using OpenCvSharp;
using System;

namespace ImageOcr
{
    class Program
    {
        static void Main(string[] args)
        {
            Mat img = new Mat();
            img = Cv2.ImRead("F:/IMG_20200927_150909.jpg");
            Cv2.ImShow("src", img);
            Mat grayImage = new Mat();
            Cv2.CvtColor(img, grayImage, ColorConversionCodes.BGR2GRAY);
            var Width= grayImage.Width;
            var Height = grayImage.Height;
            Mat binaryImage = new Mat();
            Cv2.AdaptiveThreshold(grayImage, binaryImage,255, AdaptiveThresholdTypes.GaussianC, ThresholdTypes.Binary,35,10);
            Cv2.ImShow("binaryImage", binaryImage);
            Mat hierarchy = new Mat();
            Cv2.FindContours(binaryImage,out Mat[] contours, hierarchy, RetrievalModes.Tree, ContourApproximationModes.ApproxSimple);
            Cv2.DrawContours(img, contours, 0, new Scalar(0,0,255),1);
            Cv2.ImShow("imgray", img);
            foreach (var i in contours) {
                double arclen = Cv2.ArcLength( i, true);
                double epsilon = Math.Max(2, arclen * 0.02);
                Mat approx = new Mat();
                Cv2.ApproxPolyDP(i, approx, epsilon, true);
                double area =Cv2.ContourArea(i);
                Console.WriteLine("面积：" + area);
                RotatedRect rect = Cv2.MinAreaRect(i);
                Console.WriteLine("rect：" + rect);
                Point2f[] re= Cv2.BoxPoints(rect);
                var w = re[1].X;
                var h = re[1].Y;
                var rotion = 0F;
                if (Math.Min(h, w) == 0)
                {
                    rotion = 0;
                }
                else {
                    rotion = Math.Max(h, w) / Math.Min(h, w);
                }
                var imageArea = Width * Height;
                if(rotion<10  && area>imageArea*0.2  && area< Width* Height * 0.99 && approx==4)
            }
        }
    }
}