public void GetsTheCoordinatesOfAllPixelsOnALineDefinedByAStartingPointAndAngle0(
string testcaseName,
int angle,
MatrixPosition[] expectedResult)
{
//// [ (0,0) (0,1) (0,2) (0,3) (0,4) (0,5) (0,6) (0,7) (0,8) (0,9) ]
//// [ (1,0) (1,1) (1,2) (1,3) (1,4) (1,5) (1,6) (1,7) (1,8) (1,9) ]
//// [ (2,0) (2,1) (2,2) (2,3) (2,4) (2,5) (2,6) (2,7) (2,8) (2,9) ]
//// [ (3,0) (3,1) (3,2) (3,3) (3,4) (3,5) (3,6) (3,7) (3,8) (3,9) ]
//// [ (4,0) (4,1) (4,2) (4,3) (4,4) (4,5) (4,6) (4,7) (4,8) (4,9) ]
//// [ (5,0) (5,1) (5,2) (5,3) (5,4) X (5,6) (5,7) (5,8) (5,9) ] x = Starting Point (m,n)
//// [ (6,0) (6,1) (6,2) (6,3) (6,4) (6,5) (6,6) (6,7) (6,8) (6,9) ]
//// [ (7,0) (7,1) (7,2) (7,3) (7,4) (7,5) (7,6) (7,7) (7,8) (7,9) ]
//// [ (8,0) (8,1) (8,2) (8,3) (8,4) (8,5) (8,6) (8,7) (8,8) (8,9) ]
//// [ (9,0) (9,1) (9,2) (9,3) (9,4) (9,5) (9,6) (9,7) (9,8) (9,9) ]
var inputImage = new BinaryImage(10, 10);
var startingPoint = new MatrixPosition(5, 5);
var result = SignatureReader.GetSamplingLineForAngle(
inputImage,
startingPoint,
angle);
var resultingPositions = result.SamplingPoints.Select(x => x.Position).ToArray();
resultingPositions.Should().ContainInOrder(expectedResult, testcaseName);
resultingPositions.Should().HaveCount(expectedResult.Length);
}
private static bool IsPositionWithinImage(BinaryImage image, MatrixPosition position)
{
return(position.M >= 0 &&
position.N >= 0 &&
position.M < image.Size.Height &&
position.N < image.Size.Width);
}
public void ShrinksImagesToHalfItsSize()
{
var sampleImage = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0, 0, 0, 0 },
{ 0, 1, 1, 1, 1, 0 },
{ 0, 1, 1, 1, 1, 0 },
{ 0, 1, 1, 1, 1, 0 },
{ 0, 1, 1, 1, 1, 0 },
{ 0, 0, 0, 0, 0, 0 },
});
var expected = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0 },
{ 0, 1, 0 },
{ 0, 0, 0 },
});
var result = Shrinker.ShrinkByHalf(sampleImage);
result.Should().Be(expected,
$"result:\r\n{result.ToMatrixString()}\r\n should be as expected:\r\n{expected.ToMatrixString()}");
}
public void InterpretsMatrixCoordinatesCorrectly()
{
var sampleImage = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 1, 0 },
{ 1, 0, 1 },
{ 1, 0, 0 }
});
// first row
int m = 0;
sampleImage[m, 0].Should().Be(BinaryImage.White);
sampleImage[m, 1].Should().Be(BinaryImage.Black);
sampleImage[m, 2].Should().Be(BinaryImage.White);
// second row: m=1
m = 1;
sampleImage[m, 0].Should().Be(BinaryImage.Black);
sampleImage[m, 1].Should().Be(BinaryImage.White);
sampleImage[m, 2].Should().Be(BinaryImage.Black);
// third row: m=2
m = 2;
sampleImage[m, 0].Should().Be(BinaryImage.Black);
sampleImage[m, 1].Should().Be(BinaryImage.White);
sampleImage[m, 2].Should().Be(BinaryImage.White);
}
/// <summary>
/// Returns the coordinates of the pixels that lie on the sampling line, which is defined by the
/// <paramref name="startingPosition"/> and its <paramref name="angle"/> to the edge of the
/// <paramref name="image"/>. The <paramref name="startingPosition"/> will not be returned in the
/// result set.
