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twain3.0/3rdparty/hgOCR/leptonica/colorspace.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 colorspace.c
* <pre>
*
* Colorspace conversion between RGB and HSV
* PIX *pixConvertRGBToHSV()
* PIX *pixConvertHSVToRGB()
* l_int32 convertRGBToHSV()
* l_int32 convertHSVToRGB()
* l_int32 pixcmapConvertRGBToHSV()
* l_int32 pixcmapConvertHSVToRGB()
* PIX *pixConvertRGBToHue()
* PIX *pixConvertRGBToSaturation()
* PIX *pixConvertRGBToValue()
*
* Selection and display of range of colors in HSV space
* PIX *pixMakeRangeMaskHS()
* PIX *pixMakeRangeMaskHV()
* PIX *pixMakeRangeMaskSV()
* PIX *pixMakeHistoHS()
* PIX *pixMakeHistoHV()
* PIX *pixMakeHistoSV()
* PIX *pixFindHistoPeaksHSV()
* PIX *displayHSVColorRange()
*
* Colorspace conversion between RGB and YUV
* PIX *pixConvertRGBToYUV()
* PIX *pixConvertYUVToRGB()
* l_int32 convertRGBToYUV()
* l_int32 convertYUVToRGB()
* l_int32 pixcmapConvertRGBToYUV()
* l_int32 pixcmapConvertYUVToRGB()
*
* Colorspace conversion between RGB and XYZ
* FPIXA *pixConvertRGBToXYZ()
* PIX *fpixaConvertXYZToRGB()
* l_int32 convertRGBToXYZ()
* l_int32 convertXYZToRGB()
*
* Colorspace conversion between XYZ and LAB
* FPIXA *fpixaConvertXYZToLAB()
* PIX *fpixaConvertLABToXYZ()
* l_int32 convertXYZToLAB()
* l_int32 convertLABToXYZ()
* static l_float32 lab_forward()
* static l_float32 lab_reverse()
*
* Colorspace conversion between RGB and LAB
* FPIXA *pixConvertRGBToLAB()
* PIX *fpixaConvertLABToRGB()
* l_int32 convertRGBToLAB()
* l_int32 convertLABToRGB()
* </pre>
*/
#include <string.h>
#include <math.h>
#include "allheaders.h"
#ifndef NO_CONSOLE_IO
#define DEBUG_HISTO 0
#define SLOW_CUBE_ROOT 0
#endif /* ~NO_CONSOLE_IO */
/* Functions used in xyz <--> lab conversions */
static l_float32 lab_forward(l_float32 v);
static l_float32 lab_reverse(l_float32 v);
/*---------------------------------------------------------------------------*
* Colorspace conversion between RGB and HSB *
*---------------------------------------------------------------------------*/
/*!
* \brief pixConvertRGBToHSV()
*
* \param[in] pixd can be NULL; if not NULL, must == pixs
* \param[in] pixs
* \return pixd always
*
* <pre>
* Notes:
* (1) For pixs = pixd, this is in-place; otherwise pixd must be NULL.
* (2) The definition of our HSV space is given in convertRGBToHSV().
* (3) The h, s and v values are stored in the same places as
* the r, g and b values, respectively. Here, they are explicitly
* placed in the 3 MS bytes in the pixel.
* (4) Normalizing to 1 and considering the r,g,b components,
* a simple way to understand the HSV space is:
* ~ v = max(r,g,b)
* ~ s = (max - min) / max
* ~ h ~ (mid - min) / (max - min) [apart from signs and constants]
* (5) Normalizing to 1, some properties of the HSV space are:
* ~ For gray values (r = g = b) along the continuum between
* black and white:
* s = 0 (becoming undefined as you approach black)
* h is undefined everywhere
* ~ Where one component is saturated and the others are zero:
* v = 1
* s = 1
* h = 0 (r = max), 1/3 (g = max), 2/3 (b = max)
* ~ Where two components are saturated and the other is zero:
* v = 1
* s = 1
* h = 1/2 (if r = 0), 5/6 (if g = 0), 1/6 (if b = 0)
* </pre>
*/
PIX *
pixConvertRGBToHSV(PIX *pixd,
PIX *pixs)
{
l_int32 w, h, d, wpl, i, j, rval, gval, bval, hval, sval, vval;
l_uint32 *line, *data;
PIXCMAP *cmap;
PROCNAME("pixConvertRGBToHSV");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, pixd);
if (pixd && pixd != pixs)
return (PIX *)ERROR_PTR("pixd defined and not inplace", procName, pixd);
d = pixGetDepth(pixs);
cmap = pixGetColormap(pixs);
if (!cmap && d != 32)
return (PIX *)ERROR_PTR("not cmapped or rgb", procName, pixd);
if (!pixd)
pixd = pixCopy(NULL, pixs);
cmap = pixGetColormap(pixd);
if (cmap) { /* just convert the colormap */
pixcmapConvertRGBToHSV(cmap);
return pixd;
}
/* Convert RGB image */
pixGetDimensions(pixd, &w, &h, NULL);
wpl = pixGetWpl(pixd);
data = pixGetData(pixd);
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
extractRGBValues(line[j], &rval, &gval, &bval);
convertRGBToHSV(rval, gval, bval, &hval, &sval, &vval);
line[j] = (hval << 24) | (sval << 16) | (vval << 8);
}
}
return pixd;
}
/*!
* \brief pixConvertHSVToRGB()
*
* \param[in] pixd can be NULL; if not NULL, must == pixs
* \param[in] pixs
* \return pixd always
*
* <pre>
* Notes:
* (1) For pixs = pixd, this is in-place; otherwise pixd must be NULL.
* (2) The user takes responsibility for making sure that pixs is
* in our HSV space. The definition of our HSV space is given
* in convertRGBToHSV().
* (3) The h, s and v values are stored in the same places as
* the r, g and b values, respectively. Here, they are explicitly
* placed in the 3 MS bytes in the pixel.
* </pre>
*/
PIX *
pixConvertHSVToRGB(PIX *pixd,
PIX *pixs)
{
l_int32 w, h, d, wpl, i, j, rval, gval, bval, hval, sval, vval;
l_uint32 pixel;
l_uint32 *line, *data;
PIXCMAP *cmap;
PROCNAME("pixConvertHSVToRGB");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, pixd);
if (pixd && pixd != pixs)
return (PIX *)ERROR_PTR("pixd defined and not inplace", procName, pixd);
d = pixGetDepth(pixs);
cmap = pixGetColormap(pixs);
if (!cmap && d != 32)
return (PIX *)ERROR_PTR("not cmapped or hsv", procName, pixd);
if (!pixd)
pixd = pixCopy(NULL, pixs);
cmap = pixGetColormap(pixd);
if (cmap) { /* just convert the colormap */
pixcmapConvertHSVToRGB(cmap);
return pixd;
}
/* Convert HSV image */
pixGetDimensions(pixd, &w, &h, NULL);
wpl = pixGetWpl(pixd);
data = pixGetData(pixd);
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
pixel = line[j];
hval = pixel >> 24;
sval = (pixel >> 16) & 0xff;
vval = (pixel >> 8) & 0xff;
convertHSVToRGB(hval, sval, vval, &rval, &gval, &bval);
composeRGBPixel(rval, gval, bval, line + j);
}
}
return pixd;
}
/*!
* \brief convertRGBToHSV()
*
* \param[in] rval, gval, bval RGB input
* \param[out] phval, psval, pvval comparable HSV values
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) The range of returned values is:
* h [0 ... 239]
* s [0 ... 255]
* v [0 ... 255]
* (2) If r = g = b, the pixel is gray (s = 0), and we define h = 0.
* (3) h wraps around, so that h = 0 and h = 240 are equivalent
* in hue space.
* (4) h has the following correspondence to color:
* h = 0 magenta
* h = 40 red
* h = 80 yellow
* h = 120 green
* h = 160 cyan
* h = 200 blue
* </pre>
*/
l_ok
convertRGBToHSV(l_int32 rval,
l_int32 gval,
l_int32 bval,
l_int32 *phval,
l_int32 *psval,
l_int32 *pvval)
{
l_int32 minrg, maxrg, min, max, delta;
l_float32 h;
PROCNAME("convertRGBToHSV");
if (phval) *phval = 0;
if (psval) *psval = 0;
if (pvval) *pvval = 0;
if (!phval || !psval || !pvval)
return ERROR_INT("&hval, &sval, &vval not all defined", procName, 1);
minrg = L_MIN(rval, gval);
min = L_MIN(minrg, bval);
maxrg = L_MAX(rval, gval);
max = L_MAX(maxrg, bval);
delta = max - min;
*pvval = max;
if (delta == 0) { /* gray; no chroma */
*phval = 0;
*psval = 0;
} else {
*psval = (l_int32)(255. * (l_float32)delta / (l_float32)max + 0.5);
if (rval == max) /* between magenta and yellow */
h = (l_float32)(gval - bval) / (l_float32)delta;
else if (gval == max) /* between yellow and cyan */
h = 2. + (l_float32)(bval - rval) / (l_float32)delta;
else /* between cyan and magenta */
h = 4. + (l_float32)(rval - gval) / (l_float32)delta;
h *= 40.0;
if (h < 0.0)
h += 240.0;
if (h >= 239.5)
h = 0.0;
*phval = (l_int32)(h + 0.5);
}
return 0;
}
/*!
* \brief convertHSVToRGB()
*
* \param[in] hval, sval, vval HSV input
* \param[out] prval, pgval, pbval comparable RGB values
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) See convertRGBToHSV() for valid input range of HSV values
* and their interpretation in color space.
