///''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
//use Pythagorean theorem to calculate distance between two chars
public double distanceBetweenChars(PossibleChar firstChar, PossibleChar secondChar)
{
int intX = Math.Abs(firstChar.intCenterX - secondChar.intCenterX);
int intY = Math.Abs(firstChar.intCenterY - secondChar.intCenterY);
return(Math.Sqrt((Math.Pow(intX, 2)) + (Math.Pow(intY, 2))));
}
///''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
public List <PossibleChar> findPossibleCharsInPlate(Mat imgGrayscale, Mat imgThresh)
{
List <PossibleChar> listOfPossibleChars = new List <PossibleChar>();
//this will be the return value
Mat imgThreshCopy = new Mat();
VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint();
imgThreshCopy = imgThresh.Clone();
CvInvoke.FindContours(imgThreshCopy, contours, null, RetrType.List, ChainApproxMethod.ChainApproxSimple);
//find all contours in plate
//for each contour
for (int i = 0; i <= contours.Size - 1; i++)
{
PossibleChar possibleChar = new PossibleChar(contours[i]);
//if contour is a possible char, note this does not compare to other chars (yet) . . .
if ((checkIfPossibleChar(possibleChar)))
{
listOfPossibleChars.Add(possibleChar);
//add to list of possible chars
}
}
return(listOfPossibleChars);
}
///''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
//use basic trigonometry (SOH CAH TOA) to calculate angle between chars
public double angleBetweenChars(PossibleChar firstChar, PossibleChar secondChar)
{
double dblAdj = Convert.ToDouble(Math.Abs(firstChar.intCenterX - secondChar.intCenterX));
double dblOpp = Convert.ToDouble(Math.Abs(firstChar.intCenterY - secondChar.intCenterY));
double dblAngleInRad = Math.Atan(dblOpp / dblAdj);
double dblAngleInDeg = dblAngleInRad * (180.0 / Math.PI);
return(dblAngleInDeg);
}
///''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
public bool checkIfPossibleChar(PossibleChar possibleChar)
{
//this function is a 'first pass' that does a rough check on a contour to see if it could be a char,
//note that we are not (yet) comparing the char to other chars to look for a group
if ((possibleChar.intRectArea > MIN_RECT_AREA & possibleChar.boundingRect.Width > MIN_PIXEL_WIDTH & possibleChar.boundingRect.Height > MIN_PIXEL_HEIGHT & MIN_ASPECT_RATIO < possibleChar.dblAspectRatio & possibleChar.dblAspectRatio < MAX_ASPECT_RATIO))
{
return(true);
}
else
{
return(false);
}
}
///''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
public List <PossibleChar> findPossibleCharsInScene(Mat imgThresh)
{
List <PossibleChar> listOfPossibleChars = new List <PossibleChar>();
//this is the return value
Mat imgContours = new Mat(imgThresh.Size, DepthType.Cv8U, 3);
int intCountOfPossibleChars = 0;
Mat imgThreshCopy = imgThresh.Clone();
VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint();
CvInvoke.FindContours(imgThreshCopy, contours, null, RetrType.List, ChainApproxMethod.ChainApproxSimple);
//find all contours
//for each contour
for (int i = 0; i <= contours.Size - 1; i++)
{
// show steps '''''''''''''''''''''''''''''
if ((frm.cbShowSteps.Checked == true))
{
CvInvoke.DrawContours(imgContours, contours, i, SCALAR_WHITE);
}
// show steps '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
PossibleChar possibleChar = new PossibleChar(contours[i]);
//if contour is a possible char, note this does not compare to other chars (yet) . . .
if ((detectChars.checkIfPossibleChar(possibleChar)))
{
intCountOfPossibleChars = intCountOfPossibleChars + 1;
//increment count of possible chars
listOfPossibleChars.Add(possibleChar);
//and add to list of possible chars
}
}
// show steps '''''''''''''''''''''''''''''''''
if ((frm.cbShowSteps.Checked == true))
{
frm.txtInfo.AppendText("\r\n" + "step 2 - contours.Size() = " + contours.Size.ToString() + "\r\n");
//2362 with MCLRNF1 image
frm.txtInfo.AppendText("step 2 - intCountOfPossibleChars = " + intCountOfPossibleChars.ToString() + "\r\n");
//131 with MCLRNF1 image
CvInvoke.Imshow("2a", imgContours);
}
// show steps '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
return(listOfPossibleChars);
}
///''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
public List <PossibleChar> findListOfMatchingChars(PossibleChar possibleChar, List <PossibleChar> listOfChars)
{
//the purpose of this function is, given a possible char and a big list of possible chars,
//find all chars in the big list that are a match for the single possible char, and return those matching chars as a list
List <PossibleChar> listOfMatchingChars = new List <PossibleChar>();
//this will be the return value
//for each char in big list
foreach (PossibleChar possibleMatchingChar in listOfChars)
{
//if the char we attempting to find matches for is the exact same char as the char in the big list we are currently checking
if ((possibleMatchingChar.Equals(possibleChar)))
{
//then we should not include it in the list of matches b/c that would end up double including the current char
continue;
//so do not add to list of matches and jump back to top of for loop
}
//compute stuff to see if chars are a match
double dblDistanceBetweenChars = distanceBetweenChars(possibleChar, possibleMatchingChar);
double dblAngleBetweenChars = angleBetweenChars(possibleChar, possibleMatchingChar);
double dblChangeInArea = Math.Abs(possibleMatchingChar.intRectArea - possibleChar.intRectArea) / possibleChar.intRectArea;
double dblChangeInWidth = Math.Abs(possibleMatchingChar.boundingRect.Width - possibleChar.boundingRect.Width) / possibleChar.boundingRect.Width;
double dblChangeInHeight = Math.Abs(possibleMatchingChar.boundingRect.Height - possibleChar.boundingRect.Height) / possibleChar.boundingRect.Height;
//check if chars match
if ((dblDistanceBetweenChars < (possibleChar.dblDiagonalSize * MAX_DIAG_SIZE_MULTIPLE_AWAY)
& dblAngleBetweenChars < MAX_ANGLE_BETWEEN_CHARS
& dblChangeInArea < MAX_CHANGE_IN_AREA
& dblChangeInWidth < MAX_CHANGE_IN_WIDTH
& dblChangeInHeight < MAX_CHANGE_IN_HEIGHT))
{
listOfMatchingChars.Add(possibleMatchingChar);
//if the chars are a match, add the current char to list of matching chars
}
}
return(listOfMatchingChars);
//return result
}
