c scan image to remove black edge of scanner to remove black edge

Automatically remove image scan black edge

/// <summary>
        ///  Automatically remove image scan black edge 
        /// </summary>
        /// <param name="fileName"></param>
        public static void AutoCutBlackEdge(string fileName)
        {
            // Open the image 
            Bitmap bmp = OpenImage(fileName);
            RemoveBlackEdge(bmp);
            // Save the image 
            SaveImage(bmp, fileName);
        }
        private static byte[] rgbValues; //  Target array memory 
        /// <summary>
        ///  The image goes black 
        /// </summary>
        /// <param name="bmp"></param>
        /// <returns></returns>
        private static Bitmap RemoveBlackEdge(Bitmap bmp)
        {
            Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
            BitmapData bmpData = bmp.LockBits(rect, ImageLockMode.ReadWrite, bmp.PixelFormat);
            //  Get image parameters   
            int w = bmpData.Width;
            int h = bmpData.Height;
            int stride = bmpData.Stride;  //  The width of the scan line  
            double picByteSize = GetPicByteSize(bmp.PixelFormat);
            int bWidth = (int)Math.Ceiling(picByteSize * w); // According to the width of the 
            int offset = stride - bWidth;  //  Shows the gap between width and scanline width   
            IntPtr ptr = bmpData.Scan0;   //  To obtain bmpData Is the starting location of memory   
            int scanBytes = stride * h;  //  with stride Width, which means this is the size of the memory area 
            //  Set two position Pointers, respectively, to the source and target arrays   
            int posScan = 0;
            rgbValues = new byte[scanBytes];  //  Allocates memory for the target array   
            Marshal.Copy(ptr, rgbValues, 0, scanBytes);  //  Copy image data to rgbValues In the   
            bool isPass = true;
            int i = 0, j = 0;
            int cutW = (int)(bWidth * 0.02); //2% Width (modifiable) 
            int cutH = (int)(h * 0.02);      //2% Height (modifiable) 
            int posLen = (int)(picByteSize * 8); // Keep looking for depth zero 8 Multiple of (modifiable) 
            // On the left 
            for (i = 0; i < h; i++)
            {
                for (j = 0; j < bWidth; j++)
                {
                    isPass = true;
                    if (rgbValues[posScan] < 255) rgbValues[posScan] = 255;
                    if (rgbValues[posScan + 1] == 255)
                    {
                        for (int m = 1; m <= posLen; m++)
                        {
                            if (rgbValues[posScan + m] < 255) isPass = false;
                        }
                    }
                    if (rgbValues[posScan + 1] < 255 || bWidth / 2 < j) isPass = false;
                    recCheck(ref rgbValues, posScan, h, stride, true);
                    posScan++;
                    if (j >= cutW && isPass) break;
                }
                //  Skipping bytes of unused space per line of image data, length = stride - width * bytePerPixel  
                if (j == bWidth) posScan += offset;
                else posScan += (offset + bWidth - j - 1);
            }
            // On the right 
            posScan = scanBytes - 1;
            for (i = h - 1; i >= 0; i--)
            {
                posScan -= offset;
                for (j = bWidth - 1; j >= 0; j--)
                {
                    isPass = true;
                    if (rgbValues[posScan] < 255) rgbValues[posScan] = 255;
                    if (rgbValues[posScan - 1] == 255)
                    {
                        for (int m = 1; m <= posLen; m++)
                        {
                            if (rgbValues[posScan - m] < 255) isPass = false;
                        }
                    }
                    if (rgbValues[posScan - 1] < 255 || bWidth / 2 > j) isPass = false;
                    recCheck(ref rgbValues, posScan, h, stride, false);
                    posScan--;
                    if (cutH < (h - i))
                        if (j < (bWidth - cutW) && isPass) break;
                }
                //  Skipping bytes of unused space per line of image data, length = stride - width * bytePerPixel
                if (j != -1) posScan -= j;
            }
            //  Memory to unlock   
            Marshal.Copy(rgbValues, 0, ptr, scanBytes);
            bmp.UnlockBits(bmpData);  //  Unlock memory area   
            return bmp;
        }
        /// <summary>
        ///  When the black edges are removed, the adjacent black spots are removed 
        /// </summary>
        /// <param name="rgbValues"></param>
        /// <param name="posScan"></param>
        /// <param name="h"></param>
        /// <param name="stride"></param>
        /// <param name="islLeft"></param>
        private static void recCheck(ref byte[] rgbValues, int posScan, int h, int stride, bool islLeft)
        {
            int scanBytes = h * stride;
            int cutH = (int)(h * 0.01); // Close to the biggest 1% Height (modifiable) 
            for (int i = 1; i <= cutH; i++)
            {
                int befRow = 0;
                if (islLeft && (posScan - stride * i) > 0)
                {
                    befRow = posScan - stride * i;
                }
                else if (!islLeft && (posScan + stride * i) < scanBytes)
                {
                    befRow = posScan + stride * i;
                }
                if (rgbValues[befRow] < 255) rgbValues[befRow] = 255;
                else break;
            }
        }