250 lines
9.8 KiB
C
250 lines
9.8 KiB
C
/*******************************************************************************
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License:
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This software was developed at the National Institute of Standards and
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Technology (NIST) by employees of the Federal Government in the course
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of their official duties. Pursuant to title 17 Section 105 of the
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United States Code, this software is not subject to copyright protection
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and is in the public domain. NIST assumes no responsibility whatsoever for
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its use by other parties, and makes no guarantees, expressed or implied,
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about its quality, reliability, or any other characteristic.
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Disclaimer:
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This software was developed to promote biometric standards and biometric
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technology testing for the Federal Government in accordance with the USA
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PATRIOT Act and the Enhanced Border Security and Visa Entry Reform Act.
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Specific hardware and software products identified in this software were used
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in order to perform the software development. In no case does such
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identification imply recommendation or endorsement by the National Institute
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of Standards and Technology, nor does it imply that the products and equipment
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identified are necessarily the best available for the purpose.
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*******************************************************************************/
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/***********************************************************************
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LIBRARY: LFS - NIST Latent Fingerprint System
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FILE: BINAR.C
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AUTHOR: Michael D. Garris
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DATE: 03/16/1999
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UPDATED: 10/04/1999 Version 2 by MDG
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UPDATED: 03/16/2005 by MDG
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Contains routines responsible for binarizing a grayscale image based
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on an arbitrarily-sized image and its precomputed direcitonal ridge
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flow (IMAP) as part of the NIST Latent Fingerprint System (LFS).
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***********************************************************************
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ROUTINES:
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binarize_V2()
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binarize_image_V2()
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dirbinarize()
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***********************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <lfs.h>
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/*************************************************************************
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**************************************************************************
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#cat: binarize_V2 - Takes a padded grayscale input image and its associated
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#cat: Direction Map and produces a binarized version of the
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#cat: image. It then fills horizontal and vertical "holes" in
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#cat: the binary image results. Note that the input image must
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#cat: be padded sufficiently to contain in memory rotated
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#cat: directional binarization grids applied to pixels along the
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#cat: perimeter of the input image.
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Input:
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pdata - padded input grayscale image
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pw - padded width (in pixels) of input image
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ph - padded height (in pixels) of input image
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direction_map - 2-D vector of discrete ridge flow directions
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mw - width (in blocks) of the map
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mh - height (in blocks) of the map
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dirbingrids - set of rotated grid offsets used for directional
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binarization
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lfsparms - parameters and thresholds for controlling LFS
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Output:
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odata - points to created (unpadded) binary image
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ow - width of binary image
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oh - height of binary image
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Return Code:
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Zero - successful completion
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Negative - system error
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**************************************************************************/
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int binarize_V2(unsigned char **odata, int *ow, int *oh,
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unsigned char *pdata, const int pw, const int ph,
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int *direction_map, const int mw, const int mh,
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const ROTGRIDS *dirbingrids, const LFSPARMS *lfsparms)
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{
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unsigned char *bdata;
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int i, bw, bh, ret; /* return code */
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/* 1. Binarize the padded input image using directional block info. */
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if((ret = binarize_image_V2(&bdata, &bw, &bh, pdata, pw, ph,
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direction_map, mw, mh,
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lfsparms->blocksize, dirbingrids))){
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return(ret);
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}
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/* 2. Fill black and white holes in binary image. */
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/* LFS scans the binary image, filling holes, 3 times. */
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for(i = 0; i < lfsparms->num_fill_holes; i++)
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fill_holes(bdata, bw, bh);
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/* Return binarized input image. */
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*odata = bdata;
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*ow = bw;
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*oh = bh;
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return(0);
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}
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/*************************************************************************
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**************************************************************************
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#cat: binarize_image_V2 - Takes a grayscale input image and its associated
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#cat: Direction Map and generates a binarized version of the
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#cat: image. Note that there is no "Isotropic" binarization
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#cat: used in this version.