/// </summary>
/// <remarks>
/// <example>
/// Here's an example using the angle of 45 degrees.
/// <![CDATA[
/// ^
/// | E E = edge of the image
/// | \ \ = sampling line
/// | \ c = center
/// | \
/// | \
/// | \
/// | c
/// |
/// .
/// .
/// . --------------------------->
/// ]]>
/// </example>
/// </remarks>
internal static SamplingLine GetSamplingLineForAngle(
BinaryImage image,
MatrixPosition startingPosition,
int angle)
{
const int MaxIterationLimit = 50000;
var samplingLine = new SamplingLine();
MatrixPosition nextPosition;
double phi = (angle + 180d) * Math.PI / 180d;
int r = 1;
do
{
var deltaN = (int)Math.Round(r * Math.Cos(phi), 0, MidpointRounding.ToZero);
var deltaM = (int)Math.Round(r * Math.Sin(phi), 0, MidpointRounding.ToZero);
nextPosition = new MatrixPosition(startingPosition.M + deltaM, startingPosition.N + deltaN);
if (nextPosition != startingPosition
// ReSharper disable once SimplifyLinqExpressionUseAll
&& !samplingLine.ContainsPosition(nextPosition) &&
IsPositionWithinImage(image, nextPosition))
{
var pointOfInterest = new SamplingPoint(nextPosition, r);
samplingLine.Add(pointOfInterest);
}
r++;
} while (IsPositionWithinImage(image, nextPosition) && r < MaxIterationLimit);
return(samplingLine);
}
public void AppliesThinningOnImage()
{
var structuringElement = new StructuringElement(
new[, ]
{
{ 0, 0, -1 },
{ 1, 1, -1 },
{ -1, -1, -1 }
});
var inputImage = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0 },
{ 1, 1, 1 },
{ 1, 1, 1 }
});
var expected = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0 },
{ 1, 0, 0 },
{ 1, 1, 1 }
});
var structuringElements = new[] { structuringElement };
var result = Thinner.Thinning(inputImage, structuringElements);
result.Should().Be(
expected,
$"result:\r\n{result.ToMatrixString()}\r\n should be as expected:\r\n{expected.ToMatrixString()}");
}
/// <summary>
/// Shrinks the <paramref name="image"/> by half its size and returns the new image as result.
/// </summary>
internal static BinaryImage ShrinkByHalf(BinaryImage image)
{
var downSizedImage = new BinaryImage(image.Size.Width / 2, image.Size.Height / 2);
var matrixSize = new Size(2, 2);
Parallel.For(
0,
downSizedImage.Size.Height,
downSizedM =>
{
int originalM = downSizedM * 2;
for (int downSizedN = 0; downSizedN < downSizedImage.Size.Width; downSizedN++)
{
int originalN = downSizedN * 2;
var positionInImage = new MatrixPosition(originalM, originalN);
var neighbourMatrixFromPosition =
image.GetNeighborMatrixFromPosition(positionInImage, matrixSize);
float averageValue = neighbourMatrixFromPosition.GetAverageValue();
downSizedImage[downSizedM, downSizedN] = averageValue >= 0.75f
? BinaryImage.Black
: BinaryImage.White;
}
});
return(downSizedImage);
}
private static IEnumerable <int> FindAllBlackPixelsOnSamplingLine(
BinaryImage image,
SamplingLine samplingLine)
{
return(from samplingPoints in samplingLine.SamplingPoints
where image[samplingPoints.Position] == BinaryImage.Black
select samplingPoints.Radius);
}
public void GetsNeighbourMatrixFromPosition(
BinaryImage binaryImage,
MatrixPosition positionInImage,
Size sizeOfNeighbourMatrix,
BinaryMatrix expectedResult)
{
var result = binaryImage.GetNeighborMatrixFromPosition(positionInImage, sizeOfNeighbourMatrix);
result.Should().Be(expectedResult);
}
public void VerifySignatureWith360SamplingPointsOfNumber1MatchesFittingTemplate()
{
var signature01Image = BinaryImage.FromImage(TestDataResources.calculatedSign360_01);
var template01Image = BinaryImage.FromImage(TestDataResources.signatureTemplate360_01);
var template02Image = BinaryImage.FromImage(TestDataResources.signatureTemplate360_02);
bool firstResult = SignatureMatcher.IsMatch(signature01Image, template01Image);
bool secondResult = SignatureMatcher.IsMatch(signature01Image, template02Image);
firstResult.Should().BeTrue("signature of number 1 should match template of number 1");
secondResult.Should().BeFalse("signature of number 1 must not match template of number 2");
}
/// <summary>
/// Gets the center of the object in <paramref name="image"/>.
