/*!
* \brief pixDeskewLocal()
*
* \param[in] pixs 1 bpp
* \param[in] nslices the number of horizontal overlapping slices;
* must be larger than 1 and not exceed 20;
* use 0 for default
* \param[in] redsweep sweep reduction factor: 1, 2, 4 or 8;
* use 0 for default value
* \param[in] redsearch search reduction factor: 1, 2, 4 or 8, and
* not larger than redsweep; use 0 for default value
* \param[in] sweeprange half the full range, assumed about 0; in degrees;
* use 0.0 for default value
* \param[in] sweepdelta angle increment of sweep; in degrees;
* use 0.0 for default value
* \param[in] minbsdelta min binary search increment angle; in degrees;
* use 0.0 for default value
* \return pixd, or NULL on error
*
* <pre>
* Notes:
* (1) This function allows deskew of a page whose skew changes
* approximately linearly with vertical position. It uses
* a projective transform that in effect does a differential
* shear about the LHS of the page, and makes all text lines
* horizontal.
* (2) The origin of the keystoning can be either a cheap document
* feeder that rotates the page as it is passed through, or a
* camera image taken from either the left or right side
* of the vertical.
* (3) The image transformation is a projective warping,
* not a rotation. Apart from this function, the text lines
* must be properly aligned vertically with respect to each
* other. This can be done by pre-processing the page; e.g.,
* by rotating or horizontally shearing it.
* Typically, this can be achieved by vertically aligning
* the page edge.
* </pre>
*/
PIX *
pixDeskewLocal(PIX *pixs,
l_int32 nslices,
l_int32 redsweep,
l_int32 redsearch,
l_float32 sweeprange,
l_float32 sweepdelta,
l_float32 minbsdelta)
{
l_int32 ret;
PIX *pixd;
PTA *ptas, *ptad;
PROCNAME("pixDeskewLocal");
if (!pixs || pixGetDepth(pixs) != 1)
return (PIX *)ERROR_PTR("pixs undefined or not 1 bpp", procName, NULL);
/* Skew array gives skew angle (deg) as fctn of raster line
* where it intersects the LHS of the image */
ret = pixGetLocalSkewTransform(pixs, nslices, redsweep, redsearch,
sweeprange, sweepdelta, minbsdelta,
&ptas, &ptad);
if (ret != 0)
return (PIX *)ERROR_PTR("transform pts not found", procName, NULL);
/* Use a projective transform */
pixd = pixProjectiveSampledPta(pixs, ptad, ptas, L_BRING_IN_WHITE);
ptaDestroy(&ptas);
ptaDestroy(&ptad);
return pixd;
}
/*!
* pixProjectivePta()
*
* Input: pixs (all depths; colormap ok)
* ptad (4 pts of final coordinate space)
* ptas (4 pts of initial coordinate space)
* incolor (L_BRING_IN_WHITE, L_BRING_IN_BLACK)
* Return: pixd, or null on error
*
* Notes:
* (1) Brings in either black or white pixels from the boundary
* (2) Removes any existing colormap, if necessary, before transforming
*/
PIX *
pixProjectivePta(PIX *pixs,
PTA *ptad,
PTA *ptas,
l_int32 incolor)
{
l_int32 d;
l_uint32 colorval;
PIX *pixt1, *pixt2, *pixd;
PROCNAME("pixProjectivePta");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (!ptas)
return (PIX *)ERROR_PTR("ptas not defined", procName, NULL);
