C# 如何在一張大圖片中快速找到另外一張圖片（兩種方式）？

　　自己寫了一種，速度不是很快，但是能夠實現

　　　　　　　var findpic = new FindPic();
            var rec = findpic.FindPicture(@"C:\Users\zaranet\Desktop\xiao.png", @"C:\Users\zaranet\Desktop\da.png", 10);
            MessageBox.Show(rec[0].X +","+rec[0].Y);

Find類，在這其中先刪除了最外邊界的高寬，最後註意迴圈足夠rate則直接返回。

    class FindPic
    {
        #region 找圖
        /// <summary>
        /// 查找圖片，不能鏤空
        /// </summary>
        /// <param name="subPic">要查找坐標的小圖</param>
        /// <param name="parPic">在哪個大圖裡查找</param>
        /// <param name="errorRange">容錯，單個色值範圍內視為正確0~255</param>
        /// <param name="searchRect">如果為empty，則預設查找整個圖像</param>
        /// <param name="matchRate">圖片匹配度，預設90%</param>
        /// <param name="isFindAll">是否查找所有相似的圖片</param>
        /// <returns>返回查找到的圖片的中心點坐標</returns>
        public List<System.Drawing.Point> FindPicture(string subPic, string parPic, byte errorRange = 0, Rectangle searchRect = new System.Drawing.Rectangle(), double matchRate = 0.9, bool isFindAll = false)
        {
            List<System.Drawing.Point> ListPoint = new List<System.Drawing.Point>();
            var subBitmap = new Bitmap(subPic);
            var parBitmap = new Bitmap(parPic);
            int subWidth = subBitmap.Width;
            int subHeight = subBitmap.Height;
            int parWidth = parBitmap.Width;
            int parHeight = parBitmap.Height;
            if (searchRect.IsEmpty)
            {
                searchRect = new Rectangle(0, 0, parBitmap.Width, parBitmap.Height);
            }
            var searchLeftTop = searchRect.Location;
            var searchSize = searchRect.Size;
            System.Drawing.Color startPixelColor = subBitmap.GetPixel(0, 0);
            var subData = subBitmap.LockBits(new Rectangle(0, 0, subBitmap.Width, subBitmap.Height), ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
            var parData = parBitmap.LockBits(new Rectangle(0, 0, parBitmap.Width, parBitmap.Height), ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
            var byteArrarySub = new byte[subData.Stride * subData.Height];
            var byteArraryPar = new byte[parData.Stride * parData.Height];
            Marshal.Copy(subData.Scan0, byteArrarySub, 0, subData.Stride * subData.Height);
            Marshal.Copy(parData.Scan0, byteArraryPar, 0, parData.Stride * parData.Height);
            var iMax = searchLeftTop.Y + searchSize.Height - subData.Height;//行
            var jMax = searchLeftTop.X + searchSize.Width - subData.Width;//列
            int smallOffsetX = 0, smallOffsetY = 0;
            int smallStartX = 0, smallStartY = 0;
            int pointX = -1; int pointY = -1;
            for (int i = searchLeftTop.Y; i < iMax; i++)
            {
                for (int j = searchLeftTop.X; j < jMax; j++)
                {
                    //大圖x，y坐標處的顏色值
                    int x = j, y = i;
                    int parIndex = i * parWidth * 4 + j * 4;
                    var colorBig = System.Drawing.Color.FromArgb(byteArraryPar[parIndex + 3], byteArraryPar[parIndex + 2], byteArraryPar[parIndex + 1], byteArraryPar[parIndex]);
                    ;
                    if (ColorAEqualColorB(colorBig, startPixelColor, errorRange))
                    {
                        smallStartX = x - smallOffsetX;//待找的圖X坐標
                        smallStartY = y - smallOffsetY;//待找的圖Y坐標
                        int sum = 0;//所有需要比對的有效點
                        int matchNum = 0;//成功匹配的點
                        for (int m = 0; m < subHeight; m++)
                        {
                            for (int n = 0; n < subWidth; n++)
                            {
                                int x1 = n, y1 = m;
                                int subIndex = m * subWidth * 4 + n * 4;
                                var color = System.Drawing.Color.FromArgb(byteArrarySub[subIndex + 3], byteArrarySub[subIndex + 2], byteArrarySub[subIndex + 1], byteArrarySub[subIndex]);
                                sum++;
                                int x2 = smallStartX + x1, y2 = smallStartY + y1;
                                int parReleativeIndex = y2 * parWidth * 4 + x2 * 4;//比對大圖對應的像素點的顏色
                                var colorPixel = System.Drawing.Color.FromArgb(byteArraryPar[parReleativeIndex + 3], byteArraryPar[parReleativeIndex + 2], byteArraryPar[parReleativeIndex + 1], byteArraryPar[parReleativeIndex]);
                                if (ColorAEqualColorB(colorPixel, color, errorRange))
                                {
                                    matchNum++;
                                }
                            }
                        }
                        if ((double)matchNum / sum >= matchRate)
                        {
                            Console.WriteLine((double)matchNum / sum);
                            pointX = smallStartX + (int)(subWidth / 2.0);
                            pointY = smallStartY + (int)(subHeight / 2.0);
                            var point = new System.Drawing.Point(pointX, pointY);
                            if (!ListContainsPoint(ListPoint, point, 10))
                            {
                                ListPoint.Add(point);
                            }
                            if (!isFindAll)
                            {
                                goto FIND_END;
                            }
                        }
                    }
                    //小圖x1,y1坐標處的顏色值
                }
            }
        FIND_END:
            subBitmap.UnlockBits(subData);
            parBitmap.UnlockBits(parData);
            subBitmap.Dispose();
            parBitmap.Dispose();
            GC.Collect();
            return ListPoint;
        }
        #endregion
        public bool ColorAEqualColorB(System.Drawing.Color colorA, System.Drawing.Color colorB, byte errorRange = 10)
        {
            return colorA.A <= colorB.A + errorRange && colorA.A >= colorB.A - errorRange &&
                colorA.R <= colorB.R + errorRange && colorA.R >= colorB.R - errorRange &&
                colorA.G <= colorB.G + errorRange && colorA.G >= colorB.G - errorRange &&
                colorA.B <= colorB.B + errorRange && colorA.B >= colorB.B - errorRange;
        }
        public bool ListContainsPoint(List<System.Drawing.Point> listPoint, System.Drawing.Point point, double errorRange = 10)
        {
            bool isExist = false;
            foreach (var item in listPoint)
            {
                if (item.X <= point.X + errorRange && item.X >= point.X - errorRange && item.Y <= point.Y + errorRange && item.Y >= point.Y - errorRange)
                {
                    isExist = true;
                }
            }
            return isExist;
        }
    }

