private void LoadGrid(String filename)
{
if (File.Exists(filename))
{
stopwatch grid_timer = new stopwatch();
// read the data into a byte array
grid_timer.Start();
Byte[] grid_data = File.ReadAllBytes(filename);
grid_timer.Stop();
lstBenchmarks.Items.Add("Disk read time " + Convert.ToString(grid_timer.time_elapsed_mS) + " mS");
// decompress the data
grid_timer.Start();
Byte[] decompressed_grid_data =
AcedInflator.Instance.Decompress(grid_data, 0, 0, 0);
grid_timer.Stop();
lstBenchmarks.Items.Add("Decompression time " + Convert.ToString(grid_timer.time_elapsed_mS) + " mS");
grid_timer.Start();
sim.rob.LoadGrid(decompressed_grid_data);
grid_timer.Stop();
lstBenchmarks.Items.Add("Creation time " + Convert.ToString(grid_timer.time_elapsed_mS) + " mS");
}
}
/// <summary>
/// save the occupancy grid to file and show some benchmarks
/// </summary>
/// <param name="filename"></param>
private void SaveGrid(String filename)
{
FileStream fp = new FileStream(filename, FileMode.Create);
BinaryWriter binfile = new BinaryWriter(fp);
lstBenchmarks.Items.Clear();
stopwatch grid_timer = new stopwatch();
grid_timer.Start();
Byte[] grid_data = sim.rob.SaveGrid();
grid_timer.Stop();
lstBenchmarks.Items.Add("Distillation time " + Convert.ToString(grid_timer.time_elapsed_mS) + " mS");
grid_timer.Start();
Byte[] compressed_grid_data =
AcedDeflator.Instance.Compress(grid_data, 0, grid_data.Length,
AcedCompressionLevel.Fast, 0, 0);
grid_timer.Stop();
lstBenchmarks.Items.Add("Compression ratio " + Convert.ToString(100 - (int)(compressed_grid_data.Length * 100 / grid_data.Length)) + " %");
lstBenchmarks.Items.Add("Compression time " + Convert.ToString(grid_timer.time_elapsed_mS) + " mS");
grid_timer.Start();
binfile.Write(compressed_grid_data);
grid_timer.Stop();
lstBenchmarks.Items.Add("Disk write time " + Convert.ToString(grid_timer.time_elapsed_mS) + " mS");
binfile.Close();
fp.Close();
}
/// <summary>
/// update the robot's map
/// </summary>
/// <param name="state">robot state</param>
private static void Update(ThreadMappingState state)
{
// object used for taking benchmark timings
stopwatch clock = new stopwatch();
clock.Start();
// update all current poses with the observed rays
state.motion.LocalGrid = state.grid;
state.motion.AddObservation(state.stereo_rays, false);
clock.Stop();
state.benchmark_observation_update = clock.time_elapsed_mS;
// what's the relative position of the robot inside the grid ?
pos3D relative_position = new pos3D(state.pose.x - state.grid.x, state.pose.y - state.grid.y, 0);
relative_position.pan = state.pose.pan - state.grid.pan;
clock.Start();
// garbage collect dead occupancy hypotheses
state.grid.GarbageCollect();
clock.Stop();
state.benchmark_garbage_collection = clock.time_elapsed_mS;
}
/// <summary>
/// detects square shapes within the given mono image
/// </summary>
/// <param name="img_mono">
/// mono image data <see cref="System.Byte"/>
/// </param>
/// <param name="img_width">
/// image width <see cref="System.Int32"/>
/// </param>
/// <param name="img_height">
/// image height <see cref="System.Int32"/>
/// </param>
/// <param name="ignore_periphery">
/// whether to ignore edge features which stray into the border of the image <see cref="System.Boolean"/>
/// </param>
/// <param name="image_border_percent">
/// percentage of the image considred to be the surrounding border <see cref="System.Int32"/>
/// </param>
/// <param name="grouping_radius_percent">
/// radius used to group adjacent edge features <see cref="System.Int32"/>
/// </param>
/// <param name="erosion_dilation">
/// erosion dilation level <see cref="System.Int32"/>
/// </param>
/// <param name="black_on_white">
