Changes DIPlib 3.0 beta 5

DIPlib 3 is a complete rewrite in C++ of the DIPlib 2 infrastructure, which was written in C; only the code that implements actual image processing and analysis algorithms is ported over.

Here we list the changes to DIPlib as compared to version 2.9. The list below describes infrastructure changes, function interface changes, and functionality changes in the DIPlib library. It is possible that we missed some changes here, but hopefully this list will help in porting your old code that used DIPlib to the new version.

Core/infrastructure changes

• Functions and types used to start with dip_, now they are in the dip:: namespace.

• Functions no longer return a dip_Error, they throw an exception instead. The DIPXJ et al. macros are gone. So are the DIP_FNR_DECLARE / DIP_FNR_INITIALISE / DIP_FNR_EXIT macros.

• The array types are now based on either std::vector or dip::DimensionArray, which is a short-array optimized version of std::vector with a bunch of specialized algorithms as member functions. Consequently, all access functions are no longer, to be replaced by methods with different names and syntax.

• The core image class, dip_Image, now is dip::Image, with a much simplified interface. As with the array types, access functions are no longer, to be replaced by class methods. Many of these class methods have names similar to the original access functions, but not always. For example, dip_ImageSetStride now is dip::Image::SetStrides.

  • dip_Assimilate is the dip::Image::ReForge method.

  • We used to call the image size its dimension. dip_Dimensions is now dip::Image::Sizes. The reason is that it was too confusing talking about a dimension as an image axis (the 2^nd dimension), and the dimension of that dimension (the size of the image along that axis).

  • Images now can have a tensor as pixel value, as was possible in DIPimage. To port old functions, you can test for dip::Image::IsScalar and ignore this new feature, or modify the old function to work with tensor values.

  • Images now carry the physical dimension in them (referred to as pixel size). When porting functions, think about whether this data needs to be maintained, modified, or removed.

  • The same is true for the color space. A function that changes the number of tensor elements must also remove the color space information.

  • We have added 64-bit signed and unsigned integers to the set of allowed data types for pixels.

  • Please read the documentation to the dip::Image class before doing any work with the library!

• The framework functions all have different names:
  • dip_SeparableFrameWork → dip::Framework::Separable
  • dip_MonadicFrameWork → dip::Framework::ScanMonadic / dip::Framework::SeparableMonadic
  • dip_MonadicPoint → dip::Framework::ScanMonadic
  • dip_MonadicPointData → dip::Framework::ScanMonadic
  • dip_PixelTableArrayFrameWork → doesn’t exist any more, was used meaningfully only in dip_GeneralisedKuwaharaImproved
  • dip_PixelTableFrameWork → dip::Framework::Full
  • dip_ScanFrameWork → dip::Framework::Scan() / dip::Framework::ScanDyadic
  • dip_SingleOutputFrameWork → dip::Framework::ScanSingleOutput
  • dip_SingleOutputPoint → dip::Framework::ScanSingleOutput

  Their interfaces are not exactly compatible, but it should be relatively straightforward to port old line functions to use the new framework, yielding shorter code. However, all line functions are now expected to use strides.

• dip_ovl.h is now diplib/overload.h, and works like a normal header file defining macros to use in your code. dip_tpi.h is gone, the template strategy to define overloaded functions is now based on C++ templates, yielding code that is easier to write and easier to read.

• There is no longer a dip_Initialise function. There are no registries. There is only one global variable: the number of threads to use with OpenMP (see dip::GetNumberOfThreads and dip::SetNumberOfThreads).

• There is no longer a dip_ImagesSeparate function. Its functionality can be accomplished using a simple image copy (the copy shares the image data with the original image, and makes it possible to strip the original image while still keeping the input data available).

• Header files used to have names such as dip_xxx.h, they now are diplib/xxx.h. The “xxx” part has remained the same in most cases, though some function declarations have moved to a different header file. The documentation specifies which header file to include for each function.

• The dipIO library no longer exists. Some dipio_Xxx functions are now defined in the diplib/file_io.h header file (reading and writing ICS, TIFF and JPEG files). dipio_MeasurementWriteCSV is is diplib/measurement.h. dipio_Colour2Gray functionality is replaced by dip::ColorSpaceManager. Other functionality no longer exists.

Changes in algorithm interface

• Function parameters expressing options are now represented by strings rather than #define or enum constants (except for low-level library functionality).

