview:

Human transcript (guessed words mark in “”):

Christmas. 1888. A page from "my" illustrated diary. Drawn by Uncle Charlie. Belgrave. Victoria. Australia. for Christopher Fry.
With every good wish for a h"app"y and prosperous future.
Out party from S"t. Mary's Fie"lds passing through Belgrave. Leicestershire to a meet of the Pychley "Hound"s.

Word cout of translatable words: 39

MS Azure transcription

Christmas. 1888. A page from T illustrated diary. Drawn by Uncle Charlie. Belgrave. Victoria. Australia. for Chridapher Fry.
With every good wish for a har y and prosperous future.
Our Party from Sri Lids passing Through Betgrave. Leicestershire to a meet of the Pychley

37 words correct = 95%

Google Cloud transcription

Christmas. 1888. A page from illustrated diary.   7
Drawn by Uncle Charlie. Belgrave. Victoria. Australia. for Chruida pher Fry,  9
With every good wish for a har y and prosperous fuhre,  8
Our Party from Sm i ds passing through Belgrave Leicestershire to a meet of the Py chley  12

36 words correct = 92%

AWS Rekognition transcription

Chrishmas. 1888. pace from illustrated diary. Drawn by uincle Chaplie. Belgrave. Victoria Australia. for Chridlapher Fry.
With every dood wish and prosperous fuhre.      
Our parly jrom passing Through graveleiceshershire te mectof Hhe Pychlay     

39 words correct = 49%

SLV : Diary of Charles Evans, 1853 September 24 -1855 January 21 - page 7

For more information of the UNESCO listed Charles Evans diary: https://blogs.slv.vic.gov.au/news/unesco-adds-gold-rush-diaries-to-australian-memory-of-the-world-register/

Preview:

Transcript

Saturday Sep 24th 1853

         Very busy all day preparing our establish-
         ment previous to it being transferred to
         two young men who will probably make
         more of it than we have as they are quite
         conversant with the business. They came
         up in the evening and took possession
         after paying us 100£ in Cash and 3 months
         bill for 50£ for the stock tents good
         will &c - As for the "good will" they
         have that as far as I am concerned
         in every sense of the term, for am heartily
         sick of the fumes of the oven and dispensing
         lolly-sticks and comfits to the colonial
         small fry. We celebrated the event with
         a glass and a song, and made the night
         of our parting with the old tent as merry
         a one as any we had passed in it.

Sunday Sep 25th
         Andrew Martin and two of his friends
         paid us a visit.

153 words

MS Azure transcription

I wesday defy Saturday def 14- 
the 185 3
very busy all day prepare our bolablinds 
two young new who will probably make
more of it than we have, as they are quite
conversant with the bushup. they carne 
chop in the evening aunt took badsession 
after paying u. 108 I in Cash and 3 month. 
will for fot for the Mock teats good 
will to - he for the good well" they 
has that and far and i am concernis 
In every devise of he term, for Aam heart  
sick of the farmer of the oven and disforcing  
lolly- sticks and coutilt to the & colonial 
small fry.. We celebrates the event with 
a glass and a song, and moises the might  
It our cartry with the ots tent at Marry 
hair us a visit. 

92 words correct = 60%

Google Cloud transcription

Tuesday Sess Saturday Ach 24th 1853 

Veg betyr all day prepare our bestabbits 
Mente previous t ih beung transferred to 
two young men who will prosrably make 
Mone of it than we have, as they are quite 
conversant with the basiese – They came 
ich in the evening and took possession 
after payung us 100 L in Cash And 3 month, 
fill for 50th for the slock that good 
will fe. – Act for the good well\" They 
Lind that as far as I am concerned a 
in every sense of the teren, for all am hearts 
sick of the frames of the oven and dispersing
lolly-sticks and confit to the & colonial
small fry.. We celebrated he event with
a glass and a song, and made the night
of our partag with the old tent at Merry
a one as aug me had passed in it

Andrew Martin and two de le friend 
paid usa vitit.  1

115 words correct = 75%

AWS Rekognition transcription

K 1833
Lasblay sf Satu' ay ode! 24- bsabhlk
rry ndy ale Pay bhef ary houfere our
arut pnevrro! eny prake,
Fur men wl toll rfrohl
Mo Y 1 Han wve Lave bs a Haey one ga
cone nsan wl e looN hub. dbussion Hy cone
uf hy Hh om

4 words correct = 3%

Conclusion

For automatic transcription of most historical handwritten cursive script documents, Microsoft Azure is the most accurate computer vision provider, with the exception for very hard to read documents where Google Cloud leads.

For more information on the project behind this post please refer to biblio.ai. Feel free to contact me if you have any queries or comments.

Next steps

Given how well Google Cloud performed with the very hard to read Charles Evans diary I’ll take some samples from the super hard Jenkins diaries for analysis. Anything above 0% accuracy for alot of these pages would be an amzaing result.

Text extraction from historical maps the SLV have will then be the next area for benchmarking.

Notes and acknowledgements

Thanks to the team at the State Library of Victoria and Swinburne University Library for sourcing and assitance with the images!

Note that the copyright of some of these images may be undetermined status and is provided here for educational purposes.

Source code of this page is available on GitHub. If you spot any issues with this post either post in the comments or in GitHub.

Sourse code used to do the transcriptions for the various cloud providers will be available: https://github.com/justinkelly/biblio.ai

Justin Kelly

Justin Kelly

Web Developer, Business Analytics, Data Engineer specialising in PHP and Tableau

Based in Melbourne, Australia

Feel free to contact me justin@kelly.org.au or _justin_kelly

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