* </pre>
*/
l_ok
convertHSVToRGB(l_int32 hval,
l_int32 sval,
l_int32 vval,
l_int32 *prval,
l_int32 *pgval,
l_int32 *pbval)
{
l_int32 i, x, y, z;
l_float32 h, f, s;
PROCNAME("convertHSVToRGB");
if (prval) *prval = 0;
if (pgval) *pgval = 0;
if (pbval) *pbval = 0;
if (!prval || !pgval || !pbval)
return ERROR_INT("&rval, &gval, &bval not all defined", procName, 1);
if (sval == 0) { /* gray */
*prval = vval;
*pgval = vval;
*pbval = vval;
} else {
if (hval < 0 || hval > 240)
return ERROR_INT("invalid hval", procName, 1);
if (hval == 240)
hval = 0;
h = (l_float32)hval / 40.;
i = (l_int32)h;
f = h - i;
s = (l_float32)sval / 255.;
x = (l_int32)(vval * (1. - s) + 0.5);
y = (l_int32)(vval * (1. - s * f) + 0.5);
z = (l_int32)(vval * (1. - s * (1. - f)) + 0.5);
switch (i)
{
case 0:
*prval = vval;
*pgval = z;
*pbval = x;
break;
case 1:
*prval = y;
*pgval = vval;
*pbval = x;
break;
case 2:
*prval = x;
*pgval = vval;
*pbval = z;
break;
case 3:
*prval = x;
*pgval = y;
*pbval = vval;
break;
case 4:
*prval = z;
*pgval = x;
*pbval = vval;
break;
case 5:
*prval = vval;
*pgval = x;
*pbval = y;
break;
default: /* none possible */
return 1;
}
}
return 0;
}
/*!
* \brief pixcmapConvertRGBToHSV()
*
* \param[in] cmap
* \return 0 if OK; 1 on error
*
* <pre>
* Notes:
* ~ in-place transform
* ~ See convertRGBToHSV() for def'n of HSV space.
* ~ replaces: r --> h, g --> s, b --> v
* </pre>
*/
l_ok
pixcmapConvertRGBToHSV(PIXCMAP *cmap)
{
l_int32 i, ncolors, rval, gval, bval, hval, sval, vval;
PROCNAME("pixcmapConvertRGBToHSV");
if (!cmap)
return ERROR_INT("cmap not defined", procName, 1);
ncolors = pixcmapGetCount(cmap);
for (i = 0; i < ncolors; i++) {
pixcmapGetColor(cmap, i, &rval, &gval, &bval);
convertRGBToHSV(rval, gval, bval, &hval, &sval, &vval);
pixcmapResetColor(cmap, i, hval, sval, vval);
}
return 0;
}
/*!
* \brief pixcmapConvertHSVToRGB()
*
* \param[in] cmap
* \return 0 if OK; 1 on error
*
* <pre>
* Notes:
* ~ in-place transform
* ~ See convertRGBToHSV() for def'n of HSV space.
* ~ replaces: h --> r, s --> g, v --> b
* </pre>
*/
l_ok
pixcmapConvertHSVToRGB(PIXCMAP *cmap)
{
l_int32 i, ncolors, rval, gval, bval, hval, sval, vval;
PROCNAME("pixcmapConvertHSVToRGB");
if (!cmap)
return ERROR_INT("cmap not defined", procName, 1);
ncolors = pixcmapGetCount(cmap);
for (i = 0; i < ncolors; i++) {
pixcmapGetColor(cmap, i, &hval, &sval, &vval);
convertHSVToRGB(hval, sval, vval, &rval, &gval, &bval);
pixcmapResetColor(cmap, i, rval, gval, bval);
}
return 0;
}
/*!
* \brief pixConvertRGBToHue()
*
* \param[in] pixs 32 bpp RGB, or 8 bpp with colormap
* \return pixd 8 bpp hue of HSV, or NULL on error
*
* <pre>
* Notes:
* (1) The conversion to HSV hue is in-lined here.
* (2) If there is a colormap, it is removed.
* (3) If you just want the hue component, this does it
* at about 10 Mpixels/sec/GHz, which is about
* 2x faster than using pixConvertRGBToHSV()
* </pre>
*/
PIX *
pixConvertRGBToHue(PIX *pixs)
{
l_int32 w, h, d, wplt, wpld;
l_int32 i, j, rval, gval, bval, hval, minrg, min, maxrg, max, delta;
l_float32 fh;
l_uint32 pixel;
l_uint32 *linet, *lined, *datat, *datad;
PIX *pixt, *pixd;
PROCNAME("pixConvertRGBToHue");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 32 && !pixGetColormap(pixs))
return (PIX *)ERROR_PTR("not cmapped or rgb", procName, NULL);
pixt = pixRemoveColormap(pixs, REMOVE_CMAP_TO_FULL_COLOR);
/* Convert RGB image */
pixd = pixCreate(w, h, 8);
pixCopyResolution(pixd, pixs);
wplt = pixGetWpl(pixt);
datat = pixGetData(pixt);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
for (i = 0; i < h; i++) {
linet = datat + i * wplt;
lined = datad + i * wpld;
for (j = 0; j < w; j++) {
pixel = linet[j];
extractRGBValues(pixel, &rval, &gval, &bval);
minrg = L_MIN(rval, gval);
min = L_MIN(minrg, bval);
maxrg = L_MAX(rval, gval);
max = L_MAX(maxrg, bval);
delta = max - min;
if (delta == 0) { /* gray; no chroma */
hval = 0;
} else {
if (rval == max) /* between magenta and yellow */
fh = (l_float32)(gval - bval) / (l_float32)delta;
else if (gval == max) /* between yellow and cyan */
fh = 2. + (l_float32)(bval - rval) / (l_float32)delta;
else /* between cyan and magenta */
fh = 4. + (l_float32)(rval - gval) / (l_float32)delta;
fh *= 40.0;
if (fh < 0.0)
fh += 240.0;
hval = (l_int32)(fh + 0.5);
}
SET_DATA_BYTE(lined, j, hval);
}
}
pixDestroy(&pixt);
return pixd;
}
/*!
* \brief pixConvertRGBToSaturation()
*
* \param[in] pixs 32 bpp RGB, or 8 bpp with colormap
* \return pixd 8 bpp sat of HSV, or NULL on error
*
* <pre>
* Notes:
* (1) The conversion to HSV sat is in-lined here.
* (2) If there is a colormap, it is removed.
* (3) If you just want the saturation component, this does it
* at about 12 Mpixels/sec/GHz.
* </pre>
*/
PIX *
pixConvertRGBToSaturation(PIX *pixs)
{
l_int32 w, h, d, wplt, wpld;
l_int32 i, j, rval, gval, bval, sval, minrg, min, maxrg, max, delta;
l_uint32 pixel;
l_uint32 *linet, *lined, *datat, *datad;
PIX *pixt, *pixd;
PROCNAME("pixConvertRGBToSaturation");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 32 && !pixGetColormap(pixs))
return (PIX *)ERROR_PTR("not cmapped or rgb", procName, NULL);
pixt = pixRemoveColormap(pixs, REMOVE_CMAP_TO_FULL_COLOR);
/* Convert RGB image */
pixd = pixCreate(w, h, 8);
pixCopyResolution(pixd, pixs);
wplt = pixGetWpl(pixt);
datat = pixGetData(pixt);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
for (i = 0; i < h; i++) {
linet = datat + i * wplt;
lined = datad + i * wpld;
for (j = 0; j < w; j++) {
pixel = linet[j];
extractRGBValues(pixel, &rval, &gval, &bval);
minrg = L_MIN(rval, gval);
min = L_MIN(minrg, bval);
maxrg = L_MAX(rval, gval);
max = L_MAX(maxrg, bval);
delta = max - min;
if (delta == 0) /* gray; no chroma */
sval = 0;
else
sval = (l_int32)(255. *
(l_float32)delta / (l_float32)max + 0.5);
SET_DATA_BYTE(lined, j, sval);
}
}
pixDestroy(&pixt);
return pixd;
}
/*!
* \brief pixConvertRGBToValue()
*
* \param[in] pixs 32 bpp RGB,or 8 bpp with colormap
* \return pixd 8 bpp max component intensity of HSV, or NULL on error
*
* <pre>
* Notes:
* (1) The conversion to HSV sat is in-lined here.
* (2) If there is a colormap, it is removed.
* (3) If you just want the value component, this does it
* at about 35 Mpixels/sec/GHz.
* </pre>
*/
PIX *
pixConvertRGBToValue(PIX *pixs)
{
l_int32 w, h, d, wplt, wpld;
l_int32 i, j, rval, gval, bval, maxrg, max;
l_uint32 pixel;
l_uint32 *linet, *lined, *datat, *datad;
PIX *pixt, *pixd;
PROCNAME("pixConvertRGBToValue");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
pixGetDimensions(pixs, &w, &h, &d);
if (d != 32 && !pixGetColormap(pixs))
return (PIX *)ERROR_PTR("not cmapped or rgb", procName, NULL);
pixt = pixRemoveColormap(pixs, REMOVE_CMAP_TO_FULL_COLOR);
/* Convert RGB image */
pixd = pixCreate(w, h, 8);
pixCopyResolution(pixd, pixs);
wplt = pixGetWpl(pixt);
datat = pixGetData(pixt);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
for (i = 0; i < h; i++) {
linet = datat + i * wplt;
lined = datad + i * wpld;
for (j = 0; j < w; j++) {
pixel = linet[j];
extractRGBValues(pixel, &rval, &gval, &bval);
maxrg = L_MAX(rval, gval);
max = L_MAX(maxrg, bval);
SET_DATA_BYTE(lined, j, max);
}
}
pixDestroy(&pixt);
return pixd;
}
/*---------------------------------------------------------------------------*
* Selection and display of range of colors in HSV space *
*---------------------------------------------------------------------------*/
/*!
