main(int argc,
char **argv)
{
l_int32 i, ival, n;
l_float32 f, val;
GPLOT *gplot;
NUMA *na1, *na2, *na3;
PIX *pixt;
L_REGPARAMS *rp;
if (regTestSetup(argc, argv, &rp))
return 1;
/* Generate a 1D signal and plot it */
na1 = numaCreate(500);
for (i = 0; i < 500; i++) {
f = 48.3 * sin(0.13 * (l_float32)i);
f += 63.4 * cos(0.21 * (l_float32)i);
numaAddNumber(na1, f);
}
gplot = gplotCreate("/tmp/extrema", GPLOT_PNG, "Extrema test", "x", "y");
gplotAddPlot(gplot, NULL, na1, GPLOT_LINES, "plot 1");
/* Find the local min and max and plot them */
na2 = numaFindExtrema(na1, 38.3);
n = numaGetCount(na2);
na3 = numaCreate(n);
for (i = 0; i < n; i++) {
numaGetIValue(na2, i, &ival);
numaGetFValue(na1, ival, &val);
numaAddNumber(na3, val);
}
gplotAddPlot(gplot, na2, na3, GPLOT_POINTS, "plot 2");
gplotMakeOutput(gplot);
#ifndef _WIN32
sleep(1);
#else
Sleep(1000);
#endif /* _WIN32 */
regTestCheckFile(rp, "/tmp/extrema.png"); /* 0 */
pixt = pixRead("/tmp/extrema.png");
pixDisplayWithTitle(pixt, 100, 100, "Extrema test", rp->display);
pixDestroy(&pixt);
gplotDestroy(&gplot);
numaDestroy(&na1);
numaDestroy(&na2);
numaDestroy(&na3);
return regTestCleanup(rp);
}
/*!
* pixSplitComponentWithProfile()
*
* Input: pixs (1 bpp, exactly one connected component)
* delta (distance used in extrema finding in a numa; typ. 10)
* mindel (minimum required difference between profile minimum
* and profile values +2 and -2 away; typ. 7)
* &pixdebug (<optional return> debug image of splitting)
* Return: boxa (of c.c. after splitting), or null on error
*
* Notes:
* (1) This will split the most obvious cases of touching characters.
* The split points it is searching for are narrow and deep
* minimima in the vertical pixel projection profile, after a
* large vertical closing has been applied to the component.
*/
BOXA *
pixSplitComponentWithProfile(PIX *pixs,
l_int32 delta,
l_int32 mindel,
PIX **ppixdebug)
{
l_int32 w, h, n2, i, firstmin, xmin, xshift;
l_int32 nmin, nleft, nright, nsplit, isplit, ncomp;
l_int32 *array1, *array2;
BOX *box;
BOXA *boxad;
NUMA *na1, *na2, *nasplit;
PIX *pix1, *pixdb;
PROCNAME("pixSplitComponentsWithProfile");
if (ppixdebug) *ppixdebug = NULL;
if (!pixs || pixGetDepth(pixs) != 1)
return (BOXA *)ERROR_PTR("pixa undefined or not 1 bpp", procName, NULL);
pixGetDimensions(pixs, &w, &h, NULL);
/* Closing to consolidate characters vertically */
pix1 = pixCloseSafeBrick(NULL, pixs, 1, 100);
/* Get extrema of column projections */
boxad = boxaCreate(2);
na1 = pixCountPixelsByColumn(pix1); /* w elements */
pixDestroy(&pix1);
na2 = numaFindExtrema(na1, delta);
n2 = numaGetCount(na2);
if (n2 < 3) { /* no split possible */
box = boxCreate(0, 0, w, h);
boxaAddBox(boxad, box, L_INSERT);
numaDestroy(&na1);
numaDestroy(&na2);
return boxad;
}
/* Look for sufficiently deep and narrow minima.
* All minima of of interest must be surrounded by max on each
* side. firstmin is the index of first possible minimum. */
array1 = numaGetIArray(na1);
array2 = numaGetIArray(na2);
if (ppixdebug) numaWriteStream(stderr, na2);
firstmin = (array1[array2[0]] > array1[array2[1]]) ? 1 : 2;
nasplit = numaCreate(n2); /* will hold split locations */
for (i = firstmin; i < n2 - 1; i+= 2) {
xmin = array2[i];
nmin = array1[xmin];
if (xmin + 2 >= w) break; /* no more splits possible */
nleft = array1[xmin - 2];
nright = array1[xmin + 2];
if (ppixdebug) {
fprintf(stderr,
"Splitting: xmin = %d, w = %d; nl = %d, nmin = %d, nr = %d\n",
xmin, w, nleft, nmin, nright);
}
if (nleft - nmin >= mindel && nright - nmin >= mindel) /* split */
numaAddNumber(nasplit, xmin);
}
nsplit = numaGetCount(nasplit);
#if 0
if (ppixdebug && nsplit > 0)
gplotSimple1(na1, GPLOT_X11, "/tmp/splitroot", NULL);
#endif
numaDestroy(&na1);
numaDestroy(&na2);
FREE(array1);
FREE(array2);
if (nsplit == 0) { /* no splitting */
box = boxCreate(0, 0, w, h);
boxaAddBox(boxad, box, L_INSERT);
return boxad;
}
/* Use split points to generate b.b. after splitting */
for (i = 0, xshift = 0; i < nsplit; i++) {
numaGetIValue(nasplit, i, &isplit);
box = boxCreate(xshift, 0, isplit - xshift, h);
boxaAddBox(boxad, box, L_INSERT);
xshift = isplit + 1;
}
box = boxCreate(xshift, 0, w - xshift, h);
boxaAddBox(boxad, box, L_INSERT);
numaDestroy(&nasplit);
if (ppixdebug) {
pixdb = pixConvertTo32(pixs);
ncomp = boxaGetCount(boxad);
for (i = 0; i < ncomp; i++) {
box = boxaGetBox(boxad, i, L_CLONE);
pixRenderBoxBlend(pixdb, box, 1, 255, 0, 0, 0.5);
boxDestroy(&box);
}
*ppixdebug = pixdb;
}
return boxad;
}