/// <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()
{
System.Collections.ArrayList possibleCenters = PossibleCenters;
int size = possibleCenters.Count;
if (size < 3)
{
// Couldn't find enough finder patterns
throw ReaderException.Instance;
}
/*
* Begin HE modifications to safely detect multiple codes of equal size
*/
if (size == 3)
{
return new FinderPattern[][]{new FinderPattern[]{(FinderPattern) possibleCenters[0], (FinderPattern) possibleCenters[1], (FinderPattern) possibleCenters[2]}};
}
// Sort by estimated module size to speed up the upcoming checks
Collections.insertionSort(possibleCenters, new ModuleSizeComparator());
/*
* Now lets start: build a list of tuples of three finder locations that
* - feature similar module sizes
* - are placed in a distance so the estimated module count is within the QR specification
* - have similar distance between upper left/right and left top/bottom finder patterns
* - form a triangle with 90° angle (checked by comparing top right/bottom left distance
* with pythagoras)
*
* Note: we allow each point to be used for more than one code region: this might seem
* counterintuitive at first, but the performance penalty is not that big. At this point,
* we cannot make a good quality decision whether the three finders actually represent
* a QR code, or are just by chance layouted so it looks like there might be a QR code there.
* So, if the layout seems right, lets have the decoder try to decode.
*/
System.Collections.ArrayList results = System.Collections.ArrayList.Synchronized(new System.Collections.ArrayList(10)); // holder for the results
for (int i1 = 0; i1 < (size - 2); i1++)
{
FinderPattern p1 = (FinderPattern) possibleCenters[i1];
if (p1 == null)
{
continue;
}
for (int i2 = i1 + 1; i2 < (size - 1); i2++)
{
FinderPattern p2 = (FinderPattern) possibleCenters[i2];
if (p2 == null)
{
continue;
}
// Compare the expected module sizes; if they are really off, skip
float vModSize12 = (p1.EstimatedModuleSize - p2.EstimatedModuleSize) / (System.Math.Min(p1.EstimatedModuleSize, p2.EstimatedModuleSize));
float vModSize12A = System.Math.Abs(p1.EstimatedModuleSize - p2.EstimatedModuleSize);
if (vModSize12A > DIFF_MODSIZE_CUTOFF && vModSize12 >= DIFF_MODSIZE_CUTOFF_PERCENT)
{
// break, since elements are ordered by the module size deviation there cannot be
// any more interesting elements for the given p1.
break;
}
for (int i3 = i2 + 1; i3 < size; i3++)
{
FinderPattern p3 = (FinderPattern) possibleCenters[i3];
if (p3 == null)
{
continue;
}
// Compare the expected module sizes; if they are really off, skip
float vModSize23 = (p2.EstimatedModuleSize - p3.EstimatedModuleSize) / (System.Math.Min(p2.EstimatedModuleSize, p3.EstimatedModuleSize));
float vModSize23A = System.Math.Abs(p2.EstimatedModuleSize - p3.EstimatedModuleSize);
if (vModSize23A > DIFF_MODSIZE_CUTOFF && vModSize23 >= DIFF_MODSIZE_CUTOFF_PERCENT)
{
// break, since elements are ordered by the module size deviation there cannot be
// any more interesting elements for the given p1.
break;
}
FinderPattern[] test = new FinderPattern[]{p1, p2, p3};
ResultPoint.orderBestPatterns(test);
// Calculate the distances: a = topleft-bottomleft, b=topleft-topright, c = diagonal
FinderPatternInfo info = new FinderPatternInfo(test);
float dA = ResultPoint.distance(info.TopLeft, info.BottomLeft);
float dC = ResultPoint.distance(info.TopRight, info.BottomLeft);
float dB = ResultPoint.distance(info.TopLeft, info.TopRight);
// Check the sizes
float estimatedModuleCount = ((dA + dB) / p1.EstimatedModuleSize) / 2;
if (estimatedModuleCount > MAX_MODULE_COUNT_PER_EDGE || estimatedModuleCount < MIN_MODULE_COUNT_PER_EDGE)
{
continue;
}
// Calculate the difference of the edge lengths in percent
float vABBC = System.Math.Abs(((dA - dB) / System.Math.Min(dA, dB)));
if (vABBC >= 0.1f)
{
continue;
}
// Calculate the diagonal length by assuming a 90° angle at topleft
//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 dCpy = (float) System.Math.Sqrt(dA * dA + dB * dB);
// Compare to the real distance in %
float vPyC = System.Math.Abs(((dC - dCpy) / System.Math.Min(dC, dCpy)));
if (vPyC >= 0.1f)
{
continue;
}
// All tests passed!
results.Add(test);
} // end iterate p3
} // end iterate p2
} // end iterate p1
if (!(results.Count == 0))
{
FinderPattern[][] resultArray = new FinderPattern[results.Count][];
for (int i = 0; i < results.Count; i++)
{
resultArray[i] = (FinderPattern[]) results[i];
}
return resultArray;
}
// Nothing found!
