third-party/leptonica/src/graymorph.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.
*====================================================================*/
/*
* graymorph.c
*
* Top-level grayscale morphological operations (van Herk / Gil-Werman)
* PIX *pixErodeGray()
* PIX *pixDilateGray()
* PIX *pixOpenGray()
* PIX *pixCloseGray()
*
* Special operations for 1x3, 3x1 and 3x3 Sels (direct)
* PIX *pixErodeGray3()
* static PIX *pixErodeGray3h()
* static PIX *pixErodeGray3v()
* PIX *pixDilateGray3()
* static PIX *pixDilateGray3h()
* static PIX *pixDilateGray3v()
* PIX *pixOpenGray3()
* PIX *pixCloseGray3()
*
* Low-level grayscale morphological operations
* static void dilateGrayLow()
* static void erodeGrayLow()
*
*
* Method: Algorithm by van Herk and Gil and Werman, 1992
*
* Measured speed of the vH/G-W implementation is about 1 output
* pixel per 120 PIII clock cycles, for a horizontal or vertical
* erosion or dilation. The computation time doubles for opening
* or closing, or for a square SE, as expected, and is independent
* of the size of the SE.
*
* A faster implementation can be made directly for brick Sels
* of maximum size 3. We unroll the computation for sets of 8 bytes.
* It needs to be called explicitly; the general functions do not
* default for the size 3 brick Sels.
*
* We use the van Herk/Gil-Werman (vHGW) algorithm, [van Herk,
* Patt. Recog. Let. 13, pp. 517-521, 1992; Gil and Werman,
* IEEE Trans PAMI 15(5), pp. 504-507, 1993.]
* This was the first grayscale morphology
* algorithm to compute dilation and erosion with
* complexity independent of the size of the structuring
* element. It is simple and elegant, and surprising that
* it was discovered as recently as 1992. It works for
* SEs composed of horizontal and/or vertical lines. The
* general case requires finding the Min or Max over an
* arbitrary set of pixels, and this requires a number of
* pixel comparisons equal to the SE "size" at each pixel
* in the image. The vHGW algorithm requires not
* more than 3 comparisons at each point. The algorithm has been
* recently refined by Gil and Kimmel ("Efficient Dilation
* Erosion, Opening and Closing Algorithms", in "Mathematical
* Morphology and its Applications to Image and Signal Processing",
* the proceedings of the International Symposium on Mathematical
* Morphology, Palo Alto, CA, June 2000, Kluwer Academic
* Publishers, pp. 301-310). They bring this number down below
* 1.5 comparisons per output pixel but at a cost of significantly
* increased complexity, so I don't bother with that here.
*
* In brief, the method is as follows. We evaluate the dilation
* in groups of "size" pixels, equal to the size of the SE.
* For horizontal, we start at x = "size"/2 and go
* (w - 2 * ("size"/2))/"size" steps. This means that
* we don't evaluate the first 0.5 * "size" pixels and, worst
* case, the last 1.5 * "size" pixels. Thus we embed the
* image in a larger image with these augmented dimensions, where
* the new border pixels are appropriately initialized (0 for
* dilation; 255 for erosion), and remove the boundary at the end.
* (For vertical, use h instead of w.) Then for each group
* of "size" pixels, we form an array of length 2 * "size" + 1,
* consisting of backward and forward partial maxima (for
* dilation) or minima (for erosion). This represents a
* jumping window computed from the source image, over which
* the SE will slide. The center of the array gets the source
* pixel at the center of the SE. Call this the center pixel
* of the window. Array values to left of center get
* the maxima(minima) of the pixels from the center
* one and going to the left an equal distance. Array
* values to the right of center get the maxima(minima) to
* the pixels from the center one and going to the right
* an equal distance. These are computed sequentially starting
* from the center one. The SE (of length "size") can slide over this
* window (of length 2 * "size + 1) at "size" different places.
* At each place, the maxima(minima) of the values in the window
* that correspond to the end points of the SE give the extremal
* values over that interval, and these are stored at the dest
* pixel corresponding to the SE center. A picture is worth
* at least this many words, so if this isn't clear, see the
* leptonica documentation on grayscale morphology.
*/
#include "allheaders.h"
/* Special static operations for 3x1, 1x3 and 3x3 structuring elements */
static PIX *pixErodeGray3h(PIX *pixs);
static PIX *pixErodeGray3v(PIX *pixs);
static PIX *pixDilateGray3h(PIX *pixs);
static PIX *pixDilateGray3v(PIX *pixs);
/* Low-level gray morphological operations */
static void dilateGrayLow(l_uint32 *datad, l_int32 w, l_int32 h,
l_int32 wpld, l_uint32 *datas, l_int32 wpls,
l_int32 size, l_int32 direction, l_uint8 *buffer,
l_uint8 *maxarray);
static void erodeGrayLow(l_uint32 *datad, l_int32 w, l_int32 h,
l_int32 wpld, l_uint32 *datas, l_int32 wpls,
l_int32 size, l_int32 direction, l_uint8 *buffer,
l_uint8 *minarray);
/*-----------------------------------------------------------------*
* Top-level grayscale morphological operations *
*-----------------------------------------------------------------*/
/*!
* pixErodeGray()
*
* Input: pixs
* hsize (of Sel; must be odd; origin implicitly in center)
* vsize (ditto)
* Return: pixd
*
* Notes:
* (1) Sel is a brick with all elements being hits
* (2) If hsize = vsize = 1, just returns a copy.