if (!ptad)
return (PIX *)ERROR_PTR("ptad not defined", procName, NULL);
if (incolor != L_BRING_IN_WHITE && incolor != L_BRING_IN_BLACK)
return (PIX *)ERROR_PTR("invalid incolor", procName, NULL);
if (ptaGetCount(ptas) != 4)
return (PIX *)ERROR_PTR("ptas count not 4", procName, NULL);
if (ptaGetCount(ptad) != 4)
return (PIX *)ERROR_PTR("ptad count not 4", procName, NULL);
if (pixGetDepth(pixs) == 1)
return pixProjectiveSampledPta(pixs, ptad, ptas, incolor);
/* Remove cmap if it exists, and unpack to 8 bpp if necessary */
pixt1 = pixRemoveColormap(pixs, REMOVE_CMAP_BASED_ON_SRC);
d = pixGetDepth(pixt1);
if (d < 8)
pixt2 = pixConvertTo8(pixt1, FALSE);
else
pixt2 = pixClone(pixt1);
d = pixGetDepth(pixt2);
/* Compute actual color to bring in from edges */
colorval = 0;
if (incolor == L_BRING_IN_WHITE) {
if (d == 8)
colorval = 255;
else /* d == 32 */
colorval = 0xffffff00;
}
if (d == 8)
pixd = pixProjectivePtaGray(pixt2, ptad, ptas, colorval);
else /* d == 32 */
pixd = pixProjectivePtaColor(pixt2, ptad, ptas, colorval);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
return pixd;
}
int main(int argc, char* argv[])
{
PIX *pixs, *pixb, *pixt;
int minb;
if (argc < 2) {
USAGE: fprintf(stderr, "Usage: %s </path/to/text-image>\n"
"\t\t[binarize-threshold] [minw:minh:maxw:maxh]\n",
strrchr(argv[0], '/') + 1);
return EINVAL;
}
if (2 < argc) { errno = 0;
minb = strtol(argv[2], NULL, 10);
if (errno < 0) {
fprintf(stderr, "strtol: %s\n", strerror(errno));
goto USAGE;
}
} else minb = 180;
if (!(pixs = pixRead(argv[1]))) ;
if (1 && (pixt = pixBackgroundNormMorph(pixs, NULL, 4, 5, 248))) {
pixDestroy(&pixs); pixs = pixt;
} else
if (0 && (pixt = pixBackgroundNorm(pixs, NULL, NULL,
10, 15, 60, 40, 248, 2, 1))) {
pixDestroy(&pixs); pixs = pixt;
}
if (1 && (pixt = pixFindSkewAndDeskew(pixs, 1, NULL, NULL))) {
pixDestroy(&pixs); pixs = pixt;
} if (0 && pixDisplay(pixs, 0, 0)) ;
if (1) { PTA *ptas, *ptad;
if (!(pixb = pixConvertTo1(pixs, minb))) ;
// pixt = pixDeskewLocal(pixs, 10, 0, 0, 0.0, 0.0, 0.0))
if (!pixGetLocalSkewTransform(pixb,
10, 0, 0, 0.0, 0.0, 0.0, &ptas, &ptad)) {
if ((pixt = pixProjectiveSampledPta(pixs,
ptad, ptas, L_BRING_IN_WHITE))) {
pixDestroy(&pixs); pixs = pixt;
} ptaDestroy(&ptas); ptaDestroy(&ptad);
} pixDestroy(&pixb);
}
if (0 && (pixt = pixGammaTRC(NULL, pixs, 1.0, 30, 180))) {
pixDestroy(&pixs); pixs = pixt;
}
if (!(pixb = pixConvertTo1(pixs, minb))) ;
if (0) { pixDestroy(&pixs); pixs = pixCopy(pixs, pixb); } // XXX:
if (1) {
BOX* box;
int i, n, j, m;
PIX *pixi, *pixl;
BOXA *boxi, *boxl;
int x, y, w, h, wid;
int X = INT_MAX, Y = INT_MAX, W = 0, H;
// XXX: do smaller(or no) pixOpenBrick
if (pixGetRegionsBinary(pixb, &pixi, &pixl, NULL, 0)) ;
boxl = pixConnComp(pixl, NULL, 4);
n = boxaGetCount(boxl);
for (i = 0; i < n; ++i) { BOXA* boxa;
box = boxaGetBox(boxl, i, L_CLONE);
boxGetGeometry(box, &x, &y, &w, &h);
if (w < 30 || h < 30 || w < h || h < (w / 40)) {
boxDestroy(&box); continue;
boxaRemoveBox(boxl, i);
}