• The library now makes a distinction between signed and unsigned integers. This affects many function parameters.

• Output arguments are now always on the left-hand side, except for output images.

• We try to sort the arguments most commonly left with default values at the end of the argument lists. This caused some functions to have a different parameter order. For example, the boundary condition is not commonly changed, and so the boundary condition array input argument is now typically further to the right in (usually at the end of) the argument list.

• Function names are often simplified, since in C++ it’s possible to overload functions for different types. For example, dip_BesselJ0 and dipm_BesselJ0 are now both called dip::BesselJ0. dip_BooleanArrayUseParameter, dip_IntegerArrayUseParameter, etc. are now all dip::ArrayUseParameter.

• Some other function names that included only parts of a name or verb (they were shortened) have been renamed to use full names. For example: dip_Sub is now dip::Subtract; dip_LaplaceMinDgg is now called dip::LaplaceMinusDgg; dip_RadialMin and dip_RadialMax are now called dip::RadialMinimum and dip::RadialMaximum.

• dip_Measure is now dip::MeasurementTool::Measure, with dip::MeasurementTool an object that knows about defined measurement features.

  • Measurement features are registered with a dip::MeasurementTool object, not in the global registry.

  • Measurement features have a much simpler programmer’s interface, it should be easier to write new features now.

  • Computed measurements are now in an object of type dip::Measurement, whose interface is much easier to use than the old dip_Measurement.

• dip_ObjectToMeasurement now takes a feature iterator rather than computing the feature; this might be more flexible.

• dip_Arith and dip_Compare used to implement all arithmetic and comparison operators, (with convenience macros dip_Add, dip_Sub, etc.). These functions no longer exist, each operator is implemented by its own function. The shortened names of these functions are no longer shortened, so instead of dip_Sub use dip::Subtract. dip_AddInteger, dip_AddFloat, etc. now are overloaded versions of dip::Add et al.

• dip_WeightedAdd is now generalized to dip::LinearCombination. dip_WeightedSub can be emulated by setting a negative weight. dip_WeightedMul and dip_WeightedDiv were not used anywhere, and don’t seem very useful.

• Morphological filters now use a dip::StructuringElement to collect three parameters of DIPlib 2. Other filters that had a filter shape argument now use a dip::Kernel to collect three parameters.

• dip_Min and dip_Max are now dip::Infimum and dip::Supremum, and dip_SignedMinimum is now dip::SignedInfimum. There are too many functions with “Maximum” and “Minimum” in their name.

• dip_MultiDimensionalHistogram and dip_ImageToHistogram have been merged into the constructor for dip::Histogram, which replaces dip_Histogram.

• dip::Distribution is a new class that replaces dip_Distribution. dip_Distribution was identical to dip_Histogram. dip::Distribution is very different from dip::Histogram.

• The dip_ImageLookup function has been merged with the dip::LookupTable object, and includes the functionality of dip_ImageLut.

• dip_Threshold is now dip::FixedThreshold. dip::Threshold is a function that allows to select an automated threshold method.

• dip_RandomXxx functions are now methods to the dip::Random class. dip_UniformRandomVariable and similar functions are now classes dip::UniformRandomGenerator and similar. dip::GaussianRandomGenerator produces a single output value, the object stores the second value for the next call.

• dip_LabelSetBorder, dip_ImageDoEdge and dip_PlaneDoEdge are merged into dip::SetBorder, which additionally can specify the border size.

• dip_LocalMinima is now called dip::WatershedMinima. There’s also a maxima variant.

• dip_GetMaximumAndMinimum is now called dip::MaximumAndMinimum for consistency.

• dip_ResamplingFT is no longer a separate function, call dip::Resampling with "ft" as method. dip_Skewing was renamed to dip::Skew for consistency. dip_Rotation has been renamed dip::Rotation2D, and a generalized dip::Rotation is similar but takes two additional integers to specify the rotation plane. dip_Rotation3d_Axis and dip_Rotation3d are now both called dip::Rotation3D, their argument types are different. dip::Resampling, dip::Skew, dip::Rotation and similar now take a boundary condition as optional argument. dip::Skew has a new parameter that allows selection of the image line that has 0 shift. dip::Rotation now rotates around the pixel at the origin (this is the pixel to the right of the geometric center for even-sized images), rather than the geometric center of the image.

