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twain3.0/3rdparty/hgOCR/leptonica/pixlabel.c

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2021-11-20 06:24:33 +00:00
/*====================================================================*
- 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 pixlabel.c
* <pre>
*
* Label pixels by an index for connected component membership
* PIX *pixConnCompTransform()
*
* Label pixels by the area of their connected component
* PIX *pixConnCompAreaTransform()
*
* Label pixels to allow incremental computation of connected components
* l_int32 pixConnCompIncrInit()
* l_int32 pixConnCompIncrAdd()
* l_int32 pixGetSortedNeighborValues()
*
* Label pixels with spatially-dependent color coding
* PIX *pixLocToColorTransform()
*
* Pixels get labelled in various ways throughout the leptonica library,
* but most of the labelling is implicit, where the new value isn't
* even considered to be a label -- it is just a transformed pixel value
* that may be transformed again by another operation. Quantization
* by thresholding, and dilation by a structuring element, are examples
* of these typical image processing operations.
*
* However, there are some explicit labelling procedures that are useful
* as end-points of analysis, where it typically would not make sense
* to do further image processing on the result. Assigning false color
* based on pixel properties is an example of such labelling operations.
* Such operations typically have 1 bpp input images, and result
* in grayscale or color images.
*
* The procedures in this file are concerned with such explicit labelling.
* Some of these labelling procedures are also in other places in leptonica:
*
* runlength.c:
* This file has two labelling transforms based on runlengths:
* pixStrokeWidthTransform() and pixvRunlengthTransform().
* The pixels are labelled based on the width of the "stroke" to
* which they belong, or on the length of the horizontal or
* vertical run in which they are a member. Runlengths can easily
* be filtered using a threshold.
*
* pixafunc2.c:
* This file has an operation, pixaDisplayRandomCmap(), that
* randomly labels pix in a pixa (that are typically found using
* pixConnComp) with up to 256 values, and assigns each value to
* a random colormap color.
*
* seedfill.c:
* This file has pixDistanceFunction(), that labels each pixel with
* its distance from either the foreground or the background.
* </pre>
*/
#include <string.h>
#include <math.h>
#include "allheaders.h"
/*-----------------------------------------------------------------------*
* Label pixels by an index for connected component membership *
*-----------------------------------------------------------------------*/
/*!
* \brief pixConnCompTransform()
*
* \param[in] pixs 1 bpp
* \param[in] connect connectivity: 4 or 8
* \param[in] depth of pixd: 8 or 16 bpp; use 0 for auto determination
* \return pixd 8, 16 or 32 bpp, or NULL on error
*
* <pre>
* Notes:
* (1) pixd is 8, 16 or 32 bpp, and the pixel values label the
* fg component, starting with 1. Pixels in the bg are labelled 0.
* (2) If %depth = 0, the depth of pixd is 8 if the number of c.c.
* is less than 254, 16 if the number of c.c is less than 0xfffe,
* and 32 otherwise.
* (3) If %depth = 8, the assigned label for the n-th component is
* 1 + n % 254. We use mod 254 because 0 is uniquely assigned
* to black: e.g., see pixcmapCreateRandom(). Likewise,
* if %depth = 16, the assigned label uses mod(2^16 - 2), and
* if %depth = 32, no mod is taken.
* </pre>
*/
PIX *
pixConnCompTransform(PIX *pixs,
l_int32 connect,
l_int32 depth)
{
l_int32 i, n, index, w, h, xb, yb, wb, hb;
BOXA *boxa;
PIX *pix1, *pix2, *pixd;
PIXA *pixa;
PROCNAME("pixConnCompTransform");
if (!pixs || pixGetDepth(pixs) != 1)
return (PIX *)ERROR_PTR("pixs undefined or not 1 bpp", procName, NULL);
if (connect != 4 && connect != 8)
return (PIX *)ERROR_PTR("connectivity must be 4 or 8", procName, NULL);
if (depth != 0 && depth != 8 && depth != 16 && depth != 32)
return (PIX *)ERROR_PTR("depth must be 0, 8, 16 or 32", procName, NULL);
boxa = pixConnComp(pixs, &pixa, connect);
n = pixaGetCount(pixa);
boxaDestroy(&boxa);
pixGetDimensions(pixs, &w, &h, NULL);
if (depth == 0) {
if (n < 254)
depth = 8;
else if (n < 0xfffe)
depth = 16;
else
depth = 32;
}
pixd = pixCreate(w, h, depth);
pixSetSpp(pixd, 1);
if (n == 0) { /* no fg */
pixaDestroy(&pixa);
return pixd;
}
/* Label each component and blit it in */
for (i = 0; i < n; i++) {
pixaGetBoxGeometry(pixa, i, &xb, &yb, &wb, &hb);
pix1 = pixaGetPix(pixa, i, L_CLONE);
if (depth == 8) {
index = 1 + (i % 254);
pix2 = pixConvert1To8(NULL, pix1, 0, index);
} else if (depth == 16) {
index = 1 + (i % 0xfffe);
pix2 = pixConvert1To16(NULL, pix1, 0, index);
} else { /* depth == 32 */
index = 1 + i;
pix2 = pixConvert1To32(NULL, pix1, 0, index);
}
pixRasterop(pixd, xb, yb, wb, hb, PIX_PAINT, pix2, 0, 0);
pixDestroy(&pix1);
pixDestroy(&pix2);
}
pixaDestroy(&pixa);
return pixd;
}
/*-----------------------------------------------------------------------*
* Label pixels by the area of their connected component *
*-----------------------------------------------------------------------*/
/*!