* \brief pixMakeRangeMaskHS()
*
* \param[in] pixs 32 bpp rgb
* \param[in] huecenter center value of hue range
* \param[in] huehw half-width of hue range
* \param[in] satcenter center value of saturation range
* \param[in] sathw half-width of saturation range
* \param[in] regionflag L_INCLUDE_REGION, L_EXCLUDE_REGION
* \return pixd 1 bpp mask over selected pixels, or NULL on error
*
* <pre>
* Notes:
* (1) The pixels are selected based on the specified ranges of
* hue and saturation. For selection or exclusion, the pixel
* HS component values must be within both ranges. Care must
* be taken in finding the hue range because of wrap-around.
* (2) Use %regionflag == L_INCLUDE_REGION to take only those
* pixels within the rectangular region specified in HS space.
* Use %regionflag == L_EXCLUDE_REGION to take all pixels except
* those within the rectangular region specified in HS space.
* </pre>
*/
PIX *
pixMakeRangeMaskHS(PIX *pixs,
l_int32 huecenter,
l_int32 huehw,
l_int32 satcenter,
l_int32 sathw,
l_int32 regionflag)
{
l_int32 i, j, w, h, wplt, wpld, hstart, hend, sstart, send, hval, sval;
l_int32 *hlut, *slut;
l_uint32 pixel;
l_uint32 *datat, *datad, *linet, *lined;
PIX *pixt, *pixd;
PROCNAME("pixMakeRangeMaskHS");
if (!pixs || pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
if (regionflag != L_INCLUDE_REGION && regionflag != L_EXCLUDE_REGION)
return (PIX *)ERROR_PTR("invalid regionflag", procName, NULL);
/* Set up LUTs for hue and saturation. These have the value 1
* within the specified intervals of hue and saturation. */
hlut = (l_int32 *)LEPT_CALLOC(240, sizeof(l_int32));
slut = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
sstart = L_MAX(0, satcenter - sathw);
send = L_MIN(255, satcenter + sathw);
for (i = sstart; i <= send; i++)
slut[i] = 1;
hstart = (huecenter - huehw + 240) % 240;
hend = (huecenter + huehw + 240) % 240;
if (hstart < hend) {
for (i = hstart; i <= hend; i++)
hlut[i] = 1;
} else { /* wrap */
for (i = hstart; i < 240; i++)
hlut[i] = 1;
for (i = 0; i <= hend; i++)
hlut[i] = 1;
}
/* Generate the mask */
pixt = pixConvertRGBToHSV(NULL, pixs);
pixGetDimensions(pixs, &w, &h, NULL);
pixd = pixCreateNoInit(w, h, 1);
if (regionflag == L_INCLUDE_REGION)
pixClearAll(pixd);
else /* L_EXCLUDE_REGION */
pixSetAll(pixd);
datat = pixGetData(pixt);
datad = pixGetData(pixd);
wplt = pixGetWpl(pixt);
wpld = pixGetWpl(pixd);
for (i = 0; i < h; i++) {
linet = datat + i * wplt;
lined = datad + i * wpld;
for (j = 0; j < w; j++) {
pixel = linet[j];
hval = (pixel >> L_RED_SHIFT) & 0xff;
sval = (pixel >> L_GREEN_SHIFT) & 0xff;
if (hlut[hval] == 1 && slut[sval] == 1) {
if (regionflag == L_INCLUDE_REGION)
SET_DATA_BIT(lined, j);
else /* L_EXCLUDE_REGION */
CLEAR_DATA_BIT(lined, j);
}
}
}
LEPT_FREE(hlut);
LEPT_FREE(slut);
pixDestroy(&pixt);
return pixd;
}
/*!
* \brief pixMakeRangeMaskHV()
*
* \param[in] pixs 32 bpp rgb
* \param[in] huecenter center value of hue range
* \param[in] huehw half-width of hue range
* \param[in] valcenter center value of max intensity range
* \param[in] valhw half-width of max intensity range
* \param[in] regionflag L_INCLUDE_REGION, L_EXCLUDE_REGION
* \return pixd 1 bpp mask over selected pixels, or NULL on error
*
* <pre>
* Notes:
* (1) The pixels are selected based on the specified ranges of
* hue and max intensity values. For selection or exclusion,
* the pixel HV component values must be within both ranges.
* Care must be taken in finding the hue range because of wrap-around.
* (2) Use %regionflag == L_INCLUDE_REGION to take only those
* pixels within the rectangular region specified in HV space.
* Use %regionflag == L_EXCLUDE_REGION to take all pixels except
* those within the rectangular region specified in HV space.
* </pre>
*/
PIX *
pixMakeRangeMaskHV(PIX *pixs,
l_int32 huecenter,
l_int32 huehw,
l_int32 valcenter,
l_int32 valhw,
l_int32 regionflag)
{
l_int32 i, j, w, h, wplt, wpld, hstart, hend, vstart, vend, hval, vval;
l_int32 *hlut, *vlut;
l_uint32 pixel;
l_uint32 *datat, *datad, *linet, *lined;
PIX *pixt, *pixd;
PROCNAME("pixMakeRangeMaskHV");
if (!pixs || pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
if (regionflag != L_INCLUDE_REGION && regionflag != L_EXCLUDE_REGION)
return (PIX *)ERROR_PTR("invalid regionflag", procName, NULL);
/* Set up LUTs for hue and maximum intensity (val). These have
* the value 1 within the specified intervals of hue and value. */
hlut = (l_int32 *)LEPT_CALLOC(240, sizeof(l_int32));
vlut = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
vstart = L_MAX(0, valcenter - valhw);
vend = L_MIN(255, valcenter + valhw);
for (i = vstart; i <= vend; i++)
vlut[i] = 1;
hstart = (huecenter - huehw + 240) % 240;
hend = (huecenter + huehw + 240) % 240;
if (hstart < hend) {
for (i = hstart; i <= hend; i++)
hlut[i] = 1;
} else {
for (i = hstart; i < 240; i++)
hlut[i] = 1;
for (i = 0; i <= hend; i++)
hlut[i] = 1;
}
/* Generate the mask */
pixt = pixConvertRGBToHSV(NULL, pixs);
pixGetDimensions(pixs, &w, &h, NULL);
pixd = pixCreateNoInit(w, h, 1);
if (regionflag == L_INCLUDE_REGION)
pixClearAll(pixd);
else /* L_EXCLUDE_REGION */
pixSetAll(pixd);
datat = pixGetData(pixt);
datad = pixGetData(pixd);
wplt = pixGetWpl(pixt);
wpld = pixGetWpl(pixd);
for (i = 0; i < h; i++) {
linet = datat + i * wplt;
lined = datad + i * wpld;
for (j = 0; j < w; j++) {
pixel = linet[j];
hval = (pixel >> L_RED_SHIFT) & 0xff;
vval = (pixel >> L_BLUE_SHIFT) & 0xff;
if (hlut[hval] == 1 && vlut[vval] == 1) {
if (regionflag == L_INCLUDE_REGION)
SET_DATA_BIT(lined, j);
else /* L_EXCLUDE_REGION */
CLEAR_DATA_BIT(lined, j);
}
}
}
LEPT_FREE(hlut);
LEPT_FREE(vlut);
pixDestroy(&pixt);
return pixd;
}
/*!
* \brief pixMakeRangeMaskSV()
*
* \param[in] pixs 32 bpp rgb
* \param[in] satcenter center value of saturation range
* \param[in] sathw half-width of saturation range
* \param[in] valcenter center value of max intensity range
* \param[in] valhw half-width of max intensity range
* \param[in] regionflag L_INCLUDE_REGION, L_EXCLUDE_REGION
* \return pixd 1 bpp mask over selected pixels, or NULL on error
*
* <pre>
* Notes:
* (1) The pixels are selected based on the specified ranges of
* saturation and max intensity (val). For selection or
* exclusion, the pixel SV component values must be within both ranges.
* (2) Use %regionflag == L_INCLUDE_REGION to take only those
* pixels within the rectangular region specified in SV space.
* Use %regionflag == L_EXCLUDE_REGION to take all pixels except
* those within the rectangular region specified in SV space.
* </pre>
*/
PIX *
pixMakeRangeMaskSV(PIX *pixs,
l_int32 satcenter,
l_int32 sathw,
l_int32 valcenter,
l_int32 valhw,
l_int32 regionflag)
{
l_int32 i, j, w, h, wplt, wpld, sval, vval, sstart, send, vstart, vend;
l_int32 *slut, *vlut;
l_uint32 pixel;
l_uint32 *datat, *datad, *linet, *lined;
PIX *pixt, *pixd;
PROCNAME("pixMakeRangeMaskSV");
if (!pixs || pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
if (regionflag != L_INCLUDE_REGION && regionflag != L_EXCLUDE_REGION)
return (PIX *)ERROR_PTR("invalid regionflag", procName, NULL);
/* Set up LUTs for saturation and max intensity (val).
* These have the value 1 within the specified intervals of
* saturation and max intensity. */
slut = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
vlut = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32));
sstart = L_MAX(0, satcenter - sathw);
send = L_MIN(255, satcenter + sathw);
vstart = L_MAX(0, valcenter - valhw);
vend = L_MIN(255, valcenter + valhw);
for (i = sstart; i <= send; i++)
slut[i] = 1;
for (i = vstart; i <= vend; i++)
vlut[i] = 1;
/* Generate the mask */
pixt = pixConvertRGBToHSV(NULL, pixs);
pixGetDimensions(pixs, &w, &h, NULL);
pixd = pixCreateNoInit(w, h, 1);
if (regionflag == L_INCLUDE_REGION)
pixClearAll(pixd);
else /* L_EXCLUDE_REGION */
pixSetAll(pixd);
datat = pixGetData(pixt);
datad = pixGetData(pixd);
wplt = pixGetWpl(pixt);
wpld = pixGetWpl(pixd);
for (i = 0; i < h; i++) {
linet = datat + i * wplt;
lined = datad + i * wpld;
for (j = 0; j < w; j++) {
pixel = linet[j];
sval = (pixel >> L_GREEN_SHIFT) & 0xff;
vval = (pixel >> L_BLUE_SHIFT) & 0xff;
if (slut[sval] == 1 && vlut[vval] == 1) {
if (regionflag == L_INCLUDE_REGION)
SET_DATA_BIT(lined, j);
else /* L_EXCLUDE_REGION */
CLEAR_DATA_BIT(lined, j);
}
}
}
LEPT_FREE(slut);
LEPT_FREE(vlut);
pixDestroy(&pixt);
return pixd;
}
/*!
