List of MATLAB sample scripts

dsa_3.m

A demonstration of digital subtraction angiography as an example for algebraic operations on images.

OpenDICOM_3.m

Opening a single DICOM file and saving it in another image file format.

ConvertColorImage_3.m

Reading a color JPG image and storing it as a grayscale image.

BetterConvertColorImage_3.m

Same as ConvertColorImage_3.m, but in more decent MATLAB programming style.

SNRExample_3.m

Determination of x-ray dose compared to the signal-to-noise ratio in a series of x-ray images.

LinearIntensityTransform_4.m

Simple linear intensity scaling from arbitrary depth to six bit.

ComposeColorImage_4.m

Composing a color image from three single black-and-white photographs.

LogExample_4.m:The logarithm of image gray values as an example of a non-linear intensity transform.

SigmoidIntensityTransform_4.m

An example of generalized non-linear intensity transfer functions.

Histogram_4.m

Computation of an image histogram with arbitrary bin width.

OptimizeContrast_4.m

Automated contrast optimization based on histogram operations.

SimpleLowPass_5.m

Convolution with a low-pass filter or blurring kernel in the spatial domain.

NumericalDifferentiation_5.m

Introduction of the concept of numerical differentiation in one dimension.

ForwardDifference_5.m

A simple differentiation kernel for partial derivatives of images.

Sobel_5.m

Computing the absolute value of the total differential using Sobel-kernels, which results in an edge image.

UnsharpMask_5.m

Linear combination of filtering kernels; in this case, unsharp masking is presented as an example.

MedianFiveTimesFive_5.m

The median filter as an example of a non-linear filter.

Sine_5.m

A simple demonstration of bandpass-filtering in the Fourier domain on a onedi-mensional function.

ChordSpectrum_5.m

Another demonstration of the Fourier transform - the computation of power spectra for a musical chord played on three instruments.

Rect_5.m

Reconstruction of a onedimensional rectangle function including a demonstration of the Gibbs phenomenon.

WallFourier_Y_LP_5.m

Directional band pass filtering in Fourier space on a 2D image.

MouseSpectrum_5.m

Power spectrum of a 2D image.

Simpleconvolution_5.m

A demonstration of the convolution operation of onedimensional functions.

FourierDiffRect_5.m

Differentiation of simple functions in Fourier space.

BetterFourierDiffRect_5.m

An improved version of FourierDiffRect_5.m.

MouseFourierLP_5.m

Blurring images in the Fourier domain.

MouseConvolve_5.m

Application of the convolution theorem to a 2D image.

ComputeMTF_5.m

A real-life example of measuring the resolution of a ? camera with a point source.

Hough_5.m

Computation of the Hough transform on a binary image.

DistanceMap_5.m

Demonstration of the distance transform on a binary image.

ROIExample_6.m

Evaluation of pixel intensities in a region-of-interest as a direct correlate of activity from a nuclear medicine tracer.

ROIExampleWithJPGs_6.m A variation of ROIExample_6.m demonstrating that image depth is indeed of importance in image processing.

Threshold_6.m

Segmentation by intensity thresholding.

RegionGrowing_FourConnected_6.m

A simple implementation of region growing.

RegionGrowing_WanderingStaticSeed_6.m

A simple demo of the problems connected to 3D region growing.

SimpleSnakeSeeds_6.m

An initial, naive implementation of an active contour algorithm.

BetterSnakeSeeds_6m:

A variation of SimpleSnakeSeeds_6.m featuring an additional, more sophisticated energy term.

BetterSnakeSeedsConstrained_6.m

Another improved version of

SimpleSnakeSeeds_6.m.

MorphologicalOps_6.m

Erosion of a binary shape.

Hausdorff_6.m

Computation of the Hausdorff-distance between two contours.

Dice_6.m

Computation of a Dice-coefficient for two binary regions.

StepOne_Hough_6.m,StepTwo_DilateHough_6.mas

well as StepThree_Threshold_6.mare used in BrachyCleanup_6.m as parts of a more complex segmentation example on a multi-exposure x-ray.

Preprocessing_6.m and BetterSnakeSeedsConstrainedTwo_6.m

are parts of another more complex segmentation example showing the influence of appropriate preprocessing on active contours.

