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libfprint/libfprint/nbis/mindtct/block.c
Bastien Nocera 9fb789dc78 nbis: Update to NBIS 5.0.0 
This updates NBIS to its latest 5.0.0 version, dated 04/03/2015, from a
1.x version, dated 2007.

Original sources are available at:
https://www.nist.gov/itl/iad/image-group/products-and-services/image-group-open-source-server-nigos#Releases

And full change log at:
https://www.nist.gov/sites/default/files/documents/2016/12/14/changelog.txt
2018-08-27 20:01:00 +02:00

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/*******************************************************************************
License:
This software and/or related materials was developed at the National Institute
of Standards and Technology (NIST) by employees of the Federal Government
in the course of their official duties. Pursuant to title 17 Section 105
of the United States Code, this software is not subject to copyright
protection and is in the public domain.
This software and/or related materials have been determined to be not subject
to the EAR (see Part 734.3 of the EAR for exact details) because it is
a publicly available technology and software, and is freely distributed
to any interested party with no licensing requirements. Therefore, it is
permissible to distribute this software as a free download from the internet.
Disclaimer:
This software and/or related materials was developed to promote biometric
standards and biometric technology testing for the Federal Government
in accordance with the USA PATRIOT Act and the Enhanced Border Security
and Visa Entry Reform Act. Specific hardware and software products identified
in this software were used in order to perform the software development.
In no case does such identification imply recommendation or endorsement
by the National Institute of Standards and Technology, nor does it imply that
the products and equipment identified are necessarily the best available
for the purpose.
This software and/or related materials are provided "AS-IS" without warranty
of any kind including NO WARRANTY OF PERFORMANCE, MERCHANTABILITY,
NO WARRANTY OF NON-INFRINGEMENT OF ANY 3RD PARTY INTELLECTUAL PROPERTY
or FITNESS FOR A PARTICULAR PURPOSE or for any purpose whatsoever, for the
licensed product, however used. In no event shall NIST be liable for any
damages and/or costs, including but not limited to incidental or consequential
damages of any kind, including economic damage or injury to property and lost
profits, regardless of whether NIST shall be advised, have reason to know,
or in fact shall know of the possibility.
By using this software, you agree to bear all risk relating to quality,
use and performance of the software and/or related materials. You agree
to hold the Government harmless from any claim arising from your use
of the software.
*******************************************************************************/
/***********************************************************************
LIBRARY: LFS - NIST Latent Fingerprint System
FILE: BLOCK.C
AUTHOR: Michael D. Garris
DATE: 03/16/1999
UPDATED: 10/04/1999 Version 2 by MDG
UPDATED: 03/16/2005 by MDG
Contains routines responsible for partitioning arbitrarily-
sized images into equally-sized blocks as part of the NIST
Latent Fingerprint System (LFS).
***********************************************************************
ROUTINES:
block_offsets()
low_contrast_block()
find_valid_block()
set_margin_blocks()
***********************************************************************/
#include <stdio.h>
#include <lfs.h>
/*************************************************************************
**************************************************************************
#cat: block_offsets - Divides an image into mw X mh equally sized blocks,
#cat: returning a list of offsets to the top left corner of each block.
#cat: For images that are even multiples of BLOCKSIZE, blocks do not
#cat: not overlap and are immediately adjacent to each other. For image
#cat: that are NOT even multiples of BLOCKSIZE, blocks continue to be
#cat: non-overlapping up to the last column and/or last row of blocks.
#cat: In these cases the blocks are adjacent to the edge of the image and
#cat: extend inwards BLOCKSIZE units, overlapping the neighboring column
#cat: or row of blocks. This routine also accounts for image padding
#cat: which makes things a little more "messy". This routine is primarily
#cat: responsible providing the ability to processs arbitrarily-sized
#cat: images. The strategy used here is simple, but others are possible.
Input:
iw - width (in pixels) of the orginal input image
ih - height (in pixels) of the orginal input image
pad - the padding (in pixels) required to support the desired
range of block orientations for DFT analysis. This padding
is required along the entire perimeter of the input image.
