public FitLine()
{
CvSize imageSize = new CvSize(500, 500);
// cvFitLine
CvPoint2D32f[] points = GetRandomPoints(20, imageSize);
CvLine2D line = Cv.FitLine2D(points, DistanceType.L2, 0, 0.01, 0.01);
using (IplImage img = new IplImage(imageSize, BitDepth.U8, 3))
{
img.Zero();
// draw line
{
CvPoint pt1, pt2;
line.FitSize(img.Width, img.Height, out pt1, out pt2);
img.Line(pt1, pt2, CvColor.Green, 1, LineType.Link8);
}
// draw points and distances
using (CvFont font = new CvFont(FontFace.HersheySimplex, 0.33, 0.33))
{
foreach (CvPoint2D32f p in points)
{
double d = line.Distance(p);
img.Circle(p, 2, CvColor.White, -1, LineType.AntiAlias);
img.PutText(string.Format("{0:F1}", d), new CvPoint((int)(p.X + 3), (int)(p.Y + 3)), font, CvColor.Green);
}
}
CvWindow.ShowImages(img);
}
}
private void extendLines(CvLineSegmentPoint[] lines, double ext)
{
// TODO : this is stupid way to extend a line, does 2 sqrts and is generally non-comprehensible
// Better just make it parametric, like x = x0 + t * x1, y = y0 + t * y1 where for t=0, {x,y} = P1 & for t=1, {x,y} = P2
// so we can increase in size by percent, like t = +-0.5 (+50%)
//Transfer 2-point line segments to type "a*x=b" CvLine2D format
//TODO : this should probably be redone manually without OpenCV's ultra-generic slow function. We only have 2 points after all.
List <CvLine2D> fitLinesV = new List <CvLine2D>(lines.Length);
CvPoint[] forFitline = new CvPoint[2];
for (int i = 0; i < lines.Length; ++i)
{
forFitline[0] = lines[i].P1;
forFitline[1] = lines[i].P2;
CvLine2D fitLinef = Cv.FitLine2D(forFitline, DistanceType.L2, 0, 0.01, 0.01);
fitLinesV.Add(fitLinef);
}
CvPoint p1, p2, p3, p4;
for (int i = 0; i < lines.Length; i++)
{
CvLineSegmentPoint lineSegm = lines[i];
CvLine2D fitLine = fitLinesV[i];
int fitLineVx = (int)(fitLine.Vx * ext);
int fitLineVy = (int)(fitLine.Vy * ext);
p1 = new CvPoint(lineSegm.P1.X + fitLineVx, lineSegm.P1.Y + fitLineVy);
p2 = new CvPoint(lineSegm.P2.X - fitLineVx, lineSegm.P2.Y - fitLineVy);
p3 = new CvPoint(lineSegm.P1.X - fitLineVx, lineSegm.P1.Y - fitLineVy);
p4 = new CvPoint(lineSegm.P2.X + fitLineVx, lineSegm.P2.Y + fitLineVy);
if (p1.DistanceTo(p2) > p3.DistanceTo(p4))
{
lineSegm.P1.X = p1.X;
lineSegm.P1.Y = p1.Y;
lineSegm.P2.X = p2.X;
lineSegm.P2.Y = p2.Y;
}
else
{
lineSegm.P1.X = p3.X;
lineSegm.P1.Y = p3.Y;
lineSegm.P2.X = p4.X;
lineSegm.P2.Y = p4.Y;
}
}
}