* \brief pixMakeHistoHS()
*
* \param[in] pixs HSV colorspace
* \param[in] factor subsampling factor; integer
* \param[out] pnahue [optional] hue histogram
* \param[out] pnasat [optional] saturation histogram
* \return pixd 32 bpp histogram in hue and saturation, or NULL on error
*
* <pre>
* Notes:
* (1) pixs is a 32 bpp image in HSV colorspace; hue is in the "red"
* byte, saturation is in the "green" byte.
* (2) In pixd, hue is displayed vertically; saturation horizontally.
* The dimensions of pixd are w = 256, h = 240, and the depth
* is 32 bpp. The value at each point is simply the number
* of pixels found at that value of hue and saturation.
* </pre>
*/
PIX *
pixMakeHistoHS(PIX *pixs,
l_int32 factor,
NUMA **pnahue,
NUMA **pnasat)
{
l_int32 i, j, w, h, wplt, hval, sval, nd;
l_uint32 pixel;
l_uint32 *datat, *linet;
void **lined32;
NUMA *nahue, *nasat;
PIX *pixt, *pixd;
PROCNAME("pixMakeHistoHS");
if (pnahue) *pnahue = NULL;
if (pnasat) *pnasat = NULL;
if (!pixs || pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
if (pnahue) {
nahue = numaCreate(240);
numaSetCount(nahue, 240);
*pnahue = nahue;
}
if (pnasat) {
nasat = numaCreate(256);
numaSetCount(nasat, 256);
*pnasat = nasat;
}
if (factor <= 1)
pixt = pixClone(pixs);
else
pixt = pixScaleBySampling(pixs, 1.0 / (l_float32)factor,
1.0 / (l_float32)factor);
/* Create the hue-saturation histogram */
pixd = pixCreate(256, 240, 32);
lined32 = pixGetLinePtrs(pixd, NULL);
pixGetDimensions(pixt, &w, &h, NULL);
datat = pixGetData(pixt);
wplt = pixGetWpl(pixt);
for (i = 0; i < h; i++) {
linet = datat + i * wplt;
for (j = 0; j < w; j++) {
pixel = linet[j];
hval = (pixel >> L_RED_SHIFT) & 0xff;
#if DEBUG_HISTO
if (hval > 239) {
fprintf(stderr, "hval = %d for (%d,%d)\n", hval, i, j);
continue;
}
#endif /* DEBUG_HISTO */
sval = (pixel >> L_GREEN_SHIFT) & 0xff;
if (pnahue)
numaShiftValue(nahue, hval, 1.0);
if (pnasat)
numaShiftValue(nasat, sval, 1.0);
nd = GET_DATA_FOUR_BYTES(lined32[hval], sval);
SET_DATA_FOUR_BYTES(lined32[hval], sval, nd + 1);
}
}
LEPT_FREE(lined32);
pixDestroy(&pixt);
return pixd;
}
/*!
* \brief pixMakeHistoHV()
*
* \param[in] pixs HSV colorspace
* \param[in] factor subsampling factor; integer
* \param[out] pnahue [optional] hue histogram
* \param[out] pnaval [optional] max intensity (value) histogram
* \return pixd 32 bpp histogram in hue and value, or NULL on error
*
* <pre>
* Notes:
* (1) %pixs is a 32 bpp image in HSV colorspace; hue is in the "red"
* byte, max intensity ("value") is in the "blue" byte.
* (2) In %pixd, hue is displayed vertically; intensity horizontally.
* The dimensions of %pixd are w = 256, h = 240, and the depth
* is 32 bpp. The value at each point is simply the number
* of pixels found at that value of hue and intensity.
* </pre>
*/
PIX *
pixMakeHistoHV(PIX *pixs,
l_int32 factor,
NUMA **pnahue,
NUMA **pnaval)
{
l_int32 i, j, w, h, wplt, hval, vval, nd;
l_uint32 pixel;
l_uint32 *datat, *linet;
void **lined32;
NUMA *nahue, *naval;
PIX *pixt, *pixd;
PROCNAME("pixMakeHistoHV");
if (pnahue) *pnahue = NULL;
if (pnaval) *pnaval = NULL;
if (!pixs || pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
if (pnahue) {
nahue = numaCreate(240);
numaSetCount(nahue, 240);
*pnahue = nahue;
}
if (pnaval) {
naval = numaCreate(256);
numaSetCount(naval, 256);
*pnaval = naval;
}
if (factor <= 1)
pixt = pixClone(pixs);
else
pixt = pixScaleBySampling(pixs, 1.0 / (l_float32)factor,
1.0 / (l_float32)factor);
/* Create the hue-value histogram */
pixd = pixCreate(256, 240, 32);
lined32 = pixGetLinePtrs(pixd, NULL);
pixGetDimensions(pixt, &w, &h, NULL);
datat = pixGetData(pixt);
wplt = pixGetWpl(pixt);
for (i = 0; i < h; i++) {
linet = datat + i * wplt;
for (j = 0; j < w; j++) {
pixel = linet[j];
hval = (pixel >> L_RED_SHIFT) & 0xff;
vval = (pixel >> L_BLUE_SHIFT) & 0xff;
if (pnahue)
numaShiftValue(nahue, hval, 1.0);
if (pnaval)
numaShiftValue(naval, vval, 1.0);
nd = GET_DATA_FOUR_BYTES(lined32[hval], vval);
SET_DATA_FOUR_BYTES(lined32[hval], vval, nd + 1);
}
}
LEPT_FREE(lined32);
pixDestroy(&pixt);
return pixd;
}
/*!
* \brief pixMakeHistoSV()
*
* \param[in] pixs HSV colorspace
* \param[in] factor subsampling factor; integer
* \param[out] pnasat [optional] sat histogram
* \param[out] pnaval [optional] max intensity (value) histogram
* \return pixd 32 bpp histogram in sat and value, or NULL on error
*
* <pre>
* Notes:
* (1) %pixs is a 32 bpp image in HSV colorspace; sat is in the "green"
* byte, max intensity ("value") is in the "blue" byte.
* (2) In %pixd, sat is displayed vertically; intensity horizontally.
* The dimensions of %pixd are w = 256, h = 256, and the depth
* is 32 bpp. The value at each point is simply the number
* of pixels found at that value of saturation and intensity.
* </pre>
*/
PIX *
pixMakeHistoSV(PIX *pixs,
l_int32 factor,
NUMA **pnasat,
NUMA **pnaval)
{
l_int32 i, j, w, h, wplt, sval, vval, nd;
l_uint32 pixel;
l_uint32 *datat, *linet;
void **lined32;
NUMA *nasat, *naval;
PIX *pixt, *pixd;
PROCNAME("pixMakeHistoSV");
if (pnasat) *pnasat = NULL;
if (pnaval) *pnaval = NULL;
if (!pixs || pixGetDepth(pixs) != 32)
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
if (pnasat) {
nasat = numaCreate(256);
numaSetCount(nasat, 256);
*pnasat = nasat;
}
if (pnaval) {
naval = numaCreate(256);
numaSetCount(naval, 256);
*pnaval = naval;
}
if (factor <= 1)
pixt = pixClone(pixs);
else
pixt = pixScaleBySampling(pixs, 1.0 / (l_float32)factor,
1.0 / (l_float32)factor);
/* Create the hue-value histogram */
pixd = pixCreate(256, 256, 32);
lined32 = pixGetLinePtrs(pixd, NULL);
pixGetDimensions(pixt, &w, &h, NULL);
datat = pixGetData(pixt);
wplt = pixGetWpl(pixt);
for (i = 0; i < h; i++) {
linet = datat + i * wplt;
for (j = 0; j < w; j++) {
pixel = linet[j];
sval = (pixel >> L_GREEN_SHIFT) & 0xff;
vval = (pixel >> L_BLUE_SHIFT) & 0xff;
if (pnasat)
numaShiftValue(nasat, sval, 1.0);
if (pnaval)
numaShiftValue(naval, vval, 1.0);
nd = GET_DATA_FOUR_BYTES(lined32[sval], vval);
SET_DATA_FOUR_BYTES(lined32[sval], vval, nd + 1);
}
}
LEPT_FREE(lined32);
pixDestroy(&pixt);
return pixd;
}
/*!
* \brief pixFindHistoPeaksHSV()
*
* \param[in] pixs 32 bpp; HS, HV or SV histogram; not changed
* \param[in] type L_HS_HISTO, L_HV_HISTO or L_SV_HISTO
* \param[in] width half width of sliding window
* \param[in] height half height of sliding window
* \param[in] npeaks number of peaks to look for
* \param[in] erasefactor ratio of erase window size to sliding window size
* \param[out] ppta locations of max for each integrated peak area
* \param[out] pnatot integrated peak areas
* \param[out] ppixa [optional] pixa for debugging; NULL to skip
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) %pixs is a 32 bpp histogram in a pair of HSV colorspace. It
* should be thought of as a single sample with 32 bps (bits/sample).
* (2) After each peak is found, the peak is erased with a window
* that is centered on the peak and scaled from the sliding
* window by %erasefactor. Typically, %erasefactor is chosen
* to be > 1.0.
