/// <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);
}
public static void ShowPeriphery(string filename,
string periphery_filename,
int grouping_radius_percent,
int erosion_dilation,
int minimum_size_percent,
bool black_on_white,
bool squares_only)
{
const int max_search_depth = 8000;
const int connect_edges_radius = 5;
if (File.Exists(filename))
{
Bitmap bmp = (Bitmap)Bitmap.FromFile(filename);
byte[] img = new byte[bmp.Width * bmp.Height * 3];
byte[] squares_img = null; //new byte[bmp.Width * bmp.Height * 3];
BitmapArrayConversions.updatebitmap(bmp, img);
// convert to mono
byte[] img_mono = image.monoImage(img, bmp.Width, bmp.Height);
if (!black_on_white)
{
for (int i = 0; i < img_mono.Length; i++)
img_mono[i] = (byte)(255 - img_mono[i]);
}
if (erosion_dilation > 0)
{
byte[] eroded = image.Erode(img_mono, bmp.Width, bmp.Height, erosion_dilation, null);
img_mono = eroded;
}
if (erosion_dilation < 0)
{
byte[] dilated = image.Dilate(img_mono, bmp.Width, bmp.Height, -erosion_dilation, null);
img_mono = dilated;
}
CannyEdgeDetector edge_detector = new CannyEdgeDetector();
edge_detector.automatic_thresholds = true;
edge_detector.Update(img_mono, bmp.Width, bmp.Height);
edge_detector.ConnectBrokenEdges(connect_edges_radius);
// group edges together into objects
List<List<int>> groups =
GetGroups(edge_detector.edges,
bmp.Width, bmp.Height, 0,
minimum_size_percent,
false, max_search_depth, false,
grouping_radius_percent);
if (groups != null)
{
float minimum_aspect_ratio = 0.7f;
float maximum_aspect_ratio = 1.3f;
if (!squares_only)
{
minimum_aspect_ratio = 0.3f;
maximum_aspect_ratio = 20.0f;
}
// get the set of edges with aspect ratio closest to square
List<List<int>> squares = GetAspectRange(groups,
bmp.Width, bmp.Height,
minimum_aspect_ratio, maximum_aspect_ratio,
minimum_size_percent, squares_only);
if (squares != null)
{
for (int i = 0; i < squares.Count; i++)
{
List<int> square = squares[i];
polygon2D perim = null;
List<List<int>> periphery = GetSquarePeriphery(square, erosion_dilation, ref perim);
if (perim != null)
{
squares_img = ShowEdges(ref squares_img, periphery, bmp.Width, bmp.Height);
if (squares_img != null)
perim.show(squares_img, bmp.Width, bmp.Height, 150, 150, 150, 0);
}
}
}
}
Bitmap periphery_bmp = new Bitmap(bmp.Width, bmp.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
BitmapArrayConversions.updatebitmap_unsafe(squares_img, periphery_bmp);
periphery_bmp.Save(periphery_filename, System.Drawing.Imaging.ImageFormat.Bmp);
}
}
public static void ShowRectangles(string filename,
string square_filename,
bool ignore_periphery,
int image_border_percent,
int grouping_radius_percent,
int minimum_size_percent,
bool show_centres,
int erosion_dilation,
bool black_on_white,
int minimum_volume_percent)
{
const int max_search_depth = 8000;
const int connect_edges_radius = 5;
if (File.Exists(filename))
{
Bitmap bmp = (Bitmap)Bitmap.FromFile(filename);
byte[] img = new byte[bmp.Width * bmp.Height * 3];
BitmapArrayConversions.updatebitmap(bmp, img);
if (!black_on_white)
{
for (int i = 0; i < img.Length; i++)
{
img[i] = (byte)(255 - img[i]);
}
}
int image_border = bmp.Width * image_border_percent / 100;
// convert to mono
byte[] img_mono = image.monoImage(img, bmp.Width, bmp.Height);
if (erosion_dilation > 0)
{
byte[] eroded = image.Erode(img_mono, bmp.Width, bmp.Height, erosion_dilation, null);
img_mono = eroded;
}
if (erosion_dilation < 0)
{
byte[] dilated = image.Dilate(img_mono, bmp.Width, bmp.Height, -erosion_dilation, null);
img_mono = dilated;
}
CannyEdgeDetector edge_detector = new CannyEdgeDetector();
edge_detector.automatic_thresholds = true;
edge_detector.Update(img_mono, bmp.Width, bmp.Height);
edge_detector.ConnectBrokenEdges(connect_edges_radius);
List<List<int>> groups =
GetGroups(edge_detector.edges,
bmp.Width, bmp.Height, image_border,
minimum_size_percent,
false, max_search_depth, ignore_periphery,
grouping_radius_percent);
if (groups != null)
{
// get the set of edges with aspect ratio closest to square
List<List<int>> squares = GetAspectRange(groups,
bmp.Width, bmp.Height,
0.3f, 20.0f,
minimum_size_percent, false);
//Console.WriteLine("squares: " + squares.Count.ToString());
if (squares != null)
{
byte[] squareImage = null;
squareImage = ShowEdges(ref squareImage, squares, bmp.Width, bmp.Height);
Bitmap square_bmp = new Bitmap(bmp.Width, bmp.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
BitmapArrayConversions.updatebitmap_unsafe(squareImage, square_bmp);