• dip_Rotation2d90, dip_Rotation2d90, dip_Map, dip_Mirror, and dip_Crop are now all member functions of dip::Image, and modify the existing image (without copying data). dip_GetSlice, dip_PutSlice, dip_PutSubSpace, dip_GetLine, dip_PutLine, dip_Set, dip_SetXxx, dip_Get, dip_GetXxx are now all implemented through indexing operations on the dip::Image object (see the many overloads of dip::Image::At) and assignment to the output of these operations.

• dip_KuwaharaImproved is now called dip::Kuwahara, and dip_Kuwahara is no longer (C++ default values make it redundant).

• dip_GeneralisedKuwaharaImproved is now called dip::SelectionFilter, and dip_GeneralisedKuwahara is no longer (C++ default values make it redundant).

• dip_PaintBox, dip_PaintDiamond and dip_PaintEllipsoid are now called dip::DrawBox, dip::DrawDiamond and dip::DrawEllipsoid, respectively (for consistency). dip_DrawLineFloat and dip_DrawLineComplex are now a single function dip::DrawLine; the same is true for dip::DrawLines.

• dip_RadialDistribution renamed to dip::DistanceDistribution.

• dip_Bilateral renamed to dip::SeparableBilateralFilter, and dip_BilateralFilter renamed to dip::FullBilateralFilter. Added new function dip::BilateralFilter as an interface to all bilateral filter variants.

• dip_TestObjectCreate, dip_TestObjectModulate, dip_TestObjectBlur and dip_TestObjectAddNoise have been merged into a single function: dip::TestObject. The new function additionally has the option to generate test objects with Gaussian edges directly in the spatial domain.

• dip_GenerateRamp is now dip::CreateRamp, and has convenience functions dip::FillRamp, dip::FillXCoordinate, dip::CreateXCoordinate, dip::FillYCoordinate, dip::CreateYCoordinate, dip::FillZCoordinate, dip::CreateZCoordinate.

• dip::EuclideanDistanceToPoint and friends now take the sizes of the output image to create. They are generalized in the functions dip::DistanceToPoint and dip::FillDistanceToPoint.

• dip::ClipLow and dip::ClipHigh are convenience interfaces to dip::Clip.

Changes in functionality

• Second order extrapolation boundary extension didn’t do as advertised in DIPlib 2. Also the first order extrapolation didn’t work correctly with unsigned integers. The new implementation fits a 1^st or 2^nd order polynomial that reaches 0 at the end of the extended boundary, with the 2^nd order polynomial matching two samples at the image edge and therefore connects smoothly. A 3^rd order extrapolation has been added, which works similarly to the 2^nd order extrapolation but reaches 0 smoothly at the end of the boundary. These functions are quite noise sensitive, however, and produce high frequencies along the edge.

• The mirror and asymmetric boundary extension methods have been fixed to work correctly when the boundary is larger than the image. Mirror no longer repeats the pixel at the edge of the image.

• Fixed little bug in the “Perimeter” measurement feature, which didn’t check the corner count for the transition from the last to the first chain code, yielding a perimeter that was often 0.0910 pixels too long. The feature “Radius” now computes the center of mass of the object correctly.

• The measurement features “Skewness” and “ExcessKurtosis” are no longer separate features, but instead put together in the new “Statistics” feature, which also computes the mean and standard deviation. The measurement feature “StdDev” is now called “StandardDeviation”. The algorithms to compute these statistics have changed to be more stable. The measurement feature “Sum” was an alias to “Mass”, and is not (yet?) available.

• The measurement feature “Convexity” has been renamed to “Solidity”, the more common name for the ratio of area to convex area.

• New measurement features: “SolidArea”, “Circularity”, “Convexity”, “Eccentricity”, “EllipseVariance”, “Roundness”, “DimensionsCube”, “DimensionsEllipsoid”, “GreyDimensionsCube” and “GreyDimensionsEllipsoid”. Note that “Convexity” therefore is not the same as what it was in the previous version of the library.

• The measurement features “Mu”, “Inertia”, “MajorAxes”, and their grey-value versions have been generalized to arbitrary number of dimensions.

• dip::SeparableConvolution treats input filter definitions slightly differently, and there no longer are left and right options.

• dip::ImageDisplay no longer does any spatial scaling. Also, it’s a class, not a function, and provides much more functionality than the function of the same name in the old version of the library.

• dip::ColorSpaceManager is functionality ported from MATLAB-code in DIPimage 2, with a few new color spaces added.

