C#

            BitmapData bmpdata = AOIImg.LockBits(new Rectangle(0, 0, WIDTH, HEIGHT), ImageLockMode.ReadOnly, AOIImg.PixelFormat);
            IntPtr scan0 = bmpdata.Scan0;
            int stride = bmpdata.Stride;
            int imgOffs;
            try
            {
                //loop through the image and set the main AOI mask
                unsafe
                {
                    byte* imgPtr;
                    for (int y = 0; y < HEIGHT; ++y)
                    {
                        imgOffs = y * stride;
                        imgPtr = &((byte*)scan0)[imgOffs];
                        for (int x = 0; x < WIDTH; ++x)
                        {
                            //checks the blue, green, and red values of the pixel to see if it's black
                            if (imgPtr[0] == 0 && imgPtr[1] == 0 && imgPtr[2] == 0)
                            { //pixel is black -- exclude from aoi mask
                                AOIMask[y * WIDTH + x] = true;
                            }
                            else //no feature
                            {
                                AOIMask[y * WIDTH + x] = false;
                            }
                            imgPtr += 3; //advance ptr by 3 bytes (one pixel)
                        }

                    }
                }
            }
            finally 
            {
                AOIImg.UnlockBits(bmpdata);
#if DEBUG
                //TODO -- remove
                AOIImg.Save(@"C:\temp.png", ImageFormat.Png);
#endif
                AOIImg.Dispose();
            }