/// whether this image contains dark markings on a lighter background <see cref="System.Boolean"/>
/// </param>
/// <param name="minimum_volume_percent">
/// minimum volume of the square as a percentage of the image volume (prevents very small stuff being detected) <see cref="System.Int32"/>
/// </param>
/// <param name="use_original_image">
/// whether to allow img_mono to be altered
/// </param>
/// <param name="minimum_aspect_ratio">
/// minimum aspect ratio when searching for valid regions
/// </param>
/// <param name="maximum_aspect_ratio">
/// maximum aspect ratio when searching for valid regions
/// </param>
/// <returns>
/// list of polygons representing the square regions <see cref="List`1"/>
/// </returns>
public static List<polygon2D> DetectSquaresMono(byte[] mono_img,
int img_width, int img_height,
bool ignore_periphery,
int image_border_percent,
int[] grouping_radius_percent,
int[] erosion_dilation,
bool black_on_white,
int minimum_volume_percent,
bool use_original_image,
float minimum_aspect_ratio,
float maximum_aspect_ratio,
bool squares_only,
bool debug,
int circular_ROI_radius,
ref List<int> edges)
{
#if SHOW_TIMINGS
stopwatch timer_square_detection = new stopwatch();
timer_square_detection.Start();
#endif
const int minimum_size_percent = 5;
const int connect_edges_radius = 5;
// maximum recursion depth when joining edges
const int max_search_depth = 8000;
// create a list to store the results
List<polygon2D> square_shapes = new List<polygon2D>();
// create edge detection object
CannyEdgeDetector edge_detector = new CannyEdgeDetector();
edge_detector.automatic_thresholds = true;
edge_detector.enable_edge_orientations = false;
#if SHOW_TIMINGS
stopwatch timer_copy_invert = new stopwatch();
timer_copy_invert.Start();
#endif
byte[] img_mono = mono_img;
if (!use_original_image)
{
// make a copy of the original image (we don't want to alter it)
img_mono = (byte[])mono_img.Clone();
}
// if the image contains light markings on a darker background invert the pixels
if (!black_on_white)
{
for (int i = img_mono.Length-1; i >= 0; i--)
{
img_mono[i] = (byte)(255 - img_mono[i]);
}
}
#if SHOW_TIMINGS
timer_copy_invert.Stop();
if (timer_copy_invert.time_elapsed_mS > 20)
Console.WriteLine("DetectSquaresMono: copy/invert " + timer_copy_invert.time_elapsed_mS.ToString() );
#endif
int image_border = img_width * image_border_percent / 100;
byte[] img_mono2 = null;
byte[] eroded = null;
byte[] dilated = null;
bool previous_eroded = false;
bool previous_dilated = false;
// try each erosion/dilation level
for (int erosion_dilation_level = 0; erosion_dilation_level < erosion_dilation.Length; erosion_dilation_level++)
{
#if SHOW_TIMINGS
stopwatch timer_erode_dilate = new stopwatch();
timer_erode_dilate.Start();
#endif
// erode
if (erosion_dilation[erosion_dilation_level] > 0)
{
if (previous_eroded)
eroded = image.Erode(eroded, img_width, img_height,
erosion_dilation[erosion_dilation_level] - erosion_dilation[erosion_dilation_level-1],
eroded);
else
eroded = image.Erode(img_mono, img_width, img_height,
erosion_dilation[erosion_dilation_level],
null);
img_mono2 = eroded;
previous_eroded = true;
}
// dilate
if (erosion_dilation[erosion_dilation_level] < 0)
{
if (previous_dilated)
dilated = image.Dilate(dilated, img_width, img_height,
-erosion_dilation[erosion_dilation_level] + erosion_dilation[erosion_dilation_level-1],
dilated);
else
dilated = image.Dilate(img_mono, img_width, img_height,
-erosion_dilation[erosion_dilation_level],
null);
img_mono2 = dilated;
previous_dilated = true;
}
// just copy the original image
if (erosion_dilation[erosion_dilation_level] == 0)
{
if (erosion_dilation_level > 0)
img_mono2 = (byte[])img_mono.Clone();
else
img_mono2 = img_mono;
previous_eroded = false;
