twain3.0/3rdparty/hgOCR/leptonica/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.
 *====================================================================*/

 /*!
  * \file binreduce.c
  * <pre>
  *
  *      Subsampled 2x reduction
  *           PIX      *pixReduceBinary2()
  *
  *      Rank filtered 2x reductions
  *           PIX      *pixReduceRankBinaryCascade()
  *           PIX      *pixReduceRankBinary2()
  *
  *      Permutation table for 2x rank binary reduction
  *           l_uint8  *makeSubsampleTab2x(void)
  * </pre>
  */

#include <string.h>
#include "allheaders.h"


  /*------------------------------------------------------------------*
   *                       Subsampled reduction                       *
   *------------------------------------------------------------------*/
   /*!
	* \brief   pixReduceBinary2()
	*
	* \param[in]    pixs
	* \param[in]    intab   [optional]; if null, a table is made here
	*                       and destroyed before exit
	* \return  pixd 2x subsampled, or NULL on error
	*
	* <pre>
	* 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().
	* </pre>
	*/
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 || pixGetDepth(pixs) != 1)
		return (PIX *)ERROR_PTR("pixs undefined or not 1 bpp", procName, NULL);

	pixGetDimensions(pixs, &ws, &hs, NULL);
	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);

	tab = (intab) ? intab : makeSubsampleTab2x();
	if (!tab) {
		pixDestroy(&pixd);
		return (PIX *)ERROR_PTR("tab not made", procName, NULL);
	}

	/* 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) LEPT_FREE(tab);
	return pixd;
}


/*------------------------------------------------------------------*
 *                   Rank filtered binary reductions                *
 *------------------------------------------------------------------*/
 /*!
  * \brief   pixReduceRankBinaryCascade()
  *
  * \param[in]    pixs    1 bpp
  * \param[in]    level1  threshold, in the set {0, 1, 2, 3, 4}
  * \param[in]    level2  threshold, in the set {0, 1, 2, 3, 4}
  * \param[in]    level3  threshold, in the set {0, 1, 2, 3, 4}
  * \param[in]    level4  threshold, in the set {0, 1, 2, 3, 4}
  * \return  pixd, or NULL on error
  *
  * <pre>
  * Notes:
  *      (1) This performs up to four cascaded 2x rank reductions.
  *      (2) Use level = 0 to truncate the cascade.
  * </pre>
  */
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) {
		LEPT_FREE(tab);
		return pix1;
	}

	pix2 = pixReduceRankBinary2(pix1, level2, tab);
	pixDestroy(&pix1);
	if (level3 <= 0) {
		LEPT_FREE(tab);
		return pix2;
	}

	pix3 = pixReduceRankBinary2(pix2, level3, tab);
	pixDestroy(&pix2);
	if (level4 <= 0) {
		LEPT_FREE(tab);
		return pix3;
	}

	pix4 = pixReduceRankBinary2(pix3, level4, tab);
	pixDestroy(&pix3);
	LEPT_FREE(tab);
	return pix4;
}


/*!
 * \brief   pixReduceRankBinary2()
 *
 * \param[in]    pixs    1 bpp
 * \param[in]    level   rank threshold: 1, 2, 3, 4
 * \param[in]    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
 *
 * <pre>
 * 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().
 * </pre>
 */
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);

	pixGetDimensions(pixs, &ws, &hs, NULL);
	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);

	tab = (intab) ? intab : makeSubsampleTab2x();
	if (!tab) {
		pixDestroy(&pixd);
		return (PIX *)ERROR_PTR("tab not made", procName, NULL);
	}

	/* 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) LEPT_FREE(tab);
	return pixd;
}


/*!
 * \brief  makeSubsampleTab2x()
 *
 * \return tab   table of 256 permutations, or NULL on error
 *
 * <pre>
 * Notes:
 *      Permutation table for 2x rank binary reduction
 *      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
 * </pre>
 */
l_uint8 *
makeSubsampleTab2x(void)
{
	l_uint8  *tab;
	l_int32   i;

	PROCNAME("makeSubsampleTab2x");

	if ((tab = (l_uint8 *)LEPT_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;
}