{"id":2312,"date":"2012-07-28T00:00:00","date_gmt":"1970-01-01T00:00:00","guid":{"rendered":"http:\/\/johnjohnston.info\/blog\/?e=2312"},"modified":"2012-07-28T00:00:00","modified_gmt":"1970-01-01T00:00:00","slug":"ocr-via-dropbox-with-tesseract","status":"publish","type":"post","link":"https:\/\/johnjohnston.info\/blog\/ocr-via-dropbox-with-tesseract\/","title":{"rendered":"OCR via dropbox with Tesseract"},"content":{"rendered":"\n

This is going to be another slightly geeky post. The previous one, Testing a new system<\/a>, was about a way to blog using dropbox and AppleScript folder actions had me thinking about other things that could be done using this sort of system. The way I am doing this relays on having dropbox and a mac that is on when you want it. If you don’t have a mac you might like Wappwolf<\/a> which is a web service that can do a lot of things with files in your dropbox automatically.<\/p>\n

So I already have a system for blogging by dropping files into a folder on my dropbox<\/a> and was looking around for another idea to play with. There seems to be a few OCR apps for iPhones but I had noticed that Tesseract<\/a> was available on Google Code<\/a> and googled around to see how it could be installed and run on a mac. One I found was TesseractOCR Mac<\/a> a Cocoa Front end to the Tesseract OCR program. I downloaded this and gave it a try. It worked well on my desktop. I then struck gold: Installing and using Tesseract 2.04 on Mac OS X 10.6.6 with Homebrew | Ramble On<\/a>. This post explains clearly how to install Tesseract on a mac so that it can be used on the command line. It is also a good intro to homebrew<\/a>.<\/p>\n

Homebrew<\/h3>\n

Homebrew is the easiest and most flexible way to install the UNIX tools Apple didn’t include with OS X.<\/p><\/blockquote>\n

For someone who has struggled with this sort of thing before, homebrew is pretty straightforward. Installing homebrew is just a case of copying a line of code from the installation<\/a> page, pasting it into the terminal and pressing return.<\/p>\n

imagemagick<\/h3>\n

Following the instructions<\/a> from Ramble On I just typed brew install imagemagick<\/em> in the terminal and hit return. Lots of scary text scrolls by:<\/p>\n

\"Install<\/p>\n

installing Tesseract<\/h3>\n

Once imagemagick was installed I repeated the process for Tesseract.<\/p>\n

Testing Tesseract<\/h3>\n

As I was wanting to figure out how to use my phoe for OCR I took a photo of a bit of newspaper, I used Camera+<\/a>, the clarity filter, cropped and made the image Black and White:<\/p>\n

\"fr_160\"<\/a>
Click the image to see fullsized on flickr<\/p>\n

I used Wifi Photo Transfer<\/a> to grab the photo from my camera and put it on the desktop.\n<\/p>\n

The OCR process is in two steps using the terminal and the newly installed applications:<\/p>\n

    \n
  1. Convert to 200dpi tiff:
    cd Desktop
    convert -density 200 -units PixelsPerInch -type Grayscale +compress fr_160.jpg fr_160.tif<\/em><\/li>\n
  2. Preform OCR on the tif
    tesseract fr_160.tif fr_160 -1 eng<\/em><\/li>\n<\/ol>\n

    \tI now have two extra files on my desktop, fr_160.tif and fr_160.txt, the txt file contains the OCR text:<\/p>\n

    (_;oogle is facing fresh criticism after\nadmitting that it has not deleted all of the\nprivate data, including emails and pass-\nwords, it secretly collected from internet\nusers around the UK as it gathered data for\nits Street View maps.\nThe search firm was ordered in Decem-\nber 2010 to delete the private information\nhoovered up by its Street View cars from\nopen Wi-Fi networks. r\nBut yesterday Google told the Infor-\nmation Commissioner’s Office “human\nerror” had prevented it from erasing the\ndata, which could include the millions of\nemails and passwords .\nGoogle admitted in May 2010 its Street\nView cars had “mistakenly” collected pri-<\/pre>\n
    Which is pretty good.<\/p>\n
    OCR for dropbox<\/h3>\n
    I now can see that tesseract works well and needed to make it work on images added to a particular dropbox folder.<\/p>\n
    There are a few folder action scripts that come with a mac, there are in \/Library\/Scripts\/Folder Action Scripts\/ several of these deal with images files ad contain routines for handling the dropping of files. These ‘standard’ routines move added files of the correct file type to a subfolder and then pass them on to a sub-routine that deals with the files. I could just duplicated one of these and edit the process_item<\/em> sub routine. Basically I just scripted the process tested above. I’ve uploaded the script ocr folder action<\/a> as html, incase anyone will find it useful or fun. <\/p>\n
    To use the script you put it in the Folder Action Scripts (copy the text of the html file paste it in the appleScript script editor.). Add a folder to dropbox and attached the script to that (right click on the folder and choose Folder Actions Setup…<\/strong>).<\/p>\n
    Most of my bit of the script just uses do shell script<\/strong> to run the scripts above, the only gotcha was that although I can use convert<\/em> in the terminal, in a script I have to use the full path to the script:
    set ocrscript to <\/p>\n
    "\/usr\/local\/Cellar\/tesseract\/3.01\/bin\/tesseract '" & tif_file & "' '" & tif_file & "' -1 eng"

    \n\t\tdo shell script ocrscript<\/em><\/p>\n
    This is to do with the way homebrew installs applications and the fact AppleScript doesn’t access commands from \/usr\/local\/…<\/strong>.<\/p>\n
    My script<\/a> is fairly crude, especially about file endings, if I add :Photo 28-07-2012 12 35 55.jpg<\/strong> to the dropbox folder, it is moved into the processed files folder and Photo 28-07-2012 12 35 55.jpg.tif<\/strong> and Photo 28-07-2012 12 35 55.jpg.tif.txt<\/strong> are created. Not elegant.<\/p>\n
    The whole process from taking a photo to opening the txt file in dropbox only takes a couple of minutes when using 3G. The system will not deal with columns or more than a single block of text but it does that fairly well. Mostly it was fun to figure out how to do.<\/p>\n","protected":false},"excerpt":{"rendered":"
    This is going to be another slightly geeky post. The previous one, Testing a new system, was about a way to blog using dropbox and AppleScript folder actions had me thinking about other things that could be done using this sort of system. The way I am doing this relays on having dropbox and a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"mf2_syndication":[],"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"webmentions_disabled_pings":false,"webmentions_disabled":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[6],"tags":[93,94,120,127,128],"post_format":[],"class_list":{"0":"post-2312","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-wwwd","7":"tag-applescript","8":"tag-commandline","9":"tag-dropbox","10":"tag-ocr","11":"tag-osx","12":"kind-","13":"h-entry","14":"hentry"},"better_featured_image":null,"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p57zFQ-Bi","jetpack_likes_enabled":false,"jetpack_sharing_enabled":true,"kind":false,"_links":{"self":[{"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/posts\/2312","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/comments?post=2312"}],"version-history":[{"count":0,"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/posts\/2312\/revisions"}],"wp:attachment":[{"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/media?parent=2312"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/categories?post=2312"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/tags?post=2312"},{"taxonomy":"post_format","embeddable":true,"href":"https:\/\/johnjohnston.info\/blog\/wp-json\/wp\/v2\/post_format?post=2312"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}