static public void DeskewAsColumnOfBlocks(ref Bitmap bitmap, int blockMaxHeight, int minBlockSpan)
{
using (Image <Rgb, byte> image = bitmap.ToImage <Rgb, byte>())
{
bitmap.Dispose();
//return image.ToBitmap();
Image <Rgb, byte> deskewedimage = new Image <Rgb, byte>(image.Size);
Image <Gray, byte> image2 = image.Convert <Gray, byte>();
CvInvoke.BitwiseNot(image2, image2);
//CvInvoke.Blur(image2, image2, new Size(3, 3), new Point(0, 0));
CvInvoke.GaussianBlur(image2, image2, new Size(25, 25), 5);//remove small spots
CvInvoke.Threshold(image2, image2, 125, 255, ThresholdType.Otsu | ThresholdType.Binary);
Mat se = CvInvoke.GetStructuringElement(ElementShape.Rectangle, new Size(5, 5), new Point(-1, -1));
CvInvoke.Dilate(image2, image2, se, new Point(-1, -1), 1, BorderType.Constant, CvInvoke.MorphologyDefaultBorderValue);
//CvInvoke.Erode(image2, image2, se, new Point(-1, -1), 5, BorderType.Constant, CvInvoke.MorphologyDefaultBorderValue);
//CvInvoke.BitwiseNot(image2, image2);
//return image2.ToBitmap();
VectorOfVectorOfPoint cs = new VectorOfVectorOfPoint();
Mat h = new Mat();
CvInvoke.FindContours(image2, cs, h, RetrType.Tree, ChainApproxMethod.ChainApproxSimple);
if (cs.Size < 1)
{
return;
}
Array hierarchy = h.GetData();
List <Contour> contours = new List <Contour>();
for (int i = 0; i < cs.Size; i++)
{
int p = (int)hierarchy.GetValue(0, i, Contour.HierarchyKey.Parent);
if (p < 1)
{
contours.Add(new Contour(hierarchy, i, cs[i]));
}
}
if (contours.Where(a => a.ParentId < 0).Count() < 2)//the only parent is the whole page frame
{
contours.RemoveAll(a => a.ParentId < 0);
}
else
{
contours.RemoveAll(a => a.ParentId >= 0);
}
contours = contours.OrderBy(a => a.BoundingRectangle.Bottom).ToList();
for (int blockY = 0; blockY < image.Height;)
{
int blockBottom = image.Height - 1;
Tuple <Contour, Contour> lastSpan = null;
for (; contours.Count > 0;)
{
Contour c = contours[0];
contours.RemoveAt(0);
if (contours.Count > 0)
{
Contour minTop = contours.Aggregate((a, b) => a.BoundingRectangle.Top < b.BoundingRectangle.Top ? a : b);
if (c.BoundingRectangle.Bottom + minBlockSpan <= minTop.BoundingRectangle.Top)
{
lastSpan = new Tuple <Contour, Contour>(c, minTop);
}
}
if (c.BoundingRectangle.Bottom > blockY + blockMaxHeight && lastSpan != null)
{
blockBottom = lastSpan.Item1.BoundingRectangle.Bottom + minBlockSpan / 2;
break;
}
}
Rectangle blockRectangle = new Rectangle(0, blockY, image2.Width, blockBottom + 1 - blockY);
Image <Rgb, byte> blockImage = image.Copy(blockRectangle);
blockImage = deskew(blockImage);
deskewedimage.ROI = blockRectangle;
blockImage.CopyTo(deskewedimage);
deskewedimage.ROI = Rectangle.Empty;
// break;
blockY = blockBottom + 1;
}
bitmap = deskewedimage?.ToBitmap();
}
}
public Match(Contour templateContour, Contour pageContour)
{
TemplateContour = templateContour;
PageContour = pageContour;
}