* (3) Data for a maximum of %npeaks is returned in %pta and %natot.
* (4) For debugging, after the pixa is returned, display with:
* pixd = pixaDisplayTiledInRows(pixa, 32, 1000, 1.0, 0, 30, 2);
* </pre>
*/
l_ok
pixFindHistoPeaksHSV(PIX *pixs,
l_int32 type,
l_int32 width,
l_int32 height,
l_int32 npeaks,
l_float32 erasefactor,
PTA **ppta,
NUMA **pnatot,
PIXA **ppixa)
{
l_int32 i, xmax, ymax, ewidth, eheight;
l_uint32 maxval;
BOX *box;
NUMA *natot;
PIX *pixh, *pixw, *pix1, *pix2, *pix3;
PTA *pta;
PROCNAME("pixFindHistoPeaksHSV");
if (ppixa) *ppixa = NULL;
if (ppta) *ppta = NULL;
if (pnatot) *pnatot = NULL;
if (!pixs || pixGetDepth(pixs) != 32)
return ERROR_INT("pixs undefined or not 32 bpp", procName, 1);
if (!ppta || !pnatot)
return ERROR_INT("&pta and &natot not both defined", procName, 1);
if (type != L_HS_HISTO && type != L_HV_HISTO && type != L_SV_HISTO)
return ERROR_INT("invalid HSV histo type", procName, 1);
if ((pta = ptaCreate(npeaks)) == NULL)
return ERROR_INT("pta not made", procName, 1);
*ppta = pta;
if ((natot = numaCreate(npeaks)) == NULL)
return ERROR_INT("natot not made", procName, 1);
*pnatot = natot;
*ppta = pta;
if (type == L_SV_HISTO)
pixh = pixAddMirroredBorder(pixs, width + 1, width + 1, height + 1,
height + 1);
else /* type == L_HS_HISTO or type == L_HV_HISTO */
pixh = pixAddMixedBorder(pixs, width + 1, width + 1, height + 1,
height + 1);
/* Get the total count in the sliding window. If the window
* fully covers the peak, this will be the integrated
* volume under the peak. */
pixw = pixWindowedMean(pixh, width, height, 1, 0);
pixDestroy(&pixh);
/* Sequentially identify and erase peaks in the histogram.
* If requested for debugging, save a pixa of the sequence of
* false color histograms. */
if (ppixa)
*ppixa = pixaCreate(0);
for (i = 0; i < npeaks; i++) {
pixGetMaxValueInRect(pixw, NULL, &maxval, &xmax, &ymax);
if (maxval == 0) break;
numaAddNumber(natot, maxval);
ptaAddPt(pta, xmax, ymax);
ewidth = (l_int32)(width * erasefactor);
eheight = (l_int32)(height * erasefactor);
box = boxCreate(xmax - ewidth, ymax - eheight, 2 * ewidth + 1,
2 * eheight + 1);
if (ppixa) {
pix1 = pixMaxDynamicRange(pixw, L_LINEAR_SCALE);
pixaAddPix(*ppixa, pix1, L_INSERT);
pix2 = pixConvertGrayToFalseColor(pix1, 1.0);
pixaAddPix(*ppixa, pix2, L_INSERT);
pix1 = pixMaxDynamicRange(pixw, L_LOG_SCALE);
pix2 = pixConvertGrayToFalseColor(pix1, 1.0);
pixaAddPix(*ppixa, pix2, L_INSERT);
pix3 = pixConvertTo32(pix1);
pixRenderHashBoxArb(pix3, box, 6, 2, L_NEG_SLOPE_LINE,
1, 255, 100, 100);
pixaAddPix(*ppixa, pix3, L_INSERT);
pixDestroy(&pix1);
}
pixClearInRect(pixw, box);
boxDestroy(&box);
if (type == L_HS_HISTO || type == L_HV_HISTO) {
/* clear wraps at bottom and top */
if (ymax - eheight < 0) { /* overlap to bottom */
box = boxCreate(xmax - ewidth, 240 + ymax - eheight,
2 * ewidth + 1, eheight - ymax);
} else if (ymax + eheight > 239) { /* overlap to top */
box = boxCreate(xmax - ewidth, 0, 2 * ewidth + 1,
ymax + eheight - 239);
} else {
box = NULL;
}
if (box) {
pixClearInRect(pixw, box);
boxDestroy(&box);
}
}
}
pixDestroy(&pixw);
return 0;
}
/*!
* \brief displayHSVColorRange()
*
* \param[in] hval hue center value; in range [0 ... 240]
* \param[in] sval saturation center value; in range [0 ... 255]
* \param[in] vval max intensity value; in range [0 ... 255]
* \param[in] huehw half-width of hue range; > 0
* \param[in] sathw half-width of saturation range; > 0
* \param[in] nsamp number of samplings in each half-width in hue and sat
* \param[in] factor linear size of each color square, in pixels; > 3
* \return pixd 32 bpp set of color squares over input range; NULL on error
*
* <pre>
* Notes:
* (1) The total number of color samplings in each of the hue
* and saturation directions is 2 * nsamp + 1.
* </pre>
*/
PIX *
displayHSVColorRange(l_int32 hval,
l_int32 sval,
l_int32 vval,
l_int32 huehw,
l_int32 sathw,
l_int32 nsamp,
l_int32 factor)
{
l_int32 i, j, w, huedelta, satdelta, hue, sat, rval, gval, bval;
PIX *pixt, *pixd;
PROCNAME("displayHSVColorRange");
if (hval < 0 || hval > 240)
return (PIX *)ERROR_PTR("invalid hval", procName, NULL);
if (huehw < 5 || huehw > 120)
return (PIX *)ERROR_PTR("invalid huehw", procName, NULL);
if (sval - sathw < 0 || sval + sathw > 255)
return (PIX *)ERROR_PTR("invalid sval/sathw", procName, NULL);
if (nsamp < 1 || factor < 3)
return (PIX *)ERROR_PTR("invalid nsamp or rep. factor", procName, NULL);
if (vval < 0 || vval > 255)
return (PIX *)ERROR_PTR("invalid vval", procName, NULL);
w = (2 * nsamp + 1);
huedelta = (l_int32)((l_float32)huehw / (l_float32)nsamp);
satdelta = (l_int32)((l_float32)sathw / (l_float32)nsamp);
pixt = pixCreate(w, w, 32);
for (i = 0; i < w; i++) {
hue = hval + huedelta * (i - nsamp);
if (hue < 0) hue += 240;
if (hue >= 240) hue -= 240;
for (j = 0; j < w; j++) {
sat = sval + satdelta * (j - nsamp);
convertHSVToRGB(hue, sat, vval, &rval, &gval, &bval);
pixSetRGBPixel(pixt, j, i, rval, gval, bval);
}
}
pixd = pixExpandReplicate(pixt, factor);
pixDestroy(&pixt);
return pixd;
}
/*---------------------------------------------------------------------------*
* Colorspace conversion between RGB and YUV *
*---------------------------------------------------------------------------*/
/*!
* \brief pixConvertRGBToYUV()
*
* \param[in] pixd can be NULL; if not NULL, must == pixs
* \param[in] pixs
* \return pixd always
*
* <pre>
* Notes:
* (1) For pixs = pixd, this is in-place; otherwise pixd must be NULL.
* (2) The Y, U and V values are stored in the same places as
* the r, g and b values, respectively. Here, they are explicitly
* placed in the 3 MS bytes in the pixel.
* (3) Normalizing to 1 and considering the r,g,b components,
* a simple way to understand the YUV space is:
* ~ Y = weighted sum of (r,g,b)
* ~ U = weighted difference between Y and B
* ~ V = weighted difference between Y and R
* (4) Following video conventions, Y, U and V are in the range:
* Y: [16, 235]
* U: [16, 240]
* V: [16, 240]
* (5) For the coefficients in the transform matrices, see eq. 4 in
* "Frequently Asked Questions about Color" by Charles Poynton,
* //http://user.engineering.uiowa.edu/~aip/Misc/ColorFAQ.html
* </pre>
*/
PIX *
pixConvertRGBToYUV(PIX *pixd,
PIX *pixs)
{
l_int32 w, h, d, wpl, i, j, rval, gval, bval, yval, uval, vval;
l_uint32 *line, *data;
PIXCMAP *cmap;
PROCNAME("pixConvertRGBToYUV");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, pixd);
if (pixd && pixd != pixs)
return (PIX *)ERROR_PTR("pixd defined and not inplace", procName, pixd);
d = pixGetDepth(pixs);
cmap = pixGetColormap(pixs);
if (!cmap && d != 32)
return (PIX *)ERROR_PTR("not cmapped or rgb", procName, pixd);
if (!pixd)
pixd = pixCopy(NULL, pixs);
cmap = pixGetColormap(pixd);
if (cmap) { /* just convert the colormap */
pixcmapConvertRGBToYUV(cmap);
return pixd;
}
/* Convert RGB image */
pixGetDimensions(pixd, &w, &h, NULL);
wpl = pixGetWpl(pixd);
data = pixGetData(pixd);
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
extractRGBValues(line[j], &rval, &gval, &bval);
convertRGBToYUV(rval, gval, bval, &yval, &uval, &vval);
line[j] = (yval << 24) | (uval << 16) | (vval << 8);
}
}
return pixd;
}
/*!
* \brief pixConvertYUVToRGB()
*
* \param[in] pixd can be NULL; if not NULL, must == pixs
* \param[in] pixs
* \return pixd always
*
* <pre>
* Notes:
* (1) For pixs = pixd, this is in-place; otherwise pixd must be NULL.
* (2) The user takes responsibility for making sure that pixs is
* in YUV space.