Simple2DRotation_7.m

Naive implementation of image rotation in 2D.

NNInterpolation_7.m

Image rotation of a 2D image using a not-so naive version of nearest neighbor interpolation.

BiLinearInterpolation_7.m

An example of bilinear interpolation on a low-resolution image.

BinaryPCA_7.m

Application of the principal axis transform on a binary segmented shape.

Conesects_7.m

A geometrical example on 3D spatial transforms and reformatting – the computation of conic sections.

ReformattingSmall_7.m

3D spatial transforms and reformatting on a small volume dataset.

ReformattingBig_7.m

Same as ReformattingSmall_7.m on a bigger dataset.

ThreeDConvolutionSmall_7.m

With reformatting at hand, we can also demonstrate that convolution, for instance with an edge-detection filter, also works in 3D.

ThreeDConvolutionBig_7.m

Same as ThreeDConvolutionSmall_7.m with a high-resolution version of the volume.

Perspective_8.m

A simple projection example using homogeneous coordinates and a projection operator.

Raytracing_8.m

A simple orthogonal rendering example.

RaytracingRotated_8.m

Same as Raytracing_8.m with additional 3D spatial transforms applied to the volume dataset.

Splatting_8.m

An alternative rendering method based on a projection operator in homogeneous cooridnates.

BetterSplatting_8.m

A more sophisticated version of Splatting_8.m.

VolumeSplatting_8.m

Volume rendering using color encoding of voxel grey values.

DepthShading_8.m

A simple surface rendering technique where the distance of a surface voxel to the image plane is encoded.

SurfaceShading_8.m

Example of a more common surface rendering technique employing a simple shading model.

Triangulation_8.m

A simple implementation of the cuberille algorithm producing a STL-file from a segmented voxel volume dataset.

BetterShadingII_8.m

A script that demonstrates shading for surface rendering of voxel volumes.

CC2DRegistration_9.m

Demonstration of a merit function based on cross correlation for intramodal registration.

More2DRegistration_9.m

Same as CC2DRegistration_9.m, but for quasi-intramodal registration.

JointHistogram_9.m

Computation of a joint histogram for an image compared to a rotated copy of the same image.

MultimodalJointHistogram_9.m

Same as JointHistogram_9.m but with a multimodal pair of images showing the same subject.

PlotMutualInformation2D_9.m

Computation of the mutual information measure for mul-timodal images.

DTChamfermatch_9.m and PlotChamferMatch2D_9.m

An example of chamfer matching, a gradient based technique.

SimpleOptimization_9.m, spike.m and strangeSine.m

An illustrative example on the pitfalls of numerical optimization.

Optimize2D_9.m and MI2D.m

Examples on optimization for registration.

DirectLinearTransform_9.m

An example of camera calibration using the direct linear transform.

MarkerRegistration_9.m

Analytical solution to the point-to-point registration problem.

mirotate.m

Replacement for the imrotate function of MATLAB for Octave users.

radotra.m

Computes the Radon-transform of a given image.

systemMatrix.m

Computation of a system matrix for algebraic reconstruction.

pseudoinverse_10.m

Algebraic reconstruction using inversion of the system matrix.

kaczmarz_randomised.m

An implementation of Kacmarz algorithm.

iterative_10.m

Algebraic reconstruction using Kacmarz algorithm.

filt.m

A function that plots the single steps in a filtering operation.

two_low_pass_filters_10.m

An illustration of filt.m.

ramp.m

A ramp filter.

conefilter_10.m

Application of a conefilter after unfiltered backprojection.

noise_10.m

Illustration of filtering effects on image noise.

radotra360.m

360 degree version of radotra.m

fbp360.m

360 degree version of fbp.m

ring_artefact_10.m

Example of the origins of ring artifacts.

streak_artefact_10.m

Illustration of streak artifacts generated by high attenuation.

volrotate.m

Rotates a volume around the z-axis.

projection.m

Cone-beam projection using volrotate.m.

fdk_backprojection.m

Cone-beam backprojection using the method of Feldkamp. Notation, etc., from Kak & Slaney.

demo_fdk.m

The demo script loads a 3D phantom file, computes cone-beam projections and then applies fdk_backprojection.