Tesseract OCR Text Position

Question

I am working on OCR using tesseract. I am able to make the application working and get the output. Here i'm trying to extract data from an invoice bill and getting the extracted data. But the spacing between words in input has to be similar in output file.I am now getting each words and coordinates.I need to export to text file according to coordinates

Code Sample :

            using (var engine = new TesseractEngine(Server.MapPath(@"~/tessdata"), "eng", EngineMode.Default))
            {
                engine.DefaultPageSegMode = PageSegMode.AutoOsd;
                // have to load Pix via a bitmap since Pix doesn't support loading a stream.

                using (var image = new System.Drawing.Bitmap(imageFile.PostedFile.InputStream))
                {

                    Bitmap bmp = Resize(image, 1920, 1080);

                    using (var pix = PixConverter.ToPix(image))
                    {
                        using (var page = engine.Process(pix))
                        {
                            using (var iter = page.GetIterator())
                            {
                                iter.Begin();
                                do
                                {
                                    Rect symbolBounds;
                                    string path = Server.MapPath("~/Output/data.txt");
                                    if (iter.TryGetBoundingBox(PageIteratorLevel.Word, out symbolBounds))
                                    {
                                        // do whatever you want with bounding box for the symbol

                                    var curText = iter.GetText(PageIteratorLevel.Word);

                                        //WriteToTextFile(curText, symbolBounds, path);
                                        resultText.InnerText += curText;
                                        // Your code here, 'rect' should containt the location of the text, 'curText' contains the actual text itself
                                    }
                                } while (iter.Next(PageIteratorLevel.Word));
                            }


                            meanConfidenceLabel.InnerText = String.Format("{0:P}", page.GetMeanConfidence());

                        }
                    }
                }
            }

Here is an example of input and output showing the wrong spacing.

Answer 1

You can loop through found items in the page using page.GetIterator(). For the individual items you can get a 'bounding box', this is a Tesseract.Rect (rectangle struct) which contains: X1, Y1, X2, Y2 coordinates.

Tesseract.PageIteratorLevel myLevel = /*TODO*/;
using (var page = Engine.Process(img))
using (var iter = page.GetIterator())
{
    iter.Begin();
    do
    {
        if (iter.TryGetBoundingBox(myLevel, out var rect))
        {
            var curText = iter.GetText(myLevel);
            // Your code here, 'rect' should containt the location of the text, 'curText' contains the actual text itself
        }
    } while (iter.Next(myLevel));
}

---

There is no clear-cut way to use the positions in the input to space the text in the output. You're going to have to write some custom logic for that.

You might be able to estimate the number of spaces you need to the left of your text with something like this:

var padLeftSpaces = (int)Math.Round((rect.X1 / inputWidth) * outputWidthSpaces);