* \brief pixConnCompAreaTransform()
*
* \param[in] pixs 1 bpp
* \param[in] connect connectivity: 4 or 8
* \return pixd 32 bpp, 1 spp, or NULL on error
*
* <pre>
* Notes:
* (1) The pixel values in pixd label the area of the fg component
* to which the pixel belongs. Pixels in the bg are labelled 0.
* (2) For purposes of visualization, the output can be converted
* to 8 bpp, using pixConvert32To8() or pixMaxDynamicRange().
* </pre>
*/
PIX *
pixConnCompAreaTransform(PIX *pixs,
l_int32 connect)
{
l_int32 i, n, npix, w, h, xb, yb, wb, hb;
l_int32 *tab8;
BOXA *boxa;
PIX *pix1, *pix2, *pixd;
PIXA *pixa;
PROCNAME("pixConnCompAreaTransform");
if (!pixs || pixGetDepth(pixs) != 1)
return (PIX *)ERROR_PTR("pixs undefined or not 1 bpp", procName, NULL);
if (connect != 4 && connect != 8)
return (PIX *)ERROR_PTR("connectivity must be 4 or 8", procName, NULL);
boxa = pixConnComp(pixs, &pixa, connect);
n = pixaGetCount(pixa);
boxaDestroy(&boxa);
pixGetDimensions(pixs, &w, &h, NULL);
pixd = pixCreate(w, h, 32);
pixSetSpp(pixd, 1);
if (n == 0) { /* no fg */
pixaDestroy(&pixa);
return pixd;
}
/* Label each component and blit it in */
tab8 = makePixelSumTab8();
for (i = 0; i < n; i++) {
pixaGetBoxGeometry(pixa, i, &xb, &yb, &wb, &hb);
pix1 = pixaGetPix(pixa, i, L_CLONE);
pixCountPixels(pix1, &npix, tab8);
pix2 = pixConvert1To32(NULL, pix1, 0, npix);
pixRasterop(pixd, xb, yb, wb, hb, PIX_PAINT, pix2, 0, 0);
pixDestroy(&pix1);
pixDestroy(&pix2);
}
pixaDestroy(&pixa);
LEPT_FREE(tab8);
return pixd;
}
/*-------------------------------------------------------------------------*
* Label pixels to allow incremental computation of connected components *
*-------------------------------------------------------------------------*/
/*!
* \brief pixConnCompIncrInit()
*
* \param[in] pixs 1 bpp
* \param[in] conn connectivity: 4 or 8
* \param[out] ppixd 32 bpp, with c.c. labelled
* \param[out] pptaa with pixel locations indexed by c.c.
* \param[out] pncc initial number of c.c.
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) This labels the connected components in a 1 bpp pix, and
* additionally sets up a ptaa that lists the locations of pixels
* in each of the components.
* (2) It can be used to initialize the output image and arrays for
* an application that maintains information about connected
* components incrementally as pixels are added.
* (3) pixs can be empty or have some foreground pixels.
* (4) The connectivity is stored in pixd->special.
* (5) Always initialize with the first pta in ptaa being empty
* and representing the background value (index 0) in the pix.