previous_dilated = false;
}
#if SHOW_TIMINGS
timer_erode_dilate.Stop();
if (timer_erode_dilate.time_elapsed_mS > 20)
Console.WriteLine("DetectSquaresMono: erode/dilate " + timer_erode_dilate.time_elapsed_mS.ToString() );
stopwatch timer_edge_detection = new stopwatch();
timer_edge_detection.Start();
#endif
// detect edges using canny algorithm
edge_detector.Update(img_mono2, img_width, img_height);
#if SHOW_TIMINGS
timer_edge_detection.Stop();
if (timer_edge_detection.time_elapsed_mS > 20)
Console.WriteLine("DetectSquaresMono: edge detect " + timer_edge_detection.time_elapsed_mS.ToString() );
#endif
if (debug)
{
string filename = "canny_magnitudes_" + erosion_dilation_level.ToString() + ".bmp";
byte[] magnitudes = new byte[img_width * img_height * 3];
edge_detector.ShowMagnitudes(magnitudes, img_width, img_height);
Bitmap magnitudes_bmp = new Bitmap(img_width, img_height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
BitmapArrayConversions.updatebitmap_unsafe(magnitudes, magnitudes_bmp);
magnitudes_bmp.Save(filename, System.Drawing.Imaging.ImageFormat.Bmp);
}
#if SHOW_TIMINGS
stopwatch timer_edge_joining = new stopwatch();
timer_edge_joining.Start();
#endif
// connect edges which are a short distance apart
edge_detector.ConnectBrokenEdges(connect_edges_radius);
#if SHOW_TIMINGS
timer_edge_joining.Stop();
if (timer_edge_joining.time_elapsed_mS > 20)
Console.WriteLine("DetectSquaresMono: edge joining " + timer_edge_joining.time_elapsed_mS.ToString() );
#endif
// remove edges which are outside a circular region of interest
if (circular_ROI_radius > 0)
{
int circular_ROI_radius_sqr = circular_ROI_radius * circular_ROI_radius;
int half_width = img_width / 2;
int half_height = img_height / 2;
for (int i = edge_detector.edges.Count - 2; i >= 0; i -= 2)
{
int x = edge_detector.edges[i];
int y = edge_detector.edges[i+1];
int dx = x - half_width;
int dy = y - half_height;
int dist_sqr = (dx*dx)+(dy*dy);
if (dist_sqr > circular_ROI_radius_sqr)
{
edge_detector.edges.RemoveAt(i+1);
edge_detector.edges.RemoveAt(i);
}
}
}
edges = edge_detector.edges;
// try different groupings
for (int group_radius_index = 0; group_radius_index < grouping_radius_percent.Length; group_radius_index++)
{
#if SHOW_TIMINGS
stopwatch timer_grouping = new stopwatch();
timer_grouping.Start();
stopwatch timer_perim2 = new stopwatch();
timer_perim2.Start();
#endif
// group edges together into objects
List<List<int>> groups =
GetGroups(edge_detector.edges,
img_width, img_height, image_border,
minimum_size_percent,
false, max_search_depth, ignore_periphery,
grouping_radius_percent[group_radius_index]);
#if SHOW_TIMINGS
timer_grouping.Stop();
if (timer_grouping.time_elapsed_mS > 20)
Console.WriteLine("DetectSquaresMono: edge grouping " + timer_grouping.time_elapsed_mS.ToString() );
#endif
if (groups != null)
{
#if SHOW_TIMINGS
stopwatch timer_aspect = new stopwatch();
timer_aspect.Start();
#endif
//List<List<int>> squares = groups;
// get the set of edges with aspect ratio closest to square
List<List<int>> squares = GetValidGroups(groups,
img_width, img_height,
//minimum_aspect_ratio, maximum_aspect_ratio,
minimum_size_percent);
#if SHOW_TIMINGS
timer_grouping.Stop();
if (timer_aspect.time_elapsed_mS > 20)
Console.WriteLine("DetectSquaresMono: aspect checking " + timer_aspect.time_elapsed_mS.ToString() );
#endif
if (squares != null)
{
for (int i = 0; i < squares.Count; i++)
{
#if SHOW_TIMINGS
stopwatch timer_periphery = new stopwatch();
timer_periphery.Start();
#endif
List<int> square = squares[i];
polygon2D perim = null;
List<List<int>> periphery = GetSquarePeriphery(square, erosion_dilation[erosion_dilation_level], ref perim);
#if SHOW_TIMINGS
timer_periphery.Stop();