• dip::FourierTransform now does normalization in the more common way (forward transform not normalized, inverse transform normalized by 1/N), but an option ("symmetric") allows to change the normalization to be consistent with DIPlib 2, which used a symmetric normalization scheme (both forward and backward transforms use 1/N^1/2). It also has options to specify where the origin of the transform is ("corner") and for padding to a nice size ("fast").

• dip::Histogram misses a few of the options that dip_MultiDimensionalHistogram had, but I don’t think they are relevant. They can be added easily if necessary. Histograms now use 64-bit unsigned integers for the bins. It is possible to add histograms together.

• Many threshold selection strategies have been ported from MATLAB code in DIPimage, see dip::Threshold.

• dip::Random uses a different pseudo-random number generator. Previous versions used the Mersenne Twister. We now use the PCG scheme (permuted linear congruential generator), which is much faster than the Mersenne Twister, has a much smaller internal state, and produces better quality randomness, though with the given parameters, the period is not as large as that of the Mersenne Twister (2¹²⁸ vs 2¹⁹⁹³⁷, but do note that 2¹²⁸ is a very, very long period).

• Morphological filters define line structuring elements differently than before. They used to be available only for 2D images, now they are generalized to nD. The filter parameter, instead of being a length and an angle, now represents the bounding box, with direction encoded by the signs. Besides the discrete line and the interpolated line, we now have several other options, including the periodic line, which makes translation-invariant operations with line SEs much more efficient. The "diamond" SE is now implemented using line SEs, and we have added an "octagonal" SE that is computed as a combination of a diamond SE and a rectangular SE.

• dip::Rotation and dependent functions now rotate around the pixel that is right from center (the same pixel that is assumed the origin in dip::FourierTransform and other functions), instead of the point in between pixels, in case of an even-sized image. The implementation is slightly more complex, but this definition is more useful. This function now works for any number of dimensions, though it only rotates around one cartesian axis. dip::Rotation3D is a new function that does a full 3D rotation.

• dip::Skew can now skew in multiple dimensions at the same time.

• dip::Shift now calls dip::Resampling, shifting the image in the spatial domain. dip::ShiftFT uses the frequency domain, as dip_Shift did.

• dip::Resampling (and by extension dip::Shift) shifts the image in the opposite direction from what it did in DIPlib 2, where the shift was unintuitive.

• dip::FindShift now returns the shift with inverse sign compared to before, to match the reversal in dip::Shift.

• dip::Label now returns an unsigend integer image (previously it was a signed integer image). All functions that work on labeled images expect an unsigned integer image as input.

• dip::ImageWriteICS now has a "fast" option that causes dimensions to be written to file in the order in which they are stored in memory, rather than in standard increasing order. This makes writing a lot faster if strides are non-standard. dip::ImageReadICS has a similar option that re-orders strides for the output image to match those of the file, again potentially decreasing reading times significantly.

• dip::Canny and dip::MaximumSuppression have been generalized from 2D only to any number of dimensions.

• dip::GreyWeightedDistanceTransform now works for images of any dimensionality, and no longer excludes the pixels at the edge of the image. It also accepts an optional mask image. The Euclidean distance output argument has been merged with the grey-weighted distance output, a flag is used to choose which of these two outputs should be given. By default, it now uses the fast marching algorithm, which produces more isotropic results than the old algorithm.

• dip::GrowRegions no longer takes a grey-value image as input. Use dip::SeededWatershed instead.

• dip::EuclideanDistanceTransform has a new algorithm which produces exact distances in nD, and is parallelized and very fast. This new algorithm is the default.

• dip::ResampleAt has various signatures and a lot more flexibility than in the old library. There is also a dip::ResampleAtUnchecked, to be used together with dip::PrepareResampleAtUnchecked, for low-level use.

• dip::OrientationSpace is a simplified version of the old dip_OrientationSpace and dip_ExtendedOrientationSpace, with only the most useful options.

• Documented functions not (yet) ported: dip_AdaptivePercentile, dip_BiasedSigma, dip_GaussianSigma, dip_HartleyTransform, dip_PseudoInverse, dip_Sigma, dip_TikhonovMiller, dip_TikhonovRegularizationParameter, and dip_UpperEnvelope. It is unlikely that these will be ported, unless someone really needs them.

New functionality

• New external library DIPviewer adds interactive image display, see its documentation.

• New external library DIPjavaio adds the option to use Bio-Formats to read hundreds of image file formats, see its documentation.