*/
PIX *
pixErodeGray(PIX *pixs,
l_int32 hsize,
l_int32 vsize)
{
l_uint8 *buffer, *minarray;
l_int32 w, h, wplb, wplt;
l_int32 leftpix, rightpix, toppix, bottompix, maxsize;
l_uint32 *datab, *datat;
PIX *pixb, *pixt, *pixd;
PROCNAME("pixErodeGray");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (hsize < 1 || vsize < 1)
return (PIX *)ERROR_PTR("hsize or vsize < 1", procName, NULL);
if ((hsize & 1) == 0 ) {
L_WARNING("horiz sel size must be odd; increasing by 1\n", procName);
hsize++;
}
if ((vsize & 1) == 0 ) {
L_WARNING("vert sel size must be odd; increasing by 1\n", procName);
vsize++;
}
if (hsize == 1 && vsize == 1)
return pixCopy(NULL, pixs);
if (vsize == 1) { /* horizontal sel */
leftpix = (hsize + 1) / 2;
rightpix = (3 * hsize + 1) / 2;
toppix = 0;
bottompix = 0;
} else if (hsize == 1) { /* vertical sel */
leftpix = 0;
rightpix = 0;
toppix = (vsize + 1) / 2;
bottompix = (3 * vsize + 1) / 2;
} else {
leftpix = (hsize + 1) / 2;
rightpix = (3 * hsize + 1) / 2;
toppix = (vsize + 1) / 2;
bottompix = (3 * vsize + 1) / 2;
}
if ((pixb = pixAddBorderGeneral(pixs,
leftpix, rightpix, toppix, bottompix, 255)) == NULL)
return (PIX *)ERROR_PTR("pixb not made", procName, NULL);
if ((pixt = pixCreateTemplate(pixb)) == NULL)
return (PIX *)ERROR_PTR("pixt not made", procName, NULL);
pixGetDimensions(pixt, &w, &h, NULL);
datab = pixGetData(pixb);
datat = pixGetData(pixt);
wplb = pixGetWpl(pixb);
wplt = pixGetWpl(pixt);
if ((buffer = (l_uint8 *)CALLOC(L_MAX(w, h), sizeof(l_uint8))) == NULL)
return (PIX *)ERROR_PTR("buffer not made", procName, NULL);
maxsize = L_MAX(hsize, vsize);
if ((minarray = (l_uint8 *)CALLOC(2 * maxsize, sizeof(l_uint8))) == NULL)
return (PIX *)ERROR_PTR("minarray not made", procName, NULL);
if (vsize == 1) {
erodeGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, minarray);
} else if (hsize == 1) {
erodeGrayLow(datat, w, h, wplt, datab, wplb, vsize, L_VERT,
buffer, minarray);
} else {
erodeGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, minarray);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_SET);
erodeGrayLow(datab, w, h, wplb, datat, wplt, vsize, L_VERT,
buffer, minarray);
pixDestroy(&pixt);
pixt = pixClone(pixb);
}
if ((pixd = pixRemoveBorderGeneral(pixt,
leftpix, rightpix, toppix, bottompix)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
FREE(buffer);
FREE(minarray);
pixDestroy(&pixb);
pixDestroy(&pixt);
return pixd;
}
/*!
* pixDilateGray()
*
* Input: pixs
* hsize (of Sel; must be odd; origin implicitly in center)
* vsize (ditto)
* Return: pixd
*
* Notes:
* (1) Sel is a brick with all elements being hits
* (2) If hsize = vsize = 1, just returns a copy.
*/
PIX *
pixDilateGray(PIX *pixs,
l_int32 hsize,
l_int32 vsize)
{
l_uint8 *buffer, *maxarray;
l_int32 w, h, wplb, wplt;
l_int32 leftpix, rightpix, toppix, bottompix, maxsize;
l_uint32 *datab, *datat;
PIX *pixb, *pixt, *pixd;
PROCNAME("pixDilateGray");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (hsize < 1 || vsize < 1)
return (PIX *)ERROR_PTR("hsize or vsize < 1", procName, NULL);
if ((hsize & 1) == 0 ) {
L_WARNING("horiz sel size must be odd; increasing by 1\n", procName);
hsize++;
}
if ((vsize & 1) == 0 ) {
L_WARNING("vert sel size must be odd; increasing by 1\n", procName);
vsize++;
}
if (hsize == 1 && vsize == 1)
return pixCopy(NULL, pixs);
if (vsize == 1) { /* horizontal sel */
leftpix = (hsize + 1) / 2;
rightpix = (3 * hsize + 1) / 2;
toppix = 0;
bottompix = 0;
} else if (hsize == 1) { /* vertical sel */
leftpix = 0;
rightpix = 0;
toppix = (vsize + 1) / 2;
bottompix = (3 * vsize + 1) / 2;
} else {
leftpix = (hsize + 1) / 2;
rightpix = (3 * hsize + 1) / 2;
toppix = (vsize + 1) / 2;
bottompix = (3 * vsize + 1) / 2;
}
if ((pixb = pixAddBorderGeneral(pixs,
leftpix, rightpix, toppix, bottompix, 0)) == NULL)
return (PIX *)ERROR_PTR("pixb not made", procName, NULL);
if ((pixt = pixCreateTemplate(pixb)) == NULL)
return (PIX *)ERROR_PTR("pixt not made", procName, NULL);
pixGetDimensions(pixt, &w, &h, NULL);
datab = pixGetData(pixb);
datat = pixGetData(pixt);
wplb = pixGetWpl(pixb);
wplt = pixGetWpl(pixt);
if ((buffer = (l_uint8 *)CALLOC(L_MAX(w, h), sizeof(l_uint8))) == NULL)
return (PIX *)ERROR_PTR("buffer not made", procName, NULL);
maxsize = L_MAX(hsize, vsize);
if ((maxarray = (l_uint8 *)CALLOC(2 * maxsize, sizeof(l_uint8))) == NULL)
return (PIX *)ERROR_PTR("buffer not made", procName, NULL);
if (vsize == 1) {
dilateGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, maxarray);
} else if (hsize == 1) {
dilateGrayLow(datat, w, h, wplt, datab, wplb, vsize, L_VERT,
buffer, maxarray);
} else {
dilateGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, maxarray);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_CLR);
dilateGrayLow(datab, w, h, wplb, datat, wplt, vsize, L_VERT,
buffer, maxarray);
pixDestroy(&pixt);
pixt = pixClone(pixb);
}
if ((pixd = pixRemoveBorderGeneral(pixt,
leftpix, rightpix, toppix, bottompix)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
FREE(buffer);
FREE(maxarray);
pixDestroy(&pixb);
pixDestroy(&pixt);
return pixd;
}
/*!