For certain applications, the pad may be zero.
blocksize - the width and height (in pixels) of each image block
Output:
optr - points to the list of pixel offsets to the origin of
each block in the "padded" input image
ow - the number of horizontal blocks in the input image
oh - the number of vertical blocks in the input image
Return Code:
Zero - successful completion
Negative - system error
**************************************************************************/
int block_offsets(int **optr, int *ow, int *oh,
const int iw, const int ih, const int pad, const int blocksize)
{
int *blkoffs, bx, by, bw, bh, bi, bsize;
int blkrow_start, blkrow_size, offset;
int lastbw, lastbh;
int pad2, pw, ph;
/* Test if unpadded image is smaller than a single block */
if((iw < blocksize) || (ih < blocksize)){
fprintf(stderr,
"ERROR : block_offsets : image must be at least %d by %d in size\n",
blocksize, blocksize);
return(-80);
}
/* Compute padded width and height of image */
pad2 = pad<<1;
pw = iw + pad2;
ph = ih + pad2;
/* Compute the number of columns and rows of blocks in the image. */
/* Take the ceiling to account for "leftovers" at the right and */
/* bottom of the unpadded image */
bw = (int)ceil(iw / (double)blocksize);
bh = (int)ceil(ih / (double)blocksize);
/* Total number of blocks in the image */
bsize = bw*bh;
/* The index of the last column */
lastbw = bw - 1;
/* The index of the last row */
lastbh = bh - 1;
/* Allocate list of block offsets */
blkoffs = (int *)malloc(bsize * sizeof(int));
if(blkoffs == (int *)NULL){
fprintf(stderr, "ERROR : block_offsets : malloc : blkoffs\n");
return(-81);
}
/* Current block index */
bi = 0;
/* Current offset from top of padded image to start of new row of */
/* unpadded image blocks. It is initialize to account for the */
/* padding and will always be indented the size of the padding */
/* from the left edge of the padded image. */
blkrow_start = (pad * pw) + pad;
/* Number of pixels in a row of blocks in the padded image */
blkrow_size = pw * blocksize; /* row width X block height */
/* Foreach non-overlapping row of blocks in the image */
for(by = 0; by < lastbh; by++){
/* Current offset from top of padded image to beginning of */
/* the next block */
offset = blkrow_start;
/* Foreach non-overlapping column of blocks in the image */
for(bx = 0; bx < lastbw; bx++){
/* Store current block offset */
blkoffs[bi++] = offset;
/* Bump to the beginning of the next block */
offset += blocksize;
}
/* Compute and store "left-over" block in row. */
/* This is the block in the last column of row. */
/* Start at far right edge of unpadded image data */
/* and come in BLOCKSIZE pixels. */
blkoffs[bi++] = blkrow_start + iw - blocksize;
/* Bump to beginning of next row of blocks */
blkrow_start += blkrow_size;
}
/* Compute and store "left-over" row of blocks at bottom of image */
/* Start at bottom edge of unpadded image data and come up */
/* BLOCKSIZE pixels. This too must account for padding. */
blkrow_start = ((pad + ih - blocksize) * pw) + pad;
/* Start the block offset for the last row at this point */
offset = blkrow_start;
/* Foreach non-overlapping column of blocks in last row of the image */
for(bx = 0; bx < lastbw; bx++){
/* Store current block offset */
blkoffs[bi++] = offset;
/* Bump to the beginning of the next block */
offset += blocksize;
}
/* Compute and store last "left-over" block in last row. */
/* Start at right edge of unpadded image data and come in */
/* BLOCKSIZE pixels. */
blkoffs[bi++] = blkrow_start + iw - blocksize;
*optr = blkoffs;
*ow = bw;
*oh = bh;
return(0);
}
/*************************************************************************
#cat: low_contrast_block - Takes the offset to an image block of specified
#cat: dimension, and analyzes the pixel intensities in the block
#cat: to determine if there is sufficient contrast for further
#cat: processing.