/// </summary>
internal static MatrixPosition GetCenterOfObjectIn(BinaryImage image)
{
int leftMostPoint = image.FindLeftMostPixelIn();
int rightMostPoint = image.FindRightMostPixelIn();
int centerNPoint = (leftMostPoint + rightMostPoint) / 2;
int topMostPoint = image.FindTopMostPixelPosition();
int bottomLinePoint = image.FindBottomLinePixelIn();
int centerMPoint = (topMostPoint + bottomLinePoint) / 2;
return(new MatrixPosition(centerMPoint, centerNPoint));
}
public void CanConvertImagesToBinaryImageAndBack()
{
var signature01Image = BinaryImage.FromImage(TestDataResources.calculatedSign360_01);
signature01Image.IsEmpty().Should().BeFalse("signature must not be empty");
var converted = signature01Image.ToBitmap();
var convertedBackSignature01Image = BinaryImage.FromImage(converted);
convertedBackSignature01Image.IsEmpty().Should().BeFalse("signature must not be empty");
signature01Image.Should().Be(convertedBackSignature01Image);
}
public void CanConvertSignatureTemplateImagesToBinaryImageAndBack()
{
var templateImage = BinaryImage.FromImage(TestDataResources.signatureTemplate360_00);
templateImage.IsEmpty().Should().BeFalse("signature template must not be empty");
var converted = templateImage.ToBitmap();
var convertedBackImage = BinaryImage.FromImage(converted);
convertedBackImage.IsEmpty().Should().BeFalse("signature template must not be empty");
templateImage.Should().Be(convertedBackImage);
}
public void ClonesImages()
{
var firstImage = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0 },
{ 1, 1, 0 },
{ 0, 0, 1 }
});
var secondImage = firstImage.Clone();
firstImage.Should().Be(secondImage);
}
public void WritesImageToMatrixString()
{
const string Expected = "010\r\n110\r\n001";
var sampleImage = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 1, 0 },
{ 1, 1, 0 },
{ 0, 0, 1 }
});
string result = sampleImage.ToMatrixString();
result.Should().Be(Expected);
}
public void CanReadSignatureTemplates()
{
var binaryImage = BinaryImage.FromImage(TestDataResources.sampleSignTemplate);
string test = binaryImage.ToMatrixString();
test.Should().Be(
"1111100" + Environment.NewLine +
"1111000" + Environment.NewLine +
"1111000" + Environment.NewLine +
"1111000" + Environment.NewLine +
"1110000" + Environment.NewLine +
"1110000" + Environment.NewLine +
"1100000" + Environment.NewLine +
"1100000" + Environment.NewLine +
"1000000");
}
public void GetNeighborMatrixFromPosition()
{
var sampleImage = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0, 0, 0, 0 },
{ 0, 1, 1, 1, 1, 0 },
{ 0, 1, 1, 1, 1, 0 },
{ 0, 1, 1, 1, 1, 0 },
{ 0, 1, 1, 1, 1, 0 },
{ 0, 0, 0, 0, 0, 0 },
});
sampleImage.GetNeighborMatrixFromPosition(0, 0, 2).ToString().Should().Be("00\r\n01");
sampleImage.GetNeighborMatrixFromPosition(1, 0, 2).ToString().Should().Be("01\r\n01");
sampleImage.GetNeighborMatrixFromPosition(0, 1, 2).ToString().Should().Be("00\r\n11");
sampleImage.GetNeighborMatrixFromPosition(1, 1, 2).ToString().Should().Be("11\r\n11");
}
/// <summary>
/// Gets the signature of an object in <paramref name="image"/> by using a variable number of sampling lines.
