/*************************************************************************
**************************************************************************
#cat: init_dir2rad - Allocates and initializes a lookup table containing
#cat: cosine and sine values needed to convert integer IMAP
#cat: directions to angles in radians.
Input:
ndirs - the number of integer directions to be defined in a
semicircle
Output:
optr - points to the allocated/initialized DIR2RAD structure
Return Code:
Zero - successful completion
Negative - system error
**************************************************************************/
int init_dir2rad(DIR2RAD **optr, const int ndirs)
{
DIR2RAD *dir2rad;
int i;
double theta, pi_factor;
double cs, sn;
/* Allocate structure */
dir2rad = (DIR2RAD *)malloc(sizeof(DIR2RAD));
if(dir2rad == (DIR2RAD *)NULL){
fprintf(stderr, "ERROR : init_dir2rad : malloc : dir2rad\n");
return(-10);
}
/* Assign number of directions */
dir2rad->ndirs = ndirs;
/* Allocate cosine vector */
dir2rad->cos = (double *)malloc(ndirs * sizeof(double));
if(dir2rad->cos == (double *)NULL){
/* Free memory allocated to this point. */
free(dir2rad);
fprintf(stderr, "ERROR : init_dir2rad : malloc : dir2rad->cos\n");
return(-11);
}
/* Allocate sine vector */
dir2rad->sin = (double *)malloc(ndirs * sizeof(double));
if(dir2rad->sin == (double *)NULL){
/* Free memory allocated to this point. */
free(dir2rad->cos);
free(dir2rad);
fprintf(stderr, "ERROR : init_dir2rad : malloc : dir2rad->sin\n");
return(-12);
}
/* Pi_factor sets the period of the trig functions to NDIRS units in x. */
/* For example, if NDIRS==16, then pi_factor = 2(PI/16) = .3926... */
pi_factor = 2.0*M_PI/(double)ndirs;
/* Now compute cos and sin values for each direction. */
for (i = 0; i < ndirs; ++i) {
theta = (double)(i * pi_factor);
cs = cos(theta);
sn = sin(theta);
/* Need to truncate precision so that answers are consistent */
/* on different computer architectures. */
cs = trunc_dbl_precision(cs, TRUNC_SCALE);
sn = trunc_dbl_precision(sn, TRUNC_SCALE);
dir2rad->cos[i] = cs;
dir2rad->sin[i] = sn;
}
*optr = dir2rad;
return(0);
}
/*************************************************************************
**************************************************************************
#cat: dirbinarize - Determines the binary value of a grayscale pixel based
#cat: on a VALID IMAP ridge flow direction.
CAUTION: The image to which the input pixel points must be appropriately
padded to account for the radius of the rotated grid. Otherwise,
this routine may access "unkown" memory.
Input:
pptr - pointer to current grayscale pixel
idir - IMAP integer direction associated with the block the
current is in
dirbingrids - set of precomputed rotated grid offsets
Return Code:
BLACK_PIXEL - pixel intensity for BLACK
WHITE_PIXEL - pixel intensity of WHITE
**************************************************************************/
int dirbinarize(const unsigned char *pptr, const int idir,
const ROTGRIDS *dirbingrids)
{
int gx, gy, gi, cy;
int gsum, csum = 0;
int *grid;
double dcy;
/* Assign nickname pointer. */
grid = dirbingrids->grids[idir];
/* Calculate center (0-oriented) row in grid. */
dcy = (dirbingrids->grid_h-1)/(double)2.0;
/* Need to truncate precision so that answers are consistent */
/* on different computer architectures when rounding doubles. */
dcy = trunc_dbl_precision(dcy, TRUNC_SCALE);
cy = sround(dcy);
/* Initialize grid's pixel offset index to zero. */
gi = 0;
/* Initialize grid's pixel accumulator to zero */
gsum = 0;
/* Foreach row in grid ... */
for(gy = 0; gy < dirbingrids->grid_h; gy++){
/* Initialize row pixel sum to zero. */
int rsum = 0;
/* Foreach column in grid ... */
for(gx = 0; gx < dirbingrids->grid_w; gx++){
/* Accumulate next pixel along rotated row in grid. */
rsum += *(pptr+grid[gi]);
/* Bump grid's pixel offset index. */
gi++;
}
/* Accumulate row sum into grid pixel sum. */
gsum += rsum;
/* If current row is center row, then save row sum separately. */
if(gy == cy)
csum = rsum;
}
/* If the center row sum treated as an average is less than the */
/* total pixel sum in the rotated grid ... */
if((csum * dirbingrids->grid_h) < gsum)
/* Set the binary pixel to BLACK. */
return(BLACK_PIXEL);
else
/* Otherwise set the binary pixel to WHITE. */
return(WHITE_PIXEL);
}
/*************************************************************************
**************************************************************************
#cat: init_rotgrids - Allocates and initializes a set of offsets that address
#cat: individual rotated pixels within a grid.
