imFilters

The imFilters packages contains various functions for filtering and transforming images. Functions may operate on grayscale, color, label images, and on 2D or 3D images.

Image enhancement, noise removal

imAdjustDynamic          - Rescale gray levels of image to get better dynamic
imMeanFilter             - Compute mean value in the neighboorhood of each pixel
imMedianFilter           - Compute median value in the neighboorhood of each pixel
imGaussianFilter         - Apply gaussian filter to an image, using separability
imDirectionalFilter      - Apply and combine several directional filters
imNormalizeBackground    - Normalize image by removing background estimate

Edge detection filters (Gradient, Laplacian...)

imGradient               - Compute gradient magnitude in a grayscale image
imLaplacian              - Discrete Laplacian of an image
imHessian                - Compute coefficients of Hessian matrix for each pixel
imEigenValues            - Image eigen values from second derivatives
imEigenValues3d          - Image eigen values from second derivatives
imVesselness2d           - Vesselness of cuvilinear structures from Frangi paper
imRobinsonFilter         - Extract image edges using Robinson directional filters
imKirschFilter           - Extract image edges using Kirsch directional filters

Morphological filters

imMorphoGradient         - Morphological gradient of an image
imMorphoLaplacian        - Morphological laplacian of an image
imrecerode               - Perform a morphological reconstruction by erosion
imHConcave               - H-concave transformation of an image
imHConvex                - H-convex transformation of an image

Geometric filters

imFlip                   - Flip an image along one of its dimensions
imRotate90               - Rotate a 3D image by 90 degrees around one image axis
imAddBorder              - Add a border around a 2D or 3D image
imTranspose              - Transpose an image (grayscale or RGB)
subsample                - Subsample an array by applying operation on blocs
subsamplergb             - Return a sub-sampled version of an rgb image.

Segmentation

imOtsuThreshold          - Threshold an image using Otsu method
imImposedWatershed       - Compute watershed after imposition of extended minima
imCannyEdgeDetector      - Edge detection using Canny-Deriche method

Color and gray-scale conversions

imOverlay                - Add colored markers to an image (2D or 3D, grayscale or color)
imSplitChannels          - Split the 3 channels of a 2D or 3D image
imMergeChannels          - Merge 3 channels to create a 2D or 3D color image
double2rgb               - Create a RGB image from double values
angle2rgb                - Convert an image of angles to color image
imGetHue                 - Extract hue of a color image, using rgb2hsv.
imGray12ToGray8          - Convert a 12 bits gray scale image to 8 bits gray scale

Filters for binary images

imBoundary               - Compute the boundary image of a binary image
imFillHoles              - Fill holes in a binary image
imDistanceMap            - Compute chamfer distance using scanning algorithm
imDistanceClasses        - Converts a distance map to a label image of regions
imSkeleton               - Homothopic skeleton of a binary image 
imLabelSkeleton          - Label skeleton pixels according to local topology
imChainPixels            - Chain neighbor pixels in an image to form a contour
imConvexImage            - Compute smallest convex image containing the original pixels
imDistance               - Distance map computed from a set of points
imDistance3d             - Create distance image from a set of 3D points

Filters for binary/label images

label2rgb3d              - Convert a 3D label image to a 3D RGB image
imKillBorders            - Remove regions on the border of an image
imAreaOpening            - Remove all regions smaller than a given area
imAttributeOpening       - Filter regions on a size or shape criterium
imLargestRegion          - Keep the largest region in a binary or label image
imCropLabel              - Extract the portion of image that contains the specified label
imMergeLabels            - Merge regions in a labeled image
mergeRegions             - Merge regions of labeled image, using inclusion criteria
imBoundaryIndices        - Find indices of boundary between 2 cells
imLabelEdges             - Label edges between adjacent regions of labeled image.

Utilities and drawing

imCreate                 - Create a new image with given the size and type
imCheckerBoard           - Create a checkerboard image from 2 images
imCheckerboardLabels     - Create a checkerboard label image
imThumbnail              - Resize an image to bound the size in each direction
imDrawLine               - Draw a line between two points in the image
bresenhamLine            - Integer coordinates of a bresenham line
imDrawText               - Draw some text in an image
imTpsWarp                - Warp an image using Thin-Plate Splines transform

Indexed images

imLUT                    - Apply a look-up table (LUT) to a gray-scale image.
grayFilter               - Compute configuration map of a binary image
grayHist                 - Compute frequencies of configurations in binary images
createTile               - Create a binary tile (2x2) from its index
tileIndex                - Return the index of a 2x2 binary tile
createTile3d             - Create a 3D binary tile (2x2x2) from its index
tileIndex3d              - Return the index of a 2x2x2 binary tile

Kernels and structuring elements

ball                     - Generate a ball in a matrix in 2 or 3 dimensions
gaussianKernel3d         - Create a 3D Gaussian kernel for image filtering
orientedGaussianKernel   - Oriented Gaussian kernel for directional filtering
orientedLaplacianKernel  - Oriented Laplacian kernel for directional filtering
cross3d                  - Return a 3D structuring element with cross shape
intline                  - Integer-coordinate line drawing algorithm.
strelDisk                - Discrete disk structuring element
imNeighborhood           - Return the neighborhood of a given pixel