/// <summary>
/// Performs OCR for bulk/batch and console operations.
/// </summary>
/// <param name="imageFile">Image file</param>
/// <param name="outputFile">Output file without extension</param>
/// <param name="langCode">language code</param>
/// <param name="pageSegMode">page segmentation mode</param>
/// <param name="outputFormat">format of output file. Possible values: <code>text</code>, <code>text+</code> (with post-corrections), <code>hocr</code></param>
public static void PerformOCR(string imageFile, string outputFile, string langCode, string pageSegMode, string outputFormat)
{
IList <Image> imageList;
try
{
DirectoryInfo dir = Directory.GetParent(outputFile);
if (dir != null && !dir.Exists)
{
dir.Create();
}
bool postprocess = "text+" == outputFormat;
OCR <Image> ocrEngine = new OCRImages();
ocrEngine.PageSegMode = pageSegMode;
ocrEngine.Language = langCode;
ocrEngine.OutputFormat = outputFormat.Replace("+", string.Empty);
// convert PDF to TIFF
if (imageFile.ToLower().EndsWith(".pdf"))
{
imageFile = PdfUtilities.ConvertPdf2Tiff(imageFile);
}
imageList = ImageIOHelper.GetImageList(new FileInfo(imageFile));
string result = ocrEngine.RecognizeText(imageList, imageFile);
// post-corrections for text+ output
if (postprocess)
{
// postprocess to correct common OCR errors
result = Processor.PostProcess(result, langCode);
// correct common errors caused by OCR
result = TextUtilities.CorrectOCRErrors(result);
// correct letter cases
result = TextUtilities.CorrectLetterCases(result);
}
//if (outputFormat == "pdf") // not yet supported
//{
// byte[] bytes = null; // get the byte array
// File.WriteAllBytes(outputFile, bytes);
//}
//else
{
string filename = outputFile + "." + outputFormat.Replace("+", string.Empty).Replace("text", "txt").Replace("hocr", "html");
using (StreamWriter sw = new StreamWriter(filename, false, new System.Text.UTF8Encoding()))
{
sw.Write(result);
}
}
}
finally
{
imageList = null;
}
}
private void backgroundWorkerMergePdf_DoWork(object sender, DoWorkEventArgs e)
{
ArrayList args = (ArrayList)e.Argument;
string[] inputFiles = (string[])args[0];
string outputFile = (string)args[1];
PdfUtilities.MergePdf(inputFiles, outputFile);
e.Result = outputFile;
}
/// <summary>
/// Performs OCR for bulk/batch and console operations.
/// </summary>
/// <param name="imageFile">Image file</param>
/// <param name="outputFile">Output file without extension</param>
/// <param name="langCode">language code</param>
/// <param name="pageSegMode">page segmentation mode</param>
/// <param name="outputFormat">format of output file. Possible values: <code>text</code>, <code>text+</code> (with post-corrections), <code>hocr</code></param>
public static void PerformOCR(string imageFile, string outputFile, string langCode, string pageSegMode, string outputFormat)
{
DirectoryInfo dir = Directory.GetParent(outputFile);
if (dir != null && !dir.Exists)
{
dir.Create();
}
bool postprocess = "text+" == outputFormat;
OCR <Image> ocrEngine = new OCRImages();
ocrEngine.PageSegMode = pageSegMode;
ocrEngine.Language = langCode;
ocrEngine.OutputFormat = outputFormat.Replace("+", string.Empty);
ocrEngine.OutputFile = outputFile;
// convert PDF to TIFF
if (imageFile.ToLower().EndsWith(".pdf"))
{
imageFile = PdfUtilities.ConvertPdf2Tiff(imageFile);
}
ocrEngine.ProcessFile(imageFile);
// post-corrections for text+ output
if (postprocess)
{
string filename = outputFile + ".txt";
string result = File.ReadAllText(filename);
// postprocess to correct common OCR errors
result = Processor.PostProcess(result, langCode);
// correct letter cases
result = TextUtilities.CorrectLetterCases(result);
using (StreamWriter sw = new StreamWriter(filename, false, new System.Text.UTF8Encoding()))
{
sw.Write(result);
}
}
}
private void backgroundWorkerSplitPdf_DoWork(object sender, DoWorkEventArgs e)
{
SplitPdfArgs args = (SplitPdfArgs)e.Argument;
if (args.Pages)
{
PdfUtilities.SplitPdf(args.InputFilename, args.OutputFilename, args.FromPage, args.ToPage);
}
else
{
string outputFilename = String.Empty;
if (args.OutputFilename.EndsWith(".pdf"))
{
outputFilename = args.OutputFilename.Substring(0, args.OutputFilename.LastIndexOf(".pdf"));
}
int pageCount = PdfUtilities.GetPdfPageCount(args.InputFilename);
if (pageCount == 0)
{
throw new ApplicationException("Split PDF failed.");
}
int pageRange = Int32.Parse(args.NumOfPages);
int startPage = 1;
while (startPage <= pageCount)
{
int endPage = startPage + pageRange - 1;
string outputFile = outputFilename + startPage + ".pdf";
PdfUtilities.SplitPdf(args.InputFilename, outputFile, startPage.ToString(), endPage.ToString());
startPage = endPage + 1;
}
}
e.Result = args.OutputFilename;
}
/// <summary>
/// Get image(s) from file
/// </summary>
/// <param name="imageFile">file name</param>
/// <returns>list of images</returns>
public static IList <Image> GetImageList(FileInfo imageFile)
{
string workingTiffFileName = null;
Image image = null;
try
{
// convert PDF to TIFF
if (imageFile.Name.ToLower().EndsWith(".pdf"))
{
workingTiffFileName = PdfUtilities.ConvertPdf2Tiff(imageFile.FullName);
imageFile = new FileInfo(workingTiffFileName);
}
// read in the image
image = Image.FromFile(imageFile.FullName);
IList <Image> images = new List <Image>();
int count;
if (image.RawFormat.Equals(ImageFormat.Gif))
{
count = image.GetFrameCount(FrameDimension.Time);
}
else
{
count = image.GetFrameCount(FrameDimension.Page);
}
for (int i = 0; i < count; i++)
{
// save each frame to a bytestream
using (MemoryStream byteStream = new MemoryStream())
{
image.SelectActiveFrame(FrameDimension.Page, i);
image.Save(byteStream, ImageFormat.Png);
// and then create a new Image from it
images.Add(Image.FromStream(byteStream));
}
}
return(images);
}
catch (OutOfMemoryException e)
{
throw new ApplicationException(e.Message, e);
}
catch (System.Runtime.InteropServices.ExternalException e)
{
throw new ApplicationException(e.Message + "\nIt might have run out of memory due to handling too many images or too large a file.", e);
}
finally
{
if (image != null)
{
image.Dispose();
}
if (workingTiffFileName != null && File.Exists(workingTiffFileName))
{
File.Delete(workingTiffFileName);
}
}
}