#cat: These rotated grids are used to conduct DFT analyses
#cat: on blocks of input image data, and they are used
#cat: in isotropic binarization.
Input:
iw - width (in pixels) of the input image
ih - height (in pixels) of the input image
pad - designates the number of pixels to be padded to the perimeter
of the input image. May be passed as UNDEFINED, in which
case the specific padding required by the rotated grids
will be computed and returned in ROTGRIDS.
start_dir_angle - angle from which rotations are to start
ndirs - number of rotations to compute (within a semicircle)
grid_w - width of the grid in pixels to be rotated
grid_h - height of the grid in pixels to be rotated
relative2 - designates whether pixel offsets whould be computed
relative to the ORIGIN or the CENTER of the grid
Output:
optr - points to the allcated/initialized ROTGRIDS structure
Return Code:
Zero - successful completion
Negative - system error
**************************************************************************/
int init_rotgrids(ROTGRIDS **optr, const int iw, const int ih, const int ipad,
const double start_dir_angle, const int ndirs,
const int grid_w, const int grid_h, const int relative2)
{
ROTGRIDS *rotgrids;
double pi_offset, pi_incr;
int dir, ix, iy, grid_size, pw, grid_pad, min_dim;
int *grid;
double diag, theta, cs, sn, cx, cy;
double fxm, fym, fx, fy;
int ixt, iyt;
double pad;
/* Allocate structure */
rotgrids = (ROTGRIDS *)malloc(sizeof(ROTGRIDS));
if(rotgrids == (ROTGRIDS *)NULL){
fprintf(stderr, "ERROR : init_rotgrids : malloc : rotgrids\n");
return(-30);
}
/* Set rotgrid attributes */
rotgrids->ngrids = ndirs;
rotgrids->grid_w = grid_w;
rotgrids->grid_h = grid_h;
rotgrids->start_angle = start_dir_angle;
rotgrids->relative2 = relative2;
/* Compute pad based on diagonal of the grid */
diag = sqrt((double)((grid_w*grid_w)+(grid_h*grid_h)));
switch(relative2){
case RELATIVE2CENTER:
/* Assumption: all grid centers reside in valid/allocated memory. */
pad = (diag-1)/(double)2.0;
/* Need to truncate precision so that answers are consistent */
/* on different computer architectures when rounding doubles. */
pad = trunc_dbl_precision(pad, TRUNC_SCALE);
grid_pad = sround(pad);
break;
case RELATIVE2ORIGIN:
/* Assumption: all grid origins reside in valid/allocated memory. */
min_dim = min(grid_w, grid_h);
/* Compute pad as difference between the smallest grid dimension */
/* and the diagonal distance of the grid. */
pad = (diag-min_dim)/(double)2.0;
/* Need to truncate precision so that answers are consistent */
/* on different computer architectures when rounding doubles. */
pad = trunc_dbl_precision(pad, TRUNC_SCALE);
grid_pad = sround(pad);
break;
default:
fprintf(stderr,
"ERROR : init_rotgrids : Illegal relative flag : %d\n",
relative2);
free(rotgrids);
return(-31);
}
/* If input padding is UNDEFINED ... */
if(ipad == UNDEFINED)
/* Use the padding specifically required by the rotated grids herein. */
rotgrids->pad = grid_pad;
else{
/* Otherwise, input pad was specified, so check to make sure it is */
/* sufficiently large to handle the rotated grids herein. */
if(ipad < grid_pad){
/* If input pad is NOT large enough, then ERROR. */
fprintf(stderr, "ERROR : init_rotgrids : Pad passed is too small\n");
free(rotgrids);
return(-32);
}
/* Otherwise, use the specified input pad in computing grid offsets. */
rotgrids->pad = ipad;
}
/* Total number of points in grid */
grid_size = grid_w * grid_h;
/* Compute width of "padded" image */
pw = iw + (rotgrids->pad<<1);
/* Center coord of grid (0-oriented). */
cx = (grid_w-1)/(double)2.0;
cy = (grid_h-1)/(double)2.0;
/* Allocate list of rotgrid pointers */
rotgrids->grids = (int **)malloc(ndirs * sizeof(int *));
if(rotgrids->grids == (int **)NULL){
/* Free memory allocated to this point. */
free(rotgrids);
fprintf(stderr, "ERROR : init_rotgrids : malloc : rotgrids->grids\n");
return(-33);
}
/* Pi_offset is the offset in radians from which angles are to begin. */