Input:
blkoffset - byte offset into the padded input image to the origin of
the block to be analyzed
blocksize - dimension (in pixels) of the width and height of the block
(passing separate blocksize from LFSPARMS on purpose)
pdata - padded input image data (8 bits [0..256) grayscale)
pw - width (in pixels) of the padded input image
ph - height (in pixels) of the padded input image
lfsparms - parameters and thresholds for controlling LFS
Return Code:
TRUE - block has sufficiently low contrast
FALSE - block has sufficiently hight contrast
Negative - system error
**************************************************************************
**************************************************************************/
int low_contrast_block(const int blkoffset, const int blocksize,
unsigned char *pdata, const int pw, const int ph,
const LFSPARMS *lfsparms)
{
int pixtable[IMG_6BIT_PIX_LIMIT], numpix;
int px, py, pi;
unsigned char *sptr, *pptr;
int delta;
double tdbl;
int prctmin = 0, prctmax = 0, prctthresh;
int pixsum, found;
numpix = blocksize*blocksize;
memset(pixtable, 0, IMG_6BIT_PIX_LIMIT*sizeof(int));
tdbl = (lfsparms->percentile_min_max/100.0) * (double)(numpix-1);
tdbl = trunc_dbl_precision(tdbl, TRUNC_SCALE);
prctthresh = sround(tdbl);
sptr = pdata+blkoffset;
for(py = 0; py < blocksize; py++){
pptr = sptr;
for(px = 0; px < blocksize; px++){
pixtable[*pptr]++;
pptr++;
}
sptr += pw;
}
pi = 0;
pixsum = 0;
found = FALSE;
while(pi < IMG_6BIT_PIX_LIMIT){
pixsum += pixtable[pi];
if(pixsum >= prctthresh){
prctmin = pi;
found = TRUE;
break;
}
pi++;
}
if(!found){
fprintf(stderr,
"ERROR : low_contrast_block : min percentile pixel not found\n");
return(-510);
}
pi = IMG_6BIT_PIX_LIMIT-1;
pixsum = 0;
found = FALSE;
while(pi >= 0){
pixsum += pixtable[pi];
if(pixsum >= prctthresh){
prctmax = pi;
found = TRUE;
break;
}
pi--;
}
if(!found){
fprintf(stderr,
"ERROR : low_contrast_block : max percentile pixel not found\n");
return(-511);
}
delta = prctmax - prctmin;
if(delta < lfsparms->min_contrast_delta)
return(TRUE);
else
return(FALSE);
}
/*************************************************************************
**************************************************************************
#cat: find_valid_block - Take a Direction Map, Low Contrast Map,
#cat: Starting block address, a direction and searches the
#cat: maps in the specified direction until either a block valid
#cat: direction is encountered or a block flagged as LOW CONTRAST
#cat: is encountered. If a valid direction is located, it and the
#cat: address of the corresponding block are returned with a
#cat: code of FOUND. Otherwise, a code of NOT_FOUND is returned.
Input:
direction_map - map of blocks containing directional ridge flows
low_contrast_map - map of blocks flagged as LOW CONTRAST
sx - X-block coord where search starts in maps
sy - Y-block coord where search starts in maps
mw - number of blocks horizontally in the maps
mh - number of blocks vertically in the maps
x_incr - X-block increment to direct search
y_incr - Y-block increment to direct search
Output:
nbr_dir - valid direction found
nbr_x - X-block coord where valid direction found
nbr_y - Y-block coord where valid direction found
Return Code:
FOUND - neighboring block with valid direction found
NOT_FOUND - neighboring block with valid direction NOT found
**************************************************************************/
int find_valid_block(int *nbr_dir, int *nbr_x, int *nbr_y,
int *direction_map, int *low_contrast_map,
const int sx, const int sy,
const int mw, const int mh,
const int x_incr, const int y_incr)
{
int x, y, dir;
/* Initialize starting block coords. */
x = sx + x_incr;
y = sy + y_incr;
/* While we are not outside the boundaries of the map ... */
while((x >= 0) && (x < mw) && (y >= 0) && (y < mh)){
/* Stop unsuccessfully if we encounter a LOW CONTRAST block. */
if(*(low_contrast_map+(y*mw)+x))
return(NOT_FOUND);
/* Stop successfully if we encounter a block with valid direction. */
if((dir = *(direction_map+(y*mw)+x)) >= 0){
*nbr_dir = dir;
*nbr_x = x;
*nbr_y = y;
return(FOUND);
}
/* Otherwise, advance to the next block in the map. */
x += x_incr;
y += y_incr;
}
/* If we get here, then we did not find a valid block in the given */
/* direction in the map. */
return(NOT_FOUND);
}
/*************************************************************************
**************************************************************************
#cat: set_margin_blocks - Take an image map and sets its perimeter values to
#cat: the specified value.
Input:
map - map of blocks to be modified
mw - number of blocks horizontally in the map
mh - number of blocks vertically in the map
margin_value - value to be assigned to the perimeter blocks
Output:
map - resulting map
**************************************************************************/
void set_margin_blocks(int *map, const int mw, const int mh,
const int margin_value)
{
int x, y;
int *ptr1, *ptr2;
ptr1 = map;
ptr2 = map+((mh-1)*mw);
for(x = 0; x < mw; x++){
*ptr1++ = margin_value;
*ptr2++ = margin_value;
}
ptr1 = map + mw;
ptr2 = map + mw + mw - 1;
for(y = 1; y < mh-1; y++){
*ptr1 = margin_value;
*ptr2 = margin_value;
ptr1 += mw;
ptr2 += mw;
}
}
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