if (x < X) X = x; if (y < Y) Y = y; if (W < w) W = w;
pixt = pixClipRectangle(pixb, box, NULL);
boxDestroy(&box);
// XXX: for English
if (0) pixt = pixDilateBrick(pixt, pixt, h >> 1, h >> 1); else
pixt = pixDilateBrick(pixt, pixt, 16 < h ? h >> 4 : 1, h << 1);
if (0 && pixDisplay(pixt, 0, 0)) ;
boxa = pixConnComp(pixt, NULL, 8);
pixDestroy(&pixt);
wid = (h * 3) >> 2;
//boxaShift(boxa, x, y);
m = boxaGetCount(boxa);
for (j = 0; j < m; ++j) {
int x0, y0, w0;
box = boxaGetBox(boxa, j, L_CLONE);
boxGetGeometry(box, &x0, &y0, &w0, NULL);
// merge adjacent 2 or 3 small boxes
if (1 && w0 < wid && (j + 1) < m) {
BOX* boxn; int xn, wn;
boxn = boxaGetBox(boxa, j + 1, L_CLONE);
boxGetGeometry(boxn, &xn, NULL, &wn, NULL);
if ((w0 = xn + wn - x0) < h) {
boxaSparseClearBox(boxa, ++j);
if (w0 < wid && (j + 1) < m) {
boxDestroy(&boxn);
boxn = boxaGetBox(boxa, j + 1, L_CLONE);
boxGetGeometry(boxn, &xn, NULL, &wn, NULL);
if ((wn = xn + wn - x0) < h) {
boxaSparseClearBox(boxa, ++j);
w0 = wn;
}
}
boxSetGeometry(box, -1, -1, w0, -1);
} boxDestroy(&boxn);
}
boxSetGeometry(box, x + x0, y + y0, -1, -1);
boxDestroy(&box);
} boxaSparseCompact(boxa);
if (1 && (pixt = pixDrawBoxa(pixs, boxa, 1, 0xff000000))) {
pixDestroy(&pixs); pixs = pixt;
} boxaDestroy(&boxa);
} H = y + h;
main(int argc,
char **argv)
{
char bufname[256];
l_int32 i, j, w, h, d, x, y, wpls;
l_uint32 *datas, *lines;
l_float32 *vc;
PIX *pixs, *pixsc, *pixb, *pixg, *pixc, *pixcs, *pixd;
PIX *pixt1, *pixt2, *pixt3;
PIXA *pixa;
PTA *ptas, *ptad;
static char mainName[] = "projective_reg";
if (argc != 1)
exit(ERROR_INT(" Syntax: projective_reg", mainName, 1));
if ((pixs = pixRead("feyn.tif")) == NULL)
exit(ERROR_INT("pixs not made", mainName, 1));
pixsc = pixScale(pixs, 0.5, 0.5);
#if ALL
/* Test invertability of sampling */
pixa = pixaCreate(0);
for (i = 0; i < 3; i++) {
pixb = pixAddBorder(pixsc, ADDED_BORDER_PIXELS, 0);
MakePtas(i, &ptas, &ptad);
pixt1 = pixProjectiveSampledPta(pixb, ptad, ptas, L_BRING_IN_WHITE);
pixSaveTiled(pixt1, pixa, 1, 1, 20, 8);
pixt2 = pixProjectiveSampledPta(pixt1, ptas, ptad, L_BRING_IN_WHITE);
pixSaveTiled(pixt2, pixa, 1, 0, 20, 0);
pixd = pixRemoveBorder(pixt2, ADDED_BORDER_PIXELS);
pixXor(pixd, pixd, pixsc);
pixSaveTiled(pixd, pixa, 1, 0, 20, 0);
if (i == 0) pixWrite("/tmp/junksamp.png", pixt1, IFF_PNG);
pixDestroy(&pixb);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixd);
ptaDestroy(&ptas);
ptaDestroy(&ptad);
}
pixt1 = pixaDisplay(pixa, 0, 0);
pixWrite("/tmp/junkproj1.png", pixt1, IFF_PNG);
pixDisplay(pixt1, 100, 300);
pixDestroy(&pixt1);
pixaDestroy(&pixa);
#endif
#if ALL
/* Test invertability of interpolation on grayscale */
pixa = pixaCreate(0);
pixg = pixScaleToGray3(pixs);
for (i = 0; i < 3; i++) {
pixb = pixAddBorder(pixg, ADDED_BORDER_PIXELS / 2, 255);
MakePtas(i, &ptas, &ptad);
pixt1 = pixProjectivePta(pixb, ptad, ptas, L_BRING_IN_WHITE);
pixSaveTiled(pixt1, pixa, 1, 1, 20, 8);
pixt2 = pixProjectivePta(pixt1, ptas, ptad, L_BRING_IN_WHITE);