* pixOpenGray()
*
* Input: pixs
* hsize (of Sel; must be odd; origin implicitly in center)
* vsize (ditto)
* Return: pixd
*
* Notes:
* (1) Sel is a brick with all elements being hits
* (2) If hsize = vsize = 1, just returns a copy.
*/
PIX *
pixOpenGray(PIX *pixs,
l_int32 hsize,
l_int32 vsize)
{
l_uint8 *buffer;
l_uint8 *array; /* used to find either min or max in interval */
l_int32 w, h, wplb, wplt;
l_int32 leftpix, rightpix, toppix, bottompix, maxsize;
l_uint32 *datab, *datat;
PIX *pixb, *pixt, *pixd;
PROCNAME("pixOpenGray");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (hsize < 1 || vsize < 1)
return (PIX *)ERROR_PTR("hsize or vsize < 1", procName, NULL);
if ((hsize & 1) == 0 ) {
L_WARNING("horiz sel size must be odd; increasing by 1\n", procName);
hsize++;
}
if ((vsize & 1) == 0 ) {
L_WARNING("vert sel size must be odd; increasing by 1\n", procName);
vsize++;
}
if (hsize == 1 && vsize == 1)
return pixCopy(NULL, pixs);
if (vsize == 1) { /* horizontal sel */
leftpix = (hsize + 1) / 2;
rightpix = (3 * hsize + 1) / 2;
toppix = 0;
bottompix = 0;
} else if (hsize == 1) { /* vertical sel */
leftpix = 0;
rightpix = 0;
toppix = (vsize + 1) / 2;
bottompix = (3 * vsize + 1) / 2;
} else {
leftpix = (hsize + 1) / 2;
rightpix = (3 * hsize + 1) / 2;
toppix = (vsize + 1) / 2;
bottompix = (3 * vsize + 1) / 2;
}
if ((pixb = pixAddBorderGeneral(pixs,
leftpix, rightpix, toppix, bottompix, 255)) == NULL)
return (PIX *)ERROR_PTR("pixb not made", procName, NULL);
if ((pixt = pixCreateTemplate(pixb)) == NULL)
return (PIX *)ERROR_PTR("pixt not made", procName, NULL);
pixGetDimensions(pixt, &w, &h, NULL);
datab = pixGetData(pixb);
datat = pixGetData(pixt);
wplb = pixGetWpl(pixb);
wplt = pixGetWpl(pixt);
if ((buffer = (l_uint8 *)CALLOC(L_MAX(w, h), sizeof(l_uint8))) == NULL)
return (PIX *)ERROR_PTR("buffer not made", procName, NULL);
maxsize = L_MAX(hsize, vsize);
if ((array = (l_uint8 *)CALLOC(2 * maxsize, sizeof(l_uint8))) == NULL)
return (PIX *)ERROR_PTR("array not made", procName, NULL);
if (vsize == 1) {
erodeGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, array);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_CLR);
dilateGrayLow(datab, w, h, wplb, datat, wplt, hsize, L_HORIZ,
buffer, array);
}
else if (hsize == 1) {
erodeGrayLow(datat, w, h, wplt, datab, wplb, vsize, L_VERT,
buffer, array);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_CLR);
dilateGrayLow(datab, w, h, wplb, datat, wplt, vsize, L_VERT,
buffer, array);
} else {
erodeGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, array);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_SET);
erodeGrayLow(datab, w, h, wplb, datat, wplt, vsize, L_VERT,
buffer, array);
pixSetOrClearBorder(pixb, leftpix, rightpix, toppix, bottompix,
PIX_CLR);
dilateGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, array);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_CLR);
dilateGrayLow(datab, w, h, wplb, datat, wplt, vsize, L_VERT,
buffer, array);
}
if ((pixd = pixRemoveBorderGeneral(pixb,
leftpix, rightpix, toppix, bottompix)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
FREE(buffer);
FREE(array);
pixDestroy(&pixb);
pixDestroy(&pixt);
return pixd;
}
/*!
* pixCloseGray()
*
* Input: pixs
* hsize (of Sel; must be odd; origin implicitly in center)
* vsize (ditto)
* Return: pixd
*
* Notes:
* (1) Sel is a brick with all elements being hits
* (2) If hsize = vsize = 1, just returns a copy.
