ByteScout Text Recognition SDK – PowerShell – Image Preprocessing Filters

ByteScout Text Recognition SDK – PowerShell – Image Preprocessing Filters

ImagePreprocessingFilters.ps1

# Add reference to ByteScout.TextRecognition.dll assembly
Add-Type -Path "c:\Program Files\ByteScout Text Recognition SDK\net40\ByteScout.TextRecognition.dll"

$InputDocument = "..\..\skewed.png"
$OutputDocument = ".\result.txt"

# Create and activate TextRecognizer instance
$textRecognizer = New-Object ByteScout.TextRecognition.TextRecognizer
$textRecognizer.RegistrationName = "demo"
$textRecognizer.RegistrationKey = "demo"

try {
    # Load document (image or PDF)
    $textRecognizer.LoadDocument($InputDocument)

    # Set location of "tessdata" folder containing language data files
    $textRecognizer.OCRLanguageDataFolder = "c:\Program Files\ByteScout Text Recognition SDK\tessdata\"

    # Set OCR language.
    # "eng" for english, "deu" for German, "fra" for French, "spa" for Spanish etc - according to files in "tessdata" folder
    # Find more language files at https:#github.com/tesseract-ocr/tessdata/tree/3.04.00
    $textRecognizer.OCRLanguage = "eng"


    # Add deskew filter that automatically rotates the image to make the text horizontal.
    # Note, it analyzes the left edge of scanned text. Any dark artifacts may prevent 
    # the correct angle detection.
    $textRecognizer.ImagePreprocessingFilters.AddDeskew()

    # Other filters that may be useful to improve recognition
    # (note, the filters are applied in the order they were added):

    # Improve image contrast.
    #$textRecognizer.ImagePreprocessingFilters.AddContrast()

    # Apply gamma correction.
    #$textRecognizer.ImagePreprocessingFilters.AddGammaCorrection()

    # Apply median filter. Helps to remove noise.
    #$textRecognizer.ImagePreprocessingFilters.AddMedian()

    # Apply dilate filter. Helps to cure symbols erosion.
    #$textRecognizer.ImagePreprocessingFilters.AddDilate()

    # Lines removers. Removing borders of some tables may improve the recognition.
    #$textRecognizer.ImagePreprocessingFilters.AddHorizontalLinesRemover()
    #$textRecognizer.ImagePreprocessingFilters.AddVerticalLinesRemover()


    # Recognize text from all pages and save it to file
    $textRecognizer.SaveText($OutputDocument)

    # Open the result file in default associated application (for demo purposes)
    & $OutputDocument
}
catch {
    # Display exception
    Write-Host $_.Exception.Message
}

$textRecognizer.Dispose()

run.bat

@echo off

powershell -NoProfile -ExecutionPolicy Bypass -Command "& .\ImagePreprocessingFilters.ps1"
echo Script finished with errorlevel=%errorlevel%

pause

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