third-party/leptonica/src/binreduce.c
/*====================================================================*
- Copyright (C) 2001 Leptonica. All rights reserved.
-
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions
- are met:
- 1. Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
- 2. Redistributions in binary form must reproduce the above
- copyright notice, this list of conditions and the following
- disclaimer in the documentation and/or other materials
- provided with the distribution.
-
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY
- CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*====================================================================*/
/*
* binreduce.c
*
* Subsampled 2x reduction
* PIX *pixReduceBinary2()
*
* Rank filtered 2x reductions
* PIX *pixReduceRankBinaryCascade()
* PIX *pixReduceRankBinary2()
*
* Permutation table for 2x rank binary reduction
* l_uint8 *makeSubsampleTab2x(void)
*/
#include <string.h>
#include "allheaders.h"
/*------------------------------------------------------------------*
* Subsampled reduction *
*------------------------------------------------------------------*/
/*!
* pixReduceBinary2()
*
* Input: pixs
* tab (<optional>; if null, a table is made here
* and destroyed before exit)
* Return: pixd (2x subsampled), or null on error
*
* Notes:
* (1) After folding, the data is in bytes 0 and 2 of the word,
* and the bits in each byte are in the following order
* (with 0 being the leftmost originating pair and 7 being
* the rightmost originating pair):
* 0 4 1 5 2 6 3 7
* These need to be permuted to
* 0 1 2 3 4 5 6 7
* which is done with an 8-bit table generated by makeSubsampleTab2x().
*/
PIX *
pixReduceBinary2(PIX *pixs,
l_uint8 *intab)
{
l_uint8 byte0, byte1;
l_uint8 *tab;
l_uint16 shortd;
l_int32 i, id, j, ws, hs, wpls, wpld, wplsi;
l_uint32 word;
l_uint32 *datas, *datad, *lines, *lined;
PIX *pixd;
PROCNAME("pixReduceBinary2");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 1)
return (PIX *)ERROR_PTR("pixs not binary", procName, NULL);
if (intab) { /* use input table */
tab = intab;
} else {
if ((tab = makeSubsampleTab2x()) == NULL)
return (PIX *)ERROR_PTR("tab not made", procName, NULL);
}
ws = pixGetWidth(pixs);
hs = pixGetHeight(pixs);
if (hs <= 1)
return (PIX *)ERROR_PTR("hs must be at least 2", procName, NULL);
wpls = pixGetWpl(pixs);
datas = pixGetData(pixs);
if ((pixd = pixCreate(ws / 2, hs / 2, 1)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, 0.5, 0.5);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
/* e.g., if ws = 65: wd = 32, wpls = 3, wpld = 1 --> trouble */
wplsi = L_MIN(wpls, 2 * wpld); /* iterate over this number of words */
for (i = 0, id = 0; i < hs - 1; i += 2, id++) {
lines = datas + i * wpls;
lined = datad + id * wpld;
for (j = 0; j < wplsi; j++) {
word = *(lines + j);
word = word & 0xaaaaaaaa; /* mask */
word = word | (word << 7); /* fold; data in bytes 0 & 2 */
byte0 = word >> 24;
byte1 = (word >> 8) & 0xff;
shortd = (tab[byte0] << 8) | tab[byte1];
SET_DATA_TWO_BYTES(lined, j, shortd);
}
}
if (intab == NULL)
FREE(tab);
return pixd;
}
/*------------------------------------------------------------------*
* Rank filtered binary reductions *
*------------------------------------------------------------------*/
/*!
* pixReduceRankBinaryCascade()
*
* Input: pixs (1 bpp)
* level1, ... level 4 (thresholds, in the set {0, 1, 2, 3, 4})
* Return: pixd, or null on error
*
* Notes:
* (1) This performs up to four cascaded 2x rank reductions.
* (2) Use level = 0 to truncate the cascade.