*/
PIX *
pixCloseGray(PIX *pixs,
l_int32 hsize,
l_int32 vsize)
{
l_uint8 *buffer;
l_uint8 *array; /* used to find either min or max in interval */
l_int32 w, h, wplb, wplt;
l_int32 leftpix, rightpix, toppix, bottompix, maxsize;
l_uint32 *datab, *datat;
PIX *pixb, *pixt, *pixd;
PROCNAME("pixCloseGray");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (hsize < 1 || vsize < 1)
return (PIX *)ERROR_PTR("hsize or vsize < 1", procName, NULL);
if ((hsize & 1) == 0 ) {
L_WARNING("horiz sel size must be odd; increasing by 1\n", procName);
hsize++;
}
if ((vsize & 1) == 0 ) {
L_WARNING("vert sel size must be odd; increasing by 1\n", procName);
vsize++;
}
if (hsize == 1 && vsize == 1)
return pixCopy(NULL, pixs);
if (vsize == 1) { /* horizontal sel */
leftpix = (hsize + 1) / 2;
rightpix = (3 * hsize + 1) / 2;
toppix = 0;
bottompix = 0;
} else if (hsize == 1) { /* vertical sel */
leftpix = 0;
rightpix = 0;
toppix = (vsize + 1) / 2;
bottompix = (3 * vsize + 1) / 2;
} else {
leftpix = (hsize + 1) / 2;
rightpix = (3 * hsize + 1) / 2;
toppix = (vsize + 1) / 2;
bottompix = (3 * vsize + 1) / 2;
}
if ((pixb = pixAddBorderGeneral(pixs,
leftpix, rightpix, toppix, bottompix, 0)) == NULL)
return (PIX *)ERROR_PTR("pixb not made", procName, NULL);
if ((pixt = pixCreateTemplate(pixb)) == NULL)
return (PIX *)ERROR_PTR("pixt not made", procName, NULL);
pixGetDimensions(pixt, &w, &h, NULL);
datab = pixGetData(pixb);
datat = pixGetData(pixt);
wplb = pixGetWpl(pixb);
wplt = pixGetWpl(pixt);
if ((buffer = (l_uint8 *)CALLOC(L_MAX(w, h), sizeof(l_uint8))) == NULL)
return (PIX *)ERROR_PTR("buffer not made", procName, NULL);
maxsize = L_MAX(hsize, vsize);
if ((array = (l_uint8 *)CALLOC(2 * maxsize, sizeof(l_uint8))) == NULL)
return (PIX *)ERROR_PTR("array not made", procName, NULL);
if (vsize == 1) {
dilateGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, array);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_SET);
erodeGrayLow(datab, w, h, wplb, datat, wplt, hsize, L_HORIZ,
buffer, array);
} else if (hsize == 1) {
dilateGrayLow(datat, w, h, wplt, datab, wplb, vsize, L_VERT,
buffer, array);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_SET);
erodeGrayLow(datab, w, h, wplb, datat, wplt, vsize, L_VERT,
buffer, array);
} else {
dilateGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, array);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_CLR);
dilateGrayLow(datab, w, h, wplb, datat, wplt, vsize, L_VERT,
buffer, array);
pixSetOrClearBorder(pixb, leftpix, rightpix, toppix, bottompix,
PIX_SET);
erodeGrayLow(datat, w, h, wplt, datab, wplb, hsize, L_HORIZ,
buffer, array);
pixSetOrClearBorder(pixt, leftpix, rightpix, toppix, bottompix,
PIX_SET);
erodeGrayLow(datab, w, h, wplb, datat, wplt, vsize, L_VERT,
buffer, array);
}
if ((pixd = pixRemoveBorderGeneral(pixb,
leftpix, rightpix, toppix, bottompix)) == NULL)
return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
FREE(buffer);
FREE(array);
pixDestroy(&pixb);
pixDestroy(&pixt);
return pixd;
}
/*-----------------------------------------------------------------*
* Special operations for 1x3, 3x1 and 3x3 Sels *
*-----------------------------------------------------------------*/
/*!
* pixErodeGray3()
*
* Input: pixs (8 bpp, not cmapped)
* hsize (1 or 3)
* vsize (1 or 3)
* Return: pixd, or null on error
*
* Notes:
* (1) Special case for 1x3, 3x1 or 3x3 brick sel (all hits)
* (2) If hsize = vsize = 1, just returns a copy.
* (3) It would be nice not to add a border, but it is required
* if we want the same results as from the general case.
* We add 4 bytes on the left to speed up the copying, and
* 8 bytes at the right and bottom to allow unrolling of
* the computation of 8 pixels.
*/
PIX *
pixErodeGray3(PIX *pixs,
l_int32 hsize,
l_int32 vsize)
{
PIX *pixt, *pixb, *pixbd, *pixd;
PROCNAME("pixErodeGray3");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pix has colormap", procName, NULL);
if ((hsize != 1 && hsize != 3) ||
(vsize != 1 && vsize != 3))
return (PIX *)ERROR_PTR("invalid size: must be 1 or 3", procName, NULL);
if (hsize == 1 && vsize == 1)
return pixCopy(NULL, pixs);
pixb = pixAddBorderGeneral(pixs, 4, 8, 2, 8, 255);
if (vsize == 1)
pixbd = pixErodeGray3h(pixb);
else if (hsize == 1)
pixbd = pixErodeGray3v(pixb);
else { /* vize == hsize == 3 */
pixt = pixErodeGray3h(pixb);
pixbd = pixErodeGray3v(pixt);
pixDestroy(&pixt);
}
pixd = pixRemoveBorderGeneral(pixbd, 4, 8, 2, 8);
pixDestroy(&pixb);
pixDestroy(&pixbd);
return pixd;
}
/*!
* pixErodeGray3h()
*
* Input: pixs (8 bpp, not cmapped)
* Return: pixd, or null on error
*
* Notes:
* (1) Special case for horizontal 3x1 brick Sel;
* also used as the first step for the 3x3 brick Sel.