* (3) The Y, U and V values are stored in the same places as
* the r, g and b values, respectively. Here, they are explicitly
* placed in the 3 MS bytes in the pixel.
* </pre>
*/
PIX *
pixConvertYUVToRGB(PIX *pixd,
PIX *pixs)
{
l_int32 w, h, d, wpl, i, j, rval, gval, bval, yval, uval, vval;
l_uint32 pixel;
l_uint32 *line, *data;
PIXCMAP *cmap;
PROCNAME("pixConvertYUVToRGB");
if (!pixs)
return (PIX *)ERROR_PTR("pixs not defined", procName, pixd);
if (pixd && pixd != pixs)
return (PIX *)ERROR_PTR("pixd defined and not inplace", procName, pixd);
d = pixGetDepth(pixs);
cmap = pixGetColormap(pixs);
if (!cmap && d != 32)
return (PIX *)ERROR_PTR("not cmapped or hsv", procName, pixd);
if (!pixd)
pixd = pixCopy(NULL, pixs);
cmap = pixGetColormap(pixd);
if (cmap) { /* just convert the colormap */
pixcmapConvertYUVToRGB(cmap);
return pixd;
}
/* Convert YUV image */
pixGetDimensions(pixd, &w, &h, NULL);
wpl = pixGetWpl(pixd);
data = pixGetData(pixd);
for (i = 0; i < h; i++) {
line = data + i * wpl;
for (j = 0; j < w; j++) {
pixel = line[j];
yval = pixel >> 24;
uval = (pixel >> 16) & 0xff;
vval = (pixel >> 8) & 0xff;
convertYUVToRGB(yval, uval, vval, &rval, &gval, &bval);
composeRGBPixel(rval, gval, bval, line + j);
}
}
return pixd;
}
/*!
* \brief convertRGBToYUV()
*
* \param[in] rval, gval, bval RGB input
* \param[out] pyval, puval, pvval equivalent YUV values
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) The range of returned values is:
* Y [16 ... 235]
* U [16 ... 240]
* V [16 ... 240]
* </pre>
*/
l_ok
convertRGBToYUV(l_int32 rval,
l_int32 gval,
l_int32 bval,
l_int32 *pyval,
l_int32 *puval,
l_int32 *pvval)
{
l_float32 norm;
PROCNAME("convertRGBToYUV");
if (pyval) *pyval = 0;
if (puval) *puval = 0;
if (pvval) *pvval = 0;
if (!pyval || !puval || !pvval)
return ERROR_INT("&yval, &uval, &vval not all defined", procName, 1);
norm = 1.0 / 256.;
*pyval = (l_int32)(16.0 +
norm * (65.738 * rval + 129.057 * gval + 25.064 * bval) + 0.5);
*puval = (l_int32)(128.0 +
norm * (-37.945 * rval -74.494 * gval + 112.439 * bval) + 0.5);
*pvval = (l_int32)(128.0 +
norm * (112.439 * rval - 94.154 * gval - 18.285 * bval) + 0.5);
return 0;
}
/*!
* \brief convertYUVToRGB()
*
* \param[in] yval, uval, vval YUV input
* \param[out] prval, pgval, pbval equivalent RGB values
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) The range of valid input values is:
* Y [16 ... 235]
* U [16 ... 240]
* V [16 ... 240]
* (2) Conversion of RGB --> YUV --> RGB leaves the image unchanged.
* (3) The YUV gamut is larger than the RBG gamut; many YUV values
* will result in an invalid RGB value. We clip individual
* r,g,b components to the range [0, 255], and do not test input.
* </pre>
*/
l_ok
convertYUVToRGB(l_int32 yval,
l_int32 uval,
l_int32 vval,
l_int32 *prval,
l_int32 *pgval,
l_int32 *pbval)
{
l_int32 rval, gval, bval;
l_float32 norm, ym, um, vm;
PROCNAME("convertYUVToRGB");
if (prval) *prval = 0;
if (pgval) *pgval = 0;
if (pbval) *pbval = 0;
if (!prval || !pgval || !pbval)
return ERROR_INT("&rval, &gval, &bval not all defined", procName, 1);
norm = 1.0 / 256.;
ym = yval - 16.0;
um = uval - 128.0;
vm = vval - 128.0;
rval = (l_int32)(norm * (298.082 * ym + 408.583 * vm) + 0.5);
gval = (l_int32)(norm * (298.082 * ym - 100.291 * um - 208.120 * vm) +
0.5);
bval = (l_int32)(norm * (298.082 * ym + 516.411 * um) + 0.5);
*prval = L_MIN(255, L_MAX(0, rval));
*pgval = L_MIN(255, L_MAX(0, gval));
*pbval = L_MIN(255, L_MAX(0, bval));
return 0;
}
/*!
* \brief pixcmapConvertRGBToYUV()
*
* \param[in] cmap
* \return 0 if OK; 1 on error
*
* <pre>
* Notes:
* ~ in-place transform
* ~ See convertRGBToYUV() for def'n of YUV space.
* ~ replaces: r --> y, g --> u, b --> v
* </pre>
*/
l_ok
pixcmapConvertRGBToYUV(PIXCMAP *cmap)
{
l_int32 i, ncolors, rval, gval, bval, yval, uval, vval;
PROCNAME("pixcmapConvertRGBToYUV");
if (!cmap)
return ERROR_INT("cmap not defined", procName, 1);
ncolors = pixcmapGetCount(cmap);
for (i = 0; i < ncolors; i++) {
pixcmapGetColor(cmap, i, &rval, &gval, &bval);
convertRGBToYUV(rval, gval, bval, &yval, &uval, &vval);
pixcmapResetColor(cmap, i, yval, uval, vval);
}
return 0;
}
/*!
* \brief pixcmapConvertYUVToRGB()
*
* \param[in] cmap
* \return 0 if OK; 1 on error
*
* <pre>
* Notes:
* ~ in-place transform
* ~ See convertRGBToYUV() for def'n of YUV space.
* ~ replaces: y --> r, u --> g, v --> b
* </pre>
*/
l_ok
pixcmapConvertYUVToRGB(PIXCMAP *cmap)
{
l_int32 i, ncolors, rval, gval, bval, yval, uval, vval;
PROCNAME("pixcmapConvertYUVToRGB");
if (!cmap)
return ERROR_INT("cmap not defined", procName, 1);
ncolors = pixcmapGetCount(cmap);
for (i = 0; i < ncolors; i++) {
pixcmapGetColor(cmap, i, &yval, &uval, &vval);
convertYUVToRGB(yval, uval, vval, &rval, &gval, &bval);
pixcmapResetColor(cmap, i, rval, gval, bval);
}
return 0;
}
/*---------------------------------------------------------------------------*
* Colorspace conversion between RGB and XYZ *
*---------------------------------------------------------------------------*/
/*!
* \brief pixConvertRGBToXYZ()
*
* \param[in] pixs 32 bpp rgb
* \return fpixa xyz
*
* <pre>
* Notes:
* (1) The [x,y,z] values are stored as float values in three fpix
* that are returned in a fpixa.
* (2) The XYZ color space was defined in 1931 as a reference model that
* simulates human color perception. When Y is taken as luminance,
* the values of X and Z constitute a color plane representing
* all the hues that can be perceived. This gamut of colors
* is larger than the gamuts that can be displayed or printed.
* For example, although all rgb values map to XYZ, the converse
* is not true.
* (3) The value of the coefficients depends on the illuminant. We use
* coefficients for converting sRGB under D65 (the spectrum from
* a 6500 degree K black body; an approximation to daylight color).
* See, e.g.,
* http://www.cs.rit.edu/~ncs/color/t_convert.html
* For more general information on color transforms, see:
* http://www.brucelindbloom.com/
* http://user.engineering.uiowa.edu/~aip/Misc/ColorFAQ.html
* http://en.wikipedia.org/wiki/CIE_1931_color_space
* </pre>
*/
FPIXA *
pixConvertRGBToXYZ(PIX *pixs)
{
l_int32 w, h, wpls, wpld, i, j, rval, gval, bval;
l_uint32 *lines, *datas;
l_float32 fxval, fyval, fzval;
l_float32 *linex, *liney, *linez, *datax, *datay, *dataz;
FPIX *fpix;
FPIXA *fpixa;
PROCNAME("pixConvertRGBToXYZ");
if (!pixs || pixGetDepth(pixs) != 32)
return (FPIXA *)ERROR_PTR("pixs undefined or not rgb", procName, NULL);
/* Convert RGB image */
pixGetDimensions(pixs, &w, &h, NULL);
fpixa = fpixaCreate(3);
for (i = 0; i < 3; i++) {
fpix = fpixCreate(w, h);
fpixaAddFPix(fpixa, fpix, L_INSERT);
}
wpls = pixGetWpl(pixs);
wpld = fpixGetWpl(fpix);
datas = pixGetData(pixs);
datax = fpixaGetData(fpixa, 0);
datay = fpixaGetData(fpixa, 1);
dataz = fpixaGetData(fpixa, 2);
for (i = 0; i < h; i++) {
lines = datas + i * wpls;
linex = datax + i * wpld;
liney = datay + i * wpld;
linez = dataz + i * wpld;
for (j = 0; j < w; j++) {
extractRGBValues(lines[j], &rval, &gval, &bval);
convertRGBToXYZ(rval, gval, bval, &fxval, &fyval, &fzval);
*(linex + j) = fxval;
*(liney + j) = fyval;
*(linez + j) = fzval;
}
}
return fpixa;
}
/*!
* \brief fpixaConvertXYZToRGB()
*
* \param[in] fpixa three fpix: x,y,z
* \return pixd 32 bpp rgb
*
* <pre>
* Notes:
* (1) The xyz image is stored in three fpix.
* (2) For values of xyz that are out of gamut for rgb, the rgb
* components are set to the closest valid color.
