Form1 de textboxa yazılan değere butona tıkladığımda nasıl diğer classtan ulaşabilirim?

Yazdığım kodda Contrast.cs de textboxta(form1) girilen veriye ulaşmak istiyorum.Bunu nasıl yapabilirim?
Form1

using AForge.Video.DirectShow;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Drawing.Imaging;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace imageprocessing
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        public FilterInfoCollection devices;
        public VideoCaptureDevice camera;
        private void Form1_Load(object sender, EventArgs e)
        {
            devices = new FilterInfoCollection(FilterCategory.VideoInputDevice);
            foreach (FilterInfo item in devices)
            {
                cb_show.Items.Add(item.Name);

            }
            camera = new VideoCaptureDevice();
            cb_show.SelectedIndexChanged += cb_show_SelectedIndexChanged;
        }
        private void cb_show_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {
                if (camera.IsRunning == false)
                {
                    camera = new VideoCaptureDevice(devices[cb_show.SelectedIndex].MonikerString);
                    camera.NewFrame += Camera_NewFrame;
                    camera.Start();
                }
            }
            catch (Exception exc)
            {
                MessageBox.Show(exc.Message + "");
            }
        }
        List<byte> alldata = new List<byte>();
        public void Camera_NewFrame(object sender, AForge.Video.NewFrameEventArgs eventArgs)
        {
            Bitmap image = (Bitmap)eventArgs.Frame.Clone();
            byte[] maindata = new byte[image.Width * 3];

            if (btn_grayWasClicked == true)
            {
                alldata.Clear();
                for (int i = 0; i < image.Height; i++)
                {
                    int count = 0;
                    for (int j = 0; j < image.Width; j++)
                    {
                        Color color = image.GetPixel(j, i);
                        maindata[count] = color.R;
                        maindata[count + 1] = color.G;
                        maindata[count + 2] = color.B;
                        count += 3;
                    }
                    byte[] processGray = Gray.GrayFilter(maindata, image.Width);
                    alldata.AddRange(processGray);
                }
            }
           
        }
        private bool btn_contrastWasClicked = false;

        private void btn_contrast_Click(object sender, EventArgs e)
        {
            btn_contrastWasClicked = true;
        }

Contrast.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace imageprocessing
{
    class Contrast
    {
        public static byte[] Contrast(byte[] data, int width)
        {
            List<byte> alldataa = new List<byte>();
            double cont =(100.0 + (Convert.ToInt32()-100))/100.0)*(100.0 + (Convert.ToInt32() - 100)) / 100.0);
            for (int i = 0; i < width - 1; i += 3)
            {
                data[i]=((((data[i]/255)-0.5)*cont)+0.5)*255;
                if (data[i]<0)
                {
                    data[i] = 0;
                }
                if(data[i]>255)
                {
                    data[i] = 255;
                }
            }
            return data;
        }
    }
}

Textbox a girilen değer bu kısımda ConvertToInt32 nin içinde gerekiyor:

 double cont =(100.0 + (Convert.ToInt32()-100))/100.0)*(100.0 + (Convert.ToInt32() - 100)) / 100.0);