*/
static PIX *
pixErodeGray3h(PIX *pixs)
{
l_uint32 *datas, *datad, *lines, *lined;
l_int32 w, h, wpl, i, j;
l_int32 val0, val1, val2, val3, val4, val5, val6, val7, val8, val9, minval;
PIX *pixd;
PROCNAME("pixErodeGray3h");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
pixd = pixCreateTemplateNoInit(pixs);
pixSetBorderVal(pixd, 4, 8, 2, 8, 0); /* only to silence valgrind */
pixGetDimensions(pixs, &w, &h, NULL);
datas = pixGetData(pixs);
datad = pixGetData(pixd);
wpl = pixGetWpl(pixs);
for (i = 0; i < h; i++) {
lines = datas + i * wpl;
lined = datad + i * wpl;
for (j = 1; j < w - 8; j += 8) {
val0 = GET_DATA_BYTE(lines, j - 1);
val1 = GET_DATA_BYTE(lines, j);
val2 = GET_DATA_BYTE(lines, j + 1);
val3 = GET_DATA_BYTE(lines, j + 2);
val4 = GET_DATA_BYTE(lines, j + 3);
val5 = GET_DATA_BYTE(lines, j + 4);
val6 = GET_DATA_BYTE(lines, j + 5);
val7 = GET_DATA_BYTE(lines, j + 6);
val8 = GET_DATA_BYTE(lines, j + 7);
val9 = GET_DATA_BYTE(lines, j + 8);
minval = L_MIN(val1, val2);
SET_DATA_BYTE(lined, j, L_MIN(val0, minval));
SET_DATA_BYTE(lined, j + 1, L_MIN(minval, val3));
minval = L_MIN(val3, val4);
SET_DATA_BYTE(lined, j + 2, L_MIN(val2, minval));
SET_DATA_BYTE(lined, j + 3, L_MIN(minval, val5));
minval = L_MIN(val5, val6);
SET_DATA_BYTE(lined, j + 4, L_MIN(val4, minval));
SET_DATA_BYTE(lined, j + 5, L_MIN(minval, val7));
minval = L_MIN(val7, val8);
SET_DATA_BYTE(lined, j + 6, L_MIN(val6, minval));
SET_DATA_BYTE(lined, j + 7, L_MIN(minval, val9));
}
}
return pixd;
}
/*!
* pixErodeGray3v()
*
* Input: pixs (8 bpp, not cmapped)
* Return: pixd, or null on error
*
* Notes:
* (1) Special case for vertical 1x3 brick Sel;
* also used as the second step for the 3x3 brick Sel.
* (2) Surprisingly, this is faster than setting up the
* lineptrs array and accessing into it; e.g.,
* val4 = GET_DATA_BYTE(lines8[i + 3], j);
*/
static PIX *
pixErodeGray3v(PIX *pixs)
{
l_uint32 *datas, *datad, *linesi, *linedi;
l_int32 w, h, wpl, i, j;
l_int32 val0, val1, val2, val3, val4, val5, val6, val7, val8, val9, minval;
PIX *pixd;
PROCNAME("pixErodeGray3v");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
pixd = pixCreateTemplateNoInit(pixs);
pixGetDimensions(pixs, &w, &h, NULL);
datas = pixGetData(pixs);
datad = pixGetData(pixd);
wpl = pixGetWpl(pixs);
for (j = 0; j < w; j++) {
for (i = 1; i < h - 8; i += 8) {
linesi = datas + i * wpl;
linedi = datad + i * wpl;
val0 = GET_DATA_BYTE(linesi - wpl, j);
val1 = GET_DATA_BYTE(linesi, j);
val2 = GET_DATA_BYTE(linesi + wpl, j);
val3 = GET_DATA_BYTE(linesi + 2 * wpl, j);
val4 = GET_DATA_BYTE(linesi + 3 * wpl, j);
val5 = GET_DATA_BYTE(linesi + 4 * wpl, j);
val6 = GET_DATA_BYTE(linesi + 5 * wpl, j);
val7 = GET_DATA_BYTE(linesi + 6 * wpl, j);
val8 = GET_DATA_BYTE(linesi + 7 * wpl, j);
val9 = GET_DATA_BYTE(linesi + 8 * wpl, j);
minval = L_MIN(val1, val2);
SET_DATA_BYTE(linedi, j, L_MIN(val0, minval));
SET_DATA_BYTE(linedi + wpl, j, L_MIN(minval, val3));
minval = L_MIN(val3, val4);
SET_DATA_BYTE(linedi + 2 * wpl, j, L_MIN(val2, minval));
SET_DATA_BYTE(linedi + 3 * wpl, j, L_MIN(minval, val5));
minval = L_MIN(val5, val6);
SET_DATA_BYTE(linedi + 4 * wpl, j, L_MIN(val4, minval));
SET_DATA_BYTE(linedi + 5 * wpl, j, L_MIN(minval, val7));
minval = L_MIN(val7, val8);
SET_DATA_BYTE(linedi + 6 * wpl, j, L_MIN(val6, minval));
SET_DATA_BYTE(linedi + 7 * wpl, j, L_MIN(minval, val9));
}
}
return pixd;
}
/*!
* pixDilateGray3()
*
* Input: pixs (8 bpp, not cmapped)
* hsize (1 or 3)
* vsize (1 or 3)
* Return: pixd, or null on error
*
* Notes:
* (1) Special case for 1x3, 3x1 or 3x3 brick sel (all hits)
* (2) If hsize = vsize = 1, just returns a copy.
*/
PIX *
pixDilateGray3(PIX *pixs,
l_int32 hsize,
l_int32 vsize)
{
PIX *pixt, *pixb, *pixbd, *pixd;
PROCNAME("pixDilateGray3");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pix has colormap", procName, NULL);
if ((hsize != 1 && hsize != 3) ||
(vsize != 1 && vsize != 3))
return (PIX *)ERROR_PTR("invalid size: must be 1 or 3", procName, NULL);
if (hsize == 1 && vsize == 1)
return pixCopy(NULL, pixs);
pixb = pixAddBorderGeneral(pixs, 4, 8, 2, 8, 0);
if (vsize == 1)
pixbd = pixDilateGray3h(pixb);
else if (hsize == 1)
pixbd = pixDilateGray3v(pixb);
else { /* vize == hsize == 3 */
pixt = pixDilateGray3h(pixb);
pixbd = pixDilateGray3v(pixt);
pixDestroy(&pixt);
}
pixd = pixRemoveBorderGeneral(pixbd, 4, 8, 2, 8);
pixDestroy(&pixb);
pixDestroy(&pixbd);
return pixd;
}
/*!
