So i’m trying to use IronOcr in .NET 5, and i’m having trouble understanding the coordinates it gives me.
Context: IronOcr is a Tesseract library. I’m using it to scan an image. The image is 688x688. I’m using the following code:
using System;
using System.IO;
using System.Linq;
using System.Collections.Generic;
using System.Drawing;
using IronOcr;
using System.Text.RegularExpressions;
namespace ScratchConsole
{
class Program
{
static void Main()
{
string file = @"a_valid_file_path.jpg";
Image saveme = Image.FromFile(file);
Graphics graphic = Graphics.FromImage(saveme); //This is for later manipulation of the original picture.
var tess = new IronTesseract();
using var Input = new OcrInput();
var ContentArea = new Rectangle() { X = 300, Y = 200, Height = 300, Width = 388 };
Input.AddImage(saveme, ContentArea);
tess.Configuration.TesseractVariables["classify_font_name"] = "Arial";
var res = tess.Read(Input);
string text = res.Text;
Console.WriteLine(text);
}
}
}
Note: I am limiting the scan area of the OCR with the rectangle, as shown in their example.
When i break at the Console.Writeline and inspect res, i can find the block that it found the line of text in (which is Blocks[1], or the second block). The Location of that block is:
res.Blocks[1].Location
{X = 1162 Y = 817 Width = 336 Height = 36}
Bottom: 853
Height: 36
IsEmpty: false
Left: 1162
Location: {X = 1162 Y = 817}
Right: 1498
Size: {Width = 336 Height = 36}
Top: 817
Width: 336
X: 1162
Y: 817
height: 36
width: 336
x: 1162
y: 817
the dimensions of this dont look right, and neither do the X/Y coordinates. The original image is only 688x688, so how is IronOCR finding a bounding box starting at 1162,817? The original text, if i bound it in MS Paint, is roughly 150x20, and is somewhere around 495, 347 as a top-left coordinate…
Am I missing something obvious? Is there some scaling factor somewhere that I can use to translate back to my original image? All i’m trying to do is create a bounding box around a regex-defined phrase (well, either one of a pair of phrases) in order to erase it from the original image…
