How to Identify OCR Needs in a Folder of PDFs

using pdftron; 
using pdftron.PDF; 
using pdftron.SDF; 

namespace ConsoleApp1 
{ 
    internal class Program 
    { 
        static void Main(string[] args) 
        { 
            PDFNet.Initialize(PDFTronLicense.License); 
            PDFNet.AddResourceSearchPath(PDFTronLicense.ModulePath); 
            string inputDir = @"path_to_input_dir"; 
            string outputDir = @"path_to_output_dir"; 
            foreach (string filePath in Directory.GetFiles(inputDir, "*.pdf")) 
            { 
                using (PDFDoc doc = new PDFDoc(filePath)) 
                { 
                    doc.InitSecurityHandler(); 
                    int textCount = 0; 
                    int nonTextCount = 0; 
                    ElementReader reader = new ElementReader(); 
                    for (int i = 1; i <= doc.GetPageCount(); i++) 
                    { 
                        pdftron.PDF.Page page = doc.GetPage(i); 
                        reader.Begin(page); 

                        Element element; 
                        while ((element = reader.Next()) != null) 
                        { 
                            switch (element.GetType()) 
                            { 
                                case Element.Type.e_text: 
                                    textCount++; 
                                    break; 
                                default: 
                                    nonTextCount++; 
                                    break; 
                            } 
                        } 
                        reader.End(); 
                    } 

                    int totalElements = textCount + nonTextCount; 
                    double nonTextPercentage = (double)nonTextCount / totalElements * 100; 

                    if (nonTextPercentage > 10) 
                    { 
                        OCRModule.ProcessPDF(doc, null); 
                        string outputFilePath = Path.Combine(outputDir, Path.GetFileName(filePath)); 
                        doc.Save(outputFilePath, SDFDoc.SaveOptions.e_linearized); 
                        Console.WriteLine($"OCR performed on {filePath} and saved to {outputFilePath}"); 
                    } 
                    else 
                    { 
                        Console.WriteLine($"No OCR needed for {filePath}"); 
                    } 
                } 
            } 
        } 
    } 
}