*/
PIX *
pixReduceRankBinaryCascade(PIX *pixs,
l_int32 level1,
l_int32 level2,
l_int32 level3,
l_int32 level4)
{
PIX *pix1, *pix2, *pix3, *pix4;
l_uint8 *tab;
PROCNAME("pixReduceRankBinaryCascade");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 1)
return (PIX *)ERROR_PTR("pixs must be binary", procName, NULL);
if (level1 > 4 || level2 > 4 || level3 > 4 || level4 > 4)
return (PIX *)ERROR_PTR("levels must not exceed 4", procName, NULL);
if (level1 <= 0) {
L_WARNING("no reduction because level1 not > 0\n", procName);
return pixCopy(NULL, pixs);
}
if ((tab = makeSubsampleTab2x()) == NULL)
return (PIX *)ERROR_PTR("tab not made", procName, NULL);
pix1 = pixReduceRankBinary2(pixs, level1, tab);
if (level2 <= 0) {
FREE(tab);
return pix1;
}
pix2 = pixReduceRankBinary2(pix1, level2, tab);
pixDestroy(&pix1);
if (level3 <= 0) {
FREE(tab);
return pix2;
}
pix3 = pixReduceRankBinary2(pix2, level3, tab);
pixDestroy(&pix2);
if (level4 <= 0) {
FREE(tab);
return pix3;
}
pix4 = pixReduceRankBinary2(pix3, level4, tab);
pixDestroy(&pix3);
FREE(tab);
return pix4;
}
/*!
* pixReduceRankBinary2()
*
* Input: pixs (1 bpp)
* level (rank threshold: 1, 2, 3, 4)
* intab (<optional>; if null, a table is made here
* and destroyed before exit)
* Return: pixd (1 bpp, 2x rank threshold reduced), or null on error
*
* Notes:
* (1) pixd is downscaled by 2x from pixs.
* (2) The rank threshold specifies the minimum number of ON
* pixels in each 2x2 region of pixs that are required to
* set the corresponding pixel ON in pixd.
* (3) Rank filtering is done to the UL corner of each 2x2 pixel block,
* using only logical operations. Then these pixels are chosen
* in the 2x subsampling process, subsampled, as described
* above in pixReduceBinary2().
*/
PIX *
pixReduceRankBinary2(PIX *pixs,
l_int32 level,
l_uint8 *intab)
{
l_uint8 byte0, byte1;
l_uint8 *tab;
l_uint16 shortd;
l_int32 i, id, j, ws, hs, wpls, wpld, wplsi;
l_uint32 word1, word2, word3, word4;
l_uint32 *datas, *datad, *lines, *lined;
PIX *pixd;
PROCNAME("pixReduceRankBinary2");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 1)
return (PIX *)ERROR_PTR("pixs not binary", procName, NULL);
if (level < 1 || level > 4)
return (PIX *)ERROR_PTR("level must be in set {1,2,3,4}",
procName, NULL);
if (intab) { /* use input table */
tab = intab;
} else {
if ((tab = makeSubsampleTab2x()) == NULL)
return (PIX *)ERROR_PTR("tab not made", procName, NULL);
}
ws = pixGetWidth(pixs);
hs = pixGetHeight(pixs);
if (hs <= 1)
return (PIX *)ERROR_PTR("hs must be at least 2", procName, NULL);
wpls = pixGetWpl(pixs);
datas = pixGetData(pixs);
if ((pixd = pixCreate(ws / 2, hs / 2, 1)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
pixCopyResolution(pixd, pixs);
pixScaleResolution(pixd, 0.5, 0.5);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
/* e.g., if ws = 65: wd = 32, wpls = 3, wpld = 1 --> trouble */
