# Functions — By Category

View Functions Alphabetically

## Contents

- Time Domain Wave Propagation in Fluid Media
- Time Domain Wave Propagation in Elastic Media
- Time Domain Heat Diffusion
- Reference Solutions
- Photoacoustic Image Reconstruction
- Geometry and Shape Creation
- Acoustic Absorption Coefficient Calculation and Conversion
- Grid and Matrix Utilities
- Filtering and Spectral Utilities
- Display and Visualisation
- Signal Creation and Processing
- HDF5 Utilities
- System Parameters and Utilities

## Time Domain Wave Propagation in Fluid Media

`kspaceFirstOrder1D` | 1D time-domain simulation of wave propagation
`kspaceFirstOrder2D` | 2D time-domain simulation of wave propagation
`kspaceFirstOrder3D` | 3D time-domain simulation of wave propagation
`kspaceFirstOrder3DC` | 3D time-domain simulation of wave propagation using C++ code
`kspaceFirstOrder3DG` | 3D time-domain simulation of wave propagation on a GPU using C++ CUDA code
`kspaceSecondOrder` | Fast time-domain simulation of wave propagation for homogeneous media

## Time Domain Wave Propagation in Elastic Media

`pstdElastic2D` | 2D time-domain simulation of elastic wave propagation
`pstdElastic3D` | 3D time-domain simulation of elastic wave propagation

## Time Domain Heat Diffusion

`bioheatExact` | Compute exact solution to Pennes' bioheat equation in homogeneous media
`kWaveDiffusion` | Time-domain simulation of heat diffusion and perfusion

## Reference Solutions

`focusedBowlONeil` | Compute O'Neil's solution for focused bowl transducer
`mendousse` | Compute Mendousse's solution for nonlinear wave propagation in viscous media

## Photoacoustic Image Reconstruction

`kspaceLineRecon` | 2D linear FFT reconstruction
`kspacePlaneRecon` | 3D planar FFT reconstruction

See also kspaceFirstOrder1D, kspaceFirstOrder2D, and kspaceFirstOrder3D for time-reversal image reconstruction

## Geometry and Shape Creation

`makeArc` | Create a binary map of an arc within a 2D grid
`makeBall` | Create a binary map of a filled ball within a 3D grid
`makeBowl` | Create a binary map of a bowl within a 3D grid
`makeCartCircle` | Create a 2D Cartesian circle or arc
`makeCartSphere` | Create a 3D Cartesian sphere
`makeCircle` | Create a binary map of a circle within a 2D grid
`makeDisc` | Create a binary map of a filled disc within a 2D grid
`makeLine` | Create a binary map of a straight line within a 2D grid
`makeMultiArc` | Create a binary map of multiple arcs within a 2D grid
`makeMultiBowl` | Create a binary map of multiple bowls within a 3D grid
`makeSphere` | Create a binary map of a sphere within a 3D grid
`makeSphericalSection` | Create a binary map of a sphere segment within a 3D grid

## Acoustic Absorption Coefficient Calculation and Conversion

`attenComp` | Attenuation compensation using time-variant filtering
`attenuationWater` | Calculate ultrasound attenuation in distilled water
`db2neper` | Convert decibels to nepers
`fitPowerLawParams` | Fit power law absorption parameters for highly absorbing media
`neper2db` | Convert nepers to decibels
`powerLawKramersKronig` | Calculate dispersion for power law absorption

## Grid and Matrix Utilities

`cart2grid` | Interpolate a set of Cartesian points onto a binary grid
`expandMatrix` | Enlarge a matrix by extending the edge values
`findClosest` | Return the closest value in a matrix
`getSpacedPoints` | Create vector of log or linear spaced points
`grid2cart` | Return the Cartesian coordinates of the non-zero points of a binary grid
`interpCartData` | Interpolate data from a Cartesian to a binary sensor mask
`interpftn` | Resample data using Fourier interpolation
`kWaveGrid` | Class definition for k-Wave grid
`loadImage` | Load an image file
`maxND` | Return the value and indices of the largest value in an N-D array
`minND` | Return the value and indices of the smallest value in an N-D array
`numDim` | Return the number of matrix dimensions
`resize` | Resize a matrix
`reorderSensorData` | Reorder sensor data from kspaceFirstOrder2D based on angle
`revolve2D` | Form 3D matrix from revolution of 2D matrix
`fourierShift` | Resample data using a Fourier interpolant
`unmaskSensorData` | Reorder data recorded using a binary sensor mask

## Filtering and Spectral Utilities

`applyFilter` | Filter input with low, high, or band pass filter
`envelopeDetection` | Extract signal envelope using the Hilbert Transform
`filterTimeSeries` | Filter signal using the Kaiser windowing method
`gaussianFilter` | Filter signals using a frequency domain Gaussian filter
`getAlphaFilter` | Create filter for `medium.alpha_filter`
`getBLI` | Compute underlying Fourier band-limited interpolant (BLI)
`getFDMatrix` | Create a matrix of finite-difference coefficients
`getWin` | Return a frequency domain windowing function
`gradientFD` | Calculate the gradient using a finite-difference method
`gradientSpect` | Calculate the gradient using a Fourier spectral method
`sharpness` | Calculate image sharpness metric
`spect` | Compute the single sided amplitude and phase spectrums
`smooth` | Smooth a matrix
`vesselFilter` | Frangi's 3D vessel filter

## Display and Visualisation

`beamPlot` | Plot volumetric data using intersecting planes
`flyThrough` | Display a three-dimensional matrix slice by slice
`getColorMap` | Return default k-Wave color map
`overlayPlot` | Overlay two images
`saveTiffStack` | Save volume data as a tiff stack
`scaleFig` | Resize current figure window
`stackedPlot` | Stacked linear plot
`voxelPlot` | 3D plot of voxels in a binary matrix

## Signal Creation and Processing

`addNoise` | Add Gaussian noise to a signal for a given SNR
`createCWSignals` | Generate array of CW signals from amplitude and phase
`envelopeDetection` | Extract signal envelope using the Hilbert Transform
`extractAmpPhase` | Extract amplitude and phase from CW signals
`focus` | Create input signal based on source mask and focus position
`fwhm` | Compute the full width at half maximum
`gaussian` | Create a Gaussian distribution
`gaussianFilter` | Filter signals using a frequency domain Gaussian filter
`hounsfield2density` | Convert Hounsfield units to density
`kWaveTransducer` | Class definition for k-Wave linear array transducer
`logCompression` | Log compress an input signal
`scanConversion` | Convert scan-lines in polar coordinates to a B-mode ultrasound image
`toneBurst` | Create an enveloped single frequency tone burst

## HDF5 Utilities

`h5compare` | Compare the contents of two HDF5 files
`writeAttributes` | Write attributes to a k-Wave HDF5 file
`writeFlags` | Write input flags to a k-Wave HDF5 file
`writeGrid` | Write grid and PML properties to a k-Wave HDF5 file
`writeMatrix` | Write MATLAB matrix to a k-Wave HDF5 file

## System Parameters and Utilities

`benchmark` | Run performance benchmark
`checkFactors` | Return the maximum prime factor for a range of numbers
`checkStability` | Return maximum stable time step for k-space fluid models
`getDateString` | Create a string of the current date and time
`getComputerInfo` | Return information about computer and k-Wave version
`getkWavePath` | Return pathname to the k-Wave Toolbox
`scaleSI` | Scale a number to nearest SI unit prefix
`scaleTime` | Convert seconds to hours, minutes, and seconds
`speedSoundWater` | Calculate the speed of sound in water with temperature