* </pre>
*/
PIX *
fpixaConvertXYZToRGB(FPIXA *fpixa)
{
l_int32 w, h, wpls, wpld, i, j, rval, gval, bval;
l_float32 fxval, fyval, fzval;
l_float32 *linex, *liney, *linez, *datax, *datay, *dataz;
l_uint32 *lined, *datad;
PIX *pixd;
FPIX *fpix;
PROCNAME("fpixaConvertXYZToRGB");
if (!fpixa || fpixaGetCount(fpixa) != 3)
return (PIX *)ERROR_PTR("fpixa undefined or invalid", procName, NULL);
/* Convert XYZ image */
if (fpixaGetFPixDimensions(fpixa, 0, &w, &h))
return (PIX *)ERROR_PTR("fpixa dimensions not found", procName, NULL);
pixd = pixCreate(w, h, 32);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
datax = fpixaGetData(fpixa, 0);
datay = fpixaGetData(fpixa, 1);
dataz = fpixaGetData(fpixa, 2);
fpix = fpixaGetFPix(fpixa, 0, L_CLONE);
wpls = fpixGetWpl(fpix);
fpixDestroy(&fpix);
for (i = 0; i < h; i++) {
linex = datax + i * wpls;
liney = datay + i * wpls;
linez = dataz + i * wpls;
lined = datad + i * wpld;
for (j = 0; j < w; j++) {
fxval = linex[j];
fyval = liney[j];
fzval = linez[j];
convertXYZToRGB(fxval, fyval, fzval, 0, &rval, &gval, &bval);
composeRGBPixel(rval, gval, bval, lined + j);
}
}
return pixd;
}
/*!
* \brief convertRGBToXYZ()
*
* \param[in] rval, gval, bval rgb input
* \param[out] pfxval, pfyval, pfzval equivalent xyz values
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) These conversions are for illuminant D65 acting on linear sRGB
* values.
* </pre>
*/
l_ok
convertRGBToXYZ(l_int32 rval,
l_int32 gval,
l_int32 bval,
l_float32 *pfxval,
l_float32 *pfyval,
l_float32 *pfzval)
{
PROCNAME("convertRGBToXYZ");
if (pfxval) *pfxval = 0.0;
if (pfyval) *pfyval = 0.0;
if (pfzval) *pfzval = 0.0;
if (!pfxval || !pfyval || !pfzval)
return ERROR_INT("&xval, &yval, &zval not all defined", procName, 1);
*pfxval = 0.4125 * rval + 0.3576 * gval + 0.1804 * bval;
*pfyval = 0.2127 * rval + 0.7152 * gval + 0.0722 * bval;
*pfzval = 0.0193 * rval + 0.1192 * gval + 0.9502 * bval;
return 0;
}
/*!
* \brief convertXYZToRGB()
*
* \param[in] fxval, fyval, fzval
* \param[in] blackout 0 to output nearest color if out of gamut;
* 1 to output black
* \param[out] prval, pgval, pbval 32 bpp rgb values
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) For values of xyz that are out of gamut for rgb, at least
* one of the r, g or b components will be either less than 0
* or greater than 255. For that situation:
* * if %blackout == 0, the individual component(s) that are out
* of gamut will be set to 0 or 255, respectively.
* * if %blackout == 1, the output color will be set to black
* </pre>
*/
l_ok
convertXYZToRGB(l_float32 fxval,
l_float32 fyval,
l_float32 fzval,
l_int32 blackout,
l_int32 *prval,
l_int32 *pgval,
l_int32 *pbval)
{
l_int32 rval, gval, bval;
PROCNAME("convertXYZToRGB");
if (prval) *prval = 0;
if (pgval) *pgval = 0;
if (pbval) *pbval = 0;
if (!prval || !pgval ||!pbval)
return ERROR_INT("&rval, &gval, &bval not all defined", procName, 1);
*prval = *pgval = *pbval = 0;
rval = (l_int32)(3.2405 * fxval - 1.5372 * fyval - 0.4985 * fzval + 0.5);
gval = (l_int32)(-0.9693 * fxval + 1.8760 * fyval + 0.0416 * fzval + 0.5);
bval = (l_int32)(0.0556 * fxval - 0.2040 * fyval + 1.0573 * fzval + 0.5);
if (blackout == 0) { /* the usual situation; use nearest rgb color */
*prval = L_MAX(0, L_MIN(rval, 255));
*pgval = L_MAX(0, L_MIN(gval, 255));
*pbval = L_MAX(0, L_MIN(bval, 255));
} else { /* use black for out of gamut */
if (rval >= 0 && rval < 256 && gval >= 0 && gval < 256 &&
bval >= 0 && bval < 256) { /* in gamut */
*prval = rval;
*pgval = gval;
*pbval = bval;
}
}
return 0;
}
/*---------------------------------------------------------------------------*
* Colorspace conversion between XYZ and LAB *
*---------------------------------------------------------------------------*/
/*!
* \brief fpixaConvertXYZToLAB()
*
* \param[in] fpixas xyz
* \return fpixa lab
*
* <pre>
* Notes:
* (1) The input [x,y,z] and output [l,a,b] values are stored as
* float values, each set in three fpix.
* (2) The CIE LAB color space was invented in 1976, as an
* absolute reference for specifying colors that we can
* perceive, independently of the rendering device. It was
* invented to align color display and print images.
* For information, see:
* http://www.brucelindbloom.com/
* http://en.wikipedia.org/wiki/Lab_color_space
* </pre>
*/
FPIXA *
fpixaConvertXYZToLAB(FPIXA *fpixas)
{
l_int32 w, h, wpl, i, j;
l_float32 fxval, fyval, fzval, flval, faval, fbval;
l_float32 *linex, *liney, *linez, *datax, *datay, *dataz;
l_float32 *linel, *linea, *lineb, *datal, *dataa, *datab;
FPIX *fpix;
FPIXA *fpixad;
PROCNAME("fpixaConvertXYZToLAB");
if (!fpixas || fpixaGetCount(fpixas) != 3)
return (FPIXA *)ERROR_PTR("fpixas undefined/invalid", procName, NULL);
/* Convert XYZ image */
if (fpixaGetFPixDimensions(fpixas, 0, &w, &h))
return (FPIXA *)ERROR_PTR("fpixas sizes not found", procName, NULL);
fpixad = fpixaCreate(3);
for (i = 0; i < 3; i++) {
fpix = fpixCreate(w, h);
fpixaAddFPix(fpixad, fpix, L_INSERT);
}
wpl = fpixGetWpl(fpix);
datax = fpixaGetData(fpixas, 0);
datay = fpixaGetData(fpixas, 1);
dataz = fpixaGetData(fpixas, 2);
datal = fpixaGetData(fpixad, 0);
dataa = fpixaGetData(fpixad, 1);
datab = fpixaGetData(fpixad, 2);
/* Convert XYZ image */
for (i = 0; i < h; i++) {
linex = datax + i * wpl;
liney = datay + i * wpl;
linez = dataz + i * wpl;
linel = datal + i * wpl;
linea = dataa + i * wpl;
lineb = datab + i * wpl;
for (j = 0; j < w; j++) {
fxval = *(linex + j);
fyval = *(liney + j);
fzval = *(linez + j);
convertXYZToLAB(fxval, fyval, fzval, &flval, &faval, &fbval);
*(linel + j) = flval;
*(linea + j) = faval;
*(lineb + j) = fbval;
}
}
return fpixad;
}
/*!
* \brief fpixaConvertLABToXYZ()
*
* \param[in] fpixas lab
* \return fpixa xyz
*
* <pre>
* Notes:
* (1) The input [l,a,b] and output [x,y,z] values are stored as
* float values, each set in three fpix.
* </pre>
*/
FPIXA *
fpixaConvertLABToXYZ(FPIXA *fpixas)
{
l_int32 w, h, wpl, i, j;
l_float32 fxval, fyval, fzval, flval, faval, fbval;
l_float32 *linel, *linea, *lineb, *datal, *dataa, *datab;
l_float32 *linex, *liney, *linez, *datax, *datay, *dataz;
FPIX *fpix;
FPIXA *fpixad;
PROCNAME("fpixaConvertLABToXYZ");
if (!fpixas || fpixaGetCount(fpixas) != 3)
return (FPIXA *)ERROR_PTR("fpixas undefined/invalid", procName, NULL);
/* Convert LAB image */
if (fpixaGetFPixDimensions(fpixas, 0, &w, &h))
return (FPIXA *)ERROR_PTR("fpixas sizes not found", procName, NULL);
fpixad = fpixaCreate(3);
for (i = 0; i < 3; i++) {
fpix = fpixCreate(w, h);
fpixaAddFPix(fpixad, fpix, L_INSERT);
}
wpl = fpixGetWpl(fpix);
datal = fpixaGetData(fpixas, 0);
dataa = fpixaGetData(fpixas, 1);
datab = fpixaGetData(fpixas, 2);
datax = fpixaGetData(fpixad, 0);
datay = fpixaGetData(fpixad, 1);
dataz = fpixaGetData(fpixad, 2);
/* Convert XYZ image */
for (i = 0; i < h; i++) {
linel = datal + i * wpl;
linea = dataa + i * wpl;
lineb = datab + i * wpl;
linex = datax + i * wpl;
liney = datay + i * wpl;
linez = dataz + i * wpl;
for (j = 0; j < w; j++) {
flval = *(linel + j);
faval = *(linea + j);
fbval = *(lineb + j);
convertLABToXYZ(flval, faval, fbval, &fxval, &fyval, &fzval);
*(linex + j) = fxval;
*(liney + j) = fyval;
*(linez + j) = fzval;
}
}
return fpixad;
}
/*!