* pixDilateGray3h()
*
* Input: pixs (8 bpp, not cmapped)
* Return: pixd, or null on error
*
* Notes:
* (1) Special case for horizontal 3x1 brick Sel;
* also used as the first step for the 3x3 brick Sel.
*/
static PIX *
pixDilateGray3h(PIX *pixs)
{
l_uint32 *datas, *datad, *lines, *lined;
l_int32 w, h, wpl, i, j;
l_int32 val0, val1, val2, val3, val4, val5, val6, val7, val8, val9, maxval;
PIX *pixd;
PROCNAME("pixDilateGray3h");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
pixd = pixCreateTemplateNoInit(pixs);
pixSetBorderVal(pixd, 4, 8, 2, 8, 0); /* only to silence valgrind */
pixGetDimensions(pixs, &w, &h, NULL);
datas = pixGetData(pixs);
datad = pixGetData(pixd);
wpl = pixGetWpl(pixs);
for (i = 0; i < h; i++) {
lines = datas + i * wpl;
lined = datad + i * wpl;
for (j = 1; j < w - 8; j += 8) {
val0 = GET_DATA_BYTE(lines, j - 1);
val1 = GET_DATA_BYTE(lines, j);
val2 = GET_DATA_BYTE(lines, j + 1);
val3 = GET_DATA_BYTE(lines, j + 2);
val4 = GET_DATA_BYTE(lines, j + 3);
val5 = GET_DATA_BYTE(lines, j + 4);
val6 = GET_DATA_BYTE(lines, j + 5);
val7 = GET_DATA_BYTE(lines, j + 6);
val8 = GET_DATA_BYTE(lines, j + 7);
val9 = GET_DATA_BYTE(lines, j + 8);
maxval = L_MAX(val1, val2);
SET_DATA_BYTE(lined, j, L_MAX(val0, maxval));
SET_DATA_BYTE(lined, j + 1, L_MAX(maxval, val3));
maxval = L_MAX(val3, val4);
SET_DATA_BYTE(lined, j + 2, L_MAX(val2, maxval));
SET_DATA_BYTE(lined, j + 3, L_MAX(maxval, val5));
maxval = L_MAX(val5, val6);
SET_DATA_BYTE(lined, j + 4, L_MAX(val4, maxval));
SET_DATA_BYTE(lined, j + 5, L_MAX(maxval, val7));
maxval = L_MAX(val7, val8);
SET_DATA_BYTE(lined, j + 6, L_MAX(val6, maxval));
SET_DATA_BYTE(lined, j + 7, L_MAX(maxval, val9));
}
}
return pixd;
}
/*!
* pixDilateGray3v()
*
* Input: pixs (8 bpp, not cmapped)
* Return: pixd, or null on error
*
* Notes:
* (1) Special case for vertical 1x3 brick Sel;
* also used as the second step for the 3x3 brick Sel.
*/
static PIX *
pixDilateGray3v(PIX *pixs)
{
l_uint32 *datas, *datad, *linesi, *linedi;
l_int32 w, h, wpl, i, j;
l_int32 val0, val1, val2, val3, val4, val5, val6, val7, val8, val9, maxval;
PIX *pixd;
PROCNAME("pixDilateGray3v");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
pixd = pixCreateTemplateNoInit(pixs);
pixGetDimensions(pixs, &w, &h, NULL);
datas = pixGetData(pixs);
datad = pixGetData(pixd);
wpl = pixGetWpl(pixs);
for (j = 0; j < w; j++) {
for (i = 1; i < h - 8; i += 8) {
linesi = datas + i * wpl;
linedi = datad + i * wpl;
val0 = GET_DATA_BYTE(linesi - wpl, j);
val1 = GET_DATA_BYTE(linesi, j);
val2 = GET_DATA_BYTE(linesi + wpl, j);
val3 = GET_DATA_BYTE(linesi + 2 * wpl, j);
val4 = GET_DATA_BYTE(linesi + 3 * wpl, j);
val5 = GET_DATA_BYTE(linesi + 4 * wpl, j);
val6 = GET_DATA_BYTE(linesi + 5 * wpl, j);
val7 = GET_DATA_BYTE(linesi + 6 * wpl, j);
val8 = GET_DATA_BYTE(linesi + 7 * wpl, j);
val9 = GET_DATA_BYTE(linesi + 8 * wpl, j);
maxval = L_MAX(val1, val2);
SET_DATA_BYTE(linedi, j, L_MAX(val0, maxval));
SET_DATA_BYTE(linedi + wpl, j, L_MAX(maxval, val3));
maxval = L_MAX(val3, val4);
SET_DATA_BYTE(linedi + 2 * wpl, j, L_MAX(val2, maxval));
SET_DATA_BYTE(linedi + 3 * wpl, j, L_MAX(maxval, val5));
maxval = L_MAX(val5, val6);
SET_DATA_BYTE(linedi + 4 * wpl, j, L_MAX(val4, maxval));
SET_DATA_BYTE(linedi + 5 * wpl, j, L_MAX(maxval, val7));
maxval = L_MAX(val7, val8);
SET_DATA_BYTE(linedi + 6 * wpl, j, L_MAX(val6, maxval));
SET_DATA_BYTE(linedi + 7 * wpl, j, L_MAX(maxval, val9));
}
}
return pixd;
}
/*!
