Image Pyramids
[Image Package]

Classes
struct	Gan_ImagePyramid
	Structure to hold image and mask at a single pyramid level. More...
Typedefs
typedef Gan_ImagePyramid	Gan_ImagePyramid
	Structure to hold image and mask at a single pyramid level.
typedef enum Gan_ImagePyramidAverage	Gan_ImagePyramidAverage
	Type of averaging used when combining four pixels into one.
Enumerations
enum	Gan_ImagePyramidAverage { GAN_AVERAGE_ALL, GAN_AVERAGE_IN_MASK }
	Type of averaging used when combining four pixels into one. More...
Functions
Gan_Image *	gan_image_halve_size (Gan_Image *image, Gan_Image *himage)
	Halve the size of an image.
Gan_Bool	gan_image_pyramid_build_preallocated (Gan_Image *img, Gan_Image *mask, unsigned no_levels, Gan_ImagePyramidAverage average_type, unsigned no_neighbours, Gan_Image **imgarray, Gan_Image **maskarray, Gan_ImagePyramid **pyramid)
	Builds an image pyramid.using preallocated image buffers passed in.
void	gan_image_pyramid_free (Gan_ImagePyramid *pyramid, unsigned no_levels, Gan_Bool free_top_level)
	Frees an image pyramid.
Gan_Bool	gan_image_pyramid_build (Gan_Image *img, Gan_Image *mask, unsigned no_levels, Gan_ImagePyramidAverage average_type, unsigned no_neighbours, Gan_ImagePyramid **pyramid)
	Macro: Builds an image pyramid.

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Enumeration Type Documentation

enum Gan_ImagePyramidAverage

Type of averaging used when combining four pixels into one. Enumeration values: GAN_AVERAGE_ALL  take average of all four pixels GAN_AVERAGE_IN_MASK  take average only of pixels in the mask

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Function Documentation

Gan_Image * gan_image_halve_size (  Gan_Image *  image, Gan_Image *  himage )

Halve the size of an image. Parameters: image  Input image himage  Output image or NULL Returns: Result image or NULL with error on failure.

Gan_Bool gan_image_pyramid_build (  Gan_Image *  img, Gan_Image *  mask, unsigned  no_levels, Gan_ImagePyramidAverage  average_type, unsigned  no_neighbours, Gan_ImagePyramid **  pyramid )

Macro: Builds an image pyramid. Parameters: img  The top-level image in the pyramid mask  The mask corresponding to the top-level image or NULL no_levels  The number of levels in the pyramid average_type  The type of averaging of four-pixel neighbourhoods no_neighbours  Minimum number of neighbours set to transfer resolution pyramid  Pointer to the pyramid Returns: GAN_TRUE on success, GAN_FALSE on failure. Builds an image pyramid. If the mask is NULL, the pyramid is built without masks, i.e. assuming that all the pixels are valid. no_neighbours is the least number of number of pixels in any four-pixel neighbourhood of mask pixels needed to be one in order for the lower resolution mask to be set to one. This is a macro call to gan_image_pyramid_build_preallocated(). See also: gan_image_pyramid_free().

Gan_Bool gan_image_pyramid_build_preallocated (  Gan_Image *  img, Gan_Image *  mask, unsigned  no_levels, Gan_ImagePyramidAverage  average_type, unsigned  no_neighbours, Gan_Image **  imgarray, Gan_Image **  maskarray, Gan_ImagePyramid **  pyramid )

Builds an image pyramid.using preallocated image buffers passed in. Parameters: img  The top-level image in the pyramid mask  The mask corresponding to the top-level image or NULL no_levels  The number of levels in the pyramid average_type  The type of averaging of four-pixel neighbourhoods no_neighbours  Minimum number of neighbours set to transfer resolution imgarray  Array of at least no_levels-1 preallocated image buffers or NULL maskarray  Array of at least no_levels-1 preallocated mask buffers or NULL pyramid  Pointer to the pyramid Returns: GAN_TRUE on success, GAN_FALSE on failure. Builds an image pyramid. If the mask is NULL, the pyramid is built without masks, i.e. assuming that all the pixels are valid. no_neighbours is the least number of number of pixels in any four-pixel neighbourhood of mask pixels needed to be one in order for the lower resolution mask to be set to one. See also: gan_image_pyramid_free().

void gan_image_pyramid_free (  Gan_ImagePyramid *  pyramid, unsigned  no_levels, Gan_Bool  free_top_level )

Frees an image pyramid. Parameters: pyramid  Pointer to the pyramid no_levels  The number of levels in the pyramid free_top_level  Whether to free the top level image Returns: GAN_TRUE on success, GAN_FALSE on failure. Frees an image pyramid. The free_top_levels flag indicates whether the top-level image should be freed. See also: gan_image_pyramid_build().

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