wplsi = L_MIN(wpls, 2 * wpld); /* iterate over this number of words */
switch (level)
{
case 1:
for (i = 0, id = 0; i < hs - 1; i += 2, id++) {
lines = datas + i * wpls;
lined = datad + id * wpld;
for (j = 0; j < wplsi; j++) {
word1 = *(lines + j);
word2 = *(lines + wpls + j);
/* OR/OR */
word2 = word1 | word2;
word2 = word2 | (word2 << 1);
word2 = word2 & 0xaaaaaaaa; /* mask */
word1 = word2 | (word2 << 7); /* fold; data in bytes 0 & 2 */
byte0 = word1 >> 24;
byte1 = (word1 >> 8) & 0xff;
shortd = (tab[byte0] << 8) | tab[byte1];
SET_DATA_TWO_BYTES(lined, j, shortd);
}
}
break;
case 2:
for (i = 0, id = 0; i < hs - 1; i += 2, id++) {
lines = datas + i * wpls;
lined = datad + id * wpld;
for (j = 0; j < wplsi; j++) {
word1 = *(lines + j);
word2 = *(lines + wpls + j);
/* (AND/OR) OR (OR/AND) */
word3 = word1 & word2;
word3 = word3 | (word3 << 1);
word4 = word1 | word2;
word4 = word4 & (word4 << 1);
word2 = word3 | word4;
word2 = word2 & 0xaaaaaaaa; /* mask */
word1 = word2 | (word2 << 7); /* fold; data in bytes 0 & 2 */
byte0 = word1 >> 24;
byte1 = (word1 >> 8) & 0xff;
shortd = (tab[byte0] << 8) | tab[byte1];
SET_DATA_TWO_BYTES(lined, j, shortd);
}
}
break;
case 3:
for (i = 0, id = 0; i < hs - 1; i += 2, id++) {
lines = datas + i * wpls;
lined = datad + id * wpld;
for (j = 0; j < wplsi; j++) {
word1 = *(lines + j);
word2 = *(lines + wpls + j);
/* (AND/OR) AND (OR/AND) */
word3 = word1 & word2;
word3 = word3 | (word3 << 1);
word4 = word1 | word2;
word4 = word4 & (word4 << 1);
word2 = word3 & word4;
word2 = word2 & 0xaaaaaaaa; /* mask */
word1 = word2 | (word2 << 7); /* fold; data in bytes 0 & 2 */
byte0 = word1 >> 24;
byte1 = (word1 >> 8) & 0xff;
shortd = (tab[byte0] << 8) | tab[byte1];
SET_DATA_TWO_BYTES(lined, j, shortd);
}
}
break;
case 4:
for (i = 0, id = 0; i < hs - 1; i += 2, id++) {
lines = datas + i * wpls;
lined = datad + id * wpld;
for (j = 0; j < wplsi; j++) {
word1 = *(lines + j);
word2 = *(lines + wpls + j);
/* AND/AND */
word2 = word1 & word2;
word2 = word2 & (word2 << 1);
word2 = word2 & 0xaaaaaaaa; /* mask */
word1 = word2 | (word2 << 7); /* fold; data in bytes 0 & 2 */
byte0 = word1 >> 24;
byte1 = (word1 >> 8) & 0xff;
shortd = (tab[byte0] << 8) | tab[byte1];
SET_DATA_TWO_BYTES(lined, j, shortd);
}
}
break;
}
if (!intab)
FREE(tab);
return pixd;
}
/*!
* makeSubsampleTab2x()
*
* This table permutes the bits in a byte, from
* 0 4 1 5 2 6 3 7
* to
* 0 1 2 3 4 5 6 7
*/
l_uint8 *
makeSubsampleTab2x(void)
{
l_uint8 *tab;
l_int32 i;
PROCNAME("makeSubsampleTab2x");
if ((tab = (l_uint8 *) CALLOC(256, sizeof(l_uint8))) == NULL)
return (l_uint8 *)ERROR_PTR("tab not made", procName, NULL);
for (i = 0; i < 256; i++)
tab[i] = ((i & 0x01) ) | /* 7 */
((i & 0x04) >> 1) | /* 6 */
((i & 0x10) >> 2) | /* 5 */
((i & 0x40) >> 3) | /* 4 */
((i & 0x02) << 3) | /* 3 */
((i & 0x08) << 2) | /* 2 */
((i & 0x20) << 1) | /* 1 */
((i & 0x80) ); /* 0 */
return tab;
}