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Image Processing

Contrast Enhancement and Filtering

ADAPT_HIST_EQUAL - Performs adaptive histogram equalization

BYTSCL - Scales all values of an array into range of bytes.

CONVOL - Convolves two vectors or arrays.

DIGITAL_FILTER - Calculates coefficients of a non-recursive, digital filter.

FFT - Returns the Fast Fourier Transform of an array.

HILBERT - Constructs a Hilbert transform.

HIST_EQUAL - Histogram-equalizes an image.

LEEFILT - Performs the Lee filter algorithm on an image array.

MEDIAN - Returns the median value of Array or applies a median filter.

ROBERTS - Returns an approximation of Roberts edge enhancement.

SMOOTH - Smooths with a boxcar average.

SOBEL - Returns an approximation of Sobel edge enhancement.

UNSHARP_MASK - Performs an unsharp-mask sharpening filter on a two-dimensional array or a truecolor image.

See Also - Wavelet Toolkit

Feature Extraction/Image Segmentation

CONTOUR - Draws a contour plot.

DEFROI - Defines an irregular region of interest of an image.

HISTOGRAM - Computes the density function of an array.

HOUGH - Returns the Hough transform of a two-dimensional image.

IMAGE_STATISTICS - Computes sample statistics for a given array of values.

ISOCONTOUR - Interprets the contouring algorithm found in the IDLgrContour object.

ISOSURFACE - Returns topologically consistent triangles by using oriented tetrahedral decomposition.

LABEL_REGION - Labels regions (blobs) of a bi-level image.

MAX - Returns the value of the largest element of Array.

MEDIAN - Returns the median value of Array or applies a median filter.

MIN - Returns the value of the smallest element of an array.

PROFILES - Interactively examines image profiles.

RADON - Returns the Radon transform of a two-dimensional image.

REGION_GROW - Perform region growing.

SEARCH2D - Finds "objects" or regions of similar data within a 2D array.

THIN - Returns the "skeleton" of a bi-level image.

UNIQ - Returns subscripts of the unique elements in an array.

WATERSHED - Applies the morphological watershed operator to a grayscale image.

WHERE - Returns subscripts of nonzero array elements.

Image Display

DISSOLVE - Provides a digital "dissolve" effect for images.

IDLgrImage - Creates an image object that represents a mapping from a 2D array of data values to a 2D array of pixel colors.

IDLgrPalette - Represents a color lookup table that maps indices to red, green, and blue values.

IIMAGE - Creates an iTool and associated user interface (UI) configured to display and manipulate image data.

RDPIX - Interactively displays image pixel values.

SLIDE_IMAGE - Creates a scrolling graphics window for examining large images.

TV - Displays an image. To scale and display the image, use TVSCL.

TVCRS - Manipulates the image display cursor.

TVLCT - Loads display color tables.

TVSCL - Scales and displays an image.

XOBJVIEW - Displays object viewer widget.

XOBJVIEW_ROTATE - Programmatically rotate the object currently displayed in XOBJVIEW.

XOBJVIEW_WRITE_IMAGE - Write the object currently displayed in XOBJVIEW to an image file.

ZOOM - Zooms portions of the display.

ZOOM_24 - Zooms portions of true-color (24-bit) display.

Image Geometry Transformations

CONGRID - Resamples an image to any dimensions.

EXPAND - Shrinks/expands image using bilinear interpolation.

EXTRAC - Returns sub-matrix of input array. Array operators (e.g., * and :) should usually be used instead.

INTERPOLATE - Returns an array of interpolates.

INVERT - Computes the inverse of a square array.

POLY_2D - Performs polynomial warping of images.

POLYWARP - Performs polynomial spatial warping.

REBIN - Resizes a vector or array by integer multiples.

REFORM - Changes array dimensions without changing the total number of elements.

REVERSE - Reverses the order of one dimension of an array.

ROT - Rotates an image by any amount.

ROTATE - Rotates/transposes an array in multiples of 90 degrees.

SHIFT - Shifts elements of vectors or arrays by a specified number of elements.

TRANSPOSE - Transposes an array.

WARP_TRI - Warps an image using control points.

Morphological Image Operators

DILATE - Implements morphologic dilation operator on binary and grayscale images.

ERODE - Implements the erosion operator on binary and grayscale images and vectors.

LABEL_REGION - Labels regions (blobs) of a bi-level image.

MORPH_CLOSE - Applies closing operator to binary or grayscale image.

MORPH_DISTANCE - Estimates N-dimensional distance maps, which contain for each foreground pixel the distance to the nearest background pixel, using a given norm.

MORPH_GRADIENT - Applies the morphological gradient operator to a grayscale image.

MORPH_HITORMISS - Applies the hit-or-miss operator to a binary image.

MORPH_OPEN - Applies the opening operator to a binary or grayscale image.

MORPH_THIN - Performs a thinning operation on binary images.

MORPH_TOPHAT - Applies top-hat operator to a grayscale image.

WATERSHED - Applies the morphological watershed operator to a grayscale image.

Regions of Interest

CW_DEFROI - Creates compound widget used to define region of interest.

DEFROI - Defines an irregular region of interest of an image.

DRAW_ROI - Draws region or group of regions to current Direct Graphics device.

IDLanROI - Represents a region of interest used for analysis.

IDLanROIGroup - Analytical representation of a group of regions of interest.

IDLgrROI - Object graphics representation of a region of interest.

IDLgrROIGroup - Object Graphics representation of a group of regions of interest.

LABEL_REGION - Labels regions (blobs) of a bi-level image.

REGION_GROW - Grows an initial region to include all areas that match specified constraints.

XROI - Utility for defining regions of interest, and obtaining geometry and statistical data about these ROIs.

  IDL Online Help (June 16, 2005)