/// </summary>
/// <returns>
/// The coordinates of the signature points in an ordered list.
/// The key of the dictionary represents the index of the sampling point.
/// The value represents the radius from the center of all pixels found.
/// </returns>
internal static ShapeSignature GetSignature(BinaryImage image, int numberOfSamplingLines)
{
CheckNumberOfSamplingLinesIsInRange(numberOfSamplingLines);
var signature = new ShapeSignature(numberOfSamplingLines);
int samplingIndex = 0;
var samplingLines = GetSamplingLines(image, numberOfSamplingLines);
foreach (var samplingLine in samplingLines)
{
int[] pointsInAngle = FindAllBlackPixelsOnSamplingLine(image, samplingLine).ToArray();
signature.Add(samplingIndex, pointsInAngle);
samplingIndex++;
}
return(signature);
}
internal static Bitmap Plot(BinaryImage sourceImage, IEnumerable <SamplingLine> samplingLines)
{
const int BitsPerByte = 8;
var sourceImageBmp = sourceImage.ToBitmap();
var rectangle = new Rectangle(0, 0, sourceImageBmp.Width, sourceImageBmp.Height);
var bitmapData = sourceImageBmp.LockBits(
rectangle,
ImageLockMode.WriteOnly,
sourceImageBmp.PixelFormat);
var bytesPerPixel = Image.GetPixelFormatSize(sourceImageBmp.PixelFormat) / BitsPerByte;
unsafe
{
var ptrFirstPixel = (byte *)bitmapData.Scan0;
foreach (var samplingLine in samplingLines)
{
foreach (var samplingPoint in samplingLine.SamplingPoints)
{
int m = samplingPoint.Position.M;
int n = samplingPoint.Position.N;
var byteX = n * bytesPerPixel;
var ptrCurrentLine = ptrFirstPixel + (m * bitmapData.Stride);
if (sourceImage[m, n] == BinaryImage.Black)
{
ptrCurrentLine[byteX] = Hit.B; // blue
ptrCurrentLine[byteX + 1] = Hit.G; // green
ptrCurrentLine[byteX + 2] = Hit.R; // red
}
else
{
ptrCurrentLine[byteX] = Miss.B; // blue
ptrCurrentLine[byteX + 1] = Miss.G; // green
ptrCurrentLine[byteX + 2] = Miss.R; // red
}
}
}
}
sourceImageBmp.UnlockBits(bitmapData);
return(sourceImageBmp);
}
internal static BinaryImage Plot(ShapeSignature signature)
{
int[][] signaturePoints = signature.Get();
int largestRadius = FindLargestRadiusIn(signature);
var image = new BinaryImage(signature.NumberOfSamplingPoints, largestRadius + 3);
for (int i = 0; i < signature.NumberOfSamplingPoints; i++)
{
int[] pointInAngle = signaturePoints[i];
for (int j = 0; j < pointInAngle.Length; j++)
{
int radius = pointInAngle[j];
image[radius, i] = BinaryImage.Black;
}
}
return(image);
}
public void ComparesTwoImages()
{
var firstImage = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0 },
{ 0, 1, 0 },
{ 0, 0, 0 }
});
var secondImage = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0 },
{ 0, 1, 0 },
{ 0, 0, 0 }
});
firstImage.Should().Be(secondImage);
}
internal static IReadOnlyCollection <SamplingLine> GetSamplingLines(BinaryImage image, int numberOfSamplingLines)
{
CheckNumberOfSamplingLinesIsInRange(numberOfSamplingLines);
double angleIncrement = 360d / numberOfSamplingLines;
var samplingLines = new SamplingLine[numberOfSamplingLines];
var center = GetCenterOfObjectIn(image);
for (int samplingIndex = 0; samplingIndex < numberOfSamplingLines; samplingIndex++)
{
// value of the angle, at which the sampling from the center will be taken.