square_bmp.Save(square_filename, System.Drawing.Imaging.ImageFormat.Bmp);
}
}
}
}
public static void ShowPerimeters(string filename,
string edges_filename,
string magnitudes_filename,
string perimeters_filename,
bool ignore_periphery,
int grouping_radius_percent,
int minimum_size_percent,
bool show_centres,
int erosion_dilation,
bool black_on_white)
{
const int max_search_depth = 8000;
const int connect_edges_radius = 5;
if (File.Exists(filename))
{
Bitmap bmp = (Bitmap)Bitmap.FromFile(filename);
byte[] img = new byte[bmp.Width * bmp.Height * 3];
BitmapArrayConversions.updatebitmap(bmp, img);
if (!black_on_white)
{
for (int i = 0; i < img.Length; i++)
{
img[i] = (byte)(255 - img[i]);
}
}
// convert to mono
byte[] img_mono = image.monoImage(img, bmp.Width, bmp.Height);
if (erosion_dilation > 0)
{
byte[] eroded = image.Erode(img_mono, bmp.Width, bmp.Height, erosion_dilation, null);
img_mono = eroded;
}
if (erosion_dilation < 0)
{
byte[] dilated = image.Dilate(img_mono, bmp.Width, bmp.Height, -erosion_dilation, null);
img_mono = dilated;
}
CannyEdgeDetector edge_detector = new CannyEdgeDetector();
edge_detector.automatic_thresholds = true;
edge_detector.Update(img_mono, bmp.Width, bmp.Height);
edge_detector.ConnectBrokenEdges(connect_edges_radius);
byte[] magnitudes = new byte[bmp.Width * bmp.Height * 3];
edge_detector.ShowMagnitudes(magnitudes, bmp.Width, bmp.Height);
Bitmap magnitudes_bmp = new Bitmap(bmp.Width, bmp.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
BitmapArrayConversions.updatebitmap_unsafe(magnitudes, magnitudes_bmp);
magnitudes_bmp.Save(magnitudes_filename, System.Drawing.Imaging.ImageFormat.Bmp);
/*
byte[] perimetersImage =
ShowLongestPerimeters(edge_detector.edges,
bmp.Width, bmp.Height,
0, minimum_size_percent, false,
max_search_depth,
ignore_periphery,
show_centres);
*/
List<List<int>> groups = null;
byte[] perimetersImage = ShowGroups(edge_detector.edges,
bmp.Width, bmp.Height,
0, minimum_size_percent,
false,
max_search_depth,
ignore_periphery,
grouping_radius_percent,
ref groups);
Bitmap edges_bmp = new Bitmap(bmp.Width, bmp.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
BitmapArrayConversions.updatebitmap_unsafe(edge_detector.getEdgesImage(), edges_bmp);
edges_bmp.Save(edges_filename, System.Drawing.Imaging.ImageFormat.Bmp);
Bitmap perimeters_bmp = new Bitmap(bmp.Width, bmp.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
BitmapArrayConversions.updatebitmap_unsafe(perimetersImage, perimeters_bmp);
perimeters_bmp.Save(perimeters_filename, System.Drawing.Imaging.ImageFormat.Bmp);
}
}
public static List<calibrationDot> DetectDots(byte[] mono_img, byte[] img_colour,
int img_width, int img_height,
int grouping_radius_percent,
int erosion_dilation,
float minimum_width,
float maximum_width,
ref List<int> edges,
ref List<List<int>> groups)
{
// create a list to store the results
List<calibrationDot> dots = null;
const int connect_edges_radius = 5;
int minimum_width_pixels = (int)(minimum_width * img_width / 100);
int maximum_width_pixels = (int)(maximum_width * img_width / 100);
int minimum_size_percent = (int)((minimum_width_pixels*minimum_width_pixels) * 100 / (img_width*img_height));
// maximum recursion depth when joining edges
const int max_search_depth = 8000;
// create edge detection object
CannyEdgeDetector edge_detector = new CannyEdgeDetector();
edge_detector.automatic_thresholds = true;
edge_detector.enable_edge_orientations = false;
byte[] img_mono = (byte[])mono_img.Clone();
// erode
if (erosion_dilation > 0)
{
byte[] eroded = image.Erode(img_mono, img_width, img_height,
erosion_dilation,
null);
img_mono = eroded;
}
// dilate
if (erosion_dilation < 0)
{
byte[] dilated = image.Dilate(img_mono, img_width, img_height,
-erosion_dilation,
null);
img_mono = dilated;
}
// detect edges using canny algorithm
edge_detector.Update(img_mono, img_width, img_height);
// connect edges which are a short distance apart
edge_detector.ConnectBrokenEdges(connect_edges_radius);
edges = edge_detector.edges;
// group edges together into objects
groups = GetGroups(edge_detector.edges,
img_width, img_height, 0,
minimum_size_percent,
false, max_search_depth, false,
grouping_radius_percent);
if (groups != null)
{
dots = GetDots(groups, img_colour,
img_width, img_height,
0.7f, 1.3f,
minimum_width_pixels, maximum_width_pixels);
}
// remove any overlapping squares
//dot_shapes = SelectSquares(dot_shapes, 0);
return(dots);
}
