Function 
Description 
Geometric Transformations 
pixeldup 
Duplicates pixels of an image in both directions. 
vistformfwd 
Used to visualize forward geometric transformations. 
Pixel Values and Statistics 
covmatrix 
Computes the covariance matrix of a vector population. 
statmoments 
Computes statistical central moments of an image histogram. 
Image Analysis (Includes Segmentation, Description, and Recognition) 
bayesgauss 
Bayes classifier for Gaussian patterns. 
bound2eight 
Converts a 4connected boundary to an 8connected boundary. 
bound2four 
Converts an 8connected boundary to a 4connected boundary. 
bound2im 
Converts a boundary to an image. 
boundaries 
Traces region boundaries. 
bsubsamp 
Subsamples a boundary. 
colorgrad 
Computes the vector gradient of an RGB image. 
colorseg 
Segments a color image. 
connectpoly 
Connects
vertices of a polygon. 
diameter 
Measures the diameter of image regions. 
endpoints 
Compute end points of a binary image. 
fchcode 
Computes the Freeman chain code of a boundary. 
frdescp 
Computes Fourier descriptors. (See also
ifrdescp.) 
hough 
Hough transform. 
houghlines 
Extracts line segments based on the Hough transform. 
houghpeaks 
Detects peaks in the Hough transform. 
houghpixels 
Computes image pixels belonging to Hough transform bin. 
ifrdescp 
Computes inverse Fourier descriptors. 
imstack2vectors 
Extracts vectors from an image stack. 
invmoments 
Computes invariant moments of an image. 
mahalanobis 
Computes the Mahalanobis distance. 
minperpoly 
Computes minimum perimeter polygons. 
polyangles 
Computes internal polygon angles. 
princomp 
Obtains principalcomponent vectors and related quantities. 
randvertex 
Randomly displaces polygon vertices. 
regiongrow 
Performs segmentation by region growing. 
signature 
Computes the signature of a boundary. 
specxture 
Computes spectral texture of an image. 
splitmerge 
Segments an image using a splitandmerge algorithm.

statxture 
Computes statistical measures of texture in an image. 
strsimilarity 
Computes a similarity measure between two strings.

x2majoraxis 
Aligns coordinate axis x with the major axis of a region.

Image Compression 
compare 
Computes and displays the error between two matrices.

entropy 
Computes a firstorder estimate of the entropy of a matrix. 
huff2mat 
Decodes a Huffman encoded matrix. 
huffman 
Builds a variablelength Huffman code for symbol source. 
im2jpeg 
Compresses an image using a JPEG approximation. 
im2jpeg2k 
Compresses an image using a JPEG 2000 approximation. 
imratio 
Computes the ratio of the bytes in two images/variables.

jpeg2im 
Decodes an IM2JPEG compressed image. 
jpeg2k2im 
Decodes an IM2JPEG2K compressed image. 
lpc2mat 
Decompress a 1D lossless predictive encoded matrix.

mat2huff 
Huffman encodes a matrix. 
mat2lpc 
Compresses a matrix using 1D lossless predictive coding. 
quantize 
Quantizes the elements of an UINT8 matrix. 
Image Enhancement 
gscale 
Scales the intensity values of an image. 
intrans 
Performs intensity transformations. 
Image Noise 
imnoise2 
Generates an array of random numbers with a specified PDF. 
imnoise3 
Generates periodic noise. 
Linear and Nonlinear Spatial Filtering 
adpmedian 
Performs adaptive median filtering 
dftcorr 
Performs frequency domain correlation. 
dftfilt 
Performs frequency domain filtering. 
spfilt 
Performs linear and nonlinear spatial filtering. 
Linear 2D Filter Design 
hpfilter 
Computes frequency domain highpass filters. 
lpfilter 
Computes frequency domain lowpass filters. 
Wavelets 
wave2gray 
Displays wavelet decomposition coefficients. 
waveback 
Performs a multilevel, 2dimensional inverse FWT. 
wavecopy 
Fetches coefficients of a wavelet decomposition structure.

wavecut 
Sets to zero coefficients in a wavelet decomposition structure. 
wavefast 
Performs a multilevel 2dimensional fast wavelet transform. 
wavefilter 
Creates wavelet decomposition and reconstruction filters. 
wavepaste 
Puts coefficients in a wavelet decomposition structure.

wavework 
Edits wavelet decomposition structures. 
wavezero 
Sets wavelet detail coefficients to zero. 
RegionBased Processing 
histroi 
Computes the histogram of an ROI in an image. 
Color Image Processing 
hsi2rgb 
Converts HSI values to RGB color space. 
ice 
Performs interactive color editing. 
rgb2hsi 
Converts RGB values to HSI color space. 
rgbcube 
Displays a color RGB cube. 
Array Operations 
dftuv 
Computes meshgrid arrays. 
paddedsize 
Computes the minimum required pad size for use in FFTs.

Miscellaneous 
changeclass 
Changes the class of an image. 
conwaylaws 
Applies Conways genetic laws to a single pixel.

intline 
Integercoordinate line drawing algorithm. 
manualhist 
Generates a bimodal histogram interactively. 
twomodegauss 
Generates a bimodal Gaussian function. 