pi_offset = start_dir_angle;
pi_incr = M_PI/(double)ndirs; /* if ndirs == 16, incr = 11.25 degrees */
/* For each direction to rotate a grid ... */
for (dir = 0, theta = pi_offset;
dir < ndirs; dir++, theta += pi_incr) {
/* Allocate a rotgrid */
rotgrids->grids[dir] = (int *)malloc(grid_size * sizeof(int));
if(rotgrids->grids[dir] == (int *)NULL){
/* Free memory allocated to this point. */
{ int _j; for(_j = 0; _j < dir; _j++){
free(rotgrids->grids[_j]);
}}
free(rotgrids);
fprintf(stderr,
"ERROR : init_rotgrids : malloc : rotgrids->grids[dir]\n");
return(-34);
}
/* Set pointer to current grid */
grid = rotgrids->grids[dir];
/* Compute cos and sin of current angle */
cs = cos(theta);
sn = sin(theta);
/* This next section of nested FOR loops precomputes a */
/* rotated grid. The rotation is set up to rotate a GRID_W X */
/* GRID_H grid on its center point at C=(Cx,Cy). The current */
/* pixel being rotated is P=(Ix,Iy). Therefore, we have a */
/* rotation transformation of point P about pivot point C. */
/* The rotation transformation about a pivot point in matrix */
/* form is: */
/*
+- -+
| cos(T) sin(T) 0 |
[Ix Iy 1] | -sin(T) cos(T) 0 |
| (1-cos(T))*Cx + Cy*sin(T) (1-cos(T))*Cy - Cx*sin(T) 1 |
+- -+
*/
/* Multiplying the 2 matrices and combining terms yeilds the */
/* equations for rotated coordinates (Rx, Ry): */
/* Rx = Cx + (Ix - Cx)*cos(T) - (Iy - Cy)*sin(T) */
/* Ry = Cy + (Ix - Cx)*sin(T) + (Iy - Cy)*cos(T) */
/* */
/* Care has been taken to ensure that (for example) when */
/* BLOCKSIZE==24 the rotated indices stay within a centered */
/* 34X34 area. */
/* This is important for computing an accurate padding of */
/* the input image. The rotation occurs "in-place" so that */
/* outer pixels in the grid are mapped at times from */
/* adjoining blocks. As a result, to keep from accessing */
/* "unknown" memory or pixels wrapped from the other side of */
/* the image, the input image should first be padded by */
/* PAD=round((DIAG - BLOCKSIZE)/2.0) where DIAG is the */
/* diagonal distance of the grid. */
/* For example, when BLOCKSIZE==24, Dx=34, so PAD=5. */
/* Foreach each y coord in block ... */
for (iy = 0; iy < grid_h; ++iy) {
/* Compute rotation factors dependent on Iy (include constant) */
fxm = -1.0 * ((iy - cy) * sn);
fym = ((iy - cy) * cs);
/* If offsets are to be relative to the grids origin, then */
/* we need to subtract CX and CY. */
if(relative2 == RELATIVE2ORIGIN){
fxm += cx;
fym += cy;
}
/* foreach each x coord in block ... */
for (ix = 0; ix < grid_w; ++ix) {
/* Now combine factors dependent on Iy with those of Ix */
fx = fxm + ((ix - cx) * cs);
fy = fym + ((ix - cx) * sn);
/* Need to truncate precision so that answers are consistent */
/* on different computer architectures when rounding doubles. */
fx = trunc_dbl_precision(fx, TRUNC_SCALE);
fy = trunc_dbl_precision(fy, TRUNC_SCALE);
ixt = sround(fx);
iyt = sround(fy);
/* Store the current pixels relative */
/* rotated offset. Make sure to */
/* multiply the y-component of the */
/* offset by the "padded" image width! */
*grid++ = ixt + (iyt * pw);
}/* ix */
}/* iy */
}/* dir */
*optr = rotgrids;
return(0);
}
/*************************************************************************
**************************************************************************
#cat: get_max_padding_V2 - Deterines the maximum amount of image pixel padding
#cat: required by all LFS (Version 2) processes. Padding is currently
#cat: required by the rotated grids used in DFT analyses and in
#cat: directional binarization. The NIST generalized code enables
#cat: the parameters governing these processes to be redefined, so a
#cat: check at runtime is required to determine which process
#cat: requires the most padding. By using the maximum as the padding
#cat: factor, all processes will run safely with a single padding of
#cat: the input image avoiding the need to repad for further processes.
