C#图像识别：判断图形是否存在于另一个图形中

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;

namespace BaiDu_C.BLL
{
    public class SearchImgPoint
    {
        /// <summary>  
        /// 判断图形里是否存在另外一个图形 并返回所在位置  
        /// </summary>  
        /// <param name="p_SourceBitmap">原始图形</param>  
        /// <param name="p_PartBitmap">小图形</param>  
        /// <param name="p_Float">溶差</param>  
        /// <returns>坐标</returns>  
        public static Point GetImageContains(Bitmap p_SourceBitmap, Bitmap p_PartBitmap, int p_Float,int point_num)
        {
            int _SourceWidth = p_SourceBitmap.Width;
            int _SourceHeight = p_SourceBitmap.Height;

            int _PartWidth = p_PartBitmap.Width;
            int _PartHeight = p_PartBitmap.Height;

            Bitmap _SourceBitmap = new Bitmap(_SourceWidth, _SourceHeight);
            Graphics _Graphics = Graphics.FromImage(_SourceBitmap);
            _Graphics.DrawImage(p_SourceBitmap, new Rectangle(0, 0, _SourceWidth, _SourceHeight));
            _Graphics.Dispose();