//if (timer_periphery.time_elapsed_mS > 20)
Console.WriteLine("DetectSquaresMono: periphery detect " + timer_periphery.time_elapsed_mS.ToString() );
#endif
if (perim != null)
{
float longest_side = perim.getLongestSide();
float shortest_side = perim.getShortestSide();
// not too small
if (shortest_side * 100 / img_width > minimum_volume_percent)
{
float aspect = shortest_side / longest_side;
if ((aspect > minimum_aspect_ratio) &&
(aspect < maximum_aspect_ratio))
{
// check the angles
bool angle_out_of_range = false;
int vertex = 0;
while ((vertex < perim.x_points.Count) &&
(!angle_out_of_range) && (vertex < 4))
{
float angle = perim.GetInteriorAngle(vertex);
angle = angle / (float)Math.PI * 180;
if ((angle < 70) || (angle > 110)) angle_out_of_range = true;
vertex++;
}
if (!angle_out_of_range)
{
float aspect1 = perim.getSideLength(0) / perim.getSideLength(2);
if ((aspect1 > 0.9f) && (aspect1 < 1.1f))
{
float aspect2 = perim.getSideLength(1) / perim.getSideLength(3);
if ((aspect2 > 0.9f) && (aspect2 < 1.1f))
square_shapes.Add(perim);
}
}
}
}
}
}
}
}
#if SHOW_TIMINGS
timer_perim2.Stop();
if (timer_perim2.time_elapsed_mS > 20)
Console.WriteLine("DetectSquaresMono: grouping and periphery " + timer_perim2.time_elapsed_mS.ToString());
#endif
}
}
// remove any overlapping squares
square_shapes = SelectSquares(square_shapes, 0);
#if SHOW_TIMINGS
timer_square_detection.Stop();
if (timer_square_detection.time_elapsed_mS > 20)
Console.WriteLine("DetectSquaresMono: " + timer_square_detection.time_elapsed_mS.ToString() );
#endif
return(square_shapes);
}
/// <summary>
/// returns a polygon representing the periphery of a square region
/// </summary>
/// <param name="edges">
/// edges within the square region <see cref="List`1"/>
/// </param>
/// <param name="erode_dilate">
/// erosion or dilation level <see cref="System.Int32"/>
/// </param>
/// <param name="perim">
/// returned periphery <see cref="polygon2D"/>
/// </param>
/// <returns>
/// set of edges around the periphery <see cref="List`1"/>
/// </returns>
private static List<List<int>> GetSquarePeriphery(List<int> edges,
int erode_dilate,
ref polygon2D perim)
{
List<List<int>> result = new List<List<int>>();
perim = new polygon2D();
// find the bounding box for all edges
int tx = 99999;
int ty = 99999;
int bx = -99999;
int by = -99999;
for (int i = edges.Count-2; i >= 0; i -= 2)
{
int x = edges[i];
int y = edges[i+1];
if (x < tx) tx = x;
if (y < ty) ty = y;
if (x > bx) bx = x;
if (y > by) by = y;
}
int w = bx - tx;
int h = by - ty;
if ((w > 0) && (h > 0))
{
int[] left = new int[h+1];
int[] right = new int[h+1];
int[] top = new int[w+1];
int[] bottom = new int[w+1];
for (int i = edges.Count - 2; i >= 0; i -= 2)
{
int x = edges[i];
int x2 = x - tx;
int y = edges[i+1];
int y2 = y - ty;
// left side
if ((left[y2] == 0) ||
(x < left[y2]))
left[y2] = x;
// right side
if ((right[y2] == 0) ||
(x > right[y2]))
right[y2] = x;
// top
if ((top[x2] == 0) ||
(y < top[x2]))
top[x2] = y;
// bottom
if ((bottom[x2] == 0) ||
(y > bottom[x2]))
bottom[x2] = y;
}
#if SHOW_TIMINGS
stopwatch timer_best_fit = new stopwatch();
timer_best_fit.Start();
#endif
// find a best fit line for the left side
int best_start = 0;
int best_end = 0;
int hits = BestFitLine(left, ref best_start, ref best_end);
float left_x0 = left[best_start];
float left_y0 = ty + best_start;
float left_x1 = left[best_end];
float left_y1 = ty + best_end;
/*
BestFitLineAverage(left,
ref left_x0, ref left_y0,
ref left_x1, ref left_y1);
left_y0 += ty;
left_y1 += ty;
*/
// find a best fit line for the right side
best_start = 0;
best_end = 0;
hits = BestFitLine(right, ref best_start, ref best_end);
float right_x0 = right[best_start];
float right_y0 = ty + best_start;
