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Rob  
#1 Posted : Wednesday, January 20, 2021 2:10:10 PM(UTC)
Rob

Rank: Administration

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Groups: Translators, Members, Administrators
Joined: 1/11/2018(UTC)
Posts: 952
United States
Location: Tampa, FL

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Was thanked: 274 time(s) in 239 post(s)
DISCLAIMER:

I am not versed in Tesseract nor OCR beyond understanding what they are in general. I simply pulled together the necessary files and two supporting methods in the SPTesseract class to be able to make this work.
I have only tested this in the most basic way, selecting an area with a light background and dark, legible, text.



Plug-In and Required Files:

https://www.strokesplus.net/files/plugins/SPTesseract_1.0.0.0.zip (177 MB)

IMPORTANT:
- You must have a minimum version of StrokesPlus.net 0.4.1.1
- Extract all files/folders directly into StrokesPlus.net\Plug-Ins folder using 7-Zip or some other method which doesn't block the DLLs
- If you update the current working directory used by S+, this might fail to load the trained data files
- Should look like the image below





Put this function in Global Actions > Load/Unload > Load (script):
This is a wrapper for extracting text based on a language and rectangle
Code:
function GetTesseractText(lang, rect) {

    //Capture an image from the screen using the Rectangle passed in

    var memoryImage = new drawing.System.Drawing.Bitmap(rect.Width, rect.Height);
    var memoryGraphics = drawing.System.Drawing.Graphics.FromImage(memoryImage);
    memoryGraphics.CopyFromScreen(rect.X, rect.Y, 0, 0, new Size(rect.Width, rect.Height));
    memoryGraphics.Dispose();

    /*
    Get Tesseract Page object 
     
    First param in Bitmap image
      - From code above

    Second param is language
      - See Plug-Ins\TesseractTrainedData folder for other trained data files
      - Appears to be just the first part of the file name; "eng" for English

    Third param is Tesseract.EngineMode enum value: 
      - TesseractOnly = "0"
      - LstmOnly = "1"
      - TesseractAndLstm = "2"
      - Default = "3"

    Last param is Tesseract.PageSegMode
      - OsdOnly = "0"
      - AutoOsd = "1"
      - AutoOnly = "2"
      - Auto = "3"
      - SingleColumn = "4"
      - SingleBlockVertText = "5"
      - SingleBlock = "6"
      - SingleLine = "7"
      - SingleWord = "8"
      - CircleWord = "9"
      - SingleChar = "10"
      - SparseText = "11"
      - SparseTextOsd = "12"
      - RawLine = "13"
      - Count = "14"

    SPTesseract class also has the function below defined:

    List<Rectangle> GetPageSegmentedRegions(Page page, string iteratorLevel)

    Pass Page object from the SPTesseract.GetPage method with one of the PageIteratorLevel values:
    Tesseract.PageIteratorLevel
    
      - Block = "0"
      - Para = "1"
      - TextLine = "2"
      - Word = "3"
      - Symbol = "4"

    All other methods/properties are standard Tesseract 4.1.1 from:
     - https://www.nuget.org/packages/Tesseract/
     - https://github.com/charlesw/tesseract


  */
    var tpage = SPTesseract.GetPage(memoryImage, lang, "3", "3");
    return tpage.GetText();
}

Example action script to test recognition and show source rectangle:
Code:
//Use the square gesture, to draw a box around the desired area
//Shows the text recognized by Tesseract (English data file) and the dimensions of the rectangle

sp.MessageBox(`Text: ${GetTesseractText("eng", new Rectangle(action.Bounds.X, action.Bounds.Y, action.Bounds.Width, action.Bounds.Height))}
Rect.X: ${action.Bounds.X}
Rect.Y: ${action.Bounds.Y}
Rect.Width: ${action.Bounds.Width}
Rect.Height: ${action.Bounds.Height}`, 
"Text, Rect");

Edited by user Wednesday, January 20, 2021 2:33:29 PM(UTC)  | Reason: Not specified

thanks 1 user thanked Rob for this useful post.
AppleBag on 4/17/2021(UTC)
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