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Input:
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pdata - padded input grayscale image
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pw - padded width (in pixels) of input image
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ph - padded height (in pixels) of input image
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direction_map - 2-D vector of discrete ridge flow directions
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mw - width (in blocks) of the map
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mh - height (in blocks) of the map
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blocksize - dimension (in pixels) of each NMAP block
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dirbingrids - set of rotated grid offsets used for directional
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binarization
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Output:
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odata - points to binary image results
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ow - points to binary image width
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oh - points to binary image height
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Return Code:
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Zero - successful completion
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Negative - system error
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**************************************************************************/
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int binarize_image_V2(unsigned char **odata, int *ow, int *oh,
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unsigned char *pdata, const int pw, const int ph,
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const int *direction_map, const int mw, const int mh,
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const int blocksize, const ROTGRIDS *dirbingrids)
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{
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int ix, iy, bw, bh, bx, by, mapval;
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unsigned char *bdata, *bptr;
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unsigned char *pptr, *spptr;
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/* Compute dimensions of "unpadded" binary image results. */
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bw = pw - (dirbingrids->pad<<1);
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bh = ph - (dirbingrids->pad<<1);
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bdata = (unsigned char *)malloc(bw*bh*sizeof(unsigned char));
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if(bdata == (unsigned char *)NULL){
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fprintf(stderr, "ERROR : binarize_image_V2 : malloc : bdata\n");
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return(-600);
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}
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bptr = bdata;
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spptr = pdata + (dirbingrids->pad * pw) + dirbingrids->pad;
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for(iy = 0; iy < bh; iy++){
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/* Set pixel pointer to start of next row in grid. */
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pptr = spptr;
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for(ix = 0; ix < bw; ix++){
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/* Compute which block the current pixel is in. */
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bx = (int)(ix/blocksize);
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by = (int)(iy/blocksize);
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/* Get corresponding value in Direction Map. */
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mapval = *(direction_map + (by*mw) + bx);
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/* If current block has has INVALID direction ... */
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if(mapval == INVALID_DIR)
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/* Set binary pixel to white (255). */
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*bptr = WHITE_PIXEL;
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/* Otherwise, if block has a valid direction ... */
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else /*if(mapval >= 0)*/
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/* Use directional binarization based on block's direction. */
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*bptr = dirbinarize(pptr, mapval, dirbingrids);
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/* Bump input and output pixel pointers. */
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pptr++;
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bptr++;
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}
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/* Bump pointer to the next row in padded input image. */
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spptr += pw;
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}
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*odata = bdata;
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*ow = bw;
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*oh = bh;
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return(0);
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}
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/*************************************************************************
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**************************************************************************
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#cat: dirbinarize - Determines the binary value of a grayscale pixel based
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#cat: on a VALID IMAP ridge flow direction.
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CAUTION: The image to which the input pixel points must be appropriately
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padded to account for the radius of the rotated grid. Otherwise,
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this routine may access "unkown" memory.
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Input:
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pptr - pointer to current grayscale pixel
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idir - IMAP integer direction associated with the block the
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current is in
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dirbingrids - set of precomputed rotated grid offsets
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Return Code:
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BLACK_PIXEL - pixel intensity for BLACK
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WHITE_PIXEL - pixel intensity of WHITE
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**************************************************************************/
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int dirbinarize(const unsigned char *pptr, const int idir,
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const ROTGRIDS *dirbingrids)
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{
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int gx, gy, gi, cy;
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int rsum, gsum, csum = 0;
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int *grid;
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double dcy;
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/* Assign nickname pointer. */
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grid = dirbingrids->grids[idir];
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/* Calculate center (0-oriented) row in grid. */
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dcy = (dirbingrids->grid_h-1)/(double)2.0;
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/* Need to truncate precision so that answers are consistent */
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/* on different computer architectures when rounding doubles. */
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dcy = trunc_dbl_precision(dcy, TRUNC_SCALE);
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cy = sround(dcy);
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/* Initialize grid's pixel offset index to zero. */
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gi = 0;
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/* Initialize grid's pixel accumulator to zero */
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gsum = 0;
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/* Foreach row in grid ... */
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for(gy = 0; gy < dirbingrids->grid_h; gy++){
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/* Initialize row pixel sum to zero. */
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rsum = 0;
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/* Foreach column in grid ... */
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for(gx = 0; gx < dirbingrids->grid_w; gx++){
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/* Accumulate next pixel along rotated row in grid. */
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rsum += *(pptr+grid[gi]);
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/* Bump grid's pixel offset index. */
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gi++;
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}
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/* Accumulate row sum into grid pixel sum. */
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gsum += rsum;
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/* If current row is center row, then save row sum separately. */
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if(gy == cy)
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csum = rsum;
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}
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/* If the center row sum treated as an average is less than the */
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/* total pixel sum in the rotated grid ... */
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if((csum * dirbingrids->grid_h) < gsum)
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/* Set the binary pixel to BLACK. */
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return(BLACK_PIXEL);
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else
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/* Otherwise set the binary pixel to WHITE. */
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return(WHITE_PIXEL);
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}
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