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SimpleSkyCam/debayer.cc

367 lines
7.4 KiB

#include <stdio.h>
#include <stdint.h>
/*
The function converts a 16bit GRBG 2x2 CFA coded image into an 8bit
RGB image by setting the missing RGB values to zero.
*/
void debayer_grbg16_simple (uint16_t * src, int src_w, int src_h,
uint8_t * dst, int dst_w, int dst_h) {
// GG RR
// BB GG
uint16_t t;
uint8_t r, g, b;
int ys, yd, xs, xd;
for (ys = 0, yd = 0; ys < src_h && yd < dst_h; ys++, yd++) {
for (xs = 0, xd = 0; xs < src_w; xs++) {
/* read the pixel but only the higher 8bit, assuming data is little endian */
t = (*(src++) >> 8) & 0xff;
if (xs & 1) {
if (ys & 1) {
// lower right green pixel
b = 0; g = t; r = 0;
} else {
// upper right red pixel
b = 0; g = 0; r = t;
}
} else {
if (ys & 1) {
// lower left blue pixel
b = t; g = 0; r = 0;
} else {
// upper left green pixel
b = 0; g = t; r = 0;
}
}
/* only paint the image if the source is within the destination */
if (xd < dst_w) {
/* set the pixel */
*(dst++) = r;
*(dst++) = g;
*(dst++) = b;
xd++;
}
}
/* if the source image is too small ignore the other places */
if (xd < dst_w)
dst += 3 * (dst_w - xd);
}
}
// macros to make code better readable
#define CE (*(src))
#define UP (*(src-src_w))
#define DN (*(src+src_w))
#define LE (*(src-1))
#define RI (*(src+1))
#define UPLE (*(src-src_w-1))
#define UPRI (*(src-src_w+1))
#define DNLE (*(src+src_w-1))
#define DNRI (*(src+src_w+1))
#define BITCONV(d) ((d>>8) & 0xff)
#define STORE *(dst++) = BITCONV(r); *(dst++) = BITCONV(g); *(dst++) = BITCONV(b); src++;
#define STORE8 *(dst++) = (r & 0xff); *(dst++) = (g & 0xff); *(dst++) = (b & 0xff); src++;
/*
The function converts a 16bit GRBG 2x2 CFA coded image into an 8bit
RGB image by bilinear interpolation.
*/
void debayer_grbg16_bilinear (uint16_t * src, int src_w, int src_h,
uint8_t * dst, int dst_w, int dst_h) {
// GG RR GG RR
// BB GG BB GG
// GG RR GG RR
// BB GG BB GG
uint32_t r, g, b;
int xs, ys;
// start with upper left pixel (green)
r = RI;
g = CE;
b = DN;
STORE;
// upper first line, starts with RR GG RR ...
for (xs = 1; xs < src_w - 1; xs+=2) {
// red pixel
r = CE;
g = (LE + RI + DN) / 3;
b = (DNLE + DNRI) / 2;
STORE;
// green pixel
r = (LE + RI) / 2;
g = CE;
b = DN;
STORE;
}
// upper right pixel (red)
r = CE;
g = (DN + LE) / 2;
b = DNLE;
STORE;
// go through the "body" of the image
for (ys = 1; ys < src_h - 1; ys+=2) {
// every second line with BB GG BB GG (start at 2nd line)
// left hand pixel (blue)
r = (UPRI + DNRI) / 2;
g = (UP + DN + RI) / 3;
b = CE;
STORE;
for (xs = 1; xs < src_w - 1; xs+=2) {
// green pixel
r = (UP + DN) / 2;
g = CE;
b = (LE + RI) / 2;
STORE;
// blue pixel
r = (UPLE + UPRI + DNLE + DNRI) / 4;
g = (LE + RI + UP + DN) / 4;
b = CE;
STORE;
}
// last pixel in line (green)
r = (UP + DN) / 2;
g = CE;
b = LE;
STORE;
// every second line with GG RR GG RR ... (start at 3rd line)
// left hand pixel (green)
r = RI;
g = CE;
b = (UP + DN) / 2;
STORE;
for (xs = 1; xs < src_w - 1; xs+=2) {
// red pixel
r = CE;
g = (LE + RI + UP + DN) / 4;
b = (UPLE + UPRI + DNLE + DNRI) / 4;
STORE;
// green pixel
r = (LE + RI) / 2;
g = CE;
b = (UP + DN) / 2;
STORE;
}
// last pixel in line (red)
r = CE;
g = (UP + DN + LE) / 3;
b = (UPLE + DNLE) / 2;
STORE;
}
// bottom left pixel
r = UPRI;
g = (UP + RI) / 2;
b = CE;
STORE;
// last line starting with GG BB GG ...
for (xs = 1; xs < src_w - 1; xs+=2) {
// green pixel
r = UP;
g = CE;
b = (LE + RI) / 2;
STORE;
// blue pixel
r = (UPLE + UPRI) / 2;
g = (LE + UP + RI) / 2;
b = CE;
STORE;
}
// bottom right pixel (green)
r = UP;
g = CE;
b = LE;
STORE;
}
/*
The function converts a 8bit GRBG 2x2 CFA coded image into an 8bit
RGB image by setting the missing RGB values to zero.
