Some simple algorithms for manipulating images. Note that the argument order is typically of the form vil_f(src_im,dest_im,params). Examples include

- vil_convolve_1d - Convolve with 1D filter - all manner of edge effects catered for
- vil_convolve_2d - Convolve with 2D filter (no edge effects catered for yet!)
- vil_correlate_1d - Similar to vil_convolve_1d but with reversing the kernel
- vil_correlate_2d - Similar to vil_convolve_2d but with reversing the kernel
- vil_gauss_filter_gen_ntap - Generate an n-tap FIR filter from a Gaussian function
- vil_gauss_filter_5tap - Apply 1d Gaussian filter using 5 element kernel
- vil_gauss_filter_1d - Apply 1d Gaussian filter of arbitrary SD and kernel width
- vil_gauss_filter_2d - Apply 2d Gaussian filter of arbitrary SD and kernel width
- vil_exp_filter_i - Apply exponential filter along i axis (fast recursive method)
- vil_exp_filter_j - Apply exponential filter along j axis (fast recursive method)
- vil_exp_filter_2d - Apply exponential filter along i and j (fast recursive method)
- vil_exp_grad_filter_i - Apply exponential gradient filter along i axis (fast recursive method)
- vil_exp_grad_filter_j - Apply exponential gradient filter along j axis (fast recursive method)
- vil_sobel_3x3 - to generate X/Y gradient images using 3x3 Sobel operators
- vil_gauss_reduce - smooth and sub-sample to produce half sized image
- vil_median - Compute median over area described by vil_structuring_element
- vil_fft_2d_fwd,bwd - Perform in-place 2D FFT on an image of a complex type
- vil_suppress_non_max_3x3 - Zero all pixels which are not local maxima
- vil_corners - Harris cornerness operator
- vil_find_peaks - Locate local peaks in an image
- vil_orientations - Compute angle and edge magnitude at each pixel
- vil_distance_transform - Apply distance transform to images
- vil_histogram_equalise - Replace every pixel by its intensity rank
- vil_suppress_non_max_edges - Compute gradient magnitude and zero any non-maximal values

See also the vipl library for a more generic image processing interface and more image processing algorithms.

Morphological functions (using vil_structuring_element)

- vil_binary_erode
- vil_binary_dilate
- vil_binary_opening
- vil_binary_closing
- vil_greyscale_erode
- vil_greyscale_dilate
- vil_greyscale_opening
- vil_greyscale_closing
- vil_median

Other related maths functions

- vil_histogram(image,hist,min,max,nbins) : Compute histogram of image values
- vil_histogram_byte(image,histo) : Compute histogram from byte image

The boundaries of thresholded regions can be found using

- vil_find_4con_boundary_above_threshold
- vil_find_4con_boundary_below_threshold (Given a point inside a closed, 4-connected region defined by a threshold, these functions find the 4-connected boundary pixels of the region)

- vil_trace_4con_boundary : Traces around 4 connected regions in bool image
- vil_trace_8con_boundary : Traces around 8 connected regions in bool image
- vil_blob_finder : Class to find all connected regions in an image

- vil_tile_images : Generate single image by tiling together a set of images

For your ease of use, all vil functions and methods adhere to the following parameter conventions:

- Index types - All pixel index and image size types are unsigned.
- Specifying a pixel - func(i,j) assumes plane 0 or func(i,j,p)
- Specifying a window - func(i0,ni,j0,nj) window includes all planes.

Generated on Sun Nov 22 06:18:52 2009 for core/vil by 1.5.5