* </pre>
*/
l_ok
pixConnCompIncrInit(PIX *pixs,
l_int32 conn,
PIX **ppixd,
PTAA **pptaa,
l_int32 *pncc)
{
l_int32 empty, w, h, ncc;
PIX *pixd;
PTA *pta;
PTAA *ptaa;
PROCNAME("pixConnCompIncrInit");
if (ppixd) *ppixd = NULL;
if (pptaa) *pptaa = NULL;
if (pncc) *pncc = 0;
if (!ppixd || !pptaa || !pncc)
return ERROR_INT("&pixd, &ptaa, &ncc not all defined", procName, 1);
if (!pixs || pixGetDepth(pixs) != 1)
return ERROR_INT("pixs undefined or not 1 bpp", procName, 1);
if (conn != 4 && conn != 8)
return ERROR_INT("connectivity must be 4 or 8", procName, 1);
pixGetDimensions(pixs, &w, &h, NULL);
pixZero(pixs, &empty);
if (empty) {
*ppixd = pixCreate(w, h, 32);
pixSetSpp(*ppixd, 1);
pixSetSpecial(*ppixd, conn);
*pptaa = ptaaCreate(0);
pta = ptaCreate(1);
ptaaAddPta(*pptaa, pta, L_INSERT); /* reserve index 0 for background */
return 0;
}
/* Set up the initial labeled image and indexed pixel arrays */
if ((pixd = pixConnCompTransform(pixs, conn, 32)) == NULL)
return ERROR_INT("pixd not made", procName, 1);
pixSetSpecial(pixd, conn);
*ppixd = pixd;
if ((ptaa = ptaaIndexLabeledPixels(pixd, &ncc)) == NULL)
return ERROR_INT("ptaa not made", procName, 1);
*pptaa = ptaa;
*pncc = ncc;
return 0;
}
/*!
* \brief pixConnCompIncrAdd()
*
* \param[in] pixs 32 bpp, with pixels labeled by c.c.
* \param[in] ptaa with each pta of pixel locations indexed by c.c.
* \param[out] pncc number of c.c
* \param[in] x,y location of added pixel
* \param[in] debug 0 for no output; otherwise output whenever
* debug <= nvals, up to debug == 3
* \return -1 if nothing happens; 0 if a pixel is added; 1 on error
*
* <pre>
* Notes:
* (1) This adds a pixel and updates the labeled connected components.
* Before calling this function, initialize the process using
* pixConnCompIncrInit().
* (2) As a result of adding a pixel, one of the following can happen,
* depending on the number of neighbors with non-zero value:
* (a) nothing: the pixel is already a member of a c.c.
* (b) no neighbors: a new component is added, increasing the
* number of c.c.
* (c) one neighbor: the pixel is added to an existing c.c.
* (d) more than one neighbor: the added pixel causes joining of
* two or more c.c., reducing the number of c.c. A maximum
* of 4 c.c. can be joined.
* (3) When two c.c. are joined, the pixels in the larger index are
* relabeled to those of the smaller in pixs, and their locations
* are transferred to the pta with the smaller index in the ptaa.
* The pta corresponding to the larger index is then deleted.
* (4) This is an efficient implementation of a "union-find" operation,
* which supports the generation and merging of disjoint sets
* of pixels. This function can be called about 1.3 million times
* per second.
* </pre>
*/
l_int32
pixConnCompIncrAdd(PIX *pixs,
PTAA *ptaa,
l_int32 *pncc,
l_float32 x,
l_float32 y,
l_int32 debug)
{
l_int32 conn, i, j, w, h, count, nvals, ns, firstindex;
l_uint32 val;
l_int32 *neigh;
PTA *ptas, *ptad;
PROCNAME("pixConnCompIncrAdd");
if (!pixs || pixGetDepth(pixs) != 32)
return ERROR_INT("pixs not defined or not 32 bpp", procName, 1);
if (!ptaa)
return ERROR_INT("ptaa not defined", procName, 1);
if (!pncc)
return ERROR_INT("&ncc not defined", procName, 1);
conn = pixs->special;
if (conn != 4 && conn != 8)
return ERROR_INT("connectivity must be 4 or 8", procName, 1);
pixGetDimensions(pixs, &w, &h, NULL);
if (x < 0 || x >= w)
return ERROR_INT("invalid x pixel location", procName, 1);
if (y < 0 || y >= h)
return ERROR_INT("invalid y pixel location", procName, 1);
pixGetPixel(pixs, x, y, &val);
if (val > 0) /* already belongs to a set */
return -1;
/* Find unique neighbor pixel values in increasing order of value.
