Hello to all, [INDENT]I am making an application which will only take images, convert it into binary image using a threshold. Now this binary image will be segmented horizontally on the basis of black pixels. In the attachment , this is the original image file. Now i have to segment it in these two segments i.e, and .

I am using the following code to do this, i am getting an exception ofinvalid parameters to the Rectangle in line 51 [/INDENT]
Please view the following code carefully and tell me the logical mistake please thanks in advance;

public ArrayList horizantalsegment()
        {

            ArrayList aa = new ArrayList();

            int counter = 0, x1 = 0, x2 =0, y1 =0, y2 =0;

            bool flagblack = false;

            Bitmap bitmap = new Bitmap(srcimage.Width, srcimage.Height);

            Bitmap bsegment = (Bitmap)srcimage.Clone ();

            BitmapData srcdata = ((Bitmap)srcimage).LockBits(new Rectangle(0, 0, srcimage.Width, srcimage.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);

            BitmapData destdata = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);

            byte clrvalue = 0;

            unsafe
            {
                for (int i = 0; i < srcdata.Height; i++)
                {
                    byte* ptr = (byte*)srcdata.Scan0 + (i * srcdata.Stride);
                    byte* dptr = (byte*)destdata.Scan0 + (i * srcdata.Stride);

                    for (int j = 0; j < srcdata.Width; j++)
                    {

                        clrvalue = 0;

                        clrvalue = (byte)(ptr[0] + ptr[1] + ptr[2]);

                        if (clrvalue == 0 && !flagblack)
                        {
                            y1 = i - 1;
                            flagblack = true;
                        }
                        else if (flagblack)
                        {
                            counter++;
                        }
                        

                        if (counter == srcimage.Width - 1)
                        {
                            y2 = y1 + i + 2;

                            Bitmap segmentedimg = new Bitmap(bsegment.Width, y2 - y1);
                            BitmapData segmentdata = segmentedimg.LockBits(new Rectangle(0, 0, bsegment.Width, segmentedimg.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
                            BitmapData srcdataseg = bsegment.LockBits(new Rectangle(0, y1, bsegment.Width, y2 -y1), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
                            
                            for (int x = 0  ; x < segmentedimg.Height;  x++)
                            {
                                byte* srcptr = (byte*)srcdataseg.Scan0 + (x * srcdataseg.Stride);
                                byte* segptr = (byte*)segmentdata.Scan0 + (x * segmentdata.Stride);

                                for (int y = y1; y < y2 ; y++)
                                {
                                    byte  color = (byte)((srcptr[0] + srcptr[1] + srcptr[2]) / 3);

                                    segptr[0] = segptr[1] = segptr[2] = color;

                                    srcptr += 3;
                                    segptr += 3;
                                    
                                }
                            }
                            x1 = 0;
                            x2 = 0;
                            y1 = 0;
                            y2 = 0;
                            flagblack = false;
                            segmentedimg.UnlockBits(segmentdata);
                            bsegment.UnlockBits(srcdataseg);
                            aa.Add(segmentedimg);
                            counter = 0;
                        }
                        ptr += 3;
                        dptr += 3;
                    }
                    counter = 0;
                }
            }

            ((Bitmap)srcimage).UnlockBits(srcdata);
            bitmap.UnlockBits(destdata);

            return aa;
        }

emarshah,
Rectangle coordinates must lie inside the bitmap. Use System.Runtime.InteropServices.Marshal.Copy method to copy bitmap value into an array (byte).

Hello,

I have locate the error, i wasn't clearing the variables x1, y1, x2 and y2.... Thanks for input.

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