throw ReaderException.Instance;
}
/// <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()
{
System.Collections.ArrayList possibleCenters = PossibleCenters;
int size = possibleCenters.Count;
if (size < 3)
{
// Couldn't find enough finder patterns
throw ReaderException.Instance;
}
/*
* Begin HE modifications to safely detect multiple codes of equal size
*/
if (size == 3)
{
return(new FinderPattern[][] { new FinderPattern[] { (FinderPattern)possibleCenters[0], (FinderPattern)possibleCenters[1], (FinderPattern)possibleCenters[2] } });
}
// Sort by estimated module size to speed up the upcoming checks
Collections.insertionSort(possibleCenters, new ModuleSizeComparator());
/*
* Now lets start: build a list of tuples of three finder locations that
* - feature similar module sizes
* - are placed in a distance so the estimated module count is within the QR specification
* - have similar distance between upper left/right and left top/bottom finder patterns
* - form a triangle with 90° angle (checked by comparing top right/bottom left distance
* with pythagoras)
*
* Note: we allow each point to be used for more than one code region: this might seem
* counterintuitive at first, but the performance penalty is not that big. At this point,
* we cannot make a good quality decision whether the three finders actually represent
* a QR code, or are just by chance layouted so it looks like there might be a QR code there.
* So, if the layout seems right, lets have the decoder try to decode.
*/
System.Collections.ArrayList results = System.Collections.ArrayList.Synchronized(new System.Collections.ArrayList(10)); // holder for the results
for (int i1 = 0; i1 < (size - 2); i1++)
{
FinderPattern p1 = (FinderPattern)possibleCenters[i1];
if (p1 == null)
{
continue;
}
for (int i2 = i1 + 1; i2 < (size - 1); i2++)
{
FinderPattern p2 = (FinderPattern)possibleCenters[i2];
if (p2 == null)
{
continue;
}
// Compare the expected module sizes; if they are really off, skip
float vModSize12 = (p1.EstimatedModuleSize - p2.EstimatedModuleSize) / (System.Math.Min(p1.EstimatedModuleSize, p2.EstimatedModuleSize));
float vModSize12A = System.Math.Abs(p1.EstimatedModuleSize - p2.EstimatedModuleSize);
if (vModSize12A > DIFF_MODSIZE_CUTOFF && vModSize12 >= DIFF_MODSIZE_CUTOFF_PERCENT)
{
// break, since elements are ordered by the module size deviation there cannot be
// any more interesting elements for the given p1.
break;
}
for (int i3 = i2 + 1; i3 < size; i3++)
{
FinderPattern p3 = (FinderPattern)possibleCenters[i3];
if (p3 == null)
{
continue;
}
// Compare the expected module sizes; if they are really off, skip
float vModSize23 = (p2.EstimatedModuleSize - p3.EstimatedModuleSize) / (System.Math.Min(p2.EstimatedModuleSize, p3.EstimatedModuleSize));
float vModSize23A = System.Math.Abs(p2.EstimatedModuleSize - p3.EstimatedModuleSize);
if (vModSize23A > DIFF_MODSIZE_CUTOFF && vModSize23 >= DIFF_MODSIZE_CUTOFF_PERCENT)
{
// break, since elements are ordered by the module size deviation there cannot be
// any more interesting elements for the given p1.
break;
}
FinderPattern[] test = new FinderPattern[] { p1, p2, p3 };
ResultPoint.orderBestPatterns(test);
// Calculate the distances: a = topleft-bottomleft, b=topleft-topright, c = diagonal
FinderPatternInfo info = new FinderPatternInfo(test);
float dA = ResultPoint.distance(info.TopLeft, info.BottomLeft);
float dC = ResultPoint.distance(info.TopRight, info.BottomLeft);
float dB = ResultPoint.distance(info.TopLeft, info.TopRight);
// Check the sizes
float estimatedModuleCount = ((dA + dB) / p1.EstimatedModuleSize) / 2;
if (estimatedModuleCount > MAX_MODULE_COUNT_PER_EDGE || estimatedModuleCount < MIN_MODULE_COUNT_PER_EDGE)
{
continue;
}
// Calculate the difference of the edge lengths in percent
float vABBC = System.Math.Abs(((dA - dB) / System.Math.Min(dA, dB)));
if (vABBC >= 0.1f)
{
continue;
}
// Calculate the diagonal length by assuming a 90° angle at topleft
//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 dCpy = (float)System.Math.Sqrt(dA * dA + dB * dB);
// Compare to the real distance in %
float vPyC = System.Math.Abs(((dC - dCpy) / System.Math.Min(dC, dCpy)));
if (vPyC >= 0.1f)
{
continue;
}
// All tests passed!
results.Add(test);
} // end iterate p3
} // end iterate p2
} // end iterate p1
if (!(results.Count == 0))
{
FinderPattern[][] resultArray = new FinderPattern[results.Count][];
for (int i = 0; i < results.Count; i++)
{
resultArray[i] = (FinderPattern[])results[i];
}
return(resultArray);
}
// Nothing found!
throw ReaderException.Instance;
}
