This is function in C to convert from Bayer to RGB24 pixel formats.
The linear interpolation is more efficient than the ones I saw in other
similar functions on internet, as the code omits "if-then-else" conditional
statements in the loops.
Best regards,
Luca Risolia
---
/***************************************************************************
* Color convertion from Bayer to RGB24 *
* *
* Copyright (C) Luca Risolia <[EMAIL PROTECTED]> *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the Free Software *
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. *
***************************************************************************/
/*
bayer bgbg...grgr...to rgb24
*/
#define RED 2
#define GREEN 1
#define BLUE 0
#define avg2(x,y) ((((int)(x)) + ((int)(y))) / 2)
#define avg3(x,y,z) ((((int)(x)) + ((int)(y)) + ((int)(z))) / 3)
#define avg4(w,x,y,z) ((((int)(w)) + ((int)(x)) + ((int)(y)) + ((int)(z))) / 4)
void sbggr8_to_rgb24(unsigned char *s, unsigned int x, unsigned int y,
unsigned char *d)
{
unsigned long int i, j;
/* upper left corner */
d[0 + RED] = s[x + 1];
d[0 + BLUE] = s[0];
d[0 + GREEN] = avg2(s[1], s[x]);
/* top line (minus corners) */
i = 1;
while (i < x - 2) {
d[i * 3 + RED] = s[x + i];
d[i * 3 + GREEN] = s[i];
d[i * 3 + BLUE] = avg2(s[i - 1], s[i + 1]);
i++;
d[i * 3 + RED] = avg2(s[x + i - 1], s[x + i + 1]);
d[i * 3 + GREEN] = avg3(s[i - 1], s[i + 1], s[x + i]);
d[i * 3 + BLUE] = s[i];
i++;
}
/* upper right corner */
d[i * 3 + RED] = s[x + i];
d[i * 3 + GREEN] = s[i];
d[i * 3 + BLUE] = s[i - 1];
/* middle lines */
j = 1;
while (j < y - 2) {
d[j * x * 3 + RED] = s[j * x + 1];
d[j * x * 3 + GREEN] = s[j * x];
d[j * x * 3 + BLUE] = avg2(s[(j - 1) * x], s[(j + 1) * x]);
i = 1;
while (i < x - 2) {
d[(j * x + i) * 3 + RED] = s[j * x + i];
d[(j * x + i) * 3 + GREEN] = avg4(s[(j - 1) * x + i],
s[j * x + i - 1],
s[j * x + i + 1],
s[(j + 1) * x + i]);
d[(j * x + i) * 3 + BLUE] =
avg4(s[(j - 1) * x + i - 1],
s[(j - 1) * x + i + 1],
s[(j + 1) * x + i - 1],
s[(j + 1) * x + i + 1]);
i++;
d[(j * x + i) * 3 + RED] = avg2(s[j * x + i - 1],
s[j * x + i + 1]);
d[(j * x + i) * 3 + GREEN] = s[j * x + i];
d[(j * x + i) * 3 + BLUE] = avg2(s[(j - 1) * x + i],
s[(j + 1) * x + i]);
i++;
}
d[(j * x + i) * 3 + RED] = s[j * x + i];
d[(j * x + i) * 3 + BLUE] = avg2(s[(j - 1) * x + i - 1],
s[(j + 1) * x + i - 1]);
d[(j * x + i) * 3 + GREEN] = avg3(s[(j - 1) * x + i],
s[(j + 1) * x + i],
s[j * x + i - 1]);
j++;
d[j * x * 3 + RED] = avg2(s[(j - 1) * x + 1],
s[(j + 1) * x + 1]);
d[j * x * 3 + BLUE] = s[j * x];
d[j * x * 3 + GREEN] = avg3(s[(j - 1) * x],
s[j * x + 1],
s[(j + 1) * x]);
i = 1;
while (i < x - 2) {
d[(j * x + i) * 3 + RED] = avg2(s[(j - 1) * x + i],
s[(j + 1) * x + i]);
d[(j * x + i) * 3 + GREEN] = s[j * x + i];
d[(j * x + i) * 3 + BLUE] = avg2(s[j * x + i - 1],
s[j * x + i + 1]);
i++;
d[(j * x + i) * 3 + RED] = avg4(s[(j - 1) * x + i - 1],
s[(j - 1) * x + i + 1],
s[(j + 1) * x + i - 1],
s[(j + 1) * x + i + 1]);
d[(j * x + i) * 3 + GREEN] = avg4(s[(j - 1) * x + i],
s[j * x + i - 1],
s[j * x + i + 1],
s[(j + 1) * x + i]);
d[(j * x + i) * 3 + BLUE] = s[j * x + i];
i++;
}
d[(j * x + i) * 3 + RED] = avg2(s[(j - 1) * x + i],
s[(j + 1) * x + i]);
d[(j * x + i) * 3 + BLUE] = s[j * x + i - 1];
d[(j * x + i) * 3 + GREEN] = s[j * x + i];
j++;
}
/* lower left corner */
d[(j * x) * 3 + RED] = s[j * x + 1];
d[(j * x) * 3 + GREEN] = s[j * x];
d[(j * x) * 3 + BLUE] = s[(j - 1) * x];
/* bottom line */
i = 1;
while (i < x - 2) {
d[(j * x + i) * 3 + RED] = s[j * x + i];
d[(j * x + i) * 3 + GREEN] = avg3(s[(j - 1) * x + i],
s[j * x + i - 1],
s[j * x + i + 1]);
d[(j * x + i) * 3 + BLUE] = avg2(s[(j - 1) * x + i - 1],
s[(j - 1) * x + i + 1]);
i++;
d[(j * x + i) * 3 + RED] = avg2(s[j * x + i - 1],
s[j * x + i + 1]);
d[(j * x + i) * 3 + GREEN] = s[j * x + i];
d[(j * x + i) * 3 + BLUE] = s[(j - 1) * x + i];
i++;
}
/* lower right corner */
d[(j * x + i) * 3 + RED] = s[j * x + i];
d[(j * x + i) * 3 + GREEN] = avg2(s[(j - 1) * x + i],
s[j * x + i - 1]);
d[(j * x + i) * 3 + BLUE] = s[(j - 1) * x + i - 1];
}
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