Input:
map_windowsize - the size (in pixels) of each window centered about
each block in the image used in DFT analyses
map_windowoffset - the offset (in pixels) from the orgin of the
surrounding window to the origin of the block
dirbin_grid_w - the width (in pixels) of the rotated grids used in
directional binarization
dirbin_grid_h - the height (in pixels) of the rotated grids used in
directional binarization
Return Code:
Non-negative - the maximum padding required for all processes
**************************************************************************/
int get_max_padding_V2(const int map_windowsize, const int map_windowoffset,
const int dirbin_grid_w, const int dirbin_grid_h)
{
int dft_pad, dirbin_pad, max_pad;
double diag;
double pad;
/* 1. Compute pad required for rotated windows used in DFT analyses. */
/* Explanation of DFT padding:
B---------------------
| window |
| |
| |
| A.......______|__________
| : : |
|<-C-->: block: |
<--|--D-->: : | image
| ........ |
| | |
| | |
| | |
----------------------
|
|
|
Pixel A = Origin of entire fingerprint image
= Also origin of first block in image. Each pixel in
this block gets the same DFT results computed from
the surrounding window. Note that in general
blocks are adjacent and non-overlapping.
Pixel B = Origin of surrounding window in which DFT
analysis is conducted. Note that this window is not
completely contained in the image but extends to the
top and to the right.
Distance C = Number of pixels in which the window extends
beyond the image (map_windowoffset).
Distance D = Amount of padding required to hold the entire
rotated window in memory.
*/
/* Compute pad as difference between the MAP windowsize */
/* and the diagonal distance of the window. */
/* (DFT grids are computed with pixel offsets RELATIVE2ORIGIN.) */
diag = sqrt((double)(2.0 * map_windowsize * map_windowsize));
pad = (diag-map_windowsize)/(double)2.0;
/* Need to truncate precision so that answers are consistent */
/* on different computer architectures when rounding doubles. */
pad = trunc_dbl_precision(pad, TRUNC_SCALE);
/* Must add the window offset to the rotational padding. */
dft_pad = sround(pad) + map_windowoffset;
/* 2. Compute pad required for rotated blocks used in directional */
/* binarization. Binarization blocks are applied to each pixel */
/* in the input image. */
diag = sqrt((double)((dirbin_grid_w*dirbin_grid_w)+
(dirbin_grid_h*dirbin_grid_h)));
/* Assumption: all grid centers reside in valid/allocated memory. */
/* (Dirbin grids are computed with pixel offsets RELATIVE2CENTER.) */
pad = (diag-1)/(double)2.0;
/* Need to truncate precision so that answers are consistent */
/* on different computer architectures when rounding doubles. */
pad = trunc_dbl_precision(pad, TRUNC_SCALE);
dirbin_pad = sround(pad);
max_pad = max(dft_pad, dirbin_pad);
/* Return the maximum of the two required paddings. This padding will */
/* be sufficiently large for all purposes, so that padding of the */
/* input image will only be required once. */
return(max_pad);
}