* pixOpenGray3()
*
* Input: pixs (8 bpp, not cmapped)
* hsize (1 or 3)
* vsize (1 or 3)
* Return: pixd, or null on error
*
* Notes:
* (1) Special case for 1x3, 3x1 or 3x3 brick sel (all hits)
* (2) If hsize = vsize = 1, just returns a copy.
* (3) It would be nice not to add a border, but it is required
* to get the same results as for the general case.
*/
PIX *
pixOpenGray3(PIX *pixs,
l_int32 hsize,
l_int32 vsize)
{
PIX *pixt, *pixb, *pixbd, *pixd;
PROCNAME("pixOpenGray3");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pix has colormap", procName, NULL);
if ((hsize != 1 && hsize != 3) ||
(vsize != 1 && vsize != 3))
return (PIX *)ERROR_PTR("invalid size: must be 1 or 3", procName, NULL);
if (hsize == 1 && vsize == 1)
return pixCopy(NULL, pixs);
pixb = pixAddBorderGeneral(pixs, 4, 8, 2, 8, 255); /* set to max */
if (vsize == 1) {
pixt = pixErodeGray3h(pixb);
pixSetBorderVal(pixt, 4, 8, 2, 8, 0); /* set to min */
pixbd = pixDilateGray3h(pixt);
pixDestroy(&pixt);
} else if (hsize == 1) {
pixt = pixErodeGray3v(pixb);
pixSetBorderVal(pixt, 4, 8, 2, 8, 0);
pixbd = pixDilateGray3v(pixt);
pixDestroy(&pixt);
} else { /* vize == hsize == 3 */
pixt = pixErodeGray3h(pixb);
pixbd = pixErodeGray3v(pixt);
pixDestroy(&pixt);
pixSetBorderVal(pixbd, 4, 8, 2, 8, 0);
pixt = pixDilateGray3h(pixbd);
pixDestroy(&pixbd);
pixbd = pixDilateGray3v(pixt);
pixDestroy(&pixt);
}
pixd = pixRemoveBorderGeneral(pixbd, 4, 8, 2, 8);
pixDestroy(&pixb);
pixDestroy(&pixbd);
return pixd;
}
/*!
* pixCloseGray3()
*
* Input: pixs (8 bpp, not cmapped)
* hsize (1 or 3)
* vsize (1 or 3)
* Return: pixd, or null on error
*
* Notes:
* (1) Special case for 1x3, 3x1 or 3x3 brick sel (all hits)
* (2) If hsize = vsize = 1, just returns a copy.
*/
PIX *
pixCloseGray3(PIX *pixs,
l_int32 hsize,
l_int32 vsize)
{
PIX *pixt, *pixb, *pixbd, *pixd;
PROCNAME("pixCloseGray3");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
if (pixGetDepth(pixs) != 8)
return (PIX *)ERROR_PTR("pixs not 8 bpp", procName, NULL);
if (pixGetColormap(pixs))
return (PIX *)ERROR_PTR("pix has colormap", procName, NULL);
if ((hsize != 1 && hsize != 3) ||
(vsize != 1 && vsize != 3))
return (PIX *)ERROR_PTR("invalid size: must be 1 or 3", procName, NULL);
if (hsize == 1 && vsize == 1)
return pixCopy(NULL, pixs);
pixb = pixAddBorderGeneral(pixs, 4, 8, 2, 8, 0); /* set to min */
if (vsize == 1) {
pixt = pixDilateGray3h(pixb);
pixSetBorderVal(pixt, 4, 8, 2, 8, 255); /* set to max */
pixbd = pixErodeGray3h(pixt);
pixDestroy(&pixt);
} else if (hsize == 1) {
pixt = pixDilateGray3v(pixb);
pixSetBorderVal(pixt, 4, 8, 2, 8, 255);
pixbd = pixErodeGray3v(pixt);
pixDestroy(&pixt);
} else { /* vize == hsize == 3 */
pixt = pixDilateGray3h(pixb);
pixbd = pixDilateGray3v(pixt);
pixDestroy(&pixt);
pixSetBorderVal(pixbd, 4, 8, 2, 8, 255);
pixt = pixErodeGray3h(pixbd);
pixDestroy(&pixbd);
pixbd = pixErodeGray3v(pixt);
pixDestroy(&pixt);
}
pixd = pixRemoveBorderGeneral(pixbd, 4, 8, 2, 8);
pixDestroy(&pixb);
pixDestroy(&pixbd);
return pixd;
}
/*-----------------------------------------------------------------*
* Low-level gray morphological operations *
*-----------------------------------------------------------------*/
/*!
* dilateGrayLow()
*
* Input: datad, w, h, wpld (8 bpp image)
* datas, wpls (8 bpp image, of same dimensions)
* size (full length of SEL; restricted to odd numbers)
* direction (L_HORIZ or L_VERT)
* buffer (holds full line or column of src image pixels)
* maxarray (array of dimension 2*size+1)
* Return: void
*
* Notes:
* (1) To eliminate border effects on the actual image, these images
* are prepared with an additional border of dimensions:
* leftpix = 0.5 * size
* rightpix = 1.5 * size
* toppix = 0.5 * size
* bottompix = 1.5 * size
* and we initialize the src border pixels to 0.
* This allows full processing over the actual image; at
* the end the border is removed.
