angle - gradient direction of edges
bwborder - border detection for binary images
bwdist - distance transforms
curvature2d - curvature of a surface or image
curvature - curvature of a contour
dilate - morphological dilation of binary images
drawline - draws line in a binary image 
edge - edge detection
edilate - euclidean morphological dilation of binary images
erode - morphological erosion of binary images
fftderiv - derivative of a vector using FFT
follow - a contour follower
fractal - multiscale fractal dimension curve
gray_imread - read any image as grayscale
gsm2d - 2D gaussian smoothing
gsm - 1D gaussian smoothing
hello_sip - learn to add your own C routine to SIP
hough - hough transform for line detection
ihough - inverse hough transform 
im2bw - convert images to binary by thresholding
im2gray - converts color images or colormaps to grayscale
imconv - 2D convolution
imcorrcoef - template matching by normalized correlation
imfinfo - image file information
imnoise - generate noise (salt & pepper, etc)
imphase - image phase calculation.
improfile - draws intensity profiles of an image
imread - reads image file in ANY format
imroi - roi (region of interest) of an image
imshow - displays images in scilab graphic window
imvariance - calculates the variance of an image
imwrite - writes to an image file in ANY format
minmax - Min/Max algorithm for noise removal from images
mkfilter - returns popular 2D convolution kernels
mogrify - filtering, histogram equalization, rotating, zooming, etc
normal - normalize array to a given range
ntsc2rgb - converts from YIQ to RGB colorspace
percol - test if binary image is percolated 
perim - perimeter of binary shape
pifilter - pi filter for phased images
rgb2ntsc - converts from RGB to YIQ colorspace
sip_fftshift - swap arrays (used with fft)
skel - skeletonization, thinning, Medial Axis Transform
thin - thinning by border deletion
unfollow - converts a parametric contour into a binary image
unwrapl - unwraps phased images linearly
unwrapp - unwraps phased images by path following
watershed - image segmentation with markers
xgetpixel - gets the pixel coordinates from an image
xor - exclusive or
