The Octave-forge Image package provides functions for processing images. The package also provides functions for feature extraction, image statistics, spatial and geometric transformations, morphological operations, linear filtering, and much more.

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Compute correlation coefficients of images.

Find edges using various methods.

Convolve 2 dimensional signals using the FFT.

Convolve N dimensional signals using the FFT for computation.

Compute the mean value of the 2D image I.

Returns the standard deviation for a 2d real type matrix.

Computes the entropy of an image.

Computes the local entropy in a neighbourhood around each pixel in an image.

Performs quadtree decomposition.

Obtain block values from a quadtree decomposition.

Set block values in a quadtree decomposition.

Calculates the gray-level co-occurrence matrix P of a gray-level image IM.

Perform the Hough transform for lines or circles.

Calculate the straight line Hough transform of a binary image I.

Perform the Hough transform for circles with radius R on the black-and-white image BW.

Compute the gradient magnitude and direction in degrees for an image.

Compute the x and y gradients of an image using various methods.

Produce histogram counts of image I.

Find local spatial maximas.

Compute mean squared error.

Compute normalized cross-correlation.

Compute peak signal-to-noise ratio.

Computes the local intensity range in a neighbourhood around each pixel in an image.

Compute properties of image regions.

Computes the local standard deviation in a neighbourhood around each pixel in an image.

Return absolute difference of image or constant to an image.

Add image or constant to an image.

Compute image complement or negative.

Divide image by another image or constant.

Combine images linearly.

Multiply image by another image or constant.

Subtract image or constant to an image.

Uses lookup tables to perform a neighbour operation on binary images.

Estimate total area of objects on the image BW.

Filter objects from image based on their sizes.

Trace the boundaries of the objects in a binary image.

Find connected objects.

Compute distance transform in binary image.

Calculate the Euler number of a binary image.

Perform a flood-fill operation on the binary image BW1.

Perform binary hit-or-miss transform.

Label binary 2 dimensional image.

Label foreground objects in the n-dimensional binary image BW.

Perform morphological operation on binary image.

Find perimeter of objects in binary images.

Filter objects from image based on their properties.

Select connected regions in a binary image.

Determine the Freeman chain code for a boundary.

Create labelled matrix from bwconncomp structure.

Create a lookup table which can be used by applylut.

Define a colour map which smoothly traverses the given colors.

Convert RGB values to YCbCr.

Convert wavelength in nm into an RGB value set.

Convert YCbCr color space to RGB.

Create montage from multiple images.

Display images in subplots.

Equalize histogram of grayscale image.

Adjust image or colormap intensity (values).

Add noise to image.

Smooth the given image using several different algorithms.

Two dimensional median filtering.

Two dimensional ordered filtering.

N dimensional ordered filtering.

Find limits to contrast stretch an image.

Estimate bounds for spatial transformation.

Create spatial filters for image processing.

Computes the linear filtering of the image I and the filter F.

Transform image.

Convert integer values with lookup table (LUT).

Performs filtered back-projection on the projections in PROJ to reconstruct an approximation of the original image.

Performs non-maximum supression on the given edge data.

Calculates the 2D-Radon transform of the matrix I at angles given in THETA.

Filters the parallel ray projections in the columns of PROJ, according to the filter type chosen by TYPE.

Perform area opening.

Create connectivity array.

Perform morphological bottom hat filtering.

Clear borders of objects or ligher structures.

Perform morphological closing.

Perform morphological dilation.

Perform morphological erosion.

Fill image holes or regions.

Perform morphological opening.

See also: imclearborder, imdilate, imerode.

Compute regional maxima.

Compute regional minima.

Perform morphological top hat filtering.

Perform morphological gradient.

Return the heights of a non-flat structuring element.

Get neighbors relative position and height.

Return the neighborhood of structuring element SE.

Decompose structuring element.

Say if a structuring element object is flat or not.

Reflect structuring element of strel object.

Create a strel (structuring element) object for morphology operations.

Generate a new structuring element, which is SE translated in rows and columns as expressed in the offset 2-dimensional array V.

Compute watershed transform.

Read header of an Analyze 7.5 file.

Read image data of an Analyze 7.5 file.

Write image data to an Analyze 7.5 file.

Read value of TAGs from TIFF files.

Calculate block best size for block processing.

Processes image in blocks using user-supplied function.

Rearrange block columns back into matrix.

Apply function to matrix blocks

Rearrange blocks from matrix into columns.

Get pixel values.

Process matrix in sliding blocks with user-supplied function.

Convert a polygon to a region mask.

Select a Region Of Interest of an image based on color.

Return a transformation structure T (see "help maketform" for the form of the structure) that can be further used to transform coordinates between an input space and an ouput space.

Crop image.

Applies the spatial perspective homogeneous transformation P to the image IM.

Compute gaussian pyramid expansion or reduction.

Applies any geometric transformation to the image IM.

Resize image with interpolation

Rotate image about its center.

Applies a shear to the image M.

Translate a 2D image by (x,y) using Fourier interpolation.

Create a transform structure T to be used for spatial transformations between an input space and an output space.

Arbitrary rotation and scaling of a gray-scale image using fast bilinear interpolation.

Given a transform structure T, transform coordinates UV in the input space into coordinates XY in the output space.

Given a transform structure T, transform coordinates XY in the output space into coordinates UV in the input space.

Create indexed image from intensity image using multilevel thresholding.

Compute global image threshold.

Convert image to binary, black and white, by threshold.

Convert image to double precision.

Convert image to int16.

Convert image to single precision.

Convert image to uint8.

Convert image to uint16.

Convert image to specific data type TYPE.

Reduce the number a colors of rgb or indexed image.

Quantize image with multiple threshold levels and values.

Return true if IMG is a black and white image.

Return true if IMG is a grayscale image.

Return true if IMG is an indexed image.

Return true if IMG is a RGB image.

Convert L*a*b* data to double precision.

Transform a colormap or image from CIE L*a*b* to sRGB color space.

Convert L*a*b* data to single precision.

Convert L*a*b* data to uint16 precision.

Convert L*a*b* data to uint8 precision.

Transform a colormap or image from CIE L*a*b* to CIE XYZ color space.

Convert labeled image into RGB.

Convert a matrix to an intensity image.

Convert RGB image or colormap to grayscale.

Transform a colormap or image from sRGB to CIE L*a*b* color space.

Transform a colormap or image from sRGB to CIE XYZ color space.

Transform a colormap or image from CIE XYZ to CIE L*a*b* color space.

Transform a colormap or image from CIE XYZ to sRGB color space.

Create checkerboard.

Blur border (edges) of image to prevent ringing artifacts.

Return display range of image.

Get information about image attributes.

Open GUI dialogue to select image files.

Check if argument is valid connectivity.

Check if argument is valid colormap.

Convert number to ordinal string.

Compute PSF from OTF.

Pad array or matrix.

Create computational phantom head.

Compute OTF from PSF.

Package: image