* If %nvals > 0, these are returned in the %neigh array, which
* is of size %nvals. Note that the pixel values in each
* connected component are used as the index into the pta
* array of the ptaa, giving the pixel locations. */
pixGetSortedNeighborValues(pixs, x, y, conn, &neigh, &nvals);
/* If there are no neighbors, just add a new component */
if (nvals == 0) {
count = ptaaGetCount(ptaa);
pixSetPixel(pixs, x, y, count);
ptas = ptaCreate(1);
ptaAddPt(ptas, x, y);
ptaaAddPta(ptaa, ptas, L_INSERT);
*pncc += 1;
LEPT_FREE(neigh);
return 0;
}
/* Otherwise, there is at least one neighbor. Add the pixel
* to the first neighbor c.c. */
firstindex = neigh[0];
pixSetPixel(pixs, x, y, firstindex);
ptaaAddPt(ptaa, neigh[0], x, y);
if (nvals == 1) {
if (debug == 1)
fprintf(stderr, "nvals = %d: neigh = (%d)\n", nvals, neigh[0]);
LEPT_FREE(neigh);
return 0;
}
/* If nvals > 1, there are at least 2 neighbors, so this pixel
* joins at least one pair of existing c.c. Join each component
* to the first component in the list, which is the one with
* the smallest integer label. This is done in two steps:
* (a) re-label the pixels in the component to the label of the
* first component, and
* (b) save the pixel locations in the pta for the first component. */
if (nvals == 2) {
if (debug >= 1 && debug <= 2) {
fprintf(stderr, "nvals = %d: neigh = (%d,%d)\n", nvals,
neigh[0], neigh[1]);
}
} else if (nvals == 3) {
if (debug >= 1 && debug <= 3) {
fprintf(stderr, "nvals = %d: neigh = (%d,%d,%d)\n", nvals,
neigh[0], neigh[1], neigh[2]);
}
} else { /* nvals == 4 */
if (debug >= 1 && debug <= 4) {
fprintf(stderr, "nvals = %d: neigh = (%d,%d,%d,%d)\n", nvals,
neigh[0], neigh[1], neigh[2], neigh[3]);
}
}
ptad = ptaaGetPta(ptaa, firstindex, L_CLONE);
for (i = 1; i < nvals; i++) {
ptas = ptaaGetPta(ptaa, neigh[i], L_CLONE);
ns = ptaGetCount(ptas);
for (j = 0; j < ns; j++) { /* relabel pixels */
ptaGetPt(ptas, j, &x, &y);
pixSetPixel(pixs, x, y, firstindex);
}
ptaJoin(ptad, ptas, 0, -1); /* add relabeled pixel locations */
*pncc -= 1;
ptaDestroy(&ptaa->pta[neigh[i]]);
ptaDestroy(&ptas); /* the clone */
}
ptaDestroy(&ptad); /* the clone */
LEPT_FREE(neigh);
return 0;
}
/*!
* \brief pixGetSortedNeighborValues()
*
* \param[in] pixs 8, 16 or 32 bpp, with pixels labeled by c.c.
* \param[in] x, y location of pixel
* \param[in] conn 4 or 8 connected neighbors
* \param[out] pneigh array of integers, to be filled with
* the values of the neighbors, if any
* \param[out] pnvals the number of unique neighbor values found
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) The returned %neigh array is the unique set of neighboring
* pixel values, of size nvals, sorted from smallest to largest.
* The value 0, which represents background pixels that do
* not belong to any set of connected components, is discarded.
* (2) If there are no neighbors, this returns %neigh = NULL; otherwise,
* the caller must free the array.
* (3) For either 4 or 8 connectivity, the maximum number of unique
* neighbor values is 4.
* </pre>
*/
l_ok
pixGetSortedNeighborValues(PIX *pixs,
l_int32 x,
l_int32 y,
l_int32 conn,
l_int32 **pneigh,
l_int32 *pnvals)
{
l_int32 i, npt, index;
l_int32 neigh[4];
l_uint32 val;
l_float32 fx, fy;
L_ASET *aset;
L_ASET_NODE *node;
PTA *pta;
RB_TYPE key;
PROCNAME("pixGetSortedNeighborValues");
if (pneigh) *pneigh = NULL;
if (pnvals) *pnvals = 0;
if (!pneigh || !pnvals)
return ERROR_INT("&neigh and &nvals not both defined", procName, 1);
if (!pixs || pixGetDepth(pixs) < 8)
return ERROR_INT("pixs not defined or depth < 8", procName, 1);
/* Identify the locations of nearest neighbor pixels */
if ((pta = ptaGetNeighborPixLocs(pixs, x, y, conn)) == NULL)
return ERROR_INT("pta of neighbors not made", procName, 1);
/* Find the pixel values and insert into a set as keys */
aset = l_asetCreate(L_UINT_TYPE);
npt = ptaGetCount(pta);
for (i = 0; i < npt; i++) {
ptaGetPt(pta, i, &fx, &fy);
pixGetPixel(pixs, (l_int32)fx, (l_int32)fy, &val);
key.utype = val;
l_asetInsert(aset, key);
}
/* Extract the set keys and put them into the %neigh array.
