/// <returns> true iff we have found at least 3 finder patterns that have been detected
/// at least {@link #CENTER_QUORUM} times each, and, the estimated module size of the
/// candidates is "pretty similar"
/// </returns>
private bool haveMultiplyConfirmedCenters()
{
int confirmedCount = 0;
float totalModuleSize = 0.0f;
int max = possibleCenters.Count;
for (int i = 0; i < max; i++)
{
FinderPattern pattern = (FinderPattern)possibleCenters[i];
if (pattern.Count >= CENTER_QUORUM)
{
confirmedCount++;
totalModuleSize += pattern.EstimatedModuleSize;
}
}
if (confirmedCount < 3)
{
return(false);
}
// OK, we have at least 3 confirmed centers, but, it's possible that one is a "false positive"
// and that we need to keep looking. We detect this by asking if the estimated module sizes
// vary too much. We arbitrarily say that when the total deviation from average exceeds
// 5% of the total module size estimates, it's too much.
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
float average = totalModuleSize / (float)max;
float totalDeviation = 0.0f;
for (int i = 0; i < max; i++)
{
FinderPattern pattern = (FinderPattern)possibleCenters[i];
totalDeviation += System.Math.Abs(pattern.EstimatedModuleSize - average);
}
return(totalDeviation <= 0.05f * totalModuleSize);
}
/// <returns> number of rows we could safely skip during scanning, based on the first
/// two finder patterns that have been located. In some cases their position will
/// allow us to infer that the third pattern must lie below a certain point farther
/// down in the image.
/// </returns>
private int findRowSkip()
{
int max = possibleCenters.Count;
if (max <= 1)
{
return(0);
}
FinderPattern firstConfirmedCenter = null;
for (int i = 0; i < max; i++)
{
FinderPattern center = (FinderPattern)possibleCenters[i];
if (center.Count >= CENTER_QUORUM)
{
if (firstConfirmedCenter == null)
{
firstConfirmedCenter = center;
}
else
{
// We have two confirmed centers
// How far down can we skip before resuming looking for the next
// pattern? In the worst case, only the difference between the
// difference in the x / y coordinates of the two centers.
// This is the case where you find top left last.
hasSkipped = true;
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
return((int)(System.Math.Abs(firstConfirmedCenter.X - center.X) - System.Math.Abs(firstConfirmedCenter.Y - center.Y)) / 2);
}
}
}
return(0);
}
/// <summary> <p>This is called when a horizontal scan finds a possible alignment pattern. It will
/// cross check with a vertical scan, and if successful, will, ah, cross-cross-check
/// with another horizontal scan. This is needed primarily to locate the real horizontal
/// center of the pattern in cases of extreme skew.</p>
///
/// <p>If that succeeds the finder pattern location is added to a list that tracks
/// the number of times each location has been nearly-matched as a finder pattern.
/// Each additional find is more evidence that the location is in fact a finder
/// pattern center
///
/// </summary>
/// <param name="stateCount">reading state module counts from horizontal scan
/// </param>
/// <param name="i">row where finder pattern may be found
/// </param>
/// <param name="j">end of possible finder pattern in row
/// </param>
/// <returns> true if a finder pattern candidate was found this time
/// </returns>
protected internal virtual bool handlePossibleCenter(int[] stateCount, int i, int j)
{
int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] + stateCount[4];
float centerJ = centerFromEnd(stateCount, j);
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
float centerI = crossCheckVertical(i, (int)centerJ, stateCount[2], stateCountTotal);
if (!System.Single.IsNaN(centerI))
{
// Re-cross check
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
centerJ = crossCheckHorizontal((int)centerJ, (int)centerI, stateCount[2], stateCountTotal);
if (!System.Single.IsNaN(centerJ))
{
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
float estimatedModuleSize = (float)stateCountTotal / 7.0f;
bool found = false;
int max = possibleCenters.Count;
for (int index = 0; index < max; index++)
{
FinderPattern center = (FinderPattern)possibleCenters[index];
// Look for about the same center and module size:
if (center.aboutEquals(estimatedModuleSize, centerI, centerJ))
{
center.incrementCount();
found = true;
break;
}
}
if (!found)
{
ResultPoint point = new FinderPattern(centerJ, centerI, estimatedModuleSize);
possibleCenters.Add(point);
if (resultPointCallback != null)
{
resultPointCallback.foundPossibleResultPoint(point);
}
}
return(true);
}
}
return(false);
}
/// <returns> the 3 best {@link FinderPattern}s from our list of candidates. The "best" are
/// those that have been detected at least {@link #CENTER_QUORUM} times, and whose module
/// size differs from the average among those patterns the least
/// </returns>
/// <throws> ReaderException if 3 such finder patterns do not exist </throws>
private FinderPattern[] selectBestPatterns()
{
int startSize = possibleCenters.Count;
if (startSize < 3)
{
// Couldn't find enough finder patterns
throw ReaderException.Instance;
}
// Filter outlier possibilities whose module size is too different
if (startSize > 3)
{
// But we can only afford to do so if we have at least 4 possibilities to choose from
float totalModuleSize = 0.0f;
for (int i = 0; i < startSize; i++)
{
totalModuleSize += ((FinderPattern)possibleCenters[i]).EstimatedModuleSize;
}
//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
float average = totalModuleSize / (float)startSize;
for (int i = 0; i < possibleCenters.Count && possibleCenters.Count > 3; i++)
{
FinderPattern pattern = (FinderPattern)possibleCenters[i];
if (System.Math.Abs(pattern.EstimatedModuleSize - average) > 0.2f * average)
{
possibleCenters.RemoveAt(i);
i--;
}
}
}
if (possibleCenters.Count > 3)
{
// Throw away all but those first size candidate points we found.
Collections.insertionSort(possibleCenters, new CenterComparator());
SupportClass.SetCapacity(possibleCenters, 3);
}
return(new FinderPattern[] { (FinderPattern)possibleCenters[0], (FinderPattern)possibleCenters[1], (FinderPattern)possibleCenters[2] });
}
protected internal virtual DetectorResult processFinderPatternInfo(FinderPatternInfo info)
{
FinderPattern topLeft = info.TopLeft;
FinderPattern topRight = info.TopRight;
FinderPattern bottomLeft = info.BottomLeft;
float moduleSize = calculateModuleSize(topLeft, topRight, bottomLeft);
if (moduleSize < 1.0f)
{
throw ReaderException.Instance;
}
int dimension = computeDimension(topLeft, topRight, bottomLeft, moduleSize);
Version provisionalVersion = Version.getProvisionalVersionForDimension(dimension);
int modulesBetweenFPCenters = provisionalVersion.DimensionForVersion - 7;
PerspectiveTransform transform = createTransform(topLeft, topRight, bottomLeft, dimension);
BitMatrix bits = sampleGrid(image, transform, dimension);
ResultPoint[] points;
points = new ResultPoint[] { bottomLeft, topLeft, topRight };
return(new DetectorResult(bits, points));
}
public FinderPatternInfo(FinderPattern[] patternCenters)
{
this.bottomLeft = patternCenters[0];
this.topLeft = patternCenters[1];
this.topRight = patternCenters[2];
}
