ee554_lib.c file documentation page
*
* -- get_image_pels --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Returns a pointer to the pixel (pel) data stored in
* an image data structure.
*
* *** n.b. ***
* This function should be used to access an image
* data structure rather than the usual
* pointer operator: img->pels
*
* Arguments in : image *img - a pointer to the image data structure
*
*
* Arguments in/out : None
*
*
* Arguments out : None
*
*
* Return values : A pointer to an array of pels
*
*
* Side effects : None
*
*
* See also :
*
*
* Modified :
*
*
*
* -- put_image_width --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Stores the value of the width passed in the
* corresponding element of an image data structure.
*
* *** n.b. ***
* These functions should be used to access an image
* data structure rather than the usual
* pointer operator: img->width
*
*
* Arguments in : image *img - pointer to the image data structure
* int width - width of the image
*
*
* Arguments in/out : None
*
*
* Arguments out : None
*
*
* Return values : None
*
*
* Side effects : None
*
*
* See also : get_image_width()
*
*
* Modified :
*
*
*
* -- put_image_height --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Stores the value of the height passed in the
* corresponding element of an image data structure.
*
* *** n.b. ***
* These functions should be used to access an image
* data structure rather than the usual
* pointer operator: img->width
*
*
* Arguments in : image *img - pointer to the image data structure
* int width - width of the image
*
*
* Arguments in/out : None
*
*
* Arguments out : None
*
*
* Return values : None
*
*
* Side effects : None
*
*
* See also : get_image_height()
*
*
* Modified :
*
*
*
* -- pgm_read_image --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Reads a PGM format image on disk into an image data
* structure. The PGM image on disk must be of type
* P5 (i.e. byte PGM). Any existing pixel data in the
* image structure will be overwritten.
*
* *** n.b. ***
* (1) It is assumed that memory for the image data
* structure is already allocated!
* (2) The size of the image in memory and the size
* of the image on disk must be equal!
*
* Note: Allocates a temporary byte buffer, reads
* into buffer, and then copies buffer to pels. This
* effectively decouples pel data type and PGM format.
* As a consequence, currently only 8-bit PGM byte
* format is supported.
*
*
*
* Arguments in : char *file_name - file name of image file on disk
* image *img - pointer to image data structure
* to be filled
*
*
* Arguments in/out : None
*
*
* Arguments out : None
*
*
* Return values : None
*
*
* Side effects : None
*
*
* See also : pgm_read_image_header(), pgm_read_image_header_bytes(),
* pgm_write_image()
*
*
* Modified :
*
*
*
* -- pgm_read_image_header --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Reads the header information of a PGM format image
* file on disk. Useful for finding out the size of
* an image on disk prior to allocating memory for
* it.
*
*
* Arguments in : char *file_name - file name of PGM image on disk
*
*
* Arguments in/out : None
*
*
* Arguments out : int *width - width of image on disk
* int *height - height of image on disk
* int *max_gl - maximum grey level in image on disk
*
*
* Return values : None
*
*
* Side effects : None
*
*
* See also : pgm_read_image(), pgm_read_image_header_bytes(),
* pgm_write_image()
*
*
* Modified :
*
*
*
* -- pgm_read_image_header_bytes --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Reads the header information of a PGM format image
* file on disk from a file pointer which points to the
* ***already opened*** file.
*
*
*
* Arguments in : FILE *fpfile - file pointer to *opened* image file
*
*
* Arguments in/out : None
*
*
* Arguments out : int *width - width of image on disk
* int *height - height of image on disk
* int *max_gl - maximum grey level in image on disk
*
*
* Return values : None
*
*
* Side effects : None
*
*
* See also : pgm_read_image(), pgm_read_image_header(),
* pgm_write_image()
*
*
* Modified : 13/07/2001 - Vivien Chappelier: fixed bug in parser
*
*
*
* -- calc_MSE_image --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Calculates the Mean Square Error (MSE) between two
* input images
*
*
* Arguments in : image *img1 - pointer to the first image
* image *img2 - pointer to the second image
*
*
* Arguments in/out : None
*
*
* Arguments out : None
*
*
* Return values : The MSE as a double value
*
*
* Side effects : None
*
*
* See also : calc_PSNR_image()
*
*
* Modified :
*
*
*
* -- estimate_bits_image --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Estimates (very roughly!) the number of bits
* required to code an image
*
*
* Arguments in : image *img - pointer to the image
* int - indicates whether -ve pel values
* are present
* (1 -> -ve and +ve pel values)
* (0 -> only +ve pel values)
*
*
* Arguments in/out : None
*
*
* Arguments out : None
*
*
* Return values : The estimated number of bits
*
*
* Side effects : None
*
*
* See also : estimate_bits_pel() and estimate_bits_pel_signed()
*
*
* Modified :
*
*
*
* -- estimate_bits_pel --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Estimates (very roughly!) the number of bits
* required to code a +ve pel value
*
*
* Arguments in : pel pval - the pel value
*
*
* Arguments in/out : None
*
*
* Arguments out : None
*
*
* Return values : The estimated number of bits
*
*
* Side effects : None
*
*
* See also : estimate_bits_image() and estimate_bits_pel_signed()
*
*
* Modified :
*
*
*
* -- estimate_bits_pel_signed --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Estimates (very roughly!) the number of bits
* required to code a pel value where the value
* could be -ve or +ve (e.g. a difference image)
*
*
* Arguments in : pel pval - the pel value
*
*
* Arguments in/out : None
*
*
* Arguments out : None
*
*
* Return values : The estimated number of bits
*
*
* Side effects : None
*
*
* See also : estimate_bits_image() and estimate_bits_pel()
*
*
* Modified :
*
*
*
* -- copy_image --
*
* Author : Noel O'Connor
*
*
* Created : 02/08/2000
*
*
* Description : Copies the pixel data of one image to another
* (thereby overwriting its contents). Assumes
* *both* images are already allocated.
*
*
* Arguments in : image *in - a pointer to the image to be copied
*
*
* Arguments in/out : None
*
*
* Arguments out : image *out - where to copy the input image
*
*
* Return values : None
*
*
* Side effects : None
*
*
* See also :
*
*
* Modified :
*
*
Last edited: 16-Aug-2001