* \brief convertXYZToLAB()
*
* \param[in] xval, yval, zval input xyz
* \param[out] plval, paval, pbval equivalent lab values
* \return 0 if OK, 1 on error
*/
l_ok
convertXYZToLAB(l_float32 xval,
l_float32 yval,
l_float32 zval,
l_float32 *plval,
l_float32 *paval,
l_float32 *pbval)
{
l_float32 xn, yn, zn, fx, fy, fz;
PROCNAME("convertXYZToLAB");
if (plval) *plval = 0.0;
if (paval) *paval = 0.0;
if (pbval) *pbval = 0.0;
if (!plval || !paval || !pbval)
return ERROR_INT("&lval, &aval, &bval not all defined", procName, 1);
/* First normalize to the corresponding white values */
xn = 0.0041259 * xval;
yn = 0.0039216 * yval;
zn = 0.0036012 * zval;
/* Then apply the lab_forward function */
fx = lab_forward(xn);
fy = lab_forward(yn);
fz = lab_forward(zn);
*plval = 116.0 * fy - 16.0;
*paval = 500.0 * (fx - fy);
*pbval = 200.0 * (fy - fz);
return 0;
}
/*!
* \brief convertLABToXYZ()
*
* \param[in] lval, aval, bval input lab
* \param[out] pxval, pyval, pzval equivalent xyz values
* \return 0 if OK, 1 on error
*/
l_ok
convertLABToXYZ(l_float32 lval,
l_float32 aval,
l_float32 bval,
l_float32 *pxval,
l_float32 *pyval,
l_float32 *pzval)
{
l_float32 fx, fy, fz;
l_float32 xw = 242.37; /* x component corresponding to rgb white */
l_float32 yw = 255.0; /* y component corresponding to rgb white */
l_float32 zw = 277.69; /* z component corresponding to rgb white */
PROCNAME("convertLABToXYZ");
if (pxval) *pxval = 0.0;
if (pyval) *pyval = 0.0;
if (pzval) *pzval = 0.0;
if (!pxval || !pyval || !pzval)
return ERROR_INT("&xval, &yval, &zval not all defined", procName, 1);
fy = 0.0086207 * (16.0 + lval);
fx = fy + 0.002 * aval;
fz = fy - 0.005 * bval;
*pxval = xw * lab_reverse(fx);
*pyval = yw * lab_reverse(fy);
*pzval = zw * lab_reverse(fz);
return 0;
}
/*
* See http://en.wikipedia.org/wiki/Lab_color_space for formulas.
* This is the forward function: from xyz to lab. It includes a rational
* function approximation over [0.008856 ... 1] to the cube root, from
* "Fast Color Space Transformations Using Minimax Approximations",
* M. Celebi et al, http://arxiv.org/pdf/1009.0854v1.pdf.
*/
static l_float32
lab_forward(l_float32 v)
{
const l_float32 f_thresh = 0.008856; /* (6/29)^3 */
const l_float32 f_factor = 7.787; /* (1/3) * (29/6)^2) */
const l_float32 f_offset = 0.13793; /* 4/29 */
if (v > f_thresh) {
#if SLOW_CUBE_ROOT
return powf(v, 0.333333);
#else
l_float32 num, den;
num = 4.37089e-04 + v * (9.52695e-02 + v * (1.25201 + v * 1.30273));
den = 3.91236e-03 + v * (2.95408e-01 + v * (1.71714 + v * 6.34341e-01));
return num / den;
#endif
} else {
return f_factor * v + f_offset;
}
}
/*
* See http://en.wikipedia.org/wiki/Lab_color_space for formulas.
* This is the reverse (inverse) function: from lab to xyz.
*/
static l_float32
lab_reverse(l_float32 v)
{
const l_float32 r_thresh = 0.20690; /* 6/29 */
const l_float32 r_factor = 0.12842; /* 3 * (6/29)^2 */
const l_float32 r_offset = 0.13793; /* 4/29 */
if (v > r_thresh) {
return v * v * v;
} else {
return r_factor * (v - r_offset);
}
}
/*---------------------------------------------------------------------------*
* Colorspace conversion between RGB and LAB *
*---------------------------------------------------------------------------*/
/*!
* \brief pixConvertRGBToLAB()
*
* \param[in] pixs 32 bpp rgb
* \return fpixa lab
*
* <pre>
* Notes:
* (1) The [l,a,b] values are stored as float values in three fpix
* that are returned in a fpixa.
* </pre>
*/
FPIXA *
pixConvertRGBToLAB(PIX *pixs)
{
l_int32 w, h, wpls, wpld, i, j, rval, gval, bval;
l_uint32 *lines, *datas;
l_float32 flval, faval, fbval;
l_float32 *linel, *linea, *lineb, *datal, *dataa, *datab;
FPIX *fpix;
FPIXA *fpixa;
PROCNAME("pixConvertRGBToLAB");
if (!pixs || pixGetDepth(pixs) != 32)
return (FPIXA *)ERROR_PTR("pixs undefined or not rgb", procName, NULL);
/* Convert RGB image */
pixGetDimensions(pixs, &w, &h, NULL);
fpixa = fpixaCreate(3);
for (i = 0; i < 3; i++) {
fpix = fpixCreate(w, h);
fpixaAddFPix(fpixa, fpix, L_INSERT);
}
wpls = pixGetWpl(pixs);
wpld = fpixGetWpl(fpix);
datas = pixGetData(pixs);
datal = fpixaGetData(fpixa, 0);
dataa = fpixaGetData(fpixa, 1);
datab = fpixaGetData(fpixa, 2);
for (i = 0; i < h; i++) {
lines = datas + i * wpls;
linel = datal + i * wpld;
linea = dataa + i * wpld;
lineb = datab + i * wpld;
for (j = 0; j < w; j++) {
extractRGBValues(lines[j], &rval, &gval, &bval);
convertRGBToLAB(rval, gval, bval, &flval, &faval, &fbval);
*(linel + j) = flval;
*(linea + j) = faval;
*(lineb + j) = fbval;
}
}
return fpixa;
}
/*!
* \brief fpixaConvertLABToRGB()
*
* \param[in] fpixa three fpix: l,a,b
* \return pixd 32 bpp rgb
*
* <pre>
* Notes:
* (1) The lab image is stored in three fpix.
* </pre>
*/
PIX *
fpixaConvertLABToRGB(FPIXA *fpixa)
{
l_int32 w, h, wpls, wpld, i, j, rval, gval, bval;
l_float32 flval, faval, fbval;
l_float32 *linel, *linea, *lineb, *datal, *dataa, *datab;
l_uint32 *lined, *datad;
PIX *pixd;
FPIX *fpix;
PROCNAME("fpixaConvertLABToRGB");
if (!fpixa || fpixaGetCount(fpixa) != 3)
return (PIX *)ERROR_PTR("fpixa undefined or invalid", procName, NULL);
/* Convert LAB image */
if (fpixaGetFPixDimensions(fpixa, 0, &w, &h))
return (PIX *)ERROR_PTR("fpixa dimensions not found", procName, NULL);
pixd = pixCreate(w, h, 32);
wpld = pixGetWpl(pixd);
datad = pixGetData(pixd);
datal = fpixaGetData(fpixa, 0);
dataa = fpixaGetData(fpixa, 1);
datab = fpixaGetData(fpixa, 2);
fpix = fpixaGetFPix(fpixa, 0, L_CLONE);
wpls = fpixGetWpl(fpix);
fpixDestroy(&fpix);
for (i = 0; i < h; i++) {
linel = datal + i * wpls;
linea = dataa + i * wpls;
lineb = datab + i * wpls;
lined = datad + i * wpld;
for (j = 0; j < w; j++) {
flval = linel[j];
faval = linea[j];
fbval = lineb[j];
convertLABToRGB(flval, faval, fbval, &rval, &gval, &bval);
composeRGBPixel(rval, gval, bval, lined + j);
}
}
return pixd;
}
/*!
* \brief convertRGBToLAB()
*
* \param[in] rval, gval, bval rgb input
* \param[out] pflval, pfaval, pfbval equivalent lab values
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) These conversions are for illuminant D65 acting on linear sRGB
* values.
* </pre>
*/
l_ok
convertRGBToLAB(l_int32 rval,
l_int32 gval,
l_int32 bval,
l_float32 *pflval,
l_float32 *pfaval,
l_float32 *pfbval)
{
l_float32 fxval, fyval, fzval;
PROCNAME("convertRGBToLAB");
if (pflval) *pflval = 0.0;
if (pfaval) *pfaval = 0.0;
if (pfbval) *pfbval = 0.0;
if (!pflval || !pfaval || !pfbval)
return ERROR_INT("&flval, &faval, &fbval not all defined", procName, 1);
convertRGBToXYZ(rval, gval, bval, &fxval, &fyval, &fzval);
convertXYZToLAB(fxval, fyval, fzval, pflval, pfaval, pfbval);
return 0;
}
/*!
* \brief convertLABToRGB()
*
* \param[in] flval, faval, fbval input lab
* \param[out] prval, pgval, pbval equivalent rgb values
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) For values of lab that are out of gamut for rgb, the rgb
* components are set to the closest valid color.
* </pre>
*/
l_ok
convertLABToRGB(l_float32 flval,
l_float32 faval,
l_float32 fbval,
l_int32 *prval,
l_int32 *pgval,
l_int32 *pbval)
{
l_float32 fxval, fyval, fzval;
PROCNAME("convertLABToRGB");
if (prval) *prval = 0;
if (pgval) *pgval = 0;
if (pbval) *pbval = 0;
if (!prval || !pgval || !pbval)
return ERROR_INT("&rval, &gval, &bval not all defined", procName, 1);
convertLABToXYZ(flval, faval, fbval, &fxval, &fyval, &fzval);
convertXYZToRGB(fxval, fyval, fzval, 0, prval, pgval, pbval);
return 0;
}