int angle = (int)Math.Round(samplingIndex * angleIncrement, 0, MidpointRounding.ToZero);
var samplingLine = GetSamplingLineForAngle(image, center, angle);
samplingLines[samplingIndex] = samplingLine;
}
return(samplingLines);
}
/// <summary>
/// Applies a smooth filter on <paramref name="binaryImage"/> to remove noise and create
/// more distinguishable lines.
/// </summary>
public static BinaryImage Smoothing(BinaryImage binaryImage)
{
// Defines the size of the matrix used to remove the noises in a black and white image.
// NOTE: the size should be at least 3 and an odd number
const int MatrixSize = 7;
// Needed for edge cases of the image border.
const int MatrixRadius = MatrixSize / 2;
var img = binaryImage.Clone();
Parallel.For(
MatrixRadius,
img.Size.Height - MatrixRadius,
m =>
{
for (int n = MatrixRadius; n < img.Size.Width - MatrixRadius; n++)
{
// 1 1 0
// 1 x 0 -> x is the average of all values around.
// 0 0 0
var matrixColors = new BinaryMatrix(new Size(MatrixSize, MatrixSize));
for (var matrixM = 0; matrixM < MatrixSize; matrixM++)
{
for (var matrixN = 0; matrixN < MatrixSize; matrixN++)
{
int imageM = m - MatrixRadius + matrixM;
int imageN = n - MatrixRadius + matrixN;
matrixColors[matrixM, matrixN] = img[imageM, imageN];
}
}
float average = matrixColors.GetAverageValue();
img[m, n] = average >= 0.5f ? BinaryImage.Black : BinaryImage.White;
}
});
return(img);
}
public void CropsLargeImages()
{
var sampleImage = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 1, 1, 0, 0 },
{ 0, 0, 0, 0, 1, 1, 1, 0, 0 },
{ 0, 0, 0, 1, 1, 1, 1, 0, 0 },
{ 0, 0, 0, 0, 1, 1, 1, 0, 0 },
{ 0, 0, 0, 0, 0, 1, 1, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0 }
});
var expected = BinaryImage.FromByteArray(
new byte[, ]
{
{ 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 1, 1, 0, 0 },
{ 0, 0, 0, 1, 1, 1, 0, 0 },
{ 0, 0, 1, 1, 1, 1, 0, 0 },
{ 0, 0, 0, 1, 1, 1, 0, 0 },
{ 0, 0, 0, 0, 1, 1, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0 }
});
var result = Cropper.CropAroundFigures(sampleImage);
result.Should().Be(expected);
}
public static BinaryImage DownSizeToHalf(BinaryImage binaryImage)
{
return(Shrinker.ShrinkByHalf(binaryImage));
}
public static BinaryImage CropAroundFigures(BinaryImage binaryImage)
{
return(Cropper.CropAroundFigures(binaryImage));
}
public static BinaryImage Thinning(BinaryImage binaryImage)
{
return(Thinner.Thinning(binaryImage));
}
public static BinaryImage GetSignatureIn(BinaryImage binaryImage, int samplingRate = 180)
{
var signature = SignatureReader.GetSignature(binaryImage, samplingRate);
return(SignaturePlotter.Plot(signature));
}
public static bool VerifyIfSignatureMatchesToTemplate(BinaryImage signatureImage, BinaryImage templateImage)
{
return(SignatureMatcher.IsMatch(signatureImage, templateImage));
}