float right_x1 = right[best_end];
float right_y1 = ty + best_end;
/*
BestFitLineAverage(right,
ref right_x0, ref right_y0,
ref right_x1, ref right_y1);
right_y0 += ty;
right_y1 += ty;
*/
// find a best fit line for the top side
best_start = 0;
best_end = 0;
hits = BestFitLine(top, ref best_start, ref best_end);
float top_x0 = tx + best_start;
float top_y0 = top[best_start];
float top_x1 = tx + best_end;
float top_y1 = top[best_end];
/*
BestFitLineAverage(top,
ref top_x0, ref top_y0,
ref top_x1, ref top_y1);
top_x0 += tx;
top_x1 += tx;
*/
// find a best fit line for the bottom side
best_start = 0;
best_end = 0;
hits = BestFitLine(bottom, ref best_start, ref best_end);
float bottom_x0 = tx + best_start;
float bottom_y0 = bottom[best_start];
float bottom_x1 = tx + best_end;
float bottom_y1 = bottom[best_end];
/*
BestFitLineAverage(bottom,
ref bottom_x0, ref bottom_y0,
ref bottom_x1, ref bottom_y1);
bottom_x0 += tx;
bottom_x1 += tx;
*/
#if SHOW_TIMINGS
timer_best_fit.Stop();
if (timer_best_fit.time_elapsed_mS > 20)
Console.WriteLine("GetSquarePeriphery: best fit " + timer_best_fit.time_elapsed_mS.ToString() );
#endif
// find the intersection between the left side and the top side
float ix=0;
float iy = 0;
geometry.intersection(left_x1, left_y1, left_x0, left_y0,
top_x1, top_y1, top_x0, top_y0,
ref ix, ref iy);
perim.Add(ix, iy);
// find the intersection between the right side and the top side
ix = 0;
iy = 0;
geometry.intersection(right_x1, right_y1, right_x0, right_y0,
top_x0, top_y0, top_x1, top_y1,
ref ix, ref iy);
perim.Add(ix, iy);
// find the intersection between the right side and the bottom side
ix = 0;
iy = 0;
geometry.intersection(right_x1, right_y1, right_x0, right_y0,
bottom_x0, bottom_y0, bottom_x1, bottom_y1,
ref ix, ref iy);
perim.Add(ix, iy);
// find the intersection between the left side and the bottom side
ix = 0;
iy = 0;
geometry.intersection(left_x1, left_y1, left_x0, left_y0,
bottom_x0, bottom_y0, bottom_x1, bottom_y1,
ref ix, ref iy);
perim.Add(ix, iy);
// left and right
List<int> left_edges = new List<int>();
List<int> right_edges = new List<int>();
for (int y = h; y >= 0; y--)
{
if (left[y] != 0)
{
left_edges.Add(left[y]);
left_edges.Add(ty + y);
}
if (right[y] != 0)
{
right_edges.Add(right[y]);
right_edges.Add(ty + y);
}
}
// top and bottom
List<int> top_edges = new List<int>();
List<int> bottom_edges = new List<int>();
for (int x = w; x >= 0; x--)
{
if (top[x] != 0)
{
top_edges.Add(tx + x);
top_edges.Add(top[x]);
}
if (bottom[x] != 0)
{
bottom_edges.Add(tx + x);
bottom_edges.Add(bottom[x]);
}
}
float aspect_check = perim.getShortestSide() / perim.getLongestSide();
if (aspect_check > 0.2f)
{
result.Add(left_edges);
result.Add(right_edges);
result.Add(top_edges);
result.Add(bottom_edges);
}
else perim = null;
}
// shrink the perimeter according to the erosion/dilation value
if ((perim != null) && (erode_dilate != 0))
{
if (perim.x_points != null)
{
float shrink_percent = (erode_dilate*2) / (perim.getPerimeterLength()/4.0f);
perim = perim.Scale(1.0f - shrink_percent);
}
else perim = null;
}
return(result);
}
public static List<List<int>> GetGroups(List<int>edges,
int img_width, int img_height,
int image_border,
int minimum_size_percent,
bool squares_only,
int max_search_depth,
bool ignore_periphery,
int grouping_radius_percent)
{
#if SHOW_TIMINGS
stopwatch timer_grouping = new stopwatch();
timer_grouping.Start();
#endif
const int compression = 4;
int grouping_radius = grouping_radius_percent * img_width / (100 * compression);
List<List<int>> groups = new List<List<int>>();
// find line segments of significant length
List<float> centres = null;
List<float> bounding_boxes = null;
List<List<int>> line_segments =
