.NET OCRing an Image

Question

I\'m trying to use MODI to OCR a window\'s program. It works fine for screenshots I grab programmatically using win32 interop like this:

public string SaveScreen         


        

Answer 1

Looks as though the answer is in giving MODI a bigger canvas. I was also trying to take a screenshot of a control and OCR it and ran into the same problem. In the end I took the image of the control, copied the image into a larger bitmap and OCRed the larger bitmap.

Another issue I found was that you must have a proper extension for your image file. In other words, .tmp doesn't cut it.

I kept the work of creating a larger source inside my OCR method, which looks something like this (I deal directly with Image objects):

public static string ExtractText(this Image image)
{
    var tmpFile = Path.GetTempFileName();
    string text;
    try
    {
        var bmp = new Bitmap(Math.Max(image.Width, 1024), Math.Max(image.Height, 768));
        var gfxResize = Graphics.FromImage(bmp);
        gfxResize.DrawImage(image, new Rectangle(0, 0, image.Width, image.Height));
        bmp.Save(tmpFile + ".bmp", ImageFormat.Bmp);
        var doc = new MODI.Document();
        doc.Create(tmpFile + ".bmp");
        doc.OCR(MODI.MiLANGUAGES.miLANG_ENGLISH, true, true);
        var img = (MODI.Image)doc.Images[0];
        var layout = img.Layout;
        text = layout.Text;
    }
    finally
    {
        File.Delete(tmpFile);
        File.Delete(tmpFile + ".bmp");
    }

    return text;
}

I'm not sure exactly what the minimum size is, but it appears as though 1024 x 768 does the trick.