c# - region growing image segmentation -

i make region growing algorithm project algorithm

(my picture have been greyscale before it) 1. value pixel (0,0) seed pixel 2. compare value seed pixel 1 neighbor pixel 3. if value of no.3 less treshold (t), go next pixel , go no.2 4. if value of no.3 more treshold (t), change pixel white(also next 10 pixel), , new seed value pixel.

my goal picture segmented white line

this code

private void button4_click(object sender, eventargs e) { // gdi+ still lies - return format bgr, not rgb. bitmapdata bmdata = rimage.lockbits(new rectangle(0, 0, rimage.width, rimage.height), imagelockmode.readwrite, pixelformat.format24bpprgb);

        int stride = bmdata.stride;         system.intptr scan0 = bmdata.scan0;          unsafe         {             byte* p = (byte*)(void*)scan0;              int noffset = stride - rimage.width * 3;              (int y = 0; y < rimage.height; ++y)             {                                    (int x = 0; x < rimage.width; ++x)                 {                       //every new line of x must new seed                     if (x == 0)                     {                                                     //getting new value seed pixel                         seedr = p[x];                         seedg = p[x+1];                         seedb = p[x+2];                     }                      //compare value of seed pixel , pixel scan                     if ((seedr - p[x] >= tred) || (p[x] - seedr >= tred))                     {                          //make white line change value of pixel                         (int i=1; <= 5; ++i)                         {                             p[x] = p[x + 1] = p[x + 2] = 0;                             x++;                         }                          //getting new value of seed pixel                         seedr = p[x];                         seedg = p[x + 1];                         seedb = p[x + 2];                     }                     p += 3;                 }                 p += noffset;             }         }          rimage.unlockbits(bmdata);     } 

my problem image become white in 1/3 of image must doing "region growing" ?? thx

i've left questions algorithm in comments, writing them realized you're trying may not image segmentation @ all.

my goal picture segmented white line

do mean want this:

if yes, you're interested in isn't image segmentation, it's edge detection. if want implement that, have read convolution well.