/// <summary>
/// use canny algorithm to find edges
/// </summary>
/// <param name="bmp"></param>
/// <param name="edge_detector"></param>
/// <param name="dots"></param>
/// <param name="edges_bmp"></param>
private static void DetectEdges(
Bitmap bmp,
ref EdgeDetectorCanny edge_detector,
ref hypergraph dots,
ref Bitmap edges_bmp)
{
byte[] image_data = new byte[bmp.Width * bmp.Height * 3];
BitmapArrayConversions.updatebitmap(bmp, image_data);
if (edge_detector == null) edge_detector = new EdgeDetectorCanny();
edge_detector.automatic_thresholds = true;
edge_detector.connected_sets_only = true;
byte[] edges_data = edge_detector.Update(image_data, bmp.Width, bmp.Height);
bool connected_sets_ok = false;
try
{
edges_data = edge_detector.GetConnectedSetsImage(image_data, 10, bmp.Width / SurveyorCalibration.dots_across * 3, true, ref dots);
connected_sets_ok = true;
}
catch
{
}
if (connected_sets_ok)
{
// locate the red centre dot
int max_redness = 0;
CalibrationDot centre_dot = null;
for (int i = 0; i < dots.Nodes.Count; i++)
{
CalibrationDot dot = (CalibrationDot)dots.Nodes[i];
int n = (((int)dot.y * bmp.Width) + (int)dot.x) * 3;
if ((n > 3) && (n < image_data.Length - 4))
{
int r = image_data[n + 2] + image_data[n + 2 + 3] + image_data[n + 2 - 3];
int g = image_data[n + 1] + image_data[n + 1 + 3] + image_data[n + 1 - 3];
int b = image_data[n] + image_data[n + 3] + image_data[n - 3];
int redness = (r * 2) - g - b;
if (redness > max_redness)
{
max_redness = redness;
centre_dot = dot;
}
}
}
if (centre_dot != null) centre_dot.centre = true;
if (edges_bmp == null)
edges_bmp = new Bitmap(bmp.Width, bmp.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
BitmapArrayConversions.updatebitmap_unsafe(edges_data, edges_bmp);
}
}
protected Bitmap DetectEdges(Bitmap bmp, EdgeDetectorCanny edge_detector,
ref hypergraph dots)
{
usage.Update("Detect edges, BaseVisionStereo, DetectEdges");
byte[] image_data = new byte[bmp.Width * bmp.Height * 3];
BitmapArrayConversions.updatebitmap(bmp, image_data);
if (edge_detector == null) edge_detector = new EdgeDetectorCanny();
edge_detector.automatic_thresholds = true;
edge_detector.connected_sets_only = true;
byte[] edges_data = edge_detector.Update(image_data, bmp.Width, bmp.Height);
edges_data = edge_detector.GetConnectedSetsImage(image_data, 10, bmp.Width / SurveyorCalibration.dots_across * 3, true, ref dots);
Bitmap edges_bmp = new Bitmap(bmp.Width, bmp.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
BitmapArrayConversions.updatebitmap_unsafe(edges_data, edges_bmp);
return(edges_bmp);
}
public static hypergraph DetectDots(
Bitmap bmp,
ref EdgeDetectorCanny edge_detector,
CalibrationSurvey survey,
ref Bitmap detected_dots,
ref Bitmap linked_dots,
ref Bitmap grd,
ref Bitmap grid_diff,
ref Bitmap rectified)
{
const int minimum_links = (dots_across * (dots_across/2)) / 2;
hypergraph dots = null;
DetectEdges(bmp, ref edge_detector, ref dots, ref detected_dots);
if (dots != null)
{
// find the dots around the red centre dot
List<CalibrationDot> centre_dots = null;
polygon2D centre_square = GetCentreSquare(dots, ref centre_dots);
if (centre_square != null)
{
if (centre_square.x_points.Count == 4)
{
// find the orientation of the centre square
float angle = geometry.threePointAngle(
(float)centre_dots[1].x, 0,
(float)centre_dots[1].x, (float)centre_dots[1].y,
(float)centre_dots[2].x, (float)centre_dots[2].y);
angle = angle / (float)Math.PI * 180;
if (angle > 160)
{
angle = geometry.threePointAngle(
(float)centre_dots[2].x, 0,
(float)centre_dots[2].x, (float)centre_dots[2].y,
(float)centre_dots[3].x, (float)centre_dots[3].y);
angle = angle / (float)Math.PI * 180;
if ((angle >= 70) && (angle < 120))
{
// link dots together
List<CalibrationDot> search_regions = new List<CalibrationDot>();
double horizontal_dx = centre_dots[1].x - centre_dots[0].x;
double horizontal_dy = centre_dots[1].y - centre_dots[0].y;
double vertical_dx = centre_dots[3].x - centre_dots[0].x;
double vertical_dy = centre_dots[3].y - centre_dots[0].y;
for (int i = 0; i < centre_dots.Count; i++)
LinkDots(dots, centre_dots[i], horizontal_dx, horizontal_dy, vertical_dx, vertical_dy, 0, search_regions);
if (dots.Links.Count > minimum_links)
{
int tollerance_degrees = 10;
if (ValidGrid(dots, bmp.Width, bmp.Height, tollerance_degrees))
{
ShowLinkedDots(bmp, dots, search_regions, ref linked_dots);
// assign a grid coordinate to each dot
ApplyGrid(dots, centre_dots);
// put the dots into a 2D grid for convenient lookup
CalibrationDot[,] grid = CreateGrid(dots);
if (grid != null)
{
grid2D ideal_grid = GetIdealGrid(grid, bmp.Width, bmp.Height);
ShowIdealGrid(bmp, ideal_grid, grid, ref grd);
ShowIdealGridDiff(bmp, grid, ref grid_diff);
survey.Update(bmp.Width, bmp.Height, grid);
ShowRectifiedImage(bmp, survey.centre_of_distortion_x, survey.centre_of_distortion_y, survey.best_fit_curve, ref rectified);
}
}
}
}
}
}
}
}
return(dots);
}
