[Chargeable] RSTessOCR - Optical Character Recognition Offline

Tesseract is probably the most accurate open source OCR engine available. Combined with the Leptonica Image Processing Library it can read a wide variety of image formats and convert them to text in over 60 languages. It was one of the top 3 engines in the 1995 UNLV Accuracy test. Between 1995 and 2006 it had little work done on it, but since then it has been improved extensively by Google. It is released under the Apache License 2.0.

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RSTessOcr
Author: XverhelstX
Version: 1

• RSTessOcr
  Fields:
  • OEM_CUBE_ONLY As Int
    Run Cube only - better accuracy, but slower
  • OEM_DEFAULT As Int
    Default OCR engine mode.
  • OEM_TESSERACT_CUBE_COMBINED As Int
    Run both and combine results - best accuracy
  • OEM_TESSERACT_ONLY As Int
    Run Tesseract only - fastest
  • VAR_CHAR_BLACKLIST As String
    Blacklist of characters to not recognize.
  • VAR_CHAR_WHITELIST As String
    Whitelist of characters to recognize.
  Methods:
  • Clear
    Frees up recognition results and any stored image data, without actually
    freeing any recognition data that would be time-consuming to reload.
    Afterwards, you must call SetImage or SetRectangle before doing any
    Recognize or Get* operation.
  • Initialize (EventName As String, Datapath As String, Language As String)
    Initializes the Tesseract engine with a specified language model.
    
    Instances are now mostly thread-safe and totally independent, but some
    global parameters remain. Basically it is safe to use multiple
    TessBaseAPIs in different threads in parallel, UNLESS you use SetVariable
    on some of the Params in classify and textord. If you do, then the effect
    will be to change it for all your instances.
    EventName:
    Datapath: The path to you Tesseract folder. THE FOLDER SHOULD CONTAIN A SUBFOLDER NAMED "tessdata".
    Language: The language that should be used. usually "eng".
    
    Returns true on success.
  • Initialize2 (EventName As String, Datapath As String, Language As String, EngineMode As Int) As Boolean
    Initializes the Tesseract engine with a specified language model with the given engine constants..
    
    Instances are now mostly thread-safe and totally independent, but some
    global parameters remain. Basically it is safe to use multiple
    TessBaseAPIs in different threads in parallel, UNLESS you use SetVariable
    on some of the Params in classify and textord. If you do, then the effect
    will be to change it for all your instances.
    EventName:
    Datapath: The path to you Tesseract folder. THE FOLDER SHOULD CONTAIN A SUBFOLDER NAMED "tessdata".
    Language: The language that should be used. usually "eng".
    
    Returns true on success.
  • IsInitialized As Boolean
  • MeanConfidence As Int
    Returns the mean confidence of text recognition.
    Return type: @return:the mean confidence
  • Release
    Closes down tesseract and free up all memory. Release() is equivalent to
    destructing and reconstructing your TessBaseAPI.
    <p>
    Once Release() has been used, none of the other API functions may be used
    other than Init and anything declared above it in the class definition.
  • Scan
    Scans the image and raises _Scanned (Text as string)
  • WordConfidences As Int[]
    Returns all word confidences (between 0 and 100) in an array. The number
    of confidences should correspond to the number of space-delimited words
    in GetUTF8Text().
    Return type: @return:an array of word confidences (between 0 and 100) for each
    space-delimited word returned by GetUTF8Text()
  • setImage2 (imagedata() As Byte, width As Int, height As Int, bpp As Int, bpl As Int)
    Provides an image for Tesseract to recognize. Copies the image buffer.
    The source image may be destroyed immediately after SetImage is called.
    SetImage clears all recognition results, and sets the rectangle to the
    full image, so it may be followed immediately by a GetUTF8Text, and it
    will automatically perform recognition.
    imagedata: byte representation of the image
    width: image width
    height: image height
    bpp: bytes per pixel
    bpl: bytes per line
  • setRectangle (left As Int, top As Int, width As Int, height As Int)
    Restricts recognition to a sub-rectangle of the image. Call after
    SetImage. Each SetRectangle clears the recogntion results so multiple
    rectangles can be recognized with the same image.
    left: the left bound
    top: the right bound
    width: the width of the bounding box
    height: the height of the bounding box
  • setVariable (var As String, value As String) As Boolean
    Set the value of an internal "variable" (of either old or new types).
    Supply the name of the variable and the value as a string, just as you
    would in a config file.
    <p>
    Example: <code>setVariable(VAR_TESSEDIT_CHAR_BLACKLIST, "xyz"); to ignore x, y and z. * setVariable(VAR_BLN_NUMERICMODE, "1"); to set numeric-only mode. * </code>
    <p>
    setVariable() may be used before open(), but settings will revert to
    defaults on close().
    var: name of the variable
    value: value to set
    Return type: @return:false if the name lookup failed
  Properties:
  • Debug As Boolean [write only]
    Sets debug mode. This controls how much information is displayed in the
    log during recognition.
  • Image As Bitmap [write only]
    Provides an image for Tesseract to recognize. Does not copy the image
    buffer. The source image must persist until after Recognize or
    GetUTF8Chars is called.
  • InitLanguagesAsString As String [read only]
    Returns the languages string used in the last valid initialization.
    If the last initialization specified "deu+hin" then that will be
    returned. If hin loaded eng automatically as well, then that will
    not be included in this list. To find the languages actually
    loaded use GetLoadedLanguagesAsVector.
  • PageSegMode As Int [write only]
    Sets the page segmentation mode. This controls how much processing the
    OCR engine will perform before recognizing text.

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bluedude said:

Tried it but not sure if it works. I get a lot of weird characters in a document. Which language does the demo apk support?

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• OEM_CUBE_ONLY As Int
  Run Cube only - better accuracy, but slower
• OEM_DEFAULT As Int
  Default OCR engine mode.
• OEM_TESSERACT_CUBE_COMBINED As Int
  Run both and combine results - best accuracy
• OEM_TESSERACT_ONLY As Int
  Run Tesseract only - fastest

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