pixSaveTiled(pixt2, pixa, 1, 0, 20, 0);
pixd = pixRemoveBorder(pixt2, ADDED_BORDER_PIXELS / 2);
pixXor(pixd, pixd, pixg);
pixSaveTiled(pixd, pixa, 1, 0, 20, 0);
if (i == 0) pixWrite("/tmp/junkinterp.png", pixt1, IFF_PNG);
pixDestroy(&pixb);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixd);
ptaDestroy(&ptas);
ptaDestroy(&ptad);
}
pixt1 = pixaDisplay(pixa, 0, 0);
pixWrite("/tmp/junkproj2.png", pixt1, IFF_PNG);
pixDisplay(pixt1, 100, 500);
pixDestroy(&pixt1);
pixaDestroy(&pixa);
pixDestroy(&pixg);
#endif
#if ALL
/* Test invertability of interpolation on color */
pixa = pixaCreate(0);
pixc = pixRead("test24.jpg");
pixcs = pixScale(pixc, 0.3, 0.3);
for (i = 0; i < 5; i++) {
pixb = pixAddBorder(pixcs, ADDED_BORDER_PIXELS, 0xffffff00);
MakePtas(i, &ptas, &ptad);
pixt1 = pixProjectivePta(pixb, ptad, ptas, L_BRING_IN_WHITE);
pixSaveTiled(pixt1, pixa, 1, 1, 20, 32);
pixt2 = pixProjectivePta(pixt1, ptas, ptad, L_BRING_IN_WHITE);
pixSaveTiled(pixt2, pixa, 1, 0, 20, 0);
pixd = pixRemoveBorder(pixt2, ADDED_BORDER_PIXELS);
pixXor(pixd, pixd, pixcs);
pixSaveTiled(pixd, pixa, 1, 0, 20, 0);
pixDestroy(&pixb);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixd);
ptaDestroy(&ptas);
ptaDestroy(&ptad);
}
pixt1 = pixaDisplay(pixa, 0, 0);
pixWrite("/tmp/junkproj3.png", pixt1, IFF_PNG);
pixDisplay(pixt1, 100, 500);
pixDestroy(&pixt1);
pixaDestroy(&pixa);
pixDestroy(&pixc);
pixDestroy(&pixcs);
#endif
#if ALL
/* Comparison between sampling and interpolated */
MakePtas(3, &ptas, &ptad);
pixa = pixaCreate(0);
/* Use sampled transform */
pixt1 = pixProjectiveSampledPta(pixs, ptas, ptad, L_BRING_IN_WHITE);
pixSaveTiled(pixt1, pixa, 2, 1, 20, 8);
/* Use interpolated transforms */
pixt2 = pixProjectivePta(pixs, ptas, ptad, L_BRING_IN_WHITE);
pixSaveTiled(pixt2, pixa, 2, 0, 20, 8);
/* Compare the results */
pixXor(pixt2, pixt2, pixt1);
pixSaveTiled(pixt2, pixa, 2, 0, 20, 8);
pixd = pixaDisplay(pixa, 0, 0);
pixWrite("/tmp/junkproj4.png", pixd, IFF_PNG);
pixDisplay(pixd, 100, 700);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixd);
pixaDestroy(&pixa);
ptaDestroy(&ptas);
ptaDestroy(&ptad);
#endif
#if ALL
/* Get timings */
MakePtas(4, &ptas, &ptad);
pixa = pixaCreate(0);
pixg = pixScaleToGray3(pixs);
startTimer();
pixt1 = pixProjectiveSampledPta(pixg, ptas, ptad, L_BRING_IN_WHITE);
fprintf(stderr, " Time for pixProjectiveSampledPta(): %6.2f sec\n", stopTimer());
pixSaveTiled(pixt1, pixa, 1, 1, 20, 8);
startTimer();
pixt2 = pixProjectivePta(pixg, ptas, ptad, L_BRING_IN_WHITE);
fprintf(stderr, " Time for pixProjectivePta(): %6.2f sec\n", stopTimer());
pixSaveTiled(pixt2, pixa, 1, 0, 20, 8);
pixXor(pixt1, pixt1, pixt2);
pixSaveTiled(pixt1, pixa, 1, 0, 20, 8);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixd = pixaDisplay(pixa, 0, 0);
pixWrite("/tmp/junkproj5.png", pixd, IFF_PNG);
pixDisplay(pixd, 100, 900);
pixDestroy(&pixd);
pixDestroy(&pixg);
pixaDestroy(&pixa);
ptaDestroy(&ptas);
ptaDestroy(&ptad);
#endif
pixDestroy(&pixs);
pixDestroy(&pixsc);
return 0;
}
