Unityスクリプトのスレッド処理について

前提・実現したいこと

unityのスクリプトで非同期処理をしています．
threadクラスを用いてサブスレッドの方でVideo()をメインスレッドの方でRealShadowMove()を実行しているのですがPlayボタンを押してアプリを実行するとEditorがフリーズしてしまいます
何が原因か教えていただけると助かります

該当のソースコード

言語はC#です

ソースコード
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Threading;
using OpenCvSharp;
using OpenCvSharp.Blob;
using System;
using System.IO;
public class sdaaasdf : MonoBehaviour
{
    private Thread _thread;
    private int i = 0;
    private Mat gameview;
    private Camera ConvertCamera;
    private Vector3 ScreenPt =new Vector3(0f,0f,0f);
    private Vector3 WorldPoint;
    private Vector3 MousePoint;
    void Start()
    {
        ConvertCamera = Camera.main;
        _thread = new Thread(Video);
        _thread.Start();
        _thread.Join();
        RealShadowMove();
    }

    void Video()
    {
        var frame = new Mat();
        var frame2 = new Mat();
        var gray = new Mat();
        var gray2 = new Mat();
        var binary = new Mat();
        var binary2 = new Mat();
        var diff = new Mat();
        var find = new Mat();
        var contours = new Mat[] { };
        var hierarchy = new Mat();
        var contours2 = new Mat[] { };
        var video0 = new VideoCapture(0);


        // var video1 = new VideoCapture(1);
        while (true)
        {
            //webカメラ画像読み込み
            video0.Read(frame);
            //画像処理
            binary = ImageProcessing(frame, 180);
            // ラベリング実行（必要な領域以外は排除）
            CvBlobs blobs = new CvBlobs(binary);
            blobs.FilterByArea(2000, 7000);
            for (int i = 1; i < blobs.Count; i++)
            {
                var cvContour = blobs[i].Contour;
                var L = cvContour.Perimeter();
                var area = blobs[i].Area;
                var circularity = 4 * Math.PI * (area / (L * L));
                if (0.4 < circularity && circularity < 0.9)
                {
                    blobs.FilterByLabel(i);
                    Debug.Log(circularity);
                }
            }
            // ラベリング結果の描画
            var render = new Mat(frame.Rows, frame.Cols, MatType.CV_8UC3, 3);
            blobs.RenderBlobs(frame, render);

            //切り抜き
            CvBlob maxBlob = blobs.LargestBlob();
            render = render[maxBlob.Rect];

            //ここまでウェブカメラ画像の処理

            //同様にしてゲームビュー画像の処理
            binary2 = ImageProcessing(gameview, 50);
            CvBlobs blobs2 = new CvBlobs(binary2);
            var render2 = new Mat(gameview.Rows, gameview.Cols, MatType.CV_8UC3, 3);
            blobs2.RenderBlobs(gameview, render2);
            CvBlob maxBlob2 = blobs2.LargestBlob();
            render2 = render2[maxBlob2.Rect];

            //画像拡大縮小
            Cv2.Resize(render, render, new OpenCvSharp.Size(render2.Width, render2.Height), 0, 0, InterpolationFlags.Cubic);


            //画像の差分計算
            Cv2.Absdiff(render, render2, diff);


            //実影の認識
            var binarydiff = ImageProcessing(diff, 150);
            CvBlobs diffblobs = new CvBlobs(binarydiff);
            var maxdiffblob = diffblobs.LargestBlob();
            //var realshadow= diff[maxBlob.Rect];
            //バウンディングボックス描画
            binarydiff.FindContours(out contours, hierarchy, RetrievalModes.List, ContourApproximationModes.ApproxNone);
            for (int i = 0; i < contours.Length; i++)
            {
                var Rect = Cv2.BoundingRect(contours[i]);
                Cv2.Rectangle(binarydiff, new Point(Rect.X, Rect.Y), new Point(Rect.X + Rect.Width, Rect.Y + Rect.Height), Scalar.Blue, 2);
            }
            //比率変換の係数計算
            var TransportWidth = (double)(Screen.width / binarydiff.Width);
            var TransportHeight = (double)(Screen.height / binarydiff.Height);

            Debug.Log("幅の比率:" + TransportWidth);
            Debug.Log("高さの比率:" + TransportHeight);
            Debug.Log(maxdiffblob.Area);
            if (maxdiffblob.Area > 10000)
            {
                var pt = maxdiffblob.Centroid;
                Debug.Log("実影の座標" + pt.X + "," + pt.Y);
                ScreenPt= new Vector3((float)(pt.X * TransportWidth), (float)(Screen.height - (pt.Y * TransportHeight)), 10.0f);
            }
            else
            {
                ScreenPt = new Vector3(-100f, -100f, -100f);
                Debug.Log("aaa");
            }

            //結果の表示
            using (new Window("binary", binary)) ;
            using (new Window("render", render)) ;
            using (new Window("render2", render2)) ;
            using (new Window("diff", diff)) ;
            using (var win = new Window("binarydiff", binarydiff)) ;

            //using (new Window("realshadow", realshadow));

            //キー入力処理
            int key = Cv2.WaitKey(100);
            if (key == 27) break;
            if (i == 1)
            {
                break;
            }
        }
    }
    //画像処理の関数(引数は画像,閾値k（0~255）)
    Mat ImageProcessing(Mat frame, int k)
    {
        var render = new Mat(frame.Rows, frame.Cols, MatType.CV_8UC3, 3);
        var gray = new Mat();
        var binary = new Mat();
        //グレースケール変換
        Cv2.CvtColor(frame, gray, ColorConversionCodes.BGR2GRAY);
        //平滑化
        Cv2.Blur(gray, gray, new Size(5, 5));
        //二値化
        binary = gray.Threshold(k, 255, ThresholdTypes.Binary);
        return binary;
    }

    //実影のオブジェクト移動，描画
    void RealShadowMove()
    {
        while (true)
        {
            ScreenCapture.CaptureScreenshot("image4.png");
            gameview = new Mat(@"image.png");
            Vector3 MousePos = Input.mousePosition;
            MousePos.z = 10.0f;
            Debug.Log("マウスの位置" + MousePos);
            Debug.Log("screen画面での実影の座標" + ScreenPt);
            WorldPoint = ConvertCamera.ScreenToWorldPoint(ScreenPt);
            MousePoint = ConvertCamera.ScreenToWorldPoint(MousePos);
            WorldPoint.y *= -1;
            MousePoint.y *= -1;
            //this.gameObject.transform.position = MousePoint;
            this.gameObject.transform.position = WorldPoint;
            iTween.MoveTo(this.gameObject, WorldPoint, (float)0.1);
            Debug.Log("実影のワールド座標" + WorldPoint);
            Debug.Log("マウスのワールド座標" + MousePoint);
            if (i == 1)
            {
                break;
            }
        }
    }
    // Update is called once per frame
    void Update(){}

    private void OnApplicationQuit()
    {
        if (_thread != null)
        {
            i = 1;
        }
    }
}


### 試したこと
while分の中で無限ループを起こしている可能性が高いと思い，キー入力で抜けるようにもしてみましたがうまくいかない状況です

### 補足情報（FW/ツールのバージョンなど）
OS:win10，Unity:2018.2.2f1 
ここにより詳細な情報を記載してください。