• New analysis functions: dip::AutoCorrelationFT, dip::MeanShift, dip::FourierMellinMatch2D, dip::MonogenicSignal, dip::MonogenicSignalAnalysis, dip::Semivariogram, dip::Granulometry, dip::FractalDimension.

• New detection functions: dip::HoughTransformCircleCenters, dip::FindHoughMaxima, dip::PointDistanceDistribution, dip::FindHoughCircles, dip::RadonTransformCircles, dip::HarrisCornerDetector, dip::ShiTomasiCornerDetector, dip::NobleCornerDetector, dip::WangBradyCornerDetector, dip::FrangiVesselness, dip::MatchedFiltersLineDetector2D, dip::DanielssonLineDetector, dip::RORPOLineDetector.

• New display functions: dip::ApplyColorMap, dip::Overlay, dip::MarkLabelEdges.

• New distance function: dip::GeodesicDistanceTransform.

• New binary filtering functions: dip::FillHoles, dip::ConditionalThickening2D, dip::ConditionalThinning2D, dip::BinaryAreaOpening, dip::BinaryAreaClosing, dip::CountNeighbors, dip::MajorityVote, dip::GetSinglePixels, dip::GetEndPixels, dip::GetLinkPixels, dip::GetBranchPixels, dip::SupGenerating, dip::InfGenerating, dip::UnionSupGenerating, dip::UnionSupGenerating2D, dip::IntersectionInfGenerating, dip::IntersectionInfGenerating2D, dip::Thickening, dip::Thickening2D, dip::Thinning, dip::Thinning2D, dip::HomotopicThinningInterval2D, dip::HomotopicThickeningInterval2D, dip::EndPixelInterval2D, dip::HomotopicEndPixelInterval2D, dip::HomotopicInverseEndPixelInterval2D, dip::SinglePixelInterval, dip::BranchPixelInterval2D, dip::BoundaryPixelInterval2D, dip::ConvexHullInterval2D.

• New linear filtering functions: dip::SeparateFilter, dip::Dx, dip::Dy, dip::Dz, dip::Dxx, dip::Dyy, dip::Dzz, dip::Dxy, dip::Dxz, dip::Dyz, dip::Gradient, dip::GradientDirection, dip::Curl, dip::Divergence, dip::Hessian, dip::UnsharpMask, dip::GaborFIR, dip::Gabor2D, dip::LogGaborFilterBank, dip::NormalizedConvolution, dip::NormalizedDifferentialConvolution, dip::MeanShiftVector.

• New morphological functions: dip::RankFilter, dip::RankMinClosing, dip::RankMaxOpening, dip::LimitedMorphologicalReconstruction, dip::HMaxima, dip::HMinima, dip::Leveling, dip::AreaClosing, dip::OpeningByReconstruction, dip::ClosingByReconstruction, dip::AlternatingSequentialFilter, dip::HitAndMiss.

• New nonlinear filtering functions: dip::MoveToLocalMinimum, dip::PeronaMalikDiffusion, dip::GaussianAnisotropicDiffusion, dip::RobustAnisotropicDiffusion, dip::CoherenceEnhancingDiffusion.

• New generation functions: dip::FillRadiusCoordinate, dip::CreateRadiusCoordinate, dip::FillRadiusSquareCoordinate, dip::CreateRadiusSquareCoordinate, dip::FillPhiCoordinate, dip::CreatePhiCoordinate, dip::FillThetaCoordinate, dip::CreateThetaCoordinate, dip::FillCoordinates, dip::CreateCoordinates, dip::ApplyWindow, dip::DrawPolygon2D, dip::DrawBandlimitedPoint, dip::DrawBandlimitedLine, dip::DrawBandlimitedBall, dip::DrawBandlimitedBox, dip::SaltPepperNoise, dip::FillColoredNoise, dip::ColoredNoise, dip::GaussianEdgeClip, dip::GaussianLineClip, dip::FillDelta, dip::CreateDelta, dip::CreateGauss, dip::CreateGabor, dip::FillPoissonPointProcess, dip::CreatePoissonPointProcess, dip::FillRandomGrid, dip::CreateRandomGrid.

• New geometric transformation functions: dip::RotationMatrix2D, dip::RotationMatrix3D, dip::AffineTransform, dip::WarpControlPoints, dip::LogPolarTransform2D, dip::Tile, dip::TileTensorElements, dip::Concatenate, dip::JoinChannels.

