/// <summary>
/// Generates a binary image where only the lane markings wil be high.
/// Filters based on color (allows white & yellow markings).
/// </summary>
/// <param name="src"> BGR image to filter </param>
/// <returns> Binary lane markings image </returns>
public Mat FilterMarkings(Mat src)
{
// Filter (pass) white & yellow
Mat white = FilterHSV(src, HsvWhiteMin, HsvWhiteMax);
Mat yellow = FilterHSV(src, HsvYellowMin, HsvYellowMax);
// Equalize histogram and thresh
Mat whiteFromEq = GetWhiteFromHistogramEq(src, 250, 255);
Mat bin = new Mat(src.Rows(), src.Cols(), CvType.Cv8uc1, Scalar.All(0));
Core.Core.Bitwise_or(bin, white, bin);
Core.Core.Bitwise_or(bin, yellow, bin);
Core.Core.Bitwise_or(bin, whiteFromEq, bin);
//kernel.SetTo(new Scalar(1));
Imgproc.MorphologyEx(bin, bin, Imgproc.MorphClose, kernel, new Point(-1, -1), 1);
white.Release();
yellow.Release();
whiteFromEq.Release();
return(bin);
}
private IList <MatOfPoint> ProcessImage()
{
Mat grayMat = new Mat();
Mat blurMat = new Mat();
Mat edgesMat = new Mat();
Mat final = new Mat();
Mat h = new Mat();
IList <MatOfPoint> contours = new JavaList <MatOfPoint>();
OpenCV.Android.Utils.BitmapToMat(originalImage, originalMat);
originalImage.Dispose();
Imgproc.CvtColor(originalMat, grayMat, Imgproc.ColorBgr2gray);
Imgproc.GaussianBlur(grayMat, blurMat, new OpenCV.Core.Size(3, 3), 0);
Imgproc.Canny(blurMat, edgesMat, 10, 250);
Mat kernel = Imgproc.GetStructuringElement(Imgproc.MorphRect, new Size(3, 3));
Imgproc.MorphologyEx(edgesMat, final, Imgproc.MorphClose, kernel);
Imgproc.FindContours(final, contours, h, Imgproc.RetrExternal, Imgproc.ChainApproxSimple);
return(contours);
}
public static async Task <string> detectAndExtractText(Bitmap img)
{
//Matrix für die Bilder
Mat large = new Mat();
Mat small = new Mat();
Mat rgb = new Mat();
//Bild zu Matrix umwandeln
Utils.BitmapToMat(img, large);
// downsample and use it for processing
Imgproc.PyrDown(large, rgb);
//Grey
Imgproc.CvtColor(rgb, small, Imgproc.ColorBgr2gray);
//Gradiant
Mat grad = new Mat();
Size morphsize = new Size(3.0, 3.0);
Mat morphKernel = Imgproc.GetStructuringElement(Imgproc.MorphEllipse, morphsize);
Imgproc.MorphologyEx(small, grad, Imgproc.MorphGradient, morphKernel);
//Binarize
Mat bw = new Mat();
Imgproc.Threshold(grad, bw, 0.0, 255.0, Imgproc.ThreshBinary | Imgproc.ThreshOtsu);
// connect horizontally oriented regions
Mat connected = new Mat();
Size connectsize = new Size(9.0, 1.0);
morphKernel = Imgproc.GetStructuringElement(Imgproc.MorphRect, connectsize);
Imgproc.MorphologyEx(bw, connected, Imgproc.MorphClose, morphKernel);
// find contours
Mat mask = Mat.Zeros(bw.Size(), CvType.Cv8uc1);
JavaList <MatOfPoint> contours = new JavaList <MatOfPoint>();
Mat hierarchy = new Mat();
OpenCV.Core.Point contourPoint = new OpenCV.Core.Point(0, 0);
Imgproc.FindContours(connected, contours, hierarchy, Imgproc.RetrCcomp, Imgproc.ChainApproxSimple, contourPoint);
Scalar zero = new Scalar(0, 0, 0);
Scalar contourscal = new Scalar(255, 255, 255);
Scalar rectScalar = new Scalar(0, 255, 0);
OpenCV.Core.Rect rect;
Mat maskROI;
double r;
double[] contourInfo;
string resulttext = "";
string part;
Bitmap bmpOcr;
Mat croppedPart;
for (int i = 0; i >= 0;)
{
rect = Imgproc.BoundingRect(contours[i]);
maskROI = new Mat(mask, rect);
maskROI.SetTo(zero);
//fill the contour
Imgproc.DrawContours(mask, contours, i, contourscal, Core.Filled);
// ratio of non-zero pixels in the filled region
r = (double)Core.CountNonZero(maskROI) / (rect.Width * rect.Height);
/* assume at least 45% of the area is filled if it contains text */
/* constraints on region size */
/* these two conditions alone are not very robust. better to use something
* like the number of significant peaks in a horizontal projection as a third condition */
if (r > .45 && (rect.Height > 8 && rect.Width > 8))
{
//Imgproc.Rectangle(rgb, rect.Br(), rect.Tl(), rectScalar, 2);
try
{
croppedPart = rgb.Submat(rect);
bmpOcr = Bitmap.CreateBitmap(croppedPart.Width(), croppedPart.Height(), Bitmap.Config.Argb8888);
Utils.MatToBitmap(croppedPart, bmpOcr);
part = await OCR.getText(bmpOcr);
resulttext = resulttext + part;
Console.WriteLine("------------------Durchlauf-------------");
}
catch (Exception e)
{
Android.Util.Log.Debug("Fehler", "cropped part data error " + e.Message);
}
}
//Nächste Element bestimmen
contourInfo = hierarchy.Get(0, i);
i = (int)contourInfo[0];
}
return(resulttext);
}