*/
void debayer_grbg8_simple (uint8_t * src, int src_w, int src_h,
uint8_t * dst, int dst_w, int dst_h) {
// GG RR
// BB GG
uint8_t t;
uint8_t r, g, b;
int ys, yd, xs, xd;
for (ys = 0, yd = 0; ys < src_h && yd < dst_h; ys++, yd++) {
for (xs = 0, xd = 0; xs < src_w; xs++) {
/* read the pixel but only the higher 8bit, assuming data is little endian */
t = *(src++);
if (xs & 1) {
if (ys & 1) {
// lower right green pixel
b = 0; g = t; r = 0;
} else {
// upper right red pixel
b = 0; g = 0; r = t;
}
} else {
if (ys & 1) {
// lower left blue pixel
b = t; g = 0; r = 0;
} else {
// upper left green pixel
b = 0; g = t; r = 0;
}
}
/* only paint the image if the source is within the destination */
if (xd < dst_w) {
/* set the pixel */
*(dst++) = r;
*(dst++) = g;
*(dst++) = b;
xd++;
}
}
/* if the source image is too small ignore the other places */
if (xd < dst_w)
dst += 3 * (dst_w - xd);
}
}
/*
The function converts a 8bit GRBG 2x2 CFA coded image into an 8bit
RGB image by bilinear interpolation.
*/
void debayer_grbg8_bilinear (uint8_t * src, int src_w, int src_h,
uint8_t * dst, int dst_w, int dst_h) {
// GG RR GG RR
// BB GG BB GG
// GG RR GG RR
// BB GG BB GG
uint16_t r, g, b;
int xs, ys;
// start with upper left pixel (green)
r = RI;
g = CE;
b = DN;
STORE8;
// upper first line, starts with RR GG RR ...
for (xs = 1; xs < src_w - 1; xs+=2) {
// red pixel
r = CE;
g = (LE + RI + DN) / 3;
b = (DNLE + DNRI) / 2;
STORE8;
// green pixel
r = (LE + RI) / 2;
g = CE;
b = DN;
STORE8;
}
// upper right pixel (red)
r = CE;
g = (DN + LE) / 2;
b = DNLE;
STORE8;
// go through the "body" of the image
for (ys = 1; ys < src_h - 1; ys+=2) {
// every second line with BB GG BB GG (start at 2nd line)
// left hand pixel (blue)
r = (UPRI + DNRI) / 2;
g = (UP + DN + RI) / 3;
b = CE;
STORE8;
for (xs = 1; xs < src_w - 1; xs+=2) {
// green pixel
r = (UP + DN) / 2;
g = CE;
b = (LE + RI) / 2;
STORE8;
// blue pixel
r = (UPLE + UPRI + DNLE + DNRI) / 4;
g = (LE + RI + UP + DN) / 4;
b = CE;
STORE8;
}
// last pixel in line (green)
r = (UP + DN) / 2;
g = CE;
b = LE;
STORE8;
// every second line with GG RR GG RR ... (start at 3rd line)
// left hand pixel (green)
r = RI;
g = CE;
b = (UP + DN) / 2;
STORE8;
for (xs = 1; xs < src_w - 1; xs+=2) {
// red pixel
r = CE;
g = (LE + RI + UP + DN) / 4;
b = (UPLE + UPRI + DNLE + DNRI) / 4;
STORE8;
// green pixel
r = (LE + RI) / 2;
g = CE;
b = (UP + DN) / 2;
STORE8;
}
// last pixel in line (red)
r = CE;
g = (UP + DN + LE) / 3;
b = (UPLE + DNLE) / 2;
STORE8;
}
// bottom left pixel
r = UPRI;
g = (UP + RI) / 2;
b = CE;
STORE8;
// last line starting with GG BB GG ...
for (xs = 1; xs < src_w - 1; xs+=2) {
// green pixel
r = UP;
g = CE;
b = (LE + RI) / 2;
STORE8;
// blue pixel
r = (UPLE + UPRI) / 2;
g = (LE + UP + RI) / 2;
b = CE;
STORE8;
}
// bottom right pixel (green)
r = UP;
g = CE;
b = LE;
STORE8;
}