DetectLongestPerimeters(edges,
img_width, img_height,
image_border,
minimum_size_percent,
squares_only,
max_search_depth,
ignore_periphery,
ref centres,
ref bounding_boxes);
bool[][] grouping_matrix = new bool[line_segments.Count][];
for (int i = 0; i < line_segments.Count; i++)
grouping_matrix[i] = new bool[line_segments.Count];
// map out the line segments
const int step_size = 4;
int ty = img_height-1;
int by = 0;
int tx = img_width-1;
int bx = 0;
int[,] line_segment_map = new int[(img_width/compression)+2, (img_height/compression)+2];
for (int i = 0; i < line_segments.Count; i++)
{
List<int> line_segment = line_segments[i];
for (int j = 0; j < line_segment.Count; j += step_size)
{
int x = line_segment[j]/compression;
int y = line_segment[j+1]/compression;
if (line_segment_map[x, y] > 0)
{
if (line_segment_map[x, y] != i + 1)
{
int segment_index1 = line_segment_map[x, y]-1;
int segment_index2 = i;
// link the two segments
grouping_matrix[segment_index1][segment_index2] = true;
grouping_matrix[segment_index2][segment_index1] = true;
}
}
line_segment_map[x, y] = i + 1;
if (x < tx) tx = x;
if (x > bx) bx = x;
if (y < ty) ty = y;
if (y > by) by = y;
}
}
// horizontal grouping
for (int y = ty; y <= by; y++)
{
int prev_segment_index = -1;
int prev_segment_x = -1;
for (int x = tx; x <= bx; x++)
{
int segment_index = line_segment_map[x, y];
if (segment_index > 0)
{
if (prev_segment_x > -1)
{
int dx = x - prev_segment_x;
if (dx < grouping_radius)
{
if (!grouping_matrix[segment_index-1][prev_segment_index])
{
// get the line segment indexes
segment_index--;
if (segment_index != prev_segment_index)
{
// link the two segments
grouping_matrix[segment_index][prev_segment_index] = true;
grouping_matrix[prev_segment_index][segment_index] = true;
}
}
}
}
prev_segment_x = x;
prev_segment_index = line_segment_map[x, y]-1;
}
}
}
// horizontal grouping
for (int x = tx; x <= bx; x++)
{
int prev_segment_y = -1;
int prev_segment_index = -1;
for (int y = ty; y <= by; y++)
{
int segment_index = line_segment_map[x, y];
if (segment_index > 0)
{
if (prev_segment_y > -1)
{
int dy = y - prev_segment_y;
if (dy < grouping_radius)
{
if (!grouping_matrix[segment_index-1][prev_segment_index])
{
// get the line segment indexes
segment_index--;
if (segment_index != prev_segment_index)
{
// link the two segments
grouping_matrix[segment_index][prev_segment_index] = true;
grouping_matrix[prev_segment_index][segment_index] = true;
}
}
}
}
prev_segment_y = y;
prev_segment_index = line_segment_map[x, y]-1;
}
}
}
// turn grouping matrix into a hypergraph
hypergraph graph = new hypergraph(grouping_matrix.Length, 1);
for (int i = 0; i < grouping_matrix.Length; i++)
{
for (int j = 0; j < grouping_matrix[i].Length; j++)
{
if (grouping_matrix[i][j])
graph.LinkByIndex(j, i);
}
}
// detect connected sets within the hypergraph
for (int i = 0; i < graph.Nodes.Count; i++)
{
bool already_grouped = graph.GetFlagByIndex(i, 0);
if (!already_grouped)
{
List<hypergraph_node> connected_set = new List<hypergraph_node>();
graph.PropogateFlagFromIndex(i, 0, connected_set);
List<hypergraph_node> members = new List<hypergraph_node>();
for (int j = 0; j < connected_set.Count; j++)
{
if (!members.Contains(connected_set[j])) members.Add(connected_set[j]);
}
List<int> group_members = new List<int>();
for (int j = 0; j < members.Count; j++)
{
int line_segment_index = members[j].ID;
List<int> perim = line_segments[line_segment_index];
for (int k = 0; k < perim.Count; k++)
group_members.Add(perim[k]);
}
groups.Add(group_members);
}
}
#if SHOW_TIMINGS
timer_grouping.Stop();
//if (timer_grouping.time_elapsed_mS > 20)
Console.WriteLine("GetGroups: " + timer_grouping.time_elapsed_mS.ToString() );
#endif
return(groups);
}