最後項目實施發現速度不快，只能棄用，網上查詢 發現有AForge實現方式。引用

private void button3_Click(object sender, EventArgs e)
        {
            System.Drawing.Bitmap sourceImage = ConvertToFormat(System.Drawing.Image.FromFile(@"C:\Users\zaranet\Desktop\da.png"), PixelFormat.Format24bppRgb);
            System.Drawing.Bitmap template = ConvertToFormat(System.Drawing.Image.FromFile(@"C:\Users\zaranet\Desktop\xiao.png"), PixelFormat.Format24bppRgb); 
            // create template matching algorithm's instance
            // (set similarity threshold to 92.5%)

            ExhaustiveTemplateMatching tm = new ExhaustiveTemplateMatching(0.921f);
            // find all matchings with specified above similarity

            TemplateMatch[] matchings = tm.ProcessImage(sourceImage, template);
            // highlight found matchings

            BitmapData data = sourceImage.LockBits(
                new Rectangle(0, 0, sourceImage.Width, sourceImage.Height),
                ImageLockMode.ReadWrite, sourceImage.PixelFormat);
            foreach (TemplateMatch m in matchings)
            {

                Drawing.Rectangle(data, m.Rectangle, Color.White);

                MessageBox.Show(m.Rectangle.Location.ToString());
                // do something else with matching
            }
            sourceImage.UnlockBits(data);
        }
        public Bitmap ConvertToFormat(System.Drawing.Image image, PixelFormat format)
        {
            Bitmap copy = new Bitmap(image.Width, image.Height, format);
            using (Graphics gr = Graphics.FromImage(copy))
            {
                gr.DrawImage(image, new Rectangle(0, 0, copy.Width, copy.Height));
            }
            return copy;
        }

速度略快吧。