• New grey-value mapping functions: dip::Zero, dip::HistogramEqualization, dip::HistogramMatching.

• New histogram functions: dip::CumulativeHistogram, dip::Smooth, dip::Mean, dip::Covariance, dip::MarginalMedian, dip::Mode, dip::PearsonCorrelation, dip::Regression, dip::MutualInformation, dip::Entropy, dip::IsodataThreshold, dip::OtsuThreshold, dip::MinimumErrorThreshold, dip::GaussianMixtureModelThreshold, dip::TriangleThreshold, dip::BackgroundThreshold, dip::KMeansClustering, dip::MinimumVariancePartitioning, dip::EqualizationLookupTable, dip::MatchingLookupTable, dip::PerObjectHistogram.

• New labeled regions function: dip::Relabel, dip::RegionAdjacencyGraph.

• New math and statistics functions: dip::IsNotANumber, dip::IsInfinite, dip::IsFinite, dip::InRange, dip::OutOfRange, dip::MaximumAbsoluteError, dip::PSNR, dip::SSIM, dip::MutualInformation, dip::SpatialOverlap, dip::DiceCoefficient, dip::JaccardIndex, dip::Specificity, dip::Sensitivity, dip::Accuracy, dip::Precision, dip::HausdorffDistance, dip::ModifiedHausdorffDistance, dip::SumOfMinimalDistances, dip::ComplementWeightedSumOfMinimalDistances, dip::Entropy, dip::EstimateNoiseVariance, dip::GeometricMean, dip::MeanSquare, dip::SumSquare, dip::MaximumAbs, dip::MinimumAbs, dip::MedianAbsoluteDeviation, dip::All, dip::Any, dip::Count, dip::CumulativeSum, dip::SampleStatistics, dip::Covariance, dip::PearsonCorrelation, dip::SpearmanRankCorrelation, dip::CenterOfMass, dip::Moments, dip::Transpose, dip::ConjugateTranspose, dip::DotProduct, dip::CrossProduct, dip::Norm, dip::SquareNorm, dip::Angle, dip::Orientation, dip::CartesianToPolar, dip::PolarToCartesian, dip::Determinant, dip::Trace, dip::Rank, dip::Eigenvalues, dip::LargestEigenvalue, dip::SmallestEigenvalue, dip::EigenDecomposition, dip::LargestEigenvector, dip::SmallestEigenvector, dip::Inverse, dip::PseudoInverse, dip::SingularValues, dip::SingularValueDecomposition, dip::Identity, dip::SumTensorElements, dip::ProductTensorElements, dip::AllTensorElements, dip::AnyTensorElement, dip::MaximumTensorElement, dip::MaximumAbsTensorElement, dip::MinimumTensorElement, dip::MinimumAbsTensorElement, dip::MeanTensorElement, dip::GeometricMeanTensorElement, dip::SortTensorElements, dip::SortTensorElementsByMagnitude, dip::Hypot.

• New measurement functions: see the class dip::Measurement, and functions that apply to it: dip::Minimum, dip::Maximum, dip::Percentile, dip::Median, dip::Mean, dip::MaximumAndMinimum, dip::SampleStatistics. See the classes dip::ChainCode, dip::Polygon, dip::ConvexHull, dip::CovarianceMatrix.

• New microscopy functions: dip::BeerLambertMapping, dip::InverseBeerLambertMapping, dip::UnmixStains, dip::MixStains, dip::MandersOverlapCoefficient, dip::IntensityCorrelationQuotient, dip::MandersColocalizationCoefficients, dip::CostesColocalizationCoefficients, dip::CostesSignificanceTest.

• New segmentation functions: dip::CompactWatershed, dip::StochasticWatershed, dip::WatershedMinima, dip::WatershedMaxima, dip::MinimumVariancePartitioning, dip::OtsuThreshold, dip::MinimumErrorThreshold, dip::GaussianMixtureModelThreshold, dip::TriangleThreshold, dip::BackgroundThreshold, dip::VolumeThreshold, dip::MultipleThresholds, dip::Superpixels.

• New testing functions: dip::testing::PrintPixelValues, dip::testing::CompareImages. New class: dip::testing::Timer.

• New transform functions: dip::OptimalFourierTransformSize, dip::RieszTransform, dip::StationaryWaveletTransform.

• There is also a lot of new functionality in the library infrastructure, which we cannot all list here. See the library infrastructure documentation.