* Omit the value 0, which indicates the pixel doesn't
* belong to one of the sets of connected components. */
node = l_asetGetFirst(aset);
index = 0;
while (node) {
val = node->key.utype;
if (val > 0)
neigh[index++] = (l_int32)val;
node = l_asetGetNext(node);
}
*pnvals = index;
if (index > 0) {
*pneigh = (l_int32 *)LEPT_CALLOC(index, sizeof(l_int32));
for (i = 0; i < index; i++)
(*pneigh)[i] = neigh[i];
}
ptaDestroy(&pta);
l_asetDestroy(&aset);
return 0;
}
/*-----------------------------------------------------------------------*
* Label pixels with spatially-dependent color coding *
*-----------------------------------------------------------------------*/
/*!
* \brief pixLocToColorTransform()
*
* \param[in] pixs 1 bpp
* \return pixd 32 bpp rgb, or NULL on error
*
* <pre>
* Notes:
* (1) This generates an RGB image where each component value
* is coded depending on the (x.y) location and the size
* of the fg connected component that the pixel in pixs belongs to.
* It is independent of the 4-fold orthogonal orientation, and
* only weakly depends on translations and small angle rotations.
* Background pixels are black.
* (2) Such encodings can be compared between two 1 bpp images
* by performing this transform and calculating the
* "earth-mover" distance on the resulting R,G,B histograms.
* </pre>
*/
PIX *
pixLocToColorTransform(PIX *pixs)
{
l_int32 w, h, w2, h2, wpls, wplr, wplg, wplb, wplcc, i, j, rval, gval, bval;
l_float32 invw2, invh2;
l_uint32 *datas, *datar, *datag, *datab, *datacc;
l_uint32 *lines, *liner, *lineg, *lineb, *linecc;
PIX *pix1, *pixcc, *pixr, *pixg, *pixb, *pixd;
PROCNAME("pixLocToColorTransform");
if (!pixs || pixGetDepth(pixs) != 1)
return (PIX *)ERROR_PTR("pixs undefined or not 1 bpp", procName, NULL);
/* Label each pixel with the area of the c.c. to which it belongs.
* Clip the result to 255 in an 8 bpp pix. This is used for
* the blue component of pixd. */
pixGetDimensions(pixs, &w, &h, NULL);
w2 = w / 2;
h2 = h / 2;
invw2 = 255.0 / (l_float32)w2;
invh2 = 255.0 / (l_float32)h2;
pix1 = pixConnCompAreaTransform(pixs, 8);
pixcc = pixConvert32To8(pix1, L_LS_TWO_BYTES, L_CLIP_TO_FF);
pixDestroy(&pix1);
/* Label the red and green components depending on the location
* of the fg pixels, in a way that is 4-fold rotationally invariant. */
pixr = pixCreate(w, h, 8);
pixg = pixCreate(w, h, 8);
pixb = pixCreate(w, h, 8);
wpls = pixGetWpl(pixs);
wplr = pixGetWpl(pixr);
wplg = pixGetWpl(pixg);
wplb = pixGetWpl(pixb);
wplcc = pixGetWpl(pixcc);
datas = pixGetData(pixs);
datar = pixGetData(pixr);
datag = pixGetData(pixg);
datab = pixGetData(pixb);
datacc = pixGetData(pixcc);
for (i = 0; i < h; i++) {
lines = datas + i * wpls;
liner = datar + i * wplr;
lineg = datag + i * wplg;
lineb = datab + i * wplb;
linecc = datacc+ i * wplcc;
for (j = 0; j < w; j++) {
if (GET_DATA_BIT(lines, j) == 0) continue;
if (w < h) {
rval = invh2 * L_ABS((l_float32)(i - h2));
gval = invw2 * L_ABS((l_float32)(j - w2));
} else {
rval = invw2 * L_ABS((l_float32)(j - w2));
gval = invh2 * L_ABS((l_float32)(i - h2));
}
bval = GET_DATA_BYTE(linecc, j);
SET_DATA_BYTE(liner, j, rval);
SET_DATA_BYTE(lineg, j, gval);
SET_DATA_BYTE(lineb, j, bval);
}
}
pixd = pixCreateRGBImage(pixr, pixg, pixb);
pixDestroy(&pixcc);
pixDestroy(&pixr);
pixDestroy(&pixg);
pixDestroy(&pixb);
return pixd;
}