* (2) Uses algorithm of van Herk, Gil and Werman
*/
static void
dilateGrayLow(l_uint32 *datad,
l_int32 w,
l_int32 h,
l_int32 wpld,
l_uint32 *datas,
l_int32 wpls,
l_int32 size,
l_int32 direction,
l_uint8 *buffer,
l_uint8 *maxarray)
{
l_int32 i, j, k;
l_int32 hsize, nsteps, startmax, startx, starty;
l_uint8 maxval;
l_uint32 *lines, *lined;
if (direction == L_HORIZ) {
hsize = size / 2;
nsteps = (w - 2 * hsize) / size;
for (i = 0; i < h; i++) {
lines = datas + i * wpls;
lined = datad + i * wpld;
/* fill buffer with pixels in byte order */
for (j = 0; j < w; j++)
buffer[j] = GET_DATA_BYTE(lines, j);
for (j = 0; j < nsteps; j++) {
/* refill the minarray */
startmax = (j + 1) * size - 1;
maxarray[size - 1] = buffer[startmax];
for (k = 1; k < size; k++) {
maxarray[size - 1 - k] =
L_MAX(maxarray[size - k], buffer[startmax - k]);
maxarray[size - 1 + k] =
L_MAX(maxarray[size + k - 2], buffer[startmax + k]);
}
/* compute dilation values */
startx = hsize + j * size;
SET_DATA_BYTE(lined, startx, maxarray[0]);
SET_DATA_BYTE(lined, startx + size - 1, maxarray[2 * size - 2]);
for (k = 1; k < size - 1; k++) {
maxval = L_MAX(maxarray[k], maxarray[k + size - 1]);
SET_DATA_BYTE(lined, startx + k, maxval);
}
}
}
} else { /* direction == L_VERT */
hsize = size / 2;
nsteps = (h - 2 * hsize) / size;
for (j = 0; j < w; j++) {
/* fill buffer with pixels in byte order */
for (i = 0; i < h; i++) {
lines = datas + i * wpls;
buffer[i] = GET_DATA_BYTE(lines, j);
}
for (i = 0; i < nsteps; i++) {
/* refill the minarray */
startmax = (i + 1) * size - 1;
maxarray[size - 1] = buffer[startmax];
for (k = 1; k < size; k++) {
maxarray[size - 1 - k] =
L_MAX(maxarray[size - k], buffer[startmax - k]);
maxarray[size - 1 + k] =
L_MAX(maxarray[size + k - 2], buffer[startmax + k]);
}
/* compute dilation values */
starty = hsize + i * size;
lined = datad + starty * wpld;
SET_DATA_BYTE(lined, j, maxarray[0]);
SET_DATA_BYTE(lined + (size - 1) * wpld, j,
maxarray[2 * size - 2]);
for (k = 1; k < size - 1; k++) {
maxval = L_MAX(maxarray[k], maxarray[k + size - 1]);
SET_DATA_BYTE(lined + wpld * k, j, maxval);
}
}
}
}
return;
}
/*!
* erodeGrayLow()
*
* Input: datad, w, h, wpld (8 bpp image)
* datas, wpls (8 bpp image, of same dimensions)
* size (full length of SEL; restricted to odd numbers)
* direction (L_HORIZ or L_VERT)
* buffer (holds full line or column of src image pixels)
* minarray (array of dimension 2*size+1)
* Return: void
*
* Notes:
* (1) See notes in dilateGrayLow()
*/
static void
erodeGrayLow(l_uint32 *datad,
l_int32 w,
l_int32 h,
l_int32 wpld,
l_uint32 *datas,
l_int32 wpls,
l_int32 size,
l_int32 direction,
l_uint8 *buffer,
l_uint8 *minarray)
{
l_int32 i, j, k;
l_int32 hsize, nsteps, startmin, startx, starty;
l_uint8 minval;
l_uint32 *lines, *lined;
if (direction == L_HORIZ) {
hsize = size / 2;
nsteps = (w - 2 * hsize) / size;
for (i = 0; i < h; i++) {
lines = datas + i * wpls;
lined = datad + i * wpld;
/* fill buffer with pixels in byte order */
for (j = 0; j < w; j++)
buffer[j] = GET_DATA_BYTE(lines, j);
for (j = 0; j < nsteps; j++) {
/* refill the minarray */
startmin = (j + 1) * size - 1;
minarray[size - 1] = buffer[startmin];
for (k = 1; k < size; k++) {
minarray[size - 1 - k] =
L_MIN(minarray[size - k], buffer[startmin - k]);
minarray[size - 1 + k] =
L_MIN(minarray[size + k - 2], buffer[startmin + k]);
}
/* compute erosion values */
startx = hsize + j * size;
SET_DATA_BYTE(lined, startx, minarray[0]);
SET_DATA_BYTE(lined, startx + size - 1, minarray[2 * size - 2]);
for (k = 1; k < size - 1; k++) {
minval = L_MIN(minarray[k], minarray[k + size - 1]);
SET_DATA_BYTE(lined, startx + k, minval);
}
}
}
} else { /* direction == L_VERT */
hsize = size / 2;
nsteps = (h - 2 * hsize) / size;
for (j = 0; j < w; j++) {
/* fill buffer with pixels in byte order */
for (i = 0; i < h; i++) {
lines = datas + i * wpls;
buffer[i] = GET_DATA_BYTE(lines, j);
}
for (i = 0; i < nsteps; i++) {
/* refill the minarray */
startmin = (i + 1) * size - 1;
minarray[size - 1] = buffer[startmin];
for (k = 1; k < size; k++) {
minarray[size - 1 - k] =
L_MIN(minarray[size - k], buffer[startmin - k]);
minarray[size - 1 + k] =
L_MIN(minarray[size + k - 2], buffer[startmin + k]);
}
/* compute erosion values */
starty = hsize + i * size;
lined = datad + starty * wpld;
SET_DATA_BYTE(lined, j, minarray[0]);
SET_DATA_BYTE(lined + (size - 1) * wpld, j,
minarray[2 * size - 2]);
for (k = 1; k < size - 1; k++) {
minval = L_MIN(minarray[k], minarray[k + size - 1]);
SET_DATA_BYTE(lined + wpld * k, j, minval);
}
}
}
}
return;
}