DownValues[f] gives a list of transformation rules corresponding to all downvalues defined for the symbol f.
Element
(Built-in Mathematica Symbol) Element[x, dom] or x \[Element] dom asserts that x is an element of the domain dom. Element[{x_1, x_2, ...}, dom] asserts that all the x_i are elements of dom. Element[patt, ...
Exponent[expr, form] gives the maximum power with which form appears in the expanded form of expr. Exponent[expr, form, h] applies h to the set of exponents with which form ...
ExportString[expr, " format"] generates a string corresponding to expr exported in the specified format. ExportString[rules, {"format", "Rules"}] gives explicit rules for ...
GaussianFilter[image, r] filters image by convolving with a Gaussian kernel of pixel radius r.GaussianFilter[image, r, {n_1, n_2}] convolves image with a kernel formed from ...
GradientFilter[image, r] gives an image corresponding to the magnitude of the gradient of image, computed using discrete derivatives of a Gaussian of pixel radius ...
Hash
(Built-in Mathematica Symbol) Hash[expr] gives an integer hash code for the expression expr.Hash[expr, " type"] gives an integer hash code of the specified type for expr.
ImageCorrespondingPoints[image_1, image_2] finds a set of matching interest points in image_1 and image_2 and returns their pixel coordinates.
ImageDeconvolve[image, ker] gives a deconvolution of image using kernel ker.
ImageFilter[f, image, r] applies the function f to the range r neighborhood of each pixel in each channel of image.