AIParkingApplication/AIParkingApplication/PlateProcessor.cs

using OpenCvSharp;
using OpenCvSharp.Extensions;
using System;
using System.Drawing;
using System.IO;
using System.Threading.Tasks;

namespace AIParkingApplication
{
    public class PlateProcessor
    {
        private bool isSupportSquarePlate;
        private bool isSupportLongPlate;
        private PlateDetector squarePlateDetector;
        private PlateDetector longPlateDetector;

        public PlateProcessor(bool isSupportSquarePlate = true, bool isSupportLongPlate = false)
        {
            this.isSupportSquarePlate = isSupportSquarePlate;
            this.isSupportLongPlate = isSupportLongPlate;

            if (this.isSupportSquarePlate)
            {
                squarePlateDetector = new PlateDetector(PlateType.Square, PlateDetectorConstant.MIN_SIZE_DEFAULT_SQUARE_PLATE, PlateDetectorConstant.MAX_SIZE_DEFAULT_SQUARE_PLATE, PlateDetectorConstant.SCALE_FACTOR_DEFAULT_SQUARE_PLATE, PlateDetectorConstant.MIN_NEIGHBORS_DEFAULT_SQUARE_PLATE);
            }

            if (this.isSupportLongPlate)
            {
                longPlateDetector = new PlateDetector(PlateType.Long, PlateDetectorConstant.MIN_SIZE_DEFAULT_LONG_PLATE, PlateDetectorConstant.MAX_SIZE_DEFAULT_LONG_PLATE, PlateDetectorConstant.SCALE_FACTOR_DEFAULT_LONG_PLATE, PlateDetectorConstant.MIN_NEIGHBORS_DEFAULT_LONG_PLATE);
            }
        }

        private async Task<FinalPlateResult> DetectPlateAndDoOcrEngineAsync(PlateType plateType, Mat frame)
        {
            Mat plateDetected = plateType == PlateType.Square ? squarePlateDetector.DetectPlate(frame) : longPlateDetector.DetectPlate(frame);

            //TODO: check size before resizing
            Cv2.Resize(plateDetected, plateDetected, new OpenCvSharp.Size(272, 272));

            //TODO: Check if plateDetected empty
            OcrResult plateOcrResultFromEngine = await Util.SendEngineRequestAsync(plateDetected, plateType);
            Bitmap finalPlateImage;
            if (!string.IsNullOrEmpty(plateOcrResultFromEngine.Ocr) && !string.IsNullOrEmpty(plateOcrResultFromEngine.Plate))
            {
                byte[] imageData = Convert.FromBase64String(plateOcrResultFromEngine.Plate);
                using (var ms = new MemoryStream(imageData))
                {
                    finalPlateImage = new Bitmap(ms);
                }
            }
            else
            {
                finalPlateImage = plateDetected.ToBitmap();
            }

            return new FinalPlateResult
            {
                PlateString = plateOcrResultFromEngine.Ocr,
                PlateImage = finalPlateImage
            };
        }

        public async Task<FinalPlateResult> ProcessPlate(Mat frame)
        {
            try
            {
                //TODO: check size before resizing
                Cv2.Resize(frame, frame, new OpenCvSharp.Size(1280, 720));
                FinalPlateResult plateResult;

                if (isSupportLongPlate)
                {
                    plateResult = await DetectPlateAndDoOcrEngineAsync(PlateType.Long, frame);
                    if (!IsPlateStringValid(plateResult.PlateString))
                    {
                        plateResult = await DetectPlateAndDoOcrEngineAsync(PlateType.Square, frame);
                    }
                }
                else
                {
                    Console.WriteLine("Recall Square Plates");
                    plateResult = await DetectPlateAndDoOcrEngineAsync(PlateType.Square, frame);
                }

                return plateResult;
            }
            catch (Exception ex)
            {
                Console.WriteLine($"{Util.GetCurrentMethodName()}\texMessage: {ex.Message}");
                return new FinalPlateResult();
            }
        }

        //TODO: Complete this
        private string NormalizePlateString(string plateString)
        {
            return plateString;
        }

        public bool IsPlateStringValid(string plateString, int minPlateStringLength = 5)
        {
            bool isValid = !string.IsNullOrEmpty(plateString) && plateString.Length > minPlateStringLength;
            return isValid;
        }
    }

    public class FinalPlateResult
    {
        public string PlateString { get; set